CFD Benchmark Tests for Indoor Environmental Problems: Part 1 Isothermal/Non-Isothermal Flow in 2D and 3D Room Model

Abstract

Commercially available Computational Fluid Dynamics (CFD) software have been applied in indoor environmental design in recent years, but the prediction accuracy depends on an understanding of fluid dynamics fundamentals, in setting appropriate boundary and numerical conditions. This study aims to provide practical modelling information related to prediction accuracy and problematic areas in CFD applications in air conditioning and ventilation, through a series of benchmark tests and reported the results. Six commercial CFD codes were evaluated while two benchmark test cases were performed on isothermal/non-isothermal flow in 2D and 3D room models. The influence of mesh design, and turbulence models showed that using a standard k-ε model on a coarse mesh could provide sufficiently accurate results for practical purposes, by reducing the relaxation coefficient. Evaluation using different CFD programs on a non-isothermal room airflow showed different performances in predicting temperature distributions. The OpenFOAM code showed the closest matching results between three codes tests.

Computational fluid dynamics modelling of the visible light photocatalytic oxidation process of toluene for indoor building materials with locally doped titanium dioxide

“…51 Regarding the quality control of the CFD simulation, we carefully selected the scheme, algorithm and other numerical/boundary condition settings and followed the guidelines and benchmarks for the analysis of airflow fields in enclosed spaces. [52][53][54][55] The prediction accuracy of CFD analysis in the chamber was validated by using experimental result in terms of the convective mass transfer flux and confirmed to be reasonably consistent with the results of measurement via the naphthalene sublimation technique and simulation. 39 In this study, the calculation result of the airflow field as given in the previous report 39 was utilized for investigating the concentration distribution and identification of model parameters as described by equations (20) to (22).…”

Coupled Simulations of Indoor-Outdoor Flow Fields for Cross-Ventilation of a Building in a Simplified Urban Array

“…Namely, at least 1/10 grids of building height are recommended for the RANS simulation of the outdoor flow field, as a guideline [22]. In addition, Ito et al [23] have shown that only two grids at the inlet position does not cause a large discrepancy in the indoor flow field distributions. The definitions of the openings are shown in Figure 1c, and the positions of the openings were chosen from three locations, denoted as 1, 2, and 3, in the vertical, and 1 and 2 in the spanwise directions.…”

Folded roof house—Design solution to optimize environmental conditions with generic equipment and techniques

“…The following performances were analyzed with environmental simulation techniques: (i) Optimization of the window opening position by solar radiation and indoor light environment analysis; (ii) Natural/cross-ventilation design supported by computational fluid dynamics (CFD) simulation [10][11][12] ; (iii) Optimization of opening position of horizontal slit-type windows using wind pressure coefficient analysis with CFD; and (iv) Annual heat load calculations to optimize the thermal insulation and natural/mechanical ventilation. Since the numerical simulation/analysis tools provide deterministic information for environmental conditions, the flexibility of design might decrease greatly when aiming at environmental optimization.…”