Numerical simulation demonstrates transient flow hysteresis in a semi-open impeller centrifugal pump, indicating higher pressure and turbulent energy during deceleration than acceleration.
Key Points
To investigate the transient flow characteristics and internal flow field hysteresis mechanisms in a double-volute, semi-open impeller centrifugal pump during rotational speed acceleration and deceleration.
Constructed a three-dimensional full-passage geometric model of a double-volute semi-open impeller centrifugal pump using Pro/E software.
Conducted transient numerical simulations of speed variations in ANSYS CFX applying the Reynolds-averaged Navier-Stokes equations and the standard k-epsilon turbulence model.
Speed acceleration raised internal pressure, expanded pressure fluctuation amplitude, and elevated impeller passage vorticity while reducing volute chamber vorticity.
Speed deceleration reduced overall pump pressure and impeller vorticity, whereas volute chamber vorticity initially increased before weakening, showing a distinct pressure rise on the outlet wall at t = 0.4 s.
Revealed a transient hysteresis effect where, at identical rotational speeds, total internal pressure and turbulent kinetic energy were systematically higher during deceleration than during acceleration.