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jeeva14
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how to reduce temperature of a solid bar from 550°c to 450°c by water spaying... someone really help me...??
Did you even think about the problem? That's not a very difficult problem to solve.jeeva14 said:a bar of d=120mm and l=200mm is heated to a temp of 550°c, then it has to be cooled to 450°c by water spraying. The amount of water sprayed need to be calculated and in how much time it would reach the desired temp is also to be find. Both ends of the bar is adiabatic, and the heat transfer is considered over the circumference. I have clearly defined my problem. Now can u help me...?
caldweab said:Did you even think about the problem? That's not a very difficult problem to solve.
AlephZero said:Actually, it's an impossible problem to solve without making some drastic assumptions about how the water spray interacts with the bar.
If you make some highly unrealistic assumptions, you could turn it into a textbook type of problem. But without knowing more about the book, or what the OP's level of knowledge is, that is just guessing IMO.
jeeva14 said:a bar of d=120mm and l=200mm is heated to a temp of 550°c, then it has to be cooled to 450°c by water spraying. The amount of water sprayed need to be calculated and in how much time it would reach the desired temp is also to be find. Both ends of the bar is adiabatic, and the heat transfer is considered over the circumference. I have clearly defined my problem. Now can u help me...?
dawin said:Well now I feel like I'm missing something.
AlephZero said:To get you started thinking about what you are missing, how fast is the water being sprayed? Both interpretation of "fast" are relevant: liters/second and meters/second.
In real life, the water won't just sit on the bar until it boils.
It looks like one of the problems I solved in my heat transfer class. You do have to make some assumptions. I actually think I still have the assignment somewhere. I don't think he wrote the problem here as it is in the book though. Looks like he is just trying to get something to turn in.AlephZero said:Actually, it's an impossible problem to solve without making some drastic assumptions about how the water spray interacts with the bar.
If you make some highly unrealistic assumptions, you could turn it into a textbook type of problem. But without knowing more about the book, or what the OP's level of knowledge is, that is just guessing IMO.
Heat transfer in a solid bar occurs through the process of conduction, where heat energy is transferred from one molecule to another through direct contact.
There are several ways to reduce the temperature of a solid bar, including increasing the surface area, using insulation materials, and using a cooling system such as a fan or liquid coolant.
Increasing the surface area of a solid bar allows for more heat to be dissipated, as there is more area for the heat to transfer to the surrounding environment.
Materials such as foam, fiberglass, and ceramic are effective in reducing the temperature of a solid bar as they have low thermal conductivity and can prevent heat from escaping the bar.
Yes, a liquid coolant such as water or antifreeze can be circulated around the solid bar to absorb heat and carry it away, effectively reducing the temperature of the bar.