Research on Hydraulic Characteristics of Inlet Pipeline of Pumping Station Based on Standard k-ε Turbulence Model

Abstract

【Background】 The flow velocity in the inlet pipeline does not meet the requirements of the specification and the flow pattern is turbulent of an irrigation pumping station in the lower reaches of the Yellow River. Hydraulic loss and uneven distribution of water flow field at the outlet of the inlet pipe (pump inlet), causing overpowered operation of the pump unit, cavitation and vibration of the pump, and harsh noise. In severe cases, the blades are broken and the pump unit cannot work, which poses a threat to the personal safety of the pump station staff, and urgently needs technical upgrading and transformation. 【Objective】 Aiming at the problems of the unreasonable layout of the inlet pipeline of a pumping irrigation pumping station in the lower reaches of the Yellow River, the water inlet pipeline of the pumping station was technically transformed in response to problems such as the deterioration of the water flow at the inlet of the pump, the fracture of the pump blades, the vibration of the pump unit, and the overload operation. 【Method】 The NS equation of three-dimensional incompressible fluid and the standard k-ε model were used to numerically simulate the hydraulic characteristics of the inlet pipeline before and after the transformation, and the flow velocity distribution and streamline distribution of different sections of the inlet pipeline under five flow rates were analyzed. Alos, the velocity distribution uniformity, pipeline hydraulic loss, pipeline vorticity distribution and vorticity value of the outlet (water pump inlet) section were analyced. 【Result】 After the transformation, the hydraulic loss of the inlet pipeline was reduced by 78.96% on average, and the maximum positive and negative vorticity values were reduced by 83%~84% on average; the flow pattern and vortex distribution of the inlet pipeline tended to be uniform, and the water flow in the inlet pipeline was stable. The average flow velocity is 1.57~1.93 m/s, which met the requirements of the specification; The uniformity of the flow velocity distribution of the outlet section of the inlet pipe increased by 4.48% on average, which effectively improves the pump inlet conditions. 【Conclusion】 The hydraulic characteristics of the inlet pipeline of the pumping station after the renovation have been improved, and the active power of each unit is reduced by 35 kW, which has obvious energy-saving effects, which can provide a reference for similar renovation projects.

Keywords

• inlet pipe
• numerical simulation
• hydraulic characteristics
• k-ε model