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

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 (Cd) 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 Cd 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.