2023
Yan, Tianxu; Qiu, Baoyun; Yuan, Jianping; Pavesi, Giorgio; Zhao, Fangling; Wang, Huijie
Flow State at Impeller Inlet: Optimization of Conical Frustum Section of Elbow Inlet Conduit in Large Low-Lift Pump Station Journal Article
In: Journal of Fluids Engineering, vol. 145, iss. 4, 2023, ISSN: 0098-2202.
Abstract | Links | BibTeX | Tags: Impeller Inlet, Pump, Pump Station
@article{Yan2023,
title = {Flow State at Impeller Inlet: Optimization of Conical Frustum Section of Elbow Inlet Conduit in Large Low-Lift Pump Station},
author = {Tianxu Yan and Baoyun Qiu and Jianping Yuan and Giorgio Pavesi and Fangling Zhao and Huijie Wang},
doi = {10.1115/1.4056452},
issn = {0098-2202},
year = {2023},
date = {2023-01-01},
urldate = {2023-01-01},
journal = {Journal of Fluids Engineering},
volume = {145},
issue = {4},
publisher = {ASME International},
abstract = {In large low-lift pump stations, the pump assembly comprises an inlet conduit, a pump, and an outlet conduit. A short conical frustum section that connects the elbow section with the impeller inlet directly affects the impeller inflow state, thereby influencing the overall performance. Therefore, investigating the conical frustum section contributes to studying the effect of inflow states on the performances of pump assemblies and similar pumping systems. To improve the pump assembly efficiency, three parameters of the conical frustum section, i.e., the contraction angle, height, and centerline inclination angle, are investigated and optimized via univariate and multivariate analyses. The flow field and external characteristics of the pump assembly are investigated via computational fluid dynamics simulation with a constant head. Furthermore, a comprehensive analysis and discussion of the performance improvement mechanisms are presented. The results indicate that the axial velocity distribution at the impeller inlet conforming to the cascade high-efficiency characteristics will achieve a better pump performance compared with a uniform distribution. The pump efficiency distribution can be predicted and visualized based on the cascade efficiency characteristics and the flow state at the impeller inlet using a machine learning method. In addition, the directions and distribution of the lateral and axial components of the inflow velocities have great impacts on the circulation distribution. A sensible circulation distribution at the guide vane outlet can suppress the entropy production and reduce hydraulic loss of the outlet conduit. In this case, a significant increase in the pump assembly efficiency is obtained.},
keywords = {Impeller Inlet, Pump, Pump Station},
pubstate = {published},
tppubtype = {article}
}
In large low-lift pump stations, the pump assembly comprises an inlet conduit, a pump, and an outlet conduit. A short conical frustum section that connects the elbow section with the impeller inlet directly affects the impeller inflow state, thereby influencing the overall performance. Therefore, investigating the conical frustum section contributes to studying the effect of inflow states on the performances of pump assemblies and similar pumping systems. To improve the pump assembly efficiency, three parameters of the conical frustum section, i.e., the contraction angle, height, and centerline inclination angle, are investigated and optimized via univariate and multivariate analyses. The flow field and external characteristics of the pump assembly are investigated via computational fluid dynamics simulation with a constant head. Furthermore, a comprehensive analysis and discussion of the performance improvement mechanisms are presented. The results indicate that the axial velocity distribution at the impeller inlet conforming to the cascade high-efficiency characteristics will achieve a better pump performance compared with a uniform distribution. The pump efficiency distribution can be predicted and visualized based on the cascade efficiency characteristics and the flow state at the impeller inlet using a machine learning method. In addition, the directions and distribution of the lateral and axial components of the inflow velocities have great impacts on the circulation distribution. A sensible circulation distribution at the guide vane outlet can suppress the entropy production and reduce hydraulic loss of the outlet conduit. In this case, a significant increase in the pump assembly efficiency is obtained.
2016
Yang, Jun; Yuan, Shouqi; Pavesi, Giorgio; Li, Chun; Ye, Zhou; Shouqi, Yuan
Study of Hump Instability Phenomena in Pump Turbine at Large Partial Flow Conditions on Pump Mode Journal Article
In: Journal of Mechanical Engineering, vol. 52, iss. 24, pp. 170, 2016, ISSN: 0577-6686.
Abstract | Links | BibTeX | Tags: Francis-type Reversible Turbine, Hump instability, large partial flow conditions, Pump, Pump, Pump as Turbine, Pump Mode, unsteady flow pattern
@article{Yang2016,
title = {Study of Hump Instability Phenomena in Pump Turbine at Large Partial Flow Conditions on Pump Mode},
author = {Jun Yang and Shouqi Yuan and Giorgio Pavesi and Chun Li and Zhou Ye and Yuan Shouqi},
url = {http://www.cjmenet.com.cn/Jwk_jxgcxb/CN/10.3901/JME.2016.24.170},
doi = {10.3901/JME.2016.24.170},
issn = {0577-6686},
year = {2016},
date = {2016-01-01},
urldate = {2016-01-01},
journal = {Journal of Mechanical Engineering},
volume = {52},
issue = {24},
pages = {170},
abstract = {For middle- and high-specific speed pump turbines, the hump instability appearing at large partial flow conditions seriously restricts its stable operation range. These phenomena relate closely to the inner unsteady flow in pump turbine. We investigate the characterization of pressure fluctuation and the mechanism of unsteady flow by an experimental and numerical study of the unsteady flow occurring among the adjustable blades. For pump working at either full or part load conditions, two kinds of periodic pressure pulsations in the diffuser vane have been observed and analyzed. A hump instability appears only when the actual flow rate of head curve is 0.45-0.75 times of the designed value, and our frequency analysis further shows that its appearance is closely related to the two above pressure fluctuations.},
keywords = {Francis-type Reversible Turbine, Hump instability, large partial flow conditions, Pump, Pump, Pump as Turbine, Pump Mode, unsteady flow pattern},
pubstate = {published},
tppubtype = {article}
}
For middle- and high-specific speed pump turbines, the hump instability appearing at large partial flow conditions seriously restricts its stable operation range. These phenomena relate closely to the inner unsteady flow in pump turbine. We investigate the characterization of pressure fluctuation and the mechanism of unsteady flow by an experimental and numerical study of the unsteady flow occurring among the adjustable blades. For pump working at either full or part load conditions, two kinds of periodic pressure pulsations in the diffuser vane have been observed and analyzed. A hump instability appears only when the actual flow rate of head curve is 0.45-0.75 times of the designed value, and our frequency analysis further shows that its appearance is closely related to the two above pressure fluctuations.
