No full-text available
To read the full-text of this research,
you can request a copy directly from the author.
Simulation of LOX reorientation using magnetic positive positioning
Abstract
A combination of both experimental and computational simulation results have recently provided strong evidence that magnetic
positioning may be a feasible alternative technology for managing cryogenic propellants onboard spacecraft. One prerequisite
in the assessment of magnetic propellant management is the ability of predicting propellant reorientation in full-scale propellant
tanks. A computational simulation is used to model magnetically induced liquid oxygen (LOX) flows in reduced gravity. Simulations
of magnetic positive positioning of LOX are presented and the influence of the magnetic field and background acceleration
on reorientation timing is explored. A dimensionless reorientation time is sought to compliment the magnetic Bond number and
Bond number as an additional predictive correlating parameter for scaling this process. Evidence is provided that supports
the continued use of these correlating parameters to predict the magnetic fields required to reorient cryogenic propellants
in full-scale spacecraft tanks. Further, this study supports the conclusion that magnetic positive positioning appears to
be a viable emerging technology for cryogenic propellant management systems that merits further computational investigation
and space-based experimentation to establish the technology base required for future spacecraft design.
... Such ferrofluids were selected to approximate the linear magnetization curve of liquid oxygen for different magnetic field intensities. Subsequent publications presented refined numerical models and numerical results of technical relevance [154,[164][165][166][167][168][169][170][171]. The axisymmetric and lateral sloshing of water-based ferrofluids was characterized in microgravity when subjected to an inhomogeneous magnetic field as part of the ESA Drop Your Thesis! 2017 [77,172,173] and UNOOSA DropTES 2019 [174][175][176][177] campaigns reported in Chapter 9. ...
... The complexity of the coupled fluid-magnetic problem described in Chapter 6 may suggest that an analytical approximation to low-gravity magnetohydrodynamics is totally unfeasible. Indeed, previous works in the field rely heavily on numerical simulation frameworks [154,[163][164][165][166][167][168][169][170][171], somehow renouncing to more classical methods. This chapter shows that an analytical approach to the study of capillary, magnetic liquid interfaces is not only feasible, but also convenient. ...
... Although this problem has been comprehensively studied since the Apollo era, its magnetic equivalent remains practically unexplored. Exceptions are the numerical works by Marchetta and coworkers [154,[165][166][167][168][169][170][171] where the magnetic field is computed or measured as a fixed external input. ...
The commercialization of the sub-orbital environment, the ambition to make humans a multi-planetary species, and the urgent need for sustainable space operations are driving the development of a new generation of space systems. The use of electromagnetic forces (and electromagnetism, in general) is proposed in this dissertation to enable mid-distance, contactless actuation and sensing for space technology development. Following this paradigm, two applications are explored: electron-based touchless spacecraft potential sensing, and low-gravity magnetohydrodynamics.
The electron-based touchless potential sensing method was recently introduced to characterize the electrostatic state of non-cooperative objects in GEO and deep space. Applications span from arcing prevention to space debris removal. Although the fundamentals of this approach were studied in previous works, several open questions remained regarding the effect of complex geometries and differential charging on the sensing process. Such questions are here addressed with efficient numerical tools and vacuum chamber experiments, providing key insights into the behavior of realistic spacecraft formations. In addition, new active photoelectron-based sensing strategies are proposed that overcome some of the challenges of previous implementations.
The concept of low-gravity magnetohydrodynamics is also introduced as a way to actuate low-gravity fluid mechanics systems using magnetic forces. The theoretical foundations of the field are established from the analytical, numerical, and experimental perspectives with particular attention to the equilibrium, stability, and modal response of gas-liquid interfaces. Specific features of bubbles and droplets are also explored. Finally, the use of magnetic polarization and Lorentz forces in low-gravity fluid systems is discussed together with some of their applications, which include phase separation, magnetic positive positioning, and low-gravity electrolysis. The development of such technologies is initiated with support from microgravity research campaigns at ZARM's drop tower and Blue Origin's New Shepard suborbital rocket.
... A relevant work in this field is the NASA Magnetically Actuated Propellant Orientation (MAPO) experiment, that studied the magnetic positioning of liquid oxygen through a series of parabolic flight experiments with ferrofluids (Martin and Holt 2000). Subsequent contributions employed these results to validate numerical models and study the liquid reorientation dynamics (Hochstein et al. 1997;Marchetta andHochstein 1999, 2000;Marchetta et al. 2002;Marchetta 2006;Marchetta andRoos 2007, 2008;Marchetta and Winter 2010). ...
... A relevant work in this field is the NASA Magnetically Actuated Propellant Orientation (MAPO) experiment, that studied the magnetic positioning of liquid oxygen through a series of parabolic flight experiments with ferrofluids (Martin and Holt 2000). Subsequent contributions employed these results to validate numerical models and study the liquid reorientation dynamics (Hochstein et al. 1997;Marchetta andHochstein 1999, 2000;Marchetta et al. 2002;Marchetta 2006;Marchetta andRoos 2007, 2008;Marchetta and Winter 2010). ...
... A relevant work in this field is the NASA Magnetically Actuated Propellant Orientation (MAPO) experiment, that studied the magnetic positioning of liquid oxygen through a series of parabolic flight experiments with ferrofluids (Martin and Holt 2000). Subsequent contributions employed these results to validate numerical models and study the liquid reorientation dynamics (Hochstein et al. 1997;Marchetta andHochstein 1999, 2000;Marchetta et al. 2002;Marchetta 2006;Marchetta andRoos 2007, 2008;Marchetta and Winter 2010). ...
The sloshing of liquids in low-gravity entails several technical challenges for spacecraft designers due to its effects on the dynamics and operation of space vehicles. Magnetic settling forces may be employed to position a susceptible liquid and address these issues. Although proposed in the early 1960s, this approach remains largely unexplored. In this paper, the equilibrium meniscus and axisymmetric oscillations of a ferrofluid solution in a cylindrical tank are studied for the first time while subject to a static inhomogeneous magnetic field in microgravity. Coupled fluid-magnetic simulations from a recently developed inviscid magnetic sloshing model are compared with measurements collected at ZARM's drop tower during the ESA Drop Your Thesis! 2017 campaign. The importance of the fluid-magnetic interaction is explored by means of an alternative uncoupled framework for diluted magnetic solutions. The coupled model shows a better agreement with experimental results in the determination of the magnetic deformation trend of the meniscus, but the uncoupled framework gives a better prediction of the magnetic frequency response which finds no theoretical justification. Although larger datasets are required to perform a robust point-by-point validation, these results hint at the existence of unmodeled physical effects in the system.
... Motivated by the advent of stronger permanent magnets and high-temperature superconductors, the NASA MAPO experiment validated the magnetic positioning of liquid oxygen in a series of parabolic flights in 2001 [6]. Subsequent publications present refined numerical models and numerical results of technical relevance [16][17][18][19][20][21][22][23][24]. The axisymmetric sloshing of water-based ferrofluids was characterized in microgravity when subjected to an inhomogeneous magnetic field as part of the ESA Drop Your Thesis! 2017 campaign [25][26][27]. ...
... This is an important parameter for space applications due to its capacity of establishing an upper disturbance limit and driving the design of the liquid management system [2,3]. The dependence of * with the filling ratio [18], of the reorientation time with , and of the critical Bond number with [19,20,23] were explored for the NASA MAPO tank by Marchetta and coworkers. Subsequent models extend the computational model to non-linearly magnetized materials and complex magnetic setups [24]. ...
... The pioneering contributions by Marchetta and Hochstein made extensive use of numerical models to study the reorientation of magnetic liquids [16][17][18][19][20][21][22]24]. However, the authors did not explore the behavior of non-cylindrical Table 1 Physical properties of 4 (l) enriched with a 0.53% volume of 3 4 nanoparticles, and of 2 (l) at cryogenic storage temperature [41][42][43][44]. ...
The sloshing of liquids in low-gravity entails several technical challenges for spacecraft designers and operators. Those include the generation of significant attitude disturbances, the uncontrolled displacement of the center of mass of the vehicle or the production of gas bubbles, among others. Magnetic fields can be used to induce the reorientation of magnetically susceptible propellants and improve the controllability of a fluid system. Despite being proposed in the early 1960s, this approach remains largely unexplored. This paper provides new insight into the prospects and challenges of using magnetic control of space propellants. Key unanswered theoretical and technical questions are identified, highlighting the importance of developing appropriate analytical tools and fluid-magnetic simulation frameworks. New results associated with the reachability, scaling, long-term thermal and radiation stability, and efficiency of paramagnetic and ferromagnetic propellants are presented. Magnetic settling forces are shown to enhance the stability and speed up the oscillatory response of the liquid, leading to more predictable propellant management systems for different scales and filling ratios. These effects are particularly relevant for ferrofluids, whose enhanced magnetic properties make them excellent candidates for active sloshing control applications in space.
... Motivated by the advent of stronger permanent magnets and high-temperature superconductors, the NASA MAPO experiment validated the magnetic positioning of liquid oxygen in a series of parabolic flights in 2001 [6]. Subsequent works present refined numerical models and results of technical relevance [17][18][19][20][21][22][23][24][25]. The axisymmetric sloshing of water-based ferrofluids was characterized in microgravity when subjected to an inhomogeneous magnetic field as part of the ESA Drop Your Thesis! 2017 campaign [26][27][28][29]. ...
... Most existing works assume that the fluid-magnetic problem described by the MP 2 concept can be studied with a set of uncoupled fluid-magnetic equations [6,[16][17][18][19][20][21][22][23][24][25]. This is appropriate for lowsusceptibility fluids, such as liquid oxygen or liquid hydrogen. ...
The term sloshing refers to the movement of liquids in partially filled containers. Low-gravity sloshing plays an important role in the configuration of space vehicles, as it affects their dynamics and complicates the propellant management system design. Magnetic forces can be used to position a susceptible fluid, tune its natural frequencies, and increase its damping ratios in low-gravity. However, prior work shows that the analysis of this phenomenon, named magnetic liquid sloshing, requires advanced modeling capabilities. This paper introduces a coupled magnetohydrodynamic (MHD) model for the study of low-gravity axisymmetric magnetic liquid oscillations. 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. Five regions are used to discretize the simulation domain, that combines non-singular mappings and a meshfree approach. The steady-state solution (basic flow) is verified with equivalent computations from Comsol Multiphysics assuming the geometry and physical properties of the ESA Drop Your Thesis! 2017 drop tower experiment. Future steps include the study of linear oscillations, free surface stability properties, and lateral oscillations, among others.
... 15 Subsequent publications present refined numerical models to study this phenomenon. [16][17][18][19][20] The axisymmetric sloshing of water-based ferrofluids was characterized in microgravity when subjected to an inhomogeneous magnetic field as part of the ESA Drop Your Thesis! 2017 campaign. 21,22 As a follow-up, the lateral sloshing of ferrofluids was studied in the framework of the UNOOSA DropTES Programme 2019. ...
... 6 The passive MP 2 framework was explored with ferrofluids in the NASA MAPO experiment 15 and subsequent publications addressed applications for liquid oxygen and liquid hydrogen. [16][17][18][19][20] A magnetic source (e.g. a ring magnet) may be placed in the fuel outlet of a propellant tank to ensure a continuous gas-free supply to the engines. This would replace or complement the existing surface-tensionbased PMDs, which add inert mass to the system and complicate numerical analysis. ...
[The final version of this paper can be found in https://doi.org/10.1016/j.actaastro.2021.06.045]
The sloshing of liquids in low-gravity entails several technical challenges for spacecraft designers and operators. Those include the generation of significant attitude disturbances, the uncontrolled displacement of the center of mass of the vehicle or the production of gas bubbles, among others. Magnetic fields can be used to control the position of a magnetically susceptible propellant and transform a highly stochastic fluid system (non-linear sloshing) into a deterministic problem (linear sloshing). The employment of magnetic settling forces also produces an increase of the natural sloshing frequencies and damping ratios of the liquid. Despite being proposed in the early 1960s, this approach remains largely unexplored. A recently developed magnetic sloshing control model is here presented and extended, and potential space applications are explored. Technical challenges associated with the reachability, scaling and stability of paramagnetic and ferromagnetic systems are discussed, unveiling a roadmap for the implementation of this technology.
... It should be noted that LOX is the most susceptible natural paramagnetic liquid [45], making it particularly appropriate for this application. Subsequent publications by Marchetta and coworkers presented refined numerical models and results of technical relevance for the development of liquid oxygen magnetic positioning devices [46][47][48][49][50][51][52][53][54]. Recent works have also explored the free surface oscillations of ferrofluids in microgravity, which may be relevant for slosh control and the development of novel PMDs [55][56][57][58][59][60]. ...
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.
... In an attempt to address this problem, Papell invented ferrofluids, defined as colloidal suspensions of magnetic nanoparticles in a carrier liquid, in the early 1960s [49]. Although the idea of using magnetic liquids for slosh control remained dormant for decades, it has been revisited several times since the late 1990s [50][51][52][53][54][55][56][57][58][59]. A quasi-analytical model was recently introduced to study the equilibrium and modal response of ferrofluid interfaces in microgravity [22]. ...
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.
Copyright by Elsevier. Downloaded papers are for personal use only, and are not to be sold in any way or included in any commercial package.
... Even though low-gravity liquid sloshing and its interactions with spacecraft dynamics continue to be very active fields of research [20-26] and a number of publications have explored the magnetic positioning of liquid oxygen and low-susceptibility ferrofluids in microgravity [27][28][29][30][31][32][33][34][35], the study of highly susceptible ferrofluids for space applications ...
... Subsequent publications by Marchetta and coworkers presented refined numerical models and results of technical relevance for the development of liquid oxygen magnetic positioning devices. [35][36][37][38][39][40][41][42][43] Recent works have also explored the free surface oscillations of ferrofluids in microgravity, which may be relevant for slosh control and the development of novel propellant management devices (PMDs). [44][45][46][47][48][49] A comprehensive review of the field can be found in Ref. 19. ...
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. This paper explores for the first time several high-risk-high-return propellant settling strategies that may result in significant benefits for future space systems. 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 feasibility analysis indicates that the successful development of these technologies may lead to mass savings of hundreds of kilograms and economic gains of several hundred thousand dollars per launch. However, the robustness of some of these methods may be compromised by complex fluid-structure interactions that require a careful numerical and/or experimental analysis.
... This phenomenon is known as magnetic buoyancy and has been applied to terrestrial boiling experiments with ferrofluids [48,49]. Previous works on low-gravity magnetohydrodynamics have explored the diamagnetic manipulation of air bubbles in water [50,51], the positioning of diamagnetic materials [52], air-water separation [53], protein crystal growth [54], magnetic positive positioning [55][56][57][58][59], magnetic liquid sloshing [60,61], or combustion enhancement [51], among others. The application of Lorentz's force on liquid electrolytes has also been studied as a way to enhance hydrogen production [62][63][64][65][66][67][68][69][70][71][72]. ...
The management of fluids in space is complicated by the absence of relevant buoyancy forces. This raises significant technical issues for two-phase flow applications. Different approaches have been proposed and tested to induce phase separation in low-gravity; however, further efforts are still required to develop efficient, reliable, and safe devices. The employment of diamagnetic buoyancy is proposed as a complement or substitution of current methods, and as a way to induce the early detachment of gas bubbles from their nucleation surfaces. The governing magnetohydrodynamic equations describing two-phase flows in low-gravity are presented with a focus on bubble dynamics. Numerical simulations are employed to demonstrate the reachability of current magnets under different configurations, compare diamagnetic and Lorentz forces on alkaline electrolytes, and suggest scaling up procedures. The results support the employment of new-generation centimeter-scale neodymium magnets for electrolysis, boiling, and phase separation technologies in space, that would benefit from reduced complexity, mass, and power requirements.
... This phenomenon is known as magnetic buoyancy and has been applied to terrestrial boiling experiments with ferrofluids [31,32]. Previous works on low-gravity magnetohydrodynamics have explored the diamagnetic manipulation of air bubbles in water [33,34], the positioning of diamagnetic materials [35], air-water separation [36], protein crystal growth [37], magnetic positive positioning [38][39][40][41][42], magnetic liquid sloshing [43,44], or combustion enhancement [34], among others. The application of Lorentz's force on liquid electrolytes has also been studied as a way to enhance hydrogen production [45][46][47][48][49][50][51][52][53][54][55]. ...
[The final version of this paper can be found in http://arc.aiaa.org/doi/abs/10.2514/1.A35021]
The management of fluids in space is complicated by the absence of strong buoyancy forces. This raises significant technical issues for two-phase flows applications, such as water electrolysis or boiling. Different approaches have been proposed and tested to induce phase separation in low-gravity; however, further efforts are still required to develop efficient, reliable, and safe devices. The employment of magnetic buoyancy is proposed as a complement or substitution of current methods, and as a way to induce the early detachment of gas bubbles from their nucleation surfaces. The governing magnetohydrodynamic equations describing incompressible two-phase flows subjected to static magnetic fields in low-gravity are presented, and numerical simulations are employed to demonstrate the reachability of current magnets under different configurations. The results support the employment of new-generation neodymium magnets for centimeter-scale electrolysis and phase separation technologies in space, that would benefit from reduced complexity, mass, and power requirements.
... Low-gravity sloshing is characterized by its highly stochastic and unpredictable dynamics, which results in a complicated propellant management system design and a complex impact on the attitude control system of the spacecraft. Moreover, propellant management devices increase the inert mass of the vehicle and present long-term reliability issues with cryogens [6,7]. ...
Liquid sloshing represents a major challenge for the design and operation of space vehicles. In low-gravity environments, a highly non-linear movement can be produced due to the lack of stabilizing forces. This gives rise to significant disturbances that impact on the propulsion and attitude control systems of the spacecraft. The employment of magnetically susceptible fluids may open an interesting avenue to address this problem, but their dynamics in low gravity remain practically unexplored. The UNOOSA DropTES StELIUM project aims at filling this gap by studying the lateral sloshing of a ferrofluid solution subjected to an inhomogeneous magnetic field in microgravity. This paper describes the design process, challenges and preliminary results of the experiment, which was successfully launched at ZARM's drop tower in November 2019. The outcomes will be employed to validate the quasi-analytical models developed by the authors and set the path for the design of magnetic propellant positioning devices in space.
... Currently, there are several aspects of the inspace cryogenic fluid management (CFM) process that are in need of technology development such as storage, transfer and gauging of the propellant. Recent developments have occurred in measurements and modeling of volume and mass gauging (Marchetta 2006;Fu et al. 2013;Nishizu et al. 2006;Kulev and Dreyer 2010;Zimmerli et al. 2011) and propellant storage (Dhir et al. 2012) (Johnson et al. 2008). This paper focuses on the propellant transfer aspect of CFM. ...
The purpose of a liquid acquisition device (LAD) is to separate liquid and vapor phases inside a spacecraft propellant storage tank in the reduced gravity and microgravity conditions of space so that vapor-free liquid can be extracted to the transfer line. A popular type of LAD called a screen channel LAD or gallery arm, uses a fine porous screen and surface tension forces of the liquid to allow pure liquid to flow through the screen while blocking vapor penetration. To analyze, size, and optimize the design of LADs for future in-space propellant transfer systems, models and data are required for the four fundamental influential factors for LAD systems, including bubble point, flow-through-screen pressure drop, wicking rate, and screen compliance for a wide variety of screen meshes. While there is sporadic data available for three of these parameters, there is no published quantitative data for screen compliance. During the transient startup of propellant transfer, the liquid must be accelerated from rest to the steady flow demand velocity, which causes the screen to deform or comply, so compliance data is required for accurate transient LAD analyses; most design codes only consider steady state analysis. This paper presents screen compliance experiments on 14 different screens, examining the effects of fineness of mesh, open area, and screen metal type on compliance. A basic equation of state is also developed and validated against the data which can be easily integrated into any transient LAD flow code to model propellant transfer.
... propellants, but requires a large rotating structure which presents additional rendezvous and docking challenges. Another concept uses strong permanent magnets or electromagnets to force the liquid within the tanks to assume desired orientations [61][62][63]. Since LO 2 is paramagnetic and LH 2 are slightly diamagnetic, a strong magnetic field can influence the fluids to behave accordingly. ...
The 2010 National Space Policy of the United State of America introduced by President Obama directed NASA to set far reaching exploration milestones that included a crewed mission to a Near Earth Asteroid by 2025 and a crewed mission to Martian orbit by the mid-2030s. The policy was directly influenced by the recommendations of the 2009 Review of United States Human Space Flight Plans Committee, which called for an evolutionary approach to human space exploration and emphasized the criticality of budgetary, programmatic, and program sustainability. One potential method of improving the sustainability of exploration architectures is the utilization of orbital propellant depots with commercial launch services.
In any exploration architecture, upwards of seventy percent of the mass required in orbit is propellant. A propellant depot based architecture allows propellant to be delivered in small increments using existing commercial launch vehicles, but will require three to five times the number of launches as compared to the using the NASA planned 70 to 130 metric ton heavy lift launch system. Past studies have shown that the utilization of propellant depots in exploration architectures have the potential of providing the sustainability that the Review of United States Human Space Flight Plans Committee emphasized. However, there is a lack of comprehensive analysis to determine the feasibility of propellant depots within the framework of human space exploration.
The objective of this research is to measure the feasibility of a propellant depot and commercial launch based exploration architecture by stochastic assessment of technical, reliability, and economic risks. A propellant depot thermal model was developed to analyze the effectiveness of various thermal management systems, determine their optimal configuration, quantify the uncertainties in the system models, and stochastically compute the performance feasibility of the propellant depot system. Probabilistic cost analysis captured the uncertainty in the development cost of propellant depots and the fluctuation of commercial launch prices, and, along with the cost of launch failures, provided a metric for determining economic feasibility. Probabilistic reliability assessments using the launch schedule, launch reliability, and architecture requirements of each phase of the mission established launch success feasibility. Finally, an integrated stochastic optimization was performed to determine the feasibility of the exploration architecture.
The final product of this research is an evaluation of propellant depots and commercial launch services as a practical method to achieving economic sustainability for human space exploration. A method for architecture feasibility assessment is demonstrated using stochastic system metrics and applied in the evaluation of technical, economic, and reliability feasibility of orbital propellant depots and commercial launch based exploration architectures. The results of the analysis showed the propellant depots based architectures to be technically feasible using current commercial launch vehicles, economically feasible for having a program budget less than $4 billion per year, and have launch reliability approaching the best single launch vehicle, Delta IV, with the use of redundant vehicles. These results serve to provide recommendations on the use of propellant depots in exploration architectures to the Moon, Near Earth Objects, Mars, and beyond.
... There have been some small experiments such as MAPO 16 , which have been flown on the NASA zero-gravity airplane (Vomit Comet). Coupled fluid/electromagnetic models were correlated to the experimental results 17,18,19 . Analytical work has begun this year using those models to determine the feasibility of using magnetic propellant positioning for tanks on the scale required for propellant depots. ...
Orbital cryogenic propellant depots and the ability to refuel spacecraft in orbit are critical capabilities for the expansion of human life throughout the Solar System. While depots have long been recognized as an important component of large-scale manned spaceflight efforts, questions about their technology readiness have so far prevented their implementation. Technological advancements in settled cryogenic handling, passive thermal control systems, and autonomous rendezvous and docking techniques make near-term implementation of cryogenic propellant depots significantly more realistic. Current work on flight-demonstration tools like ULA's CRYOTE testbed, and Masten Space Systems's XA-1.0 suborbital RLV provide methods for affordably retiring the remaining technical risks for cryogenic depots. Recent depot design concepts, built on high-TRL technologies and existing flight vehicle hardware, can enable easier implementation of first-generation propellant depots without requiring extensive development programs. Some concepts proposed by industry include disposable "pre-depots", single-fluid simple depots, self-deployable dual-fluid single-launch depots using existing launchers and near-term launcher upgrades, and multi-launch modular depots. These concepts, particularly the dual-fluid single-launch depot enable robust exploration and commercial transportation throughout the inner Solar System, without the need for HLVs, while providing badly-needed markets to encourage the commercial development of more affordable access to space.
We present the RIPPLE computer program* for modeling transient, two-dimensional, incompressible fluid flows with surface tension on free surfaces of general topology. Finite difference solutions to the incompressible Navier-Stokes equations are obtained on an Eulerian, rectilinear mesh in Cartesian or cylindrical geometries. Free surfaces are represented with volume-of-fluid (VOF) data on the mesh. Surface tension is modeled as a volume force derived from the continuum surface force ( CSF) model. A two-step projection method is used for the incompressible fluid flow solutions, aided by an incomplete Cholesky conjugate gradient (ICCG) solution technique for the pressure Poisson equation (PPE). Momentum advection is estimated with the weakly monotonic, second order upwind method of van Leer. Flow obstacles and curved boundaries interior to the mesh are represented with a partial cell treatment. The improvements and enhancements of RIPPLE relative to its predecessor, NASA-VOF2D, have resulted in a versatile tool capable of modeling a wide range of applications, being especially suited for low-Bond number, low-Weber number, and low-Capillary number flows in which fluid accelerations are weak and fluid restoring forces (e.g., surface tensions) are strong. After a brief summary of the primary features of RIPPLE, we describe the model equations, the numerical method, and the structure of the computer program. Example calculations then illustrate the method's properties, with instructions given on the use of the program.
The impulsive propellant reorientation process is modeled using the Energy Calculations for Liquid Propellants in a Space Environment (ECLIPSE) code. A brief description of the process and the computational model is presented. Code validation is documented via comparison to experimentally derived data for small scale tanks. Predictions of reorientation performance are presented for two tanks designed for use in flight experiments and for a proposed full scale OTV tank. A new dimensionless parameter is developed to correlate reorientation performance in geometrically similar tanks. Its success is demonstrated.
A new method for modeling surface tension effects on fluid motion has been developed. Interfaces between fluids of different properties, or "colors", are represented as transition regions of finite thickness, across which the color variable varies continuously. At each point in the transition region, a force density is defined which is proportional to the curvature of the surface of constant color at that point. It is normalized so that the conventional description of surface tension on an interface is recovered when the ratio of local transition region thickness to local radius of curvature approaches zero. The continuum method eliminates the need for interface reconstruction, simplifies the calculation of surface tension, enables accurate modeling of two- and three-dimensional fluid flows driven by surface forces, and does not impose any modeling restrictions on the number, complexity, or dynamic evolution of fluid interfaces having surface tension. Computational results for two-dimensional flows are given to illustrate the properties of the method.
A series of experiments have been performed investigating the use of magnets to orient fluids in a lowgravity environment. The fluid of interest for this project was liquid oxygen (LO2) since it exhibits a paramagnetic behavior (is attracted to magnetic fields). However, due to safety and handling concerns, a water-based ferromagnetic mixture (produced by Ferrofluidics Corporation) was selected to simplify procedures. Three ferromagnetic fluid mixture strengths and a nonmagnetic water baseline were tested using three different initial fluid positions with respect to the magnet. Experiment accelerometer data were used with a modified computational fluid dynamics code (CFD) termed CFX-4 (by AEA Technologies) to predict fluid motion. These predictions compared favorably with experiment video data, verifying the code's ability to predict fluid motion with and without magnetic influences. Additional predictions were generated for LO2 with the same conditions and geometries used in the flight-testing. Test hardware consisted of a cylindrical Plexiglas tank (6-in. bore with 10-in. length), a 6,000-Gauss rare Earth ringmagnet, three-axis accelerometer package, computer, and a video recorder system. All tests were conducted aboard the NASA Reduced-Gravity Workshop, a KC-135 aircraft.
A finite-volume based computational model is developed to predict Marangoni convection in a cavity with a curved and deforming free surface. The two-dimensional incompressible continuity, momentum, and energy equations are solved on a staggered Cartesian grid. The free surface location is computed using the volume-of-fluid transport equation. Normal and tangential boundary conditions at the free surface are modeled using respectively a surface pressure and a continuum surface force technique. Computational predictions of thermocapillary flow in a shallow cavity are shown to be in good agreement with previously published asymptotic results. The new transient model is then used to study the influence of Marangoni number and Capillary number on thermocapillary flows in a cavity for different static contact angles. The flows are characterized by streamline and isotherm patterns. The influence of the dimensionless parameters on heat transfer rate at the cavity walls is exposed by examination of local Nusselt number profiles.
We present the NASA-VOF2D two-dimensional, transient, free-surface
hydrodynamics program. It has a variety of options that provide
capabilities for a wide range of applications, and it is designed to be
relatively easy to use. It is based on the fractional volume-of-fluid
method, and allows multiple free surfaces with surface tension and wall
adhesion. It also has a partial cell treatment that allows curved
boundaries and internal obstacles. This report includes a discussion of
the numerical method, a code listing, and a selection of sample
problems.
The free surface behaviour of a volatile wetting liquid at low gravity is studied using scaling and numerical techniques. An open cavity model, which was applied in part 1 to investigate fluid flow and heat transfer in non-deforming pores, is used to evaluate the influence of convection on surface morphology with length scales and subcooling/superheating limits of 1 [less-than-or-equal] D [less-than-or-equal] 102 μm and [similar] 1 K, respectively. Results show that the menisci shapes of highly wetting fluids are sensitive to thermocapillary flow and to a lesser extent the recoil force associated with evaporation and condensation. With subcooling, thermocapillarity produces a suction about the pore centreline that promotes loss of mechanical equilibrium, while condensation exerts an opposing force that under some conditions offsets this destabilizing influence. With superheating, thermocapillarity and evaporation act in the same direction and mutually foster surface stability. All of these trends are magnified by high capillary and Biot numbers, and the stronger circulation intensities associated with small contact angles. These phenomena strongly depend on the thermal and interfacial equilibrium between the liquid and vapour, and have important ramifications for systems designed to maintain a pressure differential across a porous surface.
Axisymmetric shapes and stability of nonlinearly polarizable dielectric (ferrofluid) drops of fixed volume which are pendant/sessile on one plate of a parallel-plate capacitor and are subjected to an applied electric (magnetic) field are determined by solving simultaneously the free boundary problem comprised of the Young-Laplace equation for drop shape and the Maxwell equations for electric (magnetic) field distribution. Motivated by the desire to explain certain experiments with ferrofluids, a constitutive relation often used to describe the variation of polarization with applied field strength is adopted here to close the set of equations that govern the distribution of electric field. Specifically, the nonlinear polarization, P, is described by a Langevin equation of the form P = α[coth (τE) −1/(τE)], where E is the electric field strength. As expected, the results show that nonlinearly polarizable drops behave similarly to linearly polarizable drops at low field strengths when drop deformations are small. However, it is demonstrated that at higher values of the field strength when drop deformations are substantial, nonlinearly polarizable supported drops whose contact lines are fixed, as well as ones whose contact angles are prescribed, display hysteresis in drop deformation over a wide range of values of the Langevin parameters α and τ. Indeed, properly accounting for the nonlinearity of the polarization improves the quantitative agreement between theory and the experiments of Bacri et
al. (1982) and Bacri & Salin (1982, 1983). Detailed examination of the electric fields inside nonlinearly polarizable supported drops reveals that they are very non-uniform, in contrast to the nearly uniform fields usually found inside linearly polarizable drops.
The problem of steady motion and thermal behaviour of a volatile, wetting liquid in an open cavity under low gravity is defined and examined. The domain geometrically approximates a two-phase pore of liquid on a wicking structure surface, and consists of a 1 to 102 μu wide rectangular cavity bounded by a saturated vapour and liquid reservoir on its upper and lower surfaces, respectively. Thermal non-equilibrium and convection are established by symmetrically superheating or subcooling the pore boundaries by [similar] 1 K relative to the vapour. Numerical analyses show that although thermocapillary flow competes with interfacial phase change in dictating the circulation and flow structure, it tends to reinforce the convective effects of evaporation and condensation on surface temperature and heat transport. In addition, highly wetting fluids with curved menisci are characterized by greater circulation intensities and dynamic pressure gradients than a flat surface. The magnitude of these gradients suggests that the fixed menisci shapes assumed in this study are unrealistic, and that the influence of convection on surface morphology should be considered.
A set of hydrodynamic equations has been applied to processes occurring in non-conductive fluids placed into magnetic fields. The equations are valid for equilibrium magnetization within the framework of a continuous medium. The ranges of physical parameters have been evaluated for which magnetization of a fluid should be taken into account in problems concerning the determination of equilibrium forms, and flows and their stability. The conclusion has been drawn that magnetization of natural fluids in these problems must be taken into consideration for fluids in high (exceeding 1 T) magnetic fields. As examples, the solutions of several typical problems concerning the equilibrium surface of capillary fluids and their stability in external magnetic fields have been considered. Hydrodynamic effects related to magnetization of natural capillary fluids in high magnetic fields are studied with due regard for the above solutions. Hydrodynamic effects in para- and diamagnetic fluids have been studied and the common and distinctive features of these effects discussed.
A phenomenological treatment is given for the fluid dynamics and thermodynamics of strongly polarizable magnetic fluid continua in the presence of nonuniform magnetic fields. Examples of the fluids treated here have only recently been synthesized in the laboratory. It is found that vorticity may be generated by thermomagnetic interaction even in the absence of viscosity and this leads to the development of augmented Bernoulli relationships. An illustration of a free‐surface problem of static equilibrium is confirmed by experiment and information is obtained regarding a fluid's magnetic susceptibility. Another illustration elucidates the mechanism of an energy conversion technique. Finally, an analytical solution is found for the problem of source flow with heat addition in order to display the thermomagnetic and magnetomechanical effects attendant to simultaneous heat addition and fluid motion in the presence of a magnetic field.
An existing empirical analysis relating to the reorientation of liquids in cylindrical tanks due to propulsive settling in a low gravity environment was extended to include the effects of geyser formation in the Weber number range from 4 to 10. Estimates of the minimum velocity increment required to be imposed on the propellant tank to achieve liquid reorientation were made. The resulting Bond numbers, based on tank radius, were found to be in the range from 3 to 5, depending upon the initial liquid fill level, with higher Bond number required for high initial fill levels. The resulting Weber numbers, based on tank radius and the velocity of the liquid leading edge, were calculated to be in the range from 6.5 to 8.5 for cylindrical tanks having a fineness ratio of 2.0, with Weber numbers of somewhat greater values for longer cylindrical tanks. It, therefore, appeared to be advantageous to allow small geysers to form and then dissipate into the surface of the collected liquid in order to achieve the minimum velocity increment. The Bond numbers which defined the separation between regions in which geyser formation did and did not occur due to propulsive settling in a spherical tank configuration ranged from 2 to 9 depending upon the liquid fill level.
An experimental program was conducted to examine the liquid flow patterns that result from the axial jet mixing of ethanol in 10-centimeter-diameter cylindrical tanks in weightlessness. A convex hemispherically ended tank and two Centaur liquid-hydrogen-tank models were used for the study. Four distinct liquid flow patterns were observed to be a function of the tank geometry, the liquid-jet velocity, the volume of liquid in the tank, and the location of the tube from which the liquid jet exited.
This report details the results of a series of fluid motion experiments to investigate the use of magnets to orient fluids in a low-gravity environment. The fluid of interest for this project was liquid oxygen (LO2) since it exhibits a paramagnetic behavior (is attracted to magnetic fields). However, due to safety and handling concerns, a water-based ferromagnetic mixture (produced by Ferrofluidics Corporation) was selected to simplify procedures. Three ferromagnetic fluid mixture strengths and a nonmagnetic water baseline were tested using three different initial fluid positions with respect to the magnet. Experiment accelerometer data were used with a modified computational fluid dynamics code termed CFX-4 (by AEA Technologies) to predict fluid motion. These predictions compared favorably with experiment video data, verifying the code's ability to predict fluid motion with and without magnetic influences. Additional predictions were generated for LO2 with the same test conditions and geometries used in the testing. Test hardware consisted of a cylindrical Plexiglas tank (6-in. bore with 10-in. length), a 6,000-G rare Earth magnet (10-in. ring), three-axis accelerometer package, and a video recorder system. All tests were conducted aboard the NASA Reduced-Gravity Workshop, a KC-135A aircraft.
The non-linear magnetization characteristics of recently developed ferrofluids complicate studies of wave dynamics and stability. A general formulation of the incompressible ferrohydrodynamics of a ferrofluid with non-linear magnetization characteristics is presented, which distinguishes clearly between effects of inhomogeneities in the fluid properties and saturation effects from non-uniform fields. The formulation makes it clear that, with uniform and non-uniform fields, the magnetic coupling with homogeneous fluids is confined to interfaces; hence, it is a convenient representation for surface interactions.
Detailed attention is given to waves and instabilities on a planar interface between ferrofluids stressed by an arbitrarily directed magnetic field. The close connexion with related work in electrohydrodynamics is cited, and the effect of the non-linear magnetization characteristics on oscillation frequencies and conditions for instability is emphasized. The effects of non-uniform fields are investigated using quasi-one-dimensional models for the imposed fields in which either a perpendicular or a tangential imposed field varies in a direction perpendicular to the interface. Three experiments are reported which support the theoretical models and emphasize the interfacial dynamics as well as the stabilizing effects of a tangential magnetic field. The resonance frequencies of ferrohydrodynamic surface waves are measured as a function of magnetization, with fields imposed first perpendicular, and second tangential, to the unperturbed interface. In a third experiment the second configuration is augmented by a gradient in the imposed magnetic field to demonstrate the stabilization of a ferrofluid surface supported against gravity over air; the ferromagnetic stabilization of a Rayleigh-Taylor instability.
The use of pulsed thrust to optimize the propellant reorientation process is proposed. The ECLIPSE code is used to study the performance of pulsed reorientation in small-scale and full-scale propellant tanks. A dimensional analysis of the process is performed and the resulting dimensionless groups are used to present and correlate the computational predictions of reorientation performance. Based on the results obtained from this study, it is concluded that pulsed thrust reorientation seems to be a feasible technique for optimizing the propellant reorientation process across a wide range of spacecraft, for a variety of missions, for the entire duration of a mission, and with a minimum of hardware design and qualification.
Flow patterns predicted by a computational model of jet-induced geyser formation in a reduced gravity environment are presented and comparison is made to patterns predicted by experimentally based correlations. The configuration studied is an idealization of a forthcoming flight experiment to examine cryogenic propellant management issues. A transitional version of the ECLIPSE code used as a computational tool for the analyses is described. It is shown that computationally predicted flow patterns are in qualitative agreement with the correlation-based predictions, and some details of the predicted flow fields are given.
Dynamics and Stability of Ferrofluids: Surface Interactions Stability of an Axisymmetric Jet of Magnetizable Fluid Effect of Nonlinear Polarization on Shapes and Stability of Pendant and Sessile Drops in an Electric (Magnetic) Field
- R E Zelazo
- J R Melcher
- V G Boshtovoi
- M S Krakov
- O A Basaran
- F K Wohlhuter
Zelazo, R.E., Melcher, J.R., " Dynamics and Stability of Ferrofluids: Surface Interactions ", J. Fluid Mechanics, vol 39, p 1, 1969. 10 Boshtovoi, V.G., Krakov, M.S., " Stability of an Axisymmetric Jet of Magnetizable Fluid ", Translated for Z. Prik. Mekh. I Tekh Fiz., p 147, July -Aug. 1978. 11 Basaran, O.A., Wohlhuter, F.K., " Effect of Nonlinear Polarization on Shapes and Stability of Pendant and Sessile Drops in an Electric (Magnetic) Field ", J. Fluid Mechanics, vol 244, p 1, 1992.
Development of Expulsion and Orientation Systems for Advanced Liquid Rocket Propulsion Systems
- D Chipchak
Chipchak, D., " Development of Expulsion and Orientation Systems for Advanced Liquid Rocket Propulsion Systems, " USAF Technical Report RTD-TDR-63-1048, Contract AF04 (611)-8200, July 1963.
A Computational Model for Magnetically Actuated Propellant Orientation Capillary Hydrodynamic Effects in High Magnetic Fields
- R T Warren
- B M Berkovsky
- N N Smirnov
Warren, R. T., " A Computational Model for Magnetically Actuated Propellant Orientation, " Magisterial Thesis, University of Memphis, May, 1998. 21 Berkovsky, B.M., Smirnov, N.N., " Capillary Hydrodynamic Effects in High Magnetic Fields ", J. Fluid Mechanics, Vol 187, p 319, 1988. 22 Anderson, J.C., Magnetism and Magnetic Materials. Chapman and Hall Ltd. London: 1968. p 58.
A Computational Model of Magnetic Positive Positioning in Reduced Gravity
- J G Marchetta
- J I Hochstein
Marchetta J.G., Hochstein, J.I., " A Computational Model of Magnetic Positive Positioning in Reduced Gravity ", IAF Paper ST-99-W.210, Oct. 1999.
Numerical Vorticity Due to a Strongly Nonlinear Body Force Staggered Grid Representation
- R P Palmiter
Palmiter, R. P., " Numerical Vorticity Due to a Strongly Nonlinear Body Force Staggered Grid Representation, " AIAA Southeastern Regional Student Conference, April 1999 Microgravity sci. technol. XVIII-1 (2006) J. G. Marchetta: Foam Experiments in Parabolic Flights: Simulation of LOX Reorientation Using Magnetic Positive Positioning
A Computational Model for Magnetically Actuated Propellant Orientation
- R T Warren
Modeling of Impulsive Propellant Reorientation
- J I Hochstein
- A E Patag
- D J Andchato
- J.I. Hochstein
Stability of an Axisymmetric Jet of Magnetizable Fluid”, Translated for
- V G Boshtovoi
- M S Krakov
Magnetism and Magnetic Materials
- J C Anderson
- J.C. Anderson