Thermal cycle around the critical point of carbon dioxide under reduced gravity

Guénoun, P.; Khalil, B.; Beysens, Daniel; Garrabos, Yves; Kammoun, Fahmi; B, Le Neindre; Zappoli, Bernard

doi:10.1103/physreve.47.1531

Cited by 85 publications

(31 citation statements)

References 20 publications

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“…and [14][15][16] is the characteristic length of an "ideal" experimental cell made of materials of infinite conductivity [V fluid is the cell volume, A CBL is the external cell area where the cold boundary layer (CBL) develops during the quench]. The actual sample geometry leads to l ≈ 1 mm.…”

Section: Experimental Control Of the Sample Equilibration Related To mentioning

confidence: 99%

Turbidity Data of Weightless SF6 Near its Liquid–Gas Critical Point

Lecoutre¹,

Garrabos²,

Georgin³

et al. 2009

Int J Thermophys

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Light transmission measurements performed in SF 6 close to its liquidgas critical point are used to obtain turbidity data in the reduced temperature rangeAutomatic experiments (ALICE 2 facility) were made at a near critical density, i.e., ρ −ρ c ρ c = 0.8 %, in the one-phase homogeneous region, under the microgravity environment of the Mir Space Station ( ρ is the average density, ρ c is the critical density). The turbidity data analysis verifies the theoretical crossover formulations for the isothermal compressibility κ T and the correlation length ξ . These latter formulations are also used to analyze very near T c thermal diffusivity data obtained under microgravity conditions by Wilkinson et al. (Phys. Rev. E 57, 436, 1998).

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Section: Experimental Control Of the Sample Equilibration Related To mentioning

confidence: 99%

Turbidity Data of Weightless SF6 Near its Liquid–Gas Critical Point

Lecoutre¹,

Garrabos²,

Georgin³

et al. 2009

Int J Thermophys

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“…It has been shown that the strong thermal expansion (or contraction) of the fluid occurring in the vicinity of the heated (or cooled) boundary of the cell caused, by adiabatic compression (or expansion) of the bulk, uniform heating (or cooling) on a very short time scale compared to that of thermal diffusion, the time scale for the latter diverging as the critical point is approached. Different experimental studies [6][7][8][9][10][11][12][13] have evidenced this mechanism, the so-called piston effect, and have confirmed theoretical predictions, at least to a certain extent. Indeed, several factors can strongly complicate a comparison with this theory.…”

Section: (Received 21 October 1999)mentioning

confidence: 60%

Rapid Thermal Relaxation in Near-Critical Fluids and Critical Speeding Up: Discrepancies Caused by Boundary Effects

2000

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We present one-dimensional numerical simulations reporting the temperature evolution of a pure fluid subjected to heating near its liquid-vapor critical point under weightlessness. In this model, thermal boundary conditions are imposed at the outer edges of the solids in contact with the fluid. Our investigations concern the thermal conditions at the edges of the fluid and their consequences on the fluid's global response. The results for piston effect heating are shown to be significantly affected by the simulation of the solid boundaries. Concerning critical speeding up, it is even found that taking conductive solids into account can make the bulk fluid temperature change in a way opposed to that predicted in their absence.

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“…Recall the two periods of the density relaxation: firstly, a short piston-effect time period during which the temperature relaxes to equilibrium (to first order) while the density relaxes to the order of magnitude it would have had if the fluid was an ideal gas; secondly, a divergent long heat-diffusion time period where density follows the relaxation of the second-order temperature inhomogeneities. Zero gravity experimental studies also report a very long density relaxation time [4]. In the 1g case, Boukari et al [2] numerical solution for 1-D convectively stable flow equations has shown that the density profile can take hours to form, whereas temperature equilibrates very quickly through the piston effect.…”

Section: Density Relaxationmentioning

confidence: 99%

Interaction Between the Piston Effect and Gravitational Convection

Zappoli

Beysens

Garrabos

2014

Heat Transfers and Related Effects in Supercritical Fluids

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Strong gravitational instabilities are observed on the ground in heated near-critical fluids. However, the piston effect homogenizes temperature. The origin of strong convective instabilities in a near homogeneous pure fluid addresses the question posed by the evaluation of the interaction between the gravitational convection and the piston effect. After a brief one-dimensional model generalization to the two-or three-dimensional models subjected to a vertical steady state acceleration, the two-dimensional studies of the experimental heating are detailed for two configurations: a side-heated cavity and an immersed point heat source.

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Thermal cycle around the critical point of carbon dioxide under reduced gravity

Cited by 85 publications

References 20 publications

Turbidity Data of Weightless SF6 Near its Liquid–Gas Critical Point

Turbidity Data of Weightless SF6 Near its Liquid–Gas Critical Point

Rapid Thermal Relaxation in Near-Critical Fluids and Critical Speeding Up: Discrepancies Caused by Boundary Effects

Interaction Between the Piston Effect and Gravitational Convection

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