Centrifugal Pump Design and Flow Analysis

Introduction

Centrifugal pumps are the most common type of pump used in industry, agriculture, municipal (water and wastewater plants), power generation plants, petroleum and many other industries.

Centrifugal pumps are the primary pump type in the class of pumps called \"kinetic\" pumps and are distinctly different than \"positive displacement\" pumps. All centrifugal pumps include a shaft-driven impeller that rotates (usually at 1750 or 3500 RPM) inside a casing. Liquid flows into the suction port (inlet) of the casing and is thrown to the outside of the casing and then exits the discharge port. The velocity imparted to the liquid by the impeller is converted to pressure energy or \"head\".

Centrifugal pumps are unique because they can provide high or very high flowrates (much higher than most positive displacement pumps) and because their flowrate varies considerably with changes in the Total Dynamic Head (TDH) of the particular piping system. This allows the flowrate from centrifugal pumps to be \"throttled\" considerably with a simple valve placed into the discharge piping, without causing excessive pressure buildup in the piping or requiring a pressure relief valve. Therefore, centrifugal pumps can cover a very wide range of liquid pumping applications.

Centrifugal pump design dimensions in m

Diameter of the Volute casing is 0.04 m.
Thickness of the Volute casing is 0.01 mm.
Diameter Of the impeller is 0.02m

Boundary Conditions

Inlet suction pipe - environmental pressure [101325 Pa]
Outlet discharge - velocity [m/s].(10,15,20)
Mass flow rate at outlet.

Inlet and outlet total pressure

The rotational speed of this domain is 1000 rad/sec.

Cutplot for Velocity.

Flow Trajectories for Pressure.

Results

for 10m/s Outlet Velocity

Cutplot For Velocity

Flow Trajectory for Pressure

for 15m/s Outlet Velocity

Flow Trajectory for Pressure

for 20m/s Outlet Velocity

Flow Trajectory for Pressure

Observation

As Velocity increases we can observe that velocity is also increasing because mass flow rate is directly proportional to velocity that is

mass flow rate = density*area*velocity