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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。
In order to further explore the boiling heat transfer mechanism in the slit channel, the two-phase flow of boiling vapor-liquid two-phase flow in the Z-shaped slit channel was studied. The process of bubble generation, growth and detachment is analyzed by means of numerical simulation and self programming. The effects of phase interface movement and variation on the pressure drop and the average surface heat transfer coefficient in the system are obtained through geometric reconstruction and interface tracking. Gravity, surface tension and viscosity of the role. It is found that the different viscosity of liquid has a great influence on the bubble growth mode and bubble morphology. The less viscous liquid bubble has a smaller diameter of disassociation and a higher frequency of disassociation. The effect of surface tension and liquid viscosity on the flow boiling The pressure drop of the system has a greater impact; liquid specific heat and boiling point lead to larger differences in the heat transfer coefficient; The results are in good agreement with the experimental data, indicating that water boiling heat transfer coefficient higher than ethanol, Z-shaped channel to strengthen the heat transfer obvious.