Closed Circuit Water Tunnel

Water tunnels have been around for decades, instrumental in developing hydrodynamics and cultivating interest in fields such as fluids. However, many of these projects are very expensive, large, and have a massive learning curve to operate and learn about these machines. With our project, we want to fill in the gap for a low cost, easy to use, and portable water tunnel used by small businesses and lesser funded educational institutions. This solution will provide the gap in resources that these places similar to a food desert in urban areas. Due to a lack of resources, they cannot have access to that kind of equipment. They could hinder those who would benefit significantly from having access to this type of equipment. The significant factors that are affecting our design are, firstly, the cost of the water tunnel. Many companies make large industrial water tunnels that are incredibly accurate and high quality. However, the large price for these top of the line products is a barrier for smaller businesses from purchasing these. Our focus is on cheaper materials that can provide similar quality to these professional products. The second factor we are looking at is the size and portability. One of our main targets to sell this product to are school districts and different high schools.

• Charlotte Pipe - (50ft)
• 2 in. 40 90-Degree S x S Elbow Fitting - (5)
• PVC Adapters - (2)
• 3D Printed Honeycomb - (1)
• 3D Printed Water Tunnel Entry - (1)
• 3D Printed Water Tunnel Exit - (1)
• 3D Printed Object Mount - (1)
• Water Pump - (1)
• Viewing Area Walls - (3)
• SPHERICEL® Cosmetic Microspheres - (1)
• Expert Gardener Metal Single Valve Shut-Off Hose Connector- (1)
• Expert Gardener Push Fit Male Mender - (1)
• Chest Latches - (1)
• Weather Stripping - (1)
• 2 in. Soft Rubber Rigid Caster - (2)
• 2 in. Medium Duty Gray TPR Swivel Plate Caster with Brake 90 lbs. Weight Capacity - (2)

• EPOXY Resin Crystal Clear 32 oz Kit - (1)

The prototype of the water tunnel is a SolidWorks representation of our final assembly. All of the joints and pipes will be connected using Flex Seal. The main advantage of using this method is that when applied, Flex Seal forms a watertight seal, which is much easier to apply than caulk or putty. Each of the connecting parts will also be secured using a threaded couple also made of PVC pipe. The assembly consists of piping made out of a two-inch PVC pipe, the viewing area made out of plexiglass. These 3D printed parts will be made of ABS plastic. The viewing area's top will consist of a sealed hatch in order to prevent any change in pressure throughout the cycle. The final product will be secured to a wooden base with vertical supports that will run along the cycle's entirety. This option will be the cheapest and most secure form of stabilization.

Prior to constructing the Closed Circuit Water tunnel, ensure that you have all of the stated materials from the introduction in order to properly assemble the device. Once all the materials have been collected then cut and shape into proper dimensions.

The 3D Printer will be utilized when constructing the viewing area entry, viewing area exit, the honeycomb, and the object mount. Each of these objects will be constructed out of PLA plastic. Due to the size of the printer, the entrance and exit has been designed to be printed into smaller pieces which are meant to be conjoined at a later date.

Due to the printed parts being made out of PLA plastic, the objects are difficult to mend. The best option to conjoin the segments with minimal leakage/damage is to utilize a combination of Krazy Glue and Flex Seal. After the plastic has been joined, add metal supports on the corners of the 3D printed parts to ensure a level surface and additional structural integrity.

Attach the drain valve on the side of the Viewing Area Exit near the bottom. The reason for this is to help fill and empty the tunnel with minimal pressure loss. Ideally, the drain should be one that you are able to connect to a garden hose for ease of emptying the tunnel without causing a slip hazard due to water leakage. The valve used on our tunnel came in two different pieces, one to secure the inside and one on the outside. This was the most secure and was the best option for reducing pressure drop.

Once the entrance and exit have been completely constructed, coat the interior with an epoxy to ensure that there will be no water leakage/damage. Just like the PLA parts were attached and sealed with Krazy Glue and Flex Seal, attach plexiglass sheets to the sides and bottom to complete the view area and seal them using flex seal. After this is complete, run water through the view area to test that it is water tight and its structural integrity.

Apply chest latches on the opening of the top running perpendicular to the flow of the water. Once this is done, place weather-strips along the inside lip of the top opening in order to ensure there is no pressure drop and the top remains water-tight. On the bottom of the viewing area, simply hot glue then caulk the plexiglass into the opening on the bottom since it will not be removed at any time. Once the top and bottom have been attached to the viewing area, the plexiglass walls will be slid into the top and bottom grooves.

Cut pipes to desired lengths and attach segments using pipe adaptors and elbows.

Firstly secure the water pump to the wooden base of the water tunnel assembly. Once it has been attached, then use 2 inch PVC couplings and fitting to connect the Charlotte Pipe. Once the piping and the couplings are connected, utilize a combination of superglue, caulk, and Flex Seal in order to ensure there is no water leakage and that they won't come undone when water is being pumped through.

In a similar manner to the water pump, attach the PVC pipe to the view area entrances and exits using super glue. Check for water tight seal after applying Flex Seal.

Cut wood pieces to desired length and attach to create platform to support the entire water tunnel. This base must be lightweight to make it transportable, yet sturdy enough to withstand the demands of a busy school or workplace.

To secure the water tunnel to the base first, you need to measure out on the pipes and view area to see where points are that need to be supported. Mark those out onto the base for further reference. Now measure the height required to support it. Take a saw or woodcutting implement and cut the amount of supports you need to the required different heights. Taking the marks, you measured out an earlier drill in the supports to the base. Now set the piping on top, secure the metal U bracket, and drill those into the top of the supports to drill it in.

The water tightness of the water tunnel is vital to the successful use of the product. Once you know that all joints are properly connected with PVC glue and take your sealant of choice, we use caulk but found that the spray-on flex seal ended up working the best. Another point of probable leakage is with 3D printed pieces and spraying the flex seal over them seals them up completely. Once spraying all joints, you can test by filling up the system will water to check for any leaks.

The easiest way to transport the water tunnel assembly is to place the base on a mobile cart. Before purchasing the mobile cart ensure that the dimensions are wide enough to support the base without safety precautions. Place the cart running longways to make it easier to transport through doorways and hallways. Before moving the cart, make sure that the cart is placed under the center of gravity, for there won't be any chance of it falling off.

When filling the tunnel up with water use a regular garden hose and fill from the top of the viewing area. Once the water level reaches approximately three-fourths of the viewing area's height, cut off the flow of water and remove the hose. Before running the pump, wait a couple of minutes to ensure that the water has made it around the tunnel. If the water level drops due to this, reattach the hose and continue to fill. This will ensure that the water is evenly distributed throughout the pipe and that the flow is as laminar as possible.

Once the tunnel is filled with water, insert sphericel or another suitable microsphere replacement and plug in the water pump to activate the water tunnel. The reason for this step is to be able to visually asses the water movement over desired testing objects.