空调冷水泵变频调速特性试验研究

对流量、扬程、能耗、转速、频率等参数进行的现场测试表明,采用定压差控制的变频冷水泵的流量、能耗等参数已不能简单地按相似定律来计算,转速改变越大,测试结果与相似定律计算结果的差别也越大,尤其是流量与转速的关系与相似定律有着显著的差异,且当转速低于一定值时,管内冷水的流态会发生转变;当采用手动变频且不改变管路特性时,测试结果则与相似定律的结果相吻合,管内冷水的流态也能在很大范围内维持为充分发展的紊流.测试与分析表明,空调冷水泵变频调速特性与冷水管路系统的特性密切相关.

Experimental Research on Characteristics of Variable Frequency Chilled Water Pump in Air Conditioning System

Measurements of parameters such as chilled water flow rate(Q),pump head(H),energy consumption(N),rotation speed(n)and frequency(f)showed that,for a variable frequency chilled water pump(VFCWP)controlledunder a given differential pressure,the parameters of Q,N,etc.couldn't be calculated by the pump's affinity law.Thebigger the given differential pressure or the variation of rotation speed was,the bigger the divergence of the measuredparameters(especially the flow rate Q)and the pump's affinity law was.The flow type of chilled water in pipeline alsochanged from well-developed turbulent flow to transition region when the rotation speed n decreased to some value.While the measured results showed that,in the same system,when the frequency was changed by hand and thecharacteristics of chilled water pipe system was kept unchanged,all measured parameters were in accordance with thepump's affinity law very well,and the flow type of chilled water in pipeline was still in well-developed turbulent flowin a larger range of Q or n.It confirmed that the characteristics of VFCWP in air conditioning system closelydepended on the characteristic of chilled water pipe system.