Experimental study on the frictional pressure drop of biphasic fluids on the shell side of LNG spiral-wound heat exchangers under sloshing conditions

•A reliable large-scale sloshing experimental setup is built.•Periods of transient frictional pressure drop variation and sloshing are consistent under roll and pitch situations.•The time-averaged frictional pressure drop exhibits superior sloshing resistance under higher overall mass flow. A key factor affecting the performance of offshore floating spiral-wound heat exchangers is the frictional pressure drop of biphasic fluids on the shell side. A large-scale sloshing experimental setup was designed and constructed to investigate the impact of operational and sloshing parameters on the properties of frictional pressure drop. The device employed air and water as working fluids. The experimental conditions included the sloshing angle of roll and pitch ranging from 5° to 15°, heave amplitude of 1.50 × 10−1 m, sloshing period ranging from 20 s to 40 s, overall mass flow ranging from 735 kg·h−1 to 1565 kg·h−1, vapor quality ranging from 0 to 0.2, and Reynolds number of biphasic fluids ranging from 3160 to 12,040. Findings indicate that the transient frictional pressure drop fluctuates periodically during roll and pitch situations, with the same period as the sloshing period. The time-averaged frictional pressure drop exhibits superior sloshing resistance under higher overall mass flow. Furthermore, the frictional pressure drop is greater under pitch conditions compared to roll and heave conditions. Increases in overall mass flow, vapor quality, or sloshing angle result in corresponding increases in frictional pressure drop. As the sloshing period grows from 20 s to 40 s, the mean deviation in the time-averaged frictional pressure drop is −2.57 % and −2.56 % for the same vapor quality and overall mass flow situations. The considerable impact of overall mass flow, vapor quality, pitch motions, and sloshing angle on frictional pressure drop is observed, but the sloshing period is not.