DEFINING THE HEAT TRANSFER PROBLEM
DEFINING THE HEAT TRANSFER PROBLEM
(OP)
HI ALL
I HAVE A TIRE CURING PRESS WITH UPPER AND LOWER HOUSING AND THE MOULD. (MOULD 90% IN UPPER HALF AND 10% IN LOWER HALF.THE MOULD IS HEATED AXIALLY BY TWO STEAM PLATENS AND ALSO RADIALLY BY JACKETS.THE MOULD IS SURROUNDED BY 2mm THICK ALUMINIUM SHEET AND THEN BY 40.5mm THICK GLASS WOOL. THE THICKNESS OF UPPER HOUSING IS 25mm.THE SURFACE TEMPERATURE OF MOULD IS AROUND 200 DEG AND AMBIENT AIR TEMP IS 30 DEG. THE MAX SURFACE TEMP ALLOWED AT UPPER HOUSING WAS 40 DEG.
I CONSIDERED THIS AS A STEADY STATE PROBLEM WITH NO INTERNAL HEAT GENERATION AS A COMPOSITE HOLLOW CYLINDER PROBLEM.
I FOUND THAT THE SURFACE TEMP WAS WELL BELOW 40 DEG (37-38 DEG)
BUT IN REALITY THE SURFACE TEMPERATURE IS 65 DEG.
HAVE I DEFINED THE PROBLEM WRONGLY ?, OR ARE MY INPUTS WRONG ?
WHAT ELSE SHOULD I CONSIDER
PLEASE DON'T TAKE ME WRONG AS I'M FRESH GRADUATE WORKING ONLY FOR A MONTH WITH NO ONE TO GUIDE ME.
I WILL EVENTUALLY LEARN . HELP ME TO GIVE A PUSH.
I HAVE A TIRE CURING PRESS WITH UPPER AND LOWER HOUSING AND THE MOULD. (MOULD 90% IN UPPER HALF AND 10% IN LOWER HALF.THE MOULD IS HEATED AXIALLY BY TWO STEAM PLATENS AND ALSO RADIALLY BY JACKETS.THE MOULD IS SURROUNDED BY 2mm THICK ALUMINIUM SHEET AND THEN BY 40.5mm THICK GLASS WOOL. THE THICKNESS OF UPPER HOUSING IS 25mm.THE SURFACE TEMPERATURE OF MOULD IS AROUND 200 DEG AND AMBIENT AIR TEMP IS 30 DEG. THE MAX SURFACE TEMP ALLOWED AT UPPER HOUSING WAS 40 DEG.
I CONSIDERED THIS AS A STEADY STATE PROBLEM WITH NO INTERNAL HEAT GENERATION AS A COMPOSITE HOLLOW CYLINDER PROBLEM.
I FOUND THAT THE SURFACE TEMP WAS WELL BELOW 40 DEG (37-38 DEG)
BUT IN REALITY THE SURFACE TEMPERATURE IS 65 DEG.
HAVE I DEFINED THE PROBLEM WRONGLY ?, OR ARE MY INPUTS WRONG ?
WHAT ELSE SHOULD I CONSIDER
PLEASE DON'T TAKE ME WRONG AS I'M FRESH GRADUATE WORKING ONLY FOR A MONTH WITH NO ONE TO GUIDE ME.
I WILL EVENTUALLY LEARN . HELP ME TO GIVE A PUSH.





RE: DEFINING THE HEAT TRANSFER PROBLEM
Nobody's going to help you try to do anything that does not have a well described problem and a clear question or two.
"People will work for you with blood and sweat and tears if they work for what they believe in......" - Simon Sinek
RE: DEFINING THE HEAT TRANSFER PROBLEM
> What's the intent of the exercise? Do you need exact matches, or are qualitative behaviors good enough?
> What was the pedigree of your inputs? Measured? Guessed? Datasheet?
Odd geometries are not amenable to simple calculations. Heat transfer problems are rife with "correlations" which is a polite term for fudge factors that allow you to "correlate" your calculated answer to the measured answer.
TTFN
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RE: DEFINING THE HEAT TRANSFER PROBLEM
So the assumption of no internal heat generation jumps out immediately as being wrong.
RE: DEFINING THE HEAT TRANSFER PROBLEM
Thanks for the reply.This is my first post in first forum.You stated that i poorly described the problem.Can you please help me in stating the problem?.What should i provide (drawings,assumptions) etc.I'm new so please guide me.
Thanks in advance
RE: DEFINING THE HEAT TRANSFER PROBLEM
TTFN
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RE: DEFINING THE HEAT TRANSFER PROBLEM
These are the inputs that i could get from my superiors.
Please help me
Thanks in advance
RE: DEFINING THE HEAT TRANSFER PROBLEM
It is impossible to lower the ambient temperature by placing a hot thing in the space, yet that is what your PDF is asking for.
Once again, your assumption of no internal heat generation is incorrect.
It's a heat transfer problem, so you are going to need some values that include heat. Temperature is not heat.
RE: DEFINING THE HEAT TRANSFER PROBLEM
You should also read forum policies:
>>>>>>These fora should not be used to bypass your own in-depth research on the issues that affect you, nor is it intended to >>>>>>>be a substitute for appropriate professional assistance within your field or geographical region.
You need to hire an Engineer who can at least understand the problem and formulate a question.
RE: DEFINING THE HEAT TRANSFER PROBLEM
TTFN
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