LiveInteractive demo
Forced-air cooling of a power board
Drag the parts around. Airflow, board temperature and every junction temperature are solved live in your browser, from real flow and heat-transfer physics.
Try: push Q1 against Q2 · drag a MOSFET to the board edge · drop the fan to 0.5 m/s · switch to 4-layer copper
25 °C100 °Cboard temperature
25 °C40 °Cair temperature
01.6 × fanair speed
- Flow
- Airflow2D incompressible flow on a staggered grid, with pressure projection
- ChannelFriction from the enclosure walls above and below the board
- Tall partsThe inductor and capacitors are solid obstacles, so wakes and vortex shedding form behind them
- Heat
- BoardCopper and FR4 conducting sheet, with each part's power as a heat source
- ConvectionFollows the local air speed (laminar flat-plate correlation); the air carries the heat downstream
- RadiationFrom the board and the package tops to the enclosure, growing with temperature
- Package topsLow-profile parts also shed some power through their own top surface
- Heat balanceAt the default settings about two thirds goes into the air, a fifth through the underside and the rest is radiated
- Junctions
- TemperatureBoard temperature under the part plus the board-side power × junction-to-board resistance, from typical datasheet values
- Design limitsSet below the rated maximums: MOSFETs 110 °C (rated 150–175 °C), electrolytics 85 °C (rated 105 °C; life halves every 10 °C), MCU 85 °C, inductor 100 °C, regulator 105 °C
- Limits
- ScopeA 2D, depth-averaged model on a 0.8 mm grid: right for trends and layout intuition, not for sign-off
- Full designA real board gets a full 3D conjugate heat-transfer model in Icepak or OpenFOAM
Want this for your own board?
The same physics, in full 3D and with your geometry, materials and airflow.