Thermal simulation that shows where the heat goes
Thermal simulation predicts the temperature of every part of your product at the conditions it will meet in service, how quickly it heats up and cools down, and which design changes keep it inside its limits.
Temperature limits sit behind many product problems: a seal that hardens, an adhesive that softens, a battery cell that ages early, a surface too hot to touch, a sensor that drifts. The heat responsible usually takes several paths at once, conducting through joints and housings, convecting into the surrounding air or coolant and radiating to nearby surfaces. Estimating each path on its own rarely gives the temperature you will see on test.
More about thermal simulation
Thermal simulation solves those paths together on a model of the real geometry. Steady-state studies give the temperature once everything has settled. Transient studies follow temperature through time, which matters for warm-up, duty cycles, cool-down after shutdown and any product whose load changes faster than its thermal mass can respond. Where moving air or coolant carries the heat away, conjugate heat transfer solves the solid and the fluid in one model, so the flow that sets the temperatures is predicted rather than assumed.
SixGate™ is the design-to-manufacture process of F-CAD® in Glasgow, and its thermal studies are run by engineers who also design the parts. Each one is built around a decision: which material, which cooling arrangement, how much margin.
Typical products: electrical and control enclosures, battery packs, heaters and heated platens, LED lighting, motors and drives, catering equipment, laboratory and medical devices, and moulding tools.
What a thermal study tells you
How hot will it get?
Peak and average temperatures for every part at your worst-case ambient and load, set against the limit for each material and component.
How long can it run at full load?
Temperature through the duty cycle, showing how long the product can operate before a limit is reached and how long it needs to recover.
How long does it take to warm up?
Time for a heater, platen, oven or tool to reach working temperature, and how evenly the temperature settles across the working surface.
Which heat path matters most?
The share of heat leaving by conduction, convection and radiation, so effort goes into the path that will actually lower the temperature.
Is passive cooling enough?
Whether natural convection and radiation can carry the load, or whether forced air, a liquid loop or a better thermal path to the chassis is needed.
Will touchable surfaces stay within limits?
Predicted temperatures on handles, housings and controls, compared with the touch temperature limits in the standard you specify.
What we model
Conduction
Heat flow through solids and across joints, including thermal interface materials, contact resistance and circuit boards whose in-plane conductivity far exceeds their through-thickness value.
Natural convection
Buoyancy-driven airflow around passive products and inside sealed enclosures, where orientation and internal layout change the result.
Forced convection
Fans, blowers and pumped coolant, with the flow solved directly or represented by heat transfer coefficients where that is sufficient.
Radiation
Surface-to-surface exchange and the effect of emissivity, which becomes significant at high temperature and in still air.
Conjugate heat transfer
Solid and fluid solved together, so component temperatures and the airflow or coolant flow that sets them come from one consistent model.
Steady state and transient
Settled temperatures at a constant load, or temperature through time for warm-up, cool-down, duty cycles and power pulses.
Thermal management design
Cooling strategies compared, including heat spreaders, fins, vents, fans, cold plates and heat pipes, ranked on temperature, size and cost.
Temperature-dependent properties
Conductivity and specific heat of solids, and density and viscosity of fluids, varying over the working temperature range.
Before you start
What to send us
- CAD of the product and the enclosure, frame or mounting it sits in
- Heat loads: power per component or heater, and how it varies over time
- Ambient conditions: air temperature, coolant temperature and flow, nearby hot surfaces
- Materials, including interface pads, coatings and surface finishes
- Temperature limits for components, materials and touchable surfaces
- The duty cycle or operating profile, for transient studies
Steady state or transient: which do we need?
Steady state suits products that run at a constant load for longer than they take to warm through. Transient is needed when loads cycle, when warm-up time matters, or when the product never runs long enough to settle and a steady-state result at peak load would be needlessly pessimistic.
Do you always need to model the airflow?
No. Where the air side is well understood, heat transfer coefficients on the surfaces give useful answers quickly. As a guide, natural convection in air gives roughly 2 to 25 W/(m² K) and forced air roughly 25 to 250 W/(m² K); where airflow is restricted or fan-driven, conjugate heat transfer is the better choice.
Can the temperatures feed a stress analysis?
Yes. Applied to a structural model, the temperature field predicts expansion, distortion and thermal stress, which is the subject of our thermal stress analysis service.
What if we do not know the power dissipation exactly?
Send your best estimate and its likely range. Running the study at both ends of the range shows whether the uncertainty changes the design decision.
Tell us what runs hot
