Z形狭缝内两种工质沸腾汽液两相特性分析  

Study on Gas-liquid Two-phase Flow Characteristics of Two Kinds of Media in Z-shaped Channels

作　　者：郭雷[1] 张树生[1] 程林[1] 

机构地区：[1]山东大学热科学与工程研究中心,山东省济南市2500611

出　　处：《中国电机工程学报》2011年第14期71-76,共6页Proceedings of the CSEE

基　　金：国家重点基础研究发展计划项目(973项目)(2007CB206900)~~

摘　　要：为深入探索狭缝通道内沸腾换热机制,对2种不同液体在Z形狭缝通道内的沸腾汽液两相流动展开研究。利用数值模拟和自编程的方法分析汽泡生成、长大和脱离的过程,通过几何重构和界面追踪获取相界面移动和变化对系统内压降以及平均表面换热系数的影响,计算中考虑了重力、表面张力和黏性的作用。发现液体黏性的不同对汽泡生长方式和汽泡形态产生很大影响,黏性较小的液体产生汽泡的脱离直径较小,汽泡脱离频率高;表面张力和液体黏性对流动沸腾系统压降都具有较大影响;液体比热和沸点的不同导致换热系数有较大差别;结果与实验数据吻合良好,均表明水沸腾换热系数高于乙醇,Z形通道强化换热效果明显。To explore the boiling heat transfer mechanism in narrow channels, gas-liquid two-phase flow in z-shaped narrow channels was studied with two different types of media. The bubble generation, growth and departure processes were analyzed using numerical simulation and self-programming. The influence of interface movements and changes on internal pressure difference and average surface heat transfer coetficient was investigated by using geometry reconstruction and interface tracking, taking into account gravity, surface tension and viscosity during calculation. The results show that the viscosity has great influence on generation modes and shapes of bubbles, that is, the lower the viscosity is, the smaller the diameter is when the bubble departs with a higher frequency. In addition, surface tension and viscosity significantly impact the pressure drop of boiling system, and different specific heat and boiling point values result in different heat transfer coefficients. The simulation results in this paper match well with the experimental data revealed in other sources, both show that the heat transfer coefficient of water is higher than that of ethanol and z-shaped channels have better heat transfer capability.

关 键 词：换热机制 Z形狭缝 核态沸腾 汽泡动力学 

分 类 号：TK124[动力工程及工程热物理—工程热物理]