FM-K01-12

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Technische Universitt Mnchen

Prof. Dr.-Ing. H.-P. Kau Module Fluid Machinery 1 - 0

Chapter 1

1. Introduction

1. Area of application2. Classification

3. Examples

4. Reciprocating engines in comparisonwith turbomachinery

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Area of application

Turbomachines are devices in which energy is transferred between a continuously flowing fluid

and a rotor. The first part of the word turbomachine is of Latin origin and implies that which spinsaround, as does the rotating blade row, the rotor, when it converts the energy of the fluid or themechanical energy of the shaft. The working fluid flowing through the turbomachinery can be of liquidor of gaseous type or even be a multiphase flow suchas insteamturbines.

Water turbines in power plants

Compressors or turbines in turbochargers orgas turbines

Machinery for chemical processes

Steam turbines in power plants

Wind turbines

Circulation pumps for heating systems indomestic homes

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Flow of energy in turbomachinery

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Classification of turbomachinery (1)

Source:Bohl,S

trmungsmaschinen1

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Compressibility offluid

Compressible (thermal turbomachine) Incompressible (hydraulic turbomachine)

Direction of energytransfer

Rotor >> Fluid,driven TM

Fluid >> Rotor,driving TM

Rotor >> Fluid,driven TM

Fluid >> Rotor,driving TM

Examples Compressor Steam turbine Pump Water turbine

Casing

Without With casing Without With casing

Propeller Axial-flowcompressor

Diagonalcompressor

Centrifugalcompressor

Windturbine

Axial-flowturbine

Diagonalturbine

Radialturbine

Workingflow

Axial Axial Diagonal Radial Axial Axial Diagonal Radial

In direction of the flow (arrow):pressure increase, decrease of specific volume,

decreasing cross-section

In direction of the flow (arrow):pressure decrease, increase of specific volume,

enlarging cross-section


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Characteristic Classification Example Criterion

Singlestage

Multistage

Singlesuction

Doublesuction

Numberof

stages

Numberof

suction

channels

Positive/negativeworkneededis

notaccomplishedbyonestage

Moreflowthanasinglesuction

constructioncansupplyisneeded

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Examples of centrifugal pump design (incompressible fluid)

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Construction Differentiation Criterion

Casing design Single-walled Double-walledRelief of the inner casing improves its circularity andtherefore the tip clearance is not affected as much.

Casing splittingAxially split

casing

Radially split

casing

Radiallysplit casings have a better circularity andshould be preferred when dealing with highpressures.

Number of shafts One shaftMultiple number

of shaftsImproves stage design matching

Shaft position Horizontal Vertical Vertical is preferred in big hydraulic turbomachines.

Reversibility of flowdirection

Not reversible ReversibleE.g. reversibility in pumped-storage hydroelectricpower plants

Further classification possibilities

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Single-stage compressor (DEMAG)

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Axial-flow compressor with radial output stage

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Turbocharger 3K-Warner

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KSB Omega Double-suction radial flow pump

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Impulse turbine (Pelton wheel)

Pelton wheel:

Head range: 100 2000 mPower output: 0,08 400MW

Source:W.

Bohl,S

trmungsmaschinenI

Source:Fa.Lingenhle

Wheel of a Pelton turbine Six-jet Pelton turbine

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Francis turbine:Head range: 10 900 mPower output: 0,03 - 500MWRadial inlet flowVariable guidevaneAxial outlet flow

Inlet

Adjustment cylinder

Turbine shaft

Turbine guide bearing

Guide vane adjusting mechanism

Runner

Outlet

Inlet scroll

Pressure control valve

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Axial and radial cross section of a Francis turbine

Turbine shaft

Guide vanes Runner

Guide vane adjusting

mechanism

Inlet scroll

Inlet

Spiral casing

Fluid

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Kaplan turbine (1)

Kaplan turbines:

Head range: 5 80 m(hydropower plants)

Power output: ca. 0,1 150 MW

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Kaplan turbine (2)

Source:W.

Bohl,S

trmungsmaschinenI

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Industrial gas turbine: Siemens V94

Performance Data (V94.3A):Power Output: 265 MWEfficiency: 38,5 %

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Comparison: Reciprocating engine Turbomachinery (1)

Reciprocating engines and turbomachinery compete in many areas of use:

For a given set of operating requirements there is usually one type of compressor/pump or turbinebest suited for the operation.

When dealing with high flow rates, low pressure ratios and a high demand for energyturbomachinery is preferred,

whereas when dealing with low flow rates, high pressure ratios and a low demand for energyreciprocating machines are usually opted for.

Reciprocating engine Turbomachinery

Movement of fluid Interrupted Continous process

Compression of gas high low

Engine Intermittent internalcombustion engine

Gas turbine, steamturbinewind-/water turbines

Load transmission Hydraulic pistons Hydraulic coupling

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Reciprocating

engine

Turbomachinery

Principle of operation

Max. speed ~ 20.000 rpm ~ 100.000 rpm

Pressure ratio high low

Flow rate low high

Type of Flow intermittent continuous

Maintenance costs high low

AW FF

AbFA

Flow principle

ApF

Displacementdevice principle

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A big advantage of a gas turbine is its weight and the little space it requires:

MTU 16V 595 TE70L MTU TF50

Power output (kW) 3925 3805Rotational speed (rev/min) 1750 1070

Length (m) 3,98 1,395

Width (m) 1,66 0,89

Height (m) 2,87 1,04

Volume (m3) 18,96 1,29

Weight (kg) 13000 710

Although having the same power output as the reciprocating engine the gas turbine only

requires 7% of the space and weighs 5,5% as much.

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FM-K01-12