Optimum ventilation based on the ventilation effectiveness for temperature and CO_2 distribution in ventilated cavities

摘要

Numerical results obtained from the analysis of the conjugated heat and mass transfer of an Air-Carbon Dioxide mixture (CO_2) inside a ventilated cavity in turbulent flow regime are presented. Different configurations of the cavity were analyzed regarding the location of the mixture outlet gap in order to study the thermal behavior and the air quality inside the cavity and to determine a good ventilation configuration. Four different values for the CO_2 contaminant source (500,1000, 2000,3000 ppm) are considered. The air inlet gap is located on the lower side of the right vertical wall of the cavity. The inlet air velocity is a function of the Reynolds number (5 × 10~2 ≤ Re≤ 4 × 10~4). The location for the mixture outlet gap was considered in four different positions: Case A, the outlet gap is on the upper side of the left wall; Case B, the outlet is on left of the top wall; Case C, the outlet is at the middle of the top wall and Case D, the outlet is on right of the top wall of the cavity. From the results, it was concluded that, from a thermal comfort point of view and air quality, configuration D shows the best performance. In general, it is concluded that in order to obtain values that fulfill regulations of temperature and contaminant concentrations, it is required to have mixed convection with a Reynolds value of Re = 10,000.