热泵型空调器四通换向阀容量的测定及换算

Measurement and Conversion of Four-Way Reversing Valve Capacity in Heat Pump System

四通换向阀是热泵空调中切换制冷、供热两种方式的关键部件 ,其容量值是主机厂选用的重要依据 .目前工业上对四通换向阀容量均以空气为介质进行测试 ,得出的结果比实际制冷剂循环中的容量值大得多 .为校正上述两种容量测试的差别 ,通过分析空气测试换算方法的原理 ,得出了产生上述差别的原因是制冷剂气体在四通换向阀内时通常接近饱和状态 ,其可压缩性及粘度等实际性质都会对流动过程产生影响 ,不能像空气一样视为理想气体 .参照流量测试仪表中所使用的流速膨胀系数引入介质修正因子 ,给出了从空气测量数据到实际公称容量值的换算关系 。

As an important component of a heat pump, four way reversing valve is chosen mainly according to its capacity. Now in industry, the capacity is determined by experiments with air as the working fluid. This method is simple but the result is fairly larger than the real value. In order to revise that difference, this paper analyzed the testing theory in detail and found that the capacity difference is caused by the fact that refrigerant in four way reversing valve is generally near the saturation point, and its physical characteristics will affect the flow. With the injection of medium coefficient, the conversion formula from the air test value to the real capacity was given in this paper.