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本文研究了CO_2/丙烷混合工质的流动沸腾换热特性,实验段为内径2mm的水平光管。实验条件为:混合物中丙烷质量分数0%～100%,初始蒸发温度0～10℃,热流密度5～15 kW/m~2,质量流速200～400 kg/(m~2s)。结果表明:CO_2/丙烷混合工质的换热系数,介于两种纯净物即CO_2和丙烷之间,并随着混合物中丙烷含量的增加而减小;初始蒸发温度、热流密度或质量流速的增加均能引起换热系数的增加;对应蒸干现象的临界干度随混合工质中丙烷含量增加而增大,且蒸干会被较低的初始蒸发温度、较低的热流密度和较高的质量流速所抑制。
In this paper, the flow boiling heat transfer characteristics of CO_2 / propane mixed media were studied. The experimental section was a horizontal light tube with an inner diameter of 2mm. The experimental conditions were as follows: propane concentration 0% ~ 100%, initial evaporation temperature 0 ~ 10 ℃, heat flux 5 ~ 15 kW / m ~ 2 and mass flow rate 200 ~ 400 kg / (m ~ 2s). The results show that the heat transfer coefficient of CO_2 / propane mixture is between that of pure CO_2 and propane, and decreases as the content of propane in the mixture increases. The initial evaporation temperature, heat flux or mass flow rate The critical dryness corresponding to the phenomenon of evaporation and drying increases with the increase of propane content in the mixed working medium, and the evaporation and drying will be affected by the lower initial evaporation temperature, the lower heat flux and the higher The mass flow rate of inhibition.