Prediction of bioparticles dispersion and distribution in a hospital isolation room

Abstract

Removal of bioparticles from hospital isolation room is important in reducing the transmission risk of infectious diseases. An effective ventilation system is necessary to protect the patient, doctor and nurses from catching infectious diseases. The goal of this study was to select the most effective ventilation scenario for the investigated isolation room among the defined scenarios. To select the most effective ventilation scenario, the effect of air exchange rate (ACH), injection angle (Ɵ) and exhaust position on removing the exhaled bioparticles from a patient mouth during coughing process, was investigated. Computational Fluid Dynamic (CFD) was used for predicting the air flow pattern and bioparticle transmission. Bioparticle dispersion and deposition was modelled by an Eulerian-Lagrangian approach. The mathematical model for air flow was the Reynold Averaged Navier Stokes (RANS) equations with k-ɛ turbulence model. Code-Saturne was chosen as the CFD program and validated by numerical results and empirical equations. The numerical results obtained by Code-Saturne were compared to results publish in the literature. To investigate the Code-Saturne capability to predict particle deposition, particles with different diameter in the range of 1 μm to 10 μm, were injected in a channel. Non dimensional deposition velocity obtained using Code-Saturne was compared to the empirical results available in the literature. The results showed that Code-Saturne has the capability of predicting the air flow pattern, particle dispersion and particle deposition. For analyzing the results and choosing the most effective ventilation system, particle removal efficiency (PRE) and normalized particle concentration in the inhalation zone were compared. Among the six ventilation scenarios with different ACH and Ɵ, scenario with ACH=15 and Ɵ=45° was selected as the most effective. Finally, effect of exhaust position was investigated. Three scenarios were defined. The first one with an exhaust mounted on a wall near the ceiling, the second one with an exhaust mounted on a wall near the floor and the last one with an exhaust mounted on the ceiling. It is observed that the exhaust position has great influence on the air flow pattern and particle removal. It is found that an exhaust mounted on the ceiling scenario has the best particle removal efficiency.

Date	9 Feb 2016
Original language	American English
Awarding Institution	École de technologie supérieure
Supervisor	Stéphane Hallé (Supervisor) & François Morency (Co-supervisor)