Wall temperature
Wall temperature
(OP)
Hello all!
I am intrested to know how to calculate a wall temperature in a heat exchanger. Both temperatures on the different sides of the wall are known. Is it the mean temperature?
Thanks,
Mask
I am intrested to know how to calculate a wall temperature in a heat exchanger. Both temperatures on the different sides of the wall are known. Is it the mean temperature?
Thanks,
Mask





RE: Wall temperature
If the heat transfer coefficient on one side is much larger than the other and is clean (eg. condensing steam inside a coil in a water bath), then the metal temperature would be pretty close to the saturation steam temperature since the condensing steam heat transfer coefficient is much larger than the natural convective heat transfer coefficient from the coil to the water bath.
If you have a copy of the TEMA standards, I believe they go through this calculation.
RE: Wall temperature
h1.A.(T1-Tw1) = k.A/e.(Tw1-Tw2)= h2.A.(Tw2-T2)
Notation seems to be typical....
hence, being
Tw2= h1/h2*(T1-Tw1) + T2,
the expression for Tw1 can be found:
(e/k+1/h2).T1 + T2/h1
Tw1 = ---------------------------
1/h1 + 1/h2 + e/k
So, the wall temperature is higly dependent upon the relative heat transfer coefficient. Here, if the heat transfer coefficient for Side 2 is 100 (water) and 10 for Side 1 (Oil), the wall temperature will be closer to the side 2 Bulk temperature.
Regards