Suggestion of a New Water-Mist System with Ultrasonic Wave

A water-mist fire-suppression system suppresses fire through heat absorption during the evaporation of microdroplets (< 100 µm). Its performance is expected to improve owing to the suffocation effect of water vapor, given the high expansion rate of water. However, conventional systems have complex structures because high-pressure pumps are required to generate microdroplets. Therefore, we propose a water-mist system that uses ultrasonic waves to generate microdroplets. In addition, a scaled room corner test model is constructed to validate the fire-suppression performance of the proposed system. Experiments are conducted to analyze the fire-suppression performance and the effect of airtightness using this scaled model. The results can be used to propose assessment standards for fire-suppression performance and to establish fire scenarios for real-scale experiments. Obstruction of air supplied through the door increases the total fire and fire-suppression durations due to inadequate oxygen. Based on temperature distribution and fire-duration analyses, fire-suppression can be improved by applying ultrasonically generated water-mist. However, additional investigations are required to evaluate the effects of fire size, water-mist flow rate, and fuel mass loss.