If we have a mixture of combustible gas (let's say it's methane) and air, what is the physical explanation for having a upper concentration limit?
I found this document:
Lower and upper explosive limits
For example, methane has 5% and 15%. Let's say we have a 30% concentration of methane... There is still enough oxygen, so that some of the methane could burn.
There won't be any combustion at all, or there is some combustion, but no explosion?