Numerical simulation of laboratory fume hood airflow performance.

A three-dimensional computational fluid dynamics (CFD) analysis has been used to predict airflow patterns in laboratory fume hoods. The simulation includes bypass fume hood primary operational features including the top and bottom bypasses, front airfoils, and rear-slotted baffles. All results were validated experimentally, and the simulation was found to adequately predict fume hood airflow patterns. The results indicate that fume hood flow patterns are highly dependent on inlet flow boundary conditions so that the computation must include the near field room airflow. Additionally, the study included the effects on the fume hood airflow of sash height changes, an operator positioned outside the fume hood, and equipment within the main fume hood chamber. It was shown that for conditions of a fully open sash height, a person in front of the fume hood, and an object inside the fume hood, the fume hood experiences a loss of containment of the flow.