Cavitation Models : Performance and Limitations

R. Bannari, P. Proulx

Cavitation Models : Performance and Limitations

S. Cupillard, M. Page,A-M. Giroux

OutlinesOutlines

Introduction

Cavitation Models

Test Cases

Results

Conclusion and future work

Introduction

Cavitation Models

Test Cases

Results

Conclusion and future work

Introduction

Introduction

Consequences

Objectives

Increase the efficiency of turbo machinery.

Better understanding of the complex relationship betweenthe cavitation and the associated drop in performance.

The accurate prediction of thisphenomenon is essential for:

Increase the efficiency of turbo machinery.

Better understanding of the complex relationship betweenthe cavitation and the associated drop in performance.

The accurate prediction of thisphenomenon is essential for:

CavitationCavitation ModelsModels

Sauer Singhal Kunz Zwart

1e 7 / 1e 8

CavitationCavitation ModelsModels

SinghalSauer Singhal Kunz Zwart

CavitationCavitation ModelsModels

SinghalSauer Kunz Zwart

Cprod= 100Cdes=100

Cprod= 0.2Cdes=0.2

Cprod= 1e 7

Cdes=1

CavitationCavitation ModelsModels

Sauer Singhal

Convergence problem (OF) when RB> 1.e-4

Mass transfer calcultated by UDF ≠ mass transfer

calculated by the same integrated model

ZwartKunz

rnuc= 5.e-4

Fvap =50Fcond =0.01RB= 1.e-6

Convergence problem (OF) when RB> 1.e-4

Mass transfer calcultated by UDF ≠ mass transfer

calculated by the same integrated model

CavitationCavitation ModelsModels

Sauer Singhal

*

Mass transfer calcultated by UDF ≈ mass

transfer calculated by the same integratedmodel

ZwartKunz

rnuc= 5.e-4

Fvap =50Fcond =0.01RB= 1.e-6

Mass transfer calcultated by UDF ≈ mass

transfer calculated by the same integratedmodel

Test Cases: Naca0015Test Cases: Naca0015Test Cases: Naca0015Test Cases: Naca0015

Experimental Kunz model Sauer model

Test Cases: Naca0015Test Cases: Naca0015

Experimental Kunz model Sauer model

Test Cases: Naca0015Test Cases: Naca0015

IntroductionIntroduction

Sauer

Zwart

Test Cases: Naca0015Test Cases: Naca0015

Kunz

Test Cases: Naca0015Test Cases: Naca0015

Test Cases:Test Cases: HemisphericalHemispherical Body (Body (RouseRouse andand McNownMcNown))

P_out (pa) 13128.5

0.2

Re=13600

Test Cases:Test Cases: HemisphericalHemispherical Body (Body (RouseRouse andand McNownMcNown))

18113.5 28083.5

0.3 0.5

Re=13600

Test Cases:Test Cases: HemisphericalHemispherical Body (Body (RouseRouse andand McNownMcNown))

Coarse Grid10675 cell

Fine Grid69406 cell

Test Cases:Test Cases: HemisphericalHemispherical Body (Body (RouseRouse andand McNownMcNown))

Medium Grid47487 cell

Fine Grid69406 cell

Test Cases:Test Cases: HemisphericalHemispherical Body (Body (RouseRouse andand McNownMcNown))

Effect of Grid σ=0.2Surface pressure of measured and predicted

distribution at σ=0.2

Test Cases:Test Cases: HemisphericalHemispherical Body (Body (RouseRouse andand McNownMcNown))

Effect of Grid σ=0.2Surface pressure of measured and predicted

distribution at σ=0.2

Test Cases:Test Cases: HemisphericalHemispherical Body (Body (RouseRouse andand McNownMcNown))

Surface pressure of measured and predicted distribution at σ=0.2 .Comparison between 2 comercials code and OF (zwart modified and

original )

Test Cases:Test Cases: HemisphericalHemispherical Body (Body (RouseRouse andand McNownMcNown))

Surface pressure of measured and predicted distribution at σ=0.2 .Comparison between 2 comercials code and OF (zwart modified and

original )

Test Cases:Test Cases: HemisphericalHemispherical Body (Body (RouseRouse andand McNownMcNown))Test Cases:Test Cases: HemisphericalHemispherical Body (Body (RouseRouse andand McNownMcNown))

Test Cases:Test Cases: HemisphericalHemispherical Body (Body (RouseRouse andand McNownMcNown))

Surface pressure of measured and predicted distribution at σ=0.2 .Comparison between k-ε and k-ω sst model using modified zwart model

(left Coarse grid, left medium grid )

K-ω SST is more appropriate than k-ε

Test Cases:Test Cases: HemisphericalHemispherical Body (Body (RouseRouse andand McNownMcNown))

Surface pressure of measured and predicted distribution at σ=0.2 .Comparison between k-ε and k-ω sst model using modified zwart model

(left Coarse grid, left medium grid )

K-ω SST is more appropriate than k-ε

Test Cases:Test Cases: HemisphericalHemispherical Body (Body (RouseRouse andand McNownMcNown))

σ=0.2

Surface pressure of measured and predicted distribution.

Test Cases:Test Cases: HemisphericalHemispherical Body (Body (RouseRouse andand McNownMcNown))

σ=0.5

Surface pressure of measured and predicted distribution.

The modified Zwart model and Kunzmodel are in a good agreement with theexperimental data

The k-ω SST is more appropriate than k-εmodel.

Test Cases:Test Cases: HemisphericalHemispherical Body (Body (RouseRouse andand McNownMcNown))

The modified Zwart model and Kunzmodel are in a good agreement with theexperimental data

The k-ω SST is more appropriate than k-εmodel.

Test Cases:Test Cases: HemisphericalHemispherical Body (Body (RouseRouse andand McNownMcNown))

Test Cases:Test Cases: HemisphericalHemispherical Body (Body (RouseRouse andand McNownMcNown))

Surface pressure of measured and predicted surface pressure distribution atσ=0.2 . Modified zwart model using the two phase Euler Model

The E-E model need more calibration using the differentinterphase change forces [Bannari et al., 2008; 2009].

The vof mixture model is in a good agreement than theE-E two phase model.

Test Cases:Test Cases: HemisphericalHemispherical Body (Body (RouseRouse andand McNownMcNown))

Surface pressure of measured and predicted surface pressure distribution atσ=0.2 . Modified zwart model using the two phase Euler Model

The E-E model need more calibration using the differentinterphase change forces [Bannari et al., 2008; 2009].

The vof mixture model is in a good agreement than theE-E two phase model.

Test Cases:Test Cases: HemisphericalHemispherical Body (Body (RouseRouse andand McNownMcNown))

The amelioration of the models (in progress)

[Bannari et al., 2008; 2009- Selma et al., 2010].

Test Cases:Test Cases: HemisphericalHemispherical Body (Body (RouseRouse andand McNownMcNown))

The amelioration of the models (in progress)

[Bannari et al., 2008; 2009- Selma et al., 2010].

Used model

(Luo & Svendsen 1996)

échelle deKolmogorov

avec énergie E

breakup

d1

d2

coalescence

Used model

(Luo & Svendsen 1996)

énergie de surface

grande (uniforme)

breakup

h0 hC

d12

énergie de

surface petite

(non-uniforme)

coalescence

d12

Test Cases:Test Cases: HemisphericalHemispherical Body (Body (RouseRouse andand McNownMcNown))

[Bannari et al., 2008; 2009- Selma et al., 2010].

Test Cases:Test Cases: HemisphericalHemispherical Body (Body (RouseRouse andand McNownMcNown))

[Bannari et al., 2008; 2009- Selma et al., 2010].

Sauter mean diameter

[1] Brahim Selma, Rachid Bannari and Pierre. Proulx. "Simulation of bubbly flows: Comparison between the Direct Quadrature Method ofMoments and The Method of Classes", Chemical Engineering Science, accepted manuscript (2009), CES-D-09-00340.

Sauter mean diameter

[1] Brahim Selma, Rachid Bannari and Pierre. Proulx. "Simulation of bubbly flows: Comparison between the Direct Quadrature Method ofMoments and The Method of Classes", Chemical Engineering Science, accepted manuscript (2009), CES-D-09-00340.

[1] Brahim Selma, Rachid Bannari and Pierre. Proulx. "Simulation of bubbly flows: Comparison between the Direct Quadrature Method ofMoments and The Method of Classes", Chemical Engineering Science, accepted manuscript (2009), CES-D-09-00340.

Diamètre deSauter [m]

CM 25 DQMOM[1] Brahim Selma, Rachid Bannari and Pierre. Proulx. "Simulation of bubbly flows: Comparison between the Direct Quadrature Method ofMoments and The Method of Classes", Chemical Engineering Science, accepted manuscript (2009), CES-D-09-00340.

- Nurick (1976)

CFD

Comparaison of cavitation model predisctions with Nurick’s correlation

Test Cases:Test Cases: CircularCircular orificeorifice

Comparaison of cavitation model predisctions with Nurick’s correlation

Test Cases:Test Cases: CircularCircular orificeorifice

Conclusion and future work

The E-E model needs more calibration using thedifferent interphase change forces [Bannari et al.,2008; 2009].

Use of other test cases.

Ameliorations of existent models.

Use of the cavitation model on hydraulic turbine,and the effect on the efficiency.

Other model of turbulence and other wall function

Conclusion and future work

The E-E model needs more calibration using thedifferent interphase change forces [Bannari et al.,2008; 2009].

Use of other test cases.

Ameliorations of existent models.

Use of the cavitation model on hydraulic turbine,and the effect on the efficiency.

Other model of turbulence and other wall function

Thanks

The author wish to acknowledge the financial support ofthe FQRNT and IREQ.

The authors also wish to thank the developers of the OpenFOAMpackage for their hard work and gracious collaboration.

The author wish to acknowledge the financial support ofthe FQRNT and IREQ.

The authors also wish to thank the developers of the OpenFOAMpackage for their hard work and gracious collaboration.