Three-Dimensional Numerical Studies on Optimizing the Discharge Coefficient of Screech Holes Resembling that of an Afterburner Using CFD Technique

Abstract

This numerical work is pertinent to exploring the effect of variation in momentum flux ratios, and geometrical parameters on discharge coefficient (Cd) of single and multiple row anti-screech hole arrangements which resembles as that of a conventional afterburner. The three-dimensional fluid flow domains of both single hole and multiple row hole configurations have been modelled in ANSYS ICEM CFD 20.0 tool and discretized with hexahedral elements to capture the velocity boundary layers more accurately. Flow physics between core and bypass flow through the anti-screech holes are obtained by solving the governing equations, namely the continuity, momentum in three directions and energy equations through the CFD code. Turbulence is captured by Reynolds averaged Navier–Stokes (RANS) two equation model, namely shear stress transport (SST) k-ω mode of closure. It is observed that Cd value increases in direct proportion to the diameter of the hole in case of single row hole configuration. An interesting fact of higher Cd values have been observed for trailing holes in case of multiple row hole configuration compared to the initial holes. The contours representing the static pressure and velocity along the midplane of the domains have been presented and analysed for exploring more insight into complex physics. The effect of hole diameter at lower and higher momentum flux values have been explored in this study with respect to the operating density, and it has been reported that Cd values for the initial holes are lesser than trailing holes in case of multiple row configuration.