History recovery and source identification of multiple gaseous contaminants releasing with thermal effects in an indoor environment

Abstract

Thermal transport and transient dispersion of pollutants emitted from two discrete strips within the displacement ventilation enclosure have been modeled numerically. Following the full numerical simulation of turbulent air flows, the inverse determinations of multiple pollutant sources were conducted by the use of quasi reversibility methodology. Direct simulation together with the turbulent streamlines and turbulent heatlines demonstrate that the enclosure flow pattern, enclosure air thermal level and heat transfer potential will depend on the interactions of external forced flow and thermal buoyancy driven flows, i.e., Reynolds number (2 × 10 3 ⩽ Re ⩽ 10 4) and Grashof number (10 6 ⩽ Gr ⩽ 10 10). In subsequent forward time and backward time modeling of airborne pollutant transports, temporal evolutions of enclosure average concentration and pollutant exhaust are shown to depend on the supplying velocity ( Re), thermal plume ( Gr), pollutant diffusivity (0.1 ⩽ Sc ⩽ 2), and the pitch between both sources (0.2 H ⩽ d PSL = d PSR ⩽ 0.7 H). Reverse time modeling of airborne spread has demonstrated that increasing the spread rate and the concentration sensitivity of airborne pollutants will facilitate the identification of pollutant sources.