Caracterização hidráulica do tape santeno.

Abstract

The objective of this research was to study the hydraulic performance of the SANTENO tape, which is a perforated flexible polyethylene linear pipe o f low density, with orifices made by laser radius. The SANTENO tapes used have a 28 mm commercial diameter, diameter of the orifices equal to 0.3 mm. with two pairs of orifices equally spaced in 1.2 meters. The orifices operate with pressures from 20 to 80 kPa. That were evaluated the following hydraulic aspects: characteristic equation of the discharge and pressure relationship; manufacturing variation coefficient of the orifices, discharge uniformity coefficient along the lateral lines; orifice discharge coefficient; pipe inner diameters varying the pressure, reach and height of the water jet; discharge as a function of the pipe length; maximum pipe lengths according to criteria previously established for discharge variations; and head loss along the pipe, using the equations of Flamant, Darcy- Weisbach and Hazen-Williams. the relationship between discharge and pressure was given by a power function, with a determination coefficient ( r ) equal to 99.91%. For the four tested pressures, the average manufacturing variation coefficient was 4.1%, which is considered excellent by the ASAE standard. The average discharge coefficients obtained for the orifices were 0.70, 0.69, and 0.70, respectively, for pressures equal to 20. 40, 60 and 80 kPa. The discharge uniformity coefficients presented values higher than 96%. The water jet reaches were 1.3 and 2.5 meters for the SANTENO tape 1 and 1.7 and 3.0 meters for the SANTENO tape 11, operating with pressures equal to 20 and 80 kPa. The inner diameters varied from 27.82 to 29.02 mm for a pressure change from 20 to 80 kPa. The pipe wa|£breakage pressure was 169.3 kPa. The discharge as a function of the pipe length varied from 11.25 to 7.09 1/h/m, data obtained experimentally for lengths from 10 to 200 meters and pressure equal to 80 kPa. The maximum lengths of the lateral lines, calculated according to the discharge variation criteria equal to 10, 15 and 20%, were 156.0, 182.4 and 204.0 meters, respectively. The SANTENO tape presented low values ofjiead loss along the pipe, where the results given by the Darcy-Weisbach and Flamant equations were very close; however, Hazen-W;illiams equation presented values inferior to the ones given by these others equations.