Extended Coanda Effect and attachment ventilation

Li, Angui

doi:10.1177/1420326x19833850

Cited by 46 publications

(10 citation statements)

References 7 publications

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“…To the best of the author's knowledge, ventilation systems that rely on CEH have not been proposed to date, despite the fact that the Coanda effect is a well-known phenomenon that is widely used in ventilator design. The occurrence of the Coanda effect in ventilation has been discussed by [95][96][97]. Li [6] demonstrated that attachment ventilation based on the Coanda effect decreases the flow rate of fresh air by 20% and chiller capacity by 22%.…”

Section: Coanda Effect Hysteresis In Ventilationmentioning

confidence: 99%

The Applicability of Coanda Effect Hysteresis for Designing Unsteady Ventilation Systems

Skotnicka-Siepsiak

2020

Energies

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Energy-saving ventilation systems are designed to improve the energy efficiency of buildings. Low energy efficiency in buildings poses a considerable problem that needs to be addressed. Mechanical ventilation with heat recovery has gained increased popularity in recent years. Mechanical ventilation has numerous advantages, including easy adjustment and control, high indoor air quality and elimination of indoor pollutants. Mixing ventilation is the most popular type of mechanical ventilation, in particular in residential buildings. Unsteady ventilation is a type of mixing ventilation that involves stronger mixing effects and smaller vertical temperature gradients to improve indoor air quality (IAQ) and minimize energy consumption. This study examines the possibility of controlling and modifying Coanda effect hysteresis (CEH) to generate unsteady flow and simulate the conditions of unsteady mixing ventilation. The experiment was performed on a self-designed test bench at the University of Warmia and Mazury in Olsztyn. It demonstrated that an auxiliary nozzle can be applied at the diffuser outlet to control CEH and the angles at which the air jet becomes attached to and separated from the flat plate positioned directly behind the nozzle. The study proposes an innovative mixing ventilation system that relies on CEH. The potential of the discussed concept has not been recognized or deployed in practice to date. This is the first study to confirm that an auxiliary nozzle by the diffuser outlet can be operated in both injection and suction mode to control CEH. In the future, the results can be used to design a new type of nozzles for unsteady ventilation systems that are based on CEH control.

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Section: Coanda Effect Hysteresis In Ventilationmentioning

confidence: 99%

The Applicability of Coanda Effect Hysteresis for Designing Unsteady Ventilation Systems

Skotnicka-Siepsiak

2020

Energies

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“…As axis velocity attenuation is the key to the whole flow field. This work collects the experimental data from the research team’s previous wall-based attachment ventilation studies [35] , [37] , [41] , [50] and semi-empirical formulas from the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) [26] , Topp and Nielsen [51] , Yu et al [52] , and Rajaratnam [53] to validate the numerical model, as shown in Fig. 2 .…”

Section: Methodsmentioning

confidence: 99%

“…An air jet with high momentum can be maintained by the air jet attaching to the wall and reaching the occupied zone with acceptable air velocity via imping. The background mechanism of this concept is the Extended Coanda Effect (Coanda–Li effect) [27] , [34] , firstly proposed by Li, which is the tendency of a fluid jet to continually attach to a complex of convex and concave surfaces after impinging [35] .…”

Section: Introductionmentioning

confidence: 99%

Adaptive Wall-Based Attachment Ventilation: A Comparative Study on Its Effectiveness in Airborne Infection Isolation Rooms with Negative Pressure

Zhang

Han

et al. 2022

Engineering

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“…The velocity profile of the plume was measured at a height of 20 mm above the radiator and was already varying substantially along the width of the radiator, likely due to the combination of sudden expansion of the flow cross-section and the Coandă effect [12]. Instead, a constant inlet velocity value was used in the simulations.…”

Section: Reference Casementioning

confidence: 99%

Assessment of downward draught in high-glazing facades in cold climates – experimental and CFD study into draught control with a 21-type radiator

2021

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This paper investigates the interaction of a radiator’s thermal plume and downdraught of cold glazed surfaces. Draughts in working areas are one of the most common thermal comfort complaints in modern buildings. A typical solution for dealing with these draughts is positioning the heat emitters such as radiators or convectors under the windows. However, with thermally efficient envelopes, the internal loads compromise a relatively high fraction of the heating demand and the emitters are working under partial loads in modern buildings. This study comprises two parts: an experimental phase in the EN442 standardized test chamber with a 21-type radiator, and a CFD simulation phase, where the model is validated and applied under an expanded set of boundary conditions. The expanded simulation set results provide preliminary insight into sizing and design. More specifically, the thermal plume can be parametrised with a velocity and temperature value along with the room air and glazing temperatures for a broader analysis and assessment of the risk of draught.

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Extended Coanda Effect and attachment ventilation

Cited by 46 publications

References 7 publications

The Applicability of Coanda Effect Hysteresis for Designing Unsteady Ventilation Systems

The Applicability of Coanda Effect Hysteresis for Designing Unsteady Ventilation Systems

Adaptive Wall-Based Attachment Ventilation: A Comparative Study on Its Effectiveness in Airborne Infection Isolation Rooms with Negative Pressure

Assessment of downward draught in high-glazing facades in cold climates – experimental and CFD study into draught control with a 21-type radiator

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