Centrifugal pump design and analysis

Aim :
To Run parameteric study on Centrifugal pump to understand Pressure ratio vs Mass flow characteristics

Introduction:
Centrifugal pump is used to convert rotational kinetic energy into hydrodynamic energy. By creating vaccum due to rotation of impeller fluid is sucked from lower region ( reservoir ) and pressurizes to upper region ( tank ).

Parts of Pump:
1. Casing
2. Impeller
3. Drive Shaft
4. Inlet Pipe
5. Outlet Pipe

Theory:

Centrifugal Pump is governed by
1. Continuity equation
(Area X Velocity ) @ Inlet = (Area X Velocity ) @ Outlet
2. Bernoulli equation
( Pressure head + kinetic head + gravity head ) @ Inlet = ( Pressure head + kinetic head + gravity head ) @ Outlet + Head loss due to friction

Modelling:

3D model of centrifugal pump with above parts were designed.

Impeller diameter: 120 mm
Casing diameter : 300mm

Simulation Setup:

Moving Reference Frame method is used here to simulate the pump flow. It works with Closed geoemetry, hency additional Dummy rod is placed over impeller.

Flow type: Internal
Fluid : Water
Rotation type : Local region ( Averaging )

Parametric study:

Boundary Condition :
Inlet : Total Pressure = 101325 Pa
Outlet: Velocity range : 10 ,15, 20, 25, 30 m/s
Mesh Size : 3
Surface Goals : Pressure Ratio = Outlet Total Pressure / Inlet total Pressure

Mass flow Rate @ Outlet
Total pressure @ Outlet

No.Of Iterations: 500

Result:

Flow Trajectory: Velocity Profile

Flow simulation video link

https://youtu.be/IjUZlVYQ444

Conclusion:

As Pressure Ratio decreases mass flow rate also decreases , when velocity increases.