Numerical and experimental analysis of the air stream generated by square ceiling diffusers

Jaszczur, Marek; Madejski, Paweł; Kleszcz, Sławosz; Zych, Marcin; Palej, Patryk

doi:10.1051/e3sconf/201912808003

Cited by 7 publications

(3 citation statements)

References 11 publications

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“…The supply airflow of each terminal is not independent within the room, but rather has a mutual influence due to the air movement. The airflow distribution on the outlet cross-section of the diffuser directly determines the mixing effect of neighboring airflows, which has an impact on the indoor temperature distribution [30,31]. The current methods do not fully consider the mutual influence among diffusers and their co-impacts on indoor temperature distribution.…”

Section: Introductionmentioning

confidence: 99%

Simplified Simulation Method of Diffusers for Indoor Non-Uniform Temperature Distribution: A Case Study in Shanghai

Li,

Pan,

Huang

et al. 2024

Buildings

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The specific air jet of a diffuser is formed by the complex internal structure, which affects the outlet airflow distribution of the diffuser directly and the indoor environment distribution indirectly. If the diffusers are developed based on their actual geometry structure and their boundary conditions are set as their inlet flowrate, the simulated indoor temperature distribution will be more accurate. However, it is noted that many problems may arise, such as model complexity, many grid cells, and slow convergence of calculations. Therefore, this paper focuses on a simplified method for four-way square diffusers in a computational fluid dynamics (CFD) simulation of indoor non-uniform temperature distribution. Firstly, the airflow distribution is simulated on the outlet air supply cross-section of the diffuser. Then, according to the outflow characteristics of the diffuser, the diffuser model is simplified and simulated in an experimental room. Finally, the temperature distribution at the 1.2 m height plane is obtained from CFD simulation and compared with the experimental results. The results show that the 68-point air supply opening model can well simulate the effects of the outlet airflow distribution of the diffuser, and the simulated indoor temperature distribution meets the experiment results well. The deviations for three scenarios are between −7.4~1.7% and the average deviation is −3.0%, while the root mean square error of temperature for three scenarios is 0.7 °C, 0.7 °C, and 1.0 °C, respectively. The results also demonstrate the mutual influence of the airflow from different diffusers and the indoor non-uniform temperature distribution under the action of multiple diffusers. The proposed method can contribute to balancing the model complexity and the accuracy in CFD simulation, especially for multiple diffusers in the room.

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Section: Introductionmentioning

confidence: 99%

Simplified Simulation Method of Diffusers for Indoor Non-Uniform Temperature Distribution: A Case Study in Shanghai

Li,

Pan,

Huang

et al. 2024

Buildings

View full text Add to dashboard Cite

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“…Finally, it was concluded from the study that the multi-cone diffuser was a better overall performer among the two. Jaszczur et.al 10) performed a study of the air stream generated by the square ceiling diffusers. An experimental and numerical study of a single square ceiling diffuser was performed.…”

Section: Introductionmentioning

confidence: 99%

Simulating the Fluid Flow via Ceiling Diffuser Using OpenFOAM

Gupta¹

2023

Evergreen

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HVAC (heating ventilation and air conditioning) deals with cooling and heating buildings and providing clean conditioned air for indoor environments such as commercial office spaces, cinemas, and hotels to name a few. Diffusers help to effectively distribute air coming from HVAC ducts into indoor environments. Understanding the flow distribution from the diffuser is of great significance as it helps in locating the optimal location for the diffuser as well helps in designing a better diffuser. With the advent of high-performance computing, numerical simulation is mainly being used to predict airflow via Computational fluid dynamics (CFD). OpenFOAM is an open-source CFD solver written in C++ for solving fluid dynamics problems. In this work, a free architecture design tool called PCON was used to create the geometry of the office/home along with the furniture. OpenFOAM was used to create a mesh and simulate the flow through a square ceiling diffuser and understand the Coanda effect which is created by such a diffuser. Open source code called Paraview was used to analyze the CFD simulations and the results were reported in this paper. In central A/C systems, Freon has been used for decades. Freon, just like R12, has been linked to environmental damage. This work shows how diffusers can help with the efficient distribution of conditioned air in closed spaces. With the efficient distribution of air, Freon would be used less and in turn, more efficiently in a given space. This could prevent environmental damage to some extent.

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“…The way air is distributed into the room is closely related to the construction of the air diffuser. A number of research studies on air distribution from diffusers can be found in the literature [7,8], including those using a numerical calculation [9,10]. Yao and Lin [11] analyzed the effect of air terminal types on the performance of stratum ventilation with four types of air terminals devices using experimental and numerical methods.…”

Section: Introductionmentioning

confidence: 99%

Analysis of the Velocity Distribution in the Plenum Box with Various Entries

et al. 2021

Self Cite

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The ventilation system plays a crucial role in every building. Proper design and optimization of its operation increase the comfort of users due to efficient air exchange and at the same time control its velocity in the rooms. The aim of this paper is the analysis of the effect of plenum box entry on the velocity profile concerning the diffuser face panel. This issue may sometimes be ignored at the design stage but can significantly affect the airflow from the diffuser and consequently increase the risk of draft. The results of the PIV experimental measurements and numerical simulations concerning various entries of the plenum box (top and side) were investigated in this study. The measurements were used to develop the mathematical and numerical models, which were then used to assess the effect of localization of the spigot of the plenum box on its operation. The numerical analysis was carried out on plenum boxes with the air diffuser with a face panel composed of square grid perforations. Analyses show that the entries significantly affect both the way of air distribution inside the plenum box and the profile of the airflow and its velocity under the simulated air diffuser.

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Numerical and experimental analysis of the air stream generated by square ceiling diffusers

Cited by 7 publications

References 11 publications

Simplified Simulation Method of Diffusers for Indoor Non-Uniform Temperature Distribution: A Case Study in Shanghai

Simplified Simulation Method of Diffusers for Indoor Non-Uniform Temperature Distribution: A Case Study in Shanghai

Simulating the Fluid Flow via Ceiling Diffuser Using OpenFOAM

Analysis of the Velocity Distribution in the Plenum Box with Various Entries

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