电动汽车CO_(2)空调涡旋压缩机变工况工作特性

Operating characteristics under variable conditions of a scrollcompressor in CO_(2) air-conditioning-system for electric vehicle

为了提升电动汽车续航里程,研究了CO_(2)空调系统变工况运行性能及涡旋压缩机工作特性。构建了耦合涡旋压缩机一维通流模型的跨临界CO_(2)空调系统的性能预测模型,并利用试验数据校核了模型有效性。对比了压缩机简单模型与通流模型变工况条件下对系统性能预测的差异,分析了涡旋压缩机吸气预压缩及排气非对称流动的变化规律。结果表明:变工况工作条件下,用恒定效率的压缩机简单模型所预测的系统工作特性指数(系统制冷量与压缩机功耗之比),比用一维通流模型,最多高20%;压缩机吸气真空度是影响吸气预压缩程度的主要因素,压缩机转速从2500 r/min增至6000 r/min,吸气预压缩程度增加1.92%,容积效率提高4.72%;排气口通流面积变化主导排气腔压力非对称分布,减小压缩机排气腔压力非对称度,有利于提高压缩机等熵效率。

In order to increase the driving range of electric vehicles,the operating performances of the air conditioning system under variable conditions and the functional characteristics of the scroll compressor were investigated.The performance prediction model of a trans-critical CO_(2) heat pump air conditioning system coupled with a one-dimensional flow model of a scroll compressor was constructed,and the validity of the model was verified by experimental data.The differences in system performance prediction under variable operating conditions between the simplified compressor model the and one-dimensional flow model were compared,and the variation characteristics of the suction pre-compression and the asymmetric flow in the discharge process were analyzed.The results show that with a constant efficiency,the system operating characteristics index(the ratio of the system cooling capacity to the compressor power consumption)predicted by the simple compressor model,is up to 20%higher than that by the one-dimensional flow model.The compressor suction vacuum degree is the main factor affecting the degree of suction pre-compression.As the compressor speed increases from 2500 r/min to 6000 r/min,the degree of suction pre-compression increases by 1.92%,and the volume efficiency increases by 4.72%.The change in the throughflow area of the discharge port dominates the asymmetric pressure distribution in the discharge chamber.The reduction of the asymmetric degree of the discharge chamber pressure is beneficial to improve the compressor isentropic efficiency.