Search

A large-scale, vaned-voluted centrifugal pump can be applied as the key component in water-transfer projects. Pressure pulsation will be an important factor in affecting the operation stability. This paper researches the propagation and spatial distribution law of blade passing frequency (BPF) and its harmonics on the design condition by numerical simulation. Experimental and numerical monitoring is conducted for pressure pulsation on four discrete points in the vaneless region, which shows that the BPF is dominant. The pulsation tracking network (PTN) is applied to research propagation law and spatial distribution law. It provides a reference for frequency domain information and visualization vaned diffuser. The amplitude of BPF and its harmonics decays rapidly in the vaneless region. BPF and BPF’s harmonics influence each other. BPF has local enhancement in the vaneless region when its harmonics attenuate. In the vaned diffuser, the pulsation amplitude of BPF attenuates rapidly, but the local high-pressure pulsation amplitude can be found on the vane blade concave side because of obstruction and accumulation of the vaned diffuser. In the volute, the pulsation amplitude of BPF is low with the decelerating attenuation. This study provides an effective method for understanding the pressure pulsation law in turbomachinery and other engineering flow cases.

Ocean energy is a kind of clean and valuable renewable resource, which can be efficient utilized through turbomachinery. The turbulent pulsation effect and unsteady flow regime will cause pressure pulsation which can destroy the stability of the unit, especially at the tailing edge of blade. This paper compares pressure field change in the downstream region with different trailing edge geometry by numerical simulation and the pulsation tracking network method. The reasons for weakening downstream pressure pulsation with the Donaldson modification and the propagation law of the pressure pulsation are clarified. By Donaldson modification, the main frequency of pressure pulsation becomes the frequency of vortex shedding (f vs) and the amplitude is reduced to 10% of the original value. The propagation law of pressure pulsation has changed and the scope of influence has been expanded. The position of vortex generation can be judged by the phase variation. The weakening of the f vs amplitude is due to the stable low-pressure region and the phase difference variation. The inhibition of the convergence effect of vortex causes the weakening of the 2 f vs amplitude. This study provides an effective method and reference for understanding the downstream pressure pulsation variation of shedding vortex. • Revealing the effect on downstream pressure pulsation of different trailing edge. • Exploring the propagation law of pressure fluctuation with different trailing edge. • Proposing a judgement method of vortex generation position. • Proposing a method of spatial visualization of frequency domain information. • Summarizing the reasons for the weakening of downstream pressure pulsation. [ABSTRACT FROM AUTHOR]

A large-scale, vaned-voluted centrifugal pump can be applied as the key component in water-transfer projects. Pressure pulsation will be an important factor in affecting the operation stability. This paper researches the propagation and spatial distribution law of blade passing frequency (BPF) and its harmonics on the design condition by numerical simulation. Experimental and numerical monitoring is conducted for pressure pulsation on four discrete points in the vaneless region, which shows that the BPF is dominant. The pulsation tracking network (PTN) is applied to research propagation law and spatial distribution law. It provides a reference for frequency domain information and visualization vaned diffuser. The amplitude of BPF and its harmonics decays rapidly in the vaneless region. BPF and BPF's harmonics influence each other. BPF has local enhancement in the vaneless region when its harmonics attenuate. In the vaned diffuser, the pulsation amplitude of BPF attenuates rapidly, but the local high-pressure pulsation amplitude can be found on the vane blade concave side because of obstruction and accumulation of the vaned diffuser. In the volute, the pulsation amplitude of BPF is low with the decelerating attenuation. This study provides an effective method for understanding the pressure pulsation law in turbomachinery and other engineering flow cases. [ABSTRACT FROM AUTHOR]