Effects of Ice Formation on the Flowfield of an Aircraft Engine Inlet

The effects of typical rime and glaze ice on the performance of the M2129 S-duct inlet are computationally investigated using the steady-state RANS solution. The glaze ice accretion produces a substantial degradation of the inlet performance due to its obstructive shape to the in-flow, while the effect of the rime ice is not significant. Compared to the clean inlet, the secondary flow region at the engine face of the duct inlet is increased by 600 percent for the glaze iced inlet. Total pressure recoveries at the engine face for the rime and glaze ice case are 98.8 and 95.8 percent, respectively. Also, the glaze ice causes 26 percent reduction in the mass flow rate at the engine face. In addition, the adverse effects on the performance of the inlet are enhanced by an increase in freestream Mach numbers due to the stronger and more extensive shock formations in the inlet flow. With increasing free stream Mach numbers from M_∞ = 0.13 to 0.85, total pressure recovery decreases from 0.985 to 0.62 with the glaze ice accretion. And the level of the mass flow rate with the glaze ice accretion is 76 percent of that in ice-free condition at M_∞ = 0.13; however, it decreases to 68 percent at M_∞ = 0.475.