INVESTIGATION OF THE HYDRODYNAMIC STRUCTURE OF A DETACHED TWO-PHASE BUBBLE FLOW AND THE HEAT EXCHANGE IN A RECTANGULAR CHANNEL WITH AN OBSTACLE

An experimental investigation of the hydrodynamic structure of a detached two-phase bubble fl ow and the heat exchange in a channel with an obstacle in the form of a rectangle, an isosceles trapezoid, or a rectangular trapezoid has been performed. The experiments were carried out for the fl ow of a liquid and with a gas content β = 0–5% at Reynolds numbers falling within the range 5000–12,500. The total hydrodynamic characteristics of this fl ow were measured by the PIV/PLIF method. It is shown that the introduction of bubbles into a liquid fl ow in the indicated channel shifts the points of its reattachment upstream, as compared to that of the one-phase fl ow, which is due to the increase in the velocity gradient of the two-phase liquid fl ow in the near-wall region of the channel. For estimating the heat exchange in the channel, the temperature of the outer wall of a heated stainless-steel plate mounted fl ush with the channel wall, was measured with the use of an infrared imager. It was established that the combined eff ect of the introduction of an obstacle into the channel and of bubbles into the liquid fl owing in it makes it possible to intensify the heat exchange in the channel by 60%.
An experimental investigation of the hydrodynamic structure of a detached two-phase bubble fl ow and the heat exchange in a channel with an obstacle in the form of a rectangle, an isosceles trapezoid, or a rectangular trapezoid has been performed. The experiments were carried out for the fl ow of a liquid and with a gas content β = 0–5% at Reynolds numbers falling within the range 5000–12,500. The total hydrodynamic characteristics of this fl ow were measured by the PIV/PLIF method. It is shown that the introduction of bubbles into a liquid fl ow in the indicated channel shifts the points of its reattachment upstream, as compared to that of the one-phase fl ow, which is due to the increase in the velocity gradient of the two-phase liquid fl ow in the near-wall region of the channel. For estimating the heat exchange in the channel, the temperature of the outer wall of a heated stainless-steel plate mounted fl ush with the channel wall, was measured with the use of an infrared imager. It was established that the combined eff ect of the introduction of an obstacle into the channel and of bubbles into the liquid fl owing in it makes it possible to intensify the heat exchange in the channel by 60%.
Author:  I. A. Evdokimenko, P. D. Lobanov, A. V. Chinak, K. A. Filippskii, E.-K. Si-Ahmed, C. Gentric, W. Blel, J. Legrand
Keywords:  two-phase fl ow, bubbles, detached fl ow, heat exchange, obstacle
Page:  173