Experimental study on the flow characteristics of air curtains at building entrances

Goubran, Sherif; Qi, Dahai; Saleh, Wael; Wang, Liangzhu; Zmeureanu, Radu

doi:10.1016/j.buildenv.2016.05.037

Cited by 62 publications

(46 citation statements)

References 8 publications

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“…However, there is no systematic approach to the contaminant aerodynamic sealing in the transition between the optimum condition and the 'inflow breakthrough condition'. The studies on the application of air curtains have been based on experiments [13,[26][27][28][29], on CFD models [23,29,30], and on semi-analytical models [12,31].…”

Section: (A) (B)mentioning

confidence: 99%

“…Goubran et al [13] present an experimental study to verify and further investigate the flow characteristics of the building entrances equipped with air curtains. In this study, the working fluid is the air and the nozzle thickness was 0.0635 m. Two different supply velocities were selected, namely: (1) the maximum supply speed of the unit is 13.75 m/s; and (2) a lower speed 9.1 m/s.…”

Section: (A) (B)mentioning

confidence: 99%

“…Hayes [8] developed the deflection modulus (Dm), which is indicative of the deflection of the air curtain jet and expresses the ratio of the outlet momentum to the transverse forces on the jet [12]. They defined [10] the operation condition where the air curtain jet reaches the floor as the 'optimum condition' and other operation conditions where the air curtain jet does not reach the floor as 'break-through condition', which can be further divided into the 'inflow breakthrough condition', where the air curtain flow is curved inward and does not reach the floor, and the 'outflow breakthrough condition', where the air curtain flow is curved outwards and does not reach the floor [13]. In our research, the ideal condition corresponds to the limit between the optimum condition and the inflow breakthrough condition, when having Figure 1 as reference ( Figure 1a), because in this condition, the contaminant mixed up in the jet flow is not released to the outside of the compartment.…”

Section: Introductionmentioning

confidence: 99%

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Experimental Study on the Aerodynamic Sealing of Air Curtains

Viegas

Oliveira

Aelenei

2018

Fluids

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Abstract:Controlling the air quality is of the utmost importance in today's buildings. Vertical air curtains are often used to separate two different climatic zones with a view to reduce heat transfer. In fact, this research work proposes an air curtain aimed to ensure a proper separation between two zones, a clean one and a contaminated one. The methodology of this research includes: (i) small-scale tests on water models to ensure that the contamination does not pass through the air curtain, and (ii) an analytical development integrating the main physical characteristics of plane jets. In the solution developed, the airflow is extracted from the contaminated compartment to reduce the curtain airflow rejected to the exterior of the compartment. In this research work, it was possible to determine the minimum exhaust flow necessary to ensure the aerodynamic sealing of the air curtain. This article addresses the methodology used to perform the small-scale water tests and the corresponding results.

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Section: (A) (B)mentioning

confidence: 99%

Section: (A) (B)mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Experimental Study on the Aerodynamic Sealing of Air Curtains

Viegas

Oliveira

Aelenei

2018

Fluids

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“…The aerodynamic sealing performance of vertical air curtains under isothermal and nonisothermal conditions where studied by Hayes and Stoecker. [12][13][14] Three operation conditions were defined 13,15,16 : (i) the 'optimum condition', which the air curtain jet reaches the floor, (ii) the 'inflow breakthrough condition', in which the air curtain flow is curved inwards and does not reach the floor, and (iii) the 'outflow breakthrough condition', in which the air curtain flow is curved outwards and does not reach the floor. Our research is developed in order to find the best practical conditions to avoid that the contaminant mixed up in the jet flow is not released to the exterior of the "contaminated" compartment.…”

Section: Introductionmentioning

confidence: 99%

Full-size experimental assessment of the aerodynamic sealing of air curtains for particulate matter

Viegas

Kaluzny²,

Durand³

et al. 2020

Building Services Engineering Research and Technology

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An air curtain is used to ensure an adequate separation between two compartments that is aimed to restrict, a clean one and a contaminated one. The air curtain performance is improved with the use of an air extraction from the “contaminated” compartment. The aerodynamic sealing of an optimized air curtain is assessed regarding particulate matter. The evaluation using visual assessment of the aerodynamic sealing using a cold smoke source is validated against PM 10 detection. It is shown that the air curtain presents a good aerodynamic sealing for the particulate of PM10 and PM2.5 classes and that the visual assessment method can lead to similar results. An equation was obtained with a view to be used to predict the level of aerodynamic sealing of the air curtain when the exhaust rate becomes too low. Another equation was obtained for predicting the average velocity through the door protected by the air curtain required to obtain an aerodynamic sealing, as a function of the jet parameters (nozzle average velocity and thickness). These test results prove that the air curtain, complemented with an air exhaust from the “contaminated compartment”, is suitable to provide an acceptable aerodynamic sealing for the particulate matter. Practical application: The findings of this research are applicable when it is necessary to retain the contamination due to particulate matter using a soft boundary, as air plane jets. This is applicable to medical care centres to reduce the possibility of contamination due to bacteria between different compartments or in pharmaceutical process units to avoid cross contamination among them.

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“…ACs are applied in many practical applications, for example, at entrances of buildings and refrigerated rooms to reduce heat losses (e.g. Wang and Zhong 2014;Goubran et al 2016;Gonçalves et al 2019;Yang et al 2019) and in laboratories or operating theatres (e.g. Nino et al 2011;Chen et al 2013;Zhai and Osborne 2013) to reduce contamination hazard.…”

Section: Introductionmentioning

confidence: 99%

Minimum momentum flux ratio required to prevent air curtain breakthrough in case of cross-curtain pressure gradients: CFD versus analytical equation

Khayrullina¹,

Hooff

Ruiz

et al. 2020

Build. Simul.

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This paper presents a numerical study on the required momentum flux ratio to prevent air curtain breakthrough in case of cross-curtain (i.e. cross-jet) pressure gradients. 2D steady Reynolds-averaged Navier-Stokes (RANS) CFD simulations with the RNG k-ε turbulence model are employed for jet Reynolds numbers ranging from 5,000 to 30,000. First, the computational model is validated based on particle image velocimetry (PIV) measurements. Second, the influence of several jet parameters on the separation efficiency is evaluated for a moderate cross-jet pressure difference of 10 Pa. These are the ratio of the jet discharge momentum flux to the jet cross-flow momentum flux (momentum flux ratio), the jet height-to-width ratio and the jet discharge angle. Finally, the minimum deflection modulus to prevent jet breakthrough and the corresponding momentum flux ratio by an analytical equation and by CFD are compared. The results show that, for the configuration under study: (1) jets with the smallest height-to-width ratios (β = 18) provide the highest separation efficiency; (2) inclined jets with discharge angles α0 = 5° and 10° provide slightly higher separation efficiency than straight jets (α0 = 0°) and jets with α0 = 20°; (3) the maximum modified separation efficiency is reached at lower momentum flux ratios for jets with smaller height-to-width ratios and for inclined jets; (4) the analytical and CFD values of the optimal momentum flux ratio differ with up to 31.2%. This study shows how the separation efficiency of air curtains can be improved by adjusting certain jet parameters.

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Experimental study on the flow characteristics of air curtains at building entrances

Cited by 62 publications

References 8 publications

Experimental Study on the Aerodynamic Sealing of Air Curtains

Experimental Study on the Aerodynamic Sealing of Air Curtains

Full-size experimental assessment of the aerodynamic sealing of air curtains for particulate matter

Minimum momentum flux ratio required to prevent air curtain breakthrough in case of cross-curtain pressure gradients: CFD versus analytical equation

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