Statistical analysis of pressure fluctuations during unsteady flow for low-specific-speed centrifugal pumps

Abstract

A three-dimensional transient numerical simulation was conducted to study the pressure fluctuations in low-specific-speed centrifugal pumps. The characteristics of the inner flow were investigated using the SST k-ω turbulence model. The distributions of pressure fluctuations in the impeller and the volute were recorded, and the pressure fluctuation intensity was analyzed comprehensively, at the design condition, using statistical methods. The results show that the pressure fluctuation intensity increases along the impeller streamline from the leading edge to the trailing edge. In the impeller passage, the intensity near the shroud is much higher than that near the hub at the inlet. However, the intensity at the middle passage is almost equal to the intensity at the outlet. The pressure fluctuation intensity is the highest at the trailing edge on the pressure side and near the tongue because of the rotor-stator interaction. The distribution of pressure fluctuation intensity is symmetrical in the axial cross sections of the volute channel. However, this intensity decreases with increasing radial distance. Hence, the pressure fluctuation intensity can be reduced by modifying the geometry of the leading edge in the impeller and the tongue in the volute.

Keywords

transient / pressure fluctuation intensity / statistics / low specific speed / centrifugal pump

References

[1] ArndtN, AcostaA J, BrennenC E, CaugheyT K. Experimental investigation of rotor-stator interaction in a centrifugal pump with several vaned diffusers [J]. ASME Journal of Turbomachinery, 1990, 112(1): 98-108

[2] GuoS, MarutaY. Experimental investigations on pressure fluctuations and vibration of the impeller in a centrifugal pump with vaned diffusers [J]. JSME International Journal, Series B, 2005, 48(1): 136-143

[3] YaoZ-f, WangF-j, QuL-x, XiaoR-fu. Experimental investigation of time-frequency characteristics of pressure fluctuations in a double-suction centrifugal pump [J]. Journal of Fluids Engineering, 2011, 133(10): 101-303

[4] KhalifaA E, Al-qutubA M, Ben-mansourR. Study of pressure fluctuations and induced vibration at blade-passing frequencies of a double volute pump [J]. Arabian Journal for Science and Engineering, 2011, 36(7): 1333-1345

[5] PavesiG, CavazziniG, ArdizzonG. Time-frequency characterization of the unsteady phenomena in a centrifugal pump [J]. International Journal of Heat and Fluid Flow, 2008, 29(5): 1527-1540

[6] SpeceR, Amaral-teixeiraJ. A CFD parametric study of geometrical variations on the pressure pulsations and performance characteristics of a centrifugal pump [J]. Computers and Fluids, 2009, 38(6): 1243-1257

[7] GonzálezJ, FernándezJ, BlancoE, SantolariaC. Numerical simulation of the dynamic effects due to impeller-volute interaction in a centrifugal pump [J]. Transactions of the ASME Journal of Fluid Engineering, 2002, 124(2): 348-355

[8] GayoJ L, GonzálezJ, Fernandez-FrancosJ. The effect of the operating point on the pressure fluctuations at the blade passage frequency in the volute of a centrifugal pump [J]. Transactions of the ASME Journal of Fluids Engineering, 2002, 124(3): 784-790

[9] SpeceR, Amaral-TeixeiraJ. Investigation into pressure pulsations in a centrifugal pump using numerical methods supported by industrial tests [J]. Computers and Fluids, 2008, 37(6): 690-704

[10] BarrioR, ParrondoJ, BlancoE. Numerical analysis of the unsteady flow in the near-tongue region in a volute-type centrifugal pump for different operating points [J]. Computers and Fluids, 2010, 39(5): 859-870

[11] FengJ, BenraF K, DohmenH J. Numerical investigation on pressure fluctuations for different configurations of vaned diffuser pumps [J]. International Journal of Rotating Machinery, 200734752

[12] YuanS-q, NiY-y, PanZ-y, YuanJ-ping. Unsteady turbulent simulation and pressure fluctuation analysis for centrifugal pumps [J]. Chinese Journal Of Mechanical Engineering, 2005, 22(1): 64-69

[13] ZhangD-s, ShiW-d, ChenB, GuanX-fan. Unsteady flow analysis and experimental investigation of axial-flow pump [J]. Journal of Hydrodynamics, Series B, 2010, 22(1): 35-43

[14] DaiC, KongF-y, DongLiang. Pressure fluctuation and its influencing factors in circulating water pump [J]. Journal of Central South University, 2013, 20(1): 149-155

[15] PeiJ, YuanS-q, BenraF K, DohmenH J. Numerical prediction of unsteady pressure field within the whole flow passage of a radial single-blade pump [J]. ASME Journal of Fluids Engineering, 2012, 134: 101-103

[16] JohannF GCentrifugal pumps [M], 2008, Berlin, Springer-Verlag Berlin and Heidelberg GmbH & Co. K: 98-105

[17] GuanX-fanModern pump theory and design [M], 2004, Beijing, China Astronautic Publishing House: 35-42