对内径范围为15 mm到65 mm的垂直下降管内的空气-水两相流的摩擦压降进行了实验研究.实验在常温下进行,实验压力为0.168～0.278 MPa,液相与气相的折算速度分别为0.127～2.349 m.s-1和0.013～15.401 m·s-1,得到了1112个不同工况条件下的垂直下降管内两相流摩擦压降的实验数据点,并以本次实验数据为基础对现有文献中的两相流摩擦压降计算关联式进行了评价.研究发现:现有两相流摩擦压降关联式对本实验条件下的垂直下降管内两相流摩擦压降的计算精度随管径的增加而降低,且在弹状流与搅拌流条件下的计算值远小于实验值.“,”An experimental study on frictional pressure drop for air-water two-phase flows in vertical downward tubes is conducted in this paper.The range of tube inner diameter is from 15 mm to 65 mm.Experiments are performed at room temperature and the range of pressure is from 0.168 MPa to 0.278 MPa.The superficial velocity ranges of water and air are 0.127～2.349 m/s and 0.013～15.401 m/s,respectively.Totally 1112 experimental data are obtained,and are then used to evaluate correlations existed in present literature.The results show that the prediction accuracy of the present correlations for frictional pressure drop of air-water two-phase flows in vertical downward tubes reduces with the increase of tube diameters,and the prediction results of the present correlations are far less than the experiment values under conditions of slug flow and churn flow.