Figure 5 Temperature at various concentration of R123.
To further explore the effect of the addition of R123 on the flame, it is necessary to investigate the temperature change. Figure 5 shows the flame temperature at different heights changed over time. It is well known that both the heat-release rate per unit volume along the zone and the flame size affect the total quantity of heat[13, 30]. On the other hand, halogenated extinguishment added causes the flame reaction kernel weakened, which can decrease the heat of reaction. As shown in Figure 5, It can be clearly observed that R123 went from 0 to 4 %, and the temperature fluctuated in the range of 890 °C. Then the temperature of the spout and 5 cm height decreased as the addition exceeded 6 % until extinguishment, but the temperature of 10 cm, 15 cm and 20 cm height was increased, especially the 10 cm height increased from about 550 °C to about 750 °C. Therefore, it is speculated that the reaction kernel with the premixed flame structure was weakened and moved up by R123 addition, the temperature decreased, and the flame became unstable. At the same time, the addition of R123 would provide more reactants for the combustion of the trailing diffusion flame, thereby releasing additional heat and increasing the temperature at the tail flame.