Impinging jet ventilation has sufficient supply momentum to overcome thermal buoyancy, with the potential to reduce cross-infection risk in winter. Using an Eulerian-Lagrangian approach validated by experiments, this study compared the exhaled particle dispersion in a two-bed hospital ward heated by impinging jet ventilation and mixing ventilation. Exhaled particles with ten different diameters were tracked under four typical air changes per hour. Particle concentration distribution and residence time were compared. A revised Wells-Riley model was used to calculate the airborne infection probability of coronavirus disease 2019, with the help of a custom field function in Fluent software. The results indicated that impinging jet ventilation increased the air velocity in the occupied zone compared with mixing ventilation. The higher air velocity facilitated the control and removal of fine and medium particles, resulting in lower indoor particle concentration and shorter residence time for 0.5 – 10 μm particles under impinging jet ventilation. With the same air changes per hour, the average infection probability of coronavirus disease 2019 at the breathing zone of susceptible individuals under mixing ventilation could be 1.3 to 12.8 times higher than that under impinging jet ventilation. Additionally, the local infection probability at the face of susceptible individuals was lower under impinging jet ventilation. This study showed that impinging jet ventilation can be implemented in hospital wards to reduce the cross-infection during winter.
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