Experimental studies on the performance of multiple tubes bubble pump with R134a-TEGDME

Abstract

A closed multiple lifting tube bubble pump setup with pressure difference has been built to explore the vapor generating and liquid pumping performance of diffusion gas generating bubble pump, which is used in diffusion absorption heat transformer. In all the experiments, R134a and TEGDME were employed as diffusion gas and absorbent. The influences of concentration (the mass fraction of R134a in the solution), motive head, lifting tube number and heat input on the performance of bubble pump were investigated. The R134a mass flow rate was used to evaluate vapor generating performance, while the dilute solution mass flow rate and pumping ratio were used to evaluate liquid pumping performance. The experimental results showed that: (1) the increase of concentration was beneficial to generation of R134a which resulted in larger R134a flow rate and lower generating temperature, and it also led to larger dilute solution flow rate; (2) larger motive head led to larger R134a flow rate and smaller pumping ratio, but resulted in higher pressure and generating temperature; (3) the variations of R134a flow rate, dilute solution flow rate and pumping ratio were not varied when lifting tube number changed, but the upper limit of R134a and dilute solution flow rate increased significant with the increase of lifting tube number. It was concluded that the bubble pump with multiple lifting tube had little limitation to the fluid flow rate. The results obtained in the paper will be helpful to the further study of diffusion gas generating bubble pump.