Combustion, or burning, is a chemical reaction that requires three things: fuel, heat, and an oxidizer. The oxidizer in most cases is oxygen (O2), which reacts with the fuel to produce energy in the form of heat and light.
The amount of oxygen required for combustion depends on several factors, including the type of fuel being burned, the temperature at which it is burning, and the pressure under which the reaction occurs. However, as a general rule, the minimum concentration of oxygen needed to support combustion is around 16% by volume.
At this concentration, there is enough oxygen present to react with the fuel and provide the necessary energy to sustain the combustion process. If the concentration of oxygen falls below this threshold, the reaction will become sluggish, and eventually, it will cease altogether.
It's important to note that while 16% is the minimum concentration of oxygen needed to support combustion, it may not be sufficient for efficient combustion. For example, if the concentration of oxygen is too low, the flame may not be hot enough to ignite certain types of fuels, or it may burn sluggishly and inefficiently.
In some applications, such as in internal combustion engines, the air-fuel mixture must contain a higher concentration of oxygen than the minimum needed to support combustion. This is because the engine needs to generate a lot of power quickly, and having more oxygen available allows the fuel to burn faster and more completely, resulting in greater efficiency and performance.
Overall, the minimum oxygen level needed to sustain combustion is about 16% by volume. However, depending on the specific application, a higher concentration of oxygen may be necessary to ensure optimal combustion efficiency and performance.