Research On Influencing Factors Of Dynamic Sealing Capability And Self-priming Performance Of Vertical Self-priming Pump

Self-priming pump is a kind of special centrifugal pump equipment,which is widely used in industrial and agricultural production and life.Self-priming performance is an important indicator for evaluating the performance of self-priming pumps.Based on my country’s requirements for environmental protection and sustainable development,higher requirements are put forward for the hydraulic performance and self-priming performance of self-priming pumps.The auxiliary impeller is the rotating moving part of the dynamic sealing structure of the vertical sealless self-priming pump.The geometric parameters of the sealing cavity are one of the important indicators that affect the dynamic sealing capacity of the self-priming pump.The impeller is used as the energy conversion structure of the self-priming pump,and the position of the impeller inlet and the clearance of the front orifice have a significant effect on the self-priming performance of the self-priming pump.Therefore,this paper studies the influence of the geometric parameter changes of the dynamic seal structure of the self-priming pump on the dynamic sealing performance of the self-priming pump,and the influence of the geometric parameter changes of the impeller on the self-priming performance of the self-priming pump.The specific research content is as follows:1.The influence of the geometric parameter changes of the dynamic seal structure of the vertical sealless self-priming pump on the sealing abilityIn order to reduce the energy loss of the sealing device of the self-priming pump and improve the overall efficiency of the self-priming pump,the orthogonal test method is used to optimize the design of the dynamic sealing structure while ensuring the structural parameters of other hydraulic components remain unchanged.In order to study the influence of the change of dynamic seal structure parameters on the sealing ability,according to the production and actual application of the self-priming pump,three changing factors of the auxiliary impeller blade form,the number of blades and the size of the exhaust hole of the seal cavity are selected,and each factor is selected For the three level variables,according to the L9(3~3)orthogonal test scheme,different schemes are designed.Numerical calculation results show that:in the case of meeting the requirements of self-priming pump dynamic sealing,the blade structure of the auxiliary impeller has a greater influence on the dynamic sealing ability,and the number of blades and the size of the exhaust hole have a relatively large influence on the dynamic sealing ability.small.Therefore,in the design of the dynamic seal device of the vertical non-sealed self-priming pump and the selection of the structural geometric parameters,the use of the radial straight blade structure,the appropriate number of blades and the exhaust hole of the sealed cavity can make the dynamic seal structure have a good sealing ability.,To a certain extent,the overall efficiency of the self-priming pump has been improved.2.Research on the influence of the position of the inlet edge of the impeller blade on the self-priming performance of the self-priming pumpIn order to study the influence of the position change of the impeller inlet on the gas-liquid mixing ability of the self-priming pump impeller during the self-priming process,and to ensure that other geometric parameters of the self-priming pump remain unchanged,a total of 5 different impellers were designed on the basis of the original impeller model.Model scheme.Comparing and analyzing the indefinite constant value of different model schemes,the calculation results show that the position of the impeller inlet side is swept forward from the position of the rear cover to the outlet,which can make the impeller inlet side work to load the fluid in time,which can effectively improve the self-priming pump in self-priming.The gas-liquid mixing ability in the exhaust stage shortens the self-priming completion time;the forward sweep angle of the impeller inlet has a linear effect on the external characteristics.Within a certain range,the forward sweep of the inlet has little effect on the head and efficiency of the self-priming pump,But the current sweeping more than a certain angle will significantly reduce the head and efficiency;under the rated conditions,when the impeller inlet side is swept forward at a certain angle of 10°,the self-priming time can be shortened by 25%compared with the original model self-priming pump,and the self-priming performance is obviously obtained.improve.3.Research on the influence of geometric parameters of the impeller front ring on the self-priming performance of the self-priming pumpIn order to study the influence of the geometric parameters of the impeller front orifice on the performance of the self-priming pump,20 different designs were designed on the basis of the original model by changing the value of the width l and the gap d of the front orifice while ensuring that other geometric parameters remain unchanged.The impeller scheme of,through the calculation of constant constant value and the calculation of non-definite constant value,respectively,the comparative analysis is carried out.The pressure change in the impeller of the self-priming pump is compared and analyzed by steady calculation.Through the monitoring and analysis of the gas content at the outlet position of different model schemes,the self-priming completion time of the self-priming pump of different model schemes is obtained.Through comparative analysis,the distribution of the gas-liquid two-phase inside the self-priming pump at different times can be obtained.Situation and the changing law of self-priming time under different schemes.Numerical calculation results show that the influence of the width and clearance of the front mouth ring on the self-priming performance of the self-priming pump is linear;the increase in the pressure difference between the inlet and outlet of the front mouth ring will increase the head and efficiency of the self-priming pump;The effect of suction performance is positively correlated,and the change of the front mouth ring gap is negatively correlated to the effect of self-priming performance.