Author(s): Luca Moretti and Sofia Almeida

Abstract: Energy losses in pipe bends significantly influence the hydraulic efficiency of piping systems used in water supply, irrigation, and industrial fluid transport. Accurate estimation of these losses is essential for optimal design and operation, particularly where multiple directional changes are unavoidable. This experimental research investigates the effect of pipe bend angle on energy losses under steady, fully developed flow conditions. Four commonly used bend angles—30°, 45°, 60°, and 90°—were examined using a closed-loop experimental setup with controlled discharge and constant pipe diameter. Differential pressure measurements across each bend were recorded for multiple flow rates to determine the corresponding head losses and energy loss coefficients. The results reveal a clear and systematic increase in energy loss with increasing bend angle, indicating stronger flow separation, secondary circulation, and turbulence generation in sharper bends. Statistical analysis, including one-way ANOVA and linear regression, was applied to evaluate the significance of observed differences and quantify the relationship between bend angle and loss coefficient. The findings demonstrate that bend angle is a statistically significant factor affecting energy loss, with 90° bends producing substantially higher losses compared to gentler angles. Regression analysis confirms a strong positive correlation between bend angle and loss coefficient, supporting the hypothesis that geometric curvature plays a dominant role in dissipative mechanisms. The experimental results show good agreement with classical hydraulic theories and previously reported empirical correlations. This research provides experimentally validated insights that can assist engineers in selecting appropriate bend geometries to minimize head losses, improve energy efficiency, and reduce pumping costs. The outcomes are particularly relevant for small- to medium-scale pipeline networks where design simplifications often overlook local losses. Overall, the research emphasizes the importance of considering bend angle effects during hydraulic system design and contributes reliable experimental data for improving loss coefficient estimation in practical engineering applications.

DOI: 10.22271/27078388.2026.v7.i1a.60

Pages: 13-16 | Views: 24 | Downloads: 11

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