Fluid-Solid Heat Transfer

Fluid-solid heat transfer simulations model heat transfer within and between fluids and solids to allow analysis of temperature distribution in both regions.

The models can comprise multiple solid materials and separate flow paths with different fluid materials.

In fluid-solid heat transfer simulations, bodies are automatically identified as being solid or fluid based on the conditions or materials applied. Interfaces are automatically detected between fluid and solid bodies. These interfaces enable heat to be perfectly conducted between the fluid and solid bodies. The fluid side of the interface is treated as a non-slip wall, that is, zero velocity. Bonded contacts are detected between solid bodies, enabling conduction of heat between them. The effect of insulation between solid bodies can be modeled by converting a bonded to a excluded contact. Sliding contacts and other structural conditions cannot be modeled in combination with a fluid-solid heat transfer simulation.

There may be times when you run into issues while modeling fluid-solid heat transfer. Discovery issues warnings and messages to help you resolve the problems. The table below lists possible issues you might face and suggestions on how to resolve them.

Issue	Resolution
A fluid body is not included in the simulation, but it does not need to have any flow conditions applied. How can I add it to the physics?	Assign a fluid material to the body, then add it to the physics. If the whole fluid region is closed, that is, there are no flow conditions on any of its external faces, apply a wall boundary to a face. In this way convection due only to buoyancy can be simulated.
The interfaces and contacts are not created and there is no heat transfer between the bodies.	Check the geometry of the model for interference, such as overlapping volumes or gaps. Use Show > Body Interference in the Display tab to find areas of interference. Interference can also occur if the model has been made overly complex by the creation of multiple artificial bodies. To detect and fix overlapping volumes, use the Interference tool.
A fluid-solid interface includes a face shared between fluid bodies and there is no flow or the simulation cannot be solved.	The fluid face contacts faces of both solid and fluid bodies. Use the Imprint tool to split the face.
A face appears in both a fluid-solid interface and a contact and there is no heat transfer between the bodies.	The solid face contacts faces of both fluid and solid bodies. Use the Imprint tool to split the face.
Contact is detected between bodies, but the amount that they overlap is small, and the heat loss or gain could be better defined manually.	If imprinting or splitting the surface is not possible or appropriate, then exclude contact between the surfaces, and apply a solid-thermal condition to better model the heat transfer.
Contact is detected between bodies, but in reality there is a small insulating layer between them.	Convert the contact in this location to be excluded.
My model comprises layers of solid lining the inside of a pipe, but the fluid interface is detected by both the lining and the pipe.	Change the Detection distance for the fluid-solid interface. Click on the right side of the Interface Review HUD to see this option.
My model has many thin parts. How can I find out what parts are captured in the simulation?	Use Resolution in the Simulation tab ribbon to find and visualize the areas in the geometry that are not being captured in the simulation. Use in conjunction with Size Preview. Identified areas appear in red. Increase fidelity to include more geometry. This is available in Explore.