Look into the material databases for many popular CFD simulation software packages, including Autodesk Simulation CFD, and you will find an entry for "solid" air. The solid phase is not normally associated with the atmosphere around us, so what gives?
Solid air (i.e., a solid material with the thermal properties of air) can be strategically used to optimize conjugate heat transfer simulations which have natural and/or forced convection.
In specific areas of certain models, the air flow and convection engine will be negligible and heat transfer by conduction will dominate. By eliminating the Navier-Stokes equations for fluid flow in these areas, the model becomes less complex while still maintaining overall solution fidelity. Bottom line is that you can get the same results in less time.
A few examples would include:
- Long narrow gaps between components that choke out air flow.
- An empty server rack in a data center used for cable storage.
- Small sealed electronics enclosures, such as thumb drives.
In this detailed technical video, we examine the use of the solid air material in CFD simulation using Autodesk Simulation CFD.
- Direct comparison of results:
- Using buoyant air
- Using solid air
- Calculating the Rayleigh number
- 3 minute duration