Treat a CHT model as a heat-flow network. Every watt entering the model must have a physically defined path through fluids, solids, interfaces and external boundaries, and the final energy balance should close.
Define the thermal domains before selecting models
Identify which volumes are fluid, which are solid and whether any thin component should be represented with a shell or equivalent resistance instead of a full 3D solid. Preserve separate materials where conductivity or heat capacity matters.
Audit fluid-solid connectivity
A geometric touch is not enough. Verify that the simulation topology transfers heat across every intended fluid-solid and solid-solid connection. Check interface areas, contact coverage and whether any accidental wall or gap blocks the heat path.
Separate loads from heat-transfer responses
Apply known heat generation, heat flux, temperature, convection or radiation conditions according to what is actually known. Avoid imposing both a temperature and a heat rate on the same physical path unless the model formulation explicitly requires it.
Close the energy balance
Create reports for heat entering, heat leaving, volumetric sources and storage when transient. Large imbalance usually points to incomplete convergence, a missing boundary contribution, inconsistent sign conventions or an unintended interface.
Respect fluid and solid time scales
Fluids can respond much faster than massive solids. For transient thermal problems, choose timestep and simulation duration from the thermal time scales that control the engineering output rather than only from flow convergence.
Run the engineering check
Use the linked Abecator calculator or workflow to turn the setup decision into a quantitative check.
Continue the Abecator path
- CFD Verification Workflow
- Technical Case: CHT Energy Imbalance
- Thermal & CHT CFD Training
- Thermal & CHT CFD Consulting
Primary Siemens reference
STAR-CCM+ is a Siemens product name. Abecator is independent and this article is original engineering guidance; it does not reproduce Siemens documentation or third-party tutorial text.