Pipe Flow Simulation
AIM:
To run a pipe flow simulation with an inlet Reynolds number of 100,1000 and 10,000.
THEORY:
Fluid Flows can be classified into various types. They are:
(i) Steady and Unsteady Flow.
(ii) Uniform and Non-Uniform Flow
(iii) Incompressible and compressible flow
(iv) Laminar and Turbulent Flow
Laminar Flow: Also known as viscous flow or stream-line flow. It has low fluid velocity.
Turbulent Flow: High velocity flow. Whirl formation or 'eddies' takes place. Fluid particles move in a zig-zag manner.
To determine whether flow is laminar or turbulent we use a constant term known as Reynolds number.
Reynolds Number (Re) = (rho*V*D)/(mu)
where rho= Density of the fluid
V= velocity of flow
D= Diameter of pipe/tubing through which fluid is flowing
mu= Dynamic Viscocity of the fluid.
For pipe flows,
If Re < 2000 -----> Flow is laminar
If Re > 4000 ------> Flow is turbulent
PROCEDURE:
We have to run pipe flow simulation for Reynolds number 100,1000 and 10000.
rho, D and mu will be constant in all three cases. Hence we can substitute and find V.
Taking Fluid to be water,
rho= 1000 kg/m^3
D= 0.04m or 40mm
mu= 0.000992 Pa-s (source: https://www.engineeringtoolbox.com/water-dynamic-kinematic-viscosity-d_596.html)
Case 1: Re= 100
100 = (1000*V1*0.04)/0.000992
Therefore V1= 0.002498 m/s
Case 2: Re= 1000
1000 = (1000*V2*0.04)/0.000992
Therefore V2= 0.02498 m/s
Case 3: Re= 10000
10000 = (1000*V3*0.04)/0.000992
Therefore V3= 0.2498 m/s
Now open SolidWorks.
Create a new document. In type, select Part design. In the top plane, draw a circle of radius 0.02m. Exit sketch and extrude it by length 0.2m. Then shell the cylinder using the Shell command, keeping thickness as 0.001m. Then go to the front plane. Draw a horizontal line at 95%,90% and 85% of the full length of the cylinder.(0.19,0.18,0.17). These will be the probes
Then click on the flow simulation tab and select the create lids option. Select the two circular faces as the lids and click OK. Save the document.
Go to New. Type the name of the document. Right click Input Data and select General Settings. A dialogue box opens. Select the necessary requirements of the simulation like fluid to be used(water), flow type(laminar), internal flow,etc. Click on Finish when done.
The computational domain appears. Next go to Mesh --> Global Mesh ---> Edit Basic Definition
Change mode to manual from automatic.
Nx= 20
Ny= 20
Nz= 60
Confirm.
Next go to Results--->XY Plots--->Insert New Plots. Here, we are creating plots for showing velocity profile at 95%,90% and 85% of full length. So we create three plots Velocity 0.95, 0.9 and 0.85. Then Go to Mesh---> Hide basic mesh.
Then we Run the simulation.
After running the simulation, we make three cut-plots (0.95,09 and 0.85 of full length). Property is Velocity and number of levels is 10. Click OK.
Then we go near the project name and right click and select "New Parametric Study".
Under Input Paramerters, Click on Add Simulation parameters. Add Number of cells per X,Yand Z(Come under Basic Mesh). Then go to Boundary Conditions--->Inlet Velocity---> Velocity normal to face. Under Velocity normal to face, select Values and add 0.02498 and 0.2498 (Re 1000 and 10000). Then We go to output parameters.
Under Output Parameters, Select Add Results. We then add the three Cut Plots that we have created and also the three plots. Then we Click Scenario.
Finally, we click Run.
The results are obtained.
RESULTS:
(i)Probe 0.95
Velocity = 0.002498 m/s
Velcity 0.02498 m/s
Velocity= 0.2498 m/s
(ii)Probe 0.90
Velocity= 0.002498 m/s
Velocity= 0.02498 m/s
Velocity= 0.2498 m/s
(iii)Probe 0.85
Velocity= 0.002498 m/s
Velocity= 0.02498 m/s
Velocity= 0.2498 m/s