液体真空冷却过程中失水及浓度变化问题研究

Study on Water Loss and Concentration Change of Liquid in Vacuum Cooling Process

研究真空冷却过程中失水与液体质量之间的关系以及二元溶液的浓度变化问题。以上海理工大学能源与动力工程学院自行研制的真空冷却装置为试验平台,选取不同的水质量和容器形状进行试验以研究其对失水率的影响,另外选取不同浓度的蔗糖溶液研究真空冷却对二元溶液浓度的影响。为便于比较,提出相对失水率、相对高度,相对浓度的概念。试验结果表明,当容器内液位增加时,失水率随之增加,并且变化趋势越来越明显;采用较高的窄口容器可明显降低失水,相对失水率最低仅为1.08,实际失水非常接近理论失水;蔗糖溶液经真空冷却后浓度会有所升高,但变化不大。

The effect of liquid quantity and concentration change of binary solution on water loss were investigated in the process of vacuum cooling.A vacuum cooling device was used to carry out the experiments.The effect of water quantity and container shape on water loss rate was analyzed.The influence on binary solution of vacuum cooling was studied by using different concentration of sucrose solution.The concepts of Relative Water Loss Rate,Relative Height and Relative Concentration are put forward in order to facilitate the comparison.The experimental results show that the water loss rate will increase with the increment of water level.The water loss can be reduced effectively by using taller narrow mouth container,and the relative water loss rate can be reduced as low as 1.08 which means the actual water loss is very close to the theoretical water loss.The concentration of sucrose solution will increase after the experiment,but the variation is not obvious.