Pump flow analysis
Problem statement
For this project, you will have to show the following
For this challenge, you will create the 3D model for a centrifugal pump and then run flow simulation
- Performance diagram. Obtain the relationship between Pressure ratio and mass flow rate and explain your results.
- Pressure ratio = Outlet total pressure/ Inlet total pressure
Solution
3d model of the pump and internal parts
Rotating reference frame with the internal impeller
impeller with five blades
pressure diagram showing the different pressures across different regions of the casing cross-section
from the image above it can clearly be seen that the maximum pressure region is at outlet (shown in orange colour). the core region of the pump shows the area with minimum pressure ( shown in blue colour).around the periphery the pressure varies from a maximum to minimum range.
Velocity trajectories showing the velocity and motion of the fluid flow in a centrigugal pump.
From the image it can clearly be concluded that the flow does not have a maximum velocity region ( in comparision to the range shown in the legend) except at the top part where fluid deviates from its straight path. Everywhere else the velocity has an increasing nature , when compared in from centre to its perihery.
For this parametric study - outlet velocity is taken as a varying parameter.
outlet velocity is varied in steps of 10 at the outlet of the pump and the total inlet pressure is kept at atmospherric pressure.
| Design Point 1 | Design Point 2 | Design Point 3 | Design Point 4 | Design Point 5 | Design Point 6 | |
| Velocity at outlet normal to face (Outlet Velocity 1) [m/s] | 10 | 20 | 30 | 40 | 50 | 60 |
| outlet Total Pressure 1 [Pa] | 6927265.645 | 5697627.019 | 5635117.727 | 4727722.043 | 3598820.378 | 2614088.754 |
At different velocities of flow at outlet the total pressure changes. with a step increase in the outlet velcity the total pressure at outlet decrases ( as shown in tha table above.)
Comparision between the Pressure ratio and the mass flow rate.
| pressure ratio | mass flow rate |
| 68.36679639 | 8.907346373 |
| 56.2312067 | 17.83321198 |
| 55.61428795 | 26.75306251 |
| 46.65898883 | 35.67253351 |
| 35.51759564 | 44.58973804 |
| 25.79905012 | 53.50537791 |
From the table above it can clearly be concluded that as the pressure ratio decreases , mass flow rate increses linearly.Plot of the above two values has been plotted on a line graph as shown below.
Chart 1 - line graph 1
y co-ordinate shows the number line showing the pressure ratio/mass flow rate and the x co-ordinate shows the number of iterations/scenarios considered in this study.
A direct comparision of different pressure ratios and mass flow rate clearly shows that the mass flow rate increases linearly in all the six scenarios, while the pressure ratio decreses in non-uniform manner.
it also clearly suggests that as the pressure at the outlet decreases , it allows the velocity to increase and inturn allows maximum amount of fluid to escape the system.
the above image shows the increamental value of the mass flow rate for the values of pressure ratio taken in six different scenarios.
Below is the link to the excel file of the parametric study taken in this study.
https://drive.google.com/open?id=19i0OVKQB_5uSf7sjWBaou4QSR7juvwCr