| For centrifugal pump,good inflow is the important factors to guarantee the whole pump hydraulic performance,in actual operation of the centrifugal pump,however,there are often due to the limited space of inlet pipe bending,import reflux and non-uniform inflow prewhirl and so on,resulting in the contradiction between “uniform inflow in the process of design " and " non-uniform inflow in actual operation” to the centrifugal pump.In order to improve actual operation efficiency and safety stability of reference,promote centrifugal pump saving energy and reducing consumption to develop new ideas in the field of engineering application.the article based on the actual engineering application of double suction centrifugal pump,analysis the inflow non-uniform cases caused by inlet pipe bending,the internal flow characteristics of double suction pump.First of all,set up a double suction centrifugal pump pressure pulsation test bench,to test the external characteristic of uniform inflow conditions,and uses the high frequency dynamic pressure sensor to measuring and analyze the monitoring point of volute inlet and outlet pipe of the pressure pulsation;The model of double-suction centrifugal pump is simulated by the method of uniform inflow,and the simulation results are consistent with the experimental results.Comparing simulation results with the results of the experiment and found:(1)The external characteristic data obtained by the double-suction centrifugal pump is consistent with the trend of the data of external properties obtained by the numerical simulation;(2)The main frequency of the pressure pulsation in the volute is the leaf frequency,and it strongest in the septum;(3)Under the small flow condition,the pressure pulsation of the main frequency was 2.6 times.The simulation results are consistent with the experimental results.On the basis of this,the internal flow numerical simulation study of double suction centrifugal pump is carried out.Secondly,the non-uniform inflow pipeline is modeled and the double-suction centrifugal pump is calculated for non-uniform inflow.This paper analyzes the flow of non-uniformity,externality,internal and import and export section of the inlet flange.The results of the study show that:(1)When the double suction centrifugal pump runs under the non-uniform inflow pipeline,the pump head and efficiency are decreased,Horizontal pipe bending effect the performance of the pump is higher than the vertical pipe bending;(2)The non-uniform inflow of double suction centrifugal pump has a large effect on the flow velocity,static pressure and turbulent energy distribution of the impeller inlet and outlet cross section;(3)In the flow of horizontal pipe,the head and efficiency of the pump decrease.the largest decrease was 0.48 m and 1.02% respectively;(4)In the horizontal pipe inflow,double suction centrifugal pump impeller flow on both sides are differences,the differences within the impeller in only part of the flow channel;Under design conditions,on both sides of the double suction impeller flow nonuniformity of the impeller has a size of 50.2 N axial force;In the end,the double suction centrifugal pump in the non-uniform inflow condition is calculated,and the pressure pulse and axial force are analyzed respectively.The results of the study show that:(1)Non-uniform inflow condition caused mainly double-suction centrifugal pump shaft frequency pressure pulsation have risen sharply,with pressure impulses pressure pulsation rose slightly,and in the biggest rise in the every tongue location pulsation;(2)The flow difference between the vane and the vane does not cause a large change in the pressure pulse on both sides of the impeller;(3)Non-uniform inflow can significantly change the distribution of axial force of impeller and increase the amplitude of axial force pulse... |
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