DESIGN AND ANALYSIS OF A CENTRIFUGAL COMPRESSOR...

DESIGN AND ANALYSIS OF A

CENTRIFUGAL COMPRESSOR FOR A

SIMPLE CYCLE GAS TURBINE ENGINE

Elkin Gutiérrez

Grupo de Estudos em Tecnologias de

Conversão de Energia - GETEC

OUTLINE OF PRESENTATION

• Group presentation

• Introduction

• Objectives

• Compressor design

• CFD simulation

• Conclusions

• Acknowledgments

ABOUT US

• The Study Group on Energy Conversion Technologies –

GETEC of Federal University of Itajubá – UNIFEI, was

created in 2009.

• In the area of energy conversion, GETEC has experience in

analysis and simulation of gas turbine cycles, and CFD

simulations of compressors, turbines, combustion chambers

and compact heat exchangers recuperators, as well as

laboratory experiments.

• GETEC offers training courses in gas turbines engine,

centrifugal and reciprocating compressors, internal

combustion engines, among others.

INTRODUCTION

• Solutions to present and future energy shortages will rely

increasingly on improved designs of high-efficiency turbo

machinery.

• Centrifugal compressors are used in a wide range of

applications in which performance and mechanical integrity

are invariably among the paramount design objectives.

OBJECTIVE

• This work presents the validation and results of a one-

dimensional code for the design of a centrifugal

compressor impeller as a tool for very fast and reliable

preliminary results

PRELIMINAR CYCLE

SIMULATION

Compressor design

ENGINE DESIGN POINT SELECTION

Parameter Value Units

Ambient temperature 288 K

Ambient pressure 101.32 kPa

Turbine inlet temperature 1123 K

Fuel temperature 288 K

Pressure ratio 4 --

Compressor adiabatic efficiency 80 %

Combustion adiabatic efficiency 99 %

Turbine efficiency 85 %

Gas turbine power output 600 kW

THERMAL PERFORMANCE ANALYSIS

Stream Temperature Pressure Flow

S1 288 101.3 4.29

S2 461 405.3 4.29

S3 288 500.0 0.07

S4 1123 397.2 4.4

S5 846 101.3 4.4

ONE DIMENSIONAL CODE

Compressor design

CODE INPUT DATA

.m .m

NON-DIMENSIONAL PARAMETERS

Parameter Equation

Incidence

factor

Impeller Speed

Flow

Coefficient

Parameter Equation

Mass Flow

Parameter

Blade Loading

Coefficient

Specific

Speed

Power

Coefficient

2 21 tan / tan

1/21

2

01

( ) 1

( 1)

k

k

s

U PR

a k

2

21 011 1

01 2 01 2

(1 )sr aC

r a U

1

2

3

4

2

sN

2

01

2.

a

UW ND

2

01

U

a

2 s

ONE-DIMENSIONAL CODE OUTPUT DATA

CODE VALIDATION

Compressor design

VALIDATION RESULTS

Parameter Experimental* Code Dev [%]

Hub Radius 35.4 35.5 0.28

Shroud Radius 91.7 92.0 0.36

Exit Radius 200.0 200.9 0.44

Rotation [rpm] 22360 22839 2.14

Exit Absolute Mach 0.96 0.92 3.89

Tangential Velocity 468.3 480.5 2.60

* Krain H. Test Case 2: Centrifugal Impeller, DLR. In: Group ETS, editor. Seminar

and Workshop on 3D Turbomachinery Prediction II. Val d’Isère, France; 1994.

CFD SIMULATION

Compressor design

CFD GEOMETRY


Shroud radius 95.25 mm

Hub radius 26.67 mm

Inlet area 26270 mm2

Discharge radius 190.51 mm

Blade height 10.84 mm

Axial length 95.25 mm

Discharge area 12970 mm2

Blades number 20 ----


Inlet radius 209.56 mm

Discharge area 14270 mm2

Discharge radius 282.90 mm

Blade length 143.00 mm

Blade spacing 93.55 mm

Blades number 19 ----

ASSEMBLE IMPELLER-DIFFUSER

MESH CHARACTERISTICS

Domain Nodes Elements

Impeller - R1 79 552 69 800

Diffuser - S1 103 114 92 244

Both Domains 182 666 162 044

BOUNDARY PARAMETERS

Inlet

Domain R1

Flow regime Subsonic

Heat transfer Stat. frame total temperature (288 K)

Mass and momentum Stat. Frame Total Pressure (101.32 kPa)

Turbulence: Eddy Viscosity Ratio

Interface

Domain interface R1 to S1

Interface type Fluid-Fluid

Frame change Stage

Mesh connection General Grid Interface

BOUNDARY PARAMETERS

Outlet

Domain S1

Flow regime Subsonic

Mass and momentum Average static pressure (274.52 kPa)

Pressure profile blend 0.05

Wall

Domain R1, S1

Location Hub, Shroud, Blade

Heat transfer Adiabatic

Mass and momentum No slip wall

Wall roughness Smooth wall

CFD RESULTS

COMPARISON RESULTS

Stage parameter CFD Code Dev [%]

Input power 780.4 752.2 3.6

TPR 4.08 4.00 2.0

TTR 1.69 1.61 4.7

i 74.58 80.00 7.3

Inlet parameter CFD Code Dev [%]

Static pressure 89.84 89.84 0.00

Total pressure 101.3 101.3 0.00

Static temperature 278.3 278.3 0.00

Total temperature 288.1 288.0 0.03

Absolute Mach 0.41 0.42 0.93

Tangential velocity 228.6 250.9 9.75

Absolute velocity 138.5 144.8 4.58

Outlet parameter CFD Code Dev [%]






Relative Mach 0.58 0.56 2.83


COMPARISON RESULTS

COMPARISON RESULTS

Outlet parameter CFD Code Dev [%]


Absolute mach 0.33 0.33 1.12

Flow angle 33.78 35.19 4.01





Mass flow rate 4.11 4.28 4.12

Inlet parameter CFD Code Dev [%]



Flow angle 26.36 24.32 8.37

COMPRESSOR CHARACTERISTIC CURVE 100% SPEED

3,4

3,5

3,6

3,7

3,8

3,9

4

4,1

4,2

4 4,1 4,2 4,3 4,4 4,5 4,6

Pre

ss

ure

Ra

tio

Mass Flow [kg/s]

Design point

CONCLUSIONS

• The developed code constitutes a practical and reliable

preliminary design tool for determining the basic

configuration of centrifugal compressors.

• Through of a one dimensional code is feasible to obtain

fairly close results, which can be optimized subsequently by

mean of more detailed CFD processes.

ACKNOWLEDGMENTS

• Petrobras Research and Development Center (CENPES)

• National Council of Technological and Scientific

Development (CNPq)

• Foundation for Research Support of Minas Gerais

(FAPEMIG)

DESIGN AND ANALYSIS OF A CENTRIFUGAL COMPRESSOR...

Documents

Transcript of DESIGN AND ANALYSIS OF A CENTRIFUGAL COMPRESSOR...