Example: Electronics Cooling

Example: Electronics Cooling#

This example demonstrates setting up a thermal management simulation for an electronics enclosure. You’ll model airflow over heat-generating components and evaluate cooling effectiveness.

Objective#

  • Generate a mesh for an electronics enclosure with heat-generating components

  • Run a simulation to evaluate airflow and temperature distribution

  • Identify hot spots and areas of poor cooling

  • Compare different cooling configurations

Step 1: Create a Meshing Project#

  1. Dashboard → New Project → Meshing

  2. Name: “Electronics Cooling”

  3. Upload your enclosure geometry (STEP format)

Step 2: Geometry Preparation#

Electronics cooling geometries typically include:

  • Enclosure — The outer housing that contains the electronics

  • Components — PCBs, processors, heat sinks, fans

  • Vents — Intake and exhaust openings

Geometry Simplification

For CFD, simplify your geometry:

  • Remove small features (screws, labels, textures) that don’t affect flow

  • Close small gaps that the mesh can’t resolve

  • Combine parts that aren’t thermally distinct into single bodies

  • Keep heat sinks and other flow-critical features

The AI Assistant can suggest which features to keep and which to remove.

Step 3: Domain Configuration#

  1. Select Internal Flow (if air flows through the enclosure via vents)

  2. The fluid volume is the air inside the enclosure

  3. Identify inlet vents and outlet vents as surfaces

For conjugate heat transfer (modeling solid heat conduction through heat sinks):

  1. Select Conjugate Heat Transfer (CHT) domain type

  2. Define fluid region (air inside the enclosure)

  3. Define solid regions (heat sink, PCB, processor package)

Step 4: Multi-Region Setup (CHT)#

Regions#

Region

Type

Material

air

Fluid

Air (ρ = 1.225 kg/m³, μ = 1.81e-5 Pa·s)

heatsink

Solid

Aluminum (k = 205 W/m·K)

pcb

Solid

FR4 (k = 0.3 W/m·K)

Interfaces#

Interface

Regions

Type

air_heatsink

air ↔ heatsink

Perfect contact

heatsink_pcb

heatsink ↔ pcb

Contact resistance (if thermal paste modeled)

Step 5: Surface Naming#

Surface

Name

Condition

Intake vent

inlet

Velocity inlet

Exhaust vent

outlet

Pressure outlet

Enclosure walls

enclosure_wall

No-slip wall (adiabatic)

Processor top

processor

Heat flux wall (e.g., 65 W)

Heat sink fins

heatsink_surface

No-slip wall (coupled for CHT)

Step 6: Mesh Settings#

Parameter

Value

Target cell size

5 mm

Min cell size

0.5 mm

Refinement levels

8

Boundary layers

Enabled (fluid region only)

BL layers

5

First layer height

0.1 mm

Growth rate

1.2

Refinement Zones#

Zone

Location

Cell Size

Purpose

Heat sink region

Around heat sink fins

1 mm

Resolve fin gaps

Vent regions

At intake/exhaust openings

2 mm

Resolve jet flows

Component zone

Around hot components

2 mm

Thermal resolution

Step 7: Simulation Setup#

Setting

Value

Turbulence model

k-ω SST

Inlet velocity

Based on fan curve (e.g., 2 m/s)

Outlet pressure

0 Pa

Enclosure walls

Adiabatic wall (no heat loss)

Processor surface

Heat flux: 65 W / surface area

Turbulence intensity

5%

Max iterations

1000

Step 8: Results Analysis#

Temperature Distribution#

  1. Color surfaces by Temperature

  2. Identify the maximum temperature on the processor

  3. Check that the maximum temperature is below the thermal design limit (typically 85–100°C)

Airflow Patterns#

  1. Add streamlines seeded from the intake vent

  2. Trace the airflow path through the enclosure

  3. Identify:

    • Areas with good airflow (near vents, through heat sink)

    • Dead zones with stagnant air (poor cooling)

    • Short-circuiting paths (air going directly from inlet to outlet without cooling components)

Heat Sink Performance#

  1. Add slice planes through the heat sink fins, colored by velocity

  2. Check that air flows through all fin channels

  3. Low-velocity or recirculating regions indicate poor heat sink utilization

Hot Spot Identification#

  1. Color all solid surfaces by temperature

  2. Hottest regions indicate inadequate cooling

  3. Common hot spots:

    • Components far from airflow path

    • Areas behind flow obstructions

    • Stagnation zones between closely packed components

Design Optimization Workflow#

  1. Baseline — Run the initial configuration and record temperatures

  2. Modify — Adjust vent positions, fan speed, or heat sink design

  3. Re-mesh — Generate a new mesh for the modified geometry

  4. Re-simulate — Run the simulation with the same conditions

  5. Compare — Check if maximum temperature decreased

Common Improvements#

Change

Effect

Increase fan speed

Lower temperatures, more noise

Add/reposition vents

Better airflow to hot spots

Larger heat sink

More surface area for cooling

Thermal pads/paste

Better component-to-heatsink contact

Baffles/guides

Direct airflow to problem areas
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