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Experimental set-up render: 1) Ferrofluid container; 2) Copper coil; 3) Visualization system assembly; 4) Stepper engine; 5) Linear modules; 6) Servo locking mechanism. the free surface of the ferrofluid and relevant dynamical parameters are extracted.
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Ferrofluids are colloidal suspensions of magnetic nanoparticles in a carrier liquid. It is beneficial, for both fundamental research and future applications of ferrofluids in space, to obtain reliable measurements of the dynamics of ferrofluids in microgravity. This field remains unexplored since experiments in microgravity are expensive and the ac...
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... experimental set-up ( Fig. 1) is designed to impose an initial acceleration and magnetic field to a given ferrofluid volume and quantify the fluid response in microgravity. It consists of two linear sliding modules fixed to the capsule platform that hold two aluminium bases, each on which a plexiglass cylindrical container is mounted. The plexiglass containers ...
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The active deorbiting and passivation of launch vehicles has become key for the implementation of modern space debris mitigation guidelines. Appropriate engine restart conditions must be provided as part of this process. Ullage motors have been traditionally employed to induce active settling and ensure a gas-free propellant supply to the engines. Although robust and reliable, ullage rockets are also heavy, which motivates the study of alternative approaches to the problem. Classic propellant management devices could potentially be employed in this context, but they are hardly applicable to high flow rate cryogenic liquid systems. This paper explores several novel propellant settling strategies that are particularly well suited for cryogenic propellants. In particular, three distinct Magnetic Positive Positioning concepts, a hydrogen-peroxide-based Propellant Gasification System, and a hybrid device that combines both approaches are introduced. The preliminary technical analysis indicates that the successful development of these technologies could lead to mass savings of hundreds of kilograms and economic gains of several hundred thousand dollars per launch.
A coupled ferrohydrodynamic interface-tracking model is introduced for the analysis of the equilibrium, linear stability, and modal response of magnetic liquid interfaces in surface tension-dominated axisymmetric multiphase flows. The incompressible viscous mass and momentum balances are solved together with the steady-state Maxwell equations by following a monolithic solution scheme. The method is fully implicit, allowing to reach a steady-state solution in a single time step. In addition, the time-dependent evolution of the interface subject to variable external inputs can also be simulated. The geometry is particularized for the study of the free surface oscillations of a ferrofluid in a cylindrical tank under the influence of an inhomogeneous magnetic field in microgravity. Five regions are used to discretize the simulation domain, which combines analytical and elliptic mappings. Magnetic field-free results are validated by the literature. The modal response of the fluid-magnetic system agrees with measurements from the European Space Agency (ESA) Drop Your Thesis! 2017 The Ferros experiment and improves previous quasi-analytical estimations. This new framework of analysis can be applied to the study of a wide variety of microfluidic and low-gravity fluid systems.
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The advancement of smart materials has substantially affected the sample preparation techniques. Recently, different smart materials like carbon‐based materials, magnetic nanoparticles, and ferrofluids have been used to separate analytes from different matrices. Among these, ferrofluids have attracted considerable attention due to their liquidity and magnetic controllability, facilitating their recovery during the extraction process. Ferrofluids are dispersions of magnetic powders in a carrier liquid with a great magnetic response. Ferrofluid can be moved with the help of positioning and strength of a magnetic field. So, the fluid can be positioned at the desired point very precisely. This review offers a comprehensive discussion of the modern trends in ferrofluid-based microextraction techniques from the introduction of ferrofluids as an extractant (2010) to 2020. Also, the challenges faced by each method have been investigated. This review details the essential factors in the synthesis of ferrofluids. Finally, the challenges and outlooks of ferrofluids are outlined.
[The final version of this work can be found at https://doi.org/10.1016/j.actaastro.2021.08.029 and https://doi.org/10.1016/j.actaastro.2021.07.020] Liquid level measurement devices are required in experimental sloshing research. Several techniques with different capabilities and degrees of complexity have been historically proposed to cover this need. This paper describes an inexpensive, non-invasive and highly adaptable surface reconstruction device for opaque liquids. The instrument was developed to study the lateral sloshing of ferrofluids in microgravity as part of the UNOOSA DropTES StELIUM project. Its design is driven by the highly demanding geometrical and mechanical constraints imposed by ZARM’s drop tower, where the experiment will be launched in November 2019. The device implements redundant procedures to measure the first three lateral sloshing frequencies and damping ratios of the liquid, as well as its equilibrium surface in microgravity. Ideal vertical resolutions of 0.4 mm/px can be achieved with the configuration here implemented. The actual performance depends, among other factors, on the application of a robust calibration procedure.
