Two-phase flow of solid hydrogen particles and liquid helium

Xu, Jian; Rouelle, A.; Smith, Kendra L.; Celik, D.; Hussaini, M. Y.; Sciver, S.W. Van

doi:10.1016/j.cryogenics.2004.02.008

Cited by 30 publications

(9 citation statements)

References 14 publications

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“…Analogous to thermodynamic temperature in a gas, granular temperature for solid phase can be defined as [20]: (7) hereis the mean square of fluctuation velocity of particles, c= u s − . The transport equation for granular temperature based on conservation of particles fluctuating energy is given by [21]: (8) The first term on the right-hand side of this equation represents rates of production of pseudo-thermal energy by shear; the second represents diffusive transport of pseudo-thermal energy. γ Θsi represents dissipation of pseudo-thermal energy through inelastic collisions, φ fsi denotes exchange of fluctuating energy between fluid and i th component of solid phase, D fsi is granular energy dissipation rate, K Θsi is granular conductivity.…”

Section: Constitutive Equation Of Solid Phasementioning

confidence: 99%

“…Recently, many researchers used a mixture model, a simplified form of the Eulerian approach, to predict concentration and velocity distributions as well as pressure drop of slurry flow [6][7][8]. Its computation is relatively inexpensive and it is straightforward to introduce a turbulence model into the mixture model [8]. However, the mixture model does not account for effects of particle-particle interaction which extensively occur at high solid loading, so it is reasonably accurate for slurries with moderate volumetric concentrations.…”

Section: Introductionmentioning

confidence: 99%

“…Those approaches though successful, have a draw back that it needs many experimental coefficients or empirical equations to enclose the governing equation. Recently, many researchers used a mixture model, a simplified form of the Eulerian approach, to predict concentration and velocity distributions as well as pressure drop of slurry flow [6][7][8]. Its computation is relatively inexpensive and it is straightforward to introduce a turbulence model into the mixture model [8].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

CFD simulation of coal-water slurry flowing in horizontal pipelines

Chen

Duan

et al. 2009

Korean J. Chem. Eng.

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An Eulerian multiphase approach based on kinetic theory of granular flow was used to simulate flow of coal-water slurries (CWS) in horizontal pipelines. The RNG k-ε turbulent model was incorporated in the governing equation to model turbulent two-phase flow with strong particle-particle interactions. In this model, the coal particles with bimodal distribution were considered as two solid-phase components, and the moment exchange between solid and liquid as well as that between solid and solid were accounted for. The model was firstly validated with pressure gradient and concentration profile data from the open literature, and then validated with pressure gradient data of the authors' experiments. The effects of influx velocity, total influx concentration and grain composition were numerically investigated, and the results have displayed some important slurry flow characteristics, such as constituent particle concentration distribution and velocity distribution as well as pressure gradients, which are very difficult to display in the experiments. The results suggest that both gravity difference between large and small particles and strong particleparticle interaction had significant effects on concentration distribution as well as velocity distribution.

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Section: Constitutive Equation Of Solid Phasementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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CFD simulation of coal-water slurry flowing in horizontal pipelines

Chen

Duan

et al. 2009

Korean J. Chem. Eng.

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“…There are commonly four popular approaches for numerically studying nanofluids: the single-phase model [6,7], the mixture multiphase model [8][9][10][11][12][13][14][15][16][17][18][19][20][21], the EulerianEulerian multiphase model [22][23][24][25][26][27] and the Euler-Lagrange multiphase model [28][29][30][31]. Although a variety of modified models that describe the heat transfer process in nanofluids is continually presented, thus far all modeling results are not very satisfactory: they all underestimate heat transfer coefficients when compared with experiment.…”

Section: Introductionmentioning

confidence: 99%

Numerical Investigation on the Turbulent Flow Characteristic of Nanofluids in a Horizontal Circular Tube

Wang¹,

Bai²,

Lv³

et al. 2014

Numerical Heat Transfer, Part A: Applications

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Turbulent flow characteristic of TiO 2 -water nanofluids inside a horizontal circular tube is studied numerically by single-phase model, mixture multiphase model and EulerianEulerian multiphase model. The flow characteristic is accounted from micro-flow aspect in order to reveal the mechanism of heat transfer enhancement in nanofluids. A new empirical correlation of nanoparticle viscosity has been proposed for multiphase models, which is much more precise than traditional empirical models. The presence of nanoparticles intensified local micro-flow and improved overall turbulence intensity significantly. The current study suggests that a thorough understanding on flow characteristics of nanofluids is essential for proposing mathematical description nanofluids flow.

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“…Once the size, shape, and volume fraction of the solid particles in the liquid carrier are known, it is easy to characterize the flow behavior in pipes theoretically. 8 Liquid droplet ejections from a fixed orifice have been previously studied in a variety of applications, ranging from the production of spherical nuclear fuel particles 9 to fuel injection into jet engines, 9 as well as inkjet printers. 10 However, there has been a lack of systematic experimental and theoretical studies of droplet injection from vibrating orifices for cryogenic fluids, perhaps due to the extremely complex nature of the problem.…”

Section: Introductionmentioning

confidence: 99%

Numerical study of liquid-hydrogen droplet generation from a vibrating orifice

Celik

Hussaini

et al. 2005

Physics of Fluids

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Atomic hydrogen propellant feed systems for far-future spacecraft may utilize solid-hydrogen particle carriers for atomic species that undergo recombination to create hot rocket exhaust. Such technology will require the development of particle generation techniques. One such technique could involve the production of hydrogen droplets from a vibrating orifice that would then freeze in cryogenic helium vapor. Among other quantities, the shape and size of the droplet are of particular interest. The present paper addresses this problem within the framework of the incompressible Navier-Stokes equations for multiphase flows, in order to unravel the basic mechanisms of droplet formation with a view to control them. Surface tension, one of the most important mechanisms to determine droplet shape, is modeled as the source term in the momentum equation. Droplet shape is tracked using a volume-of-fluid approach. A dynamic meshing technique is employed to accommodate the vibration of the generator orifice. Numerically predicted droplet shapes show satisfactory agreement with photographs of droplets generated in experiments. A parametric study is carried out to understand the influence of injection velocity, nozzle vibrational frequency, and amplitude on the droplet shape and size. The computational model provides a definitive qualitative picture of the evolution of droplet shape as a function of the operating parameters. It is observed that, primarily, the orifice vibrational frequency affects the shape, the vibrational amplitude affects the time until droplet detachment from the orifice, and the injection velocity affects the size. However, it does not mean that, for example, there is no secondary effect of amplitude on shape or size.

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Two-phase flow of solid hydrogen particles and liquid helium

Cited by 30 publications

References 14 publications

CFD simulation of coal-water slurry flowing in horizontal pipelines

CFD simulation of coal-water slurry flowing in horizontal pipelines

Numerical Investigation on the Turbulent Flow Characteristic of Nanofluids in a Horizontal Circular Tube

Numerical study of liquid-hydrogen droplet generation from a vibrating orifice

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