提升管管径对有机工质气泡泵性能的影响分析

Effects of Lift-tube Diameter on Performance of Bubble Pump with Organic Working Fluids

基于气液两相漂移流理论,对以TFE（三氟乙醇）/E181（四甘醇二甲醚）溶液为工质的扩散吸收式制冷系统气泡泵建立数学模型,通过MATLAB 编程,在不同的浸没比和加热功率下,分析了提升管管径对TFE/E181气泡泵性能的影响规律.结果表明,TFE/E181 气泡泵的性能随提升管管径的变化与浸没比和加热功率密切相关;在浸没比介于0.2 - 0.7,加热功率介于200 - 1 200 W 的范围内,存在一个最佳的提升管管径使得气泡泵的溶液提升量与效率最大,且提升管最佳管径随着浸没比和加热功率的增大而增大,直至趋于弹状流最大许用直径;此外,当提升管管径一定的情况下,TFE/E181 气泡泵的溶液提升量与效率随浸没比的增大而增大,而随加热功率的变化则与提升管管径的大小有关.

As a key component in diffusion absorption refrigeration systems, the bubble pump is the motive force and has great effect on the performance and stable operation of the refrigeration unit. Based on drift-flux model, a mathematical model for the bubble pump in the diffusion absorption refrigeration system is established under MATLAB. TFE(2,2,2-trifluoroethanol)/E181(tetraethylene glycol dimethyl ether) mixture is used as working fluids. The effects of the lift-tube diameter on the TFE/E181 bubble pump performance, including solution mass flow rate and efficiency, were investigated under different submergence ratio and heating power. The results show that the TFE/E181 bubble pump performance changing with the lift-tube diameter is closely linked to the submergence ratio and heating power. When the submergence ratio ranges from 0.2 to 0.7 and heating power is between 200 W and 1200 W, there exists an optimum diameter for the lift-tube that can make the solution mass flow rate as well as efficiency of the bubble pump maximum. With the submergence ratio and heating power increased, the optimum diameter increases till it reaches slug flow's limitation. In addition, for the lift-tube with a certain diameter, the solution mass flow rate and efficiency of the TFE/E181 bubble pump increase with the increase in the submergence ratio, but their variation trends with the increased heating power depend on the size of lift-tube diameter.