Marangoni convection is induced by the variation of surface tension along a free surface, which depends not only on temperature but also concentration. However, the onset of thermo-solutal Marangoni convection in a liquid bridge system is still unknown. Here, we perform a global linear stability analysis to determine the theoretical onset of the Marangoni convection occurring in the half-zone liquid

Trajectories of free-floating droplets burned in experiments on the International Space Station (ISS) are evaluated from digital images. n-Heptane droplets are observed to move in irregular paths after cool flame extinction with acceleration levels of tens or hundreds of μg and frequencies of 0.2 - 0.3 Hz. Flame oscillations for burning methanol and n-heptane droplets can affect droplet acceleration

The high precision multi-target acquisition, pointing and tracking (APT) technology under satellite micro-vibrations is urgently required with the increasing demand on space science missions. This paper thus presents one APT system simultaneously exhibiting the high accuracy and multi-target laser link functions. The performance of the APT system is investigated through verification simulation considering

An experiment is conducted to test the transient characteristics of a re-entrant grooved wick heat pipe, and the transient thermal response characteristics of the ammonia-aluminum heat pipe in the horizontal status during startup and shutdown stage is analyzed. The transient axial distributions of the wall temperature of the heat pipe have been obtained. Moreover, the influence of heat load and operating

In this work, we compare the performance of two different methods for generating bubbles in conditions relevant to microgravity. A T-junction formed by two cylindrical (1 mm of internal diameter) and perpendicular channels is used to generate trains of non-wetting bubbles. Air and distilled water are used as dispersed and continuous phases, respectively. The difference between both methods lies in

An efficient long-term storage of cryogenic propellants is a challenge for future space exploration missions. The vapour bubbles formed as a result of boil-off in the tank walls can generate foam structures, which could be hazardous in different operations in orbit. A recently proposed approach to control the dynamics of bubbles is based on the generation of an acoustic field by means of a piezoelectric

Analysis has been made on a possibility of phase separation and critical point as a solution of fine particles in plasmas, extending the previous work which pointed out this as one of two such possibilities. Fine particles are treated as a solute in the solvent of weakly coupled plasmas of electrons and ions. Examples of phase diagram have been obtained and coexisting phases are shown to have fine

In this work, we study the transition from squeezing to dripping during the formation of bubbles in a capillary T-junction in conditions relevant to microgravity. The junction is formed by two perpendicular cylinders of equal section (1mm of internal diameter). The capillary number Ca (based on the continuous phase) is used as the key parameter of the study. For the range of Ca covered in this paper

High G forces affect cognitive functions. Withstanding to the negative effects of G forces is positively correlated with pilots’ readiness and countermeasures that were taken against. Therefore, factors that decrease resistance to G-forces will increase G induced cognitive impairment. Changes in blood pressure affect the cerebral perfusion and disrupt high cortical functions. We investigated the negative

Based on the Couette parallel plate shear flow model, it was investigated on the effects of the gravity level and the liquid-gas viscosity ratio (λ) on the bubble deformation and the apparent viscosity of the bubbly suspension with the volume of fluid method. The results show that, for a given bubbly suspension, the effect of gravity on the bubble deformation and the relative viscosity is great when

This paper presents a series of numerical simulations on the effect of heat dissipation on the thermocapillary convection of a low Prandtl number (Pr = 0.011) fluid in an annular pool heated from its inner cylinder. The radius ratio and the aspect ratio of the annular pool set as η = 0.5 and ε = 0.1, respectively. The results show that with the increase of Biot number, the isotherms of the two-dimensional

The paper analyzes the situation on a prototype small spacecraft “Aist” after the degradation of the battery. The main problems of evaluating microaccelerations in the internal environment of the prototype small spacecraft “Aist” are noted. The ways of solving the problems are shown. An assessment of microaccelerations based on current from solar panels is presented. The results of the work can be

We consider forced oscillations of a oblate fluid drop, which is surrounded by another liquid and confined between two parallel rigid plates subject to vibrations. The axisymmetrical vibration force is parallel to the symmetry axis of the drop. The velocity of the contact line motion is proportional to the deviation of the contact angle from its equilibrium value. The proportionality factors are different

For keeping microgravity level of microgravity and space science satellites, a kind of electric thruster, the radio-frequency ion thruster (RIT) has been designed and applied. The RIT produces thrust through ionizing neutral particles in the discharge chamber and extracting ions by the ion optics system. The length of discharge chamber affects the ionization of neutral particles as well as the performance

The theoretical approaches for mathematical modelling of the convective flows with mass transfer through the liquid–gas interface are discussed. The special attention is payed to modelling with use of the classical Boussinesq approximation of the Navier–Stokes equations. The diffusion equation and the effects of thermodiffusion and thermal diffusivity (the Soret and Dufour effects) are taken into account

In order to reveal the influence of nanoparticle shape on heat transfer in nanofluid nucleate boiling process, a three-dimensional numerical investigation of nanofluid thermocapillary convection around a gas bubble is conducted. Five different shaped nanoparticles are used in this study and the nanofluid flow is simulated by two-phase mixture model. The thermocapillary convection intensity of nanofluid

Fuel tanks are a core component in satellites that manage the propellant. This study numerically analyzed the fluid transport with parallel guide vanes in a vane type surface tension tank. Flow3D was used to simulate fluid transport in microgravity in a scale model with 15% liquid filling rate with comparisons to experimental data. Then, the simulations were used to compare the leading edge climbing

In space environment, the adhesion effects can cause a high adhesion component of a friction force, and the impact effects caused by the microgravity can induce a high ploughing component, so the friction force is higher than the ground environment. Nanoscale textures affect the adhesion behaviors by reducing contact areas, and they also vary the shear strength of the interface, which are beneficial

In order to reduce the interference of space environment in space microgravity experiments, one drag-free and attitude control system could be used in space science experiments to compensate non-conservative forces and to minimize residual disturbances of the satellite. As the main parts of the drag-free control system, noises of thrusters and GPS receivers have significant impacts on the performance

A joint motion of thin liquid film and dry gas in a microchannel is investigated numerically at different values of initial concentration of the liquid vapor in the gas phase, taking into account the evaporation process. Major factors affecting the temperature distribution in the liquid and gas phases are as follows: transfer of heat by liquid and gas flows, heat loses due to evaporation, diffusion

Problem of thermocapillary convection is studied to analyze peculiarities of the flows arising in a gas–liquid system under action of an intense local thermal exposure. The “stream function–vorticity” formulation of the Navier–Stokes equations in the Boussinesq approximation is used to describe the fluid flows. The kinematic and dynamic conditions on the free boundary are stated in terms of tangential

The nonlinear sideband thermocapillary instability of a thin liquid film coating the inside of a heated cylinder in the absence of gravity is investigated. It is shown that for a newtonian fluid and under the approximation of small wavenumber and large radius of the cylinder, the axial and all azimuthal modes with wavenumber kmax > 0 have the same linear maximum growth rate, in the same way as in a

To cooperate with the Chinese TG-2 space experiment project, the transition routes to chaos of buoyant-thermocapillary convection were experimentally researched in large-scale liquid bridge of 2cSt silicone oil with 20 mm in diameter. A Nanovoltmeter with high resolution was adopted to measure the dynamical temperature oscillations, as well as to detect the convective transitional behaviors which were

Joule heating near ion-selective cation-exchange membranes in an external electric field can cause two modes of instability, namely, the thermogravitational convection, which reminds a well-known Rayleigh–Benárd convection, and a novel type of instability, the thermoelectrokinetic instability. Stability of a quiescent one-dimensional steady-state solution to infinite small sinusoidal perturbations

We present the experimental study of convection in a horizontal liquid layer (ethanol, 3-mm deep), evaporating from a localized surface (10 × 10 mm2) into the gas flow (air). Visualization and measurements of the two-component velocity field in the liquid layer has been carried out with the Particle Image Velocimetry (PIV) technique. In our experiments we consider a novel configuration in which the

As a typically highly efficient two-phase heat transfer under cryogenic temperature range, the operation performances of cryogenic loop heat pipes (CLHPs) might be affected by the relative location of different components. A transient mathematical model is established in present work. The model validation is demonstrated by comparing the simulation results with an auxiliary loop type neon-charged CLHP

The loss of stability of the horizontal interface in a two-layer system of immiscible liquids with a diffusing component was investigated experimentally. To this end, the evolution of the system, which was based on a mixture of chlorobenzene and benzene (lower layer) and water or an aqueous solution of sodium chloride (upper layer) was examined. At the beginning of the experiment, the diffusing component

In this study, the freezing of water inside the channel with constant wall temperature was studied numerically. At the entrance of the channel, the velocity profile is assumed. The thermophysical properties of the fluid, including density, thermal capacity, thermal expansion coefficient and viscosity, are function of the temperature and the volume fraction of ice. Nonlinear equations of continuity

To solve the heat dissipation problem of high heat flux components on spacecraft, experiments were carried out to investigate the flow boiling heat transfer characteristics of ammonia in a microchannel heat sink. Verified by gravity-independent criteria, the experimental results can be used to predict the performance of flow boiling heat transfer in microgravity environment. The heat sink consisted

We studied fuel atomization in an air-assisted atomizer of aircraft engine with volume-of-fluid method in microgravitation approximation under the conditions closer to the ones of the operating cruise mode. The problem was looked upon in a two-dimensional axisymmetric configuration, including the simulation of the swirl velocity and in a three-dimensional configuration. We found a drop-size distribution

This study aims to express an optimize temperature profile with the most heat transfer and least work loss by minimizing the total entropy generation of a pipeline under external magnetic field. This study has investigated in low Stokes number and low Reynolds number conditions. It shows that, the fluid’s shear stress increases around the wall (r* > 0.8), due to presence of magnetic field. As a consequence

For future space transportation and planetary exploration mission power applications, NASA Glenn Research Center (GRC) is currently developing a small-scale nuclear fission system (i.e. Kilopower system), which has an operable range of 1 to 10 kWe and a design life of 8 to 15 years. The thermal management system of Kilopower system involves two types of heat pipes: high temperature alkali metal heat

Abstract Micro-scale systems have gained considerable attention in recent years and a large amount of researches have been done in this field. In this study, the hydrodynamic interference of a droplet is comprehensively investigated under surface acoustic waves. This paper reveals the effects of some control parameters such as wave amplitude and wave frequency on the dynamical behavior of droplet.

Abstract The linear and weakly nonlinear stability of a doubly diffusive electrically conducting non-Newtonian couple stress fluid layer in the presence of a uniform vertical magnetic field is investigated. The system behaves like a triply diffusive one with the magnetic field as a third diffusing component. Several remarkable departures from those of doubly diffusive couple stress fluid systems are

Abstract Microgravity and vacuum are two main environments in outer space. In the microgravity environment, vibration is a typical phenomenon, and it will induce a reciprocating sliding contact between a journal and a bearing in a clearance joint. In vacuum environment, the adhesion effects are severe, and the friction forces are much higher than the ground environment. Nanoscale textures can reduce

Abstract Numerical simulations of microbubble formation in a co-flowing liquid in Polydimethylsiloxane (PDMS) microfluidic chip by COMSOL Multiphysics are carried out based on the Level-Set Method. The growth process of bubbles in a co-flowing focusing environment with different liquid flow rates and gas pressures is successfully described by numerical simulation, and the simulation predictions are

Abstract In this paper, an experimental study of boiling-up of a superheated water jet at an outflow through a short slit nozzle into the atmosphere in the presence of a passive swirler (twisted tape, wire winding) has been carried out in order to affect and control the jet behavior. The evolution of jet disintegration with increasing liquid superheat during the outflow both from the saturation line

Abstract The interface distribution and self-pressurization phenomenon are the most important problems in the storage of cryogenic liquid on orbit, which are difficult to be predicted and assessed exactly due to the complex non-equilibrium thermal behavior. In this paper, one 3-D CFD model based on volume of fluid (VOF) method is established to investigate the interface evolution and self-pressurization

Abstract One cause of thrombocytopenia in astronauts after spaceflight is decreased platelet production. To increase our understanding of thrombopoiesis in humans while in space, we investigated the effects of simulated microgravity, achieved using a random positioning machine (RPM), on megakaryoblastic cells (MEG-01 cell line). Exposure of MEG-01 cells to simulated microgravity for up to one week

Abstract Concentration-induced convection of a binary metal melt in a rectangular crucible has been studied numerically in the case of a mixture with a eutectic phase diagram. The calculations are performed for realistic parameters which correspond to the pair of metals Sn-Pb. A solid rod with non-wettable boundaries and a non-uniform longitudinal temperature distribution on the surface is immersed

Abstract The influence of gravity (including 0 G, 0.16 G, 0.38 G, 1 G and 1.8 G) on the antisolvent crystallization of L-histidine was investigated in a self-designed micro-channel crystallizer on a zero-G flight, which was successfully launched on June 13th, 2018. The stable form of L-histidine was obtained under microgravity, while only the metastable form can be observed in the ground experiments

Abstract An influence of a spatial temperature modulation of the heat release/consumption at the interface on nonlinear convective flows in the 47v2 silicone oil - water system, has been investigated. Two types of boundary conditions on lateral walls: periodic boundary conditions corresponding to laterally infinite two-layer system and rigid heat-insulated lateral walls corresponding to the closed

Abstract Analysis of three different equations of state suitable for describing fluids near the thermodynamic critical point is performed. Numerical simulation of the piston effect (adiabatic heating) with the use of the equations of state is carried out. The range of temperature distances to the critical point in which the calculated time of the piston effect is equal to the analytical time is defined

Abstract The theory of long nonlinear oscillating wave packets (breathers) in a stratified fluid with a small density difference in a gravitational field is developed. The theory is based on the Gardner equation and its modifications, which are fully integrable with modern methods of the nonlinear wave theory. Examples of the breather generation are given and the conditions for their stability are

Baker's yeast (Saccharomyces cerevisiae) has broad genetic homology to human cells. Although typically grown as 1-2mm diameter colonies under certain conditions yeast can form very large (10 + mm in diameter) or 'giant' colonies on agar. Giant yeast colonies have been used to study diverse biomedical processes such as cell survival, aging, and the response to cancer pharmacogenomics. Such colonies

Diamagnetic samples placed in a strong magnetic field and a magnetic field gradient experience a magnetic force. Stable magnetic levitation occurs when the magnetic force exactly counter balances the gravitational force. Under this condition, a diamagnetic sample is in a simulated microgravity environment. The purpose of this study is to explore if MC3T3-E1 osteoblastic cells can be grown in magnetically

The first International Caenorhabditis elegans Experiment (ICE-First) was carried out using a Russian Soyuz spacecraft from April 19-30, 2004. This experiment was a part of the program of the DELTA (Dutch Expedition for Life science Technology and Atmospheric research) mission, and the space agencies that participate in the International Space Station (ISS) program formed international research teams

The effects of simulated microgravity on two bacterial isolates, Sphingobacterium thalpophilium and Ralstonia pickettii (formerly Burkholderia pickettii), originally recovered from water systems aboard the Mir space station were examined. These bacteria were inoculated into water, high and low concentrations of nutrient broth and subjected to simulated microgravity conditions. S. thalpophilium (which

Experiments that are done under microgravity, e.g. during space or parabola flights, are invariably accompanied and affected by ubiquitous vibrations of the surroundings. Vibrations induce Quickly Changing Acceleration Forces (QCAFs) that interfere with the perception of the earth gravitational field. To investigate their impact on experiments under microgravity we monitored the vibrations of the airplane

To understand further the role of gravity in osteoblast attachment, osteoblasts were subjected to hypergravity conditions in vitro. Scanning electron microscopy of all confluent coverslips from FPA units show that the number of attached osteoblasts was similar among gravitational levels and growth durations (~90 cells/microscopic field). Specifically, confluent 1.0 G control cultures contained an average

It has been repeatedly shown earlier that some fish of a given batch reveal motion sickness (a kinetosis) at the transition from 1 g to microgravity. In the course of parabolic aircraft flight experiments, it has been demonstrated that kinetosis susceptibility is correlated with asymmetric inner ear otoliths (i.e., differently weighed statoliths on the right and the left side of the head) or with genetically

The number one priority for any manned space mission is the health and safety of its crew. The study of the short and long term physiological effects on humans is paramount to ensuring crew health and mission success. One of the challenges associated in studying the physiological effects of space flight on humans, such as loss of bone and muscle mass, has been that of readily attaining the data needed

Bacteria exhibit varying responses to modeled reduced gravity that can be simulated by clino-rotation. When Escherichia coli was subjected to different rotation speeds during clino-rotation, significant differences between modeled reduced gravity and normal gravity controls were observed only at higher speeds (30-50 rpm). There was no apparent affect of removing samples on the results obtained. When

Euglena gracilis and its close relative Astasia longa show a pronounced negative gravitactic behavior. Many experiments revealed that gravitaxis is most likely mediated by an active physiological mechanism. The goal of the present study was to examine elements in the sensory transduction by means of inhibitors of gravitaxis and the intracellular calcium concentration during short microgravity periods

Using new flight hardware, a Chinese mission of space protein crystallization has been performed aboard the Chinese spacecraft SZ-3. Preliminary analyses of the experimental results have shown that a few proteins produced better crystals in space. At least, the crystals of cytochrome b5 mutant could diffract X-ray beyond the highest resolution reported so far for the same kind of crystals. In addition

Numerical simulations are carried out to investigate the crystallization process of a protein macromolecular substance under two different conditions: pure diffusive regime and microgravity conditions present on space laboratories. The configuration under investigation consists of a protein reactor and a salt chamber separated by an "interface". The interface is strictly related to the presence of

The space experiment TRAMP (Thermal Radiation Aspects of Migrating Particles) flown in 1999 onboard the mission Foton 12 sponsored by the European Space Agency (ESA), was conceived to reveal and measure a new kind of forces, named Thermal Radiation Forces (TRF). The experiment was dramatically disturbed by the occurrence of undesired convective motions due to the rotation of the spacecraft. Apart from

Cultures of Escherichia coli grown in space reached a 25% higher average final cell population than those in comparably matched ground controls (p<0.05). However, both groups consumed the same quantity of glucose, which suggests that space flight not only stimulated bacterial growth as has been previously reported, but also resulted in a 25% more efficient utilization of the available nutrients. Supporting

We describe a centrifuge designed and constructed according to current demands for a versatile instrument in cellular gravitational research, in particular protists (ciliates, flagellates). The instrument (called CECILIA, centrifuge for ciliates) is suited for videomonitoring, videorecording, and quantitative evaluation of data from large numbers of swimming cells in a ground-based laboratory or in

For the purpose of bio-electronics, bacteriorhodopsin was crystallized into two habits through liquid-liquid-diffusion, namely individual needles of up to 1.9 mm in length and needle bunch-like clusters of up 4.9 mm in total length. In both the reduced gravity experiments performed, the morphology of the individual needles (crystal form A) had improved in terms of sharp needle edges and compact needle