摘要
从流型,压降和传热三个方面综述了以前研究者在U型管中所做的研究。指出了180°弯头对整个U型管的流型及其流型转变,压降损失及其预测方法和增强换热的影响。同时提出了今后关于U型管可能的研究方向:(1)细化曲率比等几何因素对流型压降传热的影响;(2)关注低温介质的U型管中的流动与传热;(3)以180°弯头加上距其一定距离的上下游为一个单元考虑其整体的压降损失;(4)量化气液两相流在U型管中的传热。
A review was conducted to elaborate the influence of 180 degree return bend on U-tubes from three aspects: flow pattern,pressure drop and heat transfer.The secondary flow induced in the 180 degree return bend changed the incoming flow pattern,increased the pressure loss and enhanced the heat transfer in U-tubes.It is advised that there four possible research directions of the U-tubes.(1)Refining the influence of geometric factors such as the curvature ratio on the flow pattern transition and pressure drop and heat transfer.(2)Focus on the low temperature fluid medium flowing in U-tubes.(3)Reconsider the pressure loss of U-tube taking the 180 degree return bend and its up-and downstream section as a unit.(4)Qualify the heat transfer of gas-liquid two-phase flow in U-tubes.
出处
《低温与超导》
CAS
北大核心
2013年第2期39-44,共6页
Cryogenics and Superconductivity
关键词
180°回转型弯头
流型
压降
传热
180 degree return bend
Flow pattern
Pressure drop
Heat transfer