Centrifugal pump design and analysis

AIM : To create a 3D model for a centrifugal pump and to run a flow simulation.

THEORY : Centrifugal pumps are a sub-class of dynamic axisymmetric work-absorbing turbomachinery 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.

PROCEDURE :

•Create a centrifugal pump of outer volute diameter = 0.06m

•Inner volute diameter = 0.03m

•Arc angle of 136 degrees for the blades

•Number of blades = 5

•Diameter of inlet pipe = 0.025m

•Length of inlet pipe = 0.14 m

•Diameter of outlet pipe = 0.015 m

•And the set up a rotational domain

•Let the boundary conditions at inlet have environmental pressure and at the initial outlet velocity = 10m/s

•Create a new parametric study with outlet velocity of 10 , 30 & 50 m/s

•Create cut plots and goal plots for the required parameter.

•Run the simulation .

GRAPH PLOTS :

Velocity plot at 10 m/s :

Velocity plot at 30 m/s :

Velocity plot at 50 m/s :

PRESSURE RATIO & MASS FLOW RATE RELATIONSHIP :

Pressure ratio = Outlet total pressure/ Inlet total pressure

pressure ratio at point 1 = 0.09405

pressure ratio at point 2 = - 0.13199

pressure ratio at point 3 = - 0.03148

Total pressure at inlet :

Total pressure at outlet :

Mass flow rate :

Pressure ratio v/s mass flow rate :

OBSERVATION & RESULTS : From this we observe that -

1) The mass flow rate increases as the pressure ratio decreases

2) As outlet velocity increases there will be a decrease in the average pressure.

Velocity Flow trajectory :