Experimental investigation on frictional pressure drop of single-phase water in helical coils at high and supercritical pressure

The frictional pressure drop characteristics of single-phase water were experimentally studied in a vertically-oriented helically-coiled tube at high and supercritical pressure. Experiments were performed in wide ranges of Reynolds number. For the hydraulic roughness region with high Reynolds numbers at high pressure, the effect of surface roughness on frictional pressure drop is much higher than that of secondary flow. The frictional pressure drop of single-phase water in helical coils can be predicted by related equations just for straight tubes. For the pseudo-critical region with the great variation in the physical properties at supercritical pressures, the frictional pressure drop calculated by related equations for high pressure cases was obviously smaller than experimental data.