湿式干釜直接接触传热蒸发过程

研究了非均相载热体直接加热物料的低持液量蒸馏釜即湿式干釜的传热蒸发机理。对底部进料情况下单泡滴在连续相（热载体）中的直接接触传热蒸发过程进行了数学模拟。通过模拟计算研究了泡滴的初始直径对连续相液深、泡滴完全汽化时间、瞬时传热温差以及瞬时传热系数的影响。提出了极限深度的概念，并推导出连续相极限深度的计算公式，对泡滴所处液深超过极限深度时的变化情况进行了分析。

Process of direct-contact evaporation in wet-type dry still

The mechanism of direct-contact evaporation in a “wet-type dry still” was investigated, where the hold-up of the material directly heated by the immiscible heat carrier was very low.The process of direct-contact evaporation of a single bubble in continuous phase was simulated for the case of bottom feeding.The effects of initial diameter of the bubble on the depth of continuous phase, the time of complete evaporation of the bubble, the instantaneous temperature difference of heat transfer, and the instantaneous coefficient of heat transfer were investigated by simulation.Simultaneously the definition of limited depth of continuous phase was presented, and its expression was deduced.The status of a heated bubble, which was in a deeper position than the limited depth was analyzed.