Microgravity Science and Technology

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The characteristics of a pre-flight model of the Skylab BMMD (Body Mass Measurement Device), which was made around 1970 by the team led by Dr. William Thornton, are accurately evaluated using an optical interferometer on ground. The calibration of the BMMD is conducted using metal block weights in the range of the total mass of 4.134 kg to 100.131 kg, in which the RMS value of the differences between the regression line and the calibrated values are 0.018 kg. Using this calibration result, the B...

On-orbit filling is one of the important technologies for long-period space exploration. Filling without moving components and with low mass loss has obvious advantage for on-orbit fillings, especially for small volume filling. For such purpose, a no-pump no-vent filling system was proposed, and the working principle of the filling and the criterion to end the filling in microgravity were equivalently verified on ground. In such filling system, two distinct filling phases were witnessed: a fast ...

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 of the control system. To accurately analyze these effects, a cusped field thruster is used in t...

Accuracy assessment of microaccelerations simulation on the spacecraft “Foton-M” no. 2 according to magnetic measuring instruments data

The accuracy of modeling the field of microaccelerations of the internal environment of the middle class spacecraft of the Foton type is evaluated. It is assumed that the data of onboard magnetic measuring instruments were used as initial data for modeling micro-accelerations. The analyzed spacecraft do not have large elastic elements. The assessment was performed taking into account the influence of the work of the target and supporting equipment on the accuracy of measuring the components of t...

Numerical Simulation on the Effects of Component Layout Orientation on the Performance of a Neon-Charged Cryogenic Loop Heat Pipe

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 (Ne-CLHP) experiment data, and a good agreement is achieved. The effect of gravity caused by di...

Modelling of Unidirectional Reciprocating Sliding Contacts of Nanoscale Textured Surfaces Considering the Impact Effects in Microgravity Environment

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 to the friction reduction. Considering the impact effects, the motion of a clearance joint is sim...

Effects of Nanoparticle Shapes on Heat and Mass Transfer of Nanofluid Thermocapillary Convection around a Gas Bubble

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 with spherical nanoparticles is the largest, which is followed by blade, brick, cylinder and p...

Analysis of Characteristics of Two-Layer Convective Flows with Diffusive Type Evaporation Based on Exact Solutions

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 additionally to describe vapor and heat transfer processes in the gas-vapor phase. The use o...

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 speed for various working conditions and the liquid volume below a specified cross section for va...

Modes of Thermogravitational Convection and Thermoelectrokinetic Instability Under Joule Heating in Electrolyte Between Electric Membranes

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–Benard convection, and a novel type of instability, the thermoelectrokinetic instability. Stability of a quiescent one-dimensional steady-state solution to infinite small sinusoidal perturbations has been investigated in a wide range of the Rayleigh numbers. It has been found that, for the both...

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