Cooling Fan CFD Seeding for Faster Idling Vehicle Thermal Simulation

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Solution Overview

Problem

Existing thermal simulation methods for idling vehicles with operating cooling fans face high computational costs and prolonged simulation times due to the need for fine meshing and slower air movement, which is not effectively addressed by current techniques like transient boundary seeding (TBS) when turbulence structures are less critical for thermal management.

Innovation Solution

A two-stage Computational Fluid Dynamics (CFD) method using a transient boundary seeding (TBS) box to record transient flow information around the cooling fan, followed by removing the fan in a second stage simulation, reducing computational cost and time while maintaining accuracy by mapping scalar fluid variables from the upstream to downstream.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a fine mesh is used to accurately resolve the flow around the cooling fan, then the accuracy of the thermal simulation is improved, but the computational cost and simulation time increase significantly

Engineering Contradiction:

Improveaccuracy of thermal simulationVSAvoidsimulation time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The simulation is divided into two distinct stages: a first stage that captures transient flow information using a coarser mesh, and a second stage that uses the captured data to seed boundary conditions for a faster thermal simulation. This segmentation allows each stage to use appropriate mesh resolution for its specific purpose, reducing overall computational cost while maintaining accuracy.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The first stage simulation performs preliminary capture of transient flow structures and turbulence characteristics before the second stage thermal simulation begins. This preliminary action provides pre-computed boundary conditions that eliminate the need for expensive fine mesh simulations during the thermal analysis phase, significantly reducing simulation time while preserving accuracy.

Inventive Principle:

Principle #10Preliminary action

2Measurement precision

If the cooling fan is included in the simulation model to accurately represent the flow driver, then the accuracy of the flow field prediction is improved, but the computational cost increases

Engineering Contradiction:

Improveaccuracy of flow field predictionVSAvoidcomputational cost

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The cooling fan is extracted from the second stage simulation domain and replaced with a boundary condition that imports transient flow information from the first stage. This extraction eliminates the need to resolve the complex fan geometry and its associated flow structures in the expensive fine mesh thermal simulation, reducing computational cost while maintaining flow field prediction accuracy through the imported data.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of directly modeling the cooling fan geometry in the second stage, the simulation copies the transient flow characteristics and turbulence structures captured during the first stage into the boundary conditions. This copying approach preserves the essential flow physics without requiring the expensive computational resources needed to resolve the fan geometry directly.

Inventive Principle:

Principle #26Copying

3Loss of time

If transient boundary seeding is used to reduce computational cost, then the simulation time is reduced, but the accuracy is compromised when turbulence structures are not fully captured

Engineering Contradiction:

Improvesimulation timeVSAvoidaccuracy of thermal management simulation

Core Design Contradiction:

Loss of timeVSMeasurement precision

Solution Approach 1:

The first stage simulation applies local refinement around the cooling fan and critical flow regions to accurately capture transient flow structures and turbulence characteristics. This localized quality enhancement ensures that the most important flow features are resolved with sufficient accuracy, providing reliable boundary conditions for the second stage thermal simulation while keeping overall computational cost manageable.

Inventive Principle:

Principle #3Local quality

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The method significantly reduces simulation time by up to 30% without compromising accuracy, optimizing thermal simulation efficiency for idling vehicles and heavy-duty machinery.

Implementation Method 1

mapping scalar fluid variables from the upstream to downstream

Methodology Applied

Scientific EffectConvection: Convection

Data Source

PatentUS20250342294A1Method for Efficient Thermal Simulation of Machinery or an Idling Vehicle with an Operating Cooling Fan

Publication Date: 2025.11.06 DASSAULT SYSTEMS AMERICAS CORP

AI summary

A Computational Fluid Dynamics (CFD) thermal simulation model simulates thermal conditions in a flow field of idling stationary vehicle during operation of a cooling fan. A first transient boundary seeding (TBS) box is defined around the cooling fan in the CFD model. A first stage simulation run of the CFD model records transient flow information. The cooling fan is removed from the TBS box for a second stage simulation run seeded with the transient flow information from the first stage simulation run.