Abstract: Fire smoke extraction is crucial for firefighting and rescue operations as well as for ensuring the safety of personnel on site. Hydraulic ventilation smoke extraction is a method that utilizes high-velocity water jets from fire nozzles to entrain and remove smoke. It offers advantages such as high flexibility and no need for additional equipment; however, systematic experimental research and theoretical support are currently lacking. This study focuses on hydraulic ventilation smoke extraction technology and employs a controlled variable method to investigate the effects of the distance from the nozzle to the window (ranging from 223 mm to 1 437 mm), spray angles (45° and 60°), and convection conditions on smoke extraction performance. A lux meter was used to monitor real-time changes in smoke concentration, enabling quantitative evaluation of smoke extraction efficiency. The results show that the highest smoke extraction efficiency is achieved when the nozzle is positioned 667 mm from the window, with the water jet diameter not exceeding the window area (i.e.,when the spray angle is 60°) . The experimental findings indicate that the nozzle-to-window distance, spray angle, and convection conditions are key factors influencing the effectiveness of hydraulic ventilation smoke extraction. Reasonable optimization of these parameters can significantly improve smoke extraction efficiency, providing theoretical support and practical guidance for smoke extraction in fire scenes.

Key words: hydraulic ventilation smoke extraction, smoke exhaust efficiency, water gun, smoke extraction methods