Centrifugal pump design and analysis
AIM: To study the design and analysis of Centrifugal pume and to perform the parametric study to obtain the relationship between Pressure ratio and Mass flow rate
Theoritical Background:
Pump
A pump is a device that moves fluids (liquids or gases) by mechanical action, typically converted from electrical energy into Hydraulic energy. Pumps can be classified into three major groups according to the method they use to move the fluid: direct lift, displacement, and gravity pumps.
Pumps operate by some mechanism (typically reciprocating or rotary), and consume energy to perform mechanical work moving the fluid. Pumps operate via many energy sources, including manual operation, electricity, engines, or wind power, and come in many sizes, from microscopic for use in medical applications, to large industrial pumps.
Classification of pumps
Centrifugal Pump:
Centrifugal pumps are often chosen for their high flow rate capabilities, abrasive solution compatibility, mixing potential, as well as their relatively simple engineering. A centrifugal fan is commonly used to implement a vaccum cleaner. The reverse function of the centrifugal pump is a water turbine converting potential energy of water pressure into mechanical rotational energy.
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.
Solid Modelling
Computational Domain
Meshing:
Baseline simulation:
Boundary condition - inlet face - Environmental pressure = 101325 Pa ,
Outlet face - Outlet velocity = 10 m/s
Goals - Surface Goals - Average total pressure at Outlet lid and inlet lid
Surface Goals - Mass flow rate at Outlet lid
Velocity Contour Pressure Contour
Flow Trajectories
Velocity Pressure
Parametric Study
Case 1: Outlet velocity = 10m/s
Velocity Contour Pressure Contour
Flow Trajectories
Velocity Pressure
Case 2: Outlet velocity = 15m/s
Velocity Contour Pressure Contour
Flow Trajectories
Velocity Pressure
Case 3: Outlet velocity = 20m/s
Velocity Contour Pressure Contour
Flow Trajectories
Velocity Pressure
Case 4: Outlet velocity = 25m/s
Velocity Contour Pressure Contour
Flow Trajectories
Velocity Pressure
Case : Outlet velocity = 30m/s
Velocity Contour Pressure Contour
Flow Trajectories
Velocity Pressure
Output results of parametric study
Calculation of pressure ratio for different design points
Observations:
1] The pressure ratio is more in the regions of low velocity. The pressure ratio starts to decrease when the velocity increases.
2] The mass flow rate is expressed in negative trends because the fluid is going out of the domain
3] Mass flow rate is inversly proportional to Pressure ratio. We can clearly observe from the above graph that as the mass flow rate increases the pressure ratio drops