Necessary conditions for flame combustion:
1、 Flammable substances. Any substance that can react violently with oxygen or other oxidants in the air is usually called flammable substance. For example: wood, paper, gasoline, alcohol, hydrogen, sodium, magnesium, etc.
2、 There are also some combustion-supporting substances. Any substance that can react with combustibles and cause combustion is called combustion-supporting substance. For example: air, oxygen, chlorine, sodium peroxide, etc.
There should be enough fire sources. Any thermal energy that can cause the combustion of combustibles is called an ignition source. For example: open fire, red body, Mars, focused heat, mechanical heat, lightning, heat, heat, electricity, etc.
Only when more than three kinds of combustion need to exist at the same time, the combustible will burn. However, under certain conditions, in addition to the three elements of combustion, the following conditions are also required:
First, there should be enough combustible materials. If the concentration of gas or steam in the air is insufficient, combustion will not occur. For example, using matches to light gasoline at normal temperature can burn immediately, while using matches to light diesel at normal temperature cannot burn.
2、 There should be enough inflammables. If there is not enough combustion-supporting agent to burn, the flame will gradually weaken until it is extinguished. It is like lighting a candle in a closed small space, gradually consuming oxygen, and finally going out.
3、 The igniter should reach a certain temperature and have enough heat energy. If Mars falls on cotton, it is easy to catch fire and fall on wood, but not easy to catch fire, because wood needs more heat than cotton. In summer, white phosphorus is easy to burn naturally, while coal is different, because the temperature required for white phosphorus combustion is lower (34oC), while coal requires higher combustion temperature (3652oC).