Modelling of strongly swirling flows in a complex geometry using unstructured meshes

Wang, Junye; Priestman, G. H.; Tippetts, J. R.

doi:10.1108/09615530610702069

Cited by 30 publications

(16 citation statements)

References 19 publications

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“…As for convection terms, a well-known QUICK scheme was used to interpolate the face values of the different quantities from the cell-averaged values and second-order central difference was adopted for viscous terms. Regarding swirling flows, the primacy of using QUICK scheme was confirmed by previous studies [20]. The face values of pressure terms have been calculated using the Presto method.…”

Section: Numerical Considerationsupporting

confidence: 59%

Investigation on the Effects of Various Swirl Generators on Heat Transfer and Fluid Flow in Decaying Swirling Flows

Ahmadvand¹,

Najafi²,

Shahidinejad³

2010

Proceedings of the Institution of Mechanical Engineers, Part C:

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Influences of three typical vortex generators on flow pattern and ensuing heat transfer augmentation were investigated and compared at similar Re and swirl numbers inlet conditions. Studied swirlers such as propeller swirlers, jet-type swirlers, and rotating honeycombs were installed at the pipe inlet. Reynolds number ranges from 10000 to 30000. Swirlers were set on the swirl numbers 1.4, 0.89, and 0.52, which were obtained by propellers. This study has been carried out under uniform heat flux condition and air was employed as the working fluid. The obtained results provide the individual effects of each swirler configuration on mean flow and turbulence distribution as well as on enhancement of heat transfer. Considering S=1.4, jet-type swirlers pointed 133 per cent Nu enhancement compared to axial flow, whereas propellers and rotating honeycombs approached 105 per cent and 79 per cent, respectively. For S=0.89, relative treatment has been changed and propellers with 70 per cent Nu augmentation demonstrated tip-top performance behind of which other swirlers lined. By decreasing the swirl number, approximately closer heat performances were represented from all swirler configurations. Comparison of the results of various swirlers exhibited that Re and swirl numbers are not generally sufficient to determine the swirling flow characteristics and each swirler confirms an individual flow quality.

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Section: Numerical Considerationsupporting

confidence: 59%

Investigation on the Effects of Various Swirl Generators on Heat Transfer and Fluid Flow in Decaying Swirling Flows

Ahmadvand¹,

Najafi²,

Shahidinejad³

2010

Proceedings of the Institution of Mechanical Engineers, Part C:

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“…As mentioned above, existing literature on swirling flows mainly investigates free (non-impinging) jets where LES, RNG k-, SST k-ω and Reynolds stress models show varied agreement with experimental data depending on the level of swirl. Outside the scope of LES, RSM has generally been applied in strong swirling (non-impinging) flows [96][97][98]. However, RSM is also found to be incapable of resolving all the deficiencies of the two-equation models for simulating relatively weak (S ≤ 0.5) turbulent swirling flows [99][100][101].…”

Section: Baseline Non-swirling Impinging Jets: T-i and F-imentioning

confidence: 99%

The effect of inflow conditions on the development of non-swirling versus swirling impinging turbulent jets

2015

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“…By comparison little has been published on the simulation of flows through VXAs, some notable exceptions being Refs. [8][9][10]. To facilitate the objectives of this investigation, a series of experiments and simulations have been undertaken to understand better the physics of radial VXAs and their characteristic behavior.…”

Section: Introductionmentioning

confidence: 99%

Computational Fluid Dynamic Studies of Vortex Amplifier Design for the Nuclear Industry—II. Transient Conditions

Francis

Birch

Parker

2012

Journal of Fluids Engineering

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In this paper computational fluid dynamics (CFD) techniques have been used to investigate the effect of changes to the geometry of a vortex amplifier (VXA) in the context of glovebox operations in the nuclear industry. These investigations were required because of anomalous behavior identified when, for operational reasons, a long-established VXA design was reduced in scale. The study simulates the transient aspects of two effects: back-flow into the glovebox through the VXA supply ports, and the precessing vortex core in the amplifier outlet. A temporal convergence error study indicates that there is little to be gained from reducing the time step duration below 0.1 ms. Based upon this criterion, the results of the simulation show that the percentage imbalance in the domain was well below the required figure of 1%, and imbalances for momentum in all three axes were all below measurable values. Furthermore, there was no conclusive evidence of periodicity in the flow perturbations at the glovebox boundary, although good evidence of periodicity in the device itself and in the outlet pipe was seen. Under all conditions the modified geometry performed better than the control geometry with regard to aggregate reversed supply flow. The control geometry exhibited aggregate nonaxisymmetric supply port back-flow for almost all of the simulated period, unlike the alternative geometry for which the flow through the supply ports was positive, although still nonaxisymmetric, for most of the period. The simulations show how transient flow structures in the supply ports can cause flow to be reversed in individual ports, whereas aggregate flow through the device remains positive. Similar to the supply ports, flow through the outlet of the VXA under high swirl conditions is also nonaxisymmetric. A time-dependent reverse flow region was observed in both the outlet and the diffuser. It is possible that small vortices in the outlet, coupled with the larger vortex in the chamber, are responsible for the oscillations, which cause the shift in the axis of the precessing vortex core (and ultimately in the variations of mass flow in the individual supply ports). Field trials show that the modified geometry reduces the back-flow of oxygen into the glovebox by as much as 78%. At purge rates of 0.65 m 3 =h the modified geometry was found to be less effective, the rate of leakage from the VXA increasing by 16-20%. Despite this reduced performance, leakage from the modified geometry was still 63% less than the control geometry.

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Modelling of strongly swirling flows in a complex geometry using unstructured meshes

Cited by 30 publications

References 19 publications

Investigation on the Effects of Various Swirl Generators on Heat Transfer and Fluid Flow in Decaying Swirling Flows

Investigation on the Effects of Various Swirl Generators on Heat Transfer and Fluid Flow in Decaying Swirling Flows

The effect of inflow conditions on the development of non-swirling versus swirling impinging turbulent jets

Computational Fluid Dynamic Studies of Vortex Amplifier Design for the Nuclear Industry—II. Transient Conditions

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