Flow through a pipe using Solidworks Flow Simulation
Aim :
Run a pipe flow simulation with an inlet Reynolds number of 100,1000 and 10,000.
For each of these cases do the following
1. Place line probes at 95%, 90% and 85% of the pipe length.
2. Compare the normalized velocity profile at each of these locations
3. Normalize the velocity profile by the inlet velocity.
Theory:
When a fluid flows through a pipe the fluid near the walls of the pipe becomes stationary due to no-slip condition and as we move away and away from the wall the velocity becomes more and more. For laminar flow, the velocity in the middle becomes twice the average velocity.
The layers of the fluid above try to slow down because of the shear stress because of the viscosity of the fluid
When a uniform flow enters inside the pipe, the boundary layer begins to form. The boundary layer is the region where there are considerable effects of viscosity.
Boundary layer thickness is the distance from the wall where the velocity becomes 99 percent of the inlet velocity.
As we move away from the starting point boundary layer thickness begins to grow.
It has been demonstrated in the project that how the velocity contour looks at different cross-sections
and how the velocity profile looks for different Reynolds number at different locations using a line probe.
Model a pipe of diameter 0.052m and extrude it to 1 m. Now create a shell of thickness 0.0015 m. Now sketch 3 lines at a distance of 0.85,0.90 and 0.95 m from the origin.
Create lids to close the geometry and thus create a confined body.
Procedure:
1. Add boundary condition for the inlet flow, outlet flow and the wall of the pipe
2. Set up the mesh as required
3. Open a new parametric study
4. Add input parameter as flow velocity as we need to calculate the velocity profiles for three different Reynold's number
5. In the output, parameters add cut plots and XY plots
6. Now in the scenarios copy-paste the study and change the velocity for different Reynolds number
7. Run the simulation
Case 1: At Reynold's number = 100;
1. At 85% of the length of the pipe.
2. At 90% of the length of the pipe.
3. At 95% of the length of the pipe.
4. The combined velocity plot at all the 3 line probes is:
Case 2: At Reynold's number = 1000;
1. At 85% of the length of the pipe.
2. At 90% of the length of the pipe.
3. At 95% of the length of the pipe.
4. The combined velocity plot at all the 3 line probes is:
Case 3: At Reynold's number = 10000;
1. At 85% of the length of the pipe.
2. At 90% of the length of the pipe.
3. At 95% of the length of the pipe.
4. The combined velocity plot at all the 3 line probes is:
The simulation animation for all the three cases is shown below:
Case 1: At Reynold's number = 100;
Case 2: At Reynold's number = 1000;
Case 3: At Reynold's number = 10000;
Results :
1. The velocity near the wall is zero and increases as we move towards the center due to shear stress between the layers of fluid.
2. As we increase the velocity, the velocity profile becomes more flatter this is because when the flow becomes turbulent mixing takes place more and hence the effect of viscosity is less.
3. The velocity profile at 85,90 and 95 percent of the length is nearly the same. This is because the entrance length for the pipe is very small and thereafter the velocity profile does not change much.