Experimental Investigation of Swirl Entry Effects on Heat and Mass Transfer in a Bubble Absorber of VARS

Abstract The absorber is a crucial element in vapor absorption refrigeration systems since it has lower heat and mass transfer coefficients during the absorption process. Among various absorber configurations aimed at improving absorption, bubble absorbers exhibit superior performance. This study explores a novel, passive improvement method employing a cavity-type swirl generator in the refrigerant stream to improve the bubble absorption process by imparting the swirl motion to the refrigerant bubbles. Experiments are performed on a copper bubble absorber within a vapor absorption system, employing an R134a–dimethylformamide working fluid pair. Experimental studies are carried out by changing the operating parameters to analyze the bubble absorber performance characteristics. The effect of the swirl generator is evaluated by comparing the solution-side heat transfer coefficient and volumetric mass transfer coefficient with and without the swirl generator. Results have shown that the swirl generator effectively enhances the bubble absorption process by improving the solution-side heat transfer coefficient by 23–102% and the volumetric mass transfer coefficient by 52–98%.