Why does my electronics cooling design pass simulation and still overheat on the bench?
A board or enclosure design clears its CFD run with comfortable margin, and then the first prototype runs hotter than predicted — sometimes by 10 °C or more. The usual suspects are a fan curve that doesn't match the datasheet at the installed operating point, a compact thermal model built on assumed junction-to-case resistance instead of a measured one, or a leakage path the CAD-derived mesh never captured.
Engineering teams end up in a loop of re-meshing, re-running, and adjusting boundary conditions to match a single data point from one prototype, without knowing whether the fix generalizes to the next design revision or the next lot of parts.
- Component-level thermal resistance values from datasheets are typically measured in a JEDEC standard environment that has little in common with your actual board and enclosure
- Contact resistance at TIM interfaces varies with applied pressure, surface finish and cure state — inputs that are rarely known accurately at model-build time
- Airflow bypass and recirculation paths are sensitive to small manufacturing tolerances that CAD-ideal geometry does not represent
- Fan curves published by vendors are measured in free air, not against the system impedance your enclosure actually presents
- Without a measured reference point, there is no way to know whether a 10 °C simulation-to-hardware gap is a meshing error, a boundary condition error, or a real physical effect
- Build the board, enclosure or rack model in Flotherm or FLOEFD with SmartParts and automated meshing
- Resolve conjugate heat transfer, natural/forced convection and radiation across the full assembly
- Escalate to STAR-CCM+ for two-phase, immersion or radiation-dominant physics when air-cooling assumptions break down
- Characterize the actual device thermal transient response with Simcenter Micred T3Ster to obtain a real compact thermal model
- Measure in-situ TIM performance in the real assembly stack-up with Simcenter Micred DynTIM instead of assuming a datasheet conductivity
- Import the measured CTM and TIM resistance directly into the Flotherm or FLOEFD model as boundary conditions
- Re-run the simulation against the measured baseline and quantify residual error before committing to a design direction
- Use the correlated model — not the as-built prototype — as the basis for the next design iteration
Electronics-focused CFD for PCB, enclosure and rack cooling design
CAD-embedded thermal analysis for early design-stage checks
Measured device thermal transient response and compact thermal models
In-situ TIM characterization for accurate contact resistance inputs
- JEDEC JESD51 package characterization
- ASHRAE TC 9.9
- NEBS GR-63-CORE thermal
Correlate your cooling design against measured device behavior.
Tell us what's overheating and what your current model assumes. We'll help you find where simulation and measurement diverge.