[NightWing]

Hi My Dear Foamers !!!

I recently started working with OpenFOAM and Many of stuffs i am confused about OF. Everyday i am learning useful things in OF bcoz of CFD online and its discussions. Foremost thank you all for the great help!


Recently, I am trying to workout an incompressible flow through a pipe. I have chosen, buoyantBoussinesqPimpleFoam as my base solver. I wanted to study a transient case and laminar, so i have taken out the turbulence part from the solver and modified it. However, I want to apply the boundary condition on the pipe wall as a uniform heat flux boundary condition. Foremost, as i dig up the user guide and cfd forums i found that we could use fixedGradient patch to specify heat flux condition on wall.


TubeWall
{
type fixedGradient;
gradient uniform ________; <--- we can input a value
}

As far as my understanding about the physics. I am modeling only the fluid domain, so the heat flux which i want to apply say it is 100 W/m2. So if my fluid is water,
gradient = Q"/k where k is for the fluid.

Is this correct way to specify the fixedGradient Boundary Condition???

If am wrong please do Correct me????

Thank you FOAM-Ers in advace !!!! Have a Great Day@@@

[dewey]

Hi

I am trying to do a pipe with air and heat flux in the wall, did you find how to do, something like that? how can i put heat flux on wall?

[nikitin-pro]

Unfortunately it's not so simple. FixedGradient BC for temperature will simply ensure a prescribed delta T between wall and fluid.
Here you are dealing with solid-fluid interface, where conductivity changes. So you have to implement Fourier law:
q = k*dT, where k -- heat transfer coefficient [W/m2*K].