Centrifugal pump design and analysis

Aim: Design and flow simulation of centrifugal pump and Obtain the relationship between Pressure ratio and mass flow rate and explain your results.

Abput :

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. They are a sub-class of dynamic axisymmetric work-absorbing turbomachinery.[1] 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.

Common uses include water, sewage, agriculture, petroleum and petrochemical pumping. Centrifugal pumps are often chosen for their high flow rate capabilities, abrasive solution compatibility, mixing potential, as well as their relatively simple engineering.[2] A centrifugal fan is commonly used to implement a vacuum cleaner. The reverse function of the centrifugal pump is a water turbine converting potential energy of water pressure into mechanical rotational energy.

Modeling :

• Diameter of delivery pipe = 10mm
• Diameter of suction pipe = 15mm
• Diameter of outer and inner side of impeller = 80mm, 20mm
• Diameter of revoving part = 80.4mm
• Diameter of casing = 90mm

using this data 2D sketch are created and converted into 3d model by extruding and sweep command respectively

Flow simulation :

• create the lids on open ends
• set the analysis type as internal flow and set the rotation as local region average
• use water as fluid
• put the boundary conditions as environmental pressure as 101325 Pa and output velocity as 10m/s
• put the goals as average total pressure and surface mass flow rate
• increase the level of the initial mesh
• set the results for goals
• create the parametric study with input as velocity and output as goals
• run the simulation

results :

we know pressure ratio = Outlet total pressure/ Inlet total pressure, inlet pressure = 101325 Pa

therefore the relation between pressure ratio and mass flow rate is as follow

Conclusion :

From the results, we can say that for this centrifugal pump mass flow rate and average pressure decreases and from the results of pressure vs mass flow rate as the mass flow rate decreases the value of pressure ratio is decreases