Keiichi Hori

Bio: Keiichi Hori is an academic researcher from Japan Aerospace Exploration Agency. The author has contributed to research in topics: Propellant & Combustion. The author has an hindex of 14, co-authored 96 publications receiving 781 citations.

MEMS-Based Solid Propellant Rocket Array Thruster

Abstract: The prototype of a solid propellant rocket array thruster for simple attitude control of a 10 kg class micro-spacecraft was completed and tested. The prototype has 10×10 φ0.8 mm solid propellant micro-rockets arrayed at a pitch of 1.2 mm on a 20×22 mm substrate. To realize such a dense array of micro-rockets, each ignition heater is powered from the backside of the thruster through an electrical feedthrough which passes along a propellant cylinder wall. Boron/potassium nitrate propellant (NAB) is used with/without lead rhodanide/potassium chlorate/nitrocellulose ignition aid (RK). Impulse thrust was measured by a pendulum method in air. Ignition required electric power of at least 3–4 W with RK and 4–6 W without RK. Measured impulse thrusts were from 2×10−5 Ns to 3×10−4 Ns after the calculation of compensation for air dumping.

Test of B/Ti multilayer reactive igniters for a micro solid rocket array thruster☆

Abstract: In this study, reactive B/Ti multilayer igniters were investigated for the noncontact ignition of a micro solid rocket array thruster in vacuum. When current is supplied to the B/Ti multilayer igniter, the chemical reaction: 2B + Ti → TiB 2 + 1320 cal/g occurs, and sparkles are spread to a distance of several millimeters or more. The B/Ti multilayer igniters with three sizes were fabricated, and tested in six configurations of solid propellant. Although one rocket with ignition charge was ignited successfully, the noncontact ignition of the solid propellant was not achieved. However, the B/Ti multilayer igniters themselves generated small impulses of 10 −6 N s order, suggesting the possibility of self-propulsion.

HAN and ADN as liquid ionic monopropellants: Thermal and catalytic decomposition processes

Abstract: Binary HAN and ADN aqueous solutions have been synthesized, then thermally and catalytically decomposed. Binary HAN mixtures were prepared with different concentrations: 95, 80 and 60 wt.%. Whereas ADN solution contains are: 75, 60 and 50 wt.%. The candidate catalysts were prepared by impregnation of alumina doped by lanthanum oxide with active phase precursors: iridium for HAN and copper oxide for ADN and characterized by transmission electron microscopy, X-ray diffraction and chemisorption. The decomposition processes were followed by thermal analysis and a constant batch reactor. This work shows the essential effect of monopropellant concentrations to determine the best green propellants for industrial applications as reaction control systems. Moreover, HAN and ADN solutions are more efficient for catalytic decomposition due to the absence of stabilizer to inhibit catalysts. The (10%)Ir/Al 2 O 3 –La 2 O 3 + HAN 95% and the (10%)CuO/Al 2 O 3 –La 2 O 3 + ADN 75% associations show lower decomposition temperatures, larger reaction rates and leads to higher amount of gas phase products, giving the most efficient systems.

Nanoenergetic Materials for MEMS: A Review

Abstract: New energetic materials (EMs) are the key to great advances in microscale energy-demanding systems as actuation part, igniter, propulsion unit, and power. Nanoscale EMs (nEMs) particularly offer the promise of much higher energy densities, faster rate of energy release, greater stability, and more security (sensitivity to unwanted initiation). nEMs could therefore give response to microenergetics challenges. This paper provides a comprehensive review of current research activities in nEMs for microenergetics application. While thermodynamic calculations of flame temperature and reaction enthalpies are tools to choose desirable EMs, they are not sufficient for the choice of good material for microscale application where thermal losses are very penalizing. A strategy to select nEM is therefore proposed based on an analysis of the material diffusivity and heat of reaction. Finally, after a description of the different nEMs synthesis approaches, some guidelines for future investigations are provided.

Recent Advances on Nitrous Oxide (N2O) Decomposition over Non-Noble-Metal Oxide Catalysts: Catalytic Performance, Mechanistic Considerations, and Surface Chemistry Aspects

Abstract: Nitrous oxide (N2O) is the largest stratospheric-ozone-depleting substance, being concomitantly the third most potent greenhouse gas. The direct catalytic decomposition of N2O (deN2O process) is one of the most promising remediation technologies for N2O emissions abatement. Although noble metals (NMs)-based catalysts demonstrate satisfactory deN2O performance, their high cost and sensitivity to various effluent stream components (e.g., water vapor, oxygen) limit their widespread industrial applications. Hence, the development of NMs-free catalysts of low cost and satisfactory deN2O performance is of paramount importance. This survey appraises the recent advances, which have been reported since 2000, on N2O decomposition over non-noble-metal oxidic catalysts. Initially, a brief overview of N2O sources, environmental consequences, and remediation technologies is provided. The literature related to the deN2O process over NMs-free metal oxides (MOs) is categorized and critically discussed, as follows: (i) bar...

Solid propellant chemistry, combustion, and motor interior ballistics

Abstract: This volume brings together international scientists in the field of solid rocket propulsion. Thirty-nine papers present in-depth coverage on a wide range of topics including: advanced materials and non-traditional formulations; the chemical aspects of organic and inorganic components in relation to decomposition mechanisms, kinetics, combustion and modelling; safety issues, hazards and explosive characteristics; and experimental and computational interior ballistics research, including chemical information and the physics of the complex flow field.