Comparison of experimental results with empirical relationships for energy losses in pipe flow

Abstract

Estimation of energy losses in pipe flow is a prerequisite in designing pipe networks to verify the energy requirement in transferring fluid between two locations. There are two types of such energy losses namely: major losses which is caused by friction at the interface of pipe and the flow and minor losses which is caused due to local conditions such as sudden contractions, sudden expansions, and bends of the pipeline. In this paper, major and minor losses in pipe flow, calculated from empirical equations are compared with the experimental results using PVC pipes which is a popular commercial pipe category. For comparison on minor losses; Bend, Gradual contraction, Elbow bend, Gradual expansion, and 45 degrees bend which are widely used in distribution networks were used and coefficient of minor losses was used as a comparative factor. For comparison on major losses; PVC pipes with five different diameters were used and head loss vs Reynolds number variation was considered in the comparison. According to the results, the Blasius (1913) equation was found to be more accurate for actual flow, while using the Darcy-Weisbach equation found to be more predictive of the major head losses of water flow in PVC pipes.