横掠1.6/1.0椭圆管换热及流阻特性的实验研究

摘要

Experiments have been performed, in which heat-mass transfer analogy andthe naphthalene sublimation technique were used, to investigate the local and overallheat transfer characteristics and flow behaviors of an elliptic cylinder of axis ratio 1.6 :1 in crossflow of air. The testing Reynolds number ranged from 7000 to 50000. The local heat transfer feature is presented and it is different from that of a circular cylinder.The local heat transfer rate is the highest on the front stagnant point, then gradually decreases with the development of the boundary layer, reaches the minimum at the separation point, then increases in the downstream part. The mean heat transfer coefficientNu and flow resistance Eu are given respectively in comparison with those of a circularcylinder. It is found that Nu is higher, but Eu is lower than that of a circular cylinder.%利用热质比拟原理及萘升华技术对空气横掠半轴比为1.6/1.0椭圆管的局部及平均换热特性以及流阻进行了实验研究.实验雷诺数范围为7000-50000.实验结果表明:该椭圆管表面上的局部换热系数分布规律与圆管相似,但分离点位置不同;其最大值在前驻点,之后,随着边界层的发展逐渐降低,在分离点达到最小值,而在尾部区域又有所回升;其平均换热系数高于圆管,而阻力低于圆管.最后,给出了平均对流换热系数和阻力实验关联式.