Estudo numérico e experimental de conforto térmico em cabine de ônibus

Abstract

The research around thermal comfort is motivated by the improvement of the quality of life, safety for activities that require attention, energy efficiency, competitive differential for the industry, and various activities in which the human being is inserted. Computational fluid dynamics (CFD) can be used to improve the geometries and operating conditions of systems in order to improve thermal comfort and contribute to the advancement of science and technology. The work presents a numerical and experimental study of the thermal comfort of a bus driver's cabin, aiming to validate the numerical implementation as a method of analysis and improvement of this type of system. In the first part, this work presents a literature review, which demonstrates how thermal comfort has been approached in association with CFD techniques. In the second part, it is proposed to investigate, through numerical and experimental methods, the air flow, its speeds and temperatures, in the environment of a bus driver's cabin, in order to relate them to the thermal comfort in this environment. A commercial CFD code based on the finite volume method was used, and the results were compared with experimental measurements. The validation made it possible to define good modeling practices for the system in question. The determination of the thermal comfort indexes (PMV-PPD) and the fields of temperatures and air speeds allowed the elaboration of recommendations aimed at greater thermal comfort for the design of bus cabins. The developed numerical model presented good results observing the comparisons with the experimental measurements. The average absolute difference obtained for the temperature was 0.8 °C while for the air velocity it was 0.04 m/s. Through the numerical results, the PMV-PPD indices demonstrate that 92.33% of the individuals would feel comfortable with the environment, which represents a PMV index of -0.3582. The experimental results of average temperature and air speed demonstrate that 93.27% would feel comfortable with the environment, which represents a PMV index of -0.2882. The methodology adopted for the evaluation of thermal comfort through numerical simulations allows to provide comfortable environments to human beings through the study of improvements in different projects.