Direct flame impingement heating technology is widely used in the field of steel heat treatment processes and is currently fueled by natural gas. Hydrogen, as a clean energy source and its high laminar flame propagation speed, combined with natural gas will improve the fuel combustion speed and reduce the emission of carbon oxides and nitrogen oxides. In this paper, a numerical model of direct flame impingement heating of steel plate was established using Fluent, and the heat transfer characteristics of direct flame impingement heating of steel strip were investigated under different hydrogen doping, Reynolds number, and factorless distance conditions. The results show that the temperature and heat flow density of the steel plate of the heated target decrease with the increase of hydrogen doping from 0 to 25% at a heating time of 10 s. The temperature of the steel plate stationary point decreases from 385.36 K to 374.31 K, and the heat flow density of the steel plate stationary point decreases from 154 828 W/m² to 137 926 W/m². With the increase of Reynolds number from 13 400 to 33 600, the steel plate stationary temperature increased from 347.04 K to 450.90 K, the pressure increased from 14.93 Pa to 136.53 Pa, but the uniformity of the temperature and pressure of the steel plate deteriorated gradually. The increase of the causeless distance from 25 to 45 made the temperature of the steel plate stationary point decreased from 442.42 K to 344.36 K, and the pressure was reduced from 106.00 Pa to 24.81 Pa and the distribution was more inhomogeneous.

Aiming at the periodic characteristics of severe slug flow an experimental study was carried out through the downward?riser system. Based on the experimental data and the variation of pressure in the pipe, the variation rule of the severe slug flow period was analyzed and verified reciprocally with the calculation model results. It turned out that the flow state in the tube would change under different experimental parameters such as the inclination angle of the downdip tube, the gas phase conversion velocity or the liquid phase conversion velocity. The time of the slug eruption and slug reflux was basically changeless on account of the height of the riser was invariant, so the period of severe slugging depends on the time of slug formation and slug outflow stages. And it was mainly affected by the inclination angle of downward riser, gas superficial velocity or liquid superficial velocity.