Experimental Study on the Deflagration Characteristics of the Liquid Propellant Spray Electrical Ignition and the Simplified Model Calculation
The liquid propellant atomization experimental apparatus, single pulse discharge device and the AC (alternating current) sequence discharge device have been designed to explore the electrical ignition method of HANbased liquid propellant. By using of high speed camera system, the electrical ignition experiment study of the HAN-based liquid propellant LP1846 under different injection pressure has been conducted. The results indicate that: the spray can be ignited instantly by single pulse discharge method as the Sauter mean diameter of the LP1846 droplets is in the region of 10~20 μm, but there is deflagration ability; stable ignition can be got by alternating current pulse discharge method as SMD of LP1846 droplets is in the region of 40~50 μm . Based on the experiment, the simplified model of LP1846 atomization pulse discharge ignition delay time has been proposed. The numerical results coincide well with the experimental results.
NONTOXIC ORBITAL MANEUVERING AND REACTION CONTROL SYSTEMS FOR REUSABLE SPACECRAFT
Toxic propellants have a high ground operations cost because of the potential hazards that require extensive safety precautions, particularly for reusable spacecraft. Nontoxic propellants for orbital maneuvering and reaction control systems have received periodic attention since the late 1960s as new reusable vehicles and upgrades to existing vehicles are proposed. This paper discusses the spacecraft requirements that drive propellant selections, the viable candidates for nontoxic propellants, and the system concepts and technologies required. Options for nontoxic propellants are also discussed, which are categorized as monopropellants, storable bipropellants, and cryogenic oxygen-based bipropellants. Monopropellants provide inherently simple systems and are most suited to low total impulse systems. Hydrogen peroxide and kerosene is a promising storable bipropellant in terms of its density, specie c impulse, and low toxicity for long-duration spacecraft on-orbit propulsion systems. This combination can be made hypergolic, which renders it a very effective replacement for currently used storable propellants. The hypergolic characteristics of kerosene with additives and high-concentration hydrogen peroxide are presented in detail. Higher-performance liquid oxygen and alcohol or hydrocarbon fuels are advantageous for reusable propulsion systems that emphasize e uid commonality with other spacecraft systems and for human exploration missions where in-situ propellant production is foreseen. The prospects for further research work on all of these propellants are also discussed.
A Comprehensive Study of Methanol Kinetics in Freely-Propagating and Burner-Stabilized Flames, Flow and Static Reactors, and Shock Tubes
Abstract An experimental and numerical study of methanol kinetics has been conducted. A detailed kinetic scheme was compiled which closely predicts properties of mixtures of methanol, oxygen, and inert for a variety of experimental configurations and conditions. The scheme incorporates the most recent kinetic information and was tested against experimental data for the propagation speeds and structure of laminar flames as well as the species concentration evolutions in flow reactors, static reactors, and shock tubes. The laminar flame speeds of atmospheric methanol/air mixtures were determined using the counter-flow flame technique over extensive lean-to-rich fuel concentration ranges and for initial mixture temperatures ranging from 318 to 368 K., while the experimental data on the laminar flame structure and from reactors and shock tubes were obtained from the literature. The scheme compiled herein includes the detailed C1, C2, and methanol submechanisms and yields close agreement with all of the experi...