Effect of passive perturbation from an obstacle on heat transfer in a turbulent bubble flow: experiment and numerical simulation

The influence of a passive perturbation from a vortex-generating rib on heat transfer in a bubble flow in a flat channel was studied experimentally and numerically. Wall temperature measurements were taken using an IR camera. Unsteady Reynolds-averaged Navier–Stokes equations, written with consideration of polydisperse bubbles and within the Eulerian approach, were used to describe the flow dynamics and heat and mass transfer in the gas and dispersed phases. The influence of flow velocity, air bubble concentration, and vortex-generating rib height on heat transfer in a two-phase gas-liquid flow was also studied. It was found that the thermal pattern of separated two-phase bubble flow behind an obstacle in the presence of a passive perturbation differs significantly from the dynamic pattern. The results demonstrated an increase in heat transfer in the bubble flow behind an obstacle. The paper presents a comparison between the obtained experimental and numerical data on heat transfer in a two-phase turbulent bubble flow with an obstacle mounted on the channel wall, and shows satisfactory agreement in terms of the characteristics of convective heat transfer.