A Modular Water Bench and Fountain Design Project for an Undergraduate Fluid Dynamics Laboratory

Abstract Many educational supply companies provide equipment designed for students to observe fluid phenomena and record numerical data for subsequent analysis, with the aim of verifying existing empirical data, such as what is presented in the Moody diagram. However, students may not be motivated to think critically as they work with prefabricated experimental equipment if their objectives for experimentation are merely to replicate existing data. A laboratory pedagogy that values inquiry-based instruction is under development at University X to satisfy ABET Outcome 6: An ability to develop and conduct appropriate experimentation, analyze and interpret data, and use engineering judgment to draw conclusions. To do so, there is a need for laboratory equipment that provides flexibility for students to experiment with an array of flow devices such as pipes, elbows, pumps, valves, and measurement devices such as differential pressure transducers and flowmeters. A modular water bench has been developed with a design project in mind whereby student teams design and build a piping system that draws water from a fixed-head reservoir and splits the flow, sending it to two fountains. Unique performance criteria related to achieving certain flowrates in the two fountains are provided to each team. The water bench is about eight feet in length and three feet wide. The bench includes a sump from which a submersible pump fills a fixed-head overflow reservoir on a rolling tower. The rolling tower has a footprint that takes up two of the eight feet of length of the water bench. Students work on platforms made of perforated stainless steel with square surfaces of three-foot edge length. Therefore, the bench can be converted to arrangements of platform-platform-tower or platform-tower-platform to allow a single student team to work on a 6-foot platform or two teams to work simultaneously on a 3-foot platform, respectively. In addition to the overflow reservoir, the tower features two Coriolis force mass flowmeters and two variable DC power supplies, which can be used to power small DC pumps. The design project is a four-week, eight-hour activity. The first three weeks are devoted to empirical measurements of major and minor losses, as well as an empirical investigation of fountain-based levitation. Students are provided with sections of clear, rigid PVC tubing, a large suite of push-to-connect fittings, specially made pressure tap fittings, needle valves, and a DC pump. Students are challenged to perform measurements to a degree of quality that can be trusted for application in their final system design. In the fourth week, students deliver a complete technical report of their measurements, as well as a complete design of their fountain network. No valves are allowed during week four. The students are challenged to perform predictive modeling of the flow resistance through each branch of the fountain network such that the precise ratio of flowrates to the two fountains is achieved. The team builds their system, their teaching assistant tests it, and they write an engineering letter summarizing the success or failure of their system.