What factors does the lighting effect of a flame depend on? 20

There are many factors that affect the length of a flame. The main factors are: the combustion medium, the flame surface diffusion rate of different substances is different when burning, and there are many other factors that affect the flame surface diffusion speed after determining the medium.

Including the type of combustible gas, the temperature of the combustible gas itself, and the injection direction and injection speed of the combustible gas, according to the situation you provide, the combustible gas is air, if the air is preheated before entering the furnace and not preheated, the diffusion rate of the flame surface after combustion is completely different, and the flame height is also determined. Another important factor is the inclination of the orifice, such as the upward and horizontal combustion speed of the orifice, and the length of the flame is also different, which is also affected by gravity. In addition, there is a clear relationship between the pressure of the gas, and the flame length of the combustion will be very long when the pressure is high.

According to the above conditions, I think you can reduce the medium pressure or flow rate (if it is a premixed type, you also need to adjust the size of the air premixed valve), expand the diameter of the burner nozzle, and adjust the angle of the burner nozzle downward.

There is the rigidity of the workpiece; heating position; flame heat; Heating area and cooling method.

Flame luminescence comes from two mechanisms, one of which is radiative recombination. In general, radiative recombination comes from partially plasmized gases in the flame, and due to the low plasma density, the brightness of this luminescence mechanism is not high. However, if some salt is added to the flame, the radiant recombination luminescence intensity will be significantly increased, which is called the flame color reaction.

The other part is blackbody radiation, which comes from heated solid particles in the flame, where the incompletely burned carbon particles act as solid particles. Air plasma luminescence is mainly the blue emission spectrum of nitrogen, and if there are salts, it is the flame color of the corresponding metal ions. Blackbody radiation is predominantly reddish-yellow.

The gas stove will add air to the flame, and the combustion is very complete, and the fuel thermal efficiency is high, but the light efficiency is very low. Ordinary lighters rely on natural convection to supplement oxygen into the flame, so the internal flame burns incompletely, the density of carbon particles is high, and the light emitting is relatively strong. Generally speaking, the internal pressure of the windproof lighter is much higher than that of ordinary lighters, and the fuel forms a high-speed air flow at the nozzle, and is fully mixed with the air through the viscous effect and burns completely, producing fewer carbon particles and weaker luminescence.

Air plasma luminescence is mainly the blue emission spectrum of nitrogen, and if there are salts, it is the flame color of the corresponding metal ions. The blackbody radiation luminescence is mainly red and yellow, and the gas stove will add air to the flame, and the combustion is very complete, and the fuel thermal efficiency is high, but the light efficiency is very low. Ordinary lighters rely on natural convection to supplement oxygen into the flame, so the internal flame burns incompletely, the density of carbon particles is high, and the light emitting is relatively strong.

Generally speaking, the internal pressure of the windproof lighter is much higher than that of ordinary lighters, and the fuel forms a high-speed air flow at the nozzle, and is fully mixed with the air through the viscous effect and burns completely, producing fewer carbon particles and weaker luminescence.

According to the junior high school chemistry teacher, the flame is a gas that burns and emits light, and after learning about theoretical physics, the flame is a luminous plasma, and in terms of the luminescence mechanism, it is because the ground state electrons in the particles in the plasma are excited to a high-energy state by heat, and then release energy when they transition down to the ground state - this energy is emitted in the form of light, and it emits light. As for the flame colors of different colors, as LS said, the characteristic peaks of different metal elements are located differently, and there are also different colors with characteristics. Taking candles as an example, the first is the sublimation of the flame core, that is, the candle is sublimated into wax vapor by heat; The wax vapor is heated and decomposed into many small organic fragments in the center of the flame, such as -ch, etc., these small organic fragments react with oxygen, and emit blue light at this time, and the complete degree of their reaction with oxygen determines the amount of carbon black particles generated, which also determines the brightness of the outer flame.

The brightness of the flame is affected by two factors, the first is the carbon content of the burning substance, and the second is the amount of oxygen involved in the reaction. Generally speaking, the higher the carbon content of the burning substance, the greater the brightness of the flame when burning (generally speaking, combustibles with high carbon content such as candles and acetylene are commonly used as lighting materials, while combustibles with low carbon content such as ethanol and butane are used as heating fuels, which are determined by their carbon content. Combustibles with high carbon content are mostly converted into light energy when burned, and combustibles with low carbon content are mostly converted into heat energy when burned); The more oxygen, the lower the brightness of the flame when burning.

As for why, the brightness of the common substance combustion comes from the blackbody radiation that occurs when the carbon black particles are burned, and the above two factors are the factors that affect the amount of carbon particles generated in the combustion reaction.