Laboratory Water Channel

Mission

Design, validate, and construct a high volume laboratory water channel to perform multi-disciplinary scientific experiments in macro-fluidics. These experiments include bluff body flow dynamics, particle sedimentation studies, and underwater vehicle research.

Specifications

Max Fill Volume: At maximum capacity, this water channel hold over 400 gallons of fluid.
Closed Channel Design: The water channel is designed to be filled completely, eliminating the air/water boundary layer and allowing for omnidirectional symmetric flow patterns.
Circulating Flow: Water is continuously recycled through the channel at flowrates which may exceed 2000GPM
Reynolds Number Control: Features are implemented to control both laminar and turbulent flow regimes

Starting Small

To demonstrate design principals and manufacturing methods, a small scale prototype was constructed at 1/5th scale using acrylic, PVC pipe, and 3D printing. This design featured a prototype diffuser and custom pump driven by a PWM controller. Prototyping in this way provided a low risk opportunity to test new ideas hands on and justify unique design decisions outside of theory. Although only partially functional, lessons learned from the development of the small scale device would go on to impact the full scale design.

Design

Detailed 3D models were developed in Onshape, a browser base CAD service. The heart of the water channel is its "test section", a 10ft long 0.5m x 0.5m acrylic passage through which flow is observed. At the inlet of the test section lies the diffuser which is designed to evenly distribute fluid exiting the pump through gradual expansion. The piping pictured is 10" SCH40 PVC chosen for its seamless integration with the pump.

Analysis

Ansys Fluent FEA software was used extensively to qualify and tune flow patterns generated by various geometries. Part of this research included flow stabilization and distribution to reduce fluid turbulence at the beginning of the test section. A diffuser and several contoured grids were developed and simulated to counteract unwanted flow profiles.

Construction

All construction and fabrication performed at RIT without the help of external contractors

3D Printed Parts

Both the outlet and diffuser sections of the test stand utilize a hybrid composite structure. In order to create precise contoured geometry necessary for controlling flow patterns, the shells of each component are printed in multiple pieces on the Big Rep large format 3D printer in PETG (Chosen for its toughness, availability, and chemical resistance).

Printed components are assembled using West Systems G-Flex epoxy resin. To make the parts waterproof and strengthen interlayer adhesion, the interior surfaces are laminated with a single layer woven fiberglass composite fiber and West Systems 105-206 Marine Epoxy.

Acrylic Sheets

The test section is made up of four individual 3/4" thick acrylic sheets. The sheets are held together using a tonghe and groove feature. Hardware mounting points are created using brass heat set inserts to create a strong wear resistant thread in the plastic. Each sheet is machined to size on the Shop Sabre IS-510 large format CNC table router using toolpaths generated in Fusion 360 CAM.

Acknowledgments

This project was made possible thanks to:

Research Advisor: Dr. Shima Parsa

Project Partner: Brett Kruse

Student Colleagues: Kurt Hann, Will Braun, and Jason Gonzalez

For more info on this project or to see current progress and experiments, visit our lab website

Soft Chaos Lab