混合工质喷射器变工况性能研究

Study on the Performance of Zeotropic Mixture Ejector Under Variable Operating Conditions

混合工质因其温度滑移和组分变化的特性,在提高喷射制冷系统性能方面展现出巨大潜力。明晰混合工质喷射器在变工况下的运行特性,为进一步挖掘混合工质喷射制冷系统的性能改进空间提供了理论基础。本文基于真实气体模型,建立了混合工质(R32/R245fa)喷射器的数值模型,并搭建实验装置验证。研究了R32/R245fa喷射器中主流体、次流体及出口流体工况对引射性能的影响,并与纯工质(R245fa)喷射器进行对比。结果表明:R32/R245fa喷射器的引射性能显著优于R245fa喷射器;主流体压力是影响R32/R245fa喷射器性能的关键参数,当主流体压力为1003 kPa时引射比最大;R32/R245fa喷射器的引射比随次流体温度的升高线性增加;R32/R245fa喷射器在刚偏离双壅塞模式时仍能保持良好的引射比,相对于R245fa喷射器更具优势。

The use of zeotropic mixture refrigerants,which are characterized by temperature glide and compositional variation,has the potential to enhance the performance of ejector refrigeration systems.To explore the potential performance improvement of zeotropic mixture ejector refrigeration systems,it is important to clarify the operating characteristics of zeotropic mixture ejectors under variable conditions.This study presents a numerical model for a zeotropic mixture(R32/R245fa)ejector based on a real gas model.An experimental setup is constructed for validation.The study analyzes the effects of primary,secondary,and outlet stream conditions on the entrainment performance of the R32/R245fa ejector and compares it with that of the conventional pure refrigerant(R245fa)ejector.The results show that the entrainment performance of the R32/R245fa ejector is superior to that of the R245fa ejector.The primary stream pressure is the key parameter affecting the performance of the R32/R245fa ejector.The entrainment ratio reaches its highest value when the primary stream pressure is 1003 kPa.The entrainment ratio of R32/R245fa ejectors increases linearly with the rise in secondary stream temperature.Additionally,R32/R245fa ejectors maintain excellent entrainment ratios even when deviating from the double-choking mode,presenting a distinct advantage over R245fa ejectors.