Experimental and numerical investigations on pressure pulsation in a pump mode operation of a pump as turbine

Liu

et al. 2021

Preprint

High pressure pulsations excited by rotor stator interaction is always focused in pumps, especially for its control considering the stable operation. In the current research, a special staggered impeller is proposed to reduce intense pressure pulsations of a centrifugal pump with ns=69 based on alleviating rotor stator interaction. The numerical simulation method is conducted to illustrate the influence of staggered impeller on the pump performance and pressure pulsations, and three typical flow rates (0.8ФN-1.2ФN) are simulated. Results show that the staggered impeller will lead to the pump head increasing, and at the design working condition, the increment reaches about 3% compared with the original impeller. Meanwhile, the pump efficiency is little affected by the staggered impeller, which is almost identical with the original impeller. From comparison of pressure spectra at twenty monitoring points around the impeller outlet, it is validated that the staggered impeller contributes significantly to decreasing pressure pulsations at the concerned working conditions. At the blade passing frequency, the averaged reduction of twenty points reaches 89% by using the staggered impeller at 1.0ФN. The reduction reaches to 90%, 80% at 0.8ФN, 1.2ФN respectively. Caused by the rib within the staggered impeller, the internal flow field in the blade channel will be affected. Finally, it is concluded that the proposed staggered impeller surely has a significant effect on alleviating intense pressure pulsation of the model pump, which is very promising during the low noise pump design considering its feasibility for manufacturing.

Section: Introductionmentioning

confidence: 92%

Effect of the staggered impeller on reducing unsteady pressure pulsations of a centrifugal pump

Jiang

Liu

et al. 2021

Preprint

“…3 Because of its simple structure, low cost, reliable performance, and convenient maintenance, centrifugal pumps are widely used as turbines. [4][5][6][7] The current research on the internal flow of PAT includes: speed slip mechanism, 8,9 noise, 10,11 pressure pulsation [12][13][14][15][16][17][18][19][20] and energy conversion characteristics. 21 Literature 9 used different turbulence models to perform numerical calculations on PAT and found that the it has a velocity slip phenomenon, which causes the turbine head to decrease and induces vortices attached to the blade working surface.…”

Section: Introductionmentioning

confidence: 99%

Unsteady flow characteristics of energy conversion in impeller of centrifugal pump as turbine

Miao

Hong-Biao

Proceedings of the Institution of Mechanical Engineers, Part C:

et al. 2021

To study unsteady flow characteristics of energy conversion in impeller of centrifugal pump as turbine (PAT), the overall and sub-section methods are used to calculate the unsteady flow of the PAT under six working conditions. Through numerical calculations, the net input power of the impeller, the time domain change law of the fluid's work on the impeller, the time domain change law of power loss in the impeller, and the time domain change law of energy conversion in different regions of the impeller are analyzed. Results show that: the dynamic and static interference between the impeller blades and the tongue caused the fluctuation of energy conversion; with the increase of area between the head of the impeller blade and the opposite tongue, the power loss in the impeller decreases. And when the blade head completely deviates from the position of the tongue about 10°, the power loss in the impeller is minimized. The power output of the PAT at different flow rates is related to its internal flow conditions and the geometric structure of each region of the impeller. The above research results can provide guidance on how to operate the PAT impeller stably and efficiently.

“…Li et al [17] completed numerical analysis on the reduction of pressure pulsation for a double-section centrifugal pump and proposed that a combination of multi-blades, a larger radial gap, and staggering arrangements can reduce the pressure pulsation inside the pump. Zhang et al [18] explored the pressure pulsation in a nuclear reactor coolant pump. It was confirmed that pressure pulsation acting on the impeller's blade is mainly dominated by the impeller rotating frequency, the vane passing frequency, and the double blade-passing frequency, and the pressure pulsation acting on the blade's pressure surface is more intense than on the suction surface.…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigation of Unsteady Pressure Pulsation in New Type Dishwasher Pump with Special Double-Tongue Volute

Zhu

et al. 2021

Machines

Self Cite

A pressure pulsation experiment of a dishwasher pump with a passive rotation double-tongue volute was carried out and compared with the pressure pulsation of a single-tongue volute and a static double-tongue volute. The pressure pulsation of the three volute models was compared and analyzed from two aspects of different impeller speeds and different monitoring points. The frequency domain and time–frequency domain of pressure pulsation were obtained by a Fourier transform and short-time Fourier transform, respectively. The results showed that the average pressure of each monitoring point on the rotating double-tongue volute was the smallest and that on the single-tongue volute was the largest. When the impeller rotates at 3000 rpm, there were eight peaks and valleys in the pressure pulsation time domain curve of the single-tongue volute, while the double-tongue volute was twice that of the single-tongue volute. Under different impeller speeds, the changing trends of pressure pulsation time and frequency domain curves of static and rotating double-tongue volutes at monitoring point p1 are basically the same. Therefore, a volute reference scheme with passive rotation speed is proposed in this study, which can effectively improve the flow pattern and reduce pressure inside the dishwasher pump, and also provide a new idea for rotor–rotor interference to guide the innovation of dishwashers.