Fluid Science Laboratory Research Articles

DSC (Differential Scanning Calorimetry) used to follow the evolution of W/O emulsions versus time on ground and in space in the ISS

The evolution of W/O emulsion versus time in microgravity conditions has been studied in the framework of the FASES (Fundamental and Applied Studies on Emulsion Stability) project sponsored by the European Space Agency (ESA). The objective of this study was to investigate the evolution of W/O emulsions made of water + paraffin oil + SPAN 80® under purely diffusive conditions (no gravity driven effects) and to compare with evolution of similar emulsions observed on ground. A correlation between the state of dispersion of water and either the freezing temperature during cooling, or the freezing time at a fixed temperature was used to follow the emulsion evolution versus time. For that purpose, two identical calorimeters were built by Airbus (formerly EADS) with the support of the French company SETARAM: The Flight Model (FM) located onboard the International Space Station (ISS) and the Engineering Model (EM) located at the TELESPAZIO Centre in Naples. Dedicated cells were filled on ground with different formulations of W/O emulsions and identical experiments were performed with the FM and the EM models in order to highlight the differences in emulsion evolution. On ground, the experiments were performed by cooling and heating the calorimeter between 40 °C and −60 °C but due to technical constraints in the FM, the experiments performed in the FSL (Fluid Science Laboratory) of the ISS were limited to a lowest temperature of −22 °C. The results obtained with the FM confirmed the formation of emulsions in the dedicated cell with the selected stirring system in space. These results also demonstrated that it is possible to detect the freezing and the melting of the water droplets with the designed calorimeter either during cooling and heating phases or versus time during a temperature holding period at −22 °C. Furthermore, the comparison between both results obtained with the EM on ground and with the FM in space revealed distinct behaviours. This study drove us to focus on other mechanisms than sedimentation and convection to account for the destabilization of these kinds of emulsions.

Recognition and tracking of convective flow patterns using Wollaston shearing interferometry

The GeoFlow experiment on the ISS is designed to study convective flows in a spherical gap under microgravity conditions. The main challenge, however, is the visualization of the fluid flow especially under the safety requirements of the Columbus module. The Wollaston shearing interferometry unit of the Fluid Science Laboratory works by optical means alone and is therefore utilized as measurement device for temperature fluctuations. The resulting interferograms in terms of fringe patterns are the base for the presented advanced post-processing techniques. They are used to identify convective patterns, to track these structures and to reconstruct the inaccessible three-dimensional temperature field. A comparison between experimentally gained results and numerically calculated interferograms is given, too. We show that convective patterns are automatically recognized and tracked accurately in experimental images by means of the generalized structure tensor. Furthermore, generic numerical simulations are used to deduce the internal temperature distribution by comparison with interferograms from the experiment.

Foam generation and sample composition optimization for the FOAM-C experiment of the ISS

End of 2009 and early 2010 a sealed cell, for foam generation and observation, has been designed and manufactured at Astrium Friedrichshafen facilities. With the use of this cell, different sample compositions of "wet foams" have been optimized for mixtures of chemicals such as water, dodecanol, pluronic, aethoxisclerol, glycerol, CTAB, SDS, as well as glass beads. This development is performed in the frame of the breadboarding development activities of the Experiment Container FOAM-C for operation in the ISS Fluid Science Laboratory (ISS). The sample cell supports multiple observation methods such as: Diffusing-Wave and Diffuse Transmission Spectrometry, Time Resolved Correlation Spectroscopy [1] and microscope observation, all of these methods are applied in the cell with a relatively small experiment volume <3cm3. These units, will be on orbit replaceable sets, that will allow multiple sample compositions processing (in the range of >40).

神戸大学大学院 海事科学研究科 エネルギー流体科学研究室

神戸大学大学院 海事科学研究科 エネルギー流体科学研究室

Thermal convection in rotating spherical shells: An experimental and numerical approach within GeoFlow

We present numerical and experimental preliminary studies for a microgravity experiment on thermal convection in rotating spherical shells named GeoFlow, which will be integrated in Fluid Science Laboratory (FSL) at Columbus module of International Space Station (ISS). Numerical studies of this spherical Rayleigh–Bénard problem under a central dielectrophoretic force in microgravity environment are accomplished for a wide range of Rayleigh and Taylor number. For testing GeoFlow framework a laboratory experiment is designed, constructed, and tested including set-up of optical measurement technique (Wollaston shearing interferometry).

The ESA contribution to space research on two-phase systems

This paper gives an overview of the research programme in Heat and Mass Transfer coordinated by the European Space Agency (ESA). This research programme consists of six projects involving more than 30 partners, both academia and industry, spread in 11 countries in Europe, Canada and Israel. The microgravity experiments performed up to now are recalled as well as their main results. Finally, the experiments planned for the coming years, particularly in the Fluid Science Laboratory (FSL) on the International Space Station (ISS), are briefly described.

Project proposal for the investigation of particle-stabilised emulsions and foams by microgravity experiments

The utilisation of particle-surfactants nanostructures as stabilising agents represents today the technologic and scientific frontier in the stabilisation of liquid films in emulsion and foams. This topic will be addressed by the proposal STEFAN (STabilisation of Emulsions and FoAms by Nanoparticles), proposed by European groups in the framework of the ESA AO-2004 for Life and Physical Sciences and Applied Research projects Similarly to what can be observed for surfactant-stabilised emulsions and foams, microgravity provides ideal conditions for the investigation of the hierarchy of involved objects: interfacial layer, liquid film, dispersed systems foam or emulsion. Microgravity experiments are planned by refurbishing the Experimental Container FASES for the ISS Fluid Science Laboratory and the facility FASTER for the European Drawer Rack, already under development in existing research programmes. Here the scientific guidelines of the project are presented together with examples and preliminary results on the effect of nano-particle-surfactant structures adsorbed at liquid interfaces. First experimental results have been achieved for particle monolayers at the water/air interface and a thermodynamic model was derived to describe the obtained surface pressure-area isotherms.

Multimodal astronaut virtual training prototype

A few dedicated training simulator applications exist that mix realistic interaction devices—like real cockpits in flight simulators—with virtual environment (VE) components. Dedicated virtual reality (VR) systems have been utilized also in astronaut training. However there are no detailed descriptions of projection wall VR systems and related interaction techniques for astronaut assembly training in zero gravity conditions. Back projection technology tends to have certain advantages over head mounted displays including less simulation sickness and less restricted user movement. A prototype was built to evaluate the usefulness of projection technology VEs and interaction techniques for astronaut training. This was achieved by first constructing a PC cluster-based general purpose VE software and hardware platform. This platform was used to implement a testing prototype for astronaut assembly sequence training. An interaction tool battery was designed for the purposes of viewpoint control and object handling. A selected training task was implemented as a case study for further analysis based on laptop usage in the Fluid Science Laboratory (FSL) inside the Columbus module in the International Space Station (ISS). User tests were conducted on the usability of the prototype for the intended training purpose. The results seem to indicate that projection technology-based VE systems and suitably selected interaction techniques can be successfully utilized in zero gravity training operations.

Telescience and interferometric metrology on the international space station

Scientific experiments performed in space require real-time control by the scientists on earth, i.e. Telescience/Teleoperation. In fluid science research, non-invasive optical diagnostic tools help to gain a better understanding of phenomena within transparent media. During the last years, electronic cameras started to take over the role of quantitative imaging from photographic imaging. For that purpose cameras must offer at least 1 k × 1 k spatial resolution, 8 bit pixel depth and 33 ms (30 fps) time resolution. This results in data rates (240 Mbps) far beyond the downlink capacities of typical carriers for scientific payloads. A double rack on the International Space Station (ISS), e.g. gets only 2 Mbps continuously. This paper concentrates on the compressibility of interferometric image data for Telescience. In particular, a solution is presented for Electronic Speckle Pattern Interferometry ( ESPI), one of the interferometers, e.g. planned for the Fluid Science Laboratory (FSL) on ISS. Pre-tests had shown that ESPI raw images could hardly be compressed, i.e. by a factor 1–1.5 only. But a factor of 60 is at least required to allow Telescience with an image sequence of 15 fps (120 Mbps), still providing a good qualitative impression about the spatial and temporal behaviour of an experiment. This paper provides answers concerning qualitative imaging with ESPI in addition to Shearing Interferometry and Holographic Interferometry.

The geoflow-experiment on ISS (part I): Experimental preparation and design of laboratory testing hardware

Thermal convection in a spherical shell represents an important model in fluid dynamics and geophysics. Investigations on thermal convective instabilities occuring in the spherical gap flow under terrestrial conditions are of basic importance especially for the understanding of symmetry-breaking bifurcations during the transition to chaos. Microgravity,experiments on thermal convection with a simulated central force field are important for the understanding of large scale geophysical motions as the convective transport phenomena in the Earth's liquid outer core. This report summarizes the concurrent experimental (part I), numerical (part II) and theoretical (part III) studies for the preparation of an International Space Station (ISS) experiment inside the Fluid Science Laboratory (FSL). This special experimental device with respect to geophysical simulations is called GEOFLOW. A central symmetric force field similar to the gravity field acting on planets can be produced using the effect of the dielectrophoretic force field by applying a high voltage potential difference to the inner and outer sphere. Flow visualization, Wollaston Shearing Interferometry and Laser Doppler Velocimetry will be used to determine the expected flow pattern during the space experiments.

Near-critical fluids under microgravity : Highlights and perspectives for Europe

Started more than 15 years ago, the investigation of fluids and liquid mixtures near their gas-liquid or liquid-liquid critical points has led to a number of important findings. We note the determination of critical, universal power law behavior for the specific heat and the adsorption properties near a solid wall. Also came out a unified view of phase separation, which has been later applied to the development of biological patterns. A new, very fast, mechanism of heat transport has been discovered that has been coined piston effect. This effect has been already applied in the space industry. All these findings have been obtained thanks to a good coordination between ESA and CNES (and also with the NASA and USSR - Russian space agencies). The future of the program is linked to the CNES DECLIC facility and the ESA Fluid Science Laboratory (FSL). DECLIC has been designed to extend the interval of temperature regulation beyond the critical temperature of water (550 K) so as to investigate chemical reactions under conditions of supercritical water. Thanks to the construction of a special vibrational Experiment Container for FSL, the thermal and mechanical behavior of fluids under forced vibration can be investigated.

Near-critical fluids under microgravity : status of the eseme program and perspectives for the iss

Started 16 years ago, the ESEME program has led to a number of important findings. We note a simple and unified view of phase transitions, which has been applied to the development of biological patterns, and a very fast thermalization mode that we coined the “piston effect”. This effect has been applied to control the cryogenic reservoirs of the Ariane 5 rocket. All these findings have been obtained thanks to the good coordination of the ESA and CNES space facilities and the construction of high technology experimental modules. The future of the program is linked to the CNES DECLIC facility and the ESA Fluid Science Laboratory (FSL). DECLIC has been designed to increase the temperature regulation above the critical point of water (550 K) so as to investigate chemical reactions under conditions of supercritical water, and in relation to the promising applications of waste treatment by supercritical oxidation. Thanks to the construction of a special vibrational Experiment Container for FSL, the thermal and mechanical behavior of fluids under forced vibration can be investigated. The results of such studies will help to estimate the effect of g-jitter on fluids, and control gases and liquids in space.

Holographic diagnostics of fluid experiments onboard the International Space Station

This paper describes the holographic measurement system planned for accommodation in the ESA Fluid Science Laboratory (FSL), a new facility under development for the Columbus Orbital Facility of the International Space Station. The FSL provides research opportunities for experiments with fluids and transparent media under microgravity conditions. One of the diagnostic tools for experimental analysis is a holographic interferometer. Holography is a method used to record and reconstruct wavefronts. The method has a broad spectrum of applications in the field of fluid physics research on Earth and in a microgravity environment. The size, location and velocity of (tracer) particles inside a fluid volume can be analysed by holography, and refractive index fields and corresponding temperature or concentration profiles can be investigated by holographic interferometry. A number of different techniques/materials are available for hologram recording and reconstruction, e.g. photographic emulsions, thermoplastic films, photorefractive crystals and, recently, direct hologram recording with CCD sensors and numerical reconstruction (digital holography). This paper provides a survey of these methods, defines selection criteria for the FSL and describes the principal geometry of the FSL holographic set-up under development.

Estimates on diagnostic methods for investigations of thermal convection between spherical shells in space

Thermal convection in a spherical shell represents an important model in fluid dynamics and geophysics. Investigations on thermal convective instabilities occurring in the spherical gap flow under terrestrial conditions are of basic importance, especially for the understanding of symmetry-breaking bifurcations during the transition to chaos. Microgravity experiments on thermal convection with a simulated central force field are important for the understanding of large-scale geophysical motions such as the convective transport phenomena in the Earth's liquid outer core. More than one diagnostic tool is needed to examine and characterize the different flow types. Flow visualization, Wollaston shearing interferometry and laser Doppler velocimetry should be available for space experiments. This report summarizes concurrent theoretical, numerical and experimental studies for the preparation of a Get Away Special (Shuttle) experiment as well as a Space Station experiment inside the Fluid Science Laboratory. The special experimental device for investigations of supercritical and turbulent thermal convection in spherical shells under a central force field with respect to geophysical simulations is called an electrohydrodynamic container. A central symmetric force field similar to the gravity field acting on planets can be produced using the effect of the dielectrophoretic force field by applying a high-voltage potential difference to the inner and outer sphere.

An integrated optical set-up for fluid-physics experiments under microgravity conditions

An integrated optical set-up for fluid-physics diagnostics is proposed. The combined diagnostic tools are direct visualization, the schlieren technique, electronic speckle-pattern interferometry, differential interferometry, digital holography and holographic interferometry with a photorefractive crystal. The sharing of most of the optical lenses allows a compactness of hardware compatible with space-application requirements (the Fluid Science Laboratory for the International Space Station). Performances and complementarity of techniques are discussed. Interferometric methods for refractive-index measurement are compared and preliminary experimental results are given.