PosterPresentations.com A1 Template V5
2
RESEARCHPOSTERPRESENTATIONDESIGN© 2012 www.Pos terPresentations.com The compl ex intern al flow of water of centr ifuga l pump through impeller and dif fus er can be pr edic ted with the hel p of compu tati onal flui d dyna mi c, it facilitating the product development process of pumps. In this thesis a CFD code is used to solve the governing equation of flow field. A 2-D simulation of turbulent fluid flow is pres ented to visua lize the flow in centr ifuga l pump, includin g the pres sure and velocity distributi ons. The standa rd k-epsilon model is chos e for turbulenc e model and pressure-velocity coupling respectively. The simulation was steady and moving reference frame is used to consider the impeller-volute interaction. The head and effici ency at diff erent flow rates are pred ict ed and they agree with those avail able in literature for similar pump. From the simulation results it is observed that the pre di cti on of centri fugal pump are good and may help to red uce the required experimental work for the study of centrifugal pump performance. ABSTRACT OBJECTIVES Performance Curves of Centrifugal Pump: Head was determined by the following equation by changing outlet velocity so outlet pressure was also changed. = − Where pout is the total pressure at pump outlet, pin is the total pressure at pump inlet, ρ is the density of liquid and g is the gravitational acceleration. Hydraulic efficiency is calculated as: = Where M is the impeller torque, ω is the angular velocity. Figure below shows the variation of head and efficiency with flow rate. Theoretically it is expec ted that the head goes on dec reasin g as the flo w rate inc reases for backward curved blades. Here also it can be seen from Figure below that, the head decreases with an increase in flow rate. Figure also shows the variation of hydraulic efficiency with flow rate. As can be seen from the figure, the point of maximum efficiency is 0.41 m3/s. The right figure show the output power vs discharge. CONCLUSIONS Although specific experimental results are not available for the pump considered for this study, the results agree well with most of the available results obtained by different authors for a similar pump. From the study it was observed that there is a low pressure area at the suction side of blade inlet at small flow rate, as the flow increases, the area gets close to t he middle of blade suction side. The static pressure also increases on diffusion section of the volute outlet markedly at small flow rate while the static pressure on the same place decreases at higher flow rate. Visualization along impeller and through diffuser: Pressure Distribution Veloc ity Distribution At different flow rate determination of: Head Efficiency Karachi Institute of Power Engineering By Shahid Masood Performance Prediction & Flow Simulation of Centrifugal Pump Using CFD-Tool GAMBIT MODELING A 2D centrifugal pump is modeled in gambit with the following pump specificatio ns and model is shown in Fig below. Inlet Dia = 52mm Outlet Dia =124 mm Impeller Eye = 20mm Blade Number = 6 Blade Shape = Circular arc Out let blade angel=220 Involute Profile Equation R = 67℮0.115(θ-0.1145 ) FlUENT ANALYSIS Standa rd k-epsil on mod el was used for turbu lence calculati ons. The pres sure velocity coupling methods recommended for steady-state calculations are SIMPLEC due to its high convergence rate. Second order upwind scheme was employed for discretization for equations of momentum, turbulent kinetic energy and turbulent dissipation rate. Ve locit y-outlet boundar y cond ition was impo sed on pump inlet position. It was specified to be normal to the boundary and it is defined with reference to the absolute frame. The turbulence intensity for all conditions is considered 1%. Pressure inlet was kept constant of 10000Pa. A constant angular velocity of 2900 rpm was imposed for rotating fluid. RESUTLS AND DISCUSSION Pressur e Distribution: The contour plot of variation of Static Pressure is shown in Fig below, It can be seen fro m the fig ure that, static pressure ins ide imp elle r and vol ute is asymmetry distributed. The maximum static pressure area appears at volute tongue and outlet regions and the minimum one at the back of blade at impeller inlet region. Velocity Distribution: The contour plot of absolute velocity distribution is shown in Fig below. As shown in the figure, the velocity increases from impeller inlet to outlet and reaches a peak value of 23.1 m/s at impeller outlet. After entering the volute, the velocity begins to fall down, reaching the lowest at the outlet region inside the volute. Generated by Foxit PDF Creator © Foxit Software http://www.foxitsoftware.com For evaluation only.
-
Upload
shahid-masood -
Category
Documents
-
view
3 -
download
0
description
Centrifugal pump
Transcript of PosterPresentations.com A1 Template V5
-
RESEARCH POSTER PRESENTATION DESIGN 2012
www.PosterPresentations.com
The complex internal flow of water of centrifugal pump through impeller anddiffuser can be predicted with the help of computational fluid dynamic, itfacilitating the product development process of pumps. In this thesis a CFD code isused to solve the governing equation of flow field. A 2-D simulation of turbulent fluidflow is presented to visualize the flow in centrifugal pump, including the pressureand velocity distributions. The standard k-epsilon model is chose for turbulencemodel and pressure-velocity coupling respectively. The simulation was steady andmoving reference frame is used to consider the impeller-volute interaction. The headand efficiency at different flow rates are predicted and they agree with thoseavailable in literature for similar pump. From the simulation results it is observedthat the prediction of centrifugal pump are good and may help to reduce therequired experimental work for the study of centrifugal pump performance.
ABSTRACT
OBJECTIVES
Performance Curves of Centrifugal Pump:
Head was determined by the following equation by changing outlet velocity so outlet pressure was also changed.
=
Where pout is the total pressure at pump outlet, pin is the total pressure at pumpinlet, is the density of liquid and g is the gravitational acceleration.
Hydraulic efficiency is calculated as:
=
Where M is the impeller torque, is the angular velocity.
Figure below shows the variation of head and efficiency with flow rate. Theoreticallyit is expected that the head goes on decreasing as the flow rate increases forbackward curved blades. Here also it can be seen from Figure below that, the headdecreases with an increase in flow rate. Figure also shows the variation of hydraulicefficiency with flow rate. As can be seen from the figure, the point of maximumefficiency is 0.41 m3/s. The right figure show the output power vs discharge.
CONCLUSIONS
Although specific experimental results are not available for the pump considered forthis study, the results agree well with most of the available results obtained bydifferent authors for a similar pump. From the study it was observed that there is alow pressure area at the suction side of blade inlet at small flow rate, as the flowincreases, the area gets close to the middle of blade suction side. The static pressurealso increases on diffusion section of the volute outlet markedly at small flow ratewhile the static pressure on the same place decreases at higher flow rate.
Visualization along impeller and through diffuser:
Pressure Distribution
Velocity Distribution
At different flow rate determination of:
Head
Efficiency
Karachi Institute of Power Engineering
By Shahid Masood
Performance Prediction & Flow Simulation of Centrifugal Pump Using CFD-Tool
GAMBIT MODELING
A 2D centrifugal pump is modeled in gambit with the following pump specifications and model is shown in Fig below.
Inlet Dia = 52mm
Outlet Dia =124 mm
Impeller Eye = 20mm
Blade Number = 6
Blade Shape = Circular arc
Out let blade angel=220
Involute Profile Equation
R = 670.115(-0.1145)
FlUENT ANALYSIS
Standard k-epsilon model was used for turbulence calculations. The pressurevelocity coupling methods recommended for steady-state calculations are SIMPLECdue to its high convergence rate. Second order upwind scheme was employed fordiscretization for equations of momentum, turbulent kinetic energy and turbulentdissipation rate.
Velocity-outlet boundary condition was imposed on pump inlet position. It wasspecified to be normal to the boundary and it is defined with reference to theabsolute frame. The turbulence intensity for all conditions is considered 1%. Pressureinlet was kept constant of 10000Pa. A constant angular velocity of 2900 rpm wasimposed for rotating fluid.
RESUTLS AND DISCUSSION
Pressure Distribution:
The contour plot of variation of Static Pressure is shown in Fig below, It can be seenfrom the figure that, static pressure inside impeller and volute is asymmetrydistributed. The maximum static pressure area appears at volute tongue and outletregions and the minimum one at the back of blade at impeller inlet region.
Velocity Distribution:
The contour plot of absolute velocity distribution is shown in Fig below. As shown inthe figure, the velocity increases from impeller inlet to outlet and reaches a peakvalue of 23.1 m/s at impeller outlet. After entering the volute, the velocity begins tofall down, reaching the lowest at the outlet region inside the volute.
Generated by Foxit PDF Creator Foxit Softwarehttp://www.foxitsoftware.com For evaluation only.
