Multi-objective shape optimization of siphon outlet in pumping station considering two-phase flow

Abstract

The siphon outlet is widely used in pumping stations due to its reliable and convenient cut-off performance. Long siphoning time or high hydraulic loss caused by the inappropriate design of the siphon outlet can significantly affect the safety of stations. The air compressibility volume-of-fluid (VOF) method is conducted to simulate the two-phase flow in the siphoning formation process at the design points selected by the optimal Latin hypercube design (OLHD), the results of which show good agreement with the experimental data. In this work, the siphoning time and hydraulic loss coefficient are selected as the objective functions, and a multi-objective shape optimization strategy is proposed for the siphon outlet in conjunction with the response surface method (RSM). This optimization strategy can not only reconcile conflicting objective functions but also obtain the effect and interaction of design variables. Sensitivity analysis on the constructed response surface models indicates that among three design variables, the aspect ratio has the greatest effect on the objective functions, the descending angle has the second greatest effect, and the ascending angle has almost no effect. Compared with the original design, the hydraulic loss coefficient and siphoning time of the optimized design are reduced by 2.95% and 26.76%, respectively. A higher vorticity magnitude and more uniform outflow are created in the optimized design, which results in the improvement of hydraulic performance.

Two phase flow evaporative cooling technology for wind turbine cabin group

“…In the field of energy power generation, China currently mainly relies on thermal power generation and hydroelectric power generation, which account for more than 90% of the total power generation capacity. [1]Three quarters of the electricity comes from coal, and only China burns over 1.4 Gt of coal annually for power generation. In addition to fossil fuels such as coal, the Earth also has abundant renewable energy sources such as wind and solar energy.…”

“…During the development of wind power, there are often cases of major accidents such as malfunctions, shutdowns, and even fires caused by overheating of high-power components of wind turbines, such as generators, gearboxes, frequency converters, and control cabinets. [1]The development of new cooling technologies is not only of great help to the future development of wind power generation, but also has significant economic and social benefits. As a commonly used thermal management method, existing wind turbines mainly use air-cooled and liquid cooled technologies.…”

Time–frequency signal analysis of flow pulsation in siphon outlet conduit based on HHT considering the pump‐conduit interaction

“…There may also be a large hydraulic loss of the flow channel during the siphon process, a high head during the pump operation, causing vibration of the unit, excessive noise, and other adverse hydraulic phenomena, which cause great harm to the safety and stability of the project. 1 The internal flow pulsation of the SOC under the hydraulic coupling of the pump and the flow conduit is thus of great theoretical relevance and engineering practical benefit.…”

“…In the actual pumping station project, if the design is not considered properly or the influence of external factors such as water level and flow rate, the SOC may take a long time to form a stable siphon flow or cannot realize the siphon. There may also be a large hydraulic loss of the flow channel during the siphon process, a high head during the pump operation, causing vibration of the unit, excessive noise, and other adverse hydraulic phenomena, which cause great harm to the safety and stability of the project 1 . The internal flow pulsation of the SOC under the hydraulic coupling of the pump and the flow conduit is thus of great theoretical relevance and engineering practical benefit.…”