Study On The Effect Of Blade Unequal Spacing And Clocking Position On The Performance Of Series-parallel Centrifugal Pump

The series-parallel centrifugal pump is widely used in the ship field due to its multi-purpose and small space occupancy.Series parallel centrifugal pump is an important safety equipment for ships,so it's reliability and stability must be guaranteed,but the pressure pulsation caused by the rotor-stator interaction of the pump will directly affect the stability of the pump.Therefore,in this paper,a series-parallel pump is selected as the research object.Through the different design of impeller and guide vane,explore the effect of rotor-stator interaction on the pressure pulsation performance of the series-parallel pump.Based on CFD technology,model test and theoretical analysis,the hydraulic performance and pressure pulsation characteristics of series-parallel pump under blade unequal spacing and relative position of guide vane are studied.Based on the main design parameters of series-parallel centrifugal pump,the scheme design,three-dimensional modeling and grid division of the components are carried out;the simulation results are compared with the experimental data to verify the feasibility of numerical simulation,and then the simulation of the blade unequal spacing and the position of the guide vane is carried out;the influence of the change of component parameters on the hydraulic performance,internal flow characteristics and pressure pulsation characteristics of the series-parallel centrifugal pump is studied.The main conclusions are as follows:(1)Unequal spacing scheme has the effect of improving the efficiency.Under the rated condition,the efficiency is highest when the minimum angle distance is 56°.Too small angular spacing is not conducive to fluid flow,so the minimum angle spacing should be controlled in a reasonable range.(2)The change of the relative position between the guide vane and the tongue has effect on the external characteristics of series-parallel pump and the flow distribution in the parallel operation.Under rated condition,when the relative angle is 12° in parallel working the efficiency is highest,when the relative angle is 30° in series working the efficiency is highest.The flow ratio curve is similar to the efficiency curve under the parallel rated condition,which shows that the flow change has a great influence on the efficiency of the parallel operating condition.(3)The unequal distance blade has the effect of reducing the main frequency amplitude and dispersing pressure pulsation.In the guide vane,the amplitude of themain frequency is smaller and the new pulsation frequency is produced,it is beneficial to the stability of the pulsation.It is found that the frequency of pressure pulsation is determined by the axis frequency and the blade number,rather than the vane frequency.In the volute,the amplitude distribution in the volute is uniform and reasonable at the minimum angle distance of 56°.(4)The change of the relative position between guide vane and the tongue has a certain effect on the pressure pulsation of the series-parallel centrifugal pump.The position change of the guide vane only affects the time domain phase of the monitoring point in the impeller,and has little effect on the fluctuation amplitude,amplitude and pulsation frequency.The fluctuation amplitude and the main frequency amplitude of the monitoring point in the volute and the outlet are smaller under two working conditions when the relative angle between the guide vane and tongue is 12°.