[patilsachin]

Hello,

I am simulating an unsteady cooling/quenching process.
I have an solid object at 1000K and the surrounding fluid domain at Room temperature.

I have created interfaces to do a CHT analysis.

The models for Fluid are : 3D, Liquid, Constant Density, Segregated Flow, Segregated Fluid Temperature, Laminar, Gradients, Implicit Unsteady

The models for solid are : 3D, Solid, Segregated Energy, Implicit Unsteady

The stopping criteria are : Internal Iterations : 12 ; Max. No. of Steps : 1000 ; Maximum Physical Time : 200s

When I run the simulation, I am observing no temperature change (distribution) across the CHT interface and domain

Am I missing anything? Kindly help

[ashokac7]

Check your interfaces. Try to make automated contacts for interfaces. Use larger number of inner iterations at first.

Sent from my Redmi Note 3 using CFD Online Forum mobile app

[patilsachin]

Thank Your for your reply.

The Interfaces have been set as contact interface yet I don't get any kind of distribution of temperature across the the domain

[ashokac7]

Can't tell exact problem from here. May be there is some problem with set up. Or may be if flow velocity is more then very less time is available for heat to transfer across interface. But it should show some gradient after some time atleast. How much physical time have you ran your simulation.?

[patilsachin]

Thank You for the reply.

I understand the problem. I was running the simulation for too less of a time. Hardly few seconds.

But now I have encountered a new problem. The temperature drop is too less compared to experimental data. I am getting a drop of 100 degrees in 120 seconds while actual data shows a drop of around 500 degrees.

Any reason why that might be happening?

[ashokac7]

Have you tried steady case first.. That really helps in understanding the problem.. There may be a problem with meshing, or boundary condition, or material property. Try to run steady case first.

[patilsachin]

Thank you for your reply.

I have attached the attachments for steady and unsteady cases.

In case of steady case, the equilibrium is reached just after 20 iterations.

In case of Unsteady case, even after 2500 iterations ( 90 minutes), equilibrium is not reached.

[ashokac7]

Plz keep inner itarations more than 20 initially... Residual of any quantity should fall by order of e3 in same time step... If you are using same sim file then I don't think that there is problem with bc's or interfaces. Is results of steady case comparable with expt?