Airflow Simulator

This project simulates the relative airflow balance of a Fractal Define 7 XL case with the configured fan layout.

It is not a CFD simulator and it does not calculate real CFM. It uses RPM, fan direction, and the restriction values in fan_config.ini to estimate relative intake, exhaust, and pressure balance.

Files

• airflow_simulator.py - Python/Tkinter GUI source.
• fan_config.ini - Fan curves, sensor sources, direction, position, and restriction values.
• dist\Define7XL_Airflow_Simulator.exe - Standalone Windows executable.

Run The Standalone EXE

Open:

dist\Define7XL_Airflow_Simulator.exe

The executable does not require Python to be installed on the target PC.

The EXE includes an internal copy of fan_config.ini. If you want to customize fan curves or restrictions for the EXE version, place a fan_config.ini file in the same folder as Define7XL_Airflow_Simulator.exe. That external file will be used instead of the embedded one.

Run From Python

python airflow_simulator.py

Python mode requires only the Python standard library and Tkinter.

How To Use

• Move the temperature sliders to simulate different CPU, VRM, motherboard, and chipset temperatures.
• Fan RPM updates automatically from the curves in fan_config.ini.
• Animated lines inside the case show the estimated airflow and turbulence.
• Static arrows next to each fan show the configured intake/exhaust direction.
• The pressure panel inside the case shows current relative pressure and whether the 20-90 C slider range stays positive.

Edit Fan Curves

1. Open fan_config.ini.
2. Edit the curve = temp:rpm,temp:rpm,... lines.
3. Save the file.
4. In the GUI, click Ricarica fan_config.ini.

Relative Pressure Model

The simulator uses:

relative_flow = rpm / max_fan_rpm * restriction

Positive pressure means relative intake is higher than relative exhaust. Negative pressure means relative exhaust is higher than relative intake.

Use restriction to model airflow losses from radiators, dust filters, front panels, mesh, or grilles.