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研究了超临界压力下碳氢燃料航空煤油RP-3在竖直细圆管内混合对流,分析了浮升力及热物性对碳氢燃料在垂直管中对流换热的影响。实验中控制热流密度从200~500 k W/m2变化,进口压力变化范围为3~5 MPa,进口雷诺数从5000~10500范围内变化。研究表明:在向上流动情况中进口段存在较为明显的入口效应,换热出现恶化现象,而在向下流动中未出现;对于向上和向下流动,由于热物性的综合影响,换热系数沿流动方向增大;在较低进口雷诺数(Re=5 700)时,对于向下流动,随着浮升力影响的增大,浮升力改变了流体径向速度分布,出现了换热强化;在较高进口雷诺数(Re=10 500)时,浮升力对换热的影响依然显著;判别式Bo*数小于5.6×10-7未能预测浮升力对碳氢燃料换热影响。
The mixed convection of hydrocarbon kerosene jet kerosene RP-3 under vertical pressure in a vertical tube was studied. The effect of floatation force and thermophysical properties on the convective heat transfer of hydrocarbon fuel in a vertical tube was analyzed. The experimental heat flux density changes from 200 ~ 500 k W / m2, the inlet pressure varies from 3 to 5 MPa and the inlet Reynolds number changes from 5000 to 10500. The results show that there is a more obvious inlet effect in the inlet section in the upward flow condition, the phenomenon of exothermic heat is deteriorated but not in the downward flow. For the upward and downward flow, due to the combined effect of thermal properties, The flow direction increases; at lower inlet Reynolds number (Re = 5 700), the uplift force changes the radial velocity distribution of the fluid with the increase of the buoyancy force, When the Reynolds number is higher (Re = 10 500), the effect of buoyancy on heat transfer is still significant. The Bo * number less than 5.6 × 10-7 can not predict the effect of buoyancy on the heat transfer of hydrocarbon fuels.