Pressure loss reduction in hydrogen pipelines by surface restructuring

Peet, Yulia; Sagaut, Pierre; Charron, Yves

doi:10.1016/j.ijhydene.2009.08.035

Cited by 37 publications

(23 citation statements)

References 29 publications

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“…In the case of transitions between flat wall and riblets, it cancels out, or at least restricts, the net pressure force acting at the leading and trailing edges of the grooves. This choice of origin has been used in the channel flow simulations of Peet et al [48]. With the present riblet design, it leads to h y=0 = h 2 s tan( 30 • 2 ) ≈ 0.13 h rib .…”

Section: Virtual Origin Definitionmentioning

confidence: 93%

Riblet Flow Model Based on an Extended FIK Identity

Bannier

Garnier

Sagaut

2015

Flow Turbulence Combust

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International audienceLarge Eddy Simulations of zero-pressure-gradient turbulent boundary layers over riblets have been conducted. All along the controlled domain, riblets maintain a significant 11 % drag reduction with respect to the flat plate at the same R e τ (from 250 to 450). To compare the flows above riblets and a reference smooth wall, an appropriate vertical shift between the two surfaces is required. In the present study, the “vertical origin” is set using the identity of Fukagata, Iwamoto and Kasagi (FIK) in Phys. Fluids, vol. 14, 2002, L73. This identity, which provides a physically meaningful decomposition of the skin friction, has been extended to complex wall surfaces and constitutes the basis for the derivation of a new virtual origin. Using this FIK-based origin, it is shown that the complex interactions between the riblets and the near-wall turbulent structures can be taken into account by a simple shift of the two axes of the mean and turbulent velocity profiles. The appropriate upward shift Δu +, typical for drag reduction, is directly dependent on the skin friction on the riblets and on the reference smooth plate at the same R e τ

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Section: Virtual Origin Definitionmentioning

confidence: 93%

Riblet Flow Model Based on an Extended FIK Identity

Bannier

Garnier

Sagaut

2015

Flow Turbulence Combust

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“…5,6,11,14 However, a practical, cost-effective implementation has yet to be achieved, mostly hindered by the small optimal spacing required (about 15 µm in cruise-speed conditions) and stringent tolerances on the sharpness of the crests. More complex variants, such as sinusoidal riblets, were studied by Bannier, 4 Kramer et al, 21 and Peet et al, 27 but despite attempts to optimise the geometry, Bannier 4 showed that conventional (straight) riblets appear to be as effective within the uncertainty margins. a) s.ghebali14@imperial.ac.uk b) s.chernyshenko@imperial.ac.uk c) mike.leschziner@imperial.ac.uk…”

Section: Introductionmentioning

confidence: 99%

Can large-scale oblique undulations on a solid wall reduce the turbulent drag?

Chernyshenko

Leschziner

2017

Physics of Fluids

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Direct numerical simulations of fully developed turbulent channel flows with wavy walls are undertaken. The wavy walls, skewed with respect to the mean flow direction, are introduced as a means of emulating a Spatial Stokes Layer (SSL) induced by in-plane wall motion. The transverse shear strain above the wavy wall is shown to be similar to that of a SSL, thereby affecting the turbulent flow and leading to a reduction in the turbulent skin-friction drag. However, some important differences with respect to the SSL case are brought to light too. In particular, the phase variations of the turbulent properties are accentuated and, unlike in the SSL case, there is a region of increased turbulence production over a portion of the wall, above the leeward side of the wave, thus giving rise to a local increase in dissipation. The pressure- and friction-drag levels are carefully quantified for various flow configurations, exhibiting a combined maximum overall-drag reduction of about 0.6%. The friction-drag reduction is shown to behave approximately quadratically for small wave slopes and then linearly for higher slopes, whilst the pressure-drag penalty increases quadratically. The transverse shear-strain layer is shown to be approximately Reynolds-number independent when the wave geometry is scaled in wall units.

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“…According to Gim et al [8], one of the major tasks in transition to a hydrogen economy is to build a cost-effective infra-structure for the supply of hydrogen. In this scenario, pipelines have proven to be one of the most economical ways to transport hydrogen, especially for large demands, long distances, and with minimal energy loss if adequate pipes and initial pressures are selected [9,10]. According to Conte et al [11], the transport and distribution system of gaseous hydrogen might look like current natural gas pipelines.…”

Section: Introductionmentioning

confidence: 99%