套片式翅片管机械胀接接触热阻分析与模拟优化

本文采用有限元模拟方法,得到了套片式翅片管换热器机械胀接的翅片与基管间的胀后节点接触应力分布。提出模拟的总体接触应力并不是节点接触应力算术平均的观点和总体接触应力的计算式。通过对套片式换热器试件进行传热性能实验,获取了翅片与基管之间的接触热阻数值,由模拟计算的总体接触应力与实验接触热阻数值,计算两者的关联式。采用有限元模拟方法预测各种胀接量下的总体接触应力及最优的胀接尺寸,利用弹塑性理论计算对比模拟计算进行验证。结果发现,材料弹塑性理论计算结果与模拟计算结果的相对偏差为7. 3%,偏差较小,证明两者均具有效性。

Thermal Resistance Analysis and Numerical Optimization of Mechanical Expanded Tube-to-Fin Joints

The finite element simulation method was used to obtain the distribution of contact stress between the fin and the base pipe. It is proposed that the overall contact stress is not just the average value of the node contact stress, and a more reasonable method of calculation method is proposed. A heat transfer performance test of a sleeve-type heat exchanger was undertaken to determine the contact thermal resistance between the fin and the base pipe. The correlation between the overall contact stress and the contact thermal resistance was established. The finite element simulation method was used to determine the overall contact stress under various expansion factors, and to determine the optimal process dimension. Finally, the contact stress value calculated by the elastoplastic theory was used for internal verification. The relative deviation between the contact stress calculated using elastoplastic theory and the simulated value was small (7.3%).