Coupling of a multizone airflow simulation program with computational fluid dynamics for indoor environmental analysis

Abstract

Current design of building indoor environment comprises macroscopIC approaches, such as CONT AM multizone airflow analysis tool, and microscopic approaches that apply Computational Fluid Dynamics (CFD). Each has certain advantages and shortfalls in terms of indoor airflow simulation. A coupling approach that combines multizone airflow analysis and detailed CFD airflow modeling would provide complementary information of a building and make results more accurate for practical design. The present study attempted to integrate such building simulation tools in order to better represent the complexity of the real world. The overall objective of this study was to couple an in-house CFD program, MIT-CFD, with a multizone airflow analysis program, CONT AM. Three coupling strategies were introduced. The virtual coupling makes use of the CFD simulation results in a large scale to provide boundary conditions for CONT AM. The quasi-dynamic strategy assumes that CFD can produce a "true" flow pattern and the CONTAM results should be changed accordingly. The dynamic coupling realizes an active two-way interaction between CFD and CONTAM through a bisection search procedure designed by the author that forces the airflow rates from the two models to converge. Various case studies were conducted to validate the coupling strategies. Preliminary results show that all three coupling schemes can result in more reliable airflow patterns. Further investigations are needed to improve the coupling procedures and to apply to more generalized and complex real-world cases.