Abstract
The feasibility of a jet augmented local exhaust system to control air contaminants was investigated in a scale model hood. Tracer gas concentrations were mapped on top of idealized airflow streamlines to illustrate the jet's interaction with air contaminants. A key finding was the possibility of contaminant loss from the hood if the jet flow was not recaptured completely. Airflow design parameters, which had been identified previously to affect the airflow pattern, were evaluated for their effect on air contaminant control. The results indicated that tracer gas recovery was affected by a single airflow design parameter. An inverse linear relationship between the design parameter and control levels indicated that the recovery rate was controllable in design and that 100% control was achievable at a low total airflow rate. Important potential design advantages include the ability to specify the,contaminant control level prior to installation, system flexibility to change contaminant control levels by adjusting airflow design parameters, and lower installation and operation costs than a comparable local exhaust system. The next research step is to test a full-scale prototype system to evaluate its performance efficiency and economy under realistic operating conditions.