螺旋管空油换热器空气流动换热特性数值研究

Numerical Study on Air Flow and Heat Transfer of a Spiral Tube Air-Fuel Heat Exchanger

本文数值研究了应用于航空发动机的螺旋管空油换热器空气侧流动换热特性,分析比较了不同湍流模型并将所得结果与现有关联式进行了比较,探讨了常物性和变物性条件下空气流动换热特性的差异,分析了流动换热沿程变化及螺旋角的影响。结果表明:空气横掠螺旋管束时,第一排管和最后一排管的换热系数比中间管排小,而第一排管的压降最大,最后一排管的压降最小;螺旋角对换热系数影响较小,压降随螺旋角的增加趋于减小。

The paper numerically studies the air flow and heat transfer characteristics for a spiral tube air-fuel heat exchanger used in an aero-engine,analyzes and compares various turbulence models and compares the obtained results with existing correlations,discusses the difference of air flow and heat transfer under constant and variable air physical properties,and analyzes the changes of flow and heat transfer along the flow direction as well as the effect of helix angle.The results show that:when the air flows across the spiral tube bundle,the heat transfer coefficients of the first and last tube rows are smaller than those of the middle tube rows,whereas the pressure drop of the first tube row is the largest and that of the last tube row is the smallest;the helix angle has little effect on the heat transfer coefficient,and the pressure drop tends to decrease with the increase of the helix angle.