气液叉流条件下受热液膜传热特性

在气液叉流条件下,就不同气相雷诺数和液膜雷诺数对液膜传热特性影响进行了实验研究.结果表明：对于确定的被冷却水水温,在液膜雷诺数增加的过程中,液膜厚度逐渐增加,热阻增加,削弱液膜换热,但雷诺数上升使得液膜湍动强度增强,强化了液膜换热;在这两个因素的协同作用下,存在最佳液膜流动雷诺数,使得液膜的换热热阻最小,换热系数最大.层流时,热量传递受温度的影响较大;湍流时,热量传递对液膜进口温度的反应不如层流敏感.

Heat transfer of heated liquid film under gas-liquid cross-flow condition

The influence of different gas Reynolds number and liquid Reynolds number that produce on falling film heat transfer was studied under gas-liquid cross-flow condition.The results indicated that as the increasing of liquid Reynolds number,the thickness and thermal resistance of liquid film increased in determined cooled water temperature,which weakened the heat transfer of liquid film.However,the increasing of liquid Reynolds number strengthened the turbulence of liquid film and enhanced heat transfer.Under the synergistic effect of these two factors,there was an optimal liquid Reynolds number which could minimize thermal resistance and maximize heat transfer coefficient of liquid film.Temperature plays an important role in heat transfer of laminar flow liquid film.Whereas,the heat transfer of turbulence liquid film flow is not sensitive to liquid film inlet temperature.