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Details

Fundamental Investigation of Exhaust Hoods.

PB91173393

Publication Date	1990
Personal Author	Esmen, N. A.; Weyel, D. A.; Grauel, T. A.; Ilori, A. G.; Jossell, S.
Page Count	132
Abstract	The study investigated the theoretical aspects of airflow in front of freely suspended flanged hoods with arbitrarily, but symmetrically shaped hood orifices. Results indicated that an extension of the superimposition of two virtual sinks and potential flow assumption to describe the flow field can be used. The observed effect of turbulence on the capture efficiency of hoods and the magnitude of the reduction of the capture efficiency with what might be considered to be a relatively mild turbulent cross draft. Experimental data indicated that a turbulent cross draft in the order of 5 to 10% of the hood induced air speed in the mean velocity magnitude can reduce the overall capture efficiency of a hood by 15%. Using a conformal mapping technique, the theoretical investigations were also extended to include hoods with adjacent planes of arbitrary orientation. Optimization techniques which consider the hood geometry were investigated. The identified technique can be used to select hood orifice shape and dimensions not only to achieve proper control but also improve the mechanical efficiency of the process.
Keywords	Exhaust hoods Occupational safety and health Environmental surveys Inudstrial hygiene Indoor air pollution Ventilation Air flow Air pollution control Performance evaluation Design criteria Comparison
Source Agency	National Institute for Occupational Safety and Health
NTIS Subject Category	68G - Environmental Health & Safety 68A - Air Pollution & Control 57U - Public Health & Industrial Medicine 94D - Job Environment
Corporate Authors	Pittsburgh Univ., PA. Dept. of Industrial Environmental Health Sciences.; National Inst. for Occupational Safety and Health, Cincinnati, OH.
Supplemental Notes	Sponsored by National Inst. for Occupational Safety and Health, Cincinnati, OH.
Document Type	Technical Report
Title Note	Final rept.
NTIS Issue Number	199114

Fundamental Investigation of Exhaust Hoods.

Fundamental Investigation of Exhaust Hoods.
PB91173393

Publication Date	1990
Personal Author	Esmen, N. A.; Weyel, D. A.; Grauel, T. A.; Ilori, A. G.; Jossell, S.
Page Count	132
Abstract	The study investigated the theoretical aspects of airflow in front of freely suspended flanged hoods with arbitrarily, but symmetrically shaped hood orifices. Results indicated that an extension of the superimposition of two virtual sinks and potential flow assumption to describe the flow field can be used. The observed effect of turbulence on the capture efficiency of hoods and the magnitude of the reduction of the capture efficiency with what might be considered to be a relatively mild turbulent cross draft. Experimental data indicated that a turbulent cross draft in the order of 5 to 10% of the hood induced air speed in the mean velocity magnitude can reduce the overall capture efficiency of a hood by 15%. Using a conformal mapping technique, the theoretical investigations were also extended to include hoods with adjacent planes of arbitrary orientation. Optimization techniques which consider the hood geometry were investigated. The identified technique can be used to select hood orifice shape and dimensions not only to achieve proper control but also improve the mechanical efficiency of the process.
Keywords	Exhaust hoods Occupational safety and health Environmental surveys Inudstrial hygiene Indoor air pollution Ventilation Air flow Air pollution control Performance evaluation Design criteria Comparison
Source Agency	National Institute for Occupational Safety and Health
NTIS Subject Category	68G - Environmental Health & Safety 68A - Air Pollution & Control 57U - Public Health & Industrial Medicine 94D - Job Environment
Corporate Authors	Pittsburgh Univ., PA. Dept. of Industrial Environmental Health Sciences.; National Inst. for Occupational Safety and Health, Cincinnati, OH.
Supplemental Notes	Sponsored by National Inst. for Occupational Safety and Health, Cincinnati, OH.
Document Type	Technical Report
Title Note	Final rept.
NTIS Issue Number	199114