The displacement ventilation patterns in two parallel-connected chambers with a mechanical extraction device

Abstract

This research studies the mechanical extraction ventilation in two parallel-connected chambers. A buoyancy source is located in one chamber, denoted as the forced room, and there is an extraction device in the other chamber, denoted as the extraction room. Two chambers have their own connecting openings to the ambient in the parallel-connected model. This paper focuses on the displacement ventilation pattern with a mechanical extraction device in the steady state. The flow driving forces include the buoyant and inertia forces in the mechanically ventilated space. The buoyant force results from a buoyancy source, and the inertia force, or suction force, is due to the mechanical extraction device. In this research, two different flow regimes are found in two parallel-connected chambers depending on the control extraction flow rate magnitude, and the upstream forced chamber is found to have a certain maximum flow rate limit in this configuration. When the control extraction flow rate is less than or equal to the limit value, both of the forced and extraction chambers have the same flow rate as the control extraction flow rate and the supply fluid from the exterior only goes through the forced chamber into the interior space. However, when the extraction flow rate is larger than the limit value, the enhancement flow rate of the forced chamber is more than the maximum flow rate limit, and the extraction chamber starts to bring some complementary flow rate from the exterior.