Research On The Correlation Between The Performance Characteristics And The Internal Flow Structure Of Vortex Pump Transporting Chemical Acid

Vortex pump is an excellent non-clogging pump.With the continuous development of industry and agriculture,it is widely used in complex fluid,such as sewage,mud,paper pulp and fluid containing impurities with vegetable crops,fish and shrimp shells.The scope of application of vortex pump have been further expanded,such as the transportation of chemical acid with a certain viscosity.At present,most of the research focuses on water and solid-liquid two-phase flow,and there is little research on the relationship between the performance of vortex pump to transport chemical acid liquid and the internal flow structure.Therefore,this paper will study the internal flow characteristics of vortex pumps in different viscosity media on the basis of numerical simulation,especially analyze the internal flow structure of vortex pumps,so as to further explore the internal flow characteristics of vortex pumps.In particular,the internal flow structure of the vortex pump is analyzed to further explore the internal flow characteristics of the vortex pump.The specific contents and conclusions are as follows:The 150WX-200-20 vortex pump is selected as the research object.This paper studies the external characteristics and internal flow characteristics of chemical acid with different viscosities,taking into account the influ ence of blade shape.First,the media of chemical acid with viscosity 0.01Pa·s and 2Pa·s are compared with water,and it is found that the viscosity has a greater influence on the internal flow characteristics.When the viscosity of the chemical acid incre ases,the head decreases,the shaft power increases,and the efficiency decreases,and its best efficiency point moves to a small flow operating point small flow.As the viscosity increases,the circulating flow is compressed in the axial direction,and it s position gradually moves to the side of the bladeless cavity close to the inlet domain,and the through flow gradually moves in the axial direction to the side close to the impeller domain.After the circulating flow is squeezed,the fluid in the impelle r area cannot be transported to the bladeless cavity,and a large number of fluid accumulates in the retraction cavity,which reduces the efficiency of the vortex pump.At the same time,the vortex distribution in the impeller domain changes.It gradually c hanges from the blade break point to the back face and the working face of the impeller.Secondly,a quantitative analysis of the circulating flow and through flow in the vortex pump is carried out.The best efficiency point is analyzed from three aspects:the position of the vortex core,the pressure gradient and the velocity gradient.When the vortex core position changes with section,at the best efficiency point the displacement is small,and its axial coordinate greater than zero,and the same time,the value of l is the smallest.In the radial direction,the circulating flow vortex core is located close to the impeller hub.The position of the through-flow vortex core is stable at the center of the diffusion section in the radial direction,and the displacement is uniform on the A1～A4 section in the axial direction,and the A5～A8 section is stable at the center of the bladeless cavity.The pressure gradient of the circulating flow and the through flow decreases with the increase of viscosity on the best efficiency point,and the best efficiency is when it is at the extreme point under the same viscosity.The change of viscosity changes the direction of the through-flow velocity gradient,from first increasing and then decreasing to first decreasing and then increasing.For circulating flow,the efficiency is highest when the difference between the maximum velocity gradient and the minimum velocity gradient is the smallest.Finally,the four different blade shapes are numerically calculated using the fluid chemical acid with viscosity 1.5Pa·s.Based on the above research,further analysis of the efficiency change caused by the blade shape.When the viscosity is 1.5Pa·s,the order of blade efficiency is R30L30,L30R30,R30,Curl60.The change of the blade type causes the phenomenon that the l_min section is not the A1 section in the bladeless cavity,which changes the position of the vortex core of the circulating flow,thereby reducing the efficiency of the pump.When the shape of the blad e changes,the circulating flow range is increasing in the radial direction.It will affect the vortex of the fluid flow at the inlet section,which will increase the energy loss and reduce the efficiency of the vortex pump.In different blade types,the g reater the difference between the velocity gradient and the pressure gradient on the cross section of the best efficiency point,the higher the efficiency.Based on the study of the external characteristics and internal flow structure of the cyclone pump u nder chemical acid,changing the internal flow structure of the vortex pump is great significance to improving the efficiency of the vortex pump when transporting chemical acid.