Influence of Surface Roughness on Pressure Drop in Two‐Phase Flow of Saturated Hydrocarbons

Pressure drop of propane and propylene in gas‐liquid saturation state are investigated for copper and mild steel test tubes. The surface structure of both tubes is determined with the focus variation method, yielding a six times higher roughness for the steel tube, although both tubes are manufactured in the same manner. In both tubes single phase pressure drop validation measurements are carried out and compared to known correlations. For two‐phase investigations both fluids are investigated at the reduced saturation pressure for three different mass fluxes. The vapor quality is varied.