Transient Characteristics of a High-Capacity Centrifugal Pump during Rapidly Regulating Discharge Valve

In order to reveal the instantaneous characteristics of a high-capacity centrifugal pump during rapidly regulating discharge valve,theoretical analysis and numerical simulation are employed.The transient characteristics of the pump model under off-design condition were theoretically analyzed based on the generalized basic equation of vane pumps.The study showed that a centrifugal pump with radial straight blades at off-design condition almost had no transient effect,whereas a centrifugal pump with common backward-curved blades had transient effects that were directly related to the regularity of adjusting flowrate.Calculation examples show that transient effects are insignificant.The finite volume method and re-normalization group(RNG)κ-ε turbulence model were adopted to accomplish a 3D numerical calculation of a mediumspecific-speed centrifugal pump under the off-design condition.The transient process at the off-design condition is mainly caused by the time-varying intrinsic pulsation from the stator-rotor interference and by the time-varying consequent pulsation from the changes in flow rate.

In order to reveal the instantaneous characteristics of a high-capacity centrifugal pump during rapidly regulating discharge valve, theoretical analysis and numerical simulation are employed. The transient characteristics of the pump model under off-design condition were theoretically analyzed based on the generalized basic equation of vane pumps. The study showed that a centrifugal pump with radial straight blades at off-design condition almost had no transient effect, whereas a centrifugal pump with common backward-curved blades had transient effects that were directly Mated to the regularity of adjusting flowrate. Calculation examples show that transient effects are insignificant. The finite volume method and re-normalization group （RNG） κ-ε turbulence model were adopted to accomplish a 3D numerical calculation of a medinm- spedfic-speed centrifugal pump under the off-design condition. The transient process at the off-design eondition is mainly caused by the time-varying intrinsic pulsation from the stator-rotor interference and by the time-varying consequent pulsation from the changes in flow rate.