SCG2015 CFturbo Mueller

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Several Examples of Turbomachinery

Design and CFD-Simulation usingCFturbo® and STAR CCM+®

Dipl.-Ing. Ralph Peter Mueller

CFturbo Software & Engineering GmbH

Munich, Germany


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www.cfturbo.com

Several Examples of Turbomachinery Design and CFD-Simulation

using CFturbo® and STAR CCM+

CFturbo® Software & Engineering GmbH

Engineering CAD & Prototyping

• Turbomachinery

Conceptual Design

• CFD/FEA Simulation

• Optimization

• 3D-CAD Modeling

• Prototyping

• Testing, Validation

CFturbo® Software

• Turbomachinery

Design Software

• Automated

Workflows

Company


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www.cfturbo.com



Conceptual

Design

CFturbo®

Meshing, CFD-Simulation, Post-Processing

STAR CCM+

3D-CAD

CATIA, Creo, UG NX,SolidWorks, SpaceClaim, …

ProductionComputation, optimization:

interactively or automated

Experiments

Prototyping, Testing,Validation, …

Turbomachinery Design Process


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www.cfturbo.com



Manual „Optimization“ Workflow

Transsonic Radial CompressorTraditional common workflow: 5 … 25 model variations, 1 to 4 weeks,

Design point (BEP)

Total pressure ratio: ∏tt = 4

Mass flow rate: ṁ = 0.11 kg/s

Speed: n = 90.000 min-1

Power (limitation): Pm < 30 kW

20 Designs 20 Performance Curves 1 Prototype


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CFturbo Model Overview

Pumps


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Compressors, Turbines






Fans, Blowers





Example 1. Radial Pump with Inducer

Comments- Generic CFturbo design, 5 design variations

- Q=600 m³/h,P=120 bar, n=12000 rpm

- Compare CFD-simulation

• Steady State, no cavitation

• Transient flow, no cavitation

• Transient flow, with cavitation

- No experimental are data available






0.2

0.4

0.6

0.8

1

1.2

1.4

0.4 0.6 0.8 1 1.2 1.4 1.6

H e a d

/ H e

a d

D e s i g n

P o i n t

Flow Rate / Flow Rate Design Point

steady state w/o cavitation

transient w/o cavitation

transient w/ cavitation

Design Point





,


Volume Flow, Vapor Fraction

,

H e a d P r e s s u r e

• Rising vapor fraction determines lower pressure

• Transient flow simuation with cavitation modeling is

essential for NPSH calculations


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Example 2. Initial Design Axial Pump

Leading edge blade tip cavitation


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0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

400 600 800 1000 1200 1400 1600 1800 2000 2200 2400

e f f i c i e n c

y [ -

]

MassFlow [kg/s]

transient stady state transient with Cavitation model

Very first initial design >> hydraulic efficiencyshould be significantly improved





Example 3. Radial Blower

Comments- Customer design

- CFD-Solver-Benchmark

- Steady state (MFR) and transient flow

- Coarse mesh (approx. 1 Mio. nodes)

- Experimental data available






Comments- Customer design

- CFD-Solver-Benchmark

- Steady state (MFR) and transient flow

- Coarse mesh (approx. 1 Mio. nodes)

- Experimental data available


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0

500

1000

1500

2000

2500

3000

3500

0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.16 0.18 0.20

S t a t i c P r e s s u r e D i f f e r e n c e [ P a ]

Q [m^3/s]

dp_InOut CCM+

dp_InOut CCM+ (transient)

dp_InOut Solver I

dp_InOut Solver II

dp_InOut Messung


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0

500

1000

1500

2000

2500

3000

3500

0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18 0.2

S t a t i c P r e s s u r e D i f f e r e n c e [ P a ]

Q [m^3/s]

dp_InOut Solver Mean

dp_InOut Solver Max

dp_InOut Solver Min

dp_InOut Messung



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0

100

200

300

400

500

600

0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.16 0.18 0.20

P o w e r P I [ W ]

Q [m^3/s]

PI CCM+

PI CCM+ (transient)

PI Solver I

PI Solver II

P Messung


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0

100

200

300

400

500

600

0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18 0.2

P o w e r P I [ W ]

Q [m^3/s]

PI Mean Solver

PI Max Solver

PI Min Solver

P Messung


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0.0000

0.1000

0.2000

0.3000

0.4000

0.5000

0.6000

0.7000

0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.16 0.18 0.20

E f f i c i e n c y [ - ]

Q [m^3/s]

eta_InOut CCM+

eta_InOut CCM+ (transient)

eta_InOut Solver I

eta_InOut Solver II

eta_InOut Messung


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Example 3.

Radial Blower

0.000

0.100

0.200

0.300

0.400

0.500

0.600

0.700

0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18 0.2

E f f i c i e n c y [ - ]

Q [m^3/s]

eta_InOut Solver Mean

eta_InOut Solver Max

eta_InOut Solver Min

eta_InOut Messung

Reasons of discrepancy between simulation and measurement

should be investigated - mesh, time step, turbulence models,…

- check experimental set-up


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Example 4. Virtual Automotive Cooling Fan Test Rig

Downstream channel

with or w/o blockage

Heat

Exchanger

Impeller

Stator

- Customers supplier design- CFturbo impeller re-design

- Performance curve simulations, Steady state

(MFR) + transient flow on a virtual testbench

- Scientific investigation on downstream flow

patterns and performance curves

- A challenge: PACKAGING


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Mixing Plane (Stage Inteface)

Mean values of pressure and momentum

are used to provide radial distribution

Frozen Rotor

1:1 direct transfer of all physical values

to the other side of the interface

Are these steady state models a good alternatives compared to transient

simulation of axial automotive cooling fans?


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S t a t i c P r e

s s u r e D i f f e r e n c e

[ P

a ]

Transient

Mixing Plane (MP)

Frozen Rotor (FR)

Steady state CFD-solutions aredependent on the position of

the Rotor-Stator-Interfaces!

>> Computation of energy

transmission within the

impeller is affected!

Volume flow Q/Q ref

Performance Curves



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Frozen Rotor

Transient

Mixing Plane



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Summary

CFturbo® and STAR CCM+ is a powerful combination for conceptual Turbomachinerydesign and 3D-CFD-simulation

For different Turbomachinery applications different methodologies may be necessary

Transient simulations do provide more accurate results im most cases

Automated workflows and multi-objective optimization processes are available by

additional application of OPTIMATETM and HEEDSTM

Various types of Turbomachinery can be designed and investigated effectively

• pumps, blowers, compressors, turbines• radial, mixed-flow and axial type

• incompressible and compressible flow

• without and with cavitation

Documents

SCG2015 CFturbo Mueller