Centrifugal pump design and analysis

1. AIM : To create a model and run a flow simulation of centrifugal pump using SolidWorks CFD.

2. OBJECTIVE :

• Create 3D model of centrifugal pump
• Initialize the simulation with providing lids
• Assign boundary conditions and goals to the design
• Run the simulation for 500 iterations with basic mesh with advance refinement
• Obtain the results and compare it.

3. THEORY :

A centrifugal pump is a mechanical device designed to move a fluid by means of the transfer of rotational energy from one or more driven rotors, called impellers. Fluid enters the rapidly rotating impeller along its axis and is cast out by centrifugal force along its circumference through the impeller’s vane tips. The action of the impeller increases the fluid’s velocity and pressure and also directs it towards the pump outlet. The pump casing is specially designed to constrict the fluid from the pump inlet, direct it into the impeller and then slow and control the fluid before discharge.

fig.1: CENTRIFUGAL-VOLUTE-CASING-DESIGN

Centrifugal pumps are used to induce flow or raise a liquid from a low level to a high level. These pumps work on a very simple mechanism. A centrifugal pump converts rotational energy, often from a motor, to energy in a moving fluid. The two main parts that are responsible for the conversion of energy are the impeller and the casing. The impeller is the rotating part of the pump and the casing is the airtight passage which surrounds the impeller. In a centrifugal pump, fluid enters into the casing, falls on the impeller blades at the eye of the impeller, and is whirled tangentially and radially outward until it leaves the impeller into the diffuser part of the casing. While passing through the impeller, the fluid is gaining both velocity and pressure.

4. PROCEDURE :

Design a 3D model of centrifugal pump with specific dimensions.

Start the simulation with providing lids on both the openings for proper simulation.

Select the above mentioned parameters for Simulation.

Insert boundary conditions for inlet as Environmental pressure of 1 bar and outlet as Exit Velocity of 10 m/s.

Surface goals are set at inlet and outlet faces.

Mesh is created for model at level 3 and advance channel refinement is selected.

Run the simulation for 500 iterations for cut plots of Velocity and pressure and flow trajectories

5. BODY OF CONTENT :

Firstly, we will create a 3D model of the centrifugal pump with lids at openings,

fig.2 : 3D model of centrifugal pump

• The impeller is designed with five blades and a casing is provided to it with an inlet and out flow pipe.

To start the flow simulation, we will provide some initial conditions like Unit System, Fluid type, Analysis type, Thermodynamic parameters etc.

Parameters for Simulation :

Type of Simulation = Static Simulation

Analysis type = Internal flow

Fluid used = Water

Type of Flow = Laminar and turbulent

Rotation type = Local Region Averaging

Inlet Boundary Conditions = Pressure of 1 bar

Outlet boundary Conditions = Velocity of 10m/s

Setting up parameters for our flow simulation :

Assigning Computational Domain,

now, selecting rotating region,

Then going to select the boundary conditions for inlet and outlet flow as,

Parametric study :

Set the input variables as the outlet Velocity with discrete values of 10m/s, 15m/s, 20m/s, 25m/s, 30m/s.

Cut plots of Velocity and pressure can be created.

6. RESULTS :

Velocity cut plot :

Pressure cut plot :

Flow Trajectory :

fig.4: SG Average Total Pressure at different velocities

Animation Video :