Hydrodynamics and heat transfer in an inclined bubbly flow

Abstract

Results of experimental and numerical investigations of heat transfer and wall shear stress, in upward bubble flow in a flat inclined channel, are presented. The hydrodynamic structure is measured using the electrochemical method with miniature friction sensors. Miniature platinum thermoresistors are employed to measure the wall temperature. The set of RANS equations is used to account for the feedback effect of bubbles on mean and fluctuating flow parameters. It is shown that we can observe a significant dependence of shear stress and heat transfer on angle of channel inclination, in the bubble gas-liquid flow. The largest values of wall shear stress and heat transfer correspond to channel inclination angles of 30–50°. Intensification of wall shear stress in inclined two-phase bubble flow leads to values of 30%, and up to 15% for heat transfer. For inclination angles close to horizontal, suppression of shear stress and heat transfer of 10% and 25% respectively, was registered. Bubble size distributions along the channel length were obtained for different regimes of two-phase flow.