Características hidráulicas e da distribuição de água do microaspersor Dan Sprinkler 2001.

Abstract

The purpose of this research was t o determine the hydraulic characteristics of the micro-sprinkler Dan 2001. Therefore, were analyzed the following aspects: manufacturíng variation coefficíent; pressure and discharge relationship; water application profile; and the precipitation dístribution surface, The manufacturíng variation coefficíent found was 0.044, which is considered excellent according to the ASAE classífícation. For the fitting of the measured pressure and discharge data, were tested 25 mathematical equations. ín the fitting of ali measured data, that is, including also the emitter selfcleaning zone data, the paraboíic equatíon presented the best fit with a determination coefficíent (R2 ) equal to 77.87%, however, for the power equation the fitting was 72.38%. It was verified that the hysteresis phenomenon practically díd not occur and that the microsprinkler is considered a self-compensating emitter on the pressure íntervaí from 136 kPa to 300 kPa. For this pressure ínterval the best fitting was gíven by the normal logarithmic function with a 99,62% fitting, whiíe the power function fitting was oníy 4 3 . 7 3 % . The water application dístribution profile was considered satisfactory, presenting an effectíve radíus equal to 2,25 m. The isohyets and the three-dimensional dístribution profile graphs exhibited satisfactory soil surface water application. However, the Chrístiansen and Hart uniformity coefficíents were, respectively, 6 1 . 1% and 5 7.7%. Obviously, these coefficíents were relatively low because in microsprinkle there is not overlapping, and so, according to the surface dístribution graph, these coefficíent values mean a satisfactory dístribution uniformity. Besides, the precipitation variation coefficíent proposed by Sadan and Shani was equal to 42.5%, which is considered a reasonable value for micro-sprinkle.