Parking this (something I just read) here as I think it was this thread that flame propagation was discussed.
We think of combustion as a ball of flame in the combustion chamber - or that at least is how it is presented in video animations. In truth what goes on in there is the flame progressing spherically from the spark plug with the products of combustion behind it and the as yet unburned mixture ahead of it. Two distinct zones (like a balloon within a balloon) separated by the flame front. So far so obvious. What blew me away though is the thickness of the flame. 0.2mm, 0.008''. It's barely there! What a delicate thing it is that creates so much power.
We think of combustion as a ball of flame in the combustion chamber - or that at least is how it is presented in video animations. In truth what goes on in there is the flame progressing spherically from the spark plug with the products of combustion behind it and the as yet unburned mixture ahead of it. Two distinct zones (like a balloon within a balloon) separated by the flame front. So far so obvious. What blew me away though is the thickness of the flame. 0.2mm, 0.008''. It's barely there! What a delicate thing it is that creates so much power.