Lower layer of coal stove: C+O2 = ignition = CO2.
2. Middle layer of coal furnace: C+CO2 = high temperature = 2CO
3. Upper layer of coal stove: 2CO+O2 = ignition = 2CO2.
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Combustion is an exothermic and luminous chemical reaction, and its reaction process is extremely complicated. The chain reaction of free radicals is the essence of combustion reaction, and light and heat are physical phenomena in the combustion process.
The rapid exothermic and luminescent oxidation reaction of combustible materials with oxygen or air takes place in the form of flame. The combustion of coal, oil and natural gas is the main source of heat energy in all sectors of the national economy.
Recently, the surge of energy demand and the rapid development of aerospace technology have promoted the combination of fluid mechanics, chemical reaction kinetics and heat and mass transfer, and made the combustion discipline develop by leaps and bounds. On the other hand, the development of fire prevention technology aimed at eliminating combustion has also promoted the study of combustion theory.
In the combustion process, momentum, heat and mass are transferred among fuel, oxygen and combustion products, forming a complex flame structure with multi-component concentration gradient and non-isothermal two-phase flow. These transfers in the flame are realized by laminar molecular transfer or turbulent micelle transfer, while the industrial combustion device is mainly turbulent micelle transfer.
It is an important content to study the combustion process from the perspective of fluid mechanics and explore the distribution law of velocity, concentration and temperature in the combustion chamber and their interaction. Because of the complexity of combustion process, experimental technology is the main means to discuss combustion engineering.
Computational combustion developed in recent years has made remarkable progress in the research and development of engineering problems such as flow field in combustion equipment, fuel ignition and combustion heat transfer process, flame stability and so on by establishing a physical model of combustion process and numerically solving differential equations such as momentum, energy and chemical reaction.