Modelagem computacional da distribuição de variáveis ambientais em aviário ventilado à pressão negativa.

Abstract

In Brazil, the use of artificial conditioning systems in negative pressure in poultry houses is becoming increasingly common and in Paraiba, although at a slower pace, has been incorporated for making possible the correction of the microclimate inside aviaries. However, researches developed in the area of Rural Constructions and Ambience indicate the need to improve the efficiency of these systems instead of identifying the heterogeneous distribution of air throughout the building and the inadequacy of internal environmental data to the recommended ranges for the thermal comfort of broilers especially in the hottest times of the day. For these reasons, the efficiency of different constructive arrangements was evaluated in broilers houses, ventilated at negative pressure, by analyzing the distribution of air temperature (Tar), relative humidity (UR) and wind speed (Vv) and characterization of the thermal environment using the Temperature, Humidity and Air Velocity Index (ITUV). For that, a poultry house was instrumented for field data collection and diagnosis of its internal thermal comfort facilities; a computer model of reference was generated based on this aviary, using the software Autodesk CFD 2016; this model was validated; Three different cover arrangements (TiFiA- based on the prototype, with ceiling parallel to the inclined cover and fins, TiFisA- similar to TiFiA, excluding fins and TiFh- similar to TiFisA, with horizontal ceiling) were tested; the most efficient cover arrangement was selected and combined with two evaporative panel arrangements (TiFisA20L and TiFisA40L, with 20% and 40% of the area of the panels facing the East, respectively). It was concluded that: according to ITUV, the instrumented aviary, between 12 and 14 h, did not provide comfort to the adult poultrys housed, with Tar, UR and Vv values not pertinent to the recommended ranges; the CFD model for TiFisA was validated with Tar averages of 27.75 ± 1.35 oC collected in the field and simulated ones were 27.85 ± 0.55 oC, UR mean values of 83% ± 12% collected and simulated ones of 78% ± 3% and Vv means values of 2.35 ± 1.35 m.s-1 collected and simulated ones were of 2.50 ± 1.50 m.s-1; among the tested cover treatments, TiFisA showed to be the most adequate to the comfort of the broilers according to the distribution pattern of Tar and Vv; and among all the simulated arrangements, TiFisA was shown to be the most suitable for the comfort of the broilers according to the Tar distribution pattern.