Improving a Rainfall Simulator considering the uniformity coefficient as a key parameter

Abstract

Rainfall simulators are fundamental tools in storm analysis under the concept of physical modeling in a defined controlled space. This article addresses the improvement of a rainfall simulator according to the uniformity coefficient criterion. Based on this, improvements were proposed for the rain simulator at the National Hydraulics Laboratory (Peru) used for storm studies. Two testing phases were evaluated. First, the flow distribution by sprinkling from a nozzle over a 17.71 m² surface was assessed, considering three different heights above this area (2.5 m, 2 m, and 1.5 m). Then, the uniformity coefficient was analyzed for each test to estimate the nozzle spacing, which was determined to be 1.2 m. The second phase involved assembling a Fulljet 1/4HH-14WSQ nozzle grid with the calculated spacing and evaluating the uniformity of the spray flow generated for the three heights tested in the first phase. The results show an 8% increase in the uniformity coefficient compared to the rain simulator with 1.5 m spacing in the laboratory. The height range that produces a uniformity coefficient greater than 75% is between 2 m and 2.5 m above the study surface.