气泡泵压降模型评价研究

Investigation on Evaluation of Pressure Drop Models for Bubble Pump

气泡泵是单压吸收式制冷系统的关键部件之一,其内部工质的流动模拟是气泡泵设计的主要因素,然而在理论计算过程中,存在着两相流模型适用范围有限而模拟精度要求高这一矛盾,因此有必要根据气泡泵特性对现有两相流模型进行适用性评价。本文建立了气泡泵稳态压力降模型,分别对3种均相流压降模型和15种分相流压降模型组合(3种分相流摩阻压降模型分别与5种截面含气率模型组合)进行了模拟计算,并结合饱和水工质下的气泡泵实验数据,将理论值与实验值对比得出误差值进行模型评价。结果表明:Friedel摩阻压降模型结合Zuber截面含气率模型的分相流压降模型的模拟精度最高,适用性最好;均相流压降模型次之,但其计算稳定性最好。

The bubble pump is one of the key components of single pressure absorption refrigeration system,and the internal flow simulation of refrigerant is its main design factor.In theoretical calculation,the existing two phase models are not accurate enough for the simulation of the bubble pump.Therefore,it is important to make an assessment of existing pressure drop models corresponding to the bubble pump.Lots of available mathematical models of the bubble pump were evaluated in this paper,including three homogenous pressure drop models and fifteen separated phase pressure drop combination models(3separated phase frictional pressure drop models separately combining with5representative void fraction models).Comparing simulation results with experimental results based on the working fluid of saturated water,it was found that the separated phase pressure drop model with Friedel frictional pressure drop model and Zuber void fraction model is the best one.Meanwhile,the homogenous pressure drop model can work better than all others due to good reliability.