Sistematização de conhecimento para qualificação de pontas aspersoras para simuladores de chuva

Abstract

In agriculture, water acts in all physiological processes, biochemical and also in the thermal regulation of crops. Excess water in the form of rainfall generates losses of agricultural production, mainly due to the effects of water erosion, runoff and the removal of phytosanitary products after their application. In this sense, they are used as rain simulators to perform agricultural experiments simulating as characteristics of natural rainfall in a controlled environment. The different requirements for a simulated rainfall generation make complex the design of a generic model of rain simulator, with the selection phase of the sprinkler tip being one of the most important. In this way, the selection and dissemination in the consultation of technical catalogs, recommendations of manufacturers or adopt in their projects models of tips that have been validated in other conceptions of rain simulators. With this, it is what aims to systematize the knowledge of the tip qualification process for a simulated rainfall generation. A methodology for the realization of the project was structured in two stages: (i) experimental materials and methods, where they are carried out in the laboratory, analyzes experiments of three models of nozzle bridges, varying a height and pressure for the uniformity coefficient analyzer of the wet area of 1 m² and 0.36 m². Using a disdometer was determined on the drop size, intensity, fall velocity and kinetic energy of the different simulated rainfall generated. The set of information generated in the experimental stage allowed to identify the information of inputs, outputs, mechanisms and controls that are not available. (ii) The process was modeled using IDEF0, which consists of graphical representation of blocks connected by arrows that indicate the process flow in organization in a clear and systematic way. With an experimental analysis to verify for an area of 1 m², six combinations were classified with a good or excellent uniformity index, already for an area of 0.36 m², eleven combinations were classified as excellent or good. The results of the disdrometer indicate that the kinetic energy of the simulated rains generated by the three sprinkler tips are not similar to natural rains for their same origins. Regarding the model, with a US Source elaboration was defined twelve key points of the process, as well as a definition of four levels of detail of the model. The model consists of fifty-nine activities organized in the twelve nodes. It was concluded that the best wetness indexes of the wet area were obtained in the area of 0.36 m². It has been found that as droplets generated by the sprinkler tips analyzed do not reproduce the kinetic energy of natural rainfall for the same person. The developed model represents the qualification process in a clear and systematic way contemplating the important aspects in the qualification of a nozzle for the rain simulator project.