MATOS, J. A.; http://lattes.cnpq.br/4949185130792167; MATOS, José de Arimatea de.
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.