knocking is natural phenomenon which occurs in ic engine. no scientist in the world is capable to clearly explain this phenomenon but the explain much part of them....
how it occurs... in petrol eng...
"knocking" or "pinking" is the phenomenon in which pressure wave of high altitude generated strikes wall of combustion chamber.pre. waves are generated because fuel attain self ignition temp. before flame front created by spark plug reaches to it.
THE MAIN FACTOR RESPONSIBLE IS PRE-IGNITION.
We need a material which has got lowest thermal conductance inside, which is in contact with the boiled water..so from inside first come silver paper, thermocol sawdust.
The materials shall be placed in increasing order of their convective heat
transfer coefficient viz thermocol, saw dust, and then steel, which has the
highest heat transfer coefficient.
Please tell me if i am wrong.