Precise prediction of ventilation flow is essential to create a comfortable, economical, and healthy indoor environment. In the past three decades, the computational fluid dynamics (CFD) method has been used more often, and it is now one of the primary methods for studying building ventilation. The most common CFD method is RANS simulation because of the low cost of computational resources and good accuracy. This paper presents a numerical investigation of a transitional ventilation flow with the Coanda effect, which makes the initial free jet transform into a wall jet. Six low-Reynolds number k-ε models proposed by Abid (AB), Lam and Bremhorst (LB), Launder and Sharma (LS), Yang and Shih (YS), Abe Kondoh and Nagano (AKN), and Chang, Hsieh and Chen (CHC) are applied. The performance of the six models is evaluated by comparing the computational results with the PIV measurements of Van Hooff et al. The predictions revealed that the LS model has a good approximation of velocity profiles because of its two extra terms in k and ε equations, and the AB model is in good agreement with experimental results for predicting the Coanda effect. The LB model provides the worst agreement with experimental data on account of the wrong prediction of turbulent kinetic energy and dissipation rate.
A Low-Reynolds Number (LRN) k–ε model can well simulate the transition characteristics of the momentum boundary layer, but so far, there are few studies on the influence of boundary layer transition on heat transfer characteristics by using the LRN k–ε model. Due to the larger degree of flexibility and controllability of flow parameters than the conventional boundary layer, a wall jet is an ideal flow configuration to research the transition of the boundary layer. To investigate the performance of the LRN k–ε model in simulating the heat transfer characteristics of the wall jet with boundary layer transition, six versions of LRN k–ε models are used to simulate a three-dimensional wall jet with boundary layer transition and the computational results were compared with experimental data. It is found that the Abe–Kondoh–Nagano (AKN) and Yang–Shih (YS) models can accurately simulate the flow field and heat transfer of the laminar boundary layer due to the use of the Kolmogorov scale in the developing region. Compared with the YS model, the AKN model is capable of predicting the influence of boundary layer transition on the heat transfer process in good agreement with experimental results over the whole domain. From the calculation results, it is found that Abid and Change and Hsieh and Chen models are more appropriate for simulating the heat transfer in the fully turbulent region of the wall jet. The damping function fµ of the Lam–Bremhorst and Launder–Sharma models approaches a constant value near the wall, which does not meet the wall limiting conditions and leads to a negative impact on the simulation of heat transfer near the wall.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.