This paper presents a simulation study on the vapor-bypassed evaporator for heat pump applications. The vapor-bypassed evaporator, in which a phase separator is set in the middle of the refrigerant circuit to bypass vapor refrigerant, can reduce the refrigerant pressure drop for enhancing the evaporator overall performance. A mathematical model for the vapor-bypassed evaporator is developed and the experiments were conducted to validate its accuracy. Based on the entropy generation minimization theory, the optimum phase separation positions and refrigerant channel numbers of the evaporator for various operation conditions are selected out. According to the simulation results, as the required heat transfer capacity ranges 4~10 kW, the vapor-bypassed (VB) mode obtains 25.6~84.6 $\text{kPa}$lower refrigerant pressure drop and 3.1~25.3% lower entropy generation than the conventional operation (CO) mode. Moreover, when the ambient temperature ranges 5~15°C, the entropy generation of VB mode is decrease by 22.3~11.5% than CO mode. In general, applying the vapor-bypassed technique is a promising way for improving the evaporator performance especially under high heat transfer capacity and low ambient temperature conditions.

本文介绍了一种用于热泵应用的旁路蒸发器的仿真研究。通过在制冷剂回路的中间设置相分离器以绕过蒸汽制冷剂的绕过蒸汽的蒸发器可以减小制冷剂压降，从而提高蒸发器的整体性能。建立了绕过蒸发器的数学模型，并进行了实验以验证其准确性。基于熵产生最小化理论，选择了各种工况下蒸发器的最佳相分离位置和制冷剂通道数。根据仿真结果，当所需的传热能力范围为4〜10 kW时，蒸气旁路（VB）模式获得25.6〜84.6$\text{千帕}$与常规运行（CO）模式相比，制冷剂压降更低，熵产生降低3.1〜25.3％。此外，当环境温度为5〜15°C时，VB模式的熵产生比CO模式减少22.3〜11.5％。通常，采用绕过蒸汽的技术是一种改善蒸发器性能的有前途的方法，特别是在高传热能力和低环境温度条件下。