| As a special centrifugal pump,disc pump relies on the viscous force between the fluid to transport the fluid.Adding a series of blade to smooth disc pump,the way of disc blade pump transforming energy has changed.Disc pump relies on the traction of viscous forces between fluids.While in disc blade pump,the centrifugal force generated by the blade is combined with the viscous force between the fluid,which changes the way that disc blade pump transforms energy.the head and efficiency of disc blade pump are much higher than smooth disc pump,which is widely used in oil,mining,slurry conveying and other industries.Existing study results have basically revealed the performance characteristics and internal flow characteristics of the disk pump,such as the radial velocity distribution.But the study of disc blade pump is not enough,especially about the internal flow mechanism.According the mature disc blade pump model,this study transformed the existing centrifugal pump model and designed disc blade pump test bench.The test bench is an open system.following work was carried out around the experimental platform:1.The experiment of disc blade pump performance have been carried out.Disc blade pump test bench is composed of water tank,electromagnetic flowmeter,gate valve,prototype pump and other testing equipment.It can adjust flow rate and rotating speed according frequency motor,gate type valve and electromagnetic flowmeter cooperation.The inlet and outlet of disc blade pump installed dynamic pressure senor,which can measure pressure.It can calculate the head according the pressure of inlet and outlet.The efficiency is calculated by the torque which is read by torque sensor.2.Disc blade pump performance have been analyzed.According the calculation of the experimental data,the performance curve of the vane disc pump is drawn,and the performance of the disc blade pump under different speeds and flow rate is analyzedAccording the experimental data,the main conclusion are as follows: The performance of the disc blade pump under the same size and operating conditions is lower than that of the general centrifugal pump.The downward trend of the disc blade pump’s head and efficiency is slower than that of the centrifugal pump and its performance is more stable.The theoretical head coefficient of disc blade pump increases with the development of rotational speed.The cavitation caused plummet of disc blade pump under high rotating speed and flow rate.In addition to experimental tests,numerical simulation study was carried out simultaneously.Radial velocity distribution and internal flow mechanism are obtained by getting data of velocity and analyzing distribution of pressure,streamline,turbulent kinetic energy,and other flow information.The main work is as follows1.The numerical calculation work of disc blade pump have been carried out.The model of numerical calculation is based on experimental model.The specific parameters of each part is measured by 3D scanner,vernier caliper,micrometer and other mapping instruments.The geometry was established according experimental prototype,and then the model was divided into structured grids by ICEM CFD.The choose of turbulence model referred to other study of numerical calculation and considered the factors such as calculation resources and calculation time.The boundary conditions of the numerical simulation were set based on the experimental operating environment,and the rough wall conditions were modified by reading relevant literature.2.Numerical calculation results of disc blade pump have been analyzed.The performance curve is draw by the results of calculation under different flow rate.Compared with the experiment,the numerical simulation results are reliable.By reading the numerical simulation results,the radial velocity distribution of disc blade pump under different flow channels and different positions were drawn and their distribution rules were analyzed.In order to studying internal flow mechanism,the internal flow field information,such as flow line distribution,pressure distribution and velocity distribution under different flow channels and different axial positions were analyzed.The influence of roughness was analyzed,according comparing performance curves,radial velocity distribution,turbulent kinetic energy,pressure,velocity,and other flow field information under different roughness.3.Boundary layer effects are used by disc blade pump to transform energy;however,the surface roughness directly influences boundary layer structure.Therefore,studying effect of surface roughness has theoretical guiding significance and practical engineering value.The rough wall condition was modified by reading related literature,and then the effects of roughness are analyzed by performance curves,radial velocity distribution,Flow field information such as turbulent kinetic energy,distribution of pressure and velocity.According numerical simulation results,the main conclusions of this study are as follows:1.Different radius position of the radial velocity distribution is different.The fluid flow development near the impeller entrance location is inadequate,because the effect of inlet fluid which is disorder.The distribution of boundary layer far from inlet is symmetrical about center section,and the radial velocity distribution of bladeless is about a parabolic distribution.In the same flow channel,the distribution of radial velocity at different positions is different,and there is radial backflow between two blades and the suction side.The radial velocity distribution in different flow channels which are symmetric is same.There is the vortex in the suction side,due to the influence of fluid flow around.The vortex influent radial velocity distribution.In axial direction,The fluid flow from blade part to bladeless part.2.The head and efficiency are decline as surface roughness developing.As flow rate increasing,the head and efficiency are decline in the same surface roughness.The increase of surface roughness has no effect on the flow structure in the blade part.It mainly increases the energy loss at the impeller wall,affects the energy transfer between the blade part and the bladeless part,influence the velocity distribution in the bladeless part.And then it affects the distribution of the radial velocity... |
