混合相态冰晶积冰的数值研究

在发动机内流的高温作用下,所吸入冰晶会部分融化为液态水,冰水混合相态条件下发动机内部表面会形成积冰,冰晶积冰会导致发动机喘振、熄火,甚至会由于冰脱落而造成内部结构损伤。为了对混合相态条件下冰晶积冰问题进行深入研究,以NACA0012翼型为对象,通过数值计算分析研究了环境温度、马赫数等参数对积冰形态、收集系数以及积冰生长率的影响,并分析了融化率对积冰过程的作用机制。结果表明:混合相结冰条件下若达到最大结冰厚度,需满足有足够的冰晶和液态水含量条件;环境温度直接影响了湿球温度变化,而随环境温度升高,液膜的厚度和润湿范围也随之增大。此外降低环境温度或增大马赫数,翼型前缘驻点处结冰量和积冰速率均有明显增加。

Numerical simulation of ice crystal icing under mixed-phase conditions

Ice crystal icing is an essential menace to flight safety.The inhaled ice crystals by the engine will be partially melt into liquid water due to the high temperature of the internal flow,and the mixed phase conditions will cause ice accumulated on the internal surface of the engine,which may give rise to the engine surge,stall,and even internal structural damage due to ice shedding.Ice crystal icing under mixed phase conditions on the NACA0012 airfoil is numerically investigated.The mechanism of melting rate on ice accretion and the influences of ambient temperature and Mach number on the icing shape,collection efficiency and icing growth rate are analysed.Whether the ice accretion can reach the maximum icing thickness under the mixed phase condition,depends on to what extent the ice crystals and liquid water content can be reached.The ambient temperature directly affects the change of the wet bulb temperature,and as the ambient temperature increases,the thickness and wetting limit of the liquid film also increase.In addition,reducing the ambient temperature or increasing the Mach number dramatically increase the amount and rate of ice formation at the stagnation point of the airfoil leading edge.Current research paves the way for further research on mechanism of ice crystal icing accumulation.