Abstract: In order to study the horizontal jet flame morphology under multiple boundary constraints, a gas jet combustion experiment was conducted, with a jet rate of 1.04~6.25 m/s and a distance between the jet hole and the obstacle of 0.05, 0.10, 0.15, and 0.20 m. The flame diffusion behavior under different working conditions was studied, and the flame height was obtained based on image processing technology. The influence of jet rate and hole plate spacing on the characteristics of restricted horizontal jet flames was analyzed. The results show that as the injection rate increases and the hole plate spacing increases, the flame height decreases; When the injection rate is small and the hole plate spacing is large, flame diffusion is mainly controlled by buoyancy, and the flame does not fill the entire transverse area of the confined space. When the injection rate is high and the distance between holes and plates is small, the flame impacts the wall and spreads up and down along the impact point, resulting in a higher flame extension height. Establish a dimensionless prediction expression for flame height using non dimensional parameters such as coupled jet rate, hole plate spacing, and fire source power, making it suitable for calculating the height of a three side restricted horizontal jet fire.

Key words: jet fire, restricted flames, flame height, spray rate, obstacles