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CAE Simulation

CFD Parameters: Fluid & Thermal Dynamics Validation

Computational Fluid Dynamics (CFD) at Edelweis is the digital wind tunnel and thermal laboratory for high-performance systems. We go beyond colorful heat maps to provide rigorous, physics-based data on flow behavior, pressure drops, and heat dissipation, ensuring thermal management systems are optimized for real-world efficiency.

1. The Fluid Physics Engine

We define the environment based on the specific molecular behavior of the medium, ensuring the solver respects thermodynamics and fluid mechanics laws:

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    Flow Regime Classification: Utilizing Reynolds Numbers (Re) to state state. Turbulent flows are modeled using k-ω SST or k-ε for boundary layer accuracy.
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    Compressibility: Analyzing high-velocity gas flows where density changes are significant (e.g., pneumatic exhaust).
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    Multi-Phase Flow: Simulating interactions between different states, such as liquid cooling with vapor bubbles (cavitation).

2. Thermal Management Protocols

We treat heat as a dynamic force impacting both mechanical integrity and electronic performance:

Conjugate Heat Transfer (CHT)
Solving for heat transfer between solid components and fluid streams simultaneously. Critical for heat sinks.
Volumetric Generation
Simulating heat from CPU/GPU dies or battery cells using precise W/m³ power density definitions.
Convection Strategies
Modeling both Natural (buoyancy) and Forced (fan/pump) cooling using real-world PQ Curve data.

3. Boundary Conditions (The "Environment" Logic)

Parameter Technical Implementation Engineering Utility
Inlet Profile Mass Flow Rate or Velocity Magnitude. Defining the exact volume entering the system.
Opening/Outlet Static Pressure (Ambient) or Environmental. Simulating open-air exhaust or return lines.
Wall Functions No-Slip with Roughness Parameters. Accounting for friction of internal pipe surfaces.
Periodic Boundaries Rotational or Translational Symmetry. Reducing cost for fans, turbines, or arrays.

4. Convergence & Mesh Rigor

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    Prism Layer Meshing: Inflation layers at walls to capture boundary layer velocity gradients, crucial for drag coefficients.
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    Residual Monitoring: Solutions are only accepted when residuals drop below 10⁻⁴ (standard) or 10⁻⁶ (high-precision).
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    Mass Flow Balance: Verifying that Sum(Mass In) = Sum(Mass Out) to ensure no fluid is leaking through the mesh.

Technical Directives

Directive Protocol
Y+ Optimization Mesh at walls must be sized for Y+ values appropriate to the turbulence model.
Steady vs. Transient Transient solvers must be used for start-up cycles or rapid thermal spikes.
Gravity Vector Must be aligned with Master Skeleton orientation to accurately model buoyancy.