Coeficiente de carga cinética (k) em tubo emissor

Abstract

The aim of this study was to evaluate different estimation models of kinetic head coefficient (k) of an emitter tube. Four different longitudinal sections of Rain Bird XF-SDI emitter pipe, 16 mm nominal diameter with emitters spaced at 0.3 m and nominal flow rate of 2.27 l h-1 , were used. Sections had the same length (10.2 m), pressure taps at the extremities, and 34 sealed emitters. Were performed 229 observations of simultaneous values of flow, water temperature, and difference of total head between pressure taps. It was observed that the values of the kinetic head coefficient (k) tend to decrease with the increase of Reynolds number (Re). It was also noted that in the laminar and critical regimes, the absolute value of the rate dk/dRe is greater than its equivalent in the turbulent regime. Consequently, the models that incorporate the Reynolds number in the estimates of the kinetic head coefficient presented better results than the models that consider it only the obstruction caused by the emitter.