Large eddy simulation of swirling jet in a bluff-body burner

Fujimoto, Yohei; Inokuchi, Yuzo; Yamasaki, Nobuhiko

doi:10.1007/s11630-005-0036-9

Cited by 6 publications

(4 citation statements)

References 9 publications

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“…One method is via a geometrical specification of a static, swirling device that consists of helicoidal surfaces, and another is a mathematical description of a swirling BC that reproduces the flow field. It has been reported in the literature and confirmed by this research that if a CFD code does not have a swirl boundary option, it is customary to develop the geometry for a swirl device and then mesh it [Duwig et al 2005;Fujimoto, Inokuchi, and Yamasaki, 2005;Garcia-Villalba, Frohlich, and Rodi, 2005;Rodriguez and El-Genk, 2008a and b;Rodriguez and El-Genk, 2008a, b, c However, deciding on a particular swirl angle a priori for the swirling device, and then meshing its geometry, is computationally-intensive and time consuming, not to mention that it is a tedious, error-prone, and expensive process. Furthermore, it is a challenge to investigate many swirl angles and keep track of all the meshes, which is the case for this research.…”

Section: Helicoid Swirl Modelingsupporting

confidence: 65%

“…The swirling jet subject matter is quite rich, and there are thousands of swirling jet papers in the literature as of 2011. Cziesla et al, 2001;Schluter, 2001;Garcia-Villalba, Frohlich, and Rodi, 2004;Wang and Bai, 2004;Duwig et al, 2005;Fujimoto, Inokuchi, and Yamasaki, 2005;Garcia-Villalba, Frohlich, and Rodi, 2005;Garcia-Villalba, 2006;Afgan, 2007;Muller and Kleiser, 2007;Stein, 2009;Zemtsop et al, 2009].…”

Section: Swirling Jets For Mitigation Of Hot Spots and Thermal Stratifimentioning

confidence: 99%

“…Whereas the RANS RSMs are designed to include non-isotropic effects, they had mixed results in the literature [Gibson and Younis, 1986;Hogg and Leschziner, 1989;Lai, 1995;Larocque, 2004;Krishna and Ganesan, 2005;Johnson, 2006;El-Behery and Hamed, 2009;Laurien, Lavante, and Wang, 2010;Valera-Medina et al, 2010] weak to strong S, with favorable comparisons to experimental data [Kim and Menon, 1999;Kravchenko and Moin, 2000;Cziesla et al, 2001;Schluter, 2001;Apte et al, 2003;Garcia-Villalba, Frohlich, and Rodi, 2004;Wang and Bai, 2004;Moet et al, 2004;Duwig et al, 2005;Garcia-Villalba, Frohlich, and Rodi, 2005;Lu et al, 2005;Fujimoto and Yamasaki, 2006;Garcia-Villalba and Frohlich, 2006;Gyllenram, Nilsson, and Davidson, 2006;Afgan, 2007;Bonaldo, 2007;Jagus et al, 2008;Muller and Kleiser, 2008;Rodriguez and El-Genk, 2008a, b, c, and d;Denev, Frohlich, and Bockhorn, 2009;Dinesh and Kirkpatrick, 2009;El-Behery and Hamed, 2009;Iaccarino and Constantine, 2009;Naughton et al, 2009;Stein, 2009;Uddin et al, 2009;Zemtsop et al, 2009;Doolan, 2010; and b; Rodriguez and ...…”

Section: Rementioning

confidence: 99%

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Swirling jets for the mitigation of hot spots and thermal stratification in the VHTR lower plenum.

Rodríguez¹

2011

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The literature indicates that a prismatic-core very high temperature reactor can experience thermal stratification and hot spot issues in the lower plenum (LP). This research hypothesizes that the complex thermalhydraulic phenomena in the LP requires a sophisticated computational fluid dynamics (CFD) code with state-of-the-art turbulence models and advanced swirling jet technology to mitigate the two issues. The primary research goals were to increase the heat transfer and mixing capacity of swirling jets, extend swirling jet theory, and to apply those advancements for the mitigation of the thermalhydraulic issues. First, it was demonstrated that the Fuego CFD code successfully modeled a set of key LP thermalhydraulic phenomena. Thereafter, a helicoid vortex swirl model was developed to investigate the impact of the swirl number (S) on mixing and heat transfer. The development of azimuthal and axial velocities that are solely functions of S permitted the analysis of the central recirculation zone's (CRZ) impact on the LP flow field. At this point, several characteristics were found in common between the helicoid vortex and other axisymmetric, Newtonian, incompressible vortices found in the literature. This observation resulted in a more fundamental understanding of how vortices behave, and which traits can be exploited for the purpose of maximizing heat transfer and mixing. Because the CRZ is a strong function of the azimuthal and axial velocities, shaping those velocity profiles had a substantial impact. Eventually, this led to the discovery that vortices may be expressed as alternating series that expand geometrically with odd exponents. This helped corroborate that the 15 axisymmetric vortices discussed in this research are part of a vortex family with seven common traits. This also led to the development of new vortices that are based on one or two series terms that satisfy the Navier-Stokes equations and conservation of mass. In addition, the impact of Reynolds number and swirl decay were explored in order to further quantify their impact. Finally, the above theories and modeling insights were applied towards a comprehensive set of LP calculations that showed that the swirling jets mitigated the entrainment and hot spot issues, while resulting in a reasonable pressure drop. Contents

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Section: Helicoid Swirl Modelingsupporting

confidence: 65%

Section: Swirling Jets For Mitigation Of Hot Spots and Thermal Stratifimentioning

confidence: 99%

Section: Rementioning

confidence: 99%

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Swirling jets for the mitigation of hot spots and thermal stratification in the VHTR lower plenum.

Rodríguez¹

2011

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“…Numerical study on the flow that involves an annular swirling jet and a bluff-body has been performed by Fujimoto and Yamasaki [12]. In their study, they performed a large eddy simulation of an unconfined swirling flow of air surrounding a bluff-body having a central jet of air.…”

Section: Introductionmentioning

confidence: 99%

A preliminary numerical study of a swirling jet behind a circular disc

Toh

Huang

Chern

2008

Proceedings of the Institution of Mechanical Engineers, Part C:

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The three-dimensional flow fields behind a circular disc produced by an annular swirling jet alone and by an annular swirling jet with a central jet issuing from the disc centre are studied by solving the three-dimensional incompressible Navier—Stokes equations numerically using the solution algorithm of Hirt et al. ( Los Alamos Scientific Lab. Rept. LA-5852 (1970)). The swirl number and the Reynolds number based on the disc diameter and the volumetric mean axial velocity of the annular swirling jet are S=0.194 and Re=656, respectively. The convective and diffusive terms in the governing equations are discretized using the second-order central difference scheme. The resulting discretized equations are advanced in time using the second-order Runge—Kutta scheme. The simulation shows that the flow field behind the circular disc exhibit periodic oscillating behaviour, with the second case having a higher frequency due to the presence of the central jet. The mechanism responsible for this oscillating behaviour is identified and discussed. An analysis of the mean velocity fields in the mid-plane shows the existence of a stagnation point on the axis of symmetry in the first case and two saddle points off the axis of symmetry in the second case.

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