Pressure Drop Characteristics of Single-Phase Flow in Vertical Rolling Pipes

Experimental studies of single-phase pressure drop in rolling pipes were carried out.The in-side diameters of three pipes which were fixed on the rolling platform were 15mm,25mm,and 34.5mm re-spectively,the rolling periods of the rolling platform could be set as 5s,10s,15s,and rolling angles of the rolling platform were 10° and 20°.The experimental results showed that the frictional factor periodically fluctuated with the time variable,and its amplitude was obviously affected by the change of Reynolds number and pipe diameters.The amplitude and average value of frictional factor both decreased with the increase of Re number,but the bigger the tube diameter was,the larger the amplitude of frictional factor was.At any moment,the transient frictional factor increased with the increase of rolling period.However,the effect of changing rolling angles on the frictional factor was not obvious.