进风角度对椭圆管翅式换热器传热性能影响

Investigation of air inlet angle influence on air-side heat transfer performance of finned oval tube heat exchanger

对两排椭圆管翅式换热器实验元件在不同进风角度下(30°、45°、60°和90°)的换热性能进行了实验研究,结果表明,在测试的迎风速度范围内随着进风角度的减小换热器换热性能减弱,并给出了测试工况范围内的换热性能经验关联式;对不同进风角度下空气侧换热性能进行了数值计算,与实验结果进行对比,符合良好;最后对不同进风角度下换热器内不同通道内空气平均速度的分布进行了研究,解释了换热性能差异的原因,为相应的工程应用提供理论参考。

Heat transfer performance of a finned oval tube heat exchanger with various air inlet angles (30°,45°,60° and 90°, respectively) were experimentally investigated in this study. Experimental results showed that heat transfer performance decreased with decreasing air inlet angle, and the experimental correlation of the air-side Nusselt number was obtained in the studied range of Reynolds numbers and air inlet angles. Heat transfer performance of various air inlet angles was simulated by using CFD software Ansys Fluent, and the simulated results agreed well with the experimental results. The numerical results indicated that with the decrease of air inlet angle, the uniformity of air velocity distribution in z-direction became worse, therefore, the comprehensive heat transfer performance was worse than that of the case with uniform flow distribution.