CFD Analysis of Personal Ventilation with Volumetric Chemical Reactions

Abstract

This article studies the concentration distribution in the microenvironment of a person and inhalation exposure in a typical office space when modeling first- and second-order reactions. First, wall adsorption of ozone and d-limonene and the resulting volumetric reaction are validated, and 2D computational concentration profiles are compared to the experimental results from Ito (2007b) with reasonable agreement. The validated model is then implemented in a 3D simulation of a typical office space with a seated thermal manikin, floor diffuser, desk, and optional personal ventilation (PV) system. Three cases were modeled: (1) no PV, (2) a PV system consisting of a single round jet, and (3) a novel low-mixing co-flow nozzle that directs fresh air toward the breathing zone (BZ). All concentration distributions showed significant differences compared to the traditional well-mixed assumption. The inhalation exposure was analyzed as an intake fraction (iF) and compared for the three cases. The co-flow nozzle was able to reduce the amount of reaction product inhaled by 5 times compared to a case without PV.