Centrifugal pump design and analysis

AIM: Performance diagram. Obtain the relationship between Pressure ratio and mass flow rate and explain your results.

Pressure ratio = Outlet total pressure/ Inlet total pressure

INTRODUCTIONS : Centrifugal pnmps are used to transport fluids by the conversion of notational 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. The fluid enters the pump impeller along or the near the rotating axis and is accelerated by the impeller, flowing radially outward into a diffuser or volute chamber, from which is exist.

COmmon use include water, sewage, agriculture, petroleum and petrochemical pumping. Centrifugal pumps are often chosen for their high flow rate compabilities, abrasive solution compability, mixing potential, as well as their relatively simple engineering. A centrifugal fan is cimmonly used to implement a vacume cleaner. The reverse function of centrifugal pump is a water turbine converting potential energy of water pressure into mechanical rotational energy.

At low mass flow rate operation, the pressure ratio over the impeller is high. The high back pressure, downstream of the impeller, pushes flow back over the tips of the rotater blades towards the impeller eye.

GOVERNING EQUATION: Pressure ratio = Outlet total pressure/ Inlet total pressure

PROCEDURE:

• Firstly we creat a cad model of centrifugal pump with proper dimensions, extrude, merge result, shell, avoid the merging of the existing geometry.
• Create a zone for rotation of liquid and apply transparency on whole geometry.
• To create a mesh in solid works , moving frame reference is employed and a control volume is constructed to provide the rotation for simulation.
• Applying some boundary condition for inlet and outlet flow.
• A flow simulationis ideated with specified boundary conditionand goals to be obtained.
• The iteration are fixed with a value of 500 to avoid early convergence resulting in unsatisfactory resulting.
• A parameter studyis set up with the variable being the outlet velocity. The simulationis run for 5 design points and the result are obtained for verification.

RESULTS:

Velocity cut plot (10 m/s outlet velocity)

It's rotating in clockwise 🔃 direction and shucking the water and water 💦 in high velocity in backside of blades.

Pressure cut plot (10 m/s outlet velocity)

Here we can see it's generate high pressure with wall.

Velocity flow trajectory (10 m/s outlet velocity)

Pressure flow trajectory (10 m/s outlet velocity)

Inlet total pressure (5 points)

Outlet tptal pressure (5 points)

Mass flow rate(outlet)

Goal (value)	Design point 1	Design point 2	Design point 3	Design point 4	Design point 5
Vel normal to face(Out.Ve. 1)[m/s]	10	15	20	25	30
SG Av total pressure 1[Pa]	2133839.19	2002752.25	3571378.04	4478113.65	1752112.78
SG Av total pressure 2[Pa]	274111.25	249612.78	501887.93	5557330.61	237868.95
SG mass flow rate 1[kg/s]	-0.24550521	-0.3693623	-0.48660369	-0.5871866	-0.740338

CONCLUSION : The simulation carried out gives a clear perception of the working of centrifugal pump. It can also be concluded that the impact of the mass flow rate is highly significant in determining the outlet total pressure, i.e. our required parameter dependency on the variables.