[Rajaero]

Can somebody explain the procedure to set the boundary condition to find out convection heat transfer coefficient (h) in fluent?

In my case i have solid body surrounded by Fluid domain. i need to findout convection heat transfer rate and h value. I already tried to find out the h value but i want to make sure that Fluent calculates the correct value of h.

Thanks in Advance....

[yow]

Make sure that the solid and fluid domain are NOT under the same part before meshing. Then, Fluent will generate two surfaces at the fluid/solid interface, one for the fluid, one for the solid. You should be able to use the coupled boundary condition at those two surfaces; Fluent will automatically calculate heat transfer b/w the two without you needing to specify heat transfer rate.

To get rate, after simulation: Reports (under Results) > surface integrals > report type: integral > field variable: wall fluxes and surface HX coefficient. I've never tried it though.

Unfortunately, I'm having trouble with my interface too; my fixed temp fluid/solid simulation has a much thinner thermal boundary layer than just a fluid with one side at the same fixed temp. If you can help, I would appreciate it!

coupled walls vs constant wall T

Edit: nevermind, figured out why

[Rajaero]

hello,
thanks for your suggestion. in my simulation i have done everything you said. i got the h value also. but i want to know after we create the interface for solid and fluid, where we need to set the temperature for solid. bcz if i set the coupled interface i cant able to set the temperature value for the solid body right?
whether i need to use,
1.wall boundary condition with constant temperature and thickness
or
2.convection boundary condition with free stream temperature only (i dont have h value)

[Rajaero]

my suggestion for you,
1.i am wonder if you fixed you temperature there will not be any heat transfer bcz its already fixed. may be fluent will give you some temperature variation but i dont think its a good setup.
2. you can increase the wall thickness then you will get the thick boundary for the wall surface. you can see this option in wall boundary condition. its a conjugate heat transfer method.

if you have any suggestion about my case plz let me know..
thanks in advance

[yow]

Originally Posted by Rajaero

hello,
thanks for your suggestion. in my simulation i have done everything you said. i got the h value also. but i want to know after we create the interface for solid and fluid, where we need to set the temperature for solid. bcz if i set the coupled interface i cant able to set the temperature value for the solid body right?
whether i need to use,
1.wall boundary condition with constant temperature and thickness
or
2.convection boundary condition with free stream temperature only (i dont have h value)

Not sure if I understand what you're asking. If you want to force a temperature on the surface of the solid, you can exclude the solid and just use temperature condition at the wall. If you want to simulate the solid heating up or cooling down with known T_surface, you can either force temperature on both the fluid and solid surfaces that are touching or simulate the solid separately.

Coupled calculates temperatures for you (i.e. if you cook a pie in an oven and you know the air temperature in the oven but not the temperature at any place on/in the pie).

[Rajaero]

i understood and i am also doing the same method. i just wanna make sure.
thanks for your reply.