Saturated nucleate flow boiling over a horizontal single and multi-cylinder under cross-flow condition

Abstract

Present work focuses on simulating flow boiling of saturated liquid to reveal associated interfacial dynamics over horizontal heated circular cylinder under vertical flow condition. Varying liquid velocities and heat fluxes are considered for simulation to cover the study of the buoyancy and inertia-dominated mixed regimes. Cross-flow situation around isolated and vertically arranged in-line cylinders are modelled using Volume-of-Fluid (VOF) based interface capturing technique and Tanasawa’s phase change model. In case of a single cylinder, at lower cross-flow rate, individual bubble life cycle can be identified; whereas, at higher cross-flow rate, a continuous but wavy column is formed behind the cylinder due to formation of the stagnation zone and associated interfacial instability. The wall temperature and void fractions distributions from bottom to top of the cylinder differentiate the azimuthally varying heat transfer mechanisms. The inter-cylinder interfacial interaction in case of multi-cylinder is shown with sequential bubble movement illustrations. As moving from the bottom cylinder to top, the bubble size is observed to be increasing.