Improving Fire Suppression Efficiency in Electric Vehicles: A Study on Optimized Upward Spray Devices

Fire accidents in electric vehicles are mainly caused by battery fires, and one of the most effective fire suppression methods is to spray water from the bottom of a vehicle in an upward direction. In this study, analyses and experiments were conducted to improve the spray angle of a fluidic oscillator used for attaching an upward spray device. Through these analyses, the factors resulting in the maximum spray angle were derived from the four design variables of the fluidic oscillator, which were reconstructed for further analysis. The model that combined the radius of the mixing chamber curvature, inlet wedge width, and outlet wedge width exhibited the largest spray angle (84°) among the combination models that included the outlet wedge width variable. To evaluate the fire suppression performance of the fluidic oscillator nozzle, a cooling-rate comparison experiment was conducted with a recently used orifice nozzle. The results showed that the fluidic oscillator nozzle leads to a faster overall cooling rate than the orifice nozzle, rendering it more suitable for suppressing battery fires. After the production of the upward spray device, practical tests showed that it could spray a large area under a vehicle, thereby suggesting its applicability in actual fire scenes.