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Calculate heat transfer coefficient
Posted 03.06.2021, 09:37 GMT-4 Fluid & Heat, Computational Fluid Dynamics (CFD), Heat Transfer Version 5.6 0 Replies
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I want to model air flow past a helical coil with heat transfer, and I need to characterise the local heat transfer coefficient between the heated coil and the flowing air.
I cannot use a known relation since the geometry is complicated, so I need to find the resulting flux and then calculate h from flux = hA(T-Tinf).
However, if I find convective heat flux at a surface (ht.cfluxMag) (Results>Export>Data>Dataset:surface) , that seems to be the flux in the air medium rather than through the solid-air boundary, since it depends on the wind speed at the surface. I need the flux across the surface.
From www.comsol.com/blogs/calculating-the-heat-transfer-coefficient-for-flat-and-corrugated-plates/ it says "From the simulation results, it is possible to evaluate the heat flux using the corresponding predefined postprocessing variable." but it is not clear which predefined postprocessing variable they are referring to, since it is not ht.cfluxMag.
Is there a built-in function to calculate the flux through a boundary, or do I have to calculate it from other variables (eg. temperature at first grid node near boundary)?
I aim to set boundary condition at the coil of constant temperature and solve for the flux due to the air flow.
Tl;dr: How to find heat transfer coefficient by calculating heat flux through a boundary
Hello XQ Sun
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