CFD Simulation of Head Loss in Channels with Sudden Change of Section: Comparison with Literature Correlations

Abstract

Empirical correlations for determining head loss in piping systems have been crucial in the design of complex installations, provided the validity ranges (Reynolds number, temperature, pressure, etc.) are respected. However, these ranges are often poorly defined. It is also common to assume that the total head loss is the sum of individual losses, even though these fittings are tested under conditions of fully developed flow. This study employs computational fluid dynamics (CFD) simulations to evaluate head loss in channels with contractions and expansions of different aspect ratios (L/H). The results show excellent agreement between CFD and correlations for isolated contractions and expansions. Additionally, it is observed that the total head loss is not simply the sum of isolated coefficients unless the L/H ratio is high, allowing the flow to redevelop before reaching the next area change.