Numerical investigation of a centrifugal pump running in reverse mode

Abstract

This article reports a work on the three-dimensional flow simulation in a centrifugal pump operating in reverse mode. The simulations were carried out with the commercial code Fluent using unsteady flow calculations together with a sliding mesh technique. Hence, it was possible to account for the effect of blade—tongue interactions on the local flow. The numerical predictions were compared with the experimentally determined performance characteristics and also with the static pressure distribution obtained around the periphery of the impeller. Once validated, the numerical model was used to investigate the global flow. Additionally, the total radial force (steady and unsteady components) on the impeller for a number of flowrates was estimated. It was found that the unsteady radial force (peak to peak) varied between 24 and 54.3 per cent of the steady value within the considered flow interval. The maximum force amplitude was reached when the trailing edge of one blade (pressure side) was located 3° downstream of the tongue tip.

Effects of impeller diameter and rotational speed on performance of pump running in turbine mode

“…Most of the researchers have studied the performance in pump and turbine modes, either experimentally [15,32] or numerically [18,44], at same rotational speed. Usually, best efficiency point (BEP) of pump running in turbine mode is obtained at higher head and discharge compared to that in pump mode [4,14,18,45,46].…”

“…Nourbakhsh [32], Yang et al [43], Fernandez et al [44], Morros et al [47], Sheng et al [53], Sedlar et al [54], Yang et al [58] as shown in Fig. 21(b), which was found to vary in the range of ±13%.…”

Preliminary Development of a Method for Impact Erosion Prediction in Pumps Running as Turbines

“…On the other hand, one of the main limitations in the use of PATs arises from the little knowledge about their performance and their internal behavior in both steady and transient conditions, because the characteristic curves are rarely provided by manufactures. Several literature studies proposed various methods to overcome such limitation, relying on either experimental testing [8][9][10] or numerical simulations [11][12][13].…”

“…Several models were developed based on the Computational Fluid Dynamics (CFD) technique, which couples the Reynolds Averaged-Navier Stokes (RANS) equations with turbulence models. Avoiding the significant time-demand and the expensive costs related to the experimental researches, CFD models allow both the performance prediction [11][12][13] and the flow field calculation, allowing the investigation of secondary flows, internal head losses, generated force and torque and cavitation [14]. Furthermore, the optimization of the performance of the machine is also possible by simulating different geometrical configurations [15,16].…”

Small-Scale Hydropower Generation in Water Distribution Networks by Using Pumps as Turbines

“…They represent an alternative to micro-turbines, providing interesting efficiencies and significant working conditions, at the expense of lower investment and maintenance costs. In the literature, due to the limited information about the PAT performances provided by manufactures, several theoretical [1], experimental [2][3][4] and numerical [5,6] models were proposed to assess the PAT characteristic curves at different operations.…”