Abstract
The cross-sectional shape of the lift pipe of the bubble pump is considered to have a significant impact on the merging of rising bubbles. The effects of cross-sectional shapes of pipes and Reynolds number on the rise and coalescence of near-wall bubbles in lithium bromide solutions are investigated. A hybrid thermal multiphase model incorporating the D3Q15 pseudopotential multiphase lattice Boltzmann model with a large density ratio and the finite difference method is utilized. And the volume translated Peng-Robinson (VTPR) state equation is adopted. It is found that the merging time of rising bubbles near the walls of rectangular, circular, elliptical, and triangular cross-section pipes increases in order at the same Reynolds number. Under the same cross-sectional conditions of the pipes, a suitable increase in the Reynolds number will accelerate the merging of bubbles near the wall. This study may offer valuable insights for informing the design of pipe types for bubble pumps in absorption refrigeration systems.
