A Computational Investigation of Icing effects on an S-Duct Inlet

The effects of a typical glaze ice accretion shape on the performance of the M2129 S-duct inlet are computationally investigated for a range of flight Mach numbers. A Reynolds-Averaged Navier-Stokes (RANS) code with k-o> turbulence model is used to simulate the compressible viscous flow in the S-duct inlet. The glaze ice accretion on the cowl lip is modeled on a steady-state basis f rom N A S A LEWICE3D code. The results show that the total pressure recovery is reduced and the compressor face distortion level is increased with flight Mach number. A reduction of 22 .8% in total pressure recovery is calculated for a flight Mach number of 0.85 in fully-developed glazed ice condition. The massive flow separations in the inlet induced by the glaze ice horn shapes also create a mass flow reduction in the inlet between 27 and 33% as compared to clean inlet for flight Mach numbers of 0.13 and 0.475, respectively. The combined effects of reduced total pressure recovery and the reduced mass flow rate results in a reduction of engine thrust between ~30 and 6 0 % from low speed flight to Mach 0.85.