对制冷剂R290在微细圆管内流动沸腾摩擦压降梯度进行了定性的理论分析和定量的实验研究，分析不同影响因素下其变化规律。实验工况：质量流率50~1 020 kg/(m2•s)、热流密度1~70 kW/m2、管径1~3 mm、饱和温度-10~25 ℃、干度0~1。实验结果表明：质量流率的增大和换热管径的减小，都会造成摩擦压降梯度和增长幅度大幅增加；热流密度值的变化不影响摩擦压降梯度，但会影响摩擦压降达到最大值的时间；摩擦压降梯度随着饱和温度和管径的减小而增大；摩擦压降梯度在中低干度时快速增加，在高干度时增速减小趋于平稳，直至达到最大值后缓慢减小。

The qualitative theoretical analysis and quantitative experimental research on flow boiling frictional pressure drop gradient of refrigerant R290 in a microtubule were carried out,and the variation law under different influencing factors was analyzed.The experimental conditions include mass flow rate of 50 to 1 020 kg/(m2•s),heat flux density of 1 to 70 kW/m2,pipe diameter of 1 to 3 mm,saturation temperature of -10 to 25 ℃,and dryness of 0 to 1.The research results show that the increase of mass flow rate and the decrease of heat transfer pipe diameter will result in the frictional pressure drop gradient and a significant increase of its growth rate; The change of heat flux density has no influence on the frictional pressure drop gradient,but impacts the time when the frictional pressure drop gradient reaches the maximum value; The frictional pressure drop gradient increases with the decrease of saturation temperature and pipe diameter; It is also found that the frictional pressure drop gradient increases rapidly at medium and low dryness,and the growth rate decreases and tends to be stable at high dryness,and then decreases slowly after reaching the maximum value.

TK172

江苏省高等学校自然科学研究面上项目(20KJB470019)；南通市科技项目(JC2021061)