“A STUDY REPORT ON STAR RATING OF AN AIR CONDITIONER”

An Industry Oriented Mini Project Report Submitted to

Jawaharlal Nehru Technological University, Hyderabad

In partial fulfillment of the requirementsfor the award of the degree of

BACHELOR OF TECHNOLOGY

IN

MECHANICAL ENGINEERING

ByB. MOUNIKA REDDY C. RAJ SEKHAR(09881A0310) (09881A0321)

N.SINDHU K.SRIKANTH(09881A0338) (09881A0339)

Under the guidance ofMr. N.SRINIVASA REDDY(Ph.D)

Associate Professor Department of Mechanical Engineering

DEPARTMENT OF MECHANICAL ENGINEERING

VARDHAMAN COLLEGE OF ENGINEERING(Autonomous)

(Affiliated to JNTU Hyderabad, Approved by AICTE and Accredited by NBA)Shamshabad – 501 218, Hyderabad

2012 – 2013

VARDHAMAN COLLEGE OF ENGINEERING(Autonomous)

(Affiliated to JNTU Hyderabad, Approved by AICTE and Accredited by NBA)Shamshabad – 501 218, Hyderabad

DEPARTMENT OF MECHANICAL ENGINEERING

CertificateThis is to certify that an Industry oriented mini project

work entitled ” A Study Report on Star Rating of an Air

Conditioner” is the bonafide work done By

B. MOUNIKA REDDY C. RAJ SEKHAR(09881A0310) (09881A0321)

N.SINDHU K.SRIKANTH(09881A0338) (09881A0339)

at Tecumseh Products India Private Limited, Hyderabad. is submitted to Jawaharlal Nehru Technological University, Hyderabad in partial fulfillment of the requirements for the award of B.Tech degree in Mechanical Engineering during 2012-2013.

Project Guide: Head of the Department:

Prof. N. SRINIVASA REDDY Prof. N. SRINIVASA REDDYAssociate Professor Dept of Mechanical Engineering,Dept. of Mechanical Engineering Vardhaman College of Engineering,Vardhaman College of Engineering, Hyderabad.Hyderabad.

Viva-Voce held on……………………………………………

_________________ _____________________ Internal Examiner External Examiner

DECLARATION

We hereby declare that this project report titled “A Study Report on Star Rating of

an Air Conditioner” is a genuine project work and effort carried out by us in B.Tech

(Mechanical Engineering) degree course of Jawaharlal Nehru Technology University, Hyderabad

and has not been submitted to any other course or university for the award of our degree. Where

other sources of information have been used, they have been acknowledged

Signature of the Candidate

B. MOUNIKA REDDY (09881A0310)

C. RAJ SEKHAR (09881A0321)

N.SINDHU (09881A0338)

K.SRIKANTH (09881A0339)

ACKNOWLEDGEMENT

The satisfaction that accompanies the successful completion of the task would be put

incomplete without the mention of the people who made it possible, whose constant guidance and

encouragement crown all the efforts with success.

We avail this opportunity to express our deep sense of gratitude and hearty thanks to

Mr. Aditya Vishwanathan for granting us this great opportunity to do our project in this

esteemed research facility Tecumseh Products India Pvt. Ltd. despite their own schedule

constraints.

It was impossible for us to do our project outside our college campus if our beloved

principal has not granted us the permission. We, thereby express our deep sense of gratitude and

thanks to Dr. N. Sambasiva Rao, Principal, Vardhaman College of Engineering.

We would also like to express sincere thanks to Prof. N.Srinivasa Reddy, Head,

Department of Mechanical Engineering, for his expert guidance and encouragement at various

levels of our Project.

We are thankful to our guide ___________ , Assistant Professor, for his sustained

inspiring Guidance and cooperation throughout the process of this project. His wise counsel and

suggestions were invaluable.

We cannot forget to recall, with our deepest regards, the power of blessings of our parents,

and friends which gave us the courage and confidence to materialize our dream of completing this

project.

B. MOUNIKA REDDY (09881A0310)

C. RAJ SEKHAR (09881A0321)

N.SINDHU (09881A0338)

K.SRIKANTH (09881A0339)

TABLE OF CONTENTS

Candidates Declaration i

Acknowledgement ii

Abstract iii

Nomenclature iv

List of Figures vi

List of Tables vii

List of Plots viii

Table of Contents ix

CH.NO. NAME OF THE CHAPTER PAGE NO

1. Introduction 1

2. Literature Survey 3

2.1 Aerodynamic effects of wing leading edge ice contamination 3

2.2 Leading edge bluntness effects on aerodynamic heating and

drag of power law body in low density hypersonic flow 5

3. Wind Tunnel 6

3.1 Types of wind tunnel 7

3.1.1 Open circuit subsonic wind tunnel 7

3.1.2 Closed circuit subsonic wind tunnel 8

3.2 Components of wind tunnel & their functions 9

3.3 Features and capabilities of HAL wind tunnel 10

3.4 Instrumentation 11

3.5 Wind tunnel balance

11

3.6 Wind generation system 12

3.7 Model support system

12

3.8 Transducer – strain gauge type balance 13

3.9 Signal conditioning amplifier

13

3.10 Analog to digital converters

13

3.11 Data processing computer connected to ADC 13

3.12 Data acquisition system 14

4. Models and their Design, Material & Fabrication 15

5. Boundary layer and Sensitiveness of leading edge 18

5.1 Boundary Layer 18

5.1.1 Boundary layer control

18

5.1.2 Methods of Boundary layer control

19

5.2 Sensitiveness of Leading Edge 19

6. Testing 21

7. Results and Discussions 22

8. Conclusion and Future Scope 25

9. Bibliography 26

INTRODUCTION

Right from the “Flyer-I” to the latest state-of-the-art airplanes, rotorcrafts, missiles, space

launch vehicles and other innovative aircrafts WIND TUNNELS are being used to solve the

basic aerodynamic problems. Testing newly designed aircraft in appropriate real-time weather

conditions are needed in order to properly asses its capabilities during real time flying, which is

achieved in a most accurate, rapid and economical way by using wind tunnels.

The quantum leap in computer technology in the 20th century has led to the development

of techniques such as CFD, CFX and other hi-tech simulation software for the analysis of

aerodynamic problems and generation of useful data for the design and development of

aircrafts, but still wind tunnels are considered as the most reliable source for gathering required

data and information necessary for the design of an aircraft. Hence wind tunnels need to be

calibrated to achieve this reliability.

The Wright Brothers built a wind tunnel, first a simple one and then a large and a more

sophisticated tunnel with 16x16 sq. in a test section which was successful with the addition of

rudder to counteract the adverse yaw from the wrapped wing roll control. The value of wind

tunnel in aerodynamic design was conclusively demonstrated in 1903. It is a research tool used

in aerodynamic research to study the effects of air moving past solid objects.

Wind tunnels are often the most rapid, economical and accurate means for conducting

aerodynamic research and obtaining aerodynamic data to support design decisions. The

aerodynamic characteristics of an aircraft is achieved by the force and moment measurements

using a six component strain gauge balance and the quality of these forces and moments

mainly depend on the quality of flow in test-section, instrumentation and model design and

consideration. The test section flow condition can be qualitatively seen by tufting the entire test

section and observe fluctuations or disturbances.

Aerodynamicists use wind tunnel to test the models of proposed aircrafts and engine

components. The main aerodynamic objective for most wind tunnels is to obtain a flow in the

test section that is as near as possible to a parallel steady flow with uniform speed through out

the test section. During the test, the model is placed in the test section of tunnel and air is made

to flow past the model

LITERATURE SURVEY

2.1 AERODYNAMIC EFFECTS OF WING LEADING EDGE ICE

CONTAMINATION:

The cleanliness of leading edge is very important factor for an aircraft and has a great

impact on its performance. The most significant effect of snow or ice on the wing surface is its

influence on the smooth flow of air over the surface contour. Changes in the contour shape and

roughness of the surface will cause the airflow to begin to separate from the wing at lower angle of

attack than normal and cause a reduction in the lift which will normally be developed by a wing at

a given angle of attack and a given airspeed. Both the maximum lift, which can be developed, and

the angle of attack at which it will be developed will be reduced significantly. Stall buffet and stall

will be encountered at higher than normal airspeeds.

LIFT AND DRAG EFFECTS OF WING CONTAMINATION:

Ice contamination of an aircraft wing also has a significant detrimental effect on the

aircraft’s total drag, that is, the force that resists the aircraft’s forward motion through the air. The

total drag has two components, parasite drag and induced drag. Induced drag is that drag which is

produced by the generation of the lift. Induced drag increases as the angle of attack increases.

Therefore, since a contaminated wing must fly at higher angle of attack at a given airspeed will be

higher than the induced drag of an uncontaminated wing. Furthermore, since ice contamination

causes the airflow to separate earlier from the upper surface of the wing, its results in a higher

induced drag value at any angle of attack. The increase in parasite drag as a result of ice

contamination is small in comparison to the increase in induced drag.

The leading edge portion of the wing is most sensitive to contamination. The effects of the

contamination decrease as the forward most extent of the contamination moves farther aft of the

leading edge. Glaze ice accretions, which occur at temperatures just below freezing, provide the

largest aerodynamic penalty.

Ice accumulation, in particular, the detrimental effects on lift and drag associated with wing

surface roughness has been identified as a casual factor in a number of take-off accidents involving

jet transport aircraft.

EFFECTS OF ICING ON ROLL CONTROL:

Ice on the wings forward of the ailerons can affect roll control. Wings on general aviation

aircraft are designed so that stall starts near the root of the wing and progresses outward, so the

stall does not interfere with roll control of the ailerons. However, the tips are usually thinner than

the rest of the wing, so they are the part of the wing that most efficiently collects ice. This can lead

to a partial stall of the wings at the tips, which can affect the ailerons and thus roll control. If ice

accumulates in a ridge aft of the boots but forward of the ailerons, this can affect the airflow and

interfere with proper functioning of the ailerons. If aileron function is impaired due to ice, slight

forward pressure on the elevator may help to reattach airflow to the aileron. 

WING STALL:

The wing will ordinarily stall at a lower angle of attack, and thus a higher airspeed, when

contaminated with ice. Even small amounts of ice will have an effect, and if the ice is rough, it can

be a large effect. Thus an increase in approach speed is advisable if ice remains on the wings. How

much of an increase depends on both the aircraft type and amount of ice. Stall characteristics of an

aircraft with ice-contaminated wings will be degraded, and serious roll control problems are not

unusual. The ice accretion may be asymmetric between the two wings. Also, the outer part of a

wing, which is ordinarily thinner and thus a better collector

of ice, may stall first rather than last. [7] 

2.2 LEADING EDGE BLUNTNESS EFFECTS ON AERODYNAMIC

HEATING AND DRAG OF POWER LAW BODY IN LOW DENSITY

HYPERSONIC FLOW

A numerical study is reported on power law shaped leading edge situated in a rear field

hypersonic flow. The sensitivity of the heat flux and drag coefficient to the shape variation of such

leading edge is calculated. Calculations shows that the stagnation point heating on power law

leading edge with finite radius of curvature follows the same relation for classical blunt body in

continuous flow. It scales inversely with the square root of the curvature radius at the nose. Those

leading edge with zero or infinity radii of curvature, the heat transfer behavior is in surprising

agreement with that for classical blunt body far from the nose of leading edge. [8] 

REFERENCES

1. HAL- ARDC Wind Tunnel reference material.

2. Canadian Aviation Safety Board, Majority report.

3. W. F. N. SANTOS JOURNAL, Combustion and Propulsion Laboratory,

National Institute for Space Research

4. ALAN POPE, WILLIAM H. RAE, Jr and JEWEL B. BARLOW:

“LOW SPEED WIND TUNNEL TESTING” Third ed., John Wiley and sons Inc.

New York-USA.

5. JOHN D. ANDERSON, Jr (2007) : “FUNDAMENTALS OFAERODYNAMICS” Fourth

ed., Mc Graw-Hill Inc. Singapore.

6. L. J. CLANCY (1975) : “AERODYNAMICS” First ed., Pitman Publishing Corporation.

7. A C KERMODE: “MECHANICS OF FLIGHT” Eighth ed., New Delhi

8. http://windtunnelengr.ucdavis.edu/research

UC DAVIS AERONAUTICAL WIND TUNNEL FACILITY,

UNIVERSITY OF CALIFORNIA, CALIFORNIA, USA.