Uniformidade de aplicação de água de equipamentos autopropelidos de irrigação com aspersores de perfil radial triangular, elíptico e retangular

Abstract

RESUMO:Este trabalho apresenta resultados de simulações digitais da uniformidade de aplicação de água de sistemas autopropelidos de irrigação, para a condição de ausência de ventos. Nas simulações foram considerados aspersores com perfis radiais de distribuição de água tipo triangular, elíptico e retangular, operando sob diferentes combinações de ângulo de giro (de 180 até 360º) e espaçamento entre carreadores (de 0 a 100% do diâmetro molhado -DM). Os resultados das simulações foram apresentados em três grupos distintos, cada um representando a mesma forma geométrica do perfil radial de distribuição de água. Independentemente do ângulo de giro, os melhores valores de uniformidade foram obtidos com espaçamentos menores que 45% e entre 55% e 70% do DM para o perfil radial triangular e com espaçamentos menores que 50% e entre 70% e 90% do DM para os perfis radiais elíptico e retangular. Para os três perfis radiais, ângulos de giro do aspersor entre 180 e 230º geram maiores valores de coeficiente de uniformidade. PALAVRAS-CHAVE:simulações digitais, ângulo de giro, espaçamento entre carreadores. WATER APPLICATION UNIFORMITY OF SELF-PROPELLED IRRIGATION EQUIPMENT WITH SPRINKLERS PRESENTING TRIANGULAR, ELLIPTICAL AND RECTANGULAR RADIAL WATER DISTRIBUTION PROFILESABSTRACT: This study presents digital simulation results of water application uniformity of selfpropelled irrigation systems, under windless conditions. In the digital simulations, we considered sprinklers with triangular, elliptical and rectangular radial water distribution profiles, working under different combinations of angle of rotation (from 180º to 360º) and spacing between carriers (from 0 to 100% of the wet diameter -WD). Simulation results were presented in three distinct groups, each one representing the same geometric shape of the radial water distribution profile. Regardless of the angle of rotation, the best values of uniformity were obtained with spacing lower than 45% and between 55% and 70% of WD for the triangular radial profile, and with spacing lower than 50% and between 70% and 90% of WD for the elliptical and rectangular radial profile. For the three radial distribution profiles, the sprinkler angles of rotation which range between 180º and 230º generate higher values of uniformity coefficient.

Uniformity of Precipitation and Radial Profile of the Super 10 Sprinkler at Different Operating Pressures

“…Compared to typical behavior found in the literature for the geometric shape of the curve formed by the radial profile (triangular, rectangular and elliptical) cited by Prado et al [26], it was not observed for the sprinkler Super 10 in Figures 4-6, any of three behaviors, but the combination of all. Similar behavior was observed by Stambouli et al [27] using the sprinkler RC130-BY manufactured by Riegos Costa.…”

Asymmetric Wetted Sector Angle in Water Distribution of Traveling Gun Irrigation Systems

“…As observed by Prado et al (2012) and presented in Figure 4, in the strip spacing range (60 to 70% of the WD) indicated by manufacturers of traveler irrigation machines, sprinkler wetted angles from 210 to 330º, symmetrically adjusted to the travel path (β = 0), give CU values less than 80%. However, some asymmetry adjustments, especially for wetted angles of 270, 300, and 330°, may considerably increase the CU values (Figure 4).…”

“…On the other hand, for a wind speed condition of 1.5 m s -1 , regardless of wind direction, water distribution uniformity improves in the irrigation strip widths around 70% of the WD (Figures 5, 6, and 7). According to Keller & Bliesner (1990) and Prado et al (2012), water application profiles transverse to the travel path with uniform or rectangular shapes result in high CU values for spacings near the WD for no-wind conditions.…”

“…Keller & Bliesner (1990), considering that gun sprinklers have an almost uniform radial profile, recommend for under very calm wind conditions an irrigation lane spacing of 80 to 90% of the wetted diameter (WD) and sprinkler sector angles from 210 to 240º. Prado et al (2012), when studying the theoretical geometric shapes (triangular, elliptical, and uniform) of radial profiles from sprinklers working in traveler irrigation machine systems, found that wetted angles from 240 to 330º associated with strip spacing between 50 and 80% of the WD, provided low water application uniformity values.…”

Correlação Da Uniformidade Da Lâmina D’água De Um Autopropelido Sob Lançamento Oblíquo

“…Prado et al (2012) observaram que independentemente do tipo de perfil radial de distribuição de água, ângulos de giro próximos de 270º proporcionam baixos condições de campo. Porém, necessitam de alta pressão de serviço e, consequente, elevado consumo de energia, além de terem a uniformidade de aplicação de água muito afetada pelas condições de operação, em especial pelo vento (BERNARDO et al, 2008).…”