Extending an IFC-based Framework to include an Automated CFD-Setup using Pre-Computed Boundary Conditions

Computational Fluid Dynamic (CFD) simulations are used in building design, including design and performance optimization, as well as thermal comfort, fire, and evacuation simulations. However, even if CAD models of the building are available, setting up the CFD model and preprocessing the data require geometric simplification to reduce computational time and model healing. These preprocessing steps require high manual effort, which is, together with the computational cost, one of the main reasons why CFD is rarely applied in building design processes outside of research. Aiming to automize the CFD model setup, this paper describes the development of an IFC-based framework enabling the extraction of geometric data required for OpenFOAM CFD simulations. Our framework is based on the IFC Space Boundary geometry. This CFD-based setup is linked to IFCbased Building Performance Simulation (BPS) results that are used as boundary conditions for the CFD model setup. These BPS results are obtained from the open-source bim2sim tool, which generates IFC-based BPS models using EnergyPlus. Our preprocessed CFD models can be exported for OpenFOAM CFD simulations. Also, our proposed framework reduces the manual effort for CFD preprocessing via geometric generation and meshing. Through the open-source CFD-Kernel OpenFOAM, our framework fully integrates into the open-source bim2sim process. In further research, the resulting CFD models are then used for detailed IFC-based thermal comfort analysis.