低温室效应工质空调蒸发器性能模拟计算

Simulation and Calculation for the Performance of an Air-conditioning Evaporator with Low Global Warming Potential Working Fluids

建立翅片管式蒸发器的稳态分布参数数学模型,考虑蒸发器内部的实际流动状态,用Visual Basic计算机语言编写翅片管式蒸发器模拟计算程序,利用R22的计算结果与文献试验结果进行验证,得到较好的一致性。基于此模型模拟低温室效应(Global warming potential,GWP)工质R290、HFO1234yf和HFO1234ze在翅片管式蒸发器内的流动换热特性。分析改变迎面风速、制冷剂质量流量以及管外径尺寸时换热量和压降的变化情况,并与现在广泛使用的R410A进行性能的对比分析。结果表明,风速稳定时R290换热量最大,HFO1234yf最小;相同情况下,HFO1234yf与HFO1234ze最容易达到过热状态;压降相同时,R410A的质量流量最大,R290的最小;换热量相同时,HFO1234yf的质量流量最大,R290的最小。为低GWP工质翅片管式蒸发器的优化设计和系统匹配以及制冷剂的替代提供理论基础。

A distributed parameter mathematical model is set up for a finned tube evaporator under steady state,the actual flow condition is taken into consideration inside the evaporator in this model.Simulation program of the finned tube evaporator is written with VB language.Comparisons are also conducted between simulation results and data from experiment in the literature,the results show that the model has a good consistency.Based on this model,the characteristics of the flow and heat transfer of low global warming potential（GWP） working fluids R290,HFO1234yf and HFO1234ze in the finned tube evaporator are simulated.When the head-on wind speed,mass flow rate and pipe diameter size are altered,the change situation of heat exchange capacity and pressure drop are analyzed and the performance comparisons between the above low GWP refrigerants and the R410A which are now widely used are carried out.The results show that the R290 has the biggest heat exchange capacity and the HFO1234yf has the smallest under steady wind speed; HFO1234yf and HFO1234ze reach superheat state most easily in the same case.When the pressure drops are same,the mass flow rate of R410A is the maximum and the R290 is the minimum.When the heat exchange capacity is same,the mass flow rate of HFO1234yfis more than others and the R290 is smaller than the others.The model can provide theoretical basis for the optimization design and system matching of low GWP refrigerant finned tube evaporator and the refrigerant alternatives.