Avionics Thermal Control CFD Simulation

A computational fluid dynamics study investigating how inlet airflow speed affects forced-convection cooling of a heated aircraft electronics box.

The project modeled a two-dimensional airflow domain in Ansys Fluent with cool air entering from the left, flowing over a heated rectangular electronics component, and exiting through a pressure outlet.

The objective was to determine how increasing inlet airflow speed affects heat removal and temperature behavior within an aircraft electronics cooling configuration.

This project was completed independently.

• Developed the two-dimensional aircraft electronics cooling model in Ansys Fluent.
• Defined the velocity inlet, pressure outlet, heated electronics surface, no-slip walls, and adiabatic boundaries.
• Enabled coupled airflow and heat-transfer physics using the energy equation.
• Generated and compared coarse, medium, and fine computational meshes.
• Evaluated numerical stability using average outlet temperature and monitored solver residuals.
• Conducted a parametric airflow-speed study from 0.5 m/s to 2.0 m/s.
• Analyzed velocity vectors, temperature contours, heat-transfer rate, maximum static temperature, and average outlet temperature.
• Interpreted results and prepared the final technical report.

The CFD model represented a simplified aircraft electronics cooling problem. Air entered a rectangular flow domain through a velocity inlet, passed over and around a heated electronics box, and exited through a pressure outlet.

The same geometry and thermal conditions were maintained for each airflow case. Only inlet velocity was changed so that changes in cooling performance could be attributed directly to airflow speed.

Radiation was excluded because the study focused on forced convection, and the electronics box was treated as rigid and stationary.

Mesh convergence was evaluated before beginning the airflow-speed study.

Three meshes were compared using average outlet temperature as the primary convergence metric.

All three outlet-temperature values remained close to 300.3 K, indicating that the preliminary numerical solution was reasonably stable as the mesh was refined.

Increasing inlet airflow improved forced-convection cooling performance.

Heat-transfer rate increased substantially as airflow speed increased, while maximum static temperature decreased.

Average outlet temperature also decreased because the higher-speed cases moved more air through the domain. Each unit of air experienced a smaller temperature increase, even though the total heat removed from the electronics box increased.

The simulation demonstrated a direct relationship between inlet airflow speed and convective heat removal.

Stronger forced convection increased heat-transfer rate and reduced peak temperature near the electronics box, supporting both original hypotheses.

The project represents a simplified aerospace thermal-management problem and demonstrates how CFD can be used to compare cooling strategies before physical testing.