真空条件下浓度对LiCl溶液沸腾特性的影响

沸腾换热是一种高效的换热方式，为研究除湿溶液再生的沸腾换热过程，搭建真空再生沸腾特性测试实验台，对水和质量分数分别为30%、32%、34%的LiCl溶液进行实验研究，得到溶液浓度对溶液沸腾热流密度及沸腾表面传热系数的影响。结果表明，浓度升高，表面张力增大，汽化核心数减少；黏度增大，气泡脱离困难，使扰动量减少，溶液的热流密度降低；随着浓度的增大，表面张力增大，气泡生成及脱离阻力增大，对LiCl溶液的扰动程度降低，使溶液的沸腾传热系数减小。温差增大使壁面过热度增大，气泡生成增多，加强对溶液的扰动，使溶液的热流密度及沸腾传热系数增大。

Effect of concentration on boiling characteristics of LiCl solution under vacuum

Boiling heat transfer is an efficient way of heat transfer. In order to research the boiling heat transfer processes in regeneration of dehumidifying solution, the test experiment bench of boiling characteristics under vacuum was set up. Experimental study was conducted on water, LiCl solutions with mass concentration of 30%, 32% and 34%. Obtaining the effects of solution concentration on boiling heat flux density and boiling surface heat transfer coefficients. The results shows, with the increases of concentration, the surface tension increase and number of nucleation sites decreased, viscosity increases, bubble escape difficulty, disturbance reduced, so the heat flux density and boiling heat transfer coefficients of solution reduced. With the increase of temperature difference, the wall superheat increases, bubble formation increases and the disturbance to solution increases, so that the heat flux density and boiling heat transfer coefficient of solution increase.