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Prof. George H. Miley
local time: 2021-06-22 10:00 (-05:00 DST)
Prof. George H. Miley (Abstracts)
Titles Abstracts Details
  • Advanced NaBH4/H2O2 Fuel Cell for Space Applications (2009) [Updated 1 decade ago]

    Fuel cells have played an important role in NASA's space program starting with the Gemini space program. However, improved fuel cell performance will be needed to enable demanding future missions. An advanced fuel cell (FC) using liquid fuel and oxidizer is being developed by U of IL/ NPL team to provide air independence and to achieve higher power densities than normal H2/O2 fuel cells (Lou et al., 2008; Miley, 2007). Hydrogen peroxide (H2O2) is used in this FC directly at the cathode (Lou and Miley, 2004). Either of two types of reactant, namely a gas-phase hydrogen or an aqueous NaBH4 solution, is utilized as fuel at the anode. Experiments with both 10-W single cells and 500-W stacks demonstrate that the direct utilization of H2O2 and NaBH4 at the electrodes result in >30% higher voltage output compared to the ordinary H2/O2 FC (Miley, 2007). Further, the use of this combination of all liquid fuels provides - from an operational point of view - significant advantages (ease of storage, reduced pumping requirements, simplified heat removal). This design is inherently compact compared to other fuel cells that use gas phase reactants. This results in a high overall system (including fuel tanks, pumps and piping, waste heat radiator) power density. Further, work is in progress on a regenerative version which uses an electrical input, e.g. from power lines or a solar panel to regenerate reactants.

    Experimental results to date and design studies confirm the original motivation that this new type of fuel cell offers great potential for enabling aggressive next set missions. This type of fuel cell also has the advantage that it can scale over a wide range of powers. Thus, it becomes a viable candidate for use in satellites, for component power in spacecraft, rovers, and base power. Since the NaBH4 fuel can be shipped as a compact solid and mixed with a small amount of startup water (e.g. initial water from indigenous sources), additional operational water is recycled from that generated in the cell reactions. This conservation of water removes the need to transport water to the fuel cell greatly simplifying operational logistics. The fuel supply and water strategy will be discussed in detail in the presentation.

  • IEC Thrusters for Space Probe Applications and Propulsion (2009) [Updated 1 decade ago]

    Earlier conceptual design studies (Bussard, 1990; Miley et al., 1998; Burton et al., 2003) have described Inertial Electrostatic Confinement (IEC) fusion propulsion to provide a high-power density fusion propulsion system capable of aggressive deep space missions. However, this requires large multi-GW thrusters and a long term development program. As a first step towards this goal, a progression of near-term IEC thrusters, stating with a 1 -10 kWe electrically-driven IEC jet thruster for satellites are considered here. The initial electrically-powered unit uses a novel multi-jet plasma thruster based on spherical IEC technology with electrical input power from a solar panel. In this spherical configuration, Xe ions are generated and accelerated towards the center of double concentric spherical grids. An electrostatic potential well structure is created in the central region, providing ion trapping. Several enlarged grid opening extract intense quasi-neutral plasma jets. A variable specific impulse in the range of 1000-4000 seconds is achieved by adjusting the grid potential. This design provides high maneuverability for satellite and small space probe operations. The multiple jets, combined with gimbaled auxiliary equipment, provide precision changes in thrust direction. The IEC electrical efficiency can match or exceed efficiencies of conventional Hall Current Thrusters (HCTs) while offering advantages such as reduced grid erosion (long life time), reduced propellant leakage losses (reduced fuel storage), and a very high power-to-weight ratio. The unit is ideally suited for probing missions. The primary propulsive jet enables delicate maneuvering close to an object. Then simply opening a second jet offset 180 degrees from the propulsion one provides a ?plasma analytic probe? for interrogation of the object.

    The technology underlying this electrically-driven jet unit leads naturally to a next generation fusion driven unit. For example, a low-Q version of one of the modules designed for the magnetically-channeled IEC trap array propulsion plant (Miley and Wu, 2007) could be used for next generation power units to replace current HCTs. These commonly generate 0.2 - 1.0 Newton's of thrust and 3-12 kWe for LEO or MEO to GEO orbit transfer as well as station keeping or orbit plane changes. The fusion IEC version offers major advances in system power density and eliminates use of increasingly scarce fuels like Xe. A feature of the IEC type fusion device is its non-Maxwellian operation, enabling use of advanced fuels such as the D-He employed in the Space Ship II design (Burton et al., 2003). p-B11, such as used in (Bussard, 1990), represents an ultimate goal. Such units would initially be for large orbiting satellites, and then scaled up for use as a power/propulsion unit for a manned Mars or beyond interplanetary spacecraft.

  • Condensed Matter Cluster Reactions in LENR Power Cells for a Radical New Type of Space Power Source (2009) [Updated 4 years ago]

    This paper reviews previous theoretical and experimental study on the possibility of nuclear events in multilayer thin film electrodes (Lipson et al, 2004 and 2005; Miley et al., 2007), including the correlation between excess heat and transmutations (Miley and Shrestha, 2003) and the cluster theory that predicts it. As a result of this added understanding of cluster reactions, a new class of electrodes is under development at the University of Illinois. These electrodes are designed to enhance cluster formation and subsequent reactions. Two approaches are under development. The first employs improved loading-unloading techniques, intending to obtain a higher volumetric density of sites favoring cluster formation. The second is designed to create nanostructures on the electrode where the cluster state is formed by electroless deposition of palladium on nickel microstructures. Power units employing these electrodes should offer unique advantages for space applications. This is a fundamental new nuclear energy source that is environmentally compatible with a minimum of radiation involvement, high specific power, very long lifetime, and scalable from micro power to kilowatts.

  • Emerging Physics For a Brerakthrough Thin-Film Electrolytic Cell Power Unit (1999) [Updated 1 decade ago]

    Electrolytic cell experiments are described using cathodes coated with thin metallic films (order of 500 A, using variously Ni, Pd and Ti) in a flowing packed-bed electrolytic cell producting - 1 W/cc excess power. Measurements of nuclear isotopes produced in the films suggest a nuclear reaction origin for the heat. The characteristic "signatures" of the isotope array observed in these experiments are discussed, along with speculations about the reaction physics involved.