Hi,
If one body has 560 deg temparature, that body put in ambiant temparature 4 sec. Then What is body temparature after 4 sec (means temparature lose)?
How will do this process in thermal analysis? Please clarify us this problem.
Thanks,
Jagadeesh
Hi,
If one body has 560 deg temparature, that body put in ambiant temparature 4 sec. Then What is body temparature after 4 sec (means temparature lose)?
How will do this process in thermal analysis? Please clarify us this problem.
Thanks,
Jagadeesh
this assumes the heat loss is only from radiation. what about convection. but i agree, you could solve this problem by hand.
with the software, you're looking at a transient thermal analysis in simulation professional.
Yes Jared you are right, I will like to correct myself.
Total Heat Loss = Heat Loss due to Convection + Heat Loss due to Radiation.
Convection q (conv) = hA(Th - Tc)
where
q(conv) = heat transfer per unit time due to Convection (W)
h = heat transfer coeficient (W/m2K)
Th = hot body absolute temperature (K)
Tc = cold surroundings absolute temperature (K)
A = area exposed to environment of the emitting body (m2)
__________________
Radiation q (rad) = ε σ (Th4 - Tc4)A
where
q(rad) = heat transfer due to Radiation per unit time (W)
ε = emissivity of the object (one for a black body)
σ = 5.6703 10-8 (W/m2K4) - The Stefan-Boltzmann Constant
_________________
Total Heat Loss = q(conv) + q(rad)
Just multiply above retrived Total Heat Transfer by 4 (as the body is kept for 4 seconds in environment), you will get total heat loss to environment.
i.e.
Loss to environment = Heat transfer per unit time X Time
Divide Total Heat Loss to Environment with specific heat of body
i.e. Temperature drop (or Temperature difference) = Heat loss / Specific Heat of body
So ultimate temperature of body will be equal to 560 - Temperature Drop.
Thanks
Jagadeesh,
In addition to what Sandip and Jared said, the body will not have a single temperature. The skin will be cooler than the interior.
Jerry S.
Dear Jagadeesh,
If you dont mind, will like to ask you, why you want to make an analysis, cause it can be done through a simple calculations as below
q = ε σ (Th4 - Tc4)A
where
q = heat transfer per unit time (W)
ε = emissivity of the object (one for a black body)
σ = 5.6703 10-8 (W/m2K4) - The Stefan-Boltzmann Constant
Th = hot body absolute temperature (K)
Tc = cold surroundings absolute temperature (K)
A = area exposed to environment of the emitting body (m2)
Just multiply above retrived q by 4 (as the body is kept for 4 seconds in environment), you will get total heat loss to environment.
i.e.
Loss to environment = Heat transfer per unit time X Time
Once you recieve total loss to environment, again divide it with specific heat of body
i.e. Temperature drop (or Temperature difference) = Heat loss / Specific Heat of body
So ultimate temperature of body will be equal to 560 - Temperature Drop.
Hope this will help you.
Thanks
Sandip Darveshi.