Comparative studies on isothermal attachment ventilation based on vertical walls, square and circular columns

Han, Ou; Li, Angui; Yin, Haiguo

doi:10.1016/j.enbuild.2020.110634

Cited by 18 publications

(4 citation statements)

References 25 publications

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Section: Introductionmentioning

confidence: 94%

“…After contacting the floor, the airflow changes direction horizontally, creating an attachment flow pattern on the floor. This results in a velocity distribution within the working area similar to that of displacement ventilation [31]. Research on the effects of wall impinging jet and displacement ventilation was also compared, and the flow characteristics of multiple confluent jets along vertical walls were studied.…”

Section: Introductionmentioning

confidence: 99%

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Numerical Study of Air Distribution and Thermal Environment in Attached Ventilation Mode in the Generator Layer of a Hydropower Station

Ren,

Li,

et al. 2024

Buildings

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Because they are in enclosed underground buildings, the generator layers of hydropower stations have limited ventilation. In order to reduce the influence of a hot and humid environment on equipment and staff health and create a good thermal environment with good air quality for underground buildings, in this paper, vertical wall-attached ventilation was combined with the generator layer of a hydropower station to replace traditional ventilation. The influence of air supply velocity, air supply outlet position, and the opening mode of the generator layer on indoor velocity and temperature field distribution were analyzed via numerical simulation, and the evaluation indices of different cases were also compared. In the single-sided vertical wall-attached ventilation mode, when the velocity was increased from 4 m/s to 8 m/s, the maximum increment in the energy utilization coefficient was 41%, and the maximum reduction in the velocity non-uniformity coefficient was 9.5%. The results show that the single-sided mode can offer a higher ventilation efficiency than the double-sided mode, with a higher energy efficiency and a more uniform air distribution. Based on the mean temperature and velocity, and the key evaluation indices (head-foot temperature difference, percentage of dissatisfaction, non-uniformity coefficient, energy utilization coefficient, and air diffusion performance index), it is suggested that the single-sided air supply mode should be adopted for this kind of tall building, with an air supply velocity of v = 6 m/s and two open air supply outlets at each interval.

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Section: Introductionmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Numerical Study of Air Distribution and Thermal Environment in Attached Ventilation Mode in the Generator Layer of a Hydropower Station

Ren,

Li,

et al. 2024

Buildings

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show abstract

“…In another study, Han et al [6]undertook a comparative analysis of three attachment ventilation techniques: vertical wall-based attachment ventilation (WAV), square column-based attachment ventilation (SAV), and circular columnbased attachment ventilation (CAV). Through a combination of experiments and simulations, they scrutinized airow distribution characteristics.…”

Section: Introductionmentioning

confidence: 99%

CFD Validation of Wall Laws in K-ω SST Model for Adverse Pressure Gradient-Free Downward Flow

Belhadad,

Kanna,

El Rhafiki

et al. 2023

E3S Web of Conf.

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This study introduces a validation investigation employing Computational Fluid Dynamics (CFD) to assess the utilization of the Consistent Wall Law (CWL) in tandem with the K-Shear Stress Transport (SST) turbulence model, specifically in scenarios characterized by downward flow without adverse pressure gradients. The precise prediction of turbulent flows near walls is of paramount significance in the realm of engineering applications. The CWL is meticulously designed to enhance the precision of near-wall turbulence modeling by ensuring a harmonious alignment between wall functions and the flow field. To gauge the performance of CWL in the challenging context of downward flows marked by adverse pressure gradients, we conducted numerical simulations using a commercial CFD solver. The results reveal a substantial improvement in agreement with experimental data, particularly in critical near-wall regions. CWL effectively showcases its prowess in managing adverse pressure gradients and offering precise predictions for wall-related parameters. Moreover, we executed a sensitivity analysis to explore the durability of CWL across various parameter variations, confirming its effectiveness and trustworthiness. This research significantly contributes to a more profound comprehension of turbulence modeling, thereby facilitating the generation of more accurate predictions in intricate flow scenarios that are pertinent to engineering applications.

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“…The CCAV mode mainly aims to eliminate the cooling/heating load in the occupied zone, and the air supply volume is lower than that of the mixing ventilation, which reduces the energy consumption of the air-conditioning system operation. The airflow is attached to the column surface and flows downward, showing the phenomenon of radial radiation diffusion along the circumference of 360° in the horizontal air reservoir region [8][9][10][11]. However, the utilization of CCAV in large spaces remains a significant challenge.…”

Section: Introductionmentioning

confidence: 99%

Column-Attached Airflow Fields Created by Multi-slot in Single Ring

Wang

Han

et al. 2022

E3S Web Conf.

Self Cite

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Researchers have shown increasing interest in attachment ventilation due to its high ventilation efficiency and good thermal comfort. To meet the ventilation performance and engineering design challenges of Circular Column Attached Ventilation (CCAV) mode due to low ventilation rates, large-diameter cylinders, and installation too high at the top of large spaces. This paper proposes a novel ventilation mode known as Column-attached ventilation with Multi-slot in Single Ring (MCAV). Through measurement of air velocity and computational fluid dynamics simulation, the air distribution characteristics of the MCAV were studied. The findings show that MCAV and CCAV have similar trends of maximum velocity decay in the vertical attachment region. The MCAV has a 10.48% higher average value of dimensionless axial velocity in the horizontal air reservoir region than the CCAV. Besides, the flow pattern envelope surface and the velocity non-uniform coefficient were introduced to verify ventilation performance. The current study helps understand a new air distribution and is used as a reference for Attachment Ventilation design.

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Comparative studies on isothermal attachment ventilation based on vertical walls, square and circular columns

Cited by 18 publications

References 25 publications

Numerical Study of Air Distribution and Thermal Environment in Attached Ventilation Mode in the Generator Layer of a Hydropower Station

Numerical Study of Air Distribution and Thermal Environment in Attached Ventilation Mode in the Generator Layer of a Hydropower Station

CFD Validation of Wall Laws in K-ω SST Model for Adverse Pressure Gradient-Free Downward Flow

Column-Attached Airflow Fields Created by Multi-slot in Single Ring

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