HC290含油混合物水平微肋管内的流动凝结压降

实验测定了HC290含油混合物水平微肋管（长2 m,最大内径11.44 mm）内流动凝结过程的压降，实验中所用润滑油是一种制冷系统中广泛应用的润滑油Suniso 3GS，润滑油浓度范围为1.95%～5.28%；所用微肋管为内表面强化管，肋数60，肋高0.25 mm，螺旋角20°，实验所取冷凝温度为40～45 ℃，质量通量范围为40～240 kg•m^-2•s^-1.结果显示实验段内冷凝压降(入口质量含汽率为1，出口质量含汽率为0.1～0.25)随工质质量通量的增加而迅速增大，润滑油浓度对冷凝压降几乎没有影响.同时在对Kaushik和Azer压降计算关系式修正的基础上得到了适用于本实验的相应经验关系式.

FORCED CONVECTION CONDENSATION PRESSURE DROP OF HC290-OIL MIXTURES IN HORIZONTAL MICRO-FIN TUBE

Forced convection condensation pressure drops were experimentally determined for a horizontal micro-fin tube (2 m length, 11.44 mm ID) with HC290-oil mixtures. The oil was Suniso 3GS, widely used in refrigerant systems. The oil concentrations ranged from 1.95% to 5.28%. The micro-fin tube is a internally enhanced tube, which has 60 fins with a height of 0.25 mm and 20° spiral angle. The condensation temperatures varied from 40 ℃ to 45 ℃ and the refrigerant mass flux varied from 40 kg•m^-2•s^-1 to 220 kg•m^-2•s^-1. The pressure drop on the test section (inlet vapor quality 1, outlet vapor quality 0.1—0.25) increased greatly as refrigerant mass flux was increased while oil concentration showed negligible effect on pressure drop. Meanwhile based on Kaushik and Azer correlation modification, a correlation suitable to the experimental data was obtained.