surface heat flux problem

[MNS747]

hi all
i am doing a thermal analysis on a spindle. spindle got bearings inside. i did some tests on the real machine and i got the temperatures on the spindle surface as 27C running the machine for 1 hour. ambient temp was 23.5C. i dont know the bearing temp because of no access to the bearings, niether i want to apply temperature BC on the bearings because i want a gradual increase with time in thermal graph.

now to replicate i am applying surface heat flux in Abaqus. i calculated surface heat flux using q=kdt/L which can calculate 1D heat flux and it is obtained to be a bit high. Another option to use is Q=mcpdt which can calculate Energy but Abaqus only allows to put surface, body or concentrated heat fluxes. As my model in 3D could any one knows
1) how surface heat flux would be calculated?.
2) Could Q=mcpdt be used for it?

I would be grateful if i get any answers to this
Regards

 

[corus]

If the heat flow is predominantly 1D then calculating kdt/dx at one surface will give you the heat flux. You'd obviously have to measure an internal temperature too to get the temperature gradient. Alternativly if you know the heat transfer coefficient then kdt/dx=h(Ts-Ta). The heat flux at one surface will be the same heat flux at the other for 1D heat flow. The expression for Q=mCpdt is for mass flow past a surface, if my memory is correct, which I don't think is applicable.

corus

 

[MNS747]

hi
thanks corus for your valuable suggestion. i first try to know what my internal temperautre is by some means.

Regards