轴向通流旋转盘腔换热特性

针对航空发动机压气机盘腔中流动与换热现象,采用该实验的方法对等温轴向通流旋转盘腔进行研究。通过对比不同工况下局部努塞尔数和平均努塞尔数的变化情况分析旋转腔中各力对流动与换热的影响,并总结努塞尔数与各无变量参数的经验公式。结果表明:盘腔内流动与换热主要由哥氏力、惯性力与离心力控制。腔内流动区域可划分为低半径位置惯性力占主导地位的惯性对流区与高半径位置哥氏力占主导地位的旋转对流区。轴向通流流量增大使惯性力增大,转速增高使哥氏力增大。惯性力与哥氏力的增加都会增强换热,两个力对彼此对换热的影响有削弱作用,两个力的综合作用使不同工况中不同半径位置的换热变化情况不同。平均努塞尔数与局部努塞尔数随变量的变化情况基本一致。 

Heat transfer characteristics of a rotating cavity with axial throughflow of cooling air

Targeting the flow structure and heat transfer of the aero-engine compressor rotating cavity,an isothermal rotating cavity with axial throughflow was investigated experimentally. By comparing the changes of the local Nusselt number and average Nusselt number in different working conditions, the effects of various forces in a rotating system on the flow structure and heat transfer were analyzed, and correlations of the Nusselt number and non-dimensional parameters were obtained.The results showed that the flow structure and heat transfer were mainly affected by the inertia force, centrifugal force and Coriolis force. The rotating cavity can be divided into two zones: the inertial convection zone located in the low radius cavity where the inertia force occupies the leading position and the rotational convection zone located in the high radius cavity where the Coriolis force occupies the leading position.The inertia force rises with the mainstream rate and the Coriolis force rises with the angular speed.Heat transfer is enhanced with increase of the inertia force and coriolis force respectively.These two forces effects on heat transfer suppress each other.With the coaction of these two forces,heat transfer changes with various working conditions and radius. The changes of average Nusselt number and local Nusselt number are consistent with the variation of variables.