Flow Pattern Simulation Of The Conventional And Tapered Bubble Pumps

With the rapid development of the global economy, the more attention is being paid to energy problem by people. Human beings are facing increasingly serious problems of global warming and energy depletion. Because of the limited global energy and resources, how to make use of energy efficiently has become a hot issue. Likewise, in the field of refrigeration and air conditioning, the energy consumption of the system has higher requirements. On the base of conventional absorption refrigeration system, the bubble pump is turned to rather than other refrigeration components as the object of study. The bubble pump has more obvious advantage of energy-saving over the mechanical pump. The bubble is generated as a result of the external heat source heating, and drives gas-liquid two-phase flow from the generator to the high position. Due to the buoyancy of the bubble, the circulation can be realized as a result of sufficient potential energy.In the paper, the simulation object is bubble pump, and the working fluid is water and lithium bromide solution. Simulation is given priority to with water, and the LiBr solution is minor. The fluent numerical simulation of traditional bubble pump is compared with the tapered bubble pump. The main tasks are as follows:(1) By dispersing calculation area, dividing mesh and defining the type of boundary and region reference to the laboratory physical model, geometrical model simulation are carried out by means of Gambit.(2) Based on boiling heat transfer theory and the vapor-liquid two-phase flow theory, the phase distribution at different moments is simulated. By observing the contours of velocity and streamline distribution, the bubble rising path and shape are briefly described.(3) Two-phase flow-type of the traditional and tapered bubble pump were simulated respectively. Flow-type was distinguished by the parameter of void fraction. The influence to flow type in different working conditions was analyzed with the parameters of lifting tube diameter, heating power, angle of lifting tube inlet and the concentration of lithium bromide solution. By simulating gas-liquid two-phase flow type and monitoring the trend of void fraction, the flow type characteristics of bubble pump device can be shown respectively.