Source: Ricardo Mejia-Alvarez and Hussam Hikmat Jabbar, Department of Mechanical Engineering, Michigan State University, East Lansing, MI The purpose of this experiment is to demonstrate the application of the energy conservation equation to determine the performance of a flow system. To this end, the energy equation for steady, incompressible flow is applied to a short pipe with a gate valve. The gate valve is then gradually closed and its influence on flow conditions is characterized. In addition, the interplay between this flow system and the fan that drives the flow is studied by comparing the system curve with the characteristic curve of the fan. This experiment helps understanding how energy dissipation is used by valves to restrict the flow. Also, under the same principle, this experiment offers a simple method to measure flow rate using the pressure change across a sharp entrance.