Re: Understanding Aerospace Chemical Propulsion Book Pdf
Macabeo Eastman
Electric Propulsion Systems typically use electric heating or electric or magnetic fields to accelerate propellants (usually gases). These systems can be very fuel-efficient but can only accelerate relatively few particles of gasses at a time, resulting in very tiny thrusts. Often, these are ideal engines for deep space exploration where transit times can be very long and rapid maneuvers are not required.
Chemical Propulsion Systems, on the other hand, uses chemical reactions to release energy and accelerate gases to generate thrust. These systems produce relatively large thrusts in relatively short periods of time. There are several kinds of chemical propulsion, including liquid/gaseous propulsion, solid propulsion, and hybrid propulsion. An example of liquid chemical propulsion is shown in the image above in the banner.
The Space Shuttle Orbiter and its big orange tank or the Saturn V rocket are examples of vehicles with cryogenic liquid propulsion systems. Liquid Propulsion systems can produce a wide range of thrust, can be controlled on and off, but often must be fueled and set up just prior to their launch. Also included with Liquid propulsion systems are Nuclear Thermal Systems, which typically use a nuclear reactor to thermally heat cryogenic hydrogen gas to very high temperatures before exhausting the hydrogen through a rocket nozzle.
Hybrid propellant systems are a combination of solid propellant systems and liquid propellant systems. Typically, there is a solid-propellant fuel but the oxidizer needed for combustion is kept separate as a liquid or gas. Only so long as the oxidizer is supplied over the solid propellant is there combustion and thrust. The advantages of this type of system is the high thrust of solid propellant systems combined with the controllability (on-off) of liquid propulsion systems.
Our research on chemical and thermal propulsion systems at Glenn Research Center primarily focuses on chemical propulsion systems, in all their forms and types, with the major emphasis on liquid propulsion systems. Our work supports the systems used for the Orion Service Module, Nuclear Thermal engine development, small monopropellant and bi-propellant thrusters for satellites and spacecraft, and propulsion systems for future NASA endeavors like the Artemis program to the Moon and beyond.
Our capabilities include studying engine performance (analysis), helping to design & build the next generation of engines (design and development) and running engines through a battery of tests (testing) to ensure they can meet the rigorous demands of spaceflight.
The NASA Glenn Research Center also supports and promotes research in advanced propulsion and propellants needed for chemical propulsion as well as other propulsion systems and a more thorough description of this work is described in Fuels and Space Propellants for Reusable Launch Vehicles. This research encompasses both air-breathing fuels and space flight rocket propulsion and propellants.
The Engineering and Complex Systems team within the Engineering and Information Science Branch leads the discovery and development of the fundamental and integrated science that advances future air and space flight. The broad goal of the team is to discover and exploit the critical fundamental science and knowledge that will shape the future of aerospace sciences. A key emphasis is the establishment of the foundations necessary to advance the integration or convergence of the scientific disciplines critical to maintaining technological superiority.
A wide range of fundamental research addressing electronics, fluid dynamics, materials, propulsion, and structural mechanics are brought together in an effort to increase performance and achieve unprecedented operational capability. The team carries out its ambitious mission through leadership of an international, highly diverse and multidisciplinary research community to discover, shape, and champion new scientific discoveries that will ensure novel innovations for the future U.S. Air Force.
The central research direction for this team focuses on meeting the basic research challenges related to future air and space flight by leading the discovery and development of fundamental science and engineering in the following research areas.
Program Description: The objective of this portfolio is to develop the fundamental scientific knowledge required to understand the dynamics of complex, heterogeneous and reactive materials for game-changing advancements in munitions and propulsion. The research areas supported by this portfolio therefore seek to discover, characterize, and reliably predict the fundamental chemistry, physics, hydrodynamics and materials science associated with the high energetics of explosives, solid propellant burning, and structural dynamics of materials subject to shock loading. The overall scope of the research in the portfolio will be accomplished through a balanced mixture of experimental, numerical, and theoretical efforts. The fundamental science of interest to this portfolio is necessary for revolutionary advances in future Air Force weapon systems and their propulsion capabilities, including increased energy density, operational efficiency, effect-based optimization, and survivability in harsh environments.
Basic Research Objectives: Research proposals are sought in all aspects of the chemistry and physics of energetic materials with particular emphasis on chemistry-microstructure relationships and the fundamental dynamics of heterogeneous materials with complex structural properties. The problems of interest span multiple time and length scales, and strongly couple a broad range of physical phenomena, presenting fundamental challenges in experimental characterization, data assimilation, and model development. Efforts that leverage recent breakthroughs in other scientific disciplines to foster rapid research advancements are also encouraged.
You are highly encouraged to contact our Program Officer prior to developing a full proposal to briefly discuss the current state-of-the-art, how your research would advance it, and the approximate cost for a three (3) to five (5) year effort.
Program Description: This program seeks scientific breakthroughs in materials, heterostructures, and devices that can lead to game-changing capabilities in RF sensing and amplification, transmit/receive functions, wideband operation, and novel functionalities. The primary frequencies of interest range from GHz to THz.
Basic Research Objectives: The focus of the portfolio is on understanding and exploiting fundamental interactions of electrons and quasiparticles with each other and their host materials in all regions of device operation. Technical challenges include understanding and controlling (1) interactions between particles/quasiparticles and host lattices, boundaries, and defects, including thermal effects and changes over time that limit lifetime and performance; (2) carrier velocity; and (3) methods of device operation that do not rely solely on conventional transistors or transport mechanisms such as drift, diffusion, and tunneling. Included are carrier transport and properties in regimes in which transport is not limited by scattering mechanisms, such as in topologically protected states. Efficiency, volume, speed, and power are important figures of merit. It is expected that to understand fully the various new phenomena and device configurations, novel techniques to study and control nanoscale structures, defects, and operations may be required. The program emphasizes experiments and also supports theory and modeling.
Proposers are highly encouraged to contact the Program Officer prior to developing a white paper or proposal, preferably by email, to discuss the current state of understanding, how your research would advance it, and the approximate cost of a three- to five-year effort.
Program Description: This portfolio addresses energy needs of Air Force aerospace systems for the propulsion and non-propulsive functions of increasingly significant energy requirements. The portfolio emphasizes three foundational elements: (1) Fundamental, (2 )Relevant, and (3) Game-Changing, i.e.: starting from establishing fundamental scientific understanding and quantifying rate-controlling processes, focusing on Air Force interests and relevant conditions, encouraging multi-disciplinary collaborations, interactions and unconventional and innovative thinking, leading to game-changing concepts and predictive capabilities for the Air Force
Combustion is the primary conversion process to supply energy for propulsion and other functions of aerospace systems such as planes, rockets, hypersonic and UAV systems. In these systems, the fuel combustion process occurs at highly turbulent flow conditions, governed by underlying molecular changes from high-energy states to lower ones, generating usable energy for system functions. The key turbulent combustion attributes are critical in determining operability, performance, size and weight of such systems. The understanding of these key attributes and the quantification of the inherent rate-controlling processes provide the scientific foundation of modeling/simulation capabilities needed for the design of new generations of AF aerospace systems. Based on recent progresses in understanding/modeling key chemical reaction pathways in combusting AF/DOD fuels and in exploring key attributes of turbulent flame structure and dynamics at relevant conditions, the turbulent combustion part of the portfolio currently focuses on exploring, understanding and qualifying the turbulent-chemistry interactions using physical and numerical experiments. This includes but is not limited to:
Thermodynamics provides insights into energy conversion processes and the foundation to developing potentially game-changing energy-conversion approaches. It also establishes the thermodynamic foundation and framework to analyze the energy requirement and efficiency of propulsion systems and non-propulsive subsystem functions of increasingly significant energy needs. The following topics are of particular interest:
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