Determining System Time Constant Through Experimental and Analytical Techniques

New experimental procedures are being developed to help students connect course theory to real-world systems.The time constant of a fluid system consisting of a tank, inlet flow, and outlet flow through a valve is determined by the resistance and tank area.The valve resistance is non-linear and depends on the flow rate and tank level.Both the time constant around an operational point and the average time constant through a range of operational points can be determined through experimental and analytical techniques.The time constant of an experimental liquid-level rig is determined by deriving a linear model of the system and experimentally determining the relationship between steady-state outlet flow rate and tank level.These analytical and experimental methods incorporate concepts mechanical engineering students learn in several core courses.Homework assignments and laboratory experiments exploring a physical system serve to engage students and help them make connections between course material spanning the mechanical engineering curriculum.