The primary objective of this design project is to provide an opportunity for undergraduate students to integrate engineering measurements and modeling techniques to accurately predict a priori the optimum pump size, pipe diameters, and wall thicknesses of a pump and pipe system given specified flow rates and lengths of piping. A secondary objective of this design project is to provide students with an opportunity to improve team and technical skills while grouped into small teams. The teams are challenged to predict the pipe diameters and pump size used to serve two parallel branches of a piping system. The experimental apparatus is a pre-developed system that includes three different size pumps and the two branches of pipes with each branch having its own flange to accept different size orifices. The orifices are used to represent the optimum pipe diameters. Students are to determine the optimum pipe diameters through an analytical model of the system. The students also use experimental techniques to test and measure the specified flow rates and pressure drops of the system for different combinations of pumps. To add to the realism of this design experience, the students are given imitation money that is used to buy materials (orifice plates) and services (system test time, professor guidance, and engineering time). The final grades are based on the analytical model, results from the experiments, cost of the project, and the performance of the final pump and pipe system when compared with the analytical model. This design project provides students with a real life example of the design process and shows the importance of employing the engineering design process to the development of a functioning prototype system. One student team's analytical model predicted a total cost of $1,263, which includes the pump cost, present worth of the operating cost, and pipe costs. The size of the pipe to allow the specified flow rates of 10 liters per minute and 5 liters per minute through the two branches of the apparatus had inner diameters of 1.6 centimeters and 1.2 centimeters. In order to demonstrate this correct pipe size, the students created their two orifice plates with 4.4 and 6.3 millimeter holes. When placed in the apparatus, the students used their chosen pump to measure the flow rate across the two orifice plates. The team had flow rate of 9.0 and 6.1 liters per min, a 13% and 18% error respectively. Students noted that this could have been due to the specific and odd hole size needed for the orifice plate. A 0.76% change in orifice diameter would result in a 1.5% change in flow rate. Nine teams of four students completed this project in the spring semester 2010. Eight of the teams were able to produce flow rates within 30% of the target flow rate. Additionally six of the teams were able to predict the power consumption of the pump within 30%.
