液相粘性对载气蒸发传热性能影响的研究

载气蒸发是在饱和液体中引入一种惰性气体,它成为汽比中心,使液体的汽化由加热壁面转移到气－液相界面上。载气的引入,降低了壁面液体过热度,同时也强化了传热。本文以空气－水和空气－ＣＭＣ水溶液两种物系,在 φ２５ ｍｍｘ２．５ ｍｍ,长３００ ｍｍ的短垂直管中,在气泡区进行了载气蒸发过程的传热研究,并对载气蒸发的传热机理进行了分析,提出了关联加热管内平均传热膜系数的方程式。

Study of Effect of Liquid Viscosity on Heat Transfer in Gas Carrying Evaporation

Gas Carrying Evaporation"(GCE)is a process with an inert gas introduced into the flow boiling liquid so that the gas introduced becomes the vaporization centre of the liquid, and the boiling on the heating surface being suppressed. In the experiment,the heat transfer coefficient of GCE of Newton's fluid with air as carrying gas is carried out in a vertical tube under vacuum for bubbly flow regime. The mechanism of enhancement of heat transfer of GCE is disussed and the effect of a quick diffusion of liquid vapor at the initial contact instant of gas with flow boiling liquid is also studied. At last, a correlation of experimental data based on an additive model is obtained.