Experimental investigation on frictional multiplier of steam-water two-phase flow in internally ribbed enhanced tubes

Abstract

The frictional multiplier of steam-water two-phase flow in four-head internally ribbed tubes was experimentally investigated under two test conditions - adiabatic and heated. The internally ribbed tube has the following dimensions: outside diameter 28.6 mm, wall thickness 5.8 mm, and hydraulic diameter 15.24 mm. The test tube, 2000 mm in length, was vertically installed and uniformly heated electrically. A wide range of experimental parameters were considered. The pressure range was 9-31 MPa, mass flux range was 600-1800 kg/(m2 s), and steam quality range was 0-1 in subcritical pressure region. In this study, the effects of pressure, mass flux, and steam quality on the frictional multiplier were analyzed. The corresponding empirical correlations were presented. The variation in pressure drop between the adiabatic tube and heated tube was determined. The experimental results demonstrated that the characteristics of the frictional pressure drop in the internally ribbed tube under heated and adiabatic conditions are dissimilar. The two-phase frictional multiplier in the heated tube is higher than that in the adiabatic tube. With the decrease in the pressure or increase in the steam quality, the two-phase frictional multiplier increases gradually. However, the single-phase frictional factor in the heated tube is smaller than that in the adiabatic tube in the subcritical and supercritical pressure region.