The University of Nevada, Reno lacks a water trough in the Mechanical Engineering department for students and faculty to use. The task for Water Works is to create a water tunnel that is fully functional and can be utilized for testing and experiments. The water tunnel design is comparable to models that are sold in the market today while costing significantly less. The biggest task in hand for the team is to create a controller that changes the flow rate of water, in laminar ranges, while maintaining the height of the water level across the test viewing section. This webpage is focused on the design process and development of a water tunnel for the University of Nevada, Reno.
Phase I: Design Inputs
The purpose of Phase I was to compile a comprehensive set of established goals for the project design and development.
- Target product cost: $3500
- Portable and easy to move (less than 300 kg to transport when empty)
- Test size must accommodate 200x300x200mm specimen
- Laminar flow is the dominant type of flow.
- Controllable water velocity ranging from 0-0.1 m/s
- Water shall be able to be drained
- Transparent viewing area required
- Viewing area shall be at least 600 cm^2
- Instruction Manual for operation required
- Corrosion resistant materials in areas where water touches (Acrylic)
- Controller must be able to maintain a constant steady flow rate
- Must be able to indicate flow speed in test area to user
- Appropriate hazard labels required
- Product life expectancy of at least 10 years
- Product shall not be able to tip under 10 degrees.
This project was first formed by team sponsor and mentor Dr. Matteo Aureli, a research professor in the Mechanical Engineering Department at the University of Nevada, Reno. Team Water works designed a water tunnel that is mounted on a steel frame with four wheels to give mobility, a Plexiglas viewing section, PVC pipe to channel the flow, a pump a variable speed flow controller to adjust the speed of the water, and composite material inlet and outlet reservoirs. Shown below is a SolidWorks model of the water tunnel inlet and outlet reservoirs and the viewing test section.
Proof of Concept:
The control system for the water flow would have been the proof of concept for the project but the cost hindered the idea. Instead, the honeycomb used for laminarization of the water flow was tested for the proof of concept. This is the second most difficult task that the team will undergo, so testing which honeycomb design will laminarize the flow most efficiently deemed to be a good idea. It gives the team an idea of a limit to how fast the flow can actually be controlled and laminarized at a smaller scale. The honeycomb contraption was created by connecting pieces of PVC pipes together to Tupperware that served as a water reservoir. Figure 1 displays the SolidWorks model used to create simulations of flow through the pipe and honeycomb.
Fig. 1: SolidWorks model of the proof of concept design.
Water Works tested two different materials, cloth mesh and standard straws, to simulate possible honeycomb designs. To give a reference sample, Figure 2 shows the flow of water through the pipe without a honeycomb. The mesh was attached to the front end of the pipe to allow the water to flow past it while the straws were stuffed along the inside of the pipe. Figure 3 shows the flow being laminarized by the straw honeycomb design.
Fig. 2: No honeycomb flow through pipe.
Fig.3: Straw honeycomb flow through pipe.
Proof of Concept Results:
The straw honeycomb performed better than the mesh honeycomb. The flow was significantly slower than the absence of a honeycomb. The flow is visually slower since the flow took up the full cross sectional area of the pipe as well as taking longer to empty the reservoir. This is also true for comparison between the mesh honeycomb and the straw honeycomb.
Phase II: Design Outputs
The purpose of Phase II was to develop product designs and document the design specifications.
“Mechanical Assembly Drawing 03-01-1”
Fig. 4: Drawing of hardware assembly.
Fig. 5: Isometric view of acrylic top.
Fig. 6: Simple block diagram of control system.
Fig. 7: Full project from Innovation Day.
Fig. 8: Final Draft of poster used on Innovation Day.
Unfortunately, the media video was unable to cooperate with the WordPress website, so an embedded video player is not provided but the file is ready to download via the link directly below.
Phase III: Verification and Validation
The purpose of Phase III was to provide the team with verification and validation of all design outputs set in Phase II.
The original plan was to plug the project into a 30 A outlet inside the basement of the Palmer Engineering Building. The reason for this is the plug that comes with the team’s original 1.5 HP pump. Because of this limitation, the project could not be tested at Ian Mook’s house. The project would then be filled to a comfortable level listed on the team’s documentation. After safely turning on the pump, the arduino, and the speed controller, the testing would begin. Originally designed we would try maximum flow speed, and then bring it down to the slowest possible until not enough water would be travelling through the pump. Next the drain valve would be tested for the drain time to estimate total clean up time.
The project could not be tested inside of Ian’s house as stated above. However during the project presentation with Dr. King within Palmer Engineering, the speed controller arced and was destroyed. This was also compounded with numerous leaks within the sealing of the acrylic top. It was hypothesized that air bubbles weakened the sealing job of the tunnel and allowed water to pass through. The team needed to reconvene at another time to repair the project before actual testing could occur.
Phase IV: Introduction Into Manufacturing
Purpose of Phase IV is to finalize all documentation, drawings, and design concepts for a production release.
The team assembled the frame first as to have something to design around. It was leveled and all fittings were tightened. The castor wheels were placed on at a later date. The polypropylene sheet is shown below, Melinda and Ian are drawing the acrylic top so that Jake can bore into the sheet to make a slot/slit for the tunnel. The brown sheets are the acrylic pieces, all cut to size for the tunnel itself. Once the sheet was bored into, it was then drilled so it could be bolted to the wood board also found in the image below. The acrylic was then glued to the polypropylene sheet and finally sealed the next night. In between the curing of the two adhesives, another wood board was mounted to the bottom piping assembly with the utilization of U-bolts so that the pump could be mounted. After this two holes were cut into the sheet assembly for the inlet and outlets.
The polypropylene sheet along with the connected wood board were then mounted to the top of the frame with the use of more U-bolts. Once fastened, the fabrication was nearly complete. The PVC tubing and pump assembly were left before final completion. PVC was cut to the appropriate lengths along with fittings to create right angles for the tubing. The PVC was then glued together, threaded into the pump, and carefully sealed to the inlet and outlet.
Finally, the castor wheels were mounted to the frame, holes were then drilled for the screws to keep the wheels fastened. After most of the drilling was complete, the bits broke and new ones were acquired to finish up.
Fig. 9: Melinda, Ian, and Jake assisting each other with the fabrication process.
Fig.10: Determining the plan of action.
Fig.11: Setting up the boards to finish the outline.
Fig.12: Vacuuming stray pieces leftover from machining and drilling.
Technologies used to manufacture prototype:
Multiple tools/hardware were used, such as: socket wrenches, a drill with associated bits for machining of polypropylene sheet, allen wrenches for securing the steel tubing, rulers/straight edges, hacksaw for cutting the acrylic top down to size, silicone for sealing, aquarium glue to keep the acrylic together, U-bolts/screws for fastening of boards to frame, fittings to link tube steel together, and pipe glue to permanently bond PVC pipes to one another.
Success of project:
The project was not fully tested, other than putting the hardware together and programming the arduino, with this in mind the success of the project is inadequate. The water tunnel is put together and can be dismantled and assembled again with relative ease. However, because of the leaks that plagued the project, it was never discovered whether the flow of the water would be enough with the new pump. With the use of theory and equations the pump seems adequate while the honeycomb has been tested as a part of the proof of concept found above. This research has led the team to believe the water tunnel would work if it were not for the leaks.
Future goals with design:
First, the acrylic top would be all one piece specially drafted/designed for water tunnel applications to disallow the issue of leaks. Also, wood boards would either be laminated/water-proofed or completely avoided as they have warped slightly from water exposure. A smaller/lighter frame would be designed and tested to allow for easier transport between buildings. If a larger budget was available, most of the tunnel would be drafted and then outsourced while the team would assemble the pieces. Also, a certified electrician would be hired/contracted to wire the pump and the speed controller.
Jacob Wik is a senior Mechanical Engineering student at the University of Nevada, Reno. Born and raised in Modesto, California. Jacob will be graduating from the University in Fall 2016 with Bachelors of Science in Mechanical Engineering. He currently is an intern at IGT who wants to continue his career there after he graduates.
Melinda Kinner is a senior Mechanical Engineering student at the University of Nevada, Reno. Born and raised in Las Vegas, Nevada. Melinda moved to Reno in 2012 to attend the University and study Mechanical Engineering. Through her college career she has worked for the University Engineering department and will be graduating in the Spring of 2016 with a Bachelor of Science in Mechanical Engineering.
Patrick Chow is a senior Mechanical Engineering student at the University of Nevada, Reno. Born in the Philippines, Patrick moved to Las Vegas, Nevada at the age of seven. After graduating from high school he moved to Reno to attend the University in August of 2012. Patrick will graduate in Spring of 2016 with his Bachelor of Science in Mechanical Engineering. He will be working for PepsiCo after graduation. In his free time Patrick enjoys playing basketball, hiking, and weightlifting.
Ian Mook is a senior Mechanical Engineering student at the University of Nevada, Reno. Born and raised in Sacramento, California. He came to the University in 2012 and will be graduating in Spring 2016 with his Bachelors of Science in Mechanical Engineering. In his free time he enjoys being outdoors and has worked as a ski instructor throughout college. After graduation Ians future goal is to pursue a career in renewable energy.
Wilbert Kemp is a senior Mechanical Engineering student at the University of Nevada, Reno. Born and raised in Las Vegas, Nevada. Wilbert will be graduating from the University with a Bachelors of Science in Mechanical Engineering in Spring 2016. Throughout his college career he has worked engineering internships where he has gained a variety of experience. In his free time Wilbert enjoys crossfit and short walks.