Centrifugal pump design and analysis
1. INTRODUCTION
CENTRIFUGAL PUMP
Centrifugal pumps are used to transport fluids by the conversion of rotational kinetic energy to the hydrodynamic energy of the fluid flow. The rotational energy typically comes from an engine or electric motor.
2. AIM
To create a 3D-model of a centrifugal pump and to perform the flow simulation to determine the performance.
3. OBJECTIVE:
- To obtain the relationship between the pressure ratio and the mass flow rate.
- Pressure ratio= pressure at outlet/ pressure at inlet. &
- To obtain plots and results.
4. PROCEDURE:
- A centrifugal pump design starts with the design of blades, in our case, we haven’t taken the standard values i.e., we assumed dimensions of our own.
- The blade end to the center was taken as 0.008m
- Then the outer casing was designed and its diameter was taken as 0.09m
- The inlet cylinder was designed by selecting the top plane and it has 0.03m diameter.
- The outlet cylinder profile was then drawn by creating the plane normal to the blade profile and the cylinder has 0.009 m diameter and 0.10 m length.
- All the profiles are then combined in-order so that it will be a single part.
- The cylinder inlet and outlet was then made as a shell with thickness 0.001m.
- Then the wizard option was chosen to perform the flow simulation and the lids are made to the cylinder.
- The flow simulation was then performed by giving the boundary condition and goals.
FLOW SIMULATION-INPUT VALUES:
- Simulation type: internal flow
- Features: rotation with local region value
- Fluid: water (flow type- laminar and turbulent).
- Boundary conditions:
- Inlet cylinder -lid 1-Environmental pressure – 1 atm
- Outlet cylinder-lid 2-Outlet velocity-10 m/s
- Surface goals:
- Lid 2-total average pressure and mass flow rate.
- Lid 1-mass flow rate.
- Mesh level- 3
- Iteration-500
The parametric study has been created once the baseline simulation is done and then the velocity values from 10-30 m/s for 5 intervals are taken in order to obtain the velocity cut plot and flow trajectories.
5. RESULTS
- At 10m/s velocity
Velocity Cut Plot
Pressure Cut Plot
Flow Trajectory Plot
- At 15m/s velocity
Velocity Cut Plot
Pressure Cut Plot
Flow Trajectory Plot
- At 20m/s velocity
Velocity Cut Plot
Pressure Cut Plot
Flow Trajectory Plot
- At 25m/s velocity
Velocity Cut Plot
Pressure Cut Plot
Flow Trajectory Plot
- At 30m/s velocity
Velocity Cut Plot
Pressure Cut Plot
Flow Trajectory Plot
CALCULATED TABLE
| Goal (Value) | Design Point 1 | Design Point 2 | Design Point 3 | Design Point 4 | Design Point 5 |
| Velocity normal to face (Outlet Velocity 1) [m/s] | 10 | 15 | 20 | 25 | 30 |
| SG Av Total Pressure [Pa] | 2234871.291 | 4731630.711 | 8688940.134 | 1967627.076 | 2377894.681 |
| Inlet pressure | 101325 | 101325 | 101325 | 101325 | 101325 |
| SG Mass Flow Rate [kg/s] | -0.495550946 | -0.741318659 | -0.981927674 | -1.238302699 | -1.48426257 |
| Pressure Ratio | 22.05646476 | 46.69756439 | 85.75317181 | 19.41896941 | 23.46799587 |
PLOTS
6. CONCLUSION
From the above simulation, the mass flow rate vs pressure ratio plot was obtained and it is found that as the velocity increases the pressure ratio varies with respect to the increase in flow rate. The variation in the pressure ratio is nonlinear as the boundary condition given to the simulation study was an assumed condition, in general, the pressure ratio decreases with an increase in velocity at the outlet. To get a better performance curve it is advised to take the boundary conditions of a standard pump.