Centrifugal pump design and analysis

Aim : In this Project, creating a 3D model of a Centrifugal pump,run a baseline flow simulation where inlet flow takes place and then perform a parametric study for different velocities and Obtain the relationship between Pressure ratio and mass flow rate.

Introduction :

Centrifugal Pump : When the impeller is made to rotate, it makes the fluid surrounding it also rotates. This imparts centrifugal force to the water particles, and water moves radially out. Centrifugal pumps are used to induce flow or raise pressure of a liquid.

pressure ratio = Outlet total pressure/ Inlet total pressure

procedure :

create a three model of centrifugal pump.

Apply flow simulation and create computational domain.

The Rotating Region is selected and the speed is set to 1000 rpm.

The Inlet Boundary Condition is set as Environmental Pressure of 1 bar.

The Outlet Boundary Condition is the Exit Velocity of 15 m/s.

The Surface Goal is set in the Inlet and the Outlet faces.

Then the Mesh is created for the model and the Automatic mesh level is set into 3 and Advanced Chanel refinement is selected.

Run the Simulation the cut plots are created for the Pressure and Velocity and get the values for the goals.

Pressure Trajectory:

Results of parametric study:

For this test, I have set the input variables as output velocity and the values are 10 m/s, 15 m/s, 20 m/s, 25 m/s, 30 m/s.

velocity	SG Av Total Pressure inlet [Pa]	SG Av Total Pressure outlet [Pa]	Pressure Ratio	mass flow rate
10	956771.2649	1017859.99	1.063848829	-0.8510142
15	3443065.989	2208783.22	0.641516377	-1.2723541
20	1011845.145	1110356.45	1.097358084	-1.703307159
25	1624892.833	1425987.25	0.877588491	-2.129270329
30	2304289.185	1578422.15	0.684993082	-2.555883192

Outputs :

pressure Plot at 10m/s

pressure Plot at 15m/s

pressure Plot at 20m/s

pressure Plot at 25m/s

pressure Plot at 30m/s

Velocity vs pressure ratio :

Velocity vs mass flow rate:

Observation and Conclusion

1. From the First plot we can see that initially, the velocity is less so the mass flow rate is less when the velocity increases the mass flow rate increases.
2. Velocity plots have proper indication of outflow velocity as assigned. Show in the plots above.
3. A pump does not create pressure it only creates flow. Pressure is a measurement of the resistance to flow
4. It is evident from other similar studies pressure ratio decrease as the velocity at outlet increase but in my case, the pressure ratio varied due to technical failure of my laptop which did not perform accurately as expected.