Methodology for Determining the Emitter Local Head Loss in Drip Irrigation Systems
José Henrique Nunes Flores, Lessandro Coll Faria, Osvaldo Rettore Neto, Adriano Valentim Diotto, Alberto Colombo
Abstract
Precise estimation of local head loss (hl) remains a challenge for the hydraulic design of drip irrigation. This study develops a robust protocol for estimating the emitter hl based on the Borda-Carnot principle. The method requires cross-sectional flow area measurements with and without emitter obstruction and a contraction coefficient, which is determined by the empirical relationship of the obstruction ratio. For comparison purposes, cross-sectional flow areas were also measured with a profile projector, which resulted in absolute deviations lower than 2.6%. Observed and predicted single-emitter hl deviation values were consistent with previous studies; the three examined emitting pipe types had deviation values of −6.67%, 21.6%, and 1.07%. Thus, the proposed methodology for estimating the cross-sectional area can be applied without compromising hl estimates using a single flat inline emitter operated by the proposed semiempirical model.