Lab 1: SolidWorks Flow Simulation

Lab 1: SolidWorks

Flow Simulation

Jacob Fillinger

DMG 12:40

APP N06-1

2/26/2018

APP N06-1.1: Lab 01 Part 01 ENGR 1282.02H

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Lab 1.1: Simple Channel Assembly Coarse Mesh:

1. Insert screenshot of your goals plot below:

Figure 1: Plot of Max and Min Velocities through each iteration of the first simulation.

2. Insert screenshot of your pressure contour surface plot below:

Figure 2: Pressure Contour Surface.


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3. Insert screenshot of your Velocity Contours (z = 0.010 m) below:

Figure 3: Velocity Contour Cut Plot.

4. Insert a screenshot of your Velocity Vectors (z = 0.010 m) below:

Figure 4: Velocity Vectors at z = 0.010 m.


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5. Insert a screenshot of your Flow Trajectories below:

Figure 5: Flow Trajectories in the Channel.

Fine Mesh:

6. Insert a screenshot of your Goals Plot below:

Figure 6: Plot of Max and Min Velocities through each iteration of the fine mesh simulation.


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7. Insert screenshots of your 2-D velocity contour cut plots below (one screenshot at z = 0.010m; one screenshot showing all 3 contour plots near entrance with z offsets of -0.01230m, -0.01240m, -0.01250m):

Figure 7: Velocity Contour at z = 0.010 m.

Figure 8: Velocity Contour Cut Plots at z = -0.01230 m, -0.01240 m, and -0.01250 m.


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8. Insert a screenshot of your 3-D Velocity Contours below:

Figure 8: 3D Velocity Contours.

9. Insert a screenshot of your Sheer Stress Contours below:

Figure 9: Shear Stress at Bottom of Channel.


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10. Discuss the flow profiles you achieved in this part of the lab. Are the results similar to what you would expect based on your knowledge of fluid mechanics? Why or why not? Consider laminar vs. turbulent flow, the no-slip condition, as well as any other concepts you think are important.

The flow profiles matched expectations; as the flow passed the inlet channel, the velocity began to build throughout the entire cross-section, eventually reaching a constant velocity state once the flow had proceeded far enough. Also, the flow velocity was greatest at the center of the channel, and decreased to zero at the channel walls, obeying the no-slip condition. Also, the even cross-sections through the main part of the channel demonstrate laminar flow.

11. Discuss the differences you see between the results of the coarse and fine meshes. How do the flow velocities and profiles compare? Which mesh seems to do a better job of replicating the flow profile we would expect in the channel? (What known condition does one of the meshes violate, based on the flow profile produced?)

The fine mesh flow system has a much more even distribution of velocities in its velocity cross section, and its center has a much larger area of higher-velocity flow than the coarse mesh system. The fine mesh also creates rounder, more evenly dispersed velocity profiles in an ellipse shape, whereas the coarse mesh has an uneven velocity channel distribution almost shaped like a lemon. Furthermore, the coarse mesh’s velocity does not decrease to zero everywhere along the border of the channel, violating the no-slip condition. The fine mesh, on the other hand, perfectly obeys this condition. Thus said, the fine mesh does a much better job of creating the expected flow profile for this system.

12. Based on the results from this part of the lab, how important is establishing a quality mesh before running your flow simulation? What could happen if the mesh is too course? What drawbacks might be present when using a fine mesh compared to a course mesh?

A functional mesh is the only way to determine what a real-life velocity profile would resemble; having too course of a mesh would result in an inaccurate flow profile that may not even obey all the laws of fluid mechanics. The main problem with making a mesh too fine is that it could cause the computer to take a very long time to generate all the data of the flow profile.

13. After completing this part of the lab, how do you plan to assign a proper mesh for your custom chip design?

It will be important to ensure that every dimension of the channel is divided up into a representative number of cells in each direction (x,y,z). A fair amount of cells for a channel of about the same size they used would be about one cell for every 10 to 20 micrometers of each dimension.


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Lab 1.2: Complex Channel Assembly

1. Insert screen shot of your mesh below:

Figure 1: Channel Mesh of complex channel.

2. Insert screen shot of your goals plot below:

Figure 2: Goal plot of complex channel flow.


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3. Complete the table below with the results from your flow simulation:

Table 1: Flow Simulation Results.

Parameter Value

Max Velocity 0.0871224 m/s

Delta (over last 5 iterations) 3.46e-005 m/s

Average Velocity 0.0721616 m/s

Max Shear Stress 3.84 Pa

4. Insert screen shot of your Velocity Simulation (flow trajectories) below:

Figure 3: Flow Trajectories.


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5. Insert a screen shot of your Velocity Contours (lateral) below:

Figure 4: Lateral Velocity Contours.

6. Insert a screen shot of your Velocity Contours (transverse) below:

Figure 5: Transverse Velocity Contours.


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7. Insert a screen shot of your Pressure Contour below:

Figure 6: Pressure Contour.


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8. Insert a screen shot of your Sheer Stress Contours below:

Figure 7: Sheer Stress Contours.

9. Use your fluid mechanics program to simulate the flow simulation performed in this part of the lab. The dimensions of the complex channel you used for this part of the lab are below:

Length 22.30 mm Width 0.33 mm Height 0.13 mm

Below are the flow parameters:

Pressure Head (ΔP) Dynamic Viscosity (µ)

Density (ρ)

1000 Pa 0.0010014 Pa·s 998.16 kg/m3

Fill out the table below with the results of the SolidWorks flow simulation (from question 3) and the results from the fluid mechanics program:

Table 2: Results from SolidWorks simulation versus fluid mechanics program.

Parameter SolidWorks Fluid Mechanics Program

Average Velocity 0.0722 m/s 0.0631 m/s

Max Shear Stress 3.84 Pa 2.915 Pa

How do the two results compare? What discrepancies, if any, are present? Use your knowledge of the assumptions of both simulations to think of potential causes of any differences.


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The results are fairly similar, but the SolidWorks simulation produces higher values for each flow parameter. This can be accredited to the mesh used in the SolidWorks program; it may not have been fine enough, resulting in increased values. The fluid mechanics program had smaller values, caused by the assumption that the system was a completely perfect rectangular channel with no inlets or outlets.

10. Briefly discuss what each of the following plots shows you in regards to the flow in the channel simulation. Your discussion of each plot should indicate your understanding of the basic fluid mechanics principles we’ve learned in class. Be sure to address why the contours can change near the walls of the channel, where applicable.

Lateral velocity contours: The velocity contours were greatest at the middle height of the channel. As the height approached the top and bottom wall of the channel, the flow rate decreased at the same rate. This is due to the momentum transfer of shear stress. At the top and bottom walls of the channel, the flow rate approached zero. This information agrees with the no-slip condition, where the attraction between fluid and solid is greater than the attraction within the fluid. Also, once the flow was established, the height of the channel did not affect the flow rate, a principal of laminar flow. Transverse velocity contours: The velocity contours were the greatest at the center of the cross-section, and as the velocity contours move towards the wall vertically and/or horizontally, their value decreases. Eventually, the value reaches zero at the wall of the channel, obeying the no-slip condition. This is a two-dimensional representation of the momentum transfer of shear stress. Additionally, the velocity contours do not change corresponding to the length of the channel once the flow has been established, representing laminar flow. Pressure contour: Pressure is higher at the inlet than the outlet, creating a pressure differential. This is a result of the fluid not being able to flow through the channel all at once. It creates stacked layers of water that push down and towards the channel, increasing the force on the small opening area on the channel. Ultimately, this feature drives the flow of the channel. As the fluid flows through the channel, it receives less direct force from the inlet and steadily decreases in pressure until it reaches the outlet.

11. Shear stress contour: What effect, if any, do the inlet and outlet areas have on the flow? What does this tell you about the importance of entrance length? How will this affect your chip design and/or experimental procedure? Reference any corresponding figures which support your claim.

Shear stress is the greatest at the center of the channel. This force is what causes the fluid in the middle of the channel to move fastest and explains why flow velocities decrease as they approach the channel walls. As such, shear stress decreases towards the channel walls. The inlet and outlet areas cause quite a bit of irregularity in the distribution of shear stress, which indicates that the inlet and outlet both greatly affect flow. This can be seen in Table 2, where the inlet and outlet areas of the SolidWorks simulation are compared to the perfect rectangular channel of the fluid mechanics program. The SolidWorks model displayed a greater velocity and shear stress, both due to its extended inlet area. This demonstrates that entrance length causes a greater velocity, since there is less shear stress building up to the channel. This must be kept in mind when designing a real-world chip, as shear stress and fluid velocity will be different than expected if the inlet and outlet areas are prominent.

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Lab 1: SolidWorks Flow Simulation