UFR 4-18 Best Practice Advice

Flow and heat transfer in a pin-fin array

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Description

Test Case Studies

Evaluation

Best Practice Advice

References

Best Practice Advice

Key Physics

Our aim in the present test-case is to predict the following physical parameters:

• The pressure drop across the matrix,
• The average and local Nusselt numbers on the bottom wall.

The temperature transport is reduced to the forced convection regime, thus predicting the dynamics of the flow is the critical issue. The two key physical phenomena which have then to be captured here are:

• The vortex shedding around the pins,
• The horseshoe vortices due to the interaction between the pins and the endwall.

Numerical Modelling

• Discretisation method
• Grids and grid resolution

Numerical scheme

• The convection scheme must be centered for the velocity components even with some upwinding for URANS computations and purely centered in LES. This is mandatory to have the unsteadiness,
• The convection scheme for the turbulent quantities can rely on an upwind scheme.

Grid refinement

• LES grid must respect around the pins and the endwalls the requirements for a wall resolved LES almost everywhere in the matrix region (Δx+<40,
• A convergence strudy must be carried out for URANS computations and this will lead to very fine meshes which might be unusual for URANS computations.

Physical Modelling

• Turbulence modelling
• Transition modelling
• Near-wall modelling
• Other modelling

Application Uncertainties

Summarise any aspects of the UFR model set-up which are subject to uncertainty and to which the assessment parameters are particularly sensitive (e.g location and nature of transition to turbulence; specification of turbulence quantities at inlet; flow leakage through gaps etc.)

Recommendations for Future Work

Propose further studies which will improve the quality or scope of the BPA and perhaps bring it up to date. For example, perhaps further calculations of the test-case should be performed employing more recent, highly promising models of turbulence (e.g Spalart and Allmaras, Durbin's v2f, etc.). Or perhaps new experiments should be undertaken for which the values of key parameters (e.g. pressure gradient or streamline curvature) are much closer to those encountered in real application challenges.

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Contributed by: Sofiane Benhamadouche — EDF

Front Page

Description

Test Case Studies

Evaluation

Best Practice Advice

References

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