航空发动机帽罩热气膜防冰的加热特性

Heating characteristics of aero-engine nose cone with film-heating anti-icing system

针对复合材料帽罩采用的一种热气膜防冰系统,采用计算流体力学方法研究了其内部冲击换热和外部气膜加热效果。发展了二维轴对称计算方法并与全三维计算结果进行了对比,搭建了热气吹风实验台,利用红外测温仪和热电偶测量帽罩温度,验证了数值计算方法。全面研究了不同射流雷诺数、相对冲击距和气膜缝结构参数对热气加热特性的影响,结果表明:增大射流雷诺数有利于提高内部冲击换热效果和外部气膜加热效果;最佳相对冲击距随射流雷诺数的增大而增大,射流雷诺数为10 000~40 000范围内最佳相对冲击距在5~8内取得;气膜射流能大幅提高缝后外壁面温度,加热效率与气膜缝宽和位置有关,前缘开设的气膜缝还会提升前缘冲击换热效果。

For the film heating anti-icing system used in composite aero-engine nose cone,a computational fluid dynamics method was adopted to study the internal jet impingement heat transfer and external film heating efficiency.Two-dimensional axisymmetric algorithm was developed and compared with the results calculated by three-dimensional algorithm.A hot-air blowing experimental apparatus was built up and the infrared thermometer and thermocouple were used to verify the numerical simulation method.The effects of Reynolds number,relative impingement distance and structure parameters of film slot on heat transfer characteristics were comprehensively investigated.Results show that increasing Reynolds number is conducive to improving the internal jet impingement heat transfer andexternal film heating efficiency.The optimal value of relative impingement distance increases with the increasing Reynolds number,and the optimal value is between 5 and 8 when Reynolds number is between 10 000 and 40 000.Opening film slot can significantly increase the temperature of exterior surface,and heating efficiency is related to the width and location of film slot.Opening film slot at leading edge can also enhance jet impingement heat transfer.