Direct numerical simulation of turbulent concentric annular pipe flow

Chung, Seo Yoon; Rhee, Gwang Hoon; Sung, Hyung Jin

doi:10.1016/s0142-727x(02)00140-6

Cited by 101 publications

(51 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…In the DNS of Chung [18] the profile on the inner wall appears to be sensibly different from the law of the wall w + = 2.5 ln y + + 5.5 . The introduction of an internal boundary layer introduces features of external flows near the inner cylinder.…”

Section: Case Amentioning

confidence: 91%

“…Eccentricity influences the velocity profile, and for an eccentricity bigger than zero the velocity does not generally respect the law of the wall everywhere in the cross section [17]. Experimental data and calculation results related to the two of the layouts can be found in Nouri [17] and Chung [18]. There are two main effects acting in eccentric channels:…”

Section: Rationalementioning

confidence: 99%

See 1 more Smart Citation

Anisotropic Turbulence and Coherent Structures in Eccentric Annular Channels

Merzari

Ninokata

2008

Flow Turbulence Combust

View full text Add to dashboard Cite

Eccentric annular pipe flows represent an ideal model for investigating inhomogeneous turbulent shear flows, where conditions of turbulence production and transport vary significantly within the cross-section. Moreover recent works have proven that in geometries characterized by the presence of a narrow gap, large-scale coherent structures are present. The eccentric annular channel represents, in the opinion of the present authors, the prototype of these geometries. The aim of the present work is to verify the capability of a numerical methodology to fully reproduce the main features of the flow field in this geometry, to verify and characterize the presence of large-scale coherent structures, to examine their behavior at different Reynolds numbers and eccentricities and to analyze the anisotropy associated to these structures. The numerical approach is based upon LES, boundary fitted coordinates and a fractional step algorithm. A dynamic Sub Grid Scale (SGS) model suited for this numerical environment has been implemented and tested. An additional interest of this work is therefore in the approach employed itself, considering it as a step into the development of an effective LES methodology for flows in complex channel geometries. Agreement with previous experimental and DNS results has been found good overall for the streamwise velocity, shear stress and the rms of the velocity components. The instantaneous flow field presented large-scale coherent structures in the streamwise direction at low Reynolds numbers, while these are absent or less dominant at higher Reynolds and low eccentricity. After Reynolds averaging is performed over a long integration time the existence of secondary flows in the cross session is proven. Their shape is found to be constant over the Reynolds range surveyed, and dependent on the geometric parameters. The effect of secondary flows on anisotropy is studied over an extensive Reynolds range through invariant analysis. Additional insight on the mechanics of turbulence in this geometry is obtained.

show abstract

Section: Case Amentioning

confidence: 91%

Section: Rationalementioning

confidence: 99%

Anisotropic Turbulence and Coherent Structures in Eccentric Annular Channels

Merzari

Ninokata

2008

Flow Turbulence Combust

View full text Add to dashboard Cite

show abstract

“…However, the addition of a bulk-tosurface viscosity ratio term alone does not accurately predict this behavior. The functional form of the thermal boundary layer within the fluid has been extensively studied [14][15][16][17][18][19][20][21][22]. The studies indicate a dependence of the temperature boundary layer on the heat flux.…”

Section: Effect Of Heat Fluxmentioning

confidence: 99%

Heat transfer behavior of molten nitrate salt

Das

Clark

Teigen

et al. 2016

AIP Conference Proceedings

View full text Add to dashboard Cite

Abstract. The usage of molten nitrate salt as heat transfer fluid and thermal storage medium decouples the generation of electricity from the variable nature of the solar resource, allowing CSP plants to avoid curtailment and match production with demand. This however brings some unique challenges for the design of the molten salt central receiver (MSCR). An aspect critical to the use of molten nitrate (60wt%/40wt% -NaNO 3 /KNO 3 ) salt as heat transfer fluid in the MSCR is to understand its heat transfer behavior. Alstom collaborated with the University of Wisconsin to conduct a series of experiments and experimentally determined the heat transfer coefficients of molten nitrate salt up to high Reynolds number (Re > 2.0E5) and heat flux (q″ > 1000 kW/m 2 ), conditions heretofore not reported in the literature. A cartridge heater instrumented with thermocouples was installed inside a stainless steel pipe to form an annular test section. The test section was installed in the molten salt flow loop at the University of Wisconsin facility, and operated over a range of test conditions to determine heat transfer data that covered the expected operating regime of a practical molten salt receiver. Heat transfer data were compared to widely accepted correlations found in heat transfer literature, including that of Gnielinski. At lower Reynolds number conditions, the results from this work concurred with the molten salt heat transfer data reported in literature and followed the aforementioned correlations. However, in the region of interest for practical receiver design, the correlations did not accurately model the experimentally determined heat transfer data. Two major effects were observed: (i) all other factors remaining constant, the Nusselt numbers gradually plateaued at higher Reynolds number; and (ii) at higher Reynolds number a positive interaction of heat flux on Nusselt number was noted. These effects are definitely not modeled by the existing correlations. In this paper a new Nusselt number correlation is shown to accurately model the experimental data. A theory to explain the heat transfer trends at higher Reynolds number and heat flux is proposed. Finally, the impact of these results on receiver design is discussed, with comparison between correlations available from literature and that proposed in this study.

show abstract

“…Since CFD is powerful, it spans a wide range of industrial and non-industrial applications, and an example of these applications is the flow through an annulus pipe. "[a]nnular pipe flow is important in engineering applications such as heat exchangers, gas-cooled nuclear reactors and drilling operations in the oil and gas industry" [4]. They studied a turbulent concentric annular pipe flow for two radius ratios (R1/R2=0.1 and 0.5), by using the direct numerical simulation.…”

Section: Computational Fluid Dynamics (Cfd)mentioning

confidence: 99%

“…However, Rehme (1974) remarked that the position of zero shear stress is closer to the inner wall than maximum velocity. An LDV experiment in concentric annuli was conducted by Nouri et al (1993) and Escudier et al (1995) [4].…”

Section: Computational Fluid Dynamics (Cfd)mentioning

confidence: 99%

The influence of the tangential velocity of inner rotating wall on axial velocity profile of flow through vertical annular pipe with rotating inner surface

Sharf

Jawan

Almabsout

2014

EPJ Web of Conferences

View full text Add to dashboard Cite

Abstract. In the oil and gas industries, understanding the behaviour of a flow through an annulus gap in a vertical position, whose outer wall is stationary whilst the inner wall rotates, is a significantly important issue in drilling wells. The main emphasis is placed on experimental (using an available rig) and computational (employing CFD software) investigations into the effects of the rotation speed of the inner pipe on the axial velocity profiles. The measured axial velocity profiles, in the cases of low axial flow, show that the axial velocity is influenced by the rotation speed of the inner pipe in the region of almost 33% of the annulus near the inner pipe, and influenced inversely in the rest of the annulus. The position of the maximum axial velocity is shifted from the centre to be nearer the inner pipe, by increasing the rotation speed. However, in the case of higher flow, as the rotation speed increases, the axial velocity is reduced and the position of the maximum axial velocity is skewed towards the centre of the annulus. There is a reduction of the swirl velocity corresponding to the rise of the volumetric flow rate.

show abstract

Direct numerical simulation of turbulent concentric annular pipe flow

Cited by 101 publications

References 21 publications

Anisotropic Turbulence and Coherent Structures in Eccentric Annular Channels

Anisotropic Turbulence and Coherent Structures in Eccentric Annular Channels

Heat transfer behavior of molten nitrate salt

The influence of the tangential velocity of inner rotating wall on axial velocity profile of flow through vertical annular pipe with rotating inner surface

Contact Info

Product

Resources

About