Numerical simulations of bubble condensation under a wall effect in a subcooled liquid flow

Abstract

This study extends our recent research [1], which applied a high-order monotonicity-preserving scheme, to numerically investigate the wall effects on single-bubble condensation by a subcooled liquid in a vertical tube. Our analysis examines the bubble lifetime, interfacial heat transfer coefficient, and flow fields to understand the influence of the tube wall. A decrease in the tube diameter leads to longer persistence of condensing bubbles, their disappearance at higher positions, and a decrease in the condensation rate. This reduction is attributed to insufficient interaction between the subcooled liquid and the bubble near the wall, resulting from backflow at narrow gaps between the bubble and the wall. Notably, in scenarios with large initial bubble diameters and small tube diameters, the presence of the wall mitigates the deformation of condensing bubbles due to a weakened recirculating flow, thus highlighting the pivotal role of the tube diameter in bubble condensation by a subcooled flow.