amardeep report

DESIGN AND STUDY OF SWIRL INJECTOR OF PULSE DETONATION ENGINE

INDUSTRIAL TRAINING REPORT (JULY 2015 – DEC 2015)


AT

TERMINAL BALLISTICS RESEARCH LABORATORY (T.B.R.L.),

Submitted by

AMARDEEP SINGH

1252577

Under the Guidance of

MR. MUNESH KUMAR PATLE

SCIENTIST ‘D’

PULSE DETONATION SYSTEM GROUP

In partial fulfillment for the award of the degree of

BACHELOR OF TECHNOLOGYIN

AERONAUTICAL ENGINEERING

1Gurukul Vidyapeeth Institute of Engg & Tech


Certificate



DECLARATION

I hereby declare that this TRAINING REPORT “DESIGN & STUDY OF SWIRL

INJECTOR OF PULSE DETONATION ENGINE “ by AMARDEEP SINGH (1252577),

being submitted in partial fulfillment of the requirements for the degree of Bachelor of

Technology in AERONAUTICAL ENGINEERING BRANCH under Faculty of GURUKUL

VIDYAPEETH INSTITUTE OF ENGINEERING AND TECHNOLOGY, during the academic

year 2015-16, is a bonafide record of my work carried out in the TERMINAL BALLISTICS

RESEARCH LABORATORY,CHANDIGARH under guidance and supervision of

MR.MUNESH KUMAR PATLE, Sc.’D’ (Pulse Detonation Systems) and has not been

presented elsewhere.

Date………… AMARDEEP SINGH

(1252577)

Certified that the above statement made by the student is correct to the best of our knowledge

and belief.

TRAINING HEAD

Mr. Munesh Kumar Patle

Scientist ‘D’

DIVISION HEAD JOINT DIRECTOR

Mr. Manmohan Sandhu Mr. Subhash Chander

Scientist ‘E’ Scientist ‘F’

PDS Group Zone – I



ABSTRACT

Pulse Detonation is a propulsion technology that involves detonation of fuel to

produce thrust more efficiently than current engine systems. By literature survey and library

research, it is shown that Pulse Detonation Engine (PDE) technology is more efficient than

current engine types by virtue of its mechanical simplicity and thermodynamic efficiency. As

the PDE produces higher specific thrust than comparable ramjet, scramjet engines at speeds of

up to approximately Mach 2.3 to 5, it is suitable to use as part of a multistage propulsion system.

The PDE can provide static thrust for a ramjet or scramjet engine, or operate in combination

with turbofan systems. As such it sees potential applications in many sectors of the Aerospace,

Aeronautics and Military industries. However, there remain engineering challenges that must be

overcome before the PDE can see practical use. Current methods for initiating the detonation

process need refinement. To this end, many government and private organizations around the

world are working on PDS research and further development.

In India, DRDO’s TERMINAL BALLISTICS RESEARCH LABORATORY (TBRL) is

also working on such an advanced and challenging technology of Pulse Detonation Engine. I

have undergone my 6 months industrial training on this advanced field in the areas of

introductory study/knowledge of PDE Theory and Design & Development of Swirl injector of a

PDE.



CONTENT1.ORGANISATION DETAILS

1.1 MISISTRY OF DEFRNCE……….

1.2 DEFENCE RESEACH & DEVELOPMENT ORGANISATION (DRDO)………………...

1.3 LABORATORIES AND ESTABLISHMENTS…………………

1.4 TERMINAL BALLISTICS RESEARCH LABORATORY (TBRL)………………..

1.4.1 VISION, MISSION AND CHARTER OF DUTY

1.4.2 AREAS OF WORK

1.4.3 ACHIEVEMENTS

2. INTRODUCTION TO PULSE DETONATION

2.1 INTRODUCTION………………………

2.2 DETONATION V/S DEFLAGRATION…………….

2.3 MAIN COMPONENTS OF PDE…………….

2.4 WORKING CYCLES ………….

2.5 STAGES OF PDE…………….

2.6 COMPARISON OF VARIOUS PROPULSION SYSTEM…………….

3. FUEL INJECTION

3.1 REQUIREMENT OF INJECTORS………………………

3.2 SWIRL INJECTOR……………………………

3.2.1 INTRODUCTION

3.2.2 SWIRLER

3.2.3 INTERNAL FLOW OF SWIRLER

3.2.4 ADVANTAGES OF SWIRL INJECTOR

3.2.5 PULSATING FLOW OF SWIRL INJECTOR



4. SPRAY FORMATION

4.1 INTRODUCTION………………………………..

4.1 EFFECT OF SWIRLER IN SPRAY FORMATION………………………….

5. DROPLET SIZE DISTRIBUTION

6.CALCULATION AND DESIGN PART

7.HELIX ANGLE FOR SWIRLER

8.OBSERVATIONS

9.SOLID MODELS

10. EXPERIMENTAL SET –UP

10.1 SET UP…………………………………………….

10.2 OBJECTIVES OF SET UP………………………………

10.3 PROCEDURE FOR MMD …………………………………

10.4 MIXING…………………………………..

11.CONCLUSION

12.REFERENCES

13.APPENDIX



Defence Research & Development Organization

(D.R.D.O.)

Drdo Logo

Ministry of Defence

Before India became an independent nation in 1947, the defence of the country was the

responsibility of the Defence Department (under the British rule). Soon after India became

independent, the Defence Department became the Ministry of Defence, headed by a Minister of

the Cabinet Rank. According to the Constitution of India, the President of India is the supreme

commander of the Armed Forces and executive responsibility for national defence rests with the

Union Cabinet of which Defence Minister is an important member. The official designation of

the Defence Minister is Raksha Mantri (RM) who is assisted by a Ministry of State called Rajya

Raksha Mantry (RRM) assisting the RM.

Defence Research & Development Organisation

Defence Research & Development Organization (DRDO) works under Department of

Defence Research and Development of Ministry of Defence. DRDO is dedicatedly working

towards enhancing self-reliance in Defence Systems and undertakes design & development

leading to production of world class weapon systems and equipment in accordance with the

expressed needs and the qualitative requirements.DRDO while striving to meet the Cutting edge

weapons technology requirements provides ample spinoff benefits to the society at large thereby

contributing to the nation building.DRDO makes India prosperous by establishing world-class

science and technology base andprovide our Defence Services decisive edge by equipping them

with internationally competitivesystems and solutions.



The Defence Research and Development Organisation (DRDO) is an agency of

the Republic of India, responsible for the development of technology for use by the military,

headquartered in New Delhi, India. It was formed in 1958 by the merger of the Technical

Development Establishment and the Directorate of Technical Development and Production with

the Defence Science Organisation. It is under the administrative control of the Ministry of

Defence, Government of India. Prof. DS Kothari, the eminent scientist and educationist was the

first to head the Organization which has been led over the years by illuminati of the caliber of Dr

APJ Abdul Kalam. Sir S Christopher is the current head of the DRDO.

DRDO Bhawan, Headquarters at New Delhi

The 52 DRDO labs, based on their core-competence, are classified into nine clusters, namely,

Aeronautics, Armaments, Combat Vehicles and Engineering, Electronics and Computer

Sciences, Materials, Missiles and Strategic Systems, Micro Electronics and Devices, Naval

Research and Development, and Life Sciences. Devoted to innovation and excellence, DRDO

remains committed to make India strong and self-reliant. It has designed, developed and product

ionized world-class weapon systems, equipment, and complex technologies, which include

strategic and tactical missiles, combat aircrafts and aeronautical systems, unmanned aerial

vehicles, combat vehicles, armaments and ammunition, radars, electro-optic and acoustic

sensors, electronic warfare systems, life-support systems and materials. The production value

ofMajor DRDO systems inducted into the Services during the last decade stands at over Rs 1,

20,000 crores. Presently, the Organization is backed by over 5000 scientists and about 25,000

other scientific, supporting personnel.

8

Gurukul Vidyapeeth Institute of Engg & Tech

http://en.wikipedia.org/wiki/Government_of_India

http://en.wikipedia.org/wiki/Ministry_of_Defence_(India)

http://en.wikipedia.org/wiki/Ministry_of_Defence_(India)

http://en.wikipedia.org/wiki/New_Delhi

http://en.wikipedia.org/wiki/Military_of_India

http://en.wikipedia.org/wiki/Republic_of_India

http://en.wikipedia.org/wiki/Government_agency


Laboratories

Aeronautics

Aeronautical Development Establishment (ADE), Bangalore

Aerial Delivery Research & Development Establishment (ADRDE), Agra

Centre for Air Borne Systems (CABS), Bangalore

Defense Avionics Research Establishment (DARE), Bangalore

Gas Turbine Research Establishment (GTRE), Bangalore

Center for Military Airworthiness & Certification (CEMILAC), Bangalore.

Aeronautics

Armaments

Armament Research & Development Establishment (ARDE), Pune

Centre for Fire, Explosive & Environment Safety (CFEES), Delhi

High Energy Materials Research Laboratory (HEMRL), Pune

Proof & Experimental Establishment (PXE), Balasore

Combat Vehicles and Engineering

Combat Vehicles Research & Development Est. (CVRDE), Chennai

Vehicle Research & Development Establishment (VRDE), Ahmednagar

Research & Development Establishment (R&DE), Pune

Snow & Avalanche Study Estt (SASE), Chandigarh



Combat Vehicles Armaments

Electronics & Computer Sciences

Advanced Numerical Research & Analysis Group (ANURAG), Hyderabad

Center for Artificial Intelligence & Robotics (CAIR), Bangalore

DRONA CELL, Delhi

Defence Electronics Application Laboratory (DEAL), Dehradun

Defence Electronics Research Laboratory (DLRL), Hyderabad

Defence Terrain Research Laboratory (DTRL), Delhi

Defence Scientific Information & Documentation Centre (DESIDOC), Delhi

Instruments Research & Development Establishment (IRDE), Dehradun

Laser Science & Technology Centre (LASTEC), Delhi

Electronics & Radar Development Establishment (LRDE), Bangalore

Microwave Tube Research & Development Center (MTRDC), Bangalore

Scientific Analysis Group (SAG), Delhi

Solid State Physics Laboratory (SSPL), Delhi



Life Sciences

Defence Agricultural Research Laboratory (DARL), Pithoragarh

Defence Bio-Engineering & Electro Medical Laboratory (DEBEL), Bangalore.

Defence Food Research Laboratory (DFRL), Mysore.

Defence Institute of Physiology & Allied Sciences (DIPAS), Delhi

Defence Institute of Psychological Research (DIPR), Delhi

Institute of Nuclear Medicine & Allied Sciences (INMAS), Delhi

Defence Research & Development Establishment (DRDE), Gwalior

Materials

Defence Laboratory (DLJ), Jodhpur

Defence Metallurgical Research Laboratory (DMRL), Hyderabad

Defence Materials & Stores Research & Development Establishment (DMSRDE),

Kanpur

Missiles

Defence Research & Development Laboratory (DRDL), Hyderabad

Institute of Systems Studies & Analyses (ISSA), Delhi

Integrated Test Range (ITR), Balasore

Research Center Imaret (RCI), Hyderabad

Terminal Ballistics Research Laboratory (TBRL), Chandigarh



Naval Research & Development

Naval Materials Research Laboratory (NMRL), Ambernath

Naval Physical & Oceanographic Laboratory

(NPOL), Cochin

Naval Science & Technological Laboratory (NSTL), Vishakhapatnam

Navy Research & Development

Missiles



Terminal Ballistics Research Laboratory

Terminal Ballistics Research Laboratory (TBRL) was envisaged in 1961 as one of the

modern armament research laboratories under the Department of Defence Research &

Development. The laboratory became fully operational in 1967 and was formally inaugurated in

January 1968 by the then Defence Minister. While the main laboratory is situated in Chandigarh,

the firing range, spread over an area of 5500 acre, is located at Ramgarh in Haryana, 22 km

away from Chandigarh. Over the past three decades, the Laboratory has grown into an

institution of excellence and has become one of the major technical bases in the field of

armament studies in DRDO.

The laboratory has it’s headquarter at Sector 30, Chandigarh and technical area known as

TBRL Ranges, spread over 5500 acres at Village Ramgarh, Distt. Panchkula, Haryana. TBRL

Ranges are divided into a number of technical zones / trial areas which have been so designed

and spaced to allow conduct of experimental trials independent of each other. Each technical

zone has been equipped with highly specialized instruments and diagnostic facilities, which

generate critical inputs for the design and development of warheads and other armament system.

The main features of the trial areas are that the instruments are kept in strong RCC bunkers and

explosive or ammunition are detonated in the open. This gives flexibility in operation and

permits explosion of high calibre warheads, ammunition and large explosive charges with

adequate safety measures.

The laboratory is certified as per International Quality Management Systems Standard

ISO 9001:2008 by Standardization Testing and Quality Certification Services (STQC),

Department of Information Technology (DIT), Government of India.



Vision, Mission and Charter of Duty

Vision

Terminal Ballistics Research Laboratory envisaged self-reliance in the development of

the technologies related to conventional and nonconventional Warhead systems and provide

state-of-art diagnostics facilities for assessment of terminal effects of armament system.

Mission

Terminal Ballistics Research Laboratory will strive for self-sufficiency and self-reliance

in critical areas for development of technologies related to conventional and non-

conventional weapons and provides facilities for transient phenomenon studies for

development of new armament stores.

Charter of Duty

To conduct basic and applied research work in detonics, energetic materials, blast and

damage, defeat of armour, immunity and lethality, design, development and performance

evaluation of armament stores.

Areas of Work

TBRL conducts basic and applied research in the fields of high explosives, detonics

and shock waves. It is also involved in evolving data and design parameters for new armaments,

as well as assessing the terminal effects of ammunition.

Other areas of work include:

Performance of armour defeating projectiles and immunity profiles.

Studies of ground shock, blast damage, fragmentation and lethality.

Preparation of safety templates for various weapons.

Studies of underwater detonics and pressure wave propagation


http://en.wikipedia.org/wiki/Terminal_ballistics

http://en.wikipedia.org/wiki/Shock_wave

http://en.wikipedia.org/wiki/High_explosives


Explosive forming, cladding and welding.

Detonics of high explosives.

Applied research in detonics

Technology for design and development of Shaped Charges and Explosively Formed

Penetrators for anti-tank, anti-ship and anti-submarine applications

Technology for generation of high energy electrical pulse power through explosive

driven magnetic flux compression

Blast, Lethality and Fragmentation studies of warheads, shells and other ammunitions.

Captive flight testing of Bombs, Missiles and Airborne systems.

Ballistics evaluation of various protective system like body armour, vehicle armour and

helmets against small arm ammunition.

Design and development of Baffle Ranges, Warhead and Exploder for Torpedoes, Bund

Blasting Devices, Multi-mode Hand Grenade, Non-lethal plastic and frangible bullets,

High voltage- high energy electrical power packs.

Achievements

Establishment of Ultra High Speed photography and Flash Radio photography

(300 KV) techniques in 1968.

Bund blasting device inducted into service with 1440 Nos. of Limited Service Production

order -2002.

ISO 9001: 2000 / certification granted by STQC, New Delhi in Jan 2005

Baffle Rang-Smart Solution for small arms practice firing.

TBRL has designed and developed Bund Blasting Device, based on the principle of

hollow charge and a rocket assisted high explosive filled follow through projectile.

Multi-mode Hand Grenade.

Warhead and Exploder of torpedo advanced and light (TAL).

Non-lethal ammunition-Plastic bullets, frangible ceramic and metal ammunition.

Explosive driven high energy pulse power technology.

Shaped Charges & Explosive Formed Projectile (EFP).

Developed Indigenous plastic bonded explosives, digital blast data recorder, indigenous transducer for blast measurement, Impulse generator.

Pulse Detonation System (PDS). Rail Track Rocket Sled (RTRS) National Test Facility.



PULSE DETONATION ENGINE

Introduction of Pulse Detonation Engine

In a ll air breathing and rocket engines, oxidizer and fuel

combustion takes place at lower speed i.e. velocity of 20-30 m/sec. It is called subsonic

combustion or deflagration combustion. The pulse detonation engine is another innovative

concept of air breathing engine, which is currently in active development that operates on

detonation combustion principle. Pulse detonation engines (PDEs) have received

considerable attention over the past decade. These engine use detonation waves that propagates

through a premixed fuel/air mixture and produce large chamber pressure and thereby thrust.

Because the combustion takes place so rapidly, the charge (fuel/air mix) does not have time to

expand during this process, so it takes place under almost constant volume. Constant volume

combustion is more efficient than open-cycle designs like gas turbines, which leads to

greater fuel efficiency. PDEs are predicted to be very efficient and offer good thrust

characteristics from the low subsonic to the high supersonic flight regimes, but the engine

operates in a pulsed mode, so the thrust is varying in time and the detonation must be initiated

each time. The system is complicated because fast purging and refilling are required.

Schematic of a basic pulse detonation engine with valves at the inlet and a nozzle at the exhaust



Detonation v/s Deflagration

Detonation is a supersonic combustion process which is essentially a shock front driven

by the energy release of the reaction zones in the flow right behind it. The shock wave is very

thin, being only a few molecular mean-free-paths in width. The reaction zone may be much

thicker and can be a few mm in width under normal conditions. The shock wave and the reaction

zones are tightly coupled in a detonation wave and together move at supersonic speeds through

the medium at a few thousand meters per second.

On the other hand, deflagration is a subsonic combustion process in which a flame front

passes through the reactant mixture (or vice versa) with flame speeds from less than a few

meters per second to a few hundred meters per second, releasing the heat of reaction at a much

slower pace. In the case of scramjets, the flow may be moving at supersonic speeds, but the

reaction is still termed as a deflagration process because of the lack of shock waves.

Deflagration can be premixed or non-premixed (diffusive). For propulsion applications the

premixed reaction is preferred over improperly mixed or unmixed diffusion reactions.

Detonation v/s Deflagration17



Main components of PDE

Schematic of the PDE showing the main components

Pre-detonator :-

The pre-detonator design was chosen because of its simplicity. At the cost of a

small amount of oxygen carried on board, the pre-detonator provides an effortless means of

igniting the propane-oxygen mixture quickly with low energy sparks, and makes it possible to

transmit an accelerated detonation wave into a less energetic fuel-air mixture.

Shchelkin Spiral :-

The pre-detonator has the option of being fitted with a long Shchelkin spiral. The

spiral is welded to a flange that enables it to be bolted to the flange of the pre-detonator. The

Shchelkin spiral is used to over-drive the detonation wave so that it may be successfully

transmitted through the nozzle without decoupling.

DDT devices

The deflagration-to-detonation transition (DDT) is a process by which a deflagration

flame front is gradually accelerated to form a supersonic detonation wave. As the flame is

pushed downstream by the expansion of the burnt gases behind it, the flame front becomes

curved and wrinkled by the effects of the boundary layer in front of the flame, flame instabilities

and turbulence. As a result, the surface area of the flame grows which increases the rate of

reaction of the fuel and oxidizer. Thus, the rate of release of energy is amplified causing the



flame front to be accelerated at an even faster rate. Finally, the increased energy release leads to

the formation of one or more localized explosions and the transformation of the flame into a

detonation wave.

It has been verified that placing certain obstacles in the flow significantly reduces the

DDT run-up distance. These objects are called DDT devices. The effect that DDT devices

generate is to increase turbulence and the thickness of the boundary layer in the flow and to

create instabilities in the flame front.

The most commonly used device is the Shchelkin spiral, which is named after K.I.

Shchelkin, who discovered it, while studying the effects of wall roughness on detonation, in the

late 1930s. The Shchelkin spiral is essentially a helical spring made from thick rigid wire. The

parameters of the spiral are length, blockage ratio and pitch. The blockage ratio of the spiral or

any cylindrical DDT device is given in terms of its internal and external diameters, d and D

respectively, and thickness t , as follows.

Schematic of the shchelkin spiral

Shchelkin spiral

Nozzle:

The nozzle was designed to transmit the detonation wave with minimal loss of

velocity. It was found that larger diverging angles or abrupt transition of area cause detonation



waves to decouple, due to the excessive curvature of the detonation wave and the cooling of the

flow due to the rapid expansion.

Main Combustion Chamber with Swirl Injector Block : -

The carbon steel collars hold pressure and optical transducer ports and contain

orifices for water to circulate through them, and also provide additional strength to the tube. The

combustor tube is covered with a layer of sheet metal in between the collars, forming a water

cooling jacket. Water is pumped in through four tubes bored into the wall of the main flange on

the left and the water exits the cooling cavity through four tubes welded to the last collar on the

right hand side of the tube. At the left hand end of the main combustor is the swirl injector

block, which has four ports through which a fuel-air mixture is pumped in.

WORKING CYCLE OF PDE

Humphrey cycle

The Humphrey cycle is a thermodynamic cycle used in pulse detonation engine. It may be

considered to be a modification of the Brayton cycle in which the constant-pressure heat

addition process of the Brayton cycle is replaced by a constant-volume heat addition process.

Hence, the ideal Humphrey cycle consists of 4 processes:

1. Reversible, adiabatic (isentropic) compression of the incoming gas. During this step

incoming gas is compressed, usually by turbomachinery. Stagnation pressure and

temperature increase because of the work done on the gas by the compressor. Entropy is

unchanged. Static pressure and density of the gas increase.

2. Constant-volume heat addition. In this step, heat is added while the gas is kept at

constant volume. In most cases, Humphrey-cycle engines are considered open cycles

(meaning that air flows through continuously), so this means that the specific volume (or

density) remains constant throughout the heat addition process. Heat is usually added by

combustion.

3. Reversible, adiabatic (isentropic) expansion of the gas. During this step incoming gas

is expanded, usually by turbomachinery. Stagnation pressure and temperature decrease

because of the work extracted from the gas by the turbine. Entropy is unchanged. Static

pressure and density of the gas decrease.



4. Constant-pressure heat rejection. In this step, heat is removed from the working fluid

while the fluid remains at constant pressure. In open-cycle engines this process usually

represents expulsion of the gas from the engine, where it quickly equalizes to ambient

pressure and slowly loses heat to the atmosphere, which is considered to be an infinitely

large reservoir for heat storage, with constant pressure and temperature.

Efficiency of Humphrey cycle

դ = 1-γT 0

T 1[¿¿]

Comparison of brayton and humphrey thermodynamic cycles

Thermal efficiencies comparison of Brayton and Humphrey cycles at different degrees of pressure



Stages of PDE

The PDE cycle has four stages, namely1. fill2. combustion3. blow down (exhaust)4. purge.

The PDE combustion chamber is filled with fuel and oxidizer during the fill stage. The time taken for the filling is denoted as t f . When the fuel-oxidizer mixture is filled to the required volume, the combustion stage commences when a spark (arc or any other ignition initiator) is fired to start ignition. A detonation wave is soon created that moves through the mixture and causes the pressure and temperature behind it to rapidly shoot up. The time taken for the detonation wave to take shape and to move through to the end of the combustion chamber is denoted by t c. The next stage is the blow down stage, when a series of rarefaction waves travel upstream into the combustion chamber and reflect off the end wall, causing the high pressure burnt gases to exit the combustion chamber at a high speed. The time taken for the blow down stage is denoted by t b. This is then followed by the purge stage, when fresh air is blown through to clean and cool the tube before the fill stage starts again. The time taken for purging the tube with fresh air is denoted by t p

The purging process is very important as this cools the tube and prevents the fresh fuel oxidizer mixture from igniting due to residual heat on entry into the combustion chamber. It also protects the structure of the tube from heat buildup. The amount of time that the fuel-oxidizer mixture remains within the detonation tube is known as the residence time. At higher speeds, the residence time is very short, in the order of a few ms, and the combustion has to be initiated and advanced to detonation in as short as 1 to 5 ms.

The total time period τ of one cycle is the sum of all the four stages, namely, τ = t f + t c+ t b+ t p

Four stages of a pulse detonation engine cycle.



Schematic diagram of the pulse-detonation engine

This tube is sometimes referred to as a DDT (Deflagration to Detonation Transition) tube and

its job is to force the trigger charge to burn at a rate that creates a supersonic shockwave. Once it

detonates, the small charge in the trigger chamber creates a very powerful shockwave that then

hits the main air/fuel charge in the engine's secondary combustion chamber. It may sound odd

that it is possible to compress the gas in a tube which has an open end -- but the incredible speed

of the detonation shockwave means that the air/fuel simply doesn't have a chance to be pushed

out of the tube before it is compressed. As, or because it is highly compressed, the air-fuel is

also detonated by the intense heat of the shockwave.



COMPARSION BETWEEN VARIOUS PROPULSION SYSTEMSPDE Pulsejets Turbojets Rockets

Detonation Combustion

(Pressure Rise)

Deflagration Combustion

(Pressure Loss)


(Pressure Loss)


(Pressure Loss)

Humphrey Cycle(Higher cycle

efficiency)

Bryton Cycle(Lower cycle efficiency)



Simple architecture Simple architecture Complex architecture Simple to Complex architecture

Compact Compact Bulky Bulky

Low cost to acquire, operate

Low cost High cost Low cost

Broad operating range

Subsonic Subsonic/Low Supersonic

Limiting operating range

Reusable Limited reusability Limited reusability, salt water corrosion

Limited reusability

New Technology-higher risk

Not well developed Mature Technology-high reliability

Mature Technology

Lightweight Lightweight Heavy Heavy

Few moving parts Few moving parts High-speed rotary parts

Few moving parts



FUEL INJECTION

Fuel injection is a system for admitting fuel into an engine. It

has become the primary fuel delivery system used in automotive engines, having

replaced carburetors during the 1980s and 1990s. A variety of injection systems have existed

since the earliest usage of the internal combustion engine. The primary difference between

carburetors and fuel injection is that fuel injection atomizes the fuel through a small nozzle

under high pressure, while a carburetor relies on suction created by intake air accelerated

through a Venturi tube to draw the fuel into the airstream. Modern fuel injection systems are

designed specifically for the type of fuel being used. Some systems are designed for multiple

grades of fuel (using sensors to adapt the tuning for the fuel currently used).

REQUIREMENT OF INJECTORS

Pulse detonation engine operates at certain frequency 8Hz.

T total=T Fill+T Ignition+T Purge. Filling of fuel+air mixture einning consumtion is very short in

millisecond. For better performance a reliable ignition and less ignition delay we required

gasous type air fuel mixture. But when liquid fuel is used, very fine atomization is required to

that mixture of air & fuel. This can be achieved by using appropriate fuel injector. They are as

straight orifice, air assist, air blast, swirl injector.

Swirl injectors operate at relatively high pressures (4-12 MPa)

and their design enhances atomization as well as turbulence levels in the combustion chamber

for a more efficient combustion process. Instead of the round jet solid-cone structure common to

diesel injectors, the Swirl injector produces a hollow-cone spray structure by providing a swirl

rotational motion to the fuel inside the injector. Fuel injection’s critical component is fuel

injectors



SWIRL INJECTOR

INTRODUCTION

Swirl injectors are used in liquid rocket, gas turbine, and diesel engines to improve atomization

and mixing efficiency. The circumferential velocity component is first generated as the

propellant enters through helical or tangential inlets producing a thin, swirling liquid sheet. A

gas-filled hollow core is then formed along the centerline inside the injector due to centrifugal

force of the liquid sheet. Because of the presence of the gas core, the discharge coefficient is

generally low. In swirl injector, the spray cone angle is controlled by the ratio of the

circumferential velocity to the axial velocity and is generally wide compared with non-swirl

injectors.

The basic internal geometry of the pressure swirl

injector consists of a main cylindrical body called the swirl chamber. At, or near, the upstream

end of the swirl chamber (the closed end or 'top' face) are attached the inlets. The inlets are one

or more cylindrical or rectangular channels positioned tangentially to the swirl chamber. At the

opposite end of the swirl chamber, the 'open' end, there is a conical convergence. Toward the

apex end of the cone there is a cylindrical outlet, concentric with the swirl chamber.



Swirl injectors

In this, we are going to design Swirl Injector as per our requirements for 8Hz

and 25Hz. This injector is design on the basis of mass flow rate (M fuel) of fluid through 4

injectors. To calculate the mass flow rate we need to calculate volume, area, etc. of the tube.

After the calculation we have to design swirl injector. For designing swirl injector, we need to

calculate lengths and diameters of various parts of swirl injector ( like orifice diameter and

length, swirller length and diameter etc).

Swirler

The swirlers used to impart rotation to the airflows were of particular importance. In order to

obtain a symmetrical flow, swirlers must be machined to within very tight tolerances. Swirl

vanes may be flat, or they may be curved in a variety of ways. No matter what the type of

swirler used, however, it is essential to machine the assembly very precisely. The types of

machining operations available to produce swirlers are somewhat limited, and, if the swirlers are

assembled from separate part, the difficulty of assembling them correctly increases dramatically.

For this investigation, twisted-vane swirlers were employed, as these are compact, can be

inserted directly into an air duct, and can be machined from a single piece of stock, without any

further assembly steps. In order to machine twisted-vane swirlers, aluminum blanks were first

turned down to the precise diameters required. The blanks were initially simple cylinders, with

sections cut to two diameters: one that let them fit tightly into sleeve for the next step in the

machining process, and one that matched t +3.602he required final diameter of the swirler. The

centers of the blanks were then bored out to the required inner diameter necessary for each

swirler. A special rotating assembly, attached to a precision stepper motor, was then attached to

a vertical milling machine.



The most important characteristic of any swirler is

actually the outer blade angle, for the simple reason that centrifugal effects force rotating flows

outward, and the swirl properties imparted to most of the air will depend on the properties of the

swirl vanes near the outer wall of the duct. In a flat-vane swirl assembly, the local blade angle is

a constant, and does not vary with radial location. In a twisted-vane assembly, the local blade

angle, defined as the angle between the plane of the blade and the central axis of the assembly,

varies with radial location, r, due to the twisted geometry. What is clear, however, is that swirl

can be imparted very efficiently to a flow, at very small pressure drops, if these swirlers are

employed.

Internal flow of swirler The air-core is usually seen to initiate from the outlet

orifice, where the pressure is already ambient, as one gradually increases the injection pressure.

From some observations the air-core is also seen to initiate simultaneously from the upstream

face of the swirl chamber. Thus the two ends of the air-core along the axis are not initially

joined.

The initiation of the air-core at the upstream end of the

swirl chamber is likely to be due to one or more of the following mechanisms. Firstly, as the

liquid, initially under pressure, enters the swirl chamber, then dissolved gases within the liquid

come out of suspension and are buoyed inwards toward the low pressure region on the swirl

chamber axis. Secondly, there may be an intermittent seepage of the ambient gas from the outlet

along the axis to the back face, possibly in the form of small bubbles. Figure below is a diagram

showing the air-core formation for an atomizer with a short swirl chamber and a negligible

length outlet. There is seen to be no air-core formation initiating from the upstream face in this

instance. The presence of an air-core ensures that the body of liquid within the nozzle is in the

form of an annulus and that the passage of a liquid particle through the nozzle will thus describe

a helical path.

Development of the air-core in a swirl atomizer nozzle



.

Liquid particle trajectory

Advantage of swirl injectors

Swirl injectors operate at relatively high pressures (4-12 MPa) and their design enhances

atomization as well as turbulence levels in the combustion chamber for a more efficient

combustion process. Instead of the round jet solid-cone structure common to diesel injectors, the

Swirl injector produces a hollow-cone spray structure by providing a swirl rotational motion to

the fuel inside the injector. The key advantage of hollow cone sprays is the high area to volume

ratio, which can lead to the required level of atomization without large penetration lengths. Swirl

injectors are used in liquid rocket, gas turbine, and diesel engines to improve atomization and

mixing efficiency. The circumferential velocity component is first generated as the propellant

enters through helical or tangential inlets producing a thin, swirling liquid sheet. A gas-filled

hollow core is then formed along the centerline inside the injector due to centrifugal force of the

liquid sheet. Because of the presence of the gas core, the discharge coefficient is generally low.

In swirl injector, the spray cone angle is controlled by the ratio of the circumferential velocity to

the axial velocity and is generally wide compared with non-swirl injectors.

Pulsating Flow with Swirl Injectors

The spray and acoustic characteristics of a gas/liquid swirl coaxial injector are studied

experimentally. Self-pulsation is defined as a pressure and flow rate oscillations by a time-

delayed feedback between liquid and gas phase. Self-pulsation accompanies very intensive

scream and this strong scream affects atomization and mixing processes. So, the spray and

acoustic characteristics of self-pulsation are different from those of general swirl coaxial spray.

The liquid and gas velocity is selected as the variables of injection conditions and recess length

is chosen as the variable of geometric conditions. By shadow photography technique, spray

patterns are observed in order to investigate the macroscopic spray characteristics and determine

the onset of self-pulsation. For acoustic characteristics, a PULSE System was used. Using He-



Ne laser and photo detector system frequencies of spray oscillations are measured. And self-

pulsation boundary with injection conditions and recess length is obtained. From the

experimental results, the increase of recess length leads to the rapid increase of the sound

pressure level. And characteristic frequency is mainly dependent on the liquid velocity and

linearly proportional to the liquid velocity. The frequency of spray oscillation is the same as that

of the acoustic fields by self-pulsation.

Pulsating flow with swirl injector

SPRAY FORMATION30



INRODUCTION

Sprays are an important constituent of many natural and technological processes and range in

scale from the very large dimensions of the global air-sea interaction and the dynamics of

spillways and plunge pools to the smaller dimensions of fuel injection and ink jet systems. In

general, sprays are formed when the interface between a liquid and a gas becomes deformed and

droplets of liquid are generated. These then migrate out into the body of the gas. Sometimes the

gas plays a negligible role in the kinematics and dynamics of the droplet formation process; this

simplifies the analyses of the phenomena. In other circumstances the gasdynamic forces

generated can play an important role. This tends to occur when the relative velocity between the

gas and the liquid becomes large as is the case, for example, with hurricane-generated ocean

spray.

In many important technological processes, sprays are formed by the breakup of a liquid jet

injected into a gaseous atmosphere. One of the most important of these, is fuel injection in

power plants, aircraft and automobile engines and here the character of the spray formed is

critical not only for performance but also for pollution control. Consequently much effort has

gone into the design of the nozzles (and therefore the jets) that produce sprays with desirable

characteristics. Atomizing nozzles are those that produce particularly fine sprays.

a) Spray formation

Combustion of liquid fuels differs from the combustion of gaseous fules in that a liquid fuel

must be vaporized and then combusted .This additional step adds a significant complication to

the combustion process.In the analysis of gaseous fuel combustion systems ,we were concerned



about the energy density of the fuel,the reaction rate ,the heat release rate ,the flame temperature

and the flame speed –all of which are coupled together .In the analysis of the liquid fuel

combustion systems ,we are again concerned about the energy density of the fuel ,the reaction

rate ,the heat release rate,the flame tempersature and the flame speed ;but the rate controlling

phenomenon is the evaporation of the fuel. Spray can be formed in a number of ways .Most

commonly liquid fuel spray are formed by pressurized jet atomization.In pressurized jet

atomization a spray is formed by pressurizing a liquid and forcing it through an orifice at a high

velocity to the surrounding air or gas.Alternatively ,air blast atomization produces a spray by

impinging a high velocity air flow on a relatively slow-moving liquid jet.

As a liquid emerges from an orifice into a gas ,the breakup

mechanism maybe visualized sequentially beginning with streching or narrowing of the liquid

followed by the apperence of ripples ,protuberances and ligaments in the liquid ,which leads to

the raptd collapse of the liquid into droplets.further breakup then occurs due to the vibration and

shear of the droplets and finally some agglomeration of the droplets occurs due to the collisions

if the spray is not dilute .

The spray formation process is characterized by the three dimensionless groups.These are

Jet Reynold Number (the ratio of inertia force to viscous force )

Re = ρVdμ

Jet weber number ( the ratio of inertia force to surface tension force)

We = ρVdσ

Ohnesorge number ( the ratio of viscous force to surface tension force )

Oh = μ√ ρσd

Effect of swirl in a spray formation.



When swirl is induced in the liquid as it flows into an orifice ,the jet forms a wider conical sheet

and breaks up in a similar wave like manner as in a plain jet .The spray from a plain or swirl

type orifice penetrates a certain distance before coming to rest in quiescent air.the three

dimensionless numbers above are useful in formating emperical relationships for droplet

size ,spray angle and penetration .

Droplet size distributionDroplet size measurements in spray are made using various optical techniques and by

convntional methods such as cup method for meauring MMD (mass median diameter).A short

laser can be used to penetrate the spray and illuminate a high digittal camera screen.Digital

images from the camera are then transferred to a computer and particle sizing software is used to

analyze the images obtained in order to build up a distribution of diameters.

There are five different mearsurements of diameter that are commonly used to describe the

average size of a distribution of droplet in a simple way.These are :-

1.Most probable droplet diameter

2.Mean diameter

3.Area mean diameter

4.Volume mean diameter

5.Sauter mean diameter



Most probable droplet diameter is the droplet diameter with the largest fraction of

droplets.

Mean diameter(MMD)S is the average diameter of the group of droplets based on

the fraction of droplets at each diameter.

d1 ¿∑i=1

∞

d i ∆ N i

Area mean diameter (AMD) is the average diameter based on the fraction of droplets

with a given surafce area .

d2 ¿∑i=1

∞

¿¿)

Volume mean diameter (VMD) is the average diameter based on thefraction of the

droplets with given volume.

d3 ¿∑i=1

∞

¿¿)

Sauter mean diameter (SMD) is used in a number of spray models.SMD is the VMD

divided by AMD

d32 = ∑i=1

∞

( 3√d3i ∆ N i)

∑i=1

∞

¿¿¿



CALCULATION AND DESIGN PART

Calculation for 8Hz

Given data of 1 tube :-

Length of the tube, L = 1m Diameter of the tube, d = 4inchs = 96 mm

Volume of the tube, V= π4

. d2

. L

V= π4

.( 961000 )

2

.1

V = 7.239 x10−3 m3

For time calculation: -

We know that the PDE is operating at 8Hz frequency

i.e. 8 cycles in 1sec

or 1 cycle in = 1000

8

= 125 ms

1 complete cycle consists of Filling, Ignition and Purging

.. T total=T Fill+T Ignition+T Purge

100% = 60% + 30% + 10%



60% of one cycle Filling time

0.6 x 125 = 75 ms

Now,

Volume flow rate (V ) to fill the tube = Volume

Time

V=7.239 x10−3

0.075

V = 0.09652 m3/sec

We know,

Density of Fuel = 780 kg/m3

Density of Air = 1.15 kg/m3

Density of Air/Fuel mixture = 1.2257 kg/m3

Temperature = 303 K

Now,

Mass flow rate (M ) = Volume flow rate (V ) x Density of Air/Fuel mixture (ρ)

M=¿0.09652 x 1.2257 kg/sec

M = 0.11830 kg/sec

M total=M air+M fuel

By Stoichiometry Ratio, we know mixing ratio of air/fuel for combustion process, i.e. Air: Fuel = 15:1

..M air

M fuel = 15

M fuel=M air

15

M total=M air+M air

15


http://en.wikipedia.org/wiki/Rho_(letter)


M air=

Mtotal

(1+ 115 )

¿ 0.11830

(1+ 115 )

M air = 0.11085 kg/sec = 110.85 g/sec .. M fuel=¿ 7.39 g/sec

To calculate main orifice diameter (do) for swirl injector at 8Hz.

From above calculation, we find the mass flow rate (M fuel) of fuel through 4 injectors = 7.39 g/sec

Now, mass flow rate (M fuel) of fuel through 1 injector = 7.39

4 = 1.84 g/sec

Formula to be used: M fuel = Cd.A.√2

Where, Cd = Discharge Coefficient A = Area of Orifice ΔP = Pressure difference = Density of fluid

Given: -

Cd = 0.28-0.30 ΔP = 3 to 4 bar = 780 kg/m3

A =?

Area (A) to be calculated:

A = M f

Cd .√2

= 0.00184

0.28 x√2x 3x 105 x 780


https://www.google.co.in/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0CB0QFjAA&url=http%3A%2F%2Fen.wikipedia.org%2Fwiki%2F%25CE%2594P&ei=zGrjVJrvGYWLuATro4LIBg&usg=AFQjCNF4qnxdWuUjiTdfJ__zJCzEr0TTeQ&bvm=bv.85970519,d.c2E



A = 3.0376 x10−7 m2

.. A = π4

. do2

do = 0.621 mm

Design calculation

1st Rule :-

Ds

do = 3.3

Where, Ds=Diameter of Swirl do= Diameter of Orifice

Ds= 3.3 do

= 3.3 x 0.621 Diameter of Swirl, Ds = 2.0493 mm

2nd Rule :-

Ls

Ds = 2.75

Where, Ls = Length of Swirl Ds= Diameter of Swirl Ls = 2.75Ds

= 2.75 x 2.0493 Length of Swirl, Ls = 5.635 mm



3rd Rule :-

lo

do = 0.5

Where, lo = Length of main Orifice do = Diameter of Orifice

lo = 0.5do

= 0.5 x 0.621 Length of Orifice, lo = 0.3105 mm But it is not feasible as per manufacturing point of view. So, Length of Orifice, lo ≈ 2 mm



4th Rule :-

LP

DP = 1.5

LP = 1.5 DP ………(1)

we also know that, Area of swirler , Ap=LP x DP

Using (1), we get Ap = 1.5 DP x DP ……….(2)

And

Cd=0.35( AP

Ds do)

0.5

.( Ds

do)

0.25

Given: - Discharge Coefficient, Cd = 0.28-0.30 Diameter of Swirl, Ds = 2.172 Diameter of Orifice, do = 0.658

.. AP = 0.448 mm2

By putting this value of , AP in (2) we get

DP = 0.546 mm

LP = 1.5 DP

LP = 1.5 x 0.546

LP = 0.298 mm



Calculation for 25Hz


Lenghth of the tube, L = 1m Diameter of the tube, d = 4inchs = 96 mm


. d2

. L

V= π4

.( 961000 )

2

.1

V = 7.23 x10−3 m3

For time calculation:-

We know that the PDE is operating at 25Hz frequency



i.e 25 cycles in 1sec


= 40 ms

1complete cycle consists of Filling, Ignition and Purging


100% = 60% + 30% + 10%


0.6 x 40 = 24 ms

Now,


Time

V=7023 x10−3

0.024

V = 0.3012 m3/sec

We know,




Temperature = 303 K

Now,42




M=¿0.3012 x 1.2257 kg/sec

M = 0.3692 kg/sec



..M air

M fuel = 15

M fuel=M air

15

M total=M air+M air

15

M air=

Mtotal

(1+ 115 )

¿ 0.3692

(1+ 115 )





4 = 5.767 g/sec






Area(A) to be calculated:

A = M f

Cd .√2

= 0.005767

0.28 x√2x 3 x 105 x 780 A = 9.520 x10−7 m2

.. A = π4

. do2

do = √ 4 x 9.520x 10−7

3.142

do = 1.10 mm

Design calculation

1st Rule :-

Ds

do = 3.3


Ds= 3.3 do





2nd Rule :-

Ls

Ds = 2.75



3rd Rule :-

lo

do = 0.5


lo = 0.5do

= 0.5 x 1.10 Length of Orifice, lo = 0.55 mm

But it is not feasible as per manufacturing point of view. So,



Length of Orifice, lo ≈ 2 mm

4th Rule :-

LP

DP = 1.5

LP = 1.5 DP ………(1)

we also know that, Area of swirler, Ap=LP x DP Using (1), we get Ap = 1.5 DP x DP ……….(2)

And

Cd=0.35( AP

Ds do)

0.5

.( Ds

do)

0.25

Given:- Discharge Coefficient, Cd = 0.28-0.30 Diameter of Swirl, Ds = 3.63 Diameter of Orifice, do = 1.10

.. AP = 1.407 mm2




DP = 0.968 mm

LP = 1.5 DP

LP = 1.5 x 0.968

LP = 1.452 mm.

Calculation for 50 Hz


Lenghth of the tube, L = 1m Diameter of the tube, d = 4inchs = 96 mm


. d2

. L

V= π4

.( 961000 )

2

.1



V = 7.23 x10−3 m3

For time calculation:-

We know that the PDE is operating at 50 Hz frequency

i.e 50 cycles in 1sec


= 20 ms

1complete cycle consists of Filling, Ignition and Purging


100% = 60% + 30% + 10%


0.6 x 20 = 12 ms

Now,


Time

V=7.23 x10−3

0.012

V = 0.6025 m3/sec

We know,




Temperature = 303 K

Now,48




M=¿0.6025 x 1.2257 kg/sec

M = 0.7384 kg/sec



..M air

M fuel = 15

M fuel=M air

15

M total=M air+M air

15

M air=

Mtotal

(1+ 115 )

¿ 0.7384

(1+ 115 )





4




= 11.53 g/sec



Given:- Cd = 0.28-0.30 ΔP = 3 to 4 bar = 780 kg/m3

A = ?

Area(A) to be calculated:

A = M f

Cd .√2

= 11.53

0.28 x√2x 3 x 105 x 780 x1000 A = 19.03x10−7 m2

.. A = π4

. do2

do = 1.55 mm

Design calculation

1st Rule :-





Ds

do = 3.3


Ds= 3.3 do


2nd Rule :-

Ls

Ds = 2.75



3rd Rule :-

lo

do = 0.5




lo = 0.5do

= 0.5 x 1.55 Length of Orifice, lo = 0.775 mm

But it is not feasible as per manufacturing point of view. So, Length of Orifice, lo ≈ 2 mm

4th Rule :-

LP

DP = 1.5

LP = 1.5 DP ………(1)

we also know that, Area of swirler, Ap=LP x DP

Using (1), we get Ap = 1.5 DP x DP ……….(2)

And



Cd=0.35( AP

Ds do)

0.5

.( Ds

do)

0.25

Given:- Discharge Coefficient, Cd = 0.28-0.30 Diameter of Swirl, Ds = 3.795 Diameter of Orifice, do = 1.55

.. AP = 2.028 mm2


DP = 1.162 mm

LP = 1.5 DP

LP = 1.5 x 1.162

LP = 1.74 mm.



HELIX ANGLE FOR SWIRLER

Helix angle: - Helix angle is the angle between any helix and an axial line on its right, circular

cylinder or cone.

FORMULA :-

tan∅= P X Nπ X D ∅ = HELIX ANGLE

∅=tan−1(¿ P X Nπ X D

)¿ P = PITCH

∅=tan−1( Lπ X D ¿)¿ N = No.Of STARTS

D = PITCH DIAMETER

Also,

rm=meanradius of screw thread

l = lead of the screw thread



Calculations :-

1. For 8 Hz :- Given

Pitch (length of swirler ) = 5.635 mm

Pitch diameter = 2.0493 mm

N = 2

Helix angle (∅ )=¿ tan−1( 5.635 X 23.142 X 2.0493

)

= 60.26°

2. For 25 Hz :- Given



N = 4


)

= 74.05°

3. For 50Hz :- :- Given



N = 4


)

= 74.05°



Observations :-

S.No.

DESIGNPARAMETERS

8Hz 25Hz 50 Hz

1. Diameter of Orifice, do

0.621 1.10 1.55

2. Swirl Diameter, Ds

Ds

do = 3.3

Ds= 2.0493 mm

Ds

do = 3.3

Ds= 3.63 mm

Ds

do = 3.3

Ds= 5.115 mm

3. Swirler Length, Ls

Ls

Ds = 2.75

Ls= 5.635 mm

Ls

Ds = 2.75

Ls= 9.982 mm

Ls

Ds = 2.75

Ls=14.06 mm 4. Main

Orifice Length, lo

lo

do = 0.5

lo ≈ 2 mm (assumed)

lo

do = 0.5

lo ≈ 2 mm (assumed )

lo

do = 0.5

lo ≈ 2 mm (assumed ) 5. Area of

Swirler part, AP

Cd=0.35( AP

Ds do)

0.5

.( Ds

do)

0.25

AP = 0.448 mm2

Cd=0.35( AP

Ds do)

0.5

.( Ds

do)

0.25

AP = 1.407 mm2

Cd=0.35( AP

Ds do)

0.5

.( Ds

do)

0.25

AP =2.028 mm2

6. Length of Swirler part, LP

LP

DP = 1.5

LP = 0.819 mm

LP

DP = 1.5

LP = 1.452 mm

LP

DP = 1.5

LP = 1.74 mm 7. Diameter of

Swirler part, DP

LP

DP = 1.5

DP= 0.546 mm

LP

DP = 1.5

DP= 0.968 mm

LP

DP = 1.5

DP= 1.162 mm


S.No. Input Parameters 8 Hz 25 Hz 50 Hz 1. Mass flow rate of fuel through

4 injector, (M fuel) 7.39 g/sec 23.07 g/sec 46.15 g/sec

2. Mass flow rate of fuel through 1 injector, (M fuel)

1.84 g/sec 5.767 g/sec 11.53 g/sec

3. Pressure, P 3 bar 3 bar 3 bar 4. Density of fluid, 780 kg/m3 780 kg/m3 780 kg/m3 5. Density of air 1.5 kg/m3 1.5 kg/m3 1.5 kg/m3

6. Density of mixture 1.2257 kg/m3 1.2257 kg/m3 1.2257 kg/m3

7. Discharge Coefficient,Cd (assume)

0.28 0.28 0.28

8. Area, A (m2) 3.0376 x10−7 m2 9.520 x10−7 m2 19.03 x10−7 m2


Solid work Model of Swirl Injector

From the above observation and calculations, we have got the dimensions and

measurements of Swirl Injectors and hence further we can draw the components of

Swirl Injector .

1.

(a) Injector body (solid model)

(b) Injector Body (fabricated part)



2.

(a) Holder (solid model)

(b) Holder (fabricated part)



3.

(a) Adaptor (solid model)

(b) Adapter (fabricated part)



4.

(a) Swirler (solid model)

(b) Swirler ( fabricated part)



ASSEMBLY PARTS OF SWIRL INJECTOR


INJECTOR BODYSWIRLERHOLDERADAPTOR

SWIRL INJECTOR ALONGWITH CONNECTOR


EXPERIMENTAL SET-UP FOR SWIRL INJECTOR

For determining various parameters related to swirl injector ,I have dseigned an experimental set

up for it.The parameters such as mass median diameter (MMD) of the spray,spray cone angle

and mixing of the inline swirl injectors.

SET –UP

Material used :- Plywood

It consist of the following parts:-

Fuel manifold

Fuel line

Swirl injector

Cups for collection of fuel


FUEL MANIFOLD

CUPS SWIRL INJECTOR

FUEL LINE

WASTE FUEL COLLECTION AREA


OBJECTIVES OF THE SET - UP BOX

1.SPRAY PATTERN

2.CAPACITY

3.SPRAY IMPACT

4.SPRAY ANGLE

5.DROP SIZE

We have calculated spray cone angle ,drop size and spray impact.

SPRAY CONE ANGLE :- The spray angle diverges or converges with respect to the

vertical axis. As illustrated in the figure below, the spray angle tends to collapse or

diverge with increasing distance from the orifice. Spray coverage varies with spray

angle. The theoretical coverage, C, of spray patterns at various distances may be

calculated with the equation below for spray angles less than 180 degrees. The spray

angle is assumed to remain constant throughout the entire spray distance. Liquids more

viscous than water form smaller spray angles, or solid streams, depending upon nozzle

capacity, spray pressure, and viscosity. Spray angles are typically measured using

optical or mechanical methods.



Mathematical formula for spray cone angle

C = theoretical coverage

D = spray distance

θ = spray cone angle

According to our calculations ,the spray cone angle measured is 60deg.

64


SPRAY CONE ANGLE

60 DEG


PROCEDURE FOR CALCULATING MASS MEDIAN DIAMETER (MMD)

First marking has to be done on the bottom of the cups from 1 to 12.

Now weigh the empty cups.

Cup number Empty weight (gm)

1 2.84

2 2.823 2.84

4 2.825 2.83

6 2.83

7 2.818 2.80

9 2.82

10 2.79

11 2.81

12 2.80

cup arrangement in set up box



Now we have to arrange the cups under the swirl injector and collects the fuel .Again we

have to weigh the cups.

Cup number Filled weight (gm)

1 6.04

2 7.123 6.044 5.725 6.04

6 5.43

7 5.018 6.6

9 7.3

10 5.99

11 6.81

12 6.9

droplets collected in different cups



Now calculating the wieght of the fuel collected in the cups alongwith the remaining fuel

which is not collected in the cups.

Cup number

Filled weight Empty weight Collected weight(filled – empty)

1 6.04 2.84 3.22 7.12 2.82 4.33 6.04 2.84 3.24 5.72 2.82 2.95 6.04 2.83 3.26 5.43 2.83 2.67 5.01 2.81 2.28 6.6 2.80 3.89 7.3 2.82 4.510 5.99 2.79 3.211 6.81 2.81 4.012 6.9 2.80 4.1

Time duration of flow = 20 sec

Therefore average mass flow rate of of each cup is calculated by

m = collected weighttime duration

Cup number Collected weight(gm)(filled – empty)

Time duration(Sec)

Mass flow rate in each cup(g/s)

1 3.2 20 0.16

2 4.3 20 0.213 3.2 20 0.164 2.9 20 0.145 3.2 20 0.166 2.6 20 0.137 2.2 20 0.118 3.8 20 0.199 4.5 20 0.2210 3.2 20 0.1611 4.0 20 0.2012 4.1 20 0.20



Now to calculate the droplet diameter we have to use the given formula

Formula to be used: m= Cd.A.√2

Where, Cd = Discharge Coefficient A = Area of droplet ΔP = Pressure difference = Density of fluid

By putting the values we have formed a final equation in the form of mass flow rate and

diameter of droplet

d i = √m x 0.9225

Cup number Mass flow rate in each cup(g/s)

Droplet Diameter (microns)

1 0.16 392 0.21 453 0.16 394 0.14 375 0.16 396 0.13 357 0.11 328 0.19 429 0.22 4610 0.16 3911 0.20 4312 0.20 44

Now,

Mass median diameter will be the average of these droplet diamters.

MMD = ∑ of the diametersno . of cups

= 39+45+39+37+39+35+32+42+46+39+43+4412 =480

12 = 40 microns

The MMD value which is calculated by this experiment is 40 microns.but this experiment will

be performed once again to achieve the value of 10 microns with more acurate results.

68




MIXING OF THE SPRAY

From this set up box ,we can also check the proper mixing pattern of the spray .For this

mixing ,we have to intall the swirl injectors in line and fuel supply will be given.We will then

see the mixing profermance of a single spray with the adjacent sprays.

This is done because the swirl injectors are to be placed inline in the pulse detonation engine.

mixing pattern of spray

CONCLUSION69



To replace other injectors such as ( air blast ,orifice ,etc) used in the pulse detonation engine ,we

have studied the concept of swirl injector. The swirl injector will increase the atomisation of the

fuel by adding the centrifugal force of the swirler and thus inreasing the efficiency of the

engine.We have worked in a steady mode with this swirl injector but still the research is to be

done on pulsating mode ie. It has to worked on different frequencies such as 8 Hz ,25 Hz and 50

Hz.

I have stuided the basic concept of swirl injector and designed it .For testing this swirl injector I

have also designed a set up box for it in which various parameters such as spray cone

angle ,mass median daimeter (MMD) and mixing is done.Still the results are not accurate but

more research is to be done on this swirl injector for reaching the exact results.

REFERENCES

1.Kailasanath, K. “Recent Developments in the Research on Pulse Detonation Engines,” AIAA

Paper 2002-0470, AIAA 40th Aerospace Sciences Meeting, Reno, NV, 14–17 Jan. 2002.

2. Munipalli, R., Shankar V., Wilson, D.R., and Lu F.K., “Preliminary design of a pulse

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APPENDIX



PICTURES OF SET UP BOX.

Set up box fitted with manifold

Spray cone angle test

Cup arrangements for MMD
