Study On Spiral-grooved Seals Performance Of Centrifugal Pump

The multistage centrifugal pump has a complex structure,large rotating speed and high pressure of medium,and the medium usually contains sand and other impurities.If the seals are made of ordinary seals,not only the service life is short,but also the installation and maintenance are inconvenient,and it must be replaced occasionally.The spiral-grooved seals can effectively solve these problems,and its ability to control leaks is stronger than ordinary seals.However,due to the great uncertainty of the application of spiral-grooved seals in multistage centrifugal pumps,the optimal parameters for spiral-grooved seals are also widely discussed.In order to solve these problems,the following research is done:Firstly,this paper takes the spiral-grooved seals at the front wear-ring clearance of the impeller of a multistage centrifugal pump as the research object.The steady flow of the Spiral-grooved seals under different parameters was simulated by the Fluent software.Taking the friction factor as the index to evaluate the leakage characteristics of the spiral-grooved seals,the influence of parameters on the performance of the spiral-grooved seals was studied,and the flow field distribution of the spiral-grooved seals under different parameters was analyzed.The conclusion is as follows: the friction factor of the spiral-grooved seals decreases with the increase of the axial reynolds number and tends to converge gradually.That is,the sealing performance of the spiral-grooved seals with the increase of the axial reynolds number.Under different axial reynolds number,with the increase of seal diameter,seal length,rotational speed and dynamic viscosity of medium,the friction factor of the spiral-grooved seals increases,the sealing performance improves,and the pressure difference between the two ends of the seal increases.The optimal spiral angle,relative groove width and relative groove depth exist under different axial reynolds numbers.The optimal spiral angle is 21.05 degrees,the optimal relative groove width is 0.5,and the optimal relative groove depth is 3.The friction factor of the spiral-grooved seals reaches the maximum under the optimal value.At this time,the seal performance is the best and the pressure difference between the two ends of the seals is the largest.Secondly,the steady flow of the centrifugal pump with annular seals,circumferential channel seals and spiral-grooved seals is simulated,to study the effect of the wear-ring clearance structure on the centrifugal pump performance and internal flow characteristics.The conclusion is as follows: when centrifugal pumps adopt annular seals,circumferential groove seals and spiral-grooved seals,the leakage of the wear-ring clearance decreases,while the volume efficiency,head,total efficiency,axial force and radial force increase.Compared with the annular seals,the leakage of the wear-ring of the centrifugal pump decreases by 21.65% and 25.13%,the volume efficiency increases by 1.02% and 1.18%,the head increases by 2.29% and 3.25%,the total efficiency increases by 3.87% and 5.32%,axial and radial forces have increased considerably,respectively,when the circumferential groove seals and the spiralgrooved seals are used.The pressure difference in the front chamber of centrifugal pump increases,the velocity gradient decreases,the number of vortices in the front chamber decreases,the scale increases,and the closer to the pressure chamber,the less obvious the shape of vortices.