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Flow Sim help needed - thermal chamber simulation

Question asked by Keith Mulhern on Nov 12, 2020
Latest reply on Nov 12, 2020 by Bill McEachern

I'm attempting to recreate a thermal chamber that we use for testing electronic devices. 


Quick rundown of model setup:

- Chamber is fully modeled with 20"^3 plenum with 250CFM convective fan at the rear.

- Fan is modeled as an internal fan with an inlet aperture at the top of the chamber and outlet at the bottom (which successfully represents the convective flow).

- Fluid subdomain set as 55C to represent ambient temperature.

- Electronic device outputs ~50W in thermal dissipation.

- No boundary conditions applied (chamber walls are non-conductive adiabatic).


The problem I'm having is that the device simulation internal temperatures - as well as those of the outer case - are ~20C higher than the physical test (thermo-couples are applied to various key locations during testing).  The physical chamber would naturally counteract the device dissipation by cooling the fan air to maintain the 55C ambient, but the problem I'm having is that I'm unsure on how to represent that phenomenon in the model.


All suggestions welcome.