Abstract: The evaporation of single droplets containing various dissolved inorganic salts was studied experimentally. It was found that the drying process of most sample droplets in a high temperature gas stream comprised four rather than two periods, namely, (1) a constant rate period at wet-bulb temperature, (2) a falling rate period, (3) a boiling-evaporation period or constant rate period at the boiling point of the saturated solution and(4) a second falling rate period. Such a four-stage mechanism should be taken as a general one for the evaporation-drying process of droplets containing dissolved solid substances, and the disappearance of certain stages is but a special case under certain conditions. The effects of some variables such as medium temperature, initial concentration and initial diameter of droplet on the drying charateristics were investigated. The critical moisture contents corresponding to the turning points of various drying stages have been measured.

摘要： 本文研究了某些常见无机盐的不同浓度水溶液滴粒在高温气流中的蒸发干燥.发现大多数试样滴粒的干燥过程包括(1)湿球温度下的恒速干燥;(2)降速干燥;(3)沸点下恒速干燥;(4)第二次降速干燥四个阶段,而不是两个阶段.这种四阶段干燥机理可以作为对任何含溶解固体滴粒蒸发干燥过程的完整的一般化描述.研究了某些因素对干燥过程特性的影响;测定了各干燥阶段转变时的临界湿含量.