Mixing with multiple circular turbulent jets

Moawad, Ahmed K.; Rajaratnam, N.; Stanley, Stephen

doi:10.1080/00221680109499817

Cited by 12 publications

(6 citation statements)

References 3 publications

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“…Above and beyond empirical methods applied to analyze experimental results regarding multiple jet mixing (Moawad et al, 2001), the integral method is commonly used to handle the merging behavior of multiple buoyant jets in either stagnant or flowing environments (Briggs, 1975;Yannopoulos, 1996;Papps and Wood, 1997;Davidson et al, 2002). The companion papers by Yannopoulos and Noutsopoulos (2006a, b) describe the development and the experimental verification of two integral models based on two approaches: (a) Entrainment Restriction Approach (ERA), and (b) Superposition Method (SM).…”

Section: Introductionmentioning

confidence: 98%

Round turbulent buoyant jets discharged vertically upwards forming a regular polygon

Bloutsos

Yannopoulos

2009

Journal of Hydraulic Research

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Round turbulent buoyant jets discharged vertically upwards forming a regular polygon Jets ronds flottants turbulents émis verticalement vers le haut en formant un polygone régulier ARISTEIDIS A. BLOUTSOS, Postgraduate student, ABSTRACT The simplified partial differential equations of momentum and tracer for the mean motion are integrated on the reduced cross-sectional area within the field of one buoyant jet from a group issued vertically upwards from a rosette-type riser. The solutions yield the dimensionless centerline axial velocities and concentrations. Mathematically, the one-jet field is separated from the entire group by employing the Entrainment Restriction Approach (ERA) applicable in interacting buoyant jets with symmetry planes. ERA was herein improved by incorporating the Second Order Approach (SOA). Interaction effects are highlighted by normalizing the mean-flow properties. The role of buoyancy on merging is introduced by a dynamic parameter, which combines proximity effects with buoyancy, thus termed dynamic proximity number. In addition, the distributions for mean dilution, kinetic energy flux and local Richardson number are also predicted, discussed, and compared with data reported in the literature. Findings may be useful for design purposes and environmental impact assessment. RÉSUMÉLes équations aux dérivées partielles simplifiées de la quantité de mouvement et du traceur pour l'écoulement moyen sont intégrées sur la section transversale réduite d'un seul jet flottant regroupant les émissions verticales vers le haut d'une colonne montante de type rosette. Les solutions fournissent les vitesses et des concentrations axiales sans dimensions le long de la ligne centrale. Mathématiquement, le champ du jet unique est séparé du groupe entier en utilisant l'Approche de Restriction d'Entraînement (ERA) applicable aux jets flottants interactifs avec plans de symétrie. La méthode ERA a été ici améliorée en y incorporant l'Approche du Second Ordre (SOA). Les effets d'interaction sont mis en relief par la normalisation des propriétés de l'écoulement moyen. Le rôle de la flottabilité sur le fusionnement est introduit par un paramètre dynamique, qui combine les effets de proximité et de flottabilité, nommé nombre dynamique de proximité. En outre, les distributions de la dilution moyenne, du flux d'énergie cinétique et du nombre de Richardson local sont également calculées, discutées, et comparées aux données rapportées dans la littérature. Les résultats peuvent être utiles pour des objectifs de conception et l'évaluation de l'impact environnemental. assistance in the design and environmental impact assessment of such a system. The operation of these systems and the possible measures taken to minimize probable environmental impacts may also be evaluated by employing computer models in conjunction with field observations. Due to buoyant-jet merging, the flow and mixing field is generally complicated and difficult to resolve. Regarding ocean outfalls using diffusers with rosettetype risers including those with...

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Section: Introductionmentioning

confidence: 98%

Round turbulent buoyant jets discharged vertically upwards forming a regular polygon

Bloutsos

Yannopoulos

2009

Journal of Hydraulic Research

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“…According to Braikia et al [12], optimizing parameters such as diffuser geometry, initial velocity, swirl number, gap between jets, blown jets number, and the central jet can significantly improve the quality of the cooling air mixture. Moawad et al [13] achieved a study of multiple jets efficiency for the chemical mixing in an open channel. More explicitly, they considered two jet arrangements whose ratio of the velocity of the jets to that of the cross-flow varies from 8 to 16.…”

Section: Introductionmentioning

confidence: 99%

An experimental investigation of interacting swirling multiple jets

et al. 2020

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This article deals with the experimental investigation of multiple interacting jets, which may be interested in many engineering applications such as design of a ventilation supply device. The main objective of this study is to achieve the best configuration for use in ventilation applications. To achieve this, several parameters have been considered and discussed such as the imbalance in temperature and diffuser orifices position with relative imbalance in flow rate between central and peripheral jets. Flow rate has been adjusted at Reynolds numbers, ranging from 10 4 to 3•10 4. The present study is carried out under uniform heat flux condition for each diffuser, and air is used as a working fluid. Experiences concerning the fusion of several jets show that the resulting jet is clearly more homogenized under the influence of the central swirling jet. Highlights of such an investigation show that, if the relative position of the central jet is higher, the radial spreading of the resultant jet is more important when all jets are in the same plane. This spreading is also improved compared to the case where the relative position of the peripheral jets is higher, thereby allowing to process a large volume of air. In addition, it becomes attractive to operate, especially when we aim premises homogenization.

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“…The flames from multiple jets aligned have used in many industrial installation. Several studies have been published on the dynamic properties of non-reacting multiple jets [6,13,14,17,20]. Lee et al [7] have studied the geometry parameters of diffusion flames and giving a number of variables such as the number of jets and the distance between the jets.…”

Section: Introductionmentioning

confidence: 99%

A New Combustion Method in a Burner with Three Separate Jets

Mergheni¹,

Belhajbrahim²,

Boushaki³

et al. 2020

Numerical and Experimental Studies on Combustion Engines and Vehicles

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Oxy-flames from burners with separated jets present attractive perspectives because the separation of reactants generates a better thermal efficiency and reduction of pollutant emissions. The principal idea is to confine the fuel jet by oxygen jets to favor the mixing in order to improve the flame stability. This chapter concerns the effect of equivalence ratio on characteristics of a non-premixed oxy-methane flame from a burner with separated jets. The burner of 25 kW power is composed with three aligned jets, one central methane jet surrounded by two oxygen jets. The numerical simulation is carried out using Reynolds Average Navier-Stokes (RANS) technique with k-ε as a turbulence closure model. The eddy dissipation model is applied to take into account the turbulence-reaction interactions. The study is performed with different global equivalence ratios (0.7, 0.8 and 1). The validation of the numerical tools is done by comparison with experimental data of the stoichiometric regime (Ф = 1). The two lean regimes of Ф = 0.7 and 0.8 are investigated only by calculations. The velocity fields with different equivalence ratio are presented. It yields to increase of longitudinal and transverse velocity, promotes the fluctuation in interaction zone between fuel and oxygen also a better mixing quality and a decrease of the size of the recirculation zone.

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Mixing with multiple circular turbulent jets

Cited by 12 publications

References 3 publications

Round turbulent buoyant jets discharged vertically upwards forming a regular polygon

Round turbulent buoyant jets discharged vertically upwards forming a regular polygon

An experimental investigation of interacting swirling multiple jets

A New Combustion Method in a Burner with Three Separate Jets

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