Computational fluid dynamics study and evaluation of different personalized exhaust devices

This article investigates the performance of three different types of personalized exhaust devices. A top-personalized exhaust, which is a round device just above the human head; a shoulder-personalized exhaust, which consists of two local exhaust devices installed at the chair just above shoulder level; and a chair-personalized exhaust, which is at the upper part of a chair just behind the human head, were simulated, evaluated, and compared numerically using the computational fluid dynamics method. Two seated occupants representing healthy and infected manikins equipped with two types of personalized ventilation devices in a simulated consulting room in a healthcare center were modeled. Two indicespersonalized exposure effectiveness and inhaled fractionwere introduced to evaluate the improvement of general inhaled air quality after adding different types of personalized exhaust devices and to compare the performance of different kinds of personalized exhaust devices with respect to the healthy manikin's exposure to exhaled contaminated air. The computational fluid dynamics models were validated with a set of experiments conducted in an environmental chamber. The results indicate that all the three personalized exhaust devices might be able to reduce the transmission of exhaled air between occupants. The lowest inhaled fraction was achieved by the combination of a vertical desk grill and a top-personalized exhaust. However, only the shoulder-personalized exhaust device has the potential to improve the amount of personalized ventilation air in the inhaled air.