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航空发动机后轴承腔内壁与滑油的换热分析是轴承腔热防护结构设计的基础。对航空发动机轴承腔内壁换热模拟试验件开展试验与数值模拟研究,得到了滑油油膜对轴承腔内壁的换热影响。通过测量试验件外壁面、内壁面以及滑油油膜的温度得到了试验件内壁面换热热流密度与换热系数的分布;结合CLSVOF(Coupled Level Set and Volume Of Fluid)油/气两相流以及热-流-固耦合计算方法对试验件进行了换热分析,并将内壁对滑油的局部热流量的计算结果与试验结果进行了对比,结果显示两者在各个工况下均吻合较好。通过将局部换热系数计算值与当地的滑油流动雷诺数Rel进行对比分析,结果显示内壁局部努赛尔数Nuw与Rel的0.7次方成正比关系。另外,对转速对换热的影响进行分析得到Nuw与旋转雷诺数Re_(rot)的0.345次方呈正比关系。
The heat transfer analysis of the inner wall of the aero-engine rear bearing cavity and the oil is the basis of designing the thermal protection structure of the bearing cavity. Aeroengine bearing cavity wall heat transfer simulation test carried out on the experimental and numerical simulation study, obtained the oil film on the bearing cavity wall heat transfer. The distributions of heat flux and heat transfer coefficient on the inner wall of the test piece were obtained by measuring the temperature of the outer wall, inner wall and oil film of the test piece. Combining with CLSVOF (Oil-Gas Two-Phase Flow) Heat-fluid-solid coupling calculation method was used to analyze the heat transfer of the test pieces. The calculation results of the local heat flux of the inner wall to the lubricating oil were compared with the test results. The results show that the two agree well with each working condition . By comparing the calculated local heat transfer coefficient with the local Reynolds number Rel of the oil flow, the results show that the inner wall local Nusselt number Nuw is proportional to the 0.7 power of Rel. In addition, the effect of rotational speed on heat transfer was analyzed to find that Nuw is directly proportional to the 0.345th power of revolving Reynolds number.