study cooling of a air cooled cylinder (thermal analysis)

[IlConte94]

Good evening,
as from title I wanted to ask to simulate air cooling of a cylinder 50 cc air cooled, which ansys workbench environment should be used; I'll explain better.

-I saw this tutorial on youtube

where simulation is carried out in "steady state thermal" using the same solver "mechanical" of a structural fem: I replicated the tutorial using my cad .step model and although it achieves convergence the results are obviously not right (by hindering that I would better apply the condition to the inner temperature boundary in a more restricted area to simulate the candle instead of the entire cylinder shirt): setting an internal temperature of 200° I get outside on the 188° fins! cooling does not work... (Note: I set the convection parameters as shown on youtube; among other things also on youtube there are results incompatible with reality: from 200 to 184°!)
-I tried therefore to carry out the same simulation in "transient thermal", although the phenomenon is almost certainly almost-stationary and not transient: I get better results but exaggerated in the opposite direction: from 250° inside (changed slightly for test) you pass to 20° on the fins... Here too the solver is the mechanical.. .
-I thought maybe you should use the "fluid flow" that I tried to open and is totally different from the other environment. . .

What do you think? In theory it should be a thermal simulation so cfd (fluent) but I do not understand then what it is to serve steady state and transient thermal.. .
thanks in advance

 

[Stan9411]

I'm not expert on these things and I don't handle it at all.
but, relying on the memories of the university, I suppose that the stable-state thermal applies the celeberrima equation of heat, which is one of the most famous equations to the partial derivatives never formulated.
cfd analysis is fluid dynamics. I think they integrate the equations of ship-stokes (simplified, because the complete ones are still unresolvable) and apply numerical methods like that of the finished volumes. thermal behaviour is probably possible, but cfd is not thermal analysis.

eye to take these extraordinary software and throw yourself to do analysis without knowing the theory of numerical methods such as your name and surname..

 

[IlConte94]

I'm not expert on these things and I don't handle it at all.
but, relying on the memories of the university, I suppose that the stable-state thermal applies the celeberrima equation of heat, which is one of the most famous equations to the partial derivatives never formulated.
cfd analysis is fluid dynamics. I think they integrate the equations of ship-stokes (simplified, because the complete ones are still unresolvable) and apply numerical methods like that of the finished volumes. thermal behaviour is probably possible, but cfd is not thermal analysis.

eye to take these extraordinary software and throw yourself to do analysis without knowing the theory of numerical methods such as your name and surname..

Hello, first thanks to the answer! Unfortunately, as you say, I am more "expert" in the structural context than thermofluodynamic, but I thought that the cfd included thermal phenomena, hence confusion. I confess that, as you noticed, I went a little nose, but with the awareness, before starting, of a high probability of getting high results but in the meantime of taking hand with the software.
then analyzing the process the cooling of these motors by moped, this happens through "forced" air as the motor is covered by a plastic head and the air is moved in the head to cylinder and head from the flywheel (with wings) calettato on the motor shaft. clearly the air is taken from the outside therefore the movement of the medium, although the motor is covered, a little influence the cooling. Now I don't know if such a phenomenon can be reproduced with the only equation of heat or you have to consider the air flows coming on the cylinder (cfd and more complex equations)! what I would like to understand at the end is the temperature distribution in the cylinder as a result of air cooling and the heat flow from the inside to the outside. .