heat transfer simulation in oven

[Amine A]

hello, we bake aeronautical pieces in an oven.
the piece ( prepreg + nomex ) being in the mold, we put it inside the oven.
a thermocouple is linked to the surface of the mold.
a temperature profile is applied to the oven chamber (ramp up, holding, ramp down).
I want to make a thermal simulation which allows me to know what is the temperature profile given by the thermocouple.
can I do that in Abaqus ? if yes what are the general steps to do it ?
Thanks

 

[Amine A]

I know that the type of the heat transfer convection ( forced or natural ) will affect only the film coefficient . So can it be a problem , for such simulation, to enter directly the value of the coefficient h and do not modelling the convection ( natural or forced ) ?

 

[FEA way]

Regular heat transfer analysis will be significantly less accurate than CFD since you have to assume approximate film coefficient and it can’t account for changes within the fluid or model the natural convection. CFD will also let you include more radiation factors. However, regular heat transfer analysis is often chosen for simplicity. In many cases this type of simulation is sufficient.

 

[IceBreakerSours]

Agree wholeheartedly with FEA way. As a modeler/analyst, you are (numerically) solving an approximate model of the underlying physics. The number of items, their distribution, etc. may be of ultimate interest but, before you worry about the technical details, the most essential physics must be solved first and correctly. If anything, I would learn more about the details of the oven (geometry, conducting/insulating/reflecting parts, location of the heating elements, are there any fans?, etc.). If there are fans, you have may have significant convection effects to consider. If you go down that rabbit hole, do you need to consider boundary layer effects? It can get out of hand pretty quickly. This is why I recommend talking to an expert in the field - an authority figure, preferably.

To answer your question in the previous post, whether ignoring an effect or incorporating an effect depends on what the ultimate purpose is, what you have to work with, what limitations you have, so on and so forth.

As an analogy (thanks, in part to, Covid-19), if I were to make a fancy meal and feed it to a toddler, it wouldn't make much sense to spend hours and a hundred bucks to make it only to realize the toddler can't tell the difference between what is on the floor vs what is on the fancy plate. Terrible analogy, I know but I hope there is some point in there somewhere.

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[Amine A]

Thanks to both of you.
I agree with you and that is one of my problems really. In fact, I don't know what are the variables to be considered important (knowing that the figure of the oven in below) .I am doing this work by my own, if you have any ideas I would be thankful.

 

[Amine A]

FEA way , I hope you are doing good.
I put a model in comsol . I applied a heat flux on the wall of the oven and I put the "Text" as the variable temperature ( temperature profile) and I added a fan .
after computing , I find that the temperature on the surface of the piece is constant which is not logic (it's like there is no interaction between air and piece or the air is not a good conductor of heat ) or it may be another problem : maybe I shouldn't put a variable heat flux or temperature profile on the wall..maybe I should put a source of heat and I find difficulties to do this because the heat is Q = h ( T - Text ) and the data that I have is a temperature profile ..
Anyways , I didn't know what to put in boundary to solve it
thanks in advance for your help brother