Automated IFC-based mesh refinement and quality control for indoor airflow simulations using OpenFOAM

Computational fluid dynamics (CFD) simulations are an essential tool for indoor airflow simulations and in the design process of energy-efficient buildings. Setting up CFD models typically demands considerable manual effort, including the modeling of geometry, defining boundary conditions, and meshing. This complex and labor-intensive process can be streamlined by automatically generating indoor CFD models from IFC-based Building Information Modeling (BIM) models. To integrate this CFD model setup in an existing tool, a plugin for the IFC-based multi-domain bim2sim simulation environment with the open-source CFD library OpenFOAM was developed, including automated meshing and refinements. As the accuracy of simulation results highly depends on the mesh quality, the mesh must satisfy specific quality criteria. Furthermore, balancing a sufficiently detailed solution provided by finer grids and reasonable runtimes is a persistent challenge in CFD.This paper presents algorithms for automatic IFC-based mesh refinement for interior elements like radiators and air terminals. These algorithms are evaluated by refinement studies and a mesh quality analysis in a case study of a single office. The proposed optimal grid refinements can be used in further research to automatically set up CFD simulations for IFC-based thermal comfort analysis.