Study on the Influence of Hot-Air Mass Flow Rate on Combined Impingement–Film Anti-Icing of a Rotating Spinner

Abstract To efficiently utilize compressor bleed air and improve anti-icing performance, this study establishes a computational model of the combined impingement–film anti-icing for a real-configuration rotating spinner of a turbofan engine. Numerical simulations were conducted using FLUENT and FENSAP-ICE. After the numerical method was validated against experimental data, the influence of different hot-air mass flow rates on anti-icing performance under idle conditions was investigated. A counterintuitive, nonmonotonic relationship was revealed: the anti-icing performance does not improve monotonically with hot-air mass flow rate. Instead, an optimal mass flow rate of 95 g / s was identified, yielding the best anti-icing performance among the investigated cases. At lower mass flow rates, hot air failed to discharge from certain film holes on the leading edge, resulting in ice accretion around the stagnation point. At mass flow rates of 85 g / s and above, hot air discharged from all film holes, maintaining the entire surface above the freezing point. In terms of the average surface temperature, the internal heat transfer within the cavity was enhanced in the 85 g / s case, and the wall adhesion of the external hot-air film degrades, resulting in an expansion of the low-temperature region on the spinner surface compared with lower flow rates. At 95 g / s , the enhancement of the internal heat transfer became the dominant effect, raising the average anti-icing surface temperature to 15.9°C. At 105 g / s , the reduction in external heat transfer due to degraded wall adhesion slightly outweighed the enhancement in internal heat transfer, resulting in a marginal drop in the average temperature. These findings demonstrate that for combined impingement–film anti-icing, the anti-icing performance does not improve monotonically as the hot-air mass flow rate increases.