近临界CO_(2)冷却传热特性试验研究  

Experimental Study on Cooling Heat Transfer Characteristics of Near-critical CO_(2)

作　　者：文章权 范志伟 樊建人[1] 肖刚[1] WEN Zhangquan;FAN Zhiwei;FAN Jianren;XIAO Gang(State Key Laboratory of Clean Energy Utilization,Zhejiang University,Hangzhou,China,310027;Zhejiang Xinjin Air Conditioning Equipment Co.,Ltd.,Longquan,China,323700)

机构地区：[1]浙江大学能源高效清洁利用全国重点实验室,浙江杭州310027 [2]浙江新劲空调设备有限公司,浙江龙泉323700

出　　处：《热能动力工程》2025年第1期132-140,共9页Journal of Engineering for Thermal Energy and Power

基　　金：国家重点研发计划项目(2023YFB4102205);中央高校基本科研业务费专项资金资助(2022ZFJH04)。

摘　　要：CO_(2)热泵系统具有环保、紧凑的特点,且在低温环境下的制热性能优异,由于其放热侧通常工作在近临界区域,研究近临界CO_(2)的冷却传热特性成为CO_(2)热泵系统设计的关键技术问题。针对这项技术,在管径为2 mm的水平圆管中进行近临界CO_(2)的冷却传热实验,实验流量为200~400 kg/(m^(2)·s)。结果表明:相同压力下CO_(2)传热系数在准临界温度附近变化最为剧烈,随着压力远离临界压力,CO_(2)传热系数在准临界温度附近的变化趋势变缓;在平均温度远离准临界温度的区域,当流量相同时,CO_(2)传热系数的变化趋势变为平缓,并且不同压力下CO_(2)在同温度处的传热系数趋于一致;拟合了CO_(2)在平均温度28~55℃,换热压力7.5~9.5 MPa范围内的传热关联式;在准临界温度以下区域,关联式预测值与91.3%的实验值的偏差在±15%以内,在准临界温度以上区域,关联式预测值与93.9%的实验值的偏差在±15%以内。The CO_(2)heat pump system has the characteristics of environmental protection,compactness,and excellent heating performance in low temperature environment.The exothermic side of CO_(2)heat pump system usually works near the critical region,so studying the cooling heat transfer characteristics of near-critical CO_(2)is a key technical problem in the design of CO_(2)heat pump system.Aimming at this technology,the cooling heat transfer experiment of near-critical CO_(2)was carried out in a horizontal circu-lar tube with a diameter of 2 mm,and the experimental flow range was 200-400 kg/(m^(2)·s).The re-sults show that the CO_(2)heat transfer coefficient changes most violently near the quasi-critical temperature under the same pressure,and the change trend of the CO_(2)heat transfer coefficient near the quasi-critical temperature slows down as the pressure moves away from the critical pressure.In the region where the av-erage temperature is far from the quasi-critical temperature,the change trend of the CO_(2)heat transfer co-efficient becomes flat when the flow rate is constant,and the CO_(2)heat transfer coefficient under different pressures is close to the same at the same temperature.In addition,the heat transfer correlation formula of CO_(2)in the range of average temperature 28-55℃and heat exchange pressure 7.5-9.5 MPa is fitted in this paper.In the region below the quasi-critical temperature,the deviation between the predicted val-ue of correlation formula and the experimental value of 91.3%is within±15%.In the region above the quasi-critical temperature,the deviation between the predicted value of correlation formula and the exper-imental value of 93.9%is within±15%.

关 键 词：CO_(2)热泵 近临界 冷却传热特性 关联式 

分 类 号：TK124[动力工程及工程热物理—工程热物理]