The burnout effect on boiling

The burnout phenomenon in boiling can be expressed like this
Before that please read 

In the Nucleate boiling region we saw the critical heat flux or the maximum heat flux. And we want more heat transfer and thus we have to heat the liquid further. But due to the some vapor covering the liquid cannot receive that heat as result the heater surface has to absorb the heat. This increase energy with increased excess temperature is absorbed by the heater surface. And further increase in the surface temperature causes the surface to leave that heat. It cannot take any more heat. But most of the time the heater surface cannot come to the position to leave it. Before that it melts. This is called burnout phenomenon. That’s why critical heat flux is called burnout heat flux. Most of the boiling heat transfer heaters are operated below the burnout heat flux to avoid that disastrous effect. High melting point metals can solve this problem. But in case of cryogenic application the burnout is not a problem. 

The burnout phenomenon

the boiling curve for water

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