采用数值模拟与实验研究相结合的方法,以R134a为工质,研究了微通道平行流蒸发器内入口处分流板的开孔面积变化时,对蒸发器的流动和换热性能的影响.结果表明:随着分流板上的开孔孔径增大,蒸发器内的流动阻力会降低,制冷剂流量分配的均匀性变差,而制冷量却先增加后减小.分流板的开孔孔径存在一个最佳值,此时蒸发器内的阻力损失低,制冷剂的流量分配均匀性好,两者的匹配性最好,使得蒸发器的制冷量达到最大.此蒸发器中入口分流板的最佳开孔面积约为150.7 mm2.
The numerical simulation and experimental methods were used to study the efficiency of flow distribution and pressure drop of the micro-channel evaporators with parallel flow. R134a was as the working fluid. The results show that: with the same deflector struc- ture, as the open area of holes in the deflector is increased, the pressure drop of the evaporator is decreased, the flow distribution uniform- ity of refrigerant is deteriorated, and the cooling capacity of evaporator is first increased and then decreased. There is an optimum open ar- ea of holes in deflector to the micro-channel evaporator with parallel flow, where the pressure drop and flow distribution uniformity get to the best match, which leads to the maximum cooling capacity. For the type of micro-channel evaporator with parallel flow, the optimum open area of holes in the deflector is about 150.7 mm^2.