FLOW REGIMES AND THERMAL PATTERNS IN AIR-CONDITIONED OPERATING THEATERS

Abstract

Airflow characteristics in the air-conditioned surgical operating theatres play an important role to obtain comfort and hygienic conditions for room occupants. The aim of this work is to investigate the flow regimes and air temperature distribution in• surgical operating theaters to reach a better design leading to improved comfort with the optimal indoor air quality (IAQ). This thesis utilizes a full 3D commercial Computational Fluid Dynamics (CFD) program called FLUENT.6 to assess the airflow characteristics in surgical operating theaters. The CFD modeling techniques solved the continuity, momentum, and energy equations when using k-e model for turbulence modeling in the Navier-Stokes equations. Also, Large Eddy Simulation (LES) is used in the• thesis briefly to model turbulence. The SIMPLE algorithm is used as equations solver. Grid sizes used in the present work exceeded 500,000 grid nodes in some cases, which adequately allow better and meaningful predictions of the flow regimes. Validation of the procedure is done by comparing results from FLUENT.6 to results from 3DHVAC (CFD code) and work of others. Predictions are obtained with both 0 codes, and good agreement is found among them and the available experimentation. • The present work answers several questions regarding room airflow motion prediction techniques such as the effects of turbulence model, grid node generation; thermal interactions, and numerical schemes. The present work concludes notable considerations that should be followed to obtain efficient air flow regimes in surgical operating theatres. It is found that the location of the air extract port represents a critical design factor and would have a direct effect on the air velocity and. temperature distribution. The most appropriate location for the air extract ports is that to be on all four walls of the room with two ports on the center of each wall one near the floor and the other near the ceiling when the air supply port is in the center of the ceiling.