Study On Optimization Design And Model Test Of Pumping Device Of Paihekou Pumping Station

The large-scale low head pump station is widely used in China and has played an indelible role in ensuring the prosperity of the economy,the people's happy life,and the social harmony and stability.Paihekou Pumping Station is a cascade pumping station for the Jianghuai-Huaihe River project in Anhui Province.The lifting range of this station is 1.4m-5.3m,and the total design flow is 301.5m3/s.It is a pump station with low lift and large flow rate.The hydraulic characteristics of the water flow in and out of the station have a crucial influence on the efficient operation of the pump station..In this paper,the study of the pumping station project is carried out.The physical characteristics of the pump device are studied by physical model test and three-dimensional flow numerical simulation.The main research contents and results are as follows:(1)Design pump unit model tests.According to the design of the Paihekou Pumping Station Project,through the selection coefficient method and the same type of algorithm,the water models of the TJ04-ZL-06 and TJ04-ZL-19 were compared and selected to better suit the TJ04-ZL-06 hydraulic model.The measurement methods for the basic parameters such as model making process and flow rate,and the test methods for energy characteristics such as energy,cavitation,flyaway speed,and pulsation pressure were designed.(2)The basic theory of numerical simulation was elaborated,and the boundary conditions and grid division methods used in the calculation of the flow field in the inlet and outlet flow channels were determined.The axial flow velocity distribution uniformity,flow deviation angle,hydraulic loss and drag coefficient were selected as the input.Hydraulic flow performance evaluation indicators,select hydraulic loss and resistance coefficient as hydraulic performance evaluation indicators of the outlet flow.(3)The numerical simulation results of the preliminary scheme of inlet and outlet flow passages show that the elbow inlet passage of the Paihekou pumping station can provide an ideal inlet flow pattern for the inlet of the pump impeller;the mainstream of the flow in the straight section of the outlet channel is biased to the left There is a large vortex zone on the right side of the flow channel and on the lower left side of the isolation pier.The loss of the water head is large,which has a great influence on the energy performance of the pump device.The results of the preliminary scheme test show that the flow requirements of the pump device of the Submarine Pumping Station can be met,but the device efficiency index can only reach the general level.When the blade angle is 0° and the design head is 4.8m,the flow rate is 37.75m3/s,which meets the design flow rate.The efficiency of the equipment is 72.65%,and the efficiency level is general.When designing the head is 4.8m and +2°,the critical NPSH margin is 9.29m,and the water pump will not produce hazardous cavitation;the blade angle-6° unit flying speed 248.8 and the maximum row head 5.3m fly speed 184.74r/min,equivalent to 1.35 times the rated speed,will not cause damage to the pump unit;under the condition of blade angle-6°,the pressure pulsation frequency is 0.14ms,the maximum amplitude is +5cm,-5.7cm,and there will be no pressure pulsation hazard.(4)The hydraulic performance of inlet and outlet flow passages was optimized.Through comparison and selection of the schemes,the inlet flow passages were optimized for smooth water flow,more uniform contraction,and more uniform flow velocity distribution at the outlet of the flow channel.Turn to an orderly,moderately diffused solution 4.Subject to experimental conditions,the original elbow inlet flow path and outlet flow path optimization scheme 4 was used to carry out the pump device model test.The efficiency of the device under design conditions was between 76.43%and 77.14%,verifying the accuracy of the numerical simulation.The rationality of the preferred solution.The model test of the pump device and the numerical simulation of the flow channel in the Paihekou pump station carried out in this paper are numerical simulation to guide the model test and the model test verifies the accuracy of the numerical simulation.Through the optimization of the outlet flow channel,the efficiency of the pump device is effectively improved,which provides an important basis for the construction of the Pakoukou Pumping Station Project and is of great significance for ensuring the safety,efficiency,and stable operation of the project.It is also similar for the future.Pumping station construction provides a reference.