摘要
本文对锯齿形低肋管强化冷凝换热机理进行了分析,提出了锯齿形低肋管强化冷凝换热的“周向效应”,导出了包括“周向效应”和锯齿外缘周长影响的表面张力作用公式和包括锯齿影响的存积角公式,提出了肋形准则。通过对四种锯齿管以R11为工质的实验得出了锯齿形低肋管汽侧冷凝换热的准则方程式,其计算值同实验值相差在±10％以内。
In this paper, the mechanism of enhancement of condensation heat transfer on saw-tooth-finned tube (STF tube) is analysed, the differential equations for heat transfer in the condensate film estab- lished tentatively and the 'peripherywise effect' proposed for explaining the mechanism of enhance- ment of condensation on STF tube. The expression for the effect of influence of the circumference of the Saw-Toothed fin periphery and, the expression for average condensate retension angle are respec- tively derived. The fin shape criterion is also proposed. Through experiments, with Rll as the working fluid, on four kinds of STF tube, the condensation heat transfer criterion equation for vapour side of the STF tube is obtained. The differences between the calculated values and the corresponding measured values are within 10 percent of the theoretical values.
关键词
低肋管
锯齿形
热管
冷凝
换热
saw-tooth-finned tube
heat transfer
enhancement of condensation
peripherywise effect
surface tension
