eng. laith batarseh - philadelphia university...eng. laith batarseh introduction turbo machines used...

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Hydraulic machines

Chapter one: Introudction

Eng. Laith Batarseh

Introduction

Turbo machines used to transfer energy from or to continuous fluid flow by means

of rotating parts

Turbo machines

Work done by fluid Work done on fluid

Turbine Pump,

compressor

and fan

1.1. Basic Concepts

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Introduction

Fluid energy

Incompressible fluid

Compressible fluid

Pressure Enthalpy

Introduction

• Examples

Pelton wheel Francis turbine Kaplan turbine

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Introduction

• Examples

centrifugal pump impeller reciprocating pump

Introduction

Outlet flow

Axial

Radial

Mixed

the path of the through-flow is wholly or mainly parallel to the axis of rotation

the path of the through-flow is wholly or mainly in a plane perpendicular to the

rotation axis

the direction of the through-flow at rotor

outlet when both radial and axial velocity

components are present in significant

amounts

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Introduction

• Control Volume

Introduction

• Linear Momentum Equation

Where:

Fx is the force component in x-direction

Fpx represents the pressure force component in x-direction

Fsx represents the shear force component in x-direction

Fbx represents the body force component in x-direction

Mx is the momentum flux in x-direction = ρQVx.

1.1,,

inxoutxcvxbxsxpxx MMM

tFFFF

1.2. Free jets

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Introduction

• For steady state flow case, linear momentum equation

become

• Similar momentum equations are applicable to

other coordinate directions y and z.

2.1

,,

inxoutx

inxoutxbxsxpxx

QVQV

MMFFFF

Introduction

Free jets

Case1: jet on Stationary Plate

Assume:

1. The flow is open to atmospheric

2. No friction between fluid and plate

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Introduction

Case2: jet on Movable Plate

Introduction

Case2: jet on Movable Plate

power transmitted to the plate (P)

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Introduction

Example 1.1

Problem statement

Introduction

Example 1.1

Solution

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Introduction

Example 1.1

Solution (a)

Introduction

Example 1.1

Solution (b)

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Introduction

Example 1.2

Problem statement

Introduction

Example 1.2

Solution

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Introduction Example 1.2

Solution

Introduction

Example 1.2

Solution

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Introduction

Example 1.2

Solution

Introduction

Example 1.3

Problem statement

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Introduction

Example 1.3

Solution

Introduction

Example 1.3

Solution

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Introduction

Example 1.3

Solution

Introduction

Example 1.3

Solution

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Introduction

Case3: Jet impingement on a set of flat plates mounted on a wheel

when all the plates on the wheel are

considered, one or other vanes will

intercept all the flow from the jet. Thus,

the entire discharge issuing out of the

jet is involved in the transfer of power

to the wheel. While the relative velocity

of plates is still (V – u), the total

discharge Q (= AV) is involved in the

momentum flux undergoing the

change and not the relative discharge

Qr

Introduction

Case3: Jet impingement on a set of flat plates mounted on a wheel

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Introduction

Case4: Jet Impingement on a Stationary Curved Plate

Introduction

Case4: Jet Impingement on a Stationary Curved Plate

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Introduction

Case5:Jet Impingement on a Single Moving Symmetric Curved Plate

Introduction


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Introduction



Problem statement

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Introduction solution

Introduction solution

Study example 1.5

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Problem statement

Introduction Solution

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Introduction Solution

Introduction

Case6: Jet impingement on a Series of Curved Vanes Mounted on a Wheel

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Introduction


Introduction


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Introduction

Velocity Triangles

Introduction

1.3. Velocity Triangles

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Introduction

Other cases

1.3. Velocity Triangles

Introduction

Velocity Triangles

Mo

vin

g b

lad

e

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Introduction

Velocity Triangles

α < 90o

Introduction

Velocity Triangles

α = 90o

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Introduction

Velocity Triangles

α > 90o


Problem statement

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Solution


Solution

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Solution


Problem statement

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Solution


Solution

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Solution


Solution

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Introduction

1.7. classification of hydraulic turbines

Interaction with

water flow

Impact Reaction

No pressure change at the

rotor (i.e. jet impact occurs at

atmospheric pressure)

Examples: Pelton wheel

pressure changes at the rotor

(i.e. jet impact occurs in cased

machine)

Examples: Francis and Kaplan

turbine s

Introduction

1.7. 1classification of hydraulic turbines

Head

High head

H> 400m

Low head

3m<H<60m

Medium head

60m<H<400m

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Introduction

1.7.2. turbine Efficiencies

Introduction


1. Volumetric Eficiency, ηv

2. Hydraulic Eficiency, ηh

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Introduction


3. Mechanical Eficiency, ηm

4. Overall Eficiency, ηo

Introduction


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Introduction

1.8. similarity ratios

Introduction

1.8. 5. Similarity Ratios of Turbinebsy Dimensionanl Aalysis

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Introduction


Reynolds number

Introduction


Assume the effect Reynolds number is neglected

1.8. 6. Specific Quantities

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Introduction


Introduction


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Introduction

Introduction

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Introduction

Introduction

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Introduction

Introduction

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Introduction

Introduction

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Introduction

Introduction

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