The effect of passive perturbation from an obstacle on heat transfer in a turbulent bubbly flow. Experimental and numerical modeling
I.A. Evdokimenko, K.A. Filippskiy, P.D. Lobanov, M.A. Pakhomov
Kutateladze Institute of Thermophysics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
Keywords: bubbly flow, channel, vortex generator, heat transfer enhancement, experiments, URANS, numerical simulation
Abstract
An experimental and numerical study was conducted to examine the effect of a passive perturbation from a vortex generator on heat transfer in a bubbly flow in a flat channel. Wall temperature measurements were taken using an infrared camera. To describe the flow dynamics and heat and mass transfer in the gas and dispersed phases, unsteady Reynolds-averaged Navier-Stokes equations were used, written taking into account the presence of polydisperse bubbles within the Eulerian approach. The influence of flow velocity, air bubble concentration, and vortex generator height on heat transfer in a two-phase gas-liquid flow was studied. It was found that the thermal pattern of separated two-phase bubbly flow behind an obstacle in the presence of a passive disturbance differs significantly from the dynamic pattern. The results demonstrated an increase in heat transfer in the bubbly flow behind the obstacle. A comparison was made between the obtained experimental and numerical data on heat transfer in a two-phase turbulent bubbly flow in the presence of an obstacle installed on the channel wall, and satisfactory agreement was demonstrated in terms of the characteristics of convective heat transfer.
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