The cost of a quality water tunnel can range anywhere from thousands to tens of thousands of dollars. C.A.R.G.G Industries was tasked with building a quality water tunnel for university research purposes that can be transported between labs. The water tunnel must create laminar flow through a viewing window, have an adjustable flow rate, and maintain a velocity between 0 and 1 m/s. To compete with existing water tunnel designs the team’s water tunnel must be constructed with a budget of $1000. These parameters allow C.A.R.G.G. Industries to create a very competitively priced water tunnel while allowing the user to control water flow speed.
Proof of Concept
The team’s proof of concept was broken down into three main parts; how to vary the flow rate of the water, how to achieve laminar flow from the pump to the viewing area, and how the flow speed will be measured. To control the flow rate of the water, a compatible speed controller was purchased alongside the pump to vary the power output. To test how to make the flowrate laminar, different honeycomb pattern diameters were 3D-printed and will be used in conjunction with the team’s pump and controller to determine which honeycomb dimensions fits the team’s criteria. To read the flow rate, an incline manometer and pitot-static tube were purchased. The pressure difference is shown by the incline manometer, which is connected to the pitot-static pressure tube via tubing. Using Bernoulli’s equation, a velocity difference can be calculated through the pressure difference observed by the manometer. All three concepts will be tested at the same time in a prototype tank donated by UNR.
Purpose: The purpose of Team C.A.R.G.G.’s water tunnel design is to design a device to observe aerodynamic and fluid dynamic properties at a fraction of the cost of water tunnels currently available on the market. The water tunnel designed most beneficial to the consumer that work in a learning environment as they can use it as a live demonstration of aerodynamic and fluid dynamic properties. It is also useful in the way that it is economical and durable as long as proper care and maintenance is observed allowing for long term use.
To ensure the team does not go over the $1000 budget, each component will be analyzed for cost and effectiveness, giving priority to purchasing of the best materials that deal with safety and effectiveness. The water tunnel will be constructed to fit through a standard door of 6’ wide and 8’ tall and affixed with locking wheels to ensure portability and safety. The device will include an instructional manual on operation and maintenance to ensure safety and prolong the life of the device. The walls of the water tank will be made with ¼ inch thick plexiglass and sealed carefully to ensure no spillage occurs. Device will have a drain at the bottom of the tank to dispose of the water when not in use. Bright yellow warning labels will be printed and placed on the water tunnel to warn of the hazard of drinking the water in the tank and to warn the user to only use water for the tank. The tank will have a mark showing the max amount of water that the tank can contain. The team will attach a disclaimer that shows the device as standalone equipment and a warning label to lock the wheels when the device is not being transported. The team’s logo will be printed on stickers and placed on conspicuous areas of the water tunnel.
The more technical characteristics of the water tunnel involves the speed of the water and reading of said speed. The pump purchased is approved to work with a standard wall outlet with a ground fault circuit interrupter. The water flow will be made laminar by using a honeycomb to slow down the flow rate. The flow output will be adjusted through the use of a variable speed controller. The pump and variable speed controller must be wired professionally and in compliance with the NEC wiring codes. Using a manometer, the user will be able to observe the flow speed. Due to the manometer in use displaying the speed of the water in inches of water column, a conversion sheet to m/s will be included. The team has published a more detailed account of the design specification that can be found in the PDS.
The team was fortunate to have inherited a rolling frame for the water tunnel to be placed on from a 2016 UNR ME Capstone team. C.A.R.G.G. Industries cut out a wooden sheet and coated the sheet in a waterproof coating to avoid swelling from leaks. The wooden sheet was placed as a table top on the rolling frame for the rest of the components to rest on. The tank that is to hold water was cut out from acrylic sheets. The individual pieces of acrylic were bonded together using an acrylic cement that fuses the individual components together. Once all individual pieces of the acrylic were bonded together, the team used a silicone based epoxy to act as a second layer of security to prevent leaking from the water tank. The honeycomb pattern settled on by the team was purchased in sheets. Multiple, smaller sections of the honeycomb sheets were cut out to fit inside the designated area to laminarize water flow. Tubing was purchased in bulk to connect the pitot-static pressure tube to the manometer gauge. The tubing was cut in various lengths to determine the length that would best allow for positioning of the manometer for easy viewing.
Fig. 1: Individual components used to fabricate the final prototype assembly.
Fig. 2: Tank assembled using multiple acrylic sheets
Fig. 3: Submersible pump used to generate water flow.
Fig. 4: Stand fabricated to hold hose at supply end of water tank.
Fig. 4: Stand fabricated to hold hose at supply end of water tank.
Fig. 6: Honeycomb pattern used to laminarize water flow. Shown assembled in tank.
Fig. 7: Tubing connected to pump to return water from collection to supply end of tank.
Fig. 8: Pitot-Static pressure tube installed in tank.
Fig. 9: Pressure gauge connected to tubing to read pressure difference.
Testing and Results
C.A.R.G.G. Industries tested their water tunnel multiple times while preparing its prototype. The team’s water tunnel was designed to be a portable device for the use in classroom demonstrations.
The test plan for the product was to assemble all components and then let the device run for 30 minutes. The device was left to run to ensure all components would perform as specified for a long period of time. Testing includes varying the speed of the pump, through use of the controller, and checking to ensure the pressure gage value changes with the speed of the pump. Air bubbles were induced by the water supply hose to observe the laminarization of water when passing through the honeycomb pattern. The pump was then powered off and the drain was checked to verify that the water was able to drain from the tank. After draining of water the tank was then put into storage.
The team tested the water tunnel through running the device for 30 minutes with all components attached. The test were testing for the functionality of each component as well as its ability to achieve the required specifications. The team performed these tests a total of four times until the product was completely functional. The first test the team performed exposed that there was a leak in the tank which the team used silicone to reseal the tank. The second test the team found that the differential pressure gauge wasn’t holding a pressure difference due to the tubing not having a tight seal to the pitot static tube which the team used teflon to create a tighter seal. The third test and fourth test both ran smoothly demonstrating a complete prototype.
The mechanical engineering department at the University of Nevada, Reno needed a cost effective water tunnel to demonstrate fluid dynamic properties. C.A.R.G.G. Industries water tunnel was designed to fulfill the design requirements of being created for less than pre-existing models, being portable, maintain laminar flow for a long enough period to submerge a model for study, and have controllable flow rate with power supplied by a standard wall outlet. The designed prototype fulfilled all of these design and performance requirements. The design of the prototype will make it easier for instructors and small labs to be able to observe and demonstrate fluid dynamic and aerodynamic properties of objects through the use of a small and portable device. The team received a positive feedback from all users who tried the water tunnel as the device is simple and easily operated. The products design matched its purpose of allowing the user to easily demonstrate and visualize the fluid flow around a scale model object.
Meet the Team
Samuel Ankomah was born in Ghana, Africa but went to High school in Elko, Nevada. He is expected to graduate in May 2017 with a bachelor’s in Mechanical Engineering and a minor in Computer Science. Sam hopes to stay in Reno and pursue a career in his field of study.
Mauricio Rodarte was born in Sinaloa, Mexico, but raised in Reno since the age of five. Growing up he has always had a passion for all things mechanical, leading to him pursuing a bachelor’s degree in Mechanical Engineering. His anticipated graduation date is May 2017 and looking forward to the beginning of his career.
Adam Garcia is from San Jose, California, but was raised in Fernley, Nevada. With an expected graduation date of May 2017 he plans on pursuing a career in Mechanical Engineering with his bachelor’s degree in Mechanical Engineering.
Humberto Guzman-Martinez III
Humberto Guzman was born and raised in Reno, NV. A highly motivated first generation college student, he strives to exceed expectations and keep a solid network of contacts. His past community involvement which includes his establishment of a partnership with United Way of Northern Nevada for his service fraternity Omega Delta Phi, and internship for the City of Reno, has allowed Humberto to develop a strong leadership. Planning to graduate this May 2017, Humberto plans to pursue a career out of state and travel to gain ideas and experience to help him with his career.
Connor Cox is a Senior in Mechanical Engineering from Reno, Nevada. Connor’s academic accomplishments are shown with his achievement of the College of Engineering Dean’s list for both the 2013 and 2014 academic years as well as his membership in Tau Beta Pi; an Engineering Honor Society. Connor is currently, and has been for two years, an Engineering Intern at Haws Corporation. After graduation in May 2017 Connor plans on exploring different opportunities to continue building on his Engineering career.
Team C.A.R.G.G. Industries would like to thank the following for their support and guidance in this endeavor:
Matteo Aureli – Sponsor
Patrick Stampfli – Mentor
Humberto Guzman-Avalos – Manufacturing Support
Tony Berendsen – Manufacturing Lab
Nicholas Maus – Lecturer