Investigation of pressure drop in the bubble pump of absorption-diffusion cycles

Abstract

In diffusion-absorption machines, bubble pump is one of the main components. Its role is to pump liquid from the absorber to separator by using thermal energy. The performance of the bubble pump is influenced by some parameters like heat input and its tube diameter. Bubble pump has been a candidate for extensive studies and obtained varied results, whereas it is still under debate on the improvement of the overall thermal performance when both the thermal and hydrodynamic fluctuation is considered. Meanwhile, very few studies have been devoted to investigating the two-phase flow instability in the bubble pump, and it remains inconclusive when the same outlook could be expected. In this paper, we could observe theoretically, two-phase flow instability, describing the NH3-H2O mixing in the heated bubble pump tube. In the theoretical study, we have used the two flow model to predict pressure drop in the bubble pump. The simulation results show that the pressure drops is influenced by tube diameter and heat flux.