图为不同粒径粒子的温度与轴向距离的关系图，实线表示2 MPa二次注氮压力下的焰流温度变化，点线表示不同粒径的粒子温度变化。如图所示，粒子在喷枪直管段内部升温较快，而在空气域中的自由射流区升温趋势相对缓和，且所有粒子在距离喷口约0.163 m处均能达到粒子的最高温度。受高温焰流的影响，粒子的温度保持性较好，射出后基本贴近于温度峰值。

The graph shows the temperature versus axial distance for particles of different particle sizes, with the solid line indicating the flame temperature variation at 2 MPa secondary nitrogen injection pressure and the dotted line indicating the particle temperature variation for different particle sizes. As shown in the figure, the particles warmed up faster inside the straight section of the gun, while the warming trend in the free jet region in the air domain was relatively moderate, and all particles could reach the maximum particle temperature at about 0.163 m from the nozzle. The temperature retention of the particles is good due to the high-temperature flame flow, which is basically close to the peak temperature after injection.