论文部分内容阅读
对宽度为1和0.1 mm竖直矩形细通道内的沸腾换热展开研究,通过数值模拟的方法探索汽泡生成、长大和脱离的过程;用几何重构和界面追踪的方法获取相界面移动和变化对系统内压差以及平均表面换热系数的影响,计算中考虑了重力、表面张力和壁面黏性的作用。发现:通道宽度的不同对汽泡生长方式和汽泡形态产生很大影响,并由此导致临界热流密度的变化;表面张力在细通道沸腾换热过程中所起的作用要远远大于重力;随着通道尺寸的减小,沸腾换热系数明显增大,证明了细通道有强化换热的作用;由于数值计算中进行的理想化假设,导致数值模拟的沸腾换热系数比现有细通道沸腾换热实验数据普遍偏高。
The study of boiling heat transfer in vertical rectangular narrow channel with widths of 1 and 0.1 mm was carried out. The process of bubble generation, growth and detachment was probed by numerical simulation. The phase interface movement and Changes in the system pressure and the average surface heat transfer coefficient, the calculation of the gravity, surface tension and wall viscosity. It is found that the different channel width greatly affects the bubble growth mode and the bubble morphology, and thus leads to the change of the critical heat flux density. The effect of surface tension in the thin channel boiling heat transfer process is much greater than that of gravity. As the channel size decreases, the boiling heat transfer coefficient increases obviously, which proves that the thin channel has the effect of enhancing heat transfer. Due to the idealized assumptions in the numerical calculation, the numerical simulation of the boiling heat transfer coefficient is smaller than the existing thin channel Boiling heat transfer experimental data generally high.