Numerická simulace vtokových vírů

Numerical simulation of pump-intake vortices

conference paper

en

Pump pre-swirl or uneven flow distribution in front of the pump can induce pump-intake vortices. These phenomena result in blockage of the impeller suction space, deterioration of efficiency, drop of head curve and earlier onset of cavitation. Real problematic case, where head curve drop was documented, is simulated using commercial CFD software. Computational simulation was carried out for three flow rates, which correspond to three operating regimes of the vertical pump. The domain consists of the pump sump, pump itself excluding the impeller and the delivery pipe. One-phase approach is applied, because the vortex cores were not filled with air during observation of the real pump operation. Numerical simulation identified two surface vortices and one bottom vortex. Their position and strength depend on the pump flow rate. Paper presents detail analysis of the flow field on the pump intake, discusses influence of the vortices on pump operation and suggests possible actions that should be taken to suppress the intake vortices.

Předrotace nebo nerovnoměrné rozdělení proudění na vstupu do čerpadla může vyvolat vunik vtokových vírů. Tento jev způsobuje ucpávání sacího prosturu čerpadla, zhoršení účinnosti, pokles měrné energie nebo vznik kavitace. Článek se zabývá CFD simulací proudění ve skutečné čerpadlové jímce, kde byl u čerpadla pozorován pokles dopravní výšky. Pro 3 různé průtoky je dokumentován vznik vtokových vírů a jejich chování v závislosti na provozním bodě. V závěru jsou pak doporučena opatření pro potlačení vtokových vírů.

Pump pre-swirl or uneven flow distribution in front of the pump can induce pump-intake vortices. These phenomena result in blockage of the impeller suction space, deterioration of efficiency, drop of head curve and earlier onset of cavitation. Real problematic case, where head curve drop was documented, is simulated using commercial CFD software. Computational simulation was carried out for three flow rates, which correspond to three operating regimes of the vertical pump. The domain consists of the pump sump, pump itself excluding the impeller and the delivery pipe. One-phase approach is applied, because the vortex cores were not filled with air during observation of the real pump operation. Numerical simulation identified two surface vortices and one bottom vortex. Their position and strength depend on the pump flow rate. Paper presents detail analysis of the flow field on the pump intake, discusses influence of the vortices on pump operation and suggests possible actions that should be taken to suppress the intake vortices.

čerpadlo, vtokový vír, vír, CFD

pump, intake vortex, swirl, CFD

18.11.2014

TU Liberec

Proceedings of the International conference Experimental Fluid Mechanics 2014

525–530

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