2University of Chlef, Laboratory of Control, Testing, Measurement and Mechanical Simulation, B. P. 151, 2000 Chlef, Algeria
3University of Chlef, Laboratory of Control, Testing, Measurement and Mechanical Simulation, B. P. 151, 2000 Chlef, Algeria
4Univ. Artois, Univ. Lille, IMT Lille-Douai, Junia, ULR 4515 – LGCg, Technoparc Futura, F-62400 Béthune, France
Abstract
Jet mixing ventilation using air is a well-known technology for providing thermal comfort in indoor environments. Jet diffusers are designed to maximize the effective dispersion of clean air and thermal energy for air conditioning or heating in an inhabited room. Jet diffusers are designed to improve mixing between jets and surrounding air and take aspects of aesthetic into account. However, the existing studies mainly focus on single jets or conventional multi-jet diffusers, and few studies have examined how central jet shape affects heat comfort and dynamic homogeneity. This paper presents a novel comparison of two multi-jet diffuser configurations. Both configurations consist of six peripheral jets of similar geometry, but the central jet is designed differently, one with a lobed central jet and the other with a swirling central jet. The originality of this
work lies in the systematic evaluation of these diffuser designs from experimental and numerical points of view, concerning their influence on dynamic homogenization and thermal comfort. This work is different from earlier studies in that it uses multiple turbulence models, such as the RNG k-ε, the standard k-ω, the (k-ω) SST and the RSM models to decide the best predictive method for jet interactions. It was found that the swirling diffuser improves thermal comfort and dynamic homogenization significantly without any increase in the pressure drop and sound pressure level as compared to the lobed diffuser. Quantitative results show that the swirling central jet improves the axial dynamic and thermal homogenization by about 20% and the radial dynamic and thermal homogenization by about 10% with respect to the lobed configuration. Furthermore, the present study shows that the Shear Stress Transport k-ω SST model can accurately predict the complex flow structures and
thermal characteristics of multi-jet diffusers, which can be a useful tool to optimize the geometric parameters of lobed and swirling perforated panels in heating, ventilation, and air conditioning systems. Also, the k-ω SST model showed better agreement with experimental data with root mean square error values of 0.0368 for axial velocity and 0.0384 for axial temperature. The results offer new insights into diffuser design
strategies for better indoor air distribution and energy efficiency.
