Operating room ventilation with laminar air flow ceiling and a local laminar air flow system near the operating table for the patient

The aim of this study is to determine how the air flow from a unidirectional air flow (UAF) system and a local ventilation system will interact with each other. The study analyzes the air circulation near the operating table at different air flow velocities from both systems. The air flow velocities correspond to the usual range of velocities that are recommended by norms and guidelines. The research was approached by numerical and experimental studies. The thermal plume of the patient was measured by Particle Image Velocimetry (PIV) and thermography (IR) and compared with the results from the numerical case. A mesh independency study was made for the numerical case. The study showed that velocities ≥0.2 m/s from the UAF, depending on the height of the room, can overcome the thermal plume generated by a human subject with a moderate activity (100÷120W). The velocities from the local ventilation system need to be higher with at least one step, in accordance with the distance from the ventilation system to the operating wound, in order to avoid disturbances generated from the UAF system. (paper)