Shaft tubular pump is widely used in large and medium-sized pumping stations with ultra-low head. But occasionally the blade cracks or even breaks, which seriously restricts the safe and stable operation of the pump station. In order to obtain the mechanical properties of the pump rotor with different blade installation angles, the fluid-structure interaction numerical simulation method is applied to analyze the structure of the pump rotor. Based on the SST k-ω model and the structured grid of the whole flow field, the three-dimensional numerical simulation of the internal flow field of the pump device is carried out by using CFX, and the reliability of the simulation is verified by model test. Then, the static analysis and modal analysis of the pump rotor structure under different working conditions are carried out by using Workbench. From the results, it can be found that the axial force increases with the increase of blade installation angle at a same flow rate. And at a same flow rate, the maximum deformation and equivalent stress increases with the increase of the blade installation angle. Finally, the change of the blade installation angle mainly affects the third and sixth order frequency which are only showed as blade vibration. Therefore, all of these results indicate that the blade installation angle has obvious influence on the mechanical property of the rotor of shaft tubular pump.
In this study, model tests and numerical simulations are conducted to study the bi-directional full-flow pump (BFFP). Firstly, the head, efficiency and shaft power of the BFFP are significantly higher in the positive operating condition than in the negative operating condition. When the unit operates in the positive direction, the clearance reflux flow rate, the flow uniformity and velocity-weighted average angle of the impeller inlet, and the intensity of pressure pulsation are significantly greater than those during the negative operation. When the pump unit is operating at low flow rates, the clearance reflux produces a significant disturbance to the impeller inlet main flow. Two vortices appear in the near-wall area of the clearance outlet (i.e., impeller inlet), and the range of vortices is larger in the positive operation than in the negative operation. Secondly, at low-flow and design-flow conditions, the total entropy production of the pump unit in the positive direction is greater than that in the negative direction. When at small- and design-flow rates, the amplitude of pressure pulsation in the positive direction is smaller than that in the negative direction. This study will contribute to the research and development of a full-flow pump.
To study the influence of inlet guide vanes (IGVs) on the pressure pulsation of a shaft tubular pump, this paper first conducts an experiment to study IGVs. Then, numerical calculations of the shaft tubular pump with and without IGVs are performed to analyze the hydraulic performance and pressure fluctuation characteristics. Finally, the reliability and accuracy of the data are verified by a model test. Numerical simulation results show that with additional IGVs, the pressure pulsation amplitude at the impeller inlet first decreases and then increases under small-flow and design conditions but gradually increases under large-flow conditions. When the IGVs are added to the impeller inlet of the shaft tubular pump, the hydraulic loss in front of the impeller inlet increases, resulting in a significant drop in the head and efficiency of the pump device when the flow rate is less than 1.12 Qd; when the flow rate is greater than 1.12Qd, the head and efficiency of the pump device do not change significantly. IGVs can improve the condition of impeller water inflow and reduce pressure fluctuation on the blade surface.
In this study, the positive and negative power-off process of a bi-directional full-flow pump is investigated by model tests and numerical simulations, and the results show that under steady conditions, the head of the bi-directional full-flow pump in the positive direction is larger than in the negative direction. The positive power-off process of the bi-directional full-flow pump is slower than the negative power-off process. The clearance backflow rate of the bi-directional full-flow pump continues to drop during the power-off process until it remains stable under the runaway condition. The clearance backflow causes the vortex at the impeller inlet and the size of the vortex gradually decreases during the power-off process. Compared to the positive power-off process, the backflow vortex ratio is greater, and therefore, the flow pattern is poorer during the negative power-off process. The entropy production rate in the negative power-off process is significantly greater than that in the positive power-off process. The pumping condition has the largest hydraulic loss in the whole power-off process. The runaway rotational speed in the positive power-off process is higher than that in the negative power-off process, and the axial force in the positive runaway condition is 1.40 times greater than in the negative runaway condition. During the power-off process, the vibration and pressure pulsation in the negative operation is significantly greater than that in the positive operation, and the acceleration of the impeller vibration from large to small is the Y (vertical) direction, Z (axial) direction, and X (horizontal) direction. The research in this paper can provide an important reference for the design and operation of the bi-directional full-flow pump.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.