摘要
对CO2在细径管内蒸发换热特性进行了研究。试验管为内径4 mm长为0.5 m的光滑紫铜管。实验中参数变化范围为,蒸发温度1-15℃,质量流速100-300 kg/m2s,热流密度2-18 kW/m2,干度0.1-0.9。实验结果表明CO2 蒸发换热系数高于氟利昂类制冷剂,蒸发温度和热流密度对换热系数影响显著,而质量流速的影响相对较弱,传统制冷剂的换热系数关联式不适用于CO2;二氧化碳的压力损失随着热流密度和质量流速的增加而增加,随着蒸发温度的上升而减小,CO2压力损失小于氟利昂类制冷剂。
Evaporating heat transfer characteristics of carbon dioxide （CO2） in a horizontal thin tube were investigated experimentally. Tested was a smooth copper tube that had a 4 mm inner diameter and 0.5 m length. Experiments were conducted for 1～15℃ evaporating temperatures, 100～300 kg/m^2s mass fluxes, 2～18 kW/m^2 heat fluxes, and 0.1～0.9 vapor qualities. The experimental results showed that the evaporating heat transfer coefficients of CO2 were higher than that of Freon refrigerants, the heat transfer coefficients of CO2 were strongly affected by the evaporating temperature and heat flux, however the effect of the mass flux on such coefficient was relatively weak, and the heat transfer coefficient correlation developed for traditional refrigerant was unsuitable for the CO2. The pressure drops of CO2 increased with increasing the heat flux, but decreased with increasing the evaporating temperature, the pressure drops of CO2 was smaller than that of the Freon refrigerants.
出处
《工程热物理学报》
EI
CAS
CSCD
北大核心
2005年第5期823-825,共3页
Journal of Engineering Thermophysics
基金
北京市科委资助项目(No.H021820041420)
关键词
二氧化碳
蒸发换热
压降
细径管
carbon dioxide
evaporating heat transfer
pressure drops
thin tube
