中文摘要：

CO2气体冷却器的结构和换热效果对CO2跨临界制冷循环的性能影响较大，为了能设计出高效的气体冷却器，有必要对CO2气体冷却器进行性能模拟和优化研究：本文首先建立了CO2气体冷却器分布参数计算模型，对CO2制冷剂的出口温度、冷却水出口温度和换热量进行了模拟计算，并与试验测试结果进行了比较，验证了模型的可靠性。然后利用该模型对CO2气体冷却器进行了优化计算，主要分析了换热管径和管长对热重比及压降的影响。结果表明，热重比随管径的增大而下降，随管长的增加而增大。综合考虑热重比和压降两方面因素，CO2气体冷却器适合选择小管径和长管长。

英文摘要：

The structure and heat transfer performance of COa gas cooler put great impact on the CO2 transcritical refrigeration cycle performance. In order to design high efficiency gas cooler, it is necessary to make performance simulation and optimization study for CO2 gas cooler. Firstly, the distributed parameter calculation model for CO2 gas cooler is developed in this paper. And the outlet temperature of CO2 , the outlet temperature of cooling water and the heating capacity are simulated. The simulation results and the experiment values are compared and the accuracy of the model is verified. Then the model is utilized to do optimization calculation for CO2 gas cooler. And the effect of tube diameter and tube length on the ratio of heating capacity to weight and pressure drop are mainly analyzed. The results show that the ratio of heating capacity to weight drops with the increase of tube diameter, and increases with the increment of tube length. As the two factors of the ratio of heating capacity to weight and pressure drop are considered comprehensively, it is suited to select small diameter tube and long tube length for CO2 gas cooler.