Finite difference methods for computation of flow into local exhaust hoods.
Am Ind Hyg Assoc J 1989 Oct; 50(10):526-534
A finite difference method was presented for computing the airflow into local exhaust hoods. This method was developed using the plain and flanged slot configurations. A theoretical definition was developed for a slot exhaust opening. Analytical models were developed for the slot and the flanged slot. A comparison of experimental and theoretical data for slot configurations was conducted. The study indicated that the assumption of potential flow closely approximated actual conditions of airflow into local exhaust hoods. This implied the applicability of Laplace's equation in terms of the velocity potential. The method was useful for solving problems in which the location and shape of the flow boundary and the values of the velocity potential or its normal derivatives were known. The method was also useful in solving flow problems in which it was possible to calculate the velocity potential in space from all line or point sinks comprising the hood. The availability of analytical models for the slot facilitated comparison with numerical results. Closed form analytical solutions are available for relatively few exhaust hood configurations. This finite difference method was successful in computing the flow into plain and flanged slots.
NIOSH-Author; Ventilation-equipment; Control-technology; Laboratory-equipment; Air-flow; Ventilation-hoods; Air-quality-control; Mathematical-models
American Industrial Hygiene Association Journal