LOCAL EXHAUST VENTILATION - A NUMERICAL AND EXPERIMENTAL-STUDY OF CAPTURE EFFICIENCY

Capture efficiency of a local exhaust system, e.g. a kitchen hood, sho uld include only contaminants being direct captured. In this study bas ic concepts of local exhaust capture efficiency are given, based on th e idea of an imaginary control box. A validated numerical model is use d for estimation of the capture efficiency. An experimental technique is introduced for field studies taking into account knowledge of flow patterns of air and contaminants obtained from smoke testing and conta minant concentrations.