The vortex pump is suitable for salt solution transportation.But the salt-out flow mechanism in the pump has not been understood fully.Salt-out layer formation and growth rate are closely related to crystal particle m...The vortex pump is suitable for salt solution transportation.But the salt-out flow mechanism in the pump has not been understood fully.Salt-out layer formation and growth rate are closely related to crystal particle motion and concentration distribution.Study on the particle hydrodynamic characteristics in the pump volute becomes a key problem,because the crystal particles are mainly distributing in this zone after they enter the pump.Phase Doppler particle analyzer(PDPA)is used to measure the two-phase flow field in a model pump volute to get more understanding about the salt-out phenomenon.The crystal particle velocities are obtained in all three peripheral,radial and axial directions.Particle size and particle number density(PND)measurements are also performed in the experiment.Results are presented and discussed along the radial direction under different pump operating conditions,as well as various axial measurement positions.It is found that particle velocity gradient of peripheral component varies with the pump discharge.There is a turning point of relation between peripheral velocity component and discharge.Radial flow velocity curves look like a saddle shape and velocity magnitudes are changing greatly with the discharge.The non-equilibrium velocity feature between liquid and solid phase on this direction is also remarkable.Particles flow into the impeller at radial position R〈I,and the axial velocity component increases in this region.The particle size curve shows an open-up parabola distribution.The largest particles are distributing near the casing peripheral wall.As flow rate increases,accordingly PND increases.It also grows up in the axial-outward direction towards the suction cover.Crystal particle aggregation phenomenon can be revealed from the analysis of particle size and PND distribution,and the aggregation region is determined as well.Research results are helpful for optimal design of this kind of pump preventing salt-out.展开更多
In order to reduce pressure pulsation of vortex pumps,the mantis shrimp was chosen as biological prototype and a bionic engineering model was developed from its abdominal segment grooves.Bionic mantis shrimp groove vo...In order to reduce pressure pulsation of vortex pumps,the mantis shrimp was chosen as biological prototype and a bionic engineering model was developed from its abdominal segment grooves.Bionic mantis shrimp groove volute vortex pump models with different numbers of grooves were developed,and numerical simulation methods were used to calculate the models to study the effects of the volute grooves on the pressure pulsation of a vortex pump.The results show that a bionic groove volute could effectively improve the pressure pulsation of a vortex pump outlet,and reduce the pressure pulsation around the pump’s tongue and other internal points.The pressure pulsation under different conditions is impacted by shaft frequency and blade frequency.The bionic groove structure has little effect on the external characteristics of the pump,but could improve the static pressure,velocity distribution,and vortex structure of the flow field.Additionally,pressure pulsation of the whole vortex pump is reduced.展开更多
In order to study influence of tongue clearance on the hydraulic performance of double support vortex pump,three dimensional flow model with symmetric variable size tongue clearance was established by changing section...In order to study influence of tongue clearance on the hydraulic performance of double support vortex pump,three dimensional flow model with symmetric variable size tongue clearance was established by changing section parameter of tongue clearance,and applied to numerically simulate the steady inner flow in a vortex pump based on fixed working conditions and impeller through ANSYS FLUENT.The numerical results show the influence of tongue channel with two sections(non-uniform and uniform sections)on flow field characteristics in vortex pump.Firstly,the variation of tongue channel section changes the vortex structure distribution in circumferential flow channel.Specifically the spiral forward vortex structure in the circumferential direction shifts to large radius side with increasing tongue width.Secondly,the circumferential velocity gradient and axial pressure gradient both diminish with the increase of the tongue section,and the inlet/outlet pressure difference and velocity distribution also reduce with increasing tongue channel section.Finally,for vortex pump with non-uniform section of tongue channel,the head diminishes and the efficiency remains constant approximately with the increase of the tongue width,while the head and the efficiency both diminish for uniform section of tongue channel.展开更多
Flow passages in vortex pumps usually have rough walls.Precise consideration of wall roughness is an important issue in pump flow simulations.Numerical studies of the effects of wall roughness on the performance of vo...Flow passages in vortex pumps usually have rough walls.Precise consideration of wall roughness is an important issue in pump flow simulations.Numerical studies of the effects of wall roughness on the performance of vortex pumps are quite rare,especially with different interface models.Turbulent flows of water in a vortex pump with a specific speed of 76 are simulated using 1/8 and whole impeller fluid domains with rough walls,using the three-dimensional Reynolds-averaged Navier-Stokes equations,the standard k-εmodel,and a scalable wall function in Ansys CFX 2019 R2.Equivalent sand grain roughnesses k_(s)=0.586 and 9.38μm are determined for the chamber casing,volute,and suction pipe,and k_(s)=18.47 and 36.94μm for the impeller by using the arithmetic average roughness Ra of the materials used in the pump and the correlation between k_(s)and Ra given in the literature.The mixing loss along the interface between impeller and volute in the transient rotor model is determined.The rates of change of the head,shaft-power,and efficiency of the pump due to wall roughness are calculated.The transient rotor model with whole impeller domain and the frozen rotor model with 1/8 impeller domain for rough walls with Ra=0.1μm in the suction pipe,volute,and chamber and 3.2μm in the impeller give the most accurate predictions of pump performance compared with experimental data.The transient rotor model with whole impeller domain gives more accurate predictions of pump performance than the frozen rotor model with 1/8 impeller domain.The mixing loss rises quickly at high flow rates.The transient rotor model with whole impeller domain gives plausible predictions of the rates of change.展开更多
Based on the standard k-ε turbulence model and the RANS equations, thefinite volume method and the SIMPLE algorithm were adopted to carry out the three-dimensionalviscous numerical simulation of the internal flow wit...Based on the standard k-ε turbulence model and the RANS equations, thefinite volume method and the SIMPLE algorithm were adopted to carry out the three-dimensionalviscous numerical simulation of the internal flow within a vortex pump in double reference frames.According to the results of numerical simulation, the internal flow in the vortex pump was analyzed,and the calculated results of blade surface pressure of the impeller were compared withexperimental results. The maximum relative error is 6.6% between calculated value and experimentalvalue of the pump head under operation conditions.展开更多
Based on the gas-liquid two-phase mixture transportation test,the k-c-A;turbulence model was applied to simulate the two-phase turbulent flow in a vortex pump.By comparing the simulation and experiment results,inner f...Based on the gas-liquid two-phase mixture transportation test,the k-c-A;turbulence model was applied to simulate the two-phase turbulent flow in a vortex pump.By comparing the simulation and experiment results,inner flow features were revealed.The bubbles in the channel distribute mainly at the pressure side of the blades,and the aggregation degree of the bubbles is enhanced with an increase in inlet gas volume fraction.Experimental results indicate that the influence of the gas phase on vortex pump performance is small when the gas volume fraction is less than 10%.When the gas volume fraction contiuuously increases to 15%,the characteristic curves abruptly drop due to the gas blocking phenomenon.展开更多
The vortex pump has increasingly become an important alternative or supplement to the centrifugal pump, the positive displacement pump and the diffusion pump due to its capacity of developing a high head at a small fl...The vortex pump has increasingly become an important alternative or supplement to the centrifugal pump, the positive displacement pump and the diffusion pump due to its capacity of developing a high head at a small flow rate within a single stage. However, the vortex pumps with various blade shapes such as the twisted blades or the 3-D blades are not well studied. In this paper, some new concepts of the 2-D and 3-D corner blades are introduced for the design of the vortex pumps. The mechanism behind the effect of the corner blade shapes on the pump hydraulic performance is numerically investigated and elucidated in terms of the internal vortex structures. The results show that both 2-D and 3-D forward corner blades can induce stronger well-organized longitudinal vortices as well as smaller axial and radial vortices within the impeller blade passage, which benefit a higher pump head and a higher efficiency in comparison with the traditional radial straight blade. This study provides useful guidelines for the design of advanced vortex pumps.展开更多
In order to study the mechanism of the vortex generation at the bottom of the pump sump below the flare tube,twenty pressure pulsation monitoring points were arranged at the bottom of the pump sump below the flare tub...In order to study the mechanism of the vortex generation at the bottom of the pump sump below the flare tube,twenty pressure pulsation monitoring points were arranged at the bottom of the pump sump below the flare tube,and the pressure fluctuation experiments were carried out under different flow conditions.The experimental results show that the frequency of pressure fluctuation at the bottom of the pump sump is twice of the rotational frequency of the impeller blade.The vortex below the flare tube is easy to generate under the large flow conditions and mainly concentrates at the right front position below the flare tube.The position of the vortex occurring is corresponding to the position of the low-pressure region below flare tube.展开更多
The performance of an annular jet pump( AJP) is determined by its area ratio A( ratio of cross sectional area of throat and annular nozzle) and flow rate ratio q( ratio of primary and secondary flow rate,Qs/Qj),while ...The performance of an annular jet pump( AJP) is determined by its area ratio A( ratio of cross sectional area of throat and annular nozzle) and flow rate ratio q( ratio of primary and secondary flow rate,Qs/Qj),while the nozzle lip thickness is neglected in the present studies. This paper presents a study on the effect of the thickness on the flow field and performance of an AJP with A = 1. 75. With the increasing flow rate ratio and nozzle lip thickness,a small vortex forms at the nozzle lip and keeps on growing. However,as the flow rate ratio or nozzle lip thickness is extremely low,the vortex at the lip vanishes thoroughly. Moreover,the recirculation width varies conversely with the nozzle lip thickness when the flow rate ratio q ≤ 0. 13. While the deviation of the recirculation width with different nozzle lip thickness is negligible with q ≥ 0. 13. Additionally the existence of nozzle lip hinders the momentum exchange between the primary and secondary flow and leads to a mutation of velocity gradient near the nozzle exit,which shift the recirculation downstream. Finally,based on the numerical results of the streamwise and spanwise vortex distributions in the suction chamber, the characteristics of the mixing process and the main factors accounting for the AJP performance are clarified.展开更多
The rotary jet pumps, namely the pitot pumps, are composed of the rotating casing with the impeller channels and the stationary pick-up tube for discharging, are known as the one of high pressure pumps in the U.S. mar...The rotary jet pumps, namely the pitot pumps, are composed of the rotating casing with the impeller channels and the stationary pick-up tube for discharging, are known as the one of high pressure pumps in the U.S. market. The pumps, however, have been prepared experientially, because of poor knowledge for the flow conditions and the pump performances. Then, this paper discusses the pump performances and the internal flow conditions in the rotating casing. Three types of the pick-up tube were prepared for the experiments to know the pump performances and the flow conditions in the rotating casing. The flow in the rotating casing is nearly in the forced vortex type and gives the higher pressure at the pick-up tube inlet. The more cross-sectional area of the pick-up tube channel is large, the more head and discharge are higher with excellent efficiency. Moreover, the authors confirmed that the secondary flow runs toward the rotating center at the wake flow region behind the pick-up tube.展开更多
基金supported by National Natural Science Foundation of China(Grant No.50476068)Jiangsu Provincial Postgraduate Cultivation Innovation Project of China(Grant No.CX07B_093z)
文摘The vortex pump is suitable for salt solution transportation.But the salt-out flow mechanism in the pump has not been understood fully.Salt-out layer formation and growth rate are closely related to crystal particle motion and concentration distribution.Study on the particle hydrodynamic characteristics in the pump volute becomes a key problem,because the crystal particles are mainly distributing in this zone after they enter the pump.Phase Doppler particle analyzer(PDPA)is used to measure the two-phase flow field in a model pump volute to get more understanding about the salt-out phenomenon.The crystal particle velocities are obtained in all three peripheral,radial and axial directions.Particle size and particle number density(PND)measurements are also performed in the experiment.Results are presented and discussed along the radial direction under different pump operating conditions,as well as various axial measurement positions.It is found that particle velocity gradient of peripheral component varies with the pump discharge.There is a turning point of relation between peripheral velocity component and discharge.Radial flow velocity curves look like a saddle shape and velocity magnitudes are changing greatly with the discharge.The non-equilibrium velocity feature between liquid and solid phase on this direction is also remarkable.Particles flow into the impeller at radial position R〈I,and the axial velocity component increases in this region.The particle size curve shows an open-up parabola distribution.The largest particles are distributing near the casing peripheral wall.As flow rate increases,accordingly PND increases.It also grows up in the axial-outward direction towards the suction cover.Crystal particle aggregation phenomenon can be revealed from the analysis of particle size and PND distribution,and the aggregation region is determined as well.Research results are helpful for optimal design of this kind of pump preventing salt-out.
基金Projects(51779226,51476144)supported by the National Natural Science Foundation of ChinaProject(2017C31025)supported by Zhejiang Province Department Public Welfare Industrial Projects,China+1 种基金Project(2016M601736)supported by Postdoctoral Science Foundation of ChinaProject(1601028C)supported by Postdoctoral Research Funding Plan in Jiangsu Province,China
文摘In order to reduce pressure pulsation of vortex pumps,the mantis shrimp was chosen as biological prototype and a bionic engineering model was developed from its abdominal segment grooves.Bionic mantis shrimp groove volute vortex pump models with different numbers of grooves were developed,and numerical simulation methods were used to calculate the models to study the effects of the volute grooves on the pressure pulsation of a vortex pump.The results show that a bionic groove volute could effectively improve the pressure pulsation of a vortex pump outlet,and reduce the pressure pulsation around the pump’s tongue and other internal points.The pressure pulsation under different conditions is impacted by shaft frequency and blade frequency.The bionic groove structure has little effect on the external characteristics of the pump,but could improve the static pressure,velocity distribution,and vortex structure of the flow field.Additionally,pressure pulsation of the whole vortex pump is reduced.
基金the National Natural Science Foundation of China(No. 51575420)the Local Service Special Project of the Education Department of Shaanxi Province, China (No. 14 JF011)+1 种基金the Special Fund Project of Major Science and Technology Innovation of Shaanxi Province, China (No. 2017ZKC0124, No. 2018TP-17)Xi’an Science and Technology project, China (No. 201805032YD10CG16(5)) for the support
文摘In order to study influence of tongue clearance on the hydraulic performance of double support vortex pump,three dimensional flow model with symmetric variable size tongue clearance was established by changing section parameter of tongue clearance,and applied to numerically simulate the steady inner flow in a vortex pump based on fixed working conditions and impeller through ANSYS FLUENT.The numerical results show the influence of tongue channel with two sections(non-uniform and uniform sections)on flow field characteristics in vortex pump.Firstly,the variation of tongue channel section changes the vortex structure distribution in circumferential flow channel.Specifically the spiral forward vortex structure in the circumferential direction shifts to large radius side with increasing tongue width.Secondly,the circumferential velocity gradient and axial pressure gradient both diminish with the increase of the tongue section,and the inlet/outlet pressure difference and velocity distribution also reduce with increasing tongue channel section.Finally,for vortex pump with non-uniform section of tongue channel,the head diminishes and the efficiency remains constant approximately with the increase of the tongue width,while the head and the efficiency both diminish for uniform section of tongue channel.
文摘Flow passages in vortex pumps usually have rough walls.Precise consideration of wall roughness is an important issue in pump flow simulations.Numerical studies of the effects of wall roughness on the performance of vortex pumps are quite rare,especially with different interface models.Turbulent flows of water in a vortex pump with a specific speed of 76 are simulated using 1/8 and whole impeller fluid domains with rough walls,using the three-dimensional Reynolds-averaged Navier-Stokes equations,the standard k-εmodel,and a scalable wall function in Ansys CFX 2019 R2.Equivalent sand grain roughnesses k_(s)=0.586 and 9.38μm are determined for the chamber casing,volute,and suction pipe,and k_(s)=18.47 and 36.94μm for the impeller by using the arithmetic average roughness Ra of the materials used in the pump and the correlation between k_(s)and Ra given in the literature.The mixing loss along the interface between impeller and volute in the transient rotor model is determined.The rates of change of the head,shaft-power,and efficiency of the pump due to wall roughness are calculated.The transient rotor model with whole impeller domain and the frozen rotor model with 1/8 impeller domain for rough walls with Ra=0.1μm in the suction pipe,volute,and chamber and 3.2μm in the impeller give the most accurate predictions of pump performance compared with experimental data.The transient rotor model with whole impeller domain gives more accurate predictions of pump performance than the frozen rotor model with 1/8 impeller domain.The mixing loss rises quickly at high flow rates.The transient rotor model with whole impeller domain gives plausible predictions of the rates of change.
文摘Based on the standard k-ε turbulence model and the RANS equations, thefinite volume method and the SIMPLE algorithm were adopted to carry out the three-dimensionalviscous numerical simulation of the internal flow within a vortex pump in double reference frames.According to the results of numerical simulation, the internal flow in the vortex pump was analyzed,and the calculated results of blade surface pressure of the impeller were compared withexperimental results. The maximum relative error is 6.6% between calculated value and experimentalvalue of the pump head under operation conditions.
基金supported by the National Natural Science Foundation of China(No50879080,No 50609025 and No 50735004)Zhejiang Provincial Key Science Foundation of China(No2008C01024-1 and No2008C21023)
文摘Based on the gas-liquid two-phase mixture transportation test,the k-c-A;turbulence model was applied to simulate the two-phase turbulent flow in a vortex pump.By comparing the simulation and experiment results,inner flow features were revealed.The bubbles in the channel distribute mainly at the pressure side of the blades,and the aggregation degree of the bubbles is enhanced with an increase in inlet gas volume fraction.Experimental results indicate that the influence of the gas phase on vortex pump performance is small when the gas volume fraction is less than 10%.When the gas volume fraction contiuuously increases to 15%,the characteristic curves abruptly drop due to the gas blocking phenomenon.
基金Project supported by the National Key Research and Development Project of China(Grant No.2016YFB0200903)the National Natural Science Foundation of China(Grant No.51776154)
文摘The vortex pump has increasingly become an important alternative or supplement to the centrifugal pump, the positive displacement pump and the diffusion pump due to its capacity of developing a high head at a small flow rate within a single stage. However, the vortex pumps with various blade shapes such as the twisted blades or the 3-D blades are not well studied. In this paper, some new concepts of the 2-D and 3-D corner blades are introduced for the design of the vortex pumps. The mechanism behind the effect of the corner blade shapes on the pump hydraulic performance is numerically investigated and elucidated in terms of the internal vortex structures. The results show that both 2-D and 3-D forward corner blades can induce stronger well-organized longitudinal vortices as well as smaller axial and radial vortices within the impeller blade passage, which benefit a higher pump head and a higher efficiency in comparison with the traditional radial straight blade. This study provides useful guidelines for the design of advanced vortex pumps.
基金China Nature Science Funds(51279173)“The 12th Five-year”Key Project of National Science and Technology Support Plan(2015BAD20B01)Jiangsu Water Conservancy Science and Technology Project(2017031)
文摘In order to study the mechanism of the vortex generation at the bottom of the pump sump below the flare tube,twenty pressure pulsation monitoring points were arranged at the bottom of the pump sump below the flare tube,and the pressure fluctuation experiments were carried out under different flow conditions.The experimental results show that the frequency of pressure fluctuation at the bottom of the pump sump is twice of the rotational frequency of the impeller blade.The vortex below the flare tube is easy to generate under the large flow conditions and mainly concentrates at the right front position below the flare tube.The position of the vortex occurring is corresponding to the position of the low-pressure region below flare tube.
基金Sponsored by the National Natural Science Foundation of China(Grant No.51179134)the National Key Basic Research Program of China(Grant No.2014CB239203)Program for New Century Excellent Talents in University(Grant No.NCET-12-0424)
文摘The performance of an annular jet pump( AJP) is determined by its area ratio A( ratio of cross sectional area of throat and annular nozzle) and flow rate ratio q( ratio of primary and secondary flow rate,Qs/Qj),while the nozzle lip thickness is neglected in the present studies. This paper presents a study on the effect of the thickness on the flow field and performance of an AJP with A = 1. 75. With the increasing flow rate ratio and nozzle lip thickness,a small vortex forms at the nozzle lip and keeps on growing. However,as the flow rate ratio or nozzle lip thickness is extremely low,the vortex at the lip vanishes thoroughly. Moreover,the recirculation width varies conversely with the nozzle lip thickness when the flow rate ratio q ≤ 0. 13. While the deviation of the recirculation width with different nozzle lip thickness is negligible with q ≥ 0. 13. Additionally the existence of nozzle lip hinders the momentum exchange between the primary and secondary flow and leads to a mutation of velocity gradient near the nozzle exit,which shift the recirculation downstream. Finally,based on the numerical results of the streamwise and spanwise vortex distributions in the suction chamber, the characteristics of the mixing process and the main factors accounting for the AJP performance are clarified.
文摘The rotary jet pumps, namely the pitot pumps, are composed of the rotating casing with the impeller channels and the stationary pick-up tube for discharging, are known as the one of high pressure pumps in the U.S. market. The pumps, however, have been prepared experientially, because of poor knowledge for the flow conditions and the pump performances. Then, this paper discusses the pump performances and the internal flow conditions in the rotating casing. Three types of the pick-up tube were prepared for the experiments to know the pump performances and the flow conditions in the rotating casing. The flow in the rotating casing is nearly in the forced vortex type and gives the higher pressure at the pick-up tube inlet. The more cross-sectional area of the pick-up tube channel is large, the more head and discharge are higher with excellent efficiency. Moreover, the authors confirmed that the secondary flow runs toward the rotating center at the wake flow region behind the pick-up tube.
