Centrifugal pump design and analysis
Aim: - To create a centrifugal pump then run a parametric study in flow simulation and obtain the relationship between Pressure ratio and mass flow rate .
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. The fluid enters the pump impeller along or near to the rotating axis and is accelerated by the impeller, flowing radially outward into a diffuser or volute chamber (casing), from which it exits.
Model
- Create a sketch of impeller in the top plane and extrude it to 10mm
- Create and cassing around the impeller with inlet and outlet tubes
NOTE :- In solidworks for rotation we are using moving reference frame approach for this we create an additional zone around the impleller and give rotational velocity to that component
Flow simulation
- Go to solidworks simulation and add lids to both inlet and outlet
- Go to wizard add project name select unit systum to SI systum , analysis type to internal and select rotation and in next window select water as fluid with default conditions
- Go to component control in input data and unselect our reference frame of rotaion
- Go to rotating region and insert the refrence frame with the angular velocity of 2000 rad/s
- Insert boundary conditiion
- Environment Pressure at inlet as 101325Pa
- Velocity at outlet as 10m/s
- Add goals to calculate pressure and mass flow rate
- Insert flow trajecties of velocity and cut plots for velocity and pressure contour
- Run a new parametric study with inlet as outlet velocity and create design study of outlet velocity of 5,10,15,20,25 and 30m/s
Results
- Outlet velocity 10m/s
- Velocity contour
- Flow trajectory
- Outlet velocity 15m/s
- Velocity contour
- Flow trajectory
- Outlet velocity 20m/s
- Velocity contour
- Flow trajectory
- Outlet velocity 25m/s
- Velocity contour
- Flow trajectory
- Outlet velocity 30m/s
- Velocity contour
- Flow trajectory
- Pressure and mass flow rate
- Negative mass flow rate means that the mass is leaving from that surface
- Pressure ratio and exit mass flow rate
- Pressure ratio = Outlet pressure/Inlet pressure
- Pressure ratio vs Velocity
- Mass flow rate vs velocity
- Pressure ratio vs mass flow rate
Conclusion
- As we increase the velocity the mass flow rate also increase with linear proportional as the other parameter affecting mass flow rate like area of cross section and density of water is constant
- When we increase the velocity the pressure ratio first increase , reaches to a maximum value and then start decreasing
- When we increase the mass flow rate the pressure ratio first increase , reaches to a maximum value and then start decreasing , it is generally a parabolic curve but because our dimension of centrifugal pump is not accurate and with proper clearance so there is a deviation from original curve