Paper Conference

Proceedings of BSA Conference 2017: Third Conference of IBPSA-Italy


A Comparative Study of Computational Algorithms Used in the Automatic Generation of Reduced-Order Models from CFD Simulations

Thibault Marzullo, Sajjad Yousefian, Marcus M. Keane, Marco Geron, Rory F.D. Monaghan

Abstract: In indoor thermal environment modelling applications where dynamic local effects of fluid flows are critical, classic zonal models are not always suitable. On the other hand, CFD simulations can give accurate solutions at very high computational cost. Reduced-order models (ROMs), extracted from CFD simulations, can preserve CFD model accuracy while being characteristically of low computational cost. The authors propose a method, known as CFDROM, capable of rapidly and automatically generating, from CFD simulations, zones, mass, and heat flows, and boundary conditions (BCs) for ROMs. This paper presents a comparative study of automatic zone generation algorithms as a necessary initial step to developing the CFDROM method. Zone generation algorithms compared in this paper are: (1) Mean Values Segmentation; (2) Classic Watershed; and (3) Coarse Grid Interpolation. The methods were compared on the bases of their accuracy against the original validated CFD simulation results, and their time to zone generation. The Mean Values Segmentation method yields promising results, providing a mean error below 0.2 K for 15-zone models generated in under 28 seconds. The next immediate steps for the development of CFD-ROM are (i) construction of a ROM solver, and (ii) testing its ability to predict thermal conditions when CFD BCs and ROM BCs differ.
Pages: 225 - 232