Solutal-thermo-diffusion convection in a vibrating rectangular cavity

Chacha, M.; Saghir, M.Z.

doi:10.1016/j.ijthermalsci.2004.04.013

Cited by 19 publications

(7 citation statements)

References 19 publications

(26 reference statements)

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“…Chacha and Saghir [20] continued their research on solutal thermo diffusion convection in a vibrating rectangular cavity. As well as their last research on this area, they simulated methane (20%) and normal butane (80%) mixture subject to a temperature difference on its lateral walls and radiation heat transfer on the horizontal walls.…”

Section: Literature Reviewmentioning

confidence: 99%

“…Many reasons such as experiment operation, life-support systems, equipment operation, aerodynamic drag, gravity gradient, crew activities, and rotational effects as well as the vehicle structural resonance frequencies18 Weightlessness is an ideal condition which cannot be assessed in practice as a result of the various sources of acceleration present in an orbiting spacecraft.Because the environment in which experiments are performed is not zero gravity; consequently, experiments can be affected by the residual acceleration due to their relation with acceleration magnitude, orientation and duration, frequency. Hence, experimenters must know what the environment was when their experiments were executed in order to analyze and correctly interpret the consequence of their experimental data.The NASA GRC Principal Investigator Microgravity Services project has the responsibility for practicing and archiving acceleration measurements, analyzing these measurements, characterizing the reduced gravity environment in which the measurements were taken, and providing expertise in reduced gravity environment assessment for a range of carriers platforms and facilities such as the Space Shuttle, parabolic aircraft, sounding rockets, drop towers and the ISS19 in support of the NASA's PSD PIs20 . The PIMS21 project supports PIs from various science disciplines for example biotechnology, fluid physics, combustion science, material science and fundamental physics.…”

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confidence: 99%

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Effect of micro vibration from two space platform on liquid mixture during thermodiffusion experiment

Ahadi¹

2021

Preprint

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In the present study, a two-dimensional numerical simulation was carried out for binary mixture. The influence of micro gravity vibration or acceleration on board Iinternational Space Station and FOTON-M3, influence of different cavities size as well as the effect of the sign of the Soret coefficient (fluid flow, heat and mass transfer and concentration) in the solvent were investigated in detail. It must be noted that based on previous experiences with this investigation using the same mixture and cavity by Saghir and Parsa [

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Section: Literature Reviewmentioning

confidence: 99%

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confidence: 99%

Effect of micro vibration from two space platform on liquid mixture during thermodiffusion experiment

Ahadi¹

2021

Preprint

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“…The flow showed synchronous response to the oscillatory accelerations. Later, Chacha and Saghir [37] studied the effect of the time-dependent vertical gravity vector in a rectangular cell on the mass diffusion in a binary fluid mixture subject to a lateral temperature gradient. The effect of varying diffusion coefficients with the temperature and the fluid composition were analysed and compared to the average constant values.…”

Section: Vibration Effects On Diffusion In a Reduced Gravity Environmentmentioning

confidence: 99%

Influence of Vibration on Diffusion in Liquid Mixtures On-Board the International Space Station

Parsa¹

2021

Preprint

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Experiments on-board the International Space Station experience a convective flow due to the oscillatory g-jitters induced by several sources such as crew activities, mechanical systems, thrusters firing, spacecraft docking, etc. Although g-jitter seems to have a major impact on diffusion-related experiments in Space, very few experimental studies have addressed this topic. This study examined the effect of oscillatory g-jitters on transport processes (fluid flow, heat transfer and mass transfer). Cubic rigid cells filled with water and isopropanol at different concentrations were subjected to thermal gradients and forced vibrations. The cells were exposed to different levels of vibration in terms of frequency and amplitude, which were applied perpendicular to the temperature gradient. The full transient Navier Stokes equations coupled with the mass and heat transfer formulas were solved numerically using the control volume technique. The physical properties of the fluid mixture such as the density were determined using two different models. The effect of different levels of vibration on the flow was analysed and the results were compared in a benchmark study with other scientific groups. The effect of the diffusion coefficients variation and other physical properties on the temperature and concentration distribution was compared to those results obtained with constant diffusion coefficients. Results show that use of variable physical properties in the modelling produces different flow patterns and component concentration. By examining different flow patterns, it was found that the effect of using variable coefficients is much more significant in the cases with high Rayleigh vibration that result in strong flow when compared with numerical analysis using constant variables. The numerical analysis was also performed for the actual experiment on board the International Space Station. The same trend was seen for both the numerical and experimental results. However, the separation of components was higher in the experiment in comparison with the numerical analysis. This was discussed in detail for various scenarios in terms of the applied frequency and amplitude. Recommendations are made according to the findings from this study for the improvement of accuracy in the numerical and experimental analyses of future diffusion experiments in Space.

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“…Another type of non-gravitational thermal convection is the thermophoresis (also thermomigration, thermodiffusion, the Soret effect, or the Ludwig-Soret effect) in which mixtures of mobile particles display different responses to the force of a temperature gradient, nevertheless the phenomenon is observed at the scale of one millimeter or less. In regard to the use of solutions, there are not any work exploring the potential use of them for driven a convective mechanism per se, and so far only solutal thermodiffusion aspects have been addressed, as far as the author knows, see for example, [45]- [47].Most recently, the possibility to run a solar thermosyphon by working with a solution was investigated, [42], [43]. In those works, convection was induced either by buoyancy-induced force owing to dependence of density with salt concentration or by evaporation at collectors.…”

Section: Introductionmentioning

confidence: 99%

On osmotic heat engines driven by thermal precipitation-dissolution of saturated aqueous solutions

Arias

2018

International Journal of Thermal Sciences

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Cyclic thermal precipitation and dissolution of saturated aqueous solutions and its significance with regard to osmotic heat engines (OHEs) is discussed. Here, the thermal dependence of the solubility of aqueous solutions is harnessed by alternating thermal solute precipitation and dissolution when heat is either applied (by heating the solution) or extracted (by cooling the solution) depending of the given solution. Utilizing a simplified physical model, it is shown that by the proper choice of the concentration of the given aqueous solution it is possible a closed cycle. Because in contrast with traditional OHEs working with dilute solutions, here the proposed engine operates at saturation concentrations and therefore the approximation of dilute solution might not be valid, an osmotic coefficient was included in the calculations to take account the deviation from the ideal case of a dilute solution. The expression for the extractable energy per unit of volume of solution as well as the thermal efficiency of the heat engine were derived considering the spontaneous change in the Gibbs free energy and enthalpy of precipitation for the thermal efficiency of the engine. The specific case for for Na2SO4 was analyzed and it was found a percentage of Carnot efficiency as high as 23 % which is a little larger than the efficiencies reported by traditional OHEs. Even if its is considered several irreversibilities and uncertainties an assumed an efficiency equal than traditional OHEs, the proposed heat engine eliminates the need of evaporation to re-concentrate the draw solution and then the constraint of working with solutions with high vapor pressures where here a solution can be placed as close as the saturation point by controlling its initial concentration.

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Solutal-thermo-diffusion convection in a vibrating rectangular cavity

Cited by 19 publications

References 19 publications

Effect of micro vibration from two space platform on liquid mixture during thermodiffusion experiment

Effect of micro vibration from two space platform on liquid mixture during thermodiffusion experiment

Influence of Vibration on Diffusion in Liquid Mixtures On-Board the International Space Station

On osmotic heat engines driven by thermal precipitation-dissolution of saturated aqueous solutions

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