A comparison of three turbulence models for the prediction of parallel lobed jets in perforated panel optimization

Meslem, Amina; Dia, Aliou; Béghein, Claudine; Hassan, Mouhammad El; Năstase, Ilinca; Vialle, Pierre-Jean

doi:10.1016/j.buildenv.2011.04.037

Cited by 37 publications

(20 citation statements)

References 40 publications

(45 reference statements)

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“…8, a). This behavior is somewhat similar of that of twin jets [39][40][41]. The merging point MP is defined as the point on the central axis X= 0, where the centerline velocity WC = 0 (Fig.…”

Section: Airflow Pattern Analysissupporting

confidence: 57%

Passive control strategy for mixing ventilation in heating mode using lobed inserts

Bragança

Sodjavi

Meslem

et al. 2016

Energy and Buildings

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Research Highlights: Flow pattern and thermal comfort are analyzed in a room under mixing ventilation > A vertical hot jet is generated by a conventional ceiling multi-cone diffuser > The effect of inserted lobes into the conventional diffuser is analyzed > Significant improvement of thermal comfort is achieved due to jet induction increase > It was not observed a significant increase in pressure drop and noise ABSTRACTThe main purpose of ventilation systems is to satisfy the need of occupants in terms of thermal comfort and air quality. In the case of mixing ventilation, based on the use of jets from one or from multiple diffusers placed in the room, the fresh air and the thermal loads should be distributed in the entire occupied zone. Therefore, the design of the diffusers must aim, beyond aesthetic aspect, the ability to provide a good mixing between the jet and the ambient air. Enhancement of jet induction by means of lobed inserts into a diffuser, was recently proposedin an European patent as a promising and low-cost solution for improving the performance of HVAC systems. In this paper, an experimental investigation on jet characteristics and thermal comfort generated by a classical multi-cone ceiling-mounted diffuser is proposed. Its performance is compared with the same diffuser equipped with lobed inserts. A simplified heated manikin simulates the presence of a human body in the test room. Airflow pattern from the diffuser and its interaction with the manikin were analyzed with whole-field PIV technique.Thermal comfort was analyzed based on traditional pointwise measuring probes and on the standard ISO 7730. It is revealed that the thermal comfort was significantly improved using the lobed diffuser compared to the conventional one, without increase of pressure drop and sound pressure levels.

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Section: Airflow Pattern Analysissupporting

confidence: 57%

Passive control strategy for mixing ventilation in heating mode using lobed inserts

Bragança

Sodjavi

Meslem

et al. 2016

Energy and Buildings

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“…In another study, it was reported that an accuracy of 5% to 10% could be achieved for the room airflow measurements using the two-component PIV technique [16]. In an investigation of a turbulent twin cross-shaped jet on a perforated panel diffuser [51], the maximal displacement error for the 2D PIV measurements was estimated to be 1.4%. For the stereoscopic PIV results, the maximal displacement error was equal to 0.8, 1.7 and 2.2% for the longitudinal, vertical and transversal directions respectively.…”

Section: Discussionmentioning

confidence: 98%

“…The results showed that cross-shaped jets performed much better than the circular reference jets as a method of passive control of air diffusion systems for buildings. They also used PIV to measure the flow field of a turbulent twin cross-shaped jet on a perforated panel diffuser [51]. The experimental results were used to validate various numerical models.…”

Section: Ventilation Devicesmentioning

confidence: 99%

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Particle image velocimetry measurement of indoor airflow field: A review of the technologies and applications

Cao

Liu

Jiang

et al. 2014

Energy and Buildings

130

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Quantifying the airflow field in building room or vehicle cabin indoor space is crucial for creating a thermal comfortable and healthy indoor environment. Airflow field measurement can provide quantitative information of indoor air distribution and local air velocity around occupants or passengers, which has strong relationship with the ventilation effectiveness, the pollutant transportation and the energy conservation in a building or a vehicle. However, the airflow field in indoor environment is normally characterized by high turbulent level and unsteady due to relatively low air velocity from the diffuser, thermal plume of heat source and unsteady perturbation of occupants' behavior. Generally, it is very difficult to conduct accurate and detailed measurement of such a complex turbulent flow field with point-wise anemometry.

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“…Svensson, Rohdin, Moshfegh and Tummers [32] suggested that this problem may be overcome by using an adjusted combined point, defined as the point where the minimum velocity between two jets does not fall below 90% of the maximum velocity for the jet under consideration (U max,J ). The approach is somewhat similar to the method employed in [49], where a fixed velocity difference of 0.15 m/s, defined as the corrected combined point, is used to avoid uncertainties related to small fluctuations in the mean velocity profile.…”

Section: Adjusted Combined Pointsmentioning

confidence: 99%

A computational parametric study on the development of confluent round jet arrays

Svensson¹,

Rohdin²,

Moshfegh³

2015

European Journal of Mechanics - B/Fluids

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A comparison of three turbulence models for the prediction of parallel lobed jets in perforated panel optimization

Cited by 37 publications

References 40 publications

Passive control strategy for mixing ventilation in heating mode using lobed inserts

Passive control strategy for mixing ventilation in heating mode using lobed inserts

Particle image velocimetry measurement of indoor airflow field: A review of the technologies and applications

A computational parametric study on the development of confluent round jet arrays

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