基于CFD的直升机中间减速器机匣内外热平衡特性

Internal and External Heat Balance Characteristic of Helicopter Intermediate Reducer Casing based on CFD

以中间减速器为研究对象,建立了其热-流耦合计算模型,运用Fluent仿真技术,设定了机匣外流场的边界条件,对中间减速器机匣内外热平衡特性进行了分析。简化了机匣内热源施加方法,分析了不同气流速度下机匣壁面的压力、对流换热系数及温度分布的影响规律。结果表明,不同气流速度下,机匣迎风面均出现压力最大值,机匣两端面与背风面处于负压状态,与外部空气流场的进出口位置有关;机匣迎风面温度较机匣背风面的低;随着气流速度的增加,机匣散热性能增强,但壁面压力也在增高。因此,选定气流速度应从机匣散热和强度两方面综合考虑。

Taking an intermediate reducer as the research object,the thermal-fluid coupling calculation model is established,and the boundary conditions of the external flow field of the intermediate reducer is set by using Fluent simulation technology,internal and external heat balance of the intermediate reducer are analyzed.The method of applying heat source inside the casing is simplified,and the effects of different air velocities on the pressure,convective heat transfer coefficient and temperature distribution of the casing wall are analyzed.The simulation results show the maximum pressure appears on the windward side of the casing under different air velocities,and the two end faces of the casing and the leeward side are in a negative pressure state,which is related to the inlet and outlet position of the external air flow field.The temperature of the windward side of the casing is lower than that of the leeward side.With the increase of air velocity,the heat dissipation performance of the casing is enhanced,but the wall pressure is also increasing.Therefore,the air velocity should be considered from the heat dissipation and strength of the casing.