Effects of medical staff's turning movement on dispersion of airborne particles under large air supply diffuser during operative surgeries

The present study examines the effect of medical staff's turning movements on particle concentration in the surgical zone and settlement on the patient under single large diffuser (SLD) ventilation. A computational domain representing the operating room (OR) was constructed using computer-aided design (CAD) software. The airflow and particle models were validated against the published data before conducting the case studies. The airflow in the OR was simulated using an RNG k-ε turbulence model, while the dispersion of the particles was simulated using a discrete phase model based on the Lagrangian approach. A user-defined function (UDF) code was written and compiled in the simulation software to describe the medical staff member's turning movements. In this study, three cases were examined: baseline, SLD 1, and SLD 2, with the air supply areas of 4.3 m2, 5.7 m2, and 15.9 m2, respectively. Results show that SLD ventilations in an OR can reduce the number of dispersed particles in the surgical zone. The particles that settled on the patient were reduced by 41% and 39% when using the SLD 1 and SLD 2 ventilations, respectively. The use of the larger air supply area of SLD 2 ventilation in the present study does not significantly reduce the particles that settle on a patient. Likewise, the use of SLD 2 ventilation may increase operating and maintenance costs.