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Simulation & ValidationENGINEERING STUDY

Conjugate Heat Transfer & Thermal Analysis for Sealed Electronics Enclosure

In this computational fluid dynamics (CFD) study, YantriX modeled conjugate heat transfer (CHT) within a sealed outdoor electronics enclosure to predict internal air recirculation, conduction paths, and external fin heat dissipation without active fans.

By Rohit Jasoliya · Co-Founder · Mechanical Engineering Lead2 min readIndustrial IoT & Outdoor Telecommunications
CFD thermal analysis of sealed electronics enclosure showing heat distribution

Conceptual 3D thermal illustration — heat dissipation and fin architecture for a sealed IoT gateway enclosure

Overview

Engineering Scope & Context

CFD simulation study analyzing conjugate heat transfer (CHT), hotspot dissipation, and external heat sink fin geometry for a sealed electronics enclosure operating in 45°C ambient air.

Engagement: ENGINEERING STUDY

Discipline: Simulation & Validation

Project Type: Engineering Simulation (Conjugate Heat Transfer CFD Study)

Application: Industrial IoT & Outdoor Telecommunications

YantriX Scope Ownership

  • Fluid domain extraction for internal sealed cavity and external ambient air volume
  • Thermal component modeling: heat sources (SoC, power regulators, DC-DC converter)
  • Conjugate heat transfer (CHT) solver configuration combining conduction and natural convection
  • Boussinesq approximation for buoyancy-driven air density variations
  • Heat sink fin spacing, thickness, and orientation optimization for vertical convective flow
  • Hotspot identification and internal conduction spreader plate geometry recommendations
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Key specifications

Core engineering parameters & stack.

Hotspot Reduction
CFD Thermal Simulation Study
35 W
Total Heat Load (Simulation Input)
45 °C
Ambient Environment (Simulation Input)
Sealed Enclosure
Outdoor Electronics Thermal Design

Objectives

What the project needed to achieve

  • Construct a 3D conjugate heat transfer CFD model of a 35W sealed compute enclosure
  • Model natural convection airflow and radiation exchange at 45°C ambient temperature
  • Predict peak SoC junction temperatures under full computational load
  • Iterate external heat sink fin pitch and thickness to maximize natural convective airflow
  • Evaluate predicted processor junction temperatures against the study's 80°C design target

Challenge

Engineering constraint

The study examined a sealed outdoor compute enclosure with a modeled 35 W total heat load at 45°C ambient, where cooling depends on internal air circulation, conduction through chassis walls, and external natural convection. It evaluated how internal thermal paths and fin spacing affect predicted steady-state temperatures.

Approach

How YantriX approached the work

  1. 01

    Imported CAD geometry into ANSYS Fluent, simplifying non-thermal details while preserving internal component volumes.

  2. 02

    Specified volumetric heat generation rates for SoC (22W), power circuitry (8W), and radio module (5W).

  3. 03

    Applied conjugate solid-fluid interface boundary conditions with coupled heat transfer equations.

  4. 04

    Evaluated external fin spacing from 6 mm to 16 mm to determine the point where boundary-layer interference limits vertical buoyancy flow.

  5. 05

    Introduced an internal aluminum thermal heat pipe/spreader block coupling the primary SoC directly to the chassis casing.

Outcomes

What improved by the end

  • The simulation predicted elevated SoC junction temperatures when heat transfer relied on internal air conduction alone
  • The simulation indicated lower peak junction temperatures with a thermal block coupling the SoC to the top casing
  • The simulation identified 12 mm fin pitch as the best tested option for natural convective airflow in 45°C still air
  • The simulation predicted external casing temperatures below 55°C under the defined 45°C ambient operating condition; formal touch-temperature compliance verification was outside the scope of this study

Deliverables

Engineering Deliverables & Outputs

  • Comprehensive CFD simulation technical report with temperature and velocity vector plots
  • Thermal resistance network diagram and heat path breakdown
  • Optimized heat sink fin CAD solid model
  • Thermal interface material (TIM) thickness and conductivity specifications

Tools used

Stack and tooling

  • ANSYS Fluent (CFD)
  • SolidWorks CAD
  • Thermal Resistance Modeling

Impact

Business-level effect

  • Demonstrates how virtual CFD simulation de-risks thermal architecture before hardware layout and tooling investments are made

Conclusion

Thermal de-risking during the CAD phase is one of the highest-value applications of engineering simulation—catching component overheating before PCB fabrication and mold tooling commitment.

Working on a similar engineering problem?

Designing a sealed electronics enclosure or power hardware where thermal dissipation is critical? Send us your 3D CAD and power specifications for a thermal CFD analysis.

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Tagged

  • CFD
  • Thermal Analysis
  • ANSYS Fluent
  • Heat Transfer
  • Enclosures
  • Simulation

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