Mechanisms and Effects of Wall-Attachment Ventilation–thermal Plume Interaction on Airflow and Aerosol Control in Dental Clinics

Dental clinics are enclosed environments where patients generate significant quantities of aerosolized pathogens during procedures. Under low-velocity ventilation conditions, indoor airflow is strongly influenced by human thermal plumes, which hinder effective pollutant removal. This study combines numerical simulations with experimental validation to analyze the coupled effects of wall-attached jets and human thermal plumes on airflow and aerosol transport in a single-chair dental clinic. The air supply is provided through linear slot diffusers mounted on the ceiling with dimensions of 1.5 m & times; 0.05 m. The results show that, at low supply velocities, the ventilation jet and thermal plume interact, with optimal coupling occurring at a supply air velocity of 0.6 m/ s. Beyond this velocity, plume integrity deteriorates due to jet-induced disruption. Mechanistic analysis identifies the transition from buoyancy-dominated to jet-dominated flow between 0.6 and 0.8 m/s. At 0.6 m/s, a dynamic balance is achieved between jet momentum and thermal buoyancy, producing a maximum plume rise velocity of 0.24 m/s. When the supply air velocity exceeds 0.8 m/s, increased recirculation and plume fragmentation reduce the effectiveness of directional aerosol transport. To address higher ventilation requirements, the study further optimized vent configurations. One scenario was identified in which 68.75% of the clinician's breathing-height plane exhibits aerosol concentrations below 27% of the initial value, making it the most effective solution. The research results provide reference for optimizing ventilation design in dental clinics and propose practical strategies for controlling aerosol transmission pathways and reducing the risk of cross-infection.