Download or read book Experimental Investigation of High Frequency Combustion Instability in Cryogenic Oxygen hydrogen Rocket Engines written by Justin S. Hardi and published by . This book was released on 2012 with total page 207 pages. Available in PDF, EPUB and Kindle. Book excerpt: Self-sustaining pressure oscillations in the combustion chamber, or combustion instability, is a commonly encountered and potentially damaging phenomenon in liquid propellant rocket engines (LPREs). In the high-frequency variety of combustion instability, the pressure oscillations in the combustion chamber take on the form and frequency of an acoustic resonance mode of the combustion chamber volume. The most common mode in naturally occurring instability, and also the most destructive, is the first tangential mode, with acoustic gas oscillations oriented transversally to the direction of propellant injection. The instability is driven by the coupling between acoustic oscillations and unsteady energy release from combustion. The mechanisms through which injection and combustion firstly respond to the acoustic field, and secondly feed energy back into the acoustic field have not yet been fully characterised. Shear coaxial-type injectors are common in LPREs. Past experimental and numerical research efforts have investigated the interaction between this type of injector and transverse acoustic fields. Some experimental efforts have successfully forced transverse acoustic modes and studied their influence on shear coaxial injection under LPRE-like conditions. Acoustic forcing of coaxially injected LOx/H2 has previously been conducted only at low pressures and injection performance levels. This work addresses the lack of experimental data available for the interaction of shear coaxial injection of LOx/H2 with acoustics under conditions representative of industrial engines. A new experimental rocket combustor, designated 'BKH', was developed for investigating the response of a reacting spray of coaxially injected LOx/H2 to an acoustic field. For characterising the response, simultaneous high-speed recordings of both backlit shadowgraph and hydroxyl radical (OH*) chemiluminescence imaging have been captured through optical access windows. The operating conditions of BKH extend to conditions more representative of actual LPREs than has previously been achieved with LOx/H2 in studies of flame-acoustic interaction. BKH was run at pressures of 40 or 60 bar, which correspond to subcritical and supercritical thermo-physical regimes for oxygen. Hydrogen injection temperature was ambient, around 290 K, or cryogenic, around 50 K. An array of multiple injectors was used to better represent real engines. A system for modulating the nozzle exhaust flow was used to induce acoustic perturbations inside the combustion chamber. Two types of perturbation were applied to the near-injection region; oscillating acoustic pressure, and oscillating transverse acoustic velocity. BKH was used to investigate how subcritical or supercritical pressure level and ambient or cryogenic hydrogen injection temperature influence the interaction of acoustic pressure or velocity with injection and combustion processes. Shadowgraph imaging reveals up to 70% reduction in the length of the oxygen jet when subjected to acoustic velocity of amplitude approaching that of the hydrogen injection velocity. Furthermore, the mode of jet breakup changes from its natural growth-and-detachment behaviour to a 'transverse stripping' mechanism. OH* imaging reveals a corresponding decrease in the extent of the flame, and increase in emission intensity. When subjected to acoustic pressure, OH* emission from the flame was observed to fluctuate in phase with pressure. Thus, responses to both acoustic pressure and velocity have been observed in BKH, which together may form the basis of a coupling mechanism for driving natural combustion instability in LPREs.
Download or read book High Frequency Combustion Instabilities in the Dvrc Rocket Combustor written by Terracciano Andrea and published by LAP Lambert Academic Publishing. This book was released on 2014-12-11 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt: This experimental work regards the studies of the high frequency combustion instabilities inside the DVRC (Discretely Variable Resonance Combustor), a liquid rocket engine, developed by the Purdue University at M. J. Zucrow Laboratories, on behalf of Nasa Marshall Space Flight Center. The research revealed that, given these specific flow conditions, combustion instability occurs inside the system during hot fire tests. The most important experimental result of the study showed the oxidizer manifold acting as a damper of the pressure oscillations coming from the combustion chamber and how this can represent an advantage in terms of reduced mechanical loads at the interface with the rest of the feed system. The LEE code based on the linearized Euler equations detected both the combustion instability inside the DVRC and confirmed the positive role of the oxidizer manifold. The best agreement with the experimental results has been observed considering heat addition at the plane of propellants injection into the combustion chamber, showing it is reasonable to assume combustion occurs mainly in proximity of that plane, as the previous works about CVRC and CFD results had already shown.
Download or read book Experimental Investigation of High frequency Longitudinal Combustion Instability in Gaseous Propellant Rocket Motors written by Craig Thomas Bowman and published by . This book was released on 1966 with total page 178 pages. Available in PDF, EPUB and Kindle. Book excerpt: The properties of the longitudinal mode of high-frequency combustion instability in a rocket motor burning premixed gaseous propellants were determined experimentally. The experimental observations were compared with the results of a non-linear instability theory based on a chemical kinetic driving mechanism. It was shown that the theory gives the correct waveform for longitudinal instability. In addition the theory gives the correct qualitative dependence of the stability limits on the mean combustion temperature and activation energy. Harmonic mode longitudinal instabilities were observed. The dependence of the stability limits and instability strength on the mean combustion pressure, combustion chamber length, injector and exhaust nozzle was determined experimentally. Based on the general agreement between the experimental observations and theoretical results it is concluded that the appropriate driving mechanism for high-frequency longitudinal gas-phase combustion instability is chemical kinetics. (Author).
Download or read book An Experimental Investigation of High Frequency Combustion Instability in a Fuel air Combustor written by Don E. Rogers and published by . This book was released on 1954 with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effect of Thrust Per Element on Combustion Stability Characteristics of Hydrogen oxygen Rocket Engines written by Reino J. Salmi and published by . This book was released on 1968 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Theoretical and Experimental Investigations of Longitudinal High Frequency Combustion Instability in a Gas Fueled Rocket Motor written by Jacques Bertrand and published by . This book was released on 1962 with total page 75 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Relations of Combustion Dead Time to Engine Variables for a 20 000 pound thrust Gaseous hydrogen written by Daniel I. Drain and published by . This book was released on 1961 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: Experiments were conducted on an uncooled 20,000lb-thrust gaseous-H and LOX rocket engine over a range of chamber pressure from 45 to 300 psia and oxidant-fuel ratio from 2 to 7. Combustion dead times were measured and compared with dead times calculated from frequency data for two assumed combustion models. Measured combustion dead time decreased with increasing chamber pressure at constant oxidant-fuel ratio or LOX injection velocity. This dead time also decreased with oxidant-fuel ratio at constant chamber pressure or O injection velocity. For the engine model where combustion dead time was considered to be the inverse of twice the measured chamberpressure frequency, only a fair agreement with the measured dead time was obtained. When the measured chamber-pressure frequencies were corrected for gas-dynamics effects in terms of the gas residence time, close agreement with the measured dead times was obtained. (Author).
Download or read book Steady state Rocket Combustion of Gaseous Hydrogen and Liquid Oxygen Part I Experimental Investigation written by L. P. Combs and published by . This book was released on 1964 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt: Combustion of gaseous hydrogen and liquid oxygen was studied experimentally under rocket conditions in an uncooled transparent-walled two-dimensional combustion chamber which simulated a 1-inch-wide diametrical section of a conventional cylindrical rocket combustor. Tests were made with three injector types using hydrogen chilled to simulate regenerative rocket engine injection temperatures. Photographic data were obtained which yielded considerable qualitative insight and quantitative information concerning the propellant combustion processes. (Author).
Download or read book Proceedings written by and published by . This book was released on 1970 with total page 1532 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Experimental Investigation in an Altitude Test Facility of Burning of Excess Combustibles in a Rocket Engine Exhaust written by Harry E. Bloomer and published by . This book was released on 1960 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Liquid Rocket Engine Combustion Instability written by Vigor Young and published by AIAA. This book was released on 1995 with total page 606 pages. Available in PDF, EPUB and Kindle. Book excerpt: Annotation Since the invention of the V-2 rocket during World War II, combustion instabilities have been recognized as one of the most difficult problems in the development of liquid propellant rocket engines. This book is the first published in the United States on the subject since NASA's Liquid Rocket Combustion Instability (NASA SP-194) in 1972. In this book, experts cover four major subject areas: engine phenomenology and case studies, fundamental mechanisms of combustion instability, combustion instability analysis, and engine and component testing. Especially noteworthy is the inclusion of technical information from Russia and China--a first.
Download or read book On the Behavior of a Shear Coaxial Jet Spanning Sub to Supercritical Pressures with and Without an Externally Imposed Transverse Acoustic Field written by and published by . This book was released on 2006 with total page 262 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the past, liquid rocket engines (LRE) have experienced high-frequency combustion instability, which impose an acoustic field in the combustion chamber. The acoustic field interacts with the fluid jets issuing from the injectors, thus altering the behavior of the jet compared to that of stable operation of the LRE. It is possible that this interaction could be a substantial feed back mechanism driving the combustion instability. In order to understand the problem of combustion instability, it is necessary to understand the interaction of the jet with the acoustic waves. From past combustion instability studies of the liquid oxygen and hydrogen propellant combination in a shear-coaxial injector configuration, a design guideline of outer-to-inner jet velocity ratio greater than about ten was proposed in order to avoid high-frequency acoustic combustion instability problems. However, no satisfactory physical explanation was provided. To promote this understanding, a cold-flow experimental investigation of a shear-coaxial jet interacting with a high-amplitude non-linear acoustic field was undertaken under chamber pressures extending into the supercritical regime. Liquid nitrogen (LN2) flowed from the inner tube of a coaxial injector while gaseous nitrogen (GN2) issued from its annular region. The injector fluids were directed into a chamber pressurized with gaseous nitrogen. The acoustic excitation was provided by an external driver capable of delivering acoustic field amplitudes up to 165 dB. The resonant modes of the chamber governed the two frequencies studied here, with the first two modes being about 3 and 5.2 kHz. High-speed images of the jet were taken with a Phantom CMOS camera.
Download or read book Experimental Performance of Liquid Hydrogen and Liquid Fluorine in Regeneratively Cooled Rocket Engines written by H. W. Douglass and published by . This book was released on 1959 with total page 58 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book NASA Technical Note written by and published by . This book was released on 1968 with total page 830 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Experimental Investigation of Injection Coupled High Frequency Combustion Instabilities written by Wolfgang Armbruster and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Dynamic Response of Gaseous hydrogen Flow System and Its Application to High frequency Combustion Instability written by Charles E. Feiler and published by . This book was released on 1967 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Liquid Propellant Rocket Combustion Instability written by and published by . This book was released on 1972 with total page 668 pages. Available in PDF, EPUB and Kindle. Book excerpt:
