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Questions of the modelling of a light bulb using Heat Transfer Module
Posted Jan 29, 2013, 6:13 AM EST Heat Transfer & Phase Change, Computational Fluid Dynamics (CFD) Version 4.3 1 Reply
Now I am trying to carry out some simulations using heat transfer module. To start with, I downloaded the "free convection in a light bulb" model, which can be obtained from:
After investigated this model, I still have some questions and I will appreciate if can get your help.
1, for the tungsten filament, which is set as the heat source, its surface emissivity is set to be 1 (can be found in surface-to-surface radiation 2). Does that mean it is assumed to be an ideal blackbody radiation?
2. the tungsten is able to emit heat using surface-to-surface radiation, what is the relationship between surface-to-surface radiation and blackbody (or greybody) radiation?
3. From my understanding, the heat emitted by the heat source (tungsten) heats up the inner wall of glass envelope by both radiation and convection. The inner part of the wall will also radiate heat and that's why it is set to surface-to-surface radiation as well (its surface emissivity is set to be 0.8). Is this understanding correct?
4. The glass is set to opaque, does that mean there is no heat radiation can go through the glass from its inner wall to its outer wall? If so, how could the temperature of the outer wall increase, e.g. by conduction?
5. After this process, the outer wall of the glass envelope is heated up. The final temperature of the outer wall can be obtained by considering surface-to-ambient radiation as well as convective cooling. Is this correct?
Sorry for many questions which may stupid to you. But as a newbie of COMSOL, any help from you is highly appreciated. Many thanks in advance.