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Liquid propellant rocket engine combustion instabilities, describing unsteady combustor flow by single nonlinear wave equation with stable and unstable finite amplitude limit cycles
Liquid propellant rocket engines have some unique applications for highly loaded oscillating-motion bearings operating at cryogenic temperatures and vacuum environment conditions. Among these are (1) thrust attitude control gimbal bearings that permit pivoting of the entire rocket engine and (2) bearings in the linkages of ducting bellows joints that articulate when the engine gimbals. The main rocket engines for first, second, and third stages of the Saturn vehicle have thrust vector control gimbals which use PTFE liner bearing materials and ducting linkage bearings using solid film dry lubricants, both to reduce friction and provide required wear life. Data on the frictional and wear characteristics of these materials, while operating under varying temperature and atmospheric pressure conditions, are presented. A discussion of the bearing designs for flexible bellows joint linkages is also presented.
Liquid rocket propellant engine exhaust plume flow field, discussing mathematical models for combustion chamber, throat region and nozzle
Vibration environment of liquid propellant rocket engines
Nonlinear combustion instability in liquid propellant rocket engines, describing nonsteady combustion process with aid of Crocco time-lag hypothesis
Nonlinear combustion instability in liquid propellant rocket engines, describing nonsteady combustion process with aid of Crocco time lag hypothesis
Nonlinear combustion instability in liquid propellant rocket engines, describing unsteady combustor flow with single wave equation
Plume flow field analysis for liquid propellant rocket engines
Liquid-Propellant Rocket Engines (LREs) are capable of on-command variable thrust or thrust modulation, an operability advantage that has been studied intermittently since the late 1930s. Throttleable LREs can be used for planetary entry and descent, space rendezvous, orbital maneuvering including orientation and stabilization in space, and hovering and hazard avoidance during planetary landing. Other applications have included control of aircraft rocket engines, limiting of vehicle acceleration or velocity using retrograde rockets, and ballistic missile defense trajectory control. Throttleable LREs can also continuously follow the most economical thrust curve in a given situation, compared to discrete throttling changes over a few select operating points. The effects of variable thrust on the mechanics and dynamics of an LRE as well as difficulties and issues surrounding the throttling process are important aspects of throttling behavior. This review provides a detailed survey of LRE throttling centered around engines from the United States. Several LRE throttling methods are discussed, including high-pressure-drop systems, dual-injector manifolds, gas injection, multiple chambers, pulse modulation, throat throttling, movable injector components, and hydrodynamically dissipative injectors. Concerns and issues surrounding each method are examined, and the advantages and shortcomings compared.
Axial mode shock wave combustion instability in liquid propellant rocket engines
Ablative material degradation in liquid propellant rocket engine environment of nitrogen tetroxide-aerozine
Injection mass flux distributions and resonant combustion effects on local heat transfer in liquid propellant rocket engine
Ablative response of silica phenolic to simulated liquid propellant rocket engine operating conditions
Spray properties of unlike impinging streams of nonreacting fluids for design application to liquid propellant rocket engine injector
Performance, weight, design, flexibility, engine cycles and reliability of liquid propellant rocket engines used in NASA and USAF vehicles
The development of the following Liquid-Propellant Rocket Engines (LPRE) is reviewed: (1) an alcohol-oxygen single-firing LPRE for use in wingless and winged rockets, (2) a similar multifiring LPRE for use in rocket gliders, (3) a combined solid-liquid propellant rocket engine, and (4) an aircraft LPRE operating on nitric acid and kerosene.
This paper discusses scaling of combustion and combustion performance in liquid propellant rocket engine combustion devices. In development of new combustors, comparisons are often made between predicted performance in a new combustor and measured performance in another combustor with different geometric and thermodynamic characteristics. Without careful interpretation of some key features, the comparison can be misinterpreted and erroneous information used in the design of the new device. This paper provides a review of this performance comparison, including a brief review of the initial liquid rocket scaling research conducted during the 1950s and 1960s, a review of the typical performance losses encountered and how they scale, a description of the typical scaling procedures used in development programs today, and finally a review of several historical development programs to see what insight they can bring to the questions at hand.
Double-dead-time model describing chugging to liquid propellant rocket engines having multielement injectors