Theory Research On Heat And Mass Transfer Separation Absorption Process Of Lithium-Bromide Solution And Vapor

Absorber is the most important component in lithium-bromide absorption refrigerator. Its heat transfer areas are about 40 percents of all the components. Up to now, the method of falling film absorber has been adopted in all kinds of absorption refrigerating machine. The heat transfer and mass transfer occurred simultaneously during the working process. Based the theoretic of heat and mass transfer, the heat transfer and mass transfer have dissimilarities. Mass transfer is the most important process in the absorber. The aim of absorption is just to use the aqueous solution of lithium bromide to absorb the water vapor named mass transfer. Heat transfer is only a concomitance phenomenon, so the heat and mass transfer separation adopted will minish the bulk and weight of absorption refrigerating machines efficiently, and air cooling can also be realized.Based on the heat and mass transfer separation, a mathematical model for adiabatic absorption of lithium-bromide on sloping desk is presented, and the model is solved by the use of numerical method. An analytical solution of temperature and concentration distribution is obtained. The influences of the angle and the length of the sloping desk and the inlet temperature and concentration and the absorption pressure on the performance of heat and mass transfer are discussed.An experimental unit of lithium bromide aqueous solution falling-film is built and the investigation is carried out for the performance of the water vapor absorption on the sloping desk. Compared to the results of the numerical calculate, the results of the experiments are presented. The experiment result proves the theoretical analysis. By comparison, several problems are put forward which need further study.