NAFEMS International Journal of CFD Case Studies

Volume 2, February 2000

ISSN 1462-236X

Fluent Validation for Incompressible Flow Through a 0.5 Aspect Ratio Orifice and Compressible Flow Through a Sharp-Edged Slit

Q. G. Rayer and G. D. Snowsill
Rolls-Royce Pie, PO Box 31, Derby, DE24 8BJ, UK

https://doi.org/10.59972/nv82e8uk

Keywords: CFD, Validation, Incompressible, Cross-Flow Discharge Coefficients and Simulation

Specification of Problem

Validation against air systems problems is required to enable CFO codes to be confidently used in the design of turbine cooling air systems. CFO calculations of orifice and slit discharge coefficients (C_d) have been compared with measured and theoretical values. The literature details quantitative data for these cooling system elements. The turbulence model used critically affected the accuracy of incompressible calculations for a 0.5 aspect ratio orifice. Although commonly used in engines, this aspect ratio caused difficulties in accurately simulating flow reattachment. Sharp-edged slit compressible C_d calculations agreed with theory to 4%. These results give confidence that CFO will become a valuable tool for evaluating air system losses in novel configurations.

References

[1] ESDU (Engineering Sciences Data Unit) Item Number 81039, Vol. 3a, Flow of liquids. Pressure losses across orifice plates, perforated plates and thick orifice plates in ducts, Approved for issue 1981 with amendments A and B, March 1985. Engineering Sciences Data Unit, 251-259 Regent Street, London, WlR 7AD, UK, 1985.

[2] N. Hay, and D. Lampard, Discharge coefficient of turbine cooling holes: a review, Transactions of the ASME, 96-GT-492, 1996.

[3] User's guide for FLUENT/UNS & RAMPANT release 4.0., Fluent Incorporated, Centerra Resource Park, 10 Cavendish Court, Lebanon, NH 03766, USA, 1996.

[4] Shapiro, The dynamics & thermodynamics of compressible fluid flow, Volume 1, ISBN 0-471-06691-5, Congress Card 53-8869, 1953.

[5] Dodge, Fluid throttling devices - flow resistance 111 p1p111g and components, Product Engineering Reprint 109, McGraw-Hill, N.Y., 30 March 1964, ppl4-20, 1964.

Cite this paper

Q. G. Rayer, G.D. Snowsill, Fluent Validation for Incompressible Flow Through a 0.5 Aspect Ratio Orifice and Compressible Flow Through a Sharp-Edged Slit, NAFEMS International Journal of CFD Case Studies, Volume 2, 2000, Pages 49-67, https://doi.org/10.59972/nv82e8uk