Aerodynamic losses in low-pressure tailpipe exhaust ducts for rocket-propelled aircraft
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Thibodaux, J G↗
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Some Observations on Exhaust Recirculation from Clustered Rocket Nozzles
A short-duration rocket testing technique which exactly duplicates the combustion flows of multi-engine rocket boosters at high altitudes is described. The application of this technique to the investigation of the reverse flow characteristics of a 4-engine rocket cluster model is discussed. The use of a comparatively new diagnostic tool, the electron beam density probe, in mapping the recirculating flow field of a rocket cluster is described and experimental density results presented. Finally, the use of a reflection plane for the examination of reverse flow phenomena, whereby a plane of symmetry is replaced by a solid surface on which measurements may be made,is evaluated and experimental data presented.
Hendershot, K. C.↗
Studies of exhaust products from solid propellant rocket motors fired in an environmental chamber
Experiments are described in which it was attempted to define the state of HCl when rocket motors using ammonium perchlorate and powdered aluminum filler in the fuel system are fired under various relative humidity conditions. A small, variable load rocket motor was developed so that controlled quantities of exhaust products could be produced in an environmental chamber. A technique is described for distinguishing the difference between HCl existing as a gas or existing as an acid aerosol.
Dawbarn, R.↗
Study on the spectral emissivity of carbon particles produced by a rocket motor Final report
Spectral emissivity of carbon particles in exhaust gases of rocket engines using oxygen and RP-1 PROPELLANTS
SPECTRAL EMISSION↗
Investigation of the Rocket Induced Flow Field in a Rectangular Duct
Rocket-Based Combined Cycle (RBCC) concepts attempt to improve the performance of launch vehicles at all points in the launch trajectory and make highly reusable launch vehicles a reality. The Aerojet Strutjet RBCC concept consists of a variable geometry duct with internal, vertical struts that functions in ducted rocket, ramjet, scramjet, and pure rocket modes. These struts have rocket and turbine exhaust nozzles imbedded within them. The rocket flows create an ejector effect with the ingested air at subsonic flight velocities. In ramjet and scramjet modes, the fuel rich nozzle flows react with the ingested air producing an afterburner effect. Under a NASA Marshall Space Flight Center contract, the UAH Propulsion Research Center (PRC) has designed and built a Strutjet simulation facility. A scale model of a single strut has been built and is undergoing cold-flow testing to investigate the mixing of the rocket and turbine exhausts with the ingested air. A complementary experimental program is also underway to examine the induced flow-field generated by rocket nozzles confined in a rectangular duct. Characterizing the induced flow behavior is critical to understanding and optimizing the performance of future Strutjet-based RBCC propulsion systems. The proposed paper will present results from the rocket induced flow investigation.
Landrum, D. Brian↗
Solid propellant exhausted aluminum oxide and hydrogen chloride - Environmental considerations
Measurements of gaseous hydrogen chloride (HCl) and particulate aluminum oxide (Al2O3) were made during penetrations of five Space Shuttle exhaust clouds and one static ground test firing of a shuttle booster. Instrumented aircraft were used to penetrate exhaust clouds and to measure and/or collect samples of exhaust for subsequent analyses. The focus was on the primary solid rocket motor exhaust products, HCl and Al2O3, from the Space Shuttle's solid boosters. Time-dependent behavior of HCl was determined for the exhaust clouds. Composition, morphology, surface chemistry, and particle size distributions were determined for the exhausted Al2O3. Results determined for the exhaust cloud from the static test firing were complicated by having large amounts of entrained alkaline ground debris (soil) in the lofted cloud. The entrained debris may have contributed to neutralization of in-cloud HCl.
Cofer, W. R., III↗
Exhaust cloud rise and diffusion in the atmosphere
Analytical approach develops physical-mathematical model of rocket engine exhaust cloud rise, growth, and diffusion. Analytic derivations and resultant model apply to hot exhaust cloud study or industrial stack plumes, making work results applicable to air pollution. Model formulations apply to all exhaust cloud types and various atmospheric conditions.
Chandler, M. W.↗
Ground cloud air quality effects
The effects of the ground cloud associated with launching of a large rocket on air quality are discussed. The ground cloud consists of the exhaust emitted by the rocket during the first 15 to 25 seconds following ignition and liftoff, together with a large quantity of entrained air, cooling water, dust and other debris. Immediately after formation, the ground cloud rises in the air due to the buoyant effect of its high thermal energy content. Eventually, at an altitude typically between 0.7 and 3 km, the cloud stabilizes and is carried along by the prevailing wind at that altitude. For the use of heavy lift launch vehicles small quantities of nitrogen oxides, primarily nitric oxide and nitrogen dioxide, are expected to be produced from a molecular nitrogen impurity in the fuel or liquid oxygen, or from entrainment and heating of ambient air in the hot rocket exhaust. In addition, possible impurities such as sulfur in the fuel would give rise to a corresponding amount of oxidation products such as sulfur dioxide.
Brubaker, K. L.↗
Prediction of Launch Vehicle Ignition Overpressure and Liftoff Acoustics
The LAIOP (Launch Vehicle Ignition Overpressure and Liftoff Acoustic Environments) program predicts the external pressure environment generated during liftoff for a large variety of rocket types. These environments include ignition overpressure, produced by the rapid acceleration of exhaust gases during rocket-engine start transient, and launch acoustics, produced by turbulence in the rocket plume. The ignition overpressure predictions are time-based, and the launch acoustic predictions are frequency-based. Additionally, the software can predict ignition overpressure mitigation, using water-spray injection into the rocket exhaust stream, for a limited number of configurations. The framework developed for these predictions is extensive, though some options require additional relevant data and development time. Once these options are enabled, the already extensively capable code will be further enhanced. The rockets, or launch vehicles, can either be elliptically or cylindrically shaped, and up to eight strap-on structures (boosters or tanks) are allowed. Up to four engines are allowed for the core launch vehicle, which can be of two different types. Also, two different sizes of strap-on structures can be used, and two different types of booster engines are allowed. Both tabular and graphical presentations of the predicted environments at the selected locations can be reviewed by the user. The output includes summaries of rocket-engine operation, ignition overpressure time histories, and one-third octave sound pressure spectra of the predicted launch acoustics. Also, documentation is available to the user to help him or her understand the various aspects of the graphical user interface and the required input parameters.
Casiano, Matthew↗
Environment effects from SRB exhaust effluents: Technique development and preliminary assessment
Techniques to determine the environmental effects from the space shuttle SRB (Solid Rocket Booster) exhaust effluents are used to perform a preliminary climatological assessment. The exhaust effluent chemistry study was performed and the exhaust effluent species were determined. A reasonable exhaust particle size distribution is constructed for use in nozzle analyses and for the deposition model. The preliminary assessment is used to identify problems that are associated with the full-scale assessment; therefore, these preliminary air quality results are used with caution in drawing conclusion regarding the environmental effects of the space shuttle exhaust effluents.
Goldford, A. I.↗
Mixing of Supersonic Streams
The Strutjet approach to Rocket Based Combined Cycle (RBCC) propulsion depends upon fuel-rich flows from the rocket nozzles and turbine exhaust products mixing with the ambient air for successful operation in the ramjet and scramjet modes. A model of the Strutjet device has been built and is undergoing test to investigate the mixing of the streams as a function of distance from the Strutjet exit plane. The modeling basis was centered on using convective Mach Number as the similarity parameter to establish correlation between subscale, cold flow tests and full scale, hot firing modes. This parameter has been used successfully to correlate supersonic shear layer growth rates. The experiment design includes hot (600 R) air as the rocket exhaust simulant and hot (760 R) carbon dioxide as the turbine exhaust gas simulant. The combination of gases and their elevated temperatures was required to achieve a convective Mach Number which matched the fall scale item design conditions. The carbon dioxide is seeded with Acetone to permit tracing of the mixing processes through Laser Induced Fluorescence (LIF) techniques. The experiment and its design will be discussed in detail. Both the rocket and turbine exhaust duct nozzles are of unique (square and rectangular) shape and the turbine exhaust e)dt intersects the rocket nozzle wall upstream of the exit. Cold flow testing with the individual nozzles has been conducted to ascertain their behavior in comparison to conventional flow theory. These data are presented.
Hawk, Clark W.↗
Range safety signal propagation through the SRM exhaust plume of the space shuttle
Theoretical predictions of plume interference for the space shuttle range safety system by solid rocket booster exhaust plumes are reported. The signal propagation was calculated using a split operator technique based upon the Fresnel-Kirchoff integral, using fast Fourier transforms to evaluate the convolution and treating the plume as a series of absorbing and phase-changing screens. Talanov's lens transformation was applied to reduce aliasing problems caused by ray divergence.
Boynton, F. P.↗
Wavelength-Agile Optical Sensor for Exhaust Plume and Cryogenic Fluid Interrogation
Two optical sensors developed in UW-Madison labs were evaluated for their potential to characterize rocket engine exhaust plumes and liquid oxygen (LOX) fluid properties. The plume sensor is based on wavelength-agile absorption spectroscopy A device called a chirped white pulse emitter (CWPE) is used to generate the wavelength agile light, scanning, for example, 1340 - 1560 nm every microsecond. Properties of the gases in the rocket plume (for example temperature and water mole fraction) can be monitored using these wavelength scans. We have performed preliminary tests in static gas cells, a laboratory GOX/GH2 thrust chamber, and a solid-fuel hybrid thrust chamber, and these initial tests demonstrate the potential of the CWPE for monitoring rocket plumes. The LOX sensor uses an alternative to wavelength agile sensing: two independent, fixed-wavelength lasers are combined into a single fiber. One laser is absorbed by LOX and the other not: by monitoring the differential transmission the LOX concentration in cryogenic feed lines can be inferred. The sensor was successful in interrogating static LOX pools in laboratory tests. Even in ice- and bubble-laden cryogenic fluids, LOX concentrations were measured to better than 1% with a 3 microsec time constant.
Sanders, Scott T.↗
HEAT TRANSFER TO A SPHERE WITH A RETROROCKET EXHAUSTING INTO A FREE STREAM, MACH 2.0 AND 0.8
Heat transfer to a sphere with a retrorocket exhausting into a freestream
FREE STREAM↗
Design and Evaluation of a Turbojet Exhaust Simulator, Utilizing a Solid-Propellant Rocket Motor, for use in Free-Flight Aerodynamic Research Models
A method has been developed for modifying a rocket motor so that its exhaust characteristics simulate those of a turbojet engine. The analysis necessary to the design is presented along with tests from which the designs are evaluated. Simulation was found to be best if the exhaust characteristics to be duplicated were those of a turbojet engine at high altitudes and with the afterburner operative.
deMoraes, Carlos A.↗
The Saturn S-IV stage base thermal environment flight and scale model data comparison.
Base heating in Saturn S-IV stage from exhaust reversal, comparing flight and scale model data
BASE HEATING↗
LAUNCH DEFLECTOR DESIGN CRITERIA AND THEIR APPLICATION TO THE SATURN C-1 DEFLECTOR
Launch deflector design criteria and saturn c-1 deflector for exhaust jet energy distribution
SATURN I LAUNCH VEHICLE↗
Study of high altitude plume impingement
Computer program has been developed as analytical tool to predict severity of effects of exhaust of rocket engines on adjacent spacecraft surfaces. Program computes forces, moments, pressures, and heating rates on surfaces immersed in or subjected to exhaust plume environments. Predictions will be useful in design of systems where such problems are anticipated.
Wojciechowski, C. J.↗