Surge Phenomenon during Slow Valve Closures in Short Pipelines

For a slow valve closure, compression waves and reflection waves interact resulting in flow reduction and creation of a transient less than Joukowsky’s pressure. This phenomenon has not been accurately defined and described. This paper provides plots of dimensionless maximum transient pressures versus dimensionless valve closure times obtained from transient, parametric simulation results for four valve inherent characteristic curves that are quick open, linear, parabolic, and equal percentage. These results match the published experimental data. The plots showed that dimensionless maximum transient pressures are less than 1 if dimensionless valve closure times are larger than 3. The dimensionless maximum transient pressures are 0.5 (or half of the Joukowsky’s pressure) when the dimensionless valve closure times are 14 for the equal percentage curve, 22 for the parabolic curve, 70 for the linear curve, and 150 for the quick opening curve. The plots provide quick references how to reduce magnitudes of transient/surge pressures by designing valve closure times for a valve type in a given pipeline system.