As a simple, fast and effective 3D printing method, direct-ink-writing (DIW) has potential applications in repairing the circuit board in orbit, printing the wearable devices for the astronaut, and producing the solar cells for the energy supply in space. To expand the DIW technology to space, we designed the colloidal material box (CMB) as the prototype printer of DIW and verified its applicability

Adequate mechanical stimulation is essential for cellular health and tissue maintenance, including articular cartilage, which lines the articulating bones in joints. Chondrocytes, which are the sole cells found in articular cartilage, are responsible for matrix synthesis, maintenance and degradation. It is generally believed that chondrocytes require mechanical stimuli through daily physical activity

The large columnar patterns resulting from the frozen wave instability in zero gravity conditions are investigated numerically for finite containers of immiscible liquids. The mode selection process is affected by forcing amplitude, frequency, container size and the vibroequilibria effect. The final columnar states are often approximately left-right symmetric and a quantitative measure of their asymmetry

Dilute ensembles of granular matter (so-called granular gases) are nonlinear systems which exhibit fascinating dynamical behavior far from equilibrium, including non-Gaussian distributions of velocities and rotational velocities, clustering, and violation of energy equipartition. In order to understand their dynamic properties, microgravity experiments were performed in suborbital flights and drop

The dynamics of a heavy cylindrical body in a horizontal cylindrical cavity filled with a viscous liquid and subjected to modulated rotation is experimentally investigated. In experiment the cylinders with different moment of inertia are used. Periodic variation (modulation) of cavity rotation rate leads to the azimuthal oscillations of the body in a uniformly rotating reference frame due to viscous

Taking centrifuge system for space utilization as the research object, an active air-cooling thermal control system is put forward. Physical models of the centrifuge thermal control system are built on the basis of simplifying assumptions under actual conditions. A numerical calculation model of centrifuge system is established by using the sliding mesh technique and flow resistance model of heat exchanger

The GRADFLEX experiment of ESA has shown that under microgravity conditions a stationary thermodiffusion process is accompanied by giant non-equilibrium fluctuations with size as large as the size of the sample. In the presence of small concentration gradients, the features of the non-equilibrium fluctuations can be described by means of linearized hydrodynamics. However, the linear models are not

The Marangoni convection during isopropanol volatilization to a single nitrogen bubble with the deformable interface is investigated by combining the Volume of Fluid model and the Level Set method. Both the deformation of the bubble and the thermal effect accompanying with the mass transfer are taken into account. The Marangoni convection is investigated under non-gravity and gravity conditions respectively

The original version of this article unfortunately contained mistakes introduced during the production process. In the caption of Fig. 9, “|phic” should be read as “ϕc”.

The multiscale boiling project, also known as RUBI, is an experimental project supported by the European Space Agency (ESA) focusing on the nucleate boiling within the framework of the utilization of the International Space Station (ISS). In order to investigate the operational behavior of the experimental components and determine a promising parameter range, an experimental setup with the same heater

In this study, effect of lateral vibrations on the thermo-solutocapillary convection and surface behavior in a liquid bridge of toluene/n-hexane solution has been studied numerically under microgravity. The Navier-Stokes equations coupled with the concentration diffusion equation are solved on a staggered grid, and the level set approach is used to capture the deformation of free surface. Present results

In order to understand the dynamic behaviors of the charged water droplet in the presence of electric field, the experimental investigation is conducted in this paper. A uniform DC electric field is produced by applying high voltage between two parallel copper plates which are placed horizontally in a silicon oil tank. The variation range of the electric field intensity is 0–6.67 kV/cm. Under the influence

A comparative analysis of steady flow excited by an oscillating core in a rotating spherical cavity with a liquid is carried out in different cases: when the core is free and performs differential rotation, and when the core differential rotation is absent. In the cavity reference frame the core, whose density is less than the density of the liquid, oscillates near the cavity center under the action

In order to research the influence of the guide vane on liquid transmission performance in a tank under microgravity, simulation analysis was carried out with FLOW-3D software. Firstly, it compared the working condition under the charging rate of 10% with the corresponding experiment results of the drop tower and validated the correctness of the simulation process. And then it changed the structure

Regular ripples at the interface between the granular medium and the fluid in a rapidly rotating cylinder are experimentally studied. We consider two types of ripple formation. First, the ripple formation in a uniformly rotating horizontal cylinder filled with granular medium, fluid and air. In this case, oscillations of the multiphase system in the rotating reference frame are excited by gravity.

A vertical falling Newtonian liquid film flow is inherently unstable to surficial long-wave disturbances. Imposing external oscillation can stabilize the long-wave instability, but also triggers additional parametric instabilities. The effect of oscillation frequency on the stability is subtle. By using the “viscosity-gravity” scaling, the effect of oscillation frequency on the stability can be investigated

Ground-based microgravity experiment facility for large deployable structures based on the force balance was used in deployment function experiments and profile precision estimations. Considering how to exert the balance force in an accurate and efficient way to reduce its adverse effects and improve the realism of the simulated space environment. In this paper, a deformation displacement model of

This work presents the preliminary characterization of the vibrational environment of the DCMIX4 thermodiffusion experiment conducted onboard the ISS from December 2018 to March 2019. Given the long duration of each one of the 58 runs of the campaign and to ensure a correct interpretation of the results, an accurate analysis of acceleration levels all along the experiment is advisable. Digital signals

This study evaluated the performance of different ventilation methods under varying limited space air stability conditions with respect to air distribution and pollutant transport in a space capsule. Two ventilation methods were adopted: mixing ventilation (MV) and displacement ventilation (DV). A seated thermal manikin was centred in a computational domain representing the capsule in order to simulate

The liquid-liquid interface evolution characteristic during droplets coalescence in the surrounding liquid is numerically studied taking no account of the influence of the gravity. The influences of viscosity ratio of internal and external fluids as well as the relative size and Oh number of the droplets on the coalescence process are analyzed. The results show that, three coalescence types are indicated

The problem of natural convection of a viscous incompressible fluid between two concentric cylinders is investigated. It is assumed that the inner cylinder can rotate around its axis without friction. Convection in the area is created due to the constant temperature difference at the outer boundary. The movement of fluid in the annular cavity, due to viscous friction, will cause the rotation of the

Liquid sloshing in storage tanks is of critical concern for the fluid management in space. In the present study, oscillation of liquid in a partially filled capsule storage tank was numerically studied using the volume of fluid method and taking into account the dynamic contact angle. The filling ratios of tank ranging from 10% to 90% and the gravity levels of 10−3 g0 and 0 g0 were considered as the

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 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