Investigation on the storage performance of expanded volume exhaust hood for intermittent high-temperature smoke

In industrial production processes, intermittent high-temperature smoke with pulse emission is often generated. The use of an expanded volume exhaust hood (EVEH) could buffer the excess smoke during the peak stage. This study uses numerical simulation to investigate the storage mechanism and performance of the EVEH. The flow field characteristics and storage capacity rate corresponding to different exhaust flow rate to emission rate ratios, expansion methods, and hood volumes are analyzed. The results indicate that during the peak stage, the airflow impacts the inner side of the EVEH to form vortex, which could help EVEH to store excess smoke. The vertical expansion method is more conducive to the storage of smoke. For vertical EVEH, the maximum storage capacity rate does not change when the hood volume remains constant. A design method and applicable range for the storage of the EVEH has been proposed, which adapts to the emission of intermittent high-temperature smoke. The designed EVEH used this method has a capture efficiency of more than 90% and a maximum storage capacity rate of 30%. The results of this study could help design and use of EVEH in residential and industrial local ventilation.