Undergraduate Internal Flow Pipe Friction Laboratory

Abstract

Hydrodynamics laboratory experiences have supported the United States Military Academy’s civil and mechanical engineering programs for nearly 50 years. A recent effort revitalized and significantly improved the pipe friction hydrodynamics laboratory, a system originally built by the U.S. Army Corps of Engineers Waterways Experiment Station in the 1950s. The experimental apparatus includes a 3 hp electric pump capable of delivering a steady flow of liquid up to 5.1 lbm/s fed from a 100 gallon (US) reservoir. The test section is a horizontal copper pipe of 0.75 in diameter which issues fluid into a transparent, plastic visualization chamber. Mineral oil is the working fluid, chosen for its favorable physical properties that enable a broad range of flow regimes for data analysis and flow visualization. The test section is instrumented with digital pressure gauges and an ultrasonic flow meter, installed as part of the revitalization project. A collection tank on a mass scale provides a manual method for estimating flow rate during experimental trials. The improved laboratory significantly expands the range of data that may be collected, with students now able to accurately measure pressure, temperature, flow rate, and pipe geometric data. Students compute Reynolds number to characterize flow regime, estimate pressure gradient, and predict the friction factor given an estimate for the pipe’s roughness coefficient for several flow rates. A pre-laboratory exercise requires students to derive a functional form of the steady-flow mechanical pipe flow equation and employ dimensional analysis to identify the non-dimensional parameters required to achieve dynamic similitude. The upgraded laboratory offers a relevant, comprehensive application to deepen students’ conceptual understanding of internal fluid flow, hydrodynamics, and modeling and similarity principles.