Centrifugal pump design and analysis

AIM:

To design and analyse a Centrifugal Pump.

OBJECTIVES:

1. To create a 3D model of a centrifugal Pump.
2. To obtain the relationship between Pressure ratio and mass flow rate (Performance diagram).

INTRODUCTION:

Centrifugal pumps are used to transport fluid by conversion of rotational kinetic energy to the hydrodynamic energy of the fluid flow. The rotational energy basically comes from the 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, from which it exits. 

GEOMETRY:

Boundary conditions

1. Inlet pressure : 101325KPa
2. Outlet velocity at exit: 10m/s

STEPS:

1. Model the system using solidworls sketch, boss extrude, sweep and revlolve tool.
2. Lids are created at the inlet port and outlet of pump to make the model water tight.
3. Activate the flow simulation plugin of solidwokrs in add-ins tab.
4. Select wizard and input respective details including medium as per parameters given above to set the project. Add rotation in the wizard settings.
5. Set the computational domain to 3D and set the domain in such a way that the silumation result is not affected.
6. Redefine the gloabal mesh for more accurate results.
7. Insert boundary conditions at inlet and outlet as given above.
8. Insert cutplot of top plane for velocity and pressure.
9. Set surface goals on the lid for Average input and output pressure, also mass flow rate at outlet.
10. A new parametic study is created. Input is given as outlet velocity wihich vary from 10 to 50 in a step of 10. Output are all the surface goals and cutplots. Set iteration = 500 and uncheck all options under calculation control option. Hit run. 

RESULTS:

A. Velocity cut plots at different velocities:

B. Pressure cut plots at different velocities:

C. Flow Trajectory:

PARAMETRIC STUDY:

A study has been carried out to understand the variation of mass flow rate and pressure ratio with respect to outlet velocity in a centrifugal pump. Here, the velocity has been varied from 10 m/sec to 30m/sec in 5 steps. Pressure ratio is the ratio of outlet pressure to the inlet pressure.

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 1 [Pa](outlet)	8562915.154	7547558.766	2984517.712	2758733.303	4537474.485
SG Mass Flow Rate 1 [kg/s]	-0.427180994	-0.692138324	-0.985329015	-1.23538344	-1.438651023
SG Av Total Pressure 2 [Pa](inlet)	1012310.386	924469.1175	339993.5671	378583.8262	865246.386
Pressure Ratio	8.458	8.164	8.778	7.286	5.244

Performance curve:

From the curve, it is clear that the mass flow rate increases with an increase in velocity.

From the curve, it is clear that the fluctuation in the pressure is due to the interaction of fluid (water) with impeller and casing.

Conclusion:

From the performance curve, it is clear that the mass flow rate increases with an increase in velocity and mass flow rate increases with an increase in velocity.