Aferição dos valores dos comprimentos equivalentes utilizados na determinação da perda de carga localizada

Abstract

Building hydraulic installations are the most important in the everyday of the human. It is thank for this systems that we could transpose water from one place to another, supplying the necessary the water that the human has, for this the same must always to be good dimensioned. In the correct dimensioning many factors must to be considered, between them is the head loss, that is divided in distributed and located. The objective this work was compare the results of head losses located, in the pipes of PVC, generated for special parts with the obtained in pipes with equivalent length to the part. The experiment was made in hydraulics laboratory of the Federal University of the Pampa/Campus Alegrete, on a bench pipes, with diameters of 20, 25 and 32 mm, where were tested the many special parts: curve of 90°, elbow of 45° and 90°, sphere register. For each part, was obtained the head loss generated for their equivalent length, through of product of linear head loss, determined experimentally in each diameter studied, for the respective value of equivalent length. The values of equivalents length used were obtained in the NBR 5626 (1998), to curve of 90°, elbow of 45° and 90°; and in Schneider pumps (2014), to sphere register. Also, were compared the values of distributed head loss, generated in each diameter of pipes, with the estimated for the formulas Universal and the Fair-Whipple-Hsiao. The values of head losses generated for the singularities were compared, with the head losses generated for the their respective equivalents length, through of the student test the 5% of probability of wrong. Through of results, was observed that the values of head losses, generated for equivalents length of curve of 90°, elbow of 45° and 90° are bigger, with significant difference, that the obtained experimentally, except to curve of 90° of 32 mm, where the head loss estimated is bigger, however without significance. Ready the sphere register presented head loss experimentally superior that the tabulated values, with significant difference. The distributed head losses, measures, were bigger to the superiors pipes, the same observed to the head losses estimated for the formulas. Conclude that the equivalents length, today used in the hydraulics projects are oversized, to curve of 90° (diameter of 20 and 25 mm), elbow of 45° and 90° (diameters of 20, 25 and 32 mm), however, are undersized to the sphere register (diameters of 20, 25 and 32 mm), thus, necessary the adjustment of this equivalent length.