活塞式制冷压缩机变工况下容积效率的试验研究

Experimental Study on Volumetric Efficiency of Reciprocating Refrigeration Compressor at Variable Conditions

研究了不同蒸发温度和冷凝温度下,活塞式制冷压缩机容积效率的变化。在现有理论的基础上,采用试验的方法,通过对不同工况下制冷剂质量流量的监测,定量分析了压缩机的容积效率变化规律。试验中采用某型号不同功率压缩机进行测试,其结果表明压缩机的容积效率随着蒸发温度的降低和冷凝温度的升高而降低,特别是在当蒸发温度低于-35℃时,压缩机的容积效率已经小于50%,严重影响了压缩机的能效。对于不同功率的压缩机,随着蒸发温度由-15℃下降至-40℃,其容积效率从70%多降至30%左右,功率越小的压缩机,容积效率下降得越快。特别是低蒸发温度对小功率压缩机的容积效率影响比较大,其下降率接近60%,容积效率只有30%左右。试验研究为制冷系统的性能改进提供参考,在低温制冷系统的设计时,一定要合理选用活塞式制冷压缩机,以实现节能的目标。

The effect of the evaporating temperature on the volumetric efficiency of reciprocating refrigeration compressor was studied by means of experiments. Based on the existing theory,the mass circulation rate was recorded during the experiment process,and the volumetric efficiency was calculated and analyzed quantitatively. A set of x- model compressor were used to carry out a series of experiments. The results showed that the volumetric efficiency was decreased with the decreasing evaporating temperature,especially the volumetric efficiency was lower than 50% when the evaporating temperature was lower than- 35℃,which seriously damaged the efficiency of the compressor. The decline of the evaporating temperature had a big affect on the compressor with small power. With the decrease of evaporating temperature,the volumetric efficiency was a nearly 60% decrease and the volumetric efficiency was only 30%. Therefore,during the design process of refrigeration system,a suitable selection of the compressor was important to obtain a better economy goal.