WorldWideScience

Sample records for pulse rocket performance

  1. Pulse Detonation Rocket MHD Power Experiment

    Science.gov (United States)

    Litchford, Ron J.; Cook, Stephen (Technical Monitor)

    2002-01-01

    A pulse detonation research engine (MSFC (Marshall Space Flight Center) Model PDRE (Pulse Detonation Rocket Engine) G-2) has been developed for the purpose of examining integrated propulsion and magnetohydrodynamic power generation applications. The engine is based on a rectangular cross-section tube coupled to a converging-diverging nozzle, which is in turn attached to a segmented Faraday channel. As part of the shakedown testing activity, the pressure wave was interrogated along the length of the engine while running on hydrogen/oxygen propellants. Rapid transition to detonation wave propagation was insured through the use of a short Schelkin spiral near the head of the engine. The measured detonation wave velocities were in excess of 2500 m/s in agreement with the theoretical C-J velocity. The engine was first tested in a straight tube configuration without a nozzle, and the time resolved thrust was measured simultaneously with the head-end pressure. Similar measurements were made with the converging-diverging nozzle attached. The time correlation of the thrust and head-end pressure data was found to be excellent. The major purpose of the converging-diverging nozzle was to configure the engine for driving an MHD generator for the direct production of electrical power. Additional tests were therefore necessary in which seed (cesium-hydroxide dissolved in methanol) was directly injected into the engine as a spray. The exhaust plume was then interrogated with a microwave interferometer in an attempt to characterize the plasma conditions, and emission spectroscopy measurements were also acquired. Data reduction efforts indicate that the plasma exhaust is very highly ionized, although there is some uncertainty at this time as to the relative abundance of negative OH ions. The emission spectroscopy data provided some indication of the species in the exhaust as well as a measurement of temperature. A 24-electrode-pair segmented Faraday channel and 0.6 Tesla permanent

  2. Pulse Detonation Rocket MHD Power Experiment

    Science.gov (United States)

    Litchford, Ron J.; Cook, Stephen (Technical Monitor)

    2002-01-01

    A pulse detonation research engine (MSFC (Marshall Space Flight Center) Model PDRE (Pulse Detonation Rocket Engine) G-2) has been developed for the purpose of examining integrated propulsion and magnetohydrodynamic power generation applications. The engine is based on a rectangular cross-section tube coupled to a converging-diverging nozzle, which is in turn attached to a segmented Faraday channel. As part of the shakedown testing activity, the pressure wave was interrogated along the length of the engine while running on hydrogen/oxygen propellants. Rapid transition to detonation wave propagation was insured through the use of a short Schelkin spiral near the head of the engine. The measured detonation wave velocities were in excess of 2500 m/s in agreement with the theoretical C-J velocity. The engine was first tested in a straight tube configuration without a nozzle, and the time resolved thrust was measured simultaneously with the head-end pressure. Similar measurements were made with the converging-diverging nozzle attached. The time correlation of the thrust and head-end pressure data was found to be excellent. The major purpose of the converging-diverging nozzle was to configure the engine for driving an MHD generator for the direct production of electrical power. Additional tests were therefore necessary in which seed (cesium-hydroxide dissolved in methanol) was directly injected into the engine as a spray. The exhaust plume was then interrogated with a microwave interferometer in an attempt to characterize the plasma conditions, and emission spectroscopy measurements were also acquired. Data reduction efforts indicate that the plasma exhaust is very highly ionized, although there is some uncertainty at this time as to the relative abundance of negative OH ions. The emission spectroscopy data provided some indication of the species in the exhaust as well as a measurement of temperature. A 24-electrode-pair segmented Faraday channel and 0.6 Tesla permanent

  3. Robust lateral pulse jet control of an atmospheric rocket

    Science.gov (United States)

    Burchett, Bradley Thomas

    Uncontrolled direct fire rockets exhibit high impact point dispersion, even at relatively short range, and as such have been employed as area weapons on the battlefield. In order to reduce the dispersion of a direct fire rocket, feedback control is employed to fire short-duration solid rocket pulses mounted near the nose of the projectile and acting perpendicular to the projectile axis of symmetry. The feedback law is developed by first determining a piece wise linear model of the projectile swerving motion, subsequently using this linear model to predict the projectile impact point both with and without control, and using the results to command pulses at appropriate times to drive the impact point closer to the specified target. Candidate optimal control laws are formed using rules based on decision grids, and a global control strategy search algorithm. The global search control law proves to be prohibitively computationally expensive for on-line implementation. The performance of the baseline control law is found to be comparable to the rule based and global search optimal control laws. The control gains of the baseline control law are optimized in the presence of parametric plant uncertainty using a Monte Carlo simulation. Performance of the system in the presence of parametric plant uncertainty using the optimized gains is deemed comparable to performance of the baseline controller with no plant uncertainty. The level of uncertainty of several plant parameters is varied in order to compare robustness of the controller when optimized with uncertainty viz. without uncertainty.

  4. Axisymmetric Numerical Modeling of Pulse Detonation Rocket Engines

    Science.gov (United States)

    Morris, Christopher I.

    2005-01-01

    Pulse detonation rocket engines (PDREs) have generated research interest in recent years as a chemical propulsion system potentially offering improved performance and reduced complexity compared to conventional rocket engines. The detonative mode of combustion employed by these devices offers a thermodynamic advantage over the constant-pressure deflagrative combustion mode used in conventional rocket engines and gas turbines. However, while this theoretical advantage has spurred considerable interest in building PDRE devices, the unsteady blowdown process intrinsic to the PDRE has made realistic estimates of the actual propulsive performance problematic. The recent review article by Kailasanath highlights some of the progress that has been made in comparing the available experimental measurements with analytical and numerical models. In recent work by the author, a quasi-one-dimensional, finite rate chemistry CFD model was utilized to study the gasdynamics and performance characteristics of PDREs over a range of blowdown pressure ratios from 1-1000. Models of this type are computationally inexpensive, and enable first-order parametric studies of the effect of several nozzle and extension geometries on PDRE performance over a wide range of conditions. However, the quasi-one-dimensional approach is limited in that it cannot properly capture the multidimensional blast wave and flow expansion downstream of the PDRE, nor can it resolve nozzle flow separation if present. Moreover, the previous work was limited to single-pulse calculations. In this paper, an axisymmetric finite rate chemistry model is described and utilized to study these issues in greater detail. Example Mach number contour plots showing the multidimensional blast wave and nozzle exhaust plume are shown. The performance results are compared with the quasi-one-dimensional results from the previous paper. Both Euler and Navier-Stokes solutions are calculated in order to determine the effect of viscous

  5. Thrust stand for low-thrust liquid pulsed rocket engines.

    Science.gov (United States)

    Xing, Qin; Zhang, Jun; Qian, Min; Jia, Zhen-yuan; Sun, Bao-yuan

    2010-09-01

    A thrust stand is developed for measuring the pulsed thrust generated by low-thrust liquid pulsed rocket engines. It mainly consists of a thrust dynamometer, a base frame, a connecting frame, and a data acquisition and processing system. The thrust dynamometer assembled with shear mode piezoelectric quartz sensors is developed as the core component of the thrust stand. It adopts integral shell structure. The sensors are inserted into unique double-elastic-half-ring grooves with an interference fit. The thrust is transferred to the sensors by means of static friction forces of fitting surfaces. The sensors could produce an amount of charges which are proportional to the thrust to be measured. The thrust stand is calibrated both statically and dynamically. The in situ static calibration is performed using a standard force sensor. The dynamic calibration is carried out using pendulum-typed steel ball impact technique. Typical thrust pulse is simulated by a trapezoidal impulse force. The results show that the thrust stand has a sensitivity of 25.832 mV/N, a linearity error of 0.24% FSO, and a repeatability error of 0.23% FSO. The first natural frequency of the thrust stand is 1245 Hz. The thrust stand can accurately measure thrust waveform of each firing, which is used for fine control of on-orbit vehicles in the thrust range of 5-20 N with pulse frequency of 50 Hz.

  6. Magnetohydrodynamic Augmentation of Pulse Detonation Rocket Engines (Preprint)

    Science.gov (United States)

    2010-09-28

    Detonation Rocket-Induced MHD Ejector (PDRIME) concept, energy could be extracted from the high speed portion of the system, e.g., through an MHD...but with some challenges associated with achieving these gains, suggesting further analysis and optimization are required. 15. SUBJECT TERMS 16...mentation, such as in the Pulse Detonation Rocket-Induced MHD Ejector (PDRIME) concept, energy could be extracted from the high speed por- tion of the system

  7. Standardization of Rocket Engine Pulse Time Parameters

    Science.gov (United States)

    Larin, Max E.; Lumpkin, Forrest E.; Rauer, Scott J.

    2001-01-01

    Plumes of bipropellant thrusters are a source of contamination. Small bipropellant thrusters are often used for spacecraft attitude control and orbit correction. Such thrusters typically operate in a pulse mode, at various pulse lengths. Quantifying their contamination effects onto spacecraft external surfaces is especially important for long-term complex-geometry vehicles, e.g. International Space Station. Plume contamination tests indicated the presence of liquid phase contaminant in the form of droplets. Their origin is attributed to incomplete combustion. Most of liquid-phase contaminant is generated during the startup and shutdown (unsteady) periods of thruster pulse. These periods are relatively short (typically 10-50 ms), and the amount of contaminant is determined by the thruster design (propellant valve response, combustion chamber size, thruster mass flow rate, film cooling percentage, dribble volume, etc.) and combustion process organization. Steady-state period of pulse is characterized by much lower contamination rates, but may be lengthy enough to significantly conh'ibute to the overall contamination effect. Because there was no standard methodology for thruster pulse time division, plume contamination tests were conducted at various pulse durations, and their results do not allow quantifying contaminant amounts from each portion of the pulse. At present, the ISS plume contamination model uses an assumption that all thrusters operate in a pulse mode with the pulse length being 100 ms. This assumption may lead to a large difference between the actual amounts of contaminant produced by the thruster and the model predictions. This paper suggests a way to standardize thruster startup and shutdown period definitions, and shows the usefulness of this approach to better quantify thruster plume contamination. Use of the suggested thruster pulse time-division technique will ensure methodological consistency of future thruster plume contamination test programs

  8. Pulse-on-bias rocket propulsion concept

    Science.gov (United States)

    Vulpetti, Giovanni

    1982-03-01

    An approach to maximise the terminal velocity of a powered spacecraft is investigated through a variable specific impulse programme from two specific-impulse-constant engines. One propulsion system works in a continuous mode. The other one does in a pulsed mode. The variable jet speed is obtained by allowing the time between two consecutive pulses to vary. Modeling the "bias" and pulsed engines together with S/C significant systems a nonlinear programming problem is stated. Propellant and P/L, effective power and propulsion time are fixed. Specialising the problem to a NEP S/C for distant targets in the solar system a comparison is made with same flights for which the S/C uses one propulsion system. There exist ranges of initial mass and propellant fraction where the final ship velocity augments considerably in the pulse-on-bias policy, especially at lower power levels. In such environments, a meaningful example is a gain of three targets—from Saturn to Pluto—for a 5-ton 150-kWe 75-day 32%-fuel acceleration flight.

  9. Damage assessment of long-range rocket system by electromagnetic pulse weapon

    Science.gov (United States)

    Cao, Lingyu; Liu, Guoqing; Li, Jinming

    2017-08-01

    This paper analyzes the damage mechanism and characteristics of electromagnetic pulse weapon, establishes the index system of survivability of long-range rocket launcher system, and uses AHP method to establish the combat effectiveness model of long-range rocket missile system. According to the damage mechanism and characteristics of electromagnetic pulse weapon, the damage effect of the remote rocket system is established by using the exponential method to realize the damage efficiency of the remote rocket system.

  10. Development of high performance hybrid rocket fuels

    Science.gov (United States)

    Zaseck, Christopher R.

    . In order to examine paraffin/additive combustion in a motor environment, I conducted experiments on well characterized aluminum based additives. In particular, I investigate the influence of aluminum, unpassivated aluminum, milled aluminum/polytetrafluoroethylene (PTFE), and aluminum hydride on the performance of paraffin fuels for hybrid rocket propulsion. I use an optically accessible combustor to examine the performance of the fuel mixtures in terms of characteristic velocity efficiency and regression rate. Each combustor test consumes a 12.7 cm long, 1.9 cm diameter fuel strand under 160 kg/m 2s of oxygen at up to 1.4 MPa. The experimental results indicate that the addition of 5 wt.% 30 mum or 80 nm aluminum to paraffin increases the regression rate by approximately 15% compared to neat paraffin grains. At higher aluminum concentrations and nano-scale particles sizes, the increased melt layer viscosity causes slower regression. Alane and Al/PTFE at 12.5 wt.% increase the regression of paraffin by 21% and 32% respectively. Finally, an aging study indicates that paraffin can protect air and moisture sensitive particles from oxidation. The opposed burner and aluminum/paraffin hybrid rocket experiments show that additives can alter bulk fuel properties, such as viscosity, that regulate entrainment. The general effect of melt layer properties on the entrainment and regression rate of paraffin is not well understood. Improved understanding of how solid additives affect the properties and regression of paraffin is essential to maximize performance. In this document I investigate the effect of melt layer properties on paraffin regression using inert additives. Tests are performed in the optical cylindrical combustor at ˜1 MPa under a gaseous oxygen mass flux of ˜160 kg/m2s. The experiments indicate that the regression rate is proportional to mu0.08rho 0.38kappa0.82. In addition, I explore how to predict fuel viscosity, thermal conductivity, and density prior to testing

  11. Rocket

    Directory of Open Access Journals (Sweden)

    K. Karmarkar

    1952-09-01

    Full Text Available The rockets of World War II represented, not the invention of a new weapon, but the modernization of a very old one. As early as 1232 A.D, the Chinese launched rockets against the Mongols. About a hundred years later the knowledge of ledge of rockets was quite widespread and they were used to set fire to buildings and to terrorize the enemy. But as cannon developed, rockets declined in warfare. However rockets were used occasionally as weapons till about 1530 A.D. About this time improvements in artillery-rifled gun barrel and mechanism to absorb recoil-established a standard of efficiency with which rockets could not compare until World War II brought pew conditions

  12. Performance Charts for Multistage Rocket Boosters

    Science.gov (United States)

    MacKay, John S.; Weber, Richard J.

    1961-01-01

    Charts relating the stage propellant fractions are given for two-and three-stage rockets launching payloads into nominal low-altitude circular orbits about the earth. A simple method is described for extending these data to higher orbit or escape missions. Various combinations of stages using RP - liquid-oxygen and hydrogen - liquid-oxygen propellants are considered. However, the results can be generalized with little error to any other propellant combination.Charts relating the stage propellant fractions are given for two-and three-stage rockets launching payloads into nominal low-altitude circular orbits about the earth. A simple method is described for extending these data to higher orbit or escape missions. Various combinations of stages using RP - liquid-oxygen and hydrogen - liquid-oxygen propellants are considered. However, the results can be generalized with little error to any other propellant combination.

  13. Analytical study of nozzle performance for nuclear thermal rockets

    Science.gov (United States)

    Davidian, Kenneth O.; Kacynski, Kenneth J.

    1991-01-01

    A parametric study has been conducted by the NASA-Lewis Rocket Engine Design Expert System for the convergent-divergent nozzle of the Nuclear Thermal Rocket system, which uses a nuclear reactor to heat hydrogen to high temperature and then expands it through the nozzle. It is established by the study that finite-rate chemical reactions lower performance levels from theoretical levels. Major parametric roles are played by chamber temperature and chamber pressure. A maximum performance of 930 sec is projected at 2700 K, and of 1030 at 3100 K.

  14. Nuclear rockets: High-performance propulsion for Mars

    Science.gov (United States)

    Watson, C. W.

    1994-05-01

    A new impetus to manned Mars exploration was introduced by President Bush in his Space Exploration Initiative. This has led, in turn, to a renewed interest in high-thrust nuclear thermal rocket propulsion (NTP). The purpose of this report is to give a brief tutorial introduction to NTP and provide a basic understanding of some of the technical issues in the realization of an operational NTP engine. Fundamental physical principles are outlined from which a variety of qualitative advantages of NTP over chemical propulsion systems derive, and quantitative performance comparisons are presented for illustrative Mars missions. Key technologies are described for a representative solid-core heat-exchanger class of engine, based on the extensive development work in the Rover and NERVA nuclear rocket programs (1955 to 1973). The most driving technology, fuel development, is discussed in some detail for these systems. Essential highlights are presented for the 19 full-scale reactor and engine tests performed in these programs. On the basis of these tests, the practicality of graphite-based nuclear rocket engines was established. Finally, several higher-performance advanced concepts are discussed. These have received considerable attention, but have not, as yet, developed enough credibility to receive large-scale development.

  15. Feasibility and Performance of the Microwave Thermal Rocket Launcher

    Science.gov (United States)

    Parkin, Kevin L. G.; Culick, Fred E. C.

    2004-03-01

    Beamed-energy launch concepts employing a microwave thermal thruster are feasible in principle, and microwave sources of sufficient power to launch tons into LEO already exist. Microwave thermal thrusters operate on an analogous principle to nuclear thermal thrusters, which have experimentally demonstrated specific impulses exceeding 850 seconds. Assuming such performance, simple application of the rocket equation suggests that payload fractions of 10% are possible for a single stage to orbit (SSTO) microwave thermal rocket. We present an SSTO concept employing a scaled X-33 aeroshell. The flat aeroshell underside is covered by a thin-layer microwave absorbent heat-exchanger that forms part of the thruster. During ascent, the heat-exchanger faces the microwave beam. A simple ascent trajectory analysis incorporating X-33 aerodynamic data predicts a 10% payload fraction for a 1 ton craft of this type. In contrast, the Saturn V had 3 non-reusable stages and achieved a payload fraction of 4%.

  16. Experimental study of a valveless pulse detonation rocket engine using nontoxic hypergolic propellants

    Science.gov (United States)

    Kan, Brandon K.

    A pulsed detonation rocket engine concept was explored through the use of hypergolic propellants in a fuel-centered pintle injector combustor. The combustor design yielded a simple open ended chamber with a pintle type injection element and pressure instrumentation. High-frequency pressure measurements from the first test series showed the presence of large pressure oscillations in excess of 2000 psia at frequencies between 400-600 hz during operation. High-speed video confirmed the high-frequency pulsed behavior and large amounts of after burning. Damaged hardware and instrumentation failure limited the amount of data gathered in the first test series, but the experiments met original test objectives of producing large over-pressures in an open chamber. A second test series proceeded by replacing hardware and instrumentation, and new data showed that pulsed events produced under expanded exhaust prior to pulsing, peak pressures around 8000 psi, and operating frequencies between 400-800 hz. Later hot-fires produced no pulsed behavior despite undamaged hardware. The research succeeded in producing pulsed combustion behavior using hypergolic fuels in a pintle injector setup and provided insights into design concepts that would assist future injector designs and experimental test setups.

  17. Priming and physiological performance of rocket salad seeds

    Directory of Open Access Journals (Sweden)

    Jarbas Alves

    2012-03-01

    Full Text Available Rocket salad is a leafy vegetable that has become a popular food in various regions of Brazil. Its multiplication is only possible with seeds and, therefore, high quality propagation material is necessary for establishing a good crop. Studies show that seed conditioning promotes physiological improvements in the speed and uniformity of seedling establishment in the field. The present work was carried out in order to verify the effect of priming on the performance of rocket salad seeds. Five seed lots of rocket salad, cultivar Cultivada, were primed for 24 hours, using the potentials of 0.0, -0.1, -0.2, -0.3MPa, in a polyethylene glycol (Carbonax 6000 solution. A completely randomized design with 20 treatments (5 seed lots × 4 potentials was used, with four replications. Means were compared by Tukey’s test and regression analyses were conducted for the osmotic potential. The data showed that priming improved germination and the percentage of strong plants in relation to vigor.

  18. Analytical study of nozzle performance for nuclear thermal rockets

    Science.gov (United States)

    Davidian, Kenneth O.; Kacynski, Kenneth J.

    1991-01-01

    Nuclear propulsion has been identified as one of the key technologies needed for human exploration of the Moon and Mars. The Nuclear Thermal Rocket (NTR) uses a nuclear reactor to heat hydrogen to a high temperature followed by expansion through a conventional convergent-divergent nozzle. A parametric study of NTR nozzles was performed using the Rocket Engine Design Expert System (REDES) at the NASA Lewis Research Center. The REDES used the JANNAF standard rigorous methodology to determine nozzle performance over a range of chamber temperatures, chamber pressures, thrust levels, and different nozzle configurations. A design condition was set by fixing the propulsion system exit radius at five meters and throat radius was varied to achieve a target thrust level. An adiabatic wall was assumed for the nozzle, and its length was assumed to be 80 percent of a 15 degree cone. The results conclude that although the performance of the NTR, based on infinite reaction rates, looks promising at low chamber pressures, finite rate chemical reactions will cause the actual performance to be considerably lower. Parameters which have a major influence on the delivered specific impulse value include the chamber temperature and the chamber pressures in the high thrust domain. Other parameters, such as 2-D and boundary layer effects, kinetic rates, and number of nozzles, affect the deliverable performance of an NTR nozzle to a lesser degree. For a single nozzle, maximum performance of 930 seconds and 1030 seconds occur at chamber temperatures of 2700 and 3100 K, respectively.

  19. Numerical Simulation of a Dual Pulse Solid Rocket Motor Flow Field

    Directory of Open Access Journals (Sweden)

    Afroz Javed

    2012-11-01

    Full Text Available Numerical simulations are carried out for the internal flow field of a dual pulse solid rocket motor port to understand the flow behaviour. Three dimensional Reynolds Averaged Navier Stokes equations are solved alongwith shear stress transport turbulence model using commercial code. The combustion gas is assumed as a mixture of alumina and gases and single phase flow calculations are done with the thermo chemical properties provided for the mixture. The simulation captures all the essential features of the flow field. The flow accelerates through the pulse separation device (PSD port and high temperature and high velocity gas is seen to impinge the motor wall near the PSD port. The overall total pressure drop through motor port and through PSD is found to be moderate.Defence Science Journal, 2012, 62(6, pp.369-374, DOI:http://dx.doi.org/10.14429/dsj.62.1418

  20. High Energy Density Additives for Hybrid Fuel Rockets to Improve Performance and Enhance Safety

    Science.gov (United States)

    Jaffe, Richard L.

    2014-01-01

    We propose a conceptual study of prototype strained hydrocarbon molecules as high energy density additives for hybrid rocket fuels to boost the performance of these rockets without compromising safety and reliability. Use of these additives could extend the range of applications for which hybrid rockets become an attractive alternative to conventional solid or liquid fuel rockets. The objectives of the study were to confirm and quantify the high enthalpy of these strained molecules and to assess improvement in rocket performance that would be expected if these additives were blended with conventional fuels. We confirmed the chemical properties (including enthalpy) of these additives. However, the predicted improvement in rocket performance was too small to make this a useful strategy for boosting hybrid rocket performance.

  1. Performance of an Axisymmetric Rocket Based Combined Cycle Engine During Rocket Only Operation Using Linear Regression Analysis

    Science.gov (United States)

    Smith, Timothy D.; Steffen, Christopher J., Jr.; Yungster, Shaye; Keller, Dennis J.

    1998-01-01

    The all rocket mode of operation is shown to be a critical factor in the overall performance of a rocket based combined cycle (RBCC) vehicle. An axisymmetric RBCC engine was used to determine specific impulse efficiency values based upon both full flow and gas generator configurations. Design of experiments methodology was used to construct a test matrix and multiple linear regression analysis was used to build parametric models. The main parameters investigated in this study were: rocket chamber pressure, rocket exit area ratio, injected secondary flow, mixer-ejector inlet area, mixer-ejector area ratio, and mixer-ejector length-to-inlet diameter ratio. A perfect gas computational fluid dynamics analysis, using both the Spalart-Allmaras and k-omega turbulence models, was performed with the NPARC code to obtain values of vacuum specific impulse. Results from the multiple linear regression analysis showed that for both the full flow and gas generator configurations increasing mixer-ejector area ratio and rocket area ratio increase performance, while increasing mixer-ejector inlet area ratio and mixer-ejector length-to-diameter ratio decrease performance. Increasing injected secondary flow increased performance for the gas generator analysis, but was not statistically significant for the full flow analysis. Chamber pressure was found to be not statistically significant.

  2. Evaluation of the GLD360 performance characteristics using rocket-and-wire triggered lightning data

    Science.gov (United States)

    Mallick, S.; Rakov, V. A.; Ngin, T.; Gamerota, W. R.; Pilkey, J. T.; Hill, J. D.; Uman, M. A.; Jordan, D. M.; Nag, A.; Said, R. K.

    2014-05-01

    We estimated the performance characteristics of the Global Lightning Dataset (GLD360) using rocket-and-wire triggered lightning data acquired at Camp Blanding, Florida, in 2011-2013. The data set consisted of 201 return strokes and 84 kiloampere-scale (≥1 kA) superimposed pulses (initial continuous current pulses and M components) in 43 flashes. All the events transported negative charge to ground. The GLD360 detected 75 strokes and 4 superimposed pulses in 29 flashes. The resultant detection efficiencies were 67% for flashes, 37% for strokes, and 4.8% for superimposed pulses. Out of 75 detected strokes, one (1.3%) was reported with incorrect polarity. The median location error was 2.0 km, and the median absolute current estimation error was 27%. This is the first comprehensive evaluation of GLD360 performance characteristics relative to absolute ground truth, with all previous evaluations being at least in part relative to other locating systems. The results presented in this work may be applicable to regions in and around Florida.

  3. Operation of a Rotary-valved Pulse Detonation Rocket Engine Utilizing Liquid-kerosene and Oxygen

    Institute of Scientific and Technical Information of China (English)

    WANG Ke; FAN Wei; YAN Yu; ZHU Xudong; YAN Chuanjun

    2011-01-01

    The pulse detonation rocket engine (PDRE) requires periodic supply of oxidizer,fuel and purge gas.A rotary-valve assembly is fabricated to control the periodic supply in this research.Oxygen and liquid aviation kerosene are used as oxidizer and fuel respectively.An ordinary automobile spark plug,with ignition energy as low as 50 mJ,is used to initiate combustion.Steady operation of the PDRE is achieved with operating frequency ranging from 1 Hz to 10 Hz.Experimentally measured pressure is lower than theoretical value by 13% at 1 Hz and 37% at 10 Hz,and there also exists a velocity deficit at different operating frequencies.Both of these two phenomena are believed mainly due to droplet size which depends on atomization and vaporization of liquid fuel.

  4. Parametric study of solar thermal rocket nozzle performance

    Science.gov (United States)

    Pearson, J. Boise; Landrum, D. Brian; Hawk, Clark W.

    1995-01-01

    This paper details a numerical investigation of performance losses in low-thrust solar thermal rocket nozzles. The effects of nozzle geometry on three types of losses were studied; finite rate dissociation-recombination kinetic losses, two dimensional axisymmetric divergence losses, and compressible viscous boundary layer losses. Short nozzle lengths and supersonic flow produce short residence times in the nozzle and a nearly frozen flow, resulting in large kinetic losses. Variations in geometry have a minimal effect on kinetic losses. Divergence losses are relatively small, and careful shaping of the nozzle can nearly eliminate them. The boundary layer in these small nozzles can grow to a major fraction of nozzle radius, and cause large losses. These losses are attributed to viscous drag on the nozzle walls and flow blockage by the boundary layer, especially in the throat region. Careful shaping of the nozzle can produce a significant reduction in viscous losses.

  5. VSB-30 sounding rocket: history of flight performance

    Directory of Open Access Journals (Sweden)

    Wolfgang Jung

    2011-09-01

    Full Text Available The VSB-30 vehicle is a two-stage, unguided, rail launched sounding rocket, consisting of two solid propellant motors, payload, with recovery and service system. By the end of 2010, ten vehicles had already been launched, three from Brazil (Alcântara and seven from Sweden (Esrange. The objective of this paper is to give an overview of the main characteristics of the first ten flights of the VSB-30, with emphasis on performance and trajectory data. The circular 3σ dispersion area for payload impact point has around 50 km of radius. In most launchings of such vehicle, the impact of the payload fell within 2 sigma. This provides the possibility for further studies to decrease the area of dispersion from the impact point.

  6. Performance Increase Verification for a Bipropellant Rocket Engine

    Science.gov (United States)

    Alexander, Leslie; Chapman, Jack; Wilson, Reed; Krismer, David; Lu, Frank; Wilson, Kim; Miller, Scott; England, Chris

    2008-01-01

    Component performance assessment testing for a, pressure-fed earth storable bipropellant rocket engine was successfully completed at Aerojet's Redmond test facility. The primary goal of the this development project is to increase the specific impulse of an apogee class bi-propellant engine to greater than 330 seconds with nitrogen tetroxide and monomethylhydrazine propellants and greater than 335 seconds with nitrogen tetroxide and hydrazine. The secondary goal of the project is to take greater advantage of the high temperature capabilities of iridium/rhenium chambers. In order to achieve these goals, the propellant feed pressures were increased to 400 psia, nominal, which in turn increased the chamber pressure and temperature, allowing for higher c*. The tests article used a 24-on-24 unlike doublet injector design coupled with a copper heat sink chamber to simulate a flight configuration combustion chamber. The injector is designed to produce a nominal 200 lbf of thrust with a specific impulse of 335 seconds (using hydrazine fuel). Effect of Chamber length on engine C* performance was evaluated with the use of modular, bolt-together test hardware and removable chamber inserts. Multiple short duration firings were performed to characterize injector performance across a range of thrust levels, 180 to 220 lbf, and mixture ratios, from 1.1 to 1.3. During firing, ignition transient, chamber pressure, and various temperatures were measured in order to evaluate the performance of the engine and characterize the thermal conditions. The tests successfully demonstrated the stable operation and performance potential of a full scale engine with a measured c* of XXXX ft/sec (XXXX m/s) under nominal operational conditions.

  7. Hydrogen recombination kinetics and nuclear thermal rocket performance prediction

    Science.gov (United States)

    Wetzel, Kyle K.; Solomon, Wayne C.

    1994-07-01

    The rate constants for the hydrogen three-body collisional recombination reaction with atomic and molecular hydrogen acting as third bodies have been determined by numerous investigators during the past 30 yr, but these rates exhibit significant scatter. The discrepancies in the rate constants determined by different investigators are as great as two orders of magnitude in the temperature range of interest for nuclear thermal rocket (NTR) operation, namely, 2000-3300 K. The impact of this scatter on our ability to predict the specific impulse (I(sub sp)) delivered by a 30-klbf NTR has been determined for chamber pressures and temperatures from, respectively, 20-1000 psia and 2700-3300 K. The variation in I(sub sp) produced by using the different rate constants is as great as 10%, or 100 s. This variation also obscures the influence of chamber pressure on I(sub sp); using fast kinetics, low pressures yield significantly improved performance, while using slow or nominal kinetics, the pressure dependence of I(sub sp) is negligible. Because the flow composition freezes at very small area ratios, optimization of the nozzle contour in the near-throat region maximizes recombination. Vibrational relaxation is found to produce negligible losses in I(sub sp).

  8. Experimental Investigation on Performance of Pulse Detonation Rocket Engine Model

    Institute of Scientific and Technical Information of China (English)

    LI Qiang; FAN Wei; YAN Chuan-jun; HU Cheng-qi; YE Bin

    2007-01-01

    The PDRE test model used in these experiments utilized kerosene as the fuel, oxygen as oxidizer, and nitrogen as purge gas. The solenoid valves were employed to control intermittent supplies of kerosene, oxygen and purge gas. PDRE test model was 50 mm in inner diameter by 1.2 m long. The DDT (defiagration to detonation transition) enhancement device Shchelkin spiral was used in the test model.The effects of detonation frequency on its time-averaged thrust and specific impulse were experimentally investigated. The obtained results showes that the time-averaged thrust of PDRE test model was approximately proportional to the detonation frequency. For the detonation frequency 20 Hz, the time-averaged thrust was around 107 N, and the specific impulse was around 125 s. The nozzle experiments were conducted using PDRE test model with three traditional nozzles. The experimental results obtained demonstrated that all of those nozzles could augment the thrust and specific impulse. Among those three nozzles, the convergent nozzle had the largest increased augmentation, which was approximately 18%, under the specific condition of the experiment.

  9. Internal Flow Simulation of High-Performance Solid Rockets using a k-ωTurbulence Model

    Institute of Scientific and Technical Information of China (English)

    V.R. SANAL KUMAR; H.D. KIM; B.N. RAGHUNANDAN; T. SETOGUCHI; S. RAGHUNATHAN

    2005-01-01

    @@ For technological reasons many high-performance solid rocket motors are made from segmented propellant grains with non-uniform port geometry. In this paper parametric studies have been carried out to examine the geometric dependence of transient flow features in solid rockets with non-uniform ports. Numerical computations have been carried out in an inert simulator of solid propellant rocket motor with the aid of a standard k-ω turbulence model. It was seen that the damping of the temperature fluctuation is faster in solid rocket with convergent port than with divergent port geometry. We inferred that the damping of the flow fluctuations using the port geometry is a meaningful objective for the suppression and control of the instability and/or pressure/thrust oscillations during the starting transient of solid rockets.

  10. Low Erosion Ceramic Composite Liners for Improved Performance of Ablative Rocket Thrust Chambers Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Advanced liquid rocket propulsion systems must achieve longer burn times without performance degradation to allow the lowest cost per kilogram access to space....

  11. Low Erosion Ceramic Composite Liners for Improved Performance of Ablative Rocket Thrust Chambers Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Advanced liquid rocket propulsion systems must achieve longer burn times without performance degradation to allow the lowest cost per kilogram access to space....

  12. Measurement of low-frequency magnetic pulses from negative stepped leaders in rocket-triggered lightning flashes

    Science.gov (United States)

    Lu, Gaopeng

    2017-04-01

    Measurement of low-frequency magnetic pulses from negative stepped leaders in rocket-triggered lightning flashes Gaopeng Lu,1,2 Yanfeng Fan,1,3 Hongbo Zhang,1,3 Rubin Jiang,1,2 Mingyuan Liu,1,2 and Xiushu Qie,1,2 1. Key Laboratory of Middle Atmosphere and Global Environment Observation, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, 100029, China 2. Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, Nanjing University of Information Science and Technology, Nanjing, Jiangsu 210044, China 3. University of Chinese Academy of Sciences, Beijing 100049, China We report the measurement of magnetic pulses from the negative stepped leaders in positive rocket-triggered lightning flashes with the low-frequency (4 kHz to 420 kHz) magnetic sensor at two different distances (78 m and 970 m, respectively) during the SHantong Artificial Triggered Lightning Experiments (SHATLE) during summer of 2015. Different from the magnetic radiation from positive leaders as observed in the considerably more frequent cases, the impulsive signals from the negative leader sustain for a much longer time interval, while the attenuation of current pulse launched by the stepping of leader is also observed. The general pattern of magnetic pulses observed for the negative stepped leader is different from the positive counterpart. Also, the initial negative leader appears to be brighter than the positive ones, as shown by both high-speed video observation and the magnetic measurement.

  13. Performance characteristics of pulse tube refrigerators

    Science.gov (United States)

    Huang, B. J.; Tzeng, T. M.

    In the present study experiments were carried out to investigate the performance characteristics of pulse tube refrigerators. It was found that the cool-down time tc during the transient or start-up period is dominated by the time constant of the pulse tube wall τpt and that the dynamics of a basic pulse tube (BPT) refrigerator approaches that of a first-order system. For steady state operation, the cold-end temperature TL was found to vary with τpt, and the cooling load QL increases monotonically with increasing τpt. This indicates that heat pumped by the gas from the cold to the hot end increases with decreasing hpt (i.e. less energy exchange between the gas and wall). The process of heat storage or release of the pulse tube wall is thus shown to have a negative effect on the performance of a BPT refrigerator. It was thus found experimentally that the gas compression/expansion process inside the pulse tube, which is similar to a Brayton cycle but lies between isothermal and adiabatic, can explain the performance of BPT refrigerators. The present experiment also shows that the performance of a pulse tube refrigerator at transient and steady states is mainly dominated by the time constant of the pulse tube wall τpt.

  14. Market Performance of Selected Pulses in Myanmar

    OpenAIRE

    Thaung, Nyein Nyein; Choi, Kyu Seob

    2007-01-01

    This paper shows to investigate the performance and efficiency of marketing system of chick pea, green gram and pigeon pea in each selected townships. This study assessed the marketing channel, distributed marketing margins and spatial market price integration to evaluate the performance of pulses marketing in Myanmar. The result showed that producer received the largest net margin followed by the exporter, town wholesaler, wholesaler in Bayintnaung market and finally by the primary collector...

  15. High energy-density liquid rocket fuel performance

    Science.gov (United States)

    Rapp, Douglas C.

    1990-01-01

    A fuel performance database of liquid hydrocarbons and aluminum-hydrocarbon fuels was compiled using engine parametrics from the Space Transportation Engine Program as a baseline. Propellant performance parameters are introduced. General hydrocarbon fuel performance trends are discussed with respect to hydrogen-to-carbon ratio and heat of formation. Aluminum-hydrocarbon fuel performance is discussed with respect to aluminum metal loading. Hydrocarbon and aluminum-hydrocarbon fuel performance is presented with respect to fuel density, specific impulse and propellant density specific impulse.

  16. Technique for the optimization of the powerhead configuration and performance of liquid rocket engines

    Science.gov (United States)

    St. Germain, Brad David

    The development and optimization of liquid rocket engines is an integral part of space vehicle design, since most Earth-to-orbit launch vehicles to date have used liquid rockets as their main propulsion system. Rocket engine design tools range in fidelity from very simple conceptual level tools to full computational fluid dynamics (CFD) simulations. The level of fidelity of interest in this research is a design tool that determines engine thrust and specific impulse as well as models the powerhead of the engine. This is the highest level of fidelity applicable to a conceptual level design environment where faster running analyses are desired. The optimization of liquid rocket engines using a powerhead analysis tool is a difficult problem, because it involves both continuous and discrete inputs as well as a nonlinear design space. Example continuous inputs are the main combustion chamber pressure, nozzle area ratio, engine mixture ratio, and desired thrust. Example discrete variable inputs are the engine cycle (staged-combustion, gas generator, etc.), fuel/oxidizer combination, and engine material choices. Nonlinear optimization problems involving both continuous and discrete inputs are referred to as Mixed-Integer Nonlinear Programming (MINLP) problems. Many methods exist in literature for solving MINLP problems; however none are applicable for this research. All of the existing MINLP methods require the relaxation of the discrete variables as part of their analysis procedure. This means that the discrete choices must be evaluated at non-discrete values. This is not possible with an engine powerhead design code. Therefore, a new optimization method was developed that uses modified response surface equations to provide lower bounds of the continuous design space for each unique discrete variable combination. These lower bounds are then used to efficiently solve the optimization problem. The new optimization procedure was used to find optimal rocket engine designs

  17. Numerical Simulation of Pulse Detonation Rocket-Induced MHD Ejector (PDRIME) Concepts for Advanced Propulsion Systems

    Science.gov (United States)

    2012-02-28

    Engineering, 2010. 8 Roth, T., “ Modeling and Numerical Simulations of Pulse Detonation Engines with MHD Thrust Augmentation”, M.S. thesis, Department of...throat, at time 2.3ms. Results are shown for the PDE (blow-down model ) with and without MHD generation in the region between 0.4 and 0.8m from the...down model ) for different values of the exit- to-throat area ratio and for different altitudes, without MHD generation and without the presence of the

  18. Analysis of Viscous Heating in a Micro-Rocket Flow and Performance

    Institute of Scientific and Technical Information of China (English)

    José A. Morí(n)igo; José Hermida Quesada

    2008-01-01

    Micro-rockets for propulsion of small spacecrafts exhibit significant differences with regard to their macroscale counterparts, mainly caused by the role of the viscous dissipation and heat transfer processes in the micron-sized scale. The goal of this work is to simulate the transient operation of a micro-rocket to investigate the effects of viscous heating on the flow and performance for four configurations of the expanding gas and wafer material. The modelling follows a multiphysics approach that solves the fluid and solid regions fully coupled. A continuum-based description that incorporates the effects of gas rarefaction through the micro-nozzle, viscous dissipation and heat transfer at the solid-gas interface is presented. Non-equilibrium is addressed with the implementation of a 2nd-order slip-model for the velocity and temperature at the walls. The results stress that solid-fluid coupling exerts a strong influence on the flowfield and performance as well as the effect of the wafer during the first instants of the transient in micro-rockets made of low and high thermal conductivity materials.

  19. An injector design model for predicting rocket engine performance and heat transfer

    Science.gov (United States)

    Calhoon, D. F.; Kors, D. L.; Gordon, L. H.

    1973-01-01

    A model is formulated for estimating the performance and chamber heat transfer in rocket injectors/chambers operating with gaseous H2-O2 propellants. The model quantifies the combustion performance and chamber heat flux for variables such as chamber length, element type, element area ratio, impingement angle, thrust/element, mixture ratio, moment ratio, element spacing, and physical size. Design equations are given and curves are plotted for evaluation of combustion performance in injectors comprised of F-O-F triplet, premix, coaxial and swirl coaxial element types. Curve plots and equations are also included for estimation of the chamber wall heat fluxes generated by these element types.

  20. Enhancement of hybrid rocket combustion performance using nano-sized energetic particles

    Science.gov (United States)

    Risha, Grant Alexander

    Until now, the regression rate of classical hybrid rocket engines have typically been an order of magnitude lower than solid propellant motors; thus, hybrids require a relatively large fuel surface area for a given thrust level. In addition to low linear regression rates, relatively low combustion efficiency (87 to 92%), low mass burning rates, varying oxidizer-to-fuel ratio during operation, and lack of scaling laws have been reported. These disadvantages can be ameliorated by introducing nano-sized energetic powder additives into the solid fuel. The addition of nano-sized energetic particles into the solid fuel enhances performance as measured by parameters such as: density specific impulse, mass and linear burning rates, and thrust. Thermophysical properties of the solid fuel such as density, heat of combustion, thermal diffusivity, and thermal conductivity are also enhanced. The types of nano-sized energetic particles used in this study include aluminum, boron, boron carbide, and some Viton-A coated particles. Since the combustion process of solid fuels in a hybrid rocket engine is governed by the mass flux of the oxidizer entering the combustion chamber, the rate-limiting process is the mixing and reacting of the pyrolysis products of the fuel grain with the incoming oxidizer. The overall goal of this research was to determine the relative propulsive and combustion behavior for a family of newly-developed HTPB-based solid-fuel formulations containing various nano-sized energetic particles. Seventeen formulations contained 13% additive by weight, one formulation (SF4) contained 6.5% additive by weight, and one formulation (SF19) contained 5.65% boron by weight. The two hybrid rocket engines which were used in this investigation were the Long Grain Center-Perforated (LGCP) rocket engine and the X-Ray Transparent Casing (XTC) rocket engine. The smaller scale LGCP rocket engine was used to evaluate all of the formulations because conducting experiments using the

  1. Damage-mitigating control of a reusable rocket engine for high performance and extended life

    Science.gov (United States)

    Ray, Asok; Dai, Xiaowen

    1995-01-01

    The goal of damage mitigating control in reusable rocket engines is to achieve high performance with increased durability of mechanical structures such that functional lives of the critical components are increased. The major benefit is an increase in structural durability with no significant loss of performance. This report investigates the feasibility of damage mitigating control of reusable rocket engines. Phenomenological models of creep and thermo-mechanical fatigue damage have been formulated in the state-variable setting such that these models can be combined with the plant model of a reusable rocket engine, such as the Space Shuttle Main Engine (SSME), for synthesizing an optimal control policy. Specifically, a creep damage model of the main thrust chamber wall is analytically derived based on the theories of sandwich beam and viscoplasticity. This model characterizes progressive bulging-out and incremental thinning of the coolant channel ligament leading to its eventual failure by tensile rupture. The objective is to generate a closed form solution of the wall thin-out phenomenon in real time where the ligament geometry is continuously updated to account for the resulting deformation. The results are in agreement with those obtained from the finite element analyses and experimental observation for both Oxygen Free High Conductivity (OFHC) copper and a copper-zerconium-silver alloy called NARloy-Z. Due to its computational efficiency, this damage model is suitable for on-line applications of life prediction and damage mitigating control, and also permits parametric studies for off-line synthesis of damage mitigating control systems. The results are presented to demonstrate the potential of life extension of reusable rocket engines via damage mitigating control. The control system has also been simulated on a testbed to observe how the damage at different critical points can be traded off without any significant loss of engine performance. The research work

  2. Solid amine-boranes as high performance hypergolic hybrid rocket fuels

    Science.gov (United States)

    Pfeil, Mark A.

    Hypergolic hybrid rockets have the potential of providing systems that are simple, reliable, have high performance, and allow for energy management. Such a propulsion system can be applied to fields that need a single tactical motor with flexible mission requirements of either high speed to target or extended loitering. They also provide the possibility for alternative fast response dynamic altitude control systems if ignition delays are sufficiently short. Amines are the traditional fuel of choice when selecting a hypergolic combination as these tend to react readily with both nitric acid and dinitrogen tertroxide based oxidizers. It has been found that the addition of a borane adduct to an amine fuel tends to reduce the ignition delay by up to an order of magnitude with white fuming nitric acid (WFNA). The borane addition has resulted in fuels with very short ignition delays between 2-10 ms - the fastest times for an amine based fuel reacting with nitric acid based oxidizers. The incorporation of these amine-boranes, specifically ethylenediamine bisborane (EDBB), into various fuel binders has also been found to result in ignition delays between 3-10 ms - the fastest times again for amine based fuels. It was found that the addition of a borane to an amine increased theoretical performance of the amine resulting in high performance fuels. The amine-borane/fuel binder combinations also produced higher theoretical performance values than previously used hypergolic hybrid rockets. Some of the theoretical values are on par or higher than the current toxic liquid hypergolic fuels, making amine boranes an attractive replacement. The higher performing amine-borane/fuel binder combinations also have higher performance values than the traditional rocket fuels, excluding liquid hydrogen. Thus, amine-borane based fuels have the potential to influence various area in the rocket field. An EDBB/ferrocene/epoxy fuel was tested in a hypergolic hybrid with pure nitric acid as the

  3. Overview of initial research into the effects of strong vortex flow on hybrid rocket combustion and performance

    Science.gov (United States)

    Gloyer, P.; Knuth, William H.; Goodman, J.

    1993-01-01

    An examination of the effect of vortex flow on hybrid rocket combustion and performance is underway. Emphasis is on response of the fuel regression rate when subjected to vortex flow. Initial results show that there is a definite effect of the vortex on fuel regression rate. Future work will focus on quantitatively measuring this regression rate. This work is part of an overall program to develop an ultra low cost fuel system for hybrid rocket engines.

  4. Parametric study and performance analysis of hybrid rocket motors with double-tube configuration

    Science.gov (United States)

    Yu, Nanjia; Zhao, Bo; Lorente, Arnau Pons; Wang, Jue

    2017-03-01

    The practical implementation of hybrid rocket motors has historically been hampered by the slow regression rate of the solid fuel. In recent years, the research on advanced injector designs has achieved notable results in the enhancement of the regression rate and combustion efficiency of hybrid rockets. Following this path, this work studies a new configuration called double-tube characterized by injecting the gaseous oxidizer through a head end injector and an inner tube with injector holes distributed along the motor longitudinal axis. This design has demonstrated a significant potential for improving the performance of hybrid rockets by means of a better mixing of the species achieved through a customized injection of the oxidizer. Indeed, the CFD analysis of the double-tube configuration has revealed that this design may increase the regression rate over 50% with respect to the same motor with a conventional axial showerhead injector. However, in order to fully exploit the advantages of the double-tube concept, it is necessary to acquire a deeper understanding of the influence of the different design parameters in the overall performance. In this way, a parametric study is carried out taking into account the variation of the oxidizer mass flux rate, the ratio of oxidizer mass flow rate injected through the inner tube to the total oxidizer mass flow rate, and injection angle. The data for the analysis have been gathered from a large series of three-dimensional numerical simulations that considered the changes in the design parameters. The propellant combination adopted consists of gaseous oxygen as oxidizer and high-density polyethylene as solid fuel. Furthermore, the numerical model comprises Navier-Stokes equations, k-ε turbulence model, eddy-dissipation combustion model and solid-fuel pyrolysis, which is computed through user-defined functions. This numerical model was previously validated by analyzing the computational and experimental results obtained for

  5. Performance characteristics of LOX-H2, tangential-entry, swirl-coaxial, rocket injectors

    Science.gov (United States)

    Howell, Doug; Petersen, Eric; Clark, Jim

    1993-01-01

    Development of a high performing swirl-coaxial injector requires an understanding of fundamental performance characteristics. This paper addresses the findings of studies on cold flow atomic characterizations which provided information on the influence of fluid properties and element operating conditions on the produced droplet sprays. These findings are applied to actual rocket conditions. The performance characteristics of swirl-coaxial injection elements under multi-element hot-fire conditions were obtained by analysis of combustion performance data from three separate test series. The injection elements are described and test results are analyzed using multi-variable linear regression. A direct comparison of test results indicated that reduced fuel injection velocity improved injection element performance through improved propellant mixing.

  6. Optimizing the Thermoacoustic Pulse Tube Refrigerator Performances

    Directory of Open Access Journals (Sweden)

    E. V. Blagin

    2014-01-01

    Full Text Available The article deals with research and optimization of the thermoacoustic pulse tube refrigerator to reach a cryogenic temperature level. The refrigerator is considered as a thermoacoustic converter based on the modified Stirling cycle with helium working fluid. A sound pressure generator runs as a compressor. Plant model comprises an inner heat exchanger, a regenerative heat exchanger, a pulse tube, hot and cold heat exchangers at its ends, an inertial tube with the throttle, and a reservoir. A model to calculate the pulse tube thermoacoustic refrigerator using the DeltaEC software package has been developed to be a basis for calculation techniques of the pulse tube refrigerator. Momentum, continuity, and energy equations for helium refrigerant are solved according to calculation algorithm taking into account the porosity of regenerator and heat exchangers. Optimization of the main geometric parameters resulted in decreasing temperature of cold heat exchanger by 41,7 K. After optimization this value became equal to 115,01 K. The following parameters have been optimized: diameters of the feeding and pulse tube and heat exchangers, regenerator, lengths of the regenerator and pulse and inertial tubes, as well as initial pressure. Besides, global minimum of temperatures has been searched at a point of local minima corresponding to the optimal values of abovementioned parameters. A global-local minima difference is 0,1%. Optimized geometric and working parameters of the thermoacoustic pulse tube refrigerator are presented.

  7. Performance of a tapered pulse tube

    Energy Technology Data Exchange (ETDEWEB)

    Swift, G.; Allen, M.; Woolan, J.J. [Cryenco Inc., Denver, CO (United States)

    1998-02-01

    In a well instrumented pulse tube refrigerator having 1,500 W of cooling power at 125 K, the authors have measured the figure of merit of a tapered pulse tube at several operating points. At operating points near the operating point for which the taper was designed, the figure of merit is 0.96. This is close to the theoretical optimum figure of merit 0.97 calculated for this pulse tube considering only two loss mechanisms: heat conduction in the metal pulse tube wall and ordinary thermoacoustic heat transport in the gas within a few thermal penetration depths of the wall. At operating points farther from the design operating point, the measured figure of merit is much lower, as streaming driven convection adds a third loss mechanism.

  8. Performance of a tapered pulse tube

    Energy Technology Data Exchange (ETDEWEB)

    Swift, G.; Allen, M.; Woolan, J.J. [Cryenco Inc., Denver, CO (United States)

    1998-02-01

    In a well instrumented pulse tube refrigerator having 1,500 W of cooling power at 125 K, the authors have measured the figure of merit of a tapered pulse tube at several operating points. At operating points near the operating point for which the taper was designed, the figure of merit is 0.96. This is close to the theoretical optimum figure of merit 0.97 calculated for this pulse tube considering only two loss mechanisms: heat conduction in the metal pulse tube wall and ordinary thermoacoustic heat transport in the gas within a few thermal penetration depths of the wall. At operating points farther from the design operating point, the measured figure of merit is much lower, as streaming driven convection adds a third loss mechanism.

  9. Effect of grain port length-diameter ratio on combustion performance in hybrid rocket motors

    Science.gov (United States)

    Cai, Guobiao; Zhang, Yuanjun; Tian, Hui; Wang, Pengfei; Yu, Nanjia

    2016-11-01

    The objectives of this study are to develop a more accurate regression rate considering the oxidizer mass flow and the fuel grain geometry configuration with numerical and experimental investigations in polyethylene (PE)/90% hydrogen peroxide (HP) hybrid rocket. Firstly, a 2-D axisymmetric CFD model with turbulence, chemistry reaction, solid-gas coupling is built to investigate the combustion chamber internal flow structure. Then a more accurate regression formula is proposed and the combustion efficiency changing with the length-diameter ratio is studied. A series experiments are conducted in various oxidizer mass flow to analyze combustion performance including the regression rate and combustion efficiency. The regression rates are measured by the fuel mass reducing and diameter changing. A new regression rate formula considering the fuel grain configuration is proposed in this paper. The combustion efficiency increases with the length-diameter ratio changing. To improve the performance of a hybrid rocket motor, the port length-diameter ratio is suggested 10-12 in the paper.

  10. Fundamentals of aircraft and rocket propulsion

    CERN Document Server

    El-Sayed, Ahmed F

    2016-01-01

    This book provides a comprehensive basics-to-advanced course in an aero-thermal science vital to the design of engines for either type of craft. The text classifies engines powering aircraft and single/multi-stage rockets, and derives performance parameters for both from basic aerodynamics and thermodynamics laws. Each type of engine is analyzed for optimum performance goals, and mission-appropriate engines selection is explained. Fundamentals of Aircraft and Rocket Propulsion provides information about and analyses of: thermodynamic cycles of shaft engines (piston, turboprop, turboshaft and propfan); jet engines (pulsejet, pulse detonation engine, ramjet, scramjet, turbojet and turbofan); chemical and non-chemical rocket engines; conceptual design of modular rocket engines (combustor, nozzle and turbopumps); and conceptual design of different modules of aero-engines in their design and off-design state. Aimed at graduate and final-year undergraduate students, this textbook provides a thorough grounding in th...

  11. Pulse Combustors—Performance and Control

    Institute of Scientific and Technical Information of China (English)

    MichaelZeutzius; ToshiakiSetoguchi; 等

    2000-01-01

    Limited resources of fossil energy require the search for new energy conversion preocesses and the increase of the efficiency of power plants to ensure the energy household in the future,Basically,changing the combustion mode from steady to pulse combustion makes an enormous reduction of fuel consumption possible,Active control systems for pulse combustors installed into the inlet further improve the efficiency and extend the operating range considerably.The control algorithm including fuel rate-air rate-pressure characteristics and control strategies as well are presented.

  12. Flight Investigation of the Performance of a Two-stage Solid-propellant Nike-deacon (DAN) Meteorological Sounding Rocket

    Science.gov (United States)

    Heitkotter, Robert H

    1956-01-01

    A flight investigation of two Nike-Deacon (DAN) two-stage solid-propellant rocket vehicles indicated satisfactory performance may be expected from the DAN meteorological sounding rocket. Peak altitudes of 356,000 and 350,000 feet, respectively, were recorded for the two flight tests when both vehicles were launched from sea level at an elevation angle of 75 degrees. Performance calculations based on flight-test results show that altitudes between 358,000 feet and 487,000 feet may be attained with payloads varying between 60 pounds and 10 pounds.

  13. Design and evaluation of high performance rocket engine injectors for use with hydrocarbon fuels

    Science.gov (United States)

    Pavli, A. J.

    1979-01-01

    An experimental program to determine the feasibility of using a heavy hydrocarbon fuel as a rocket propellant is reported herein. A method of predicting performance of a heavy hydrocarbon in terms of vaporization effectiveness is described and compared to other fuels and to experimental test results. The work was done at a chamber pressure of 4137 KN/sq M (600 psia) with RP-1, JP-10, and liquefied natural gas as fuels, and liquid oxygen as the oxidizer. Combustion length effects were explored over a range of 21.6 cm (8 1/2 in.) to 55.9 cm (22 in.). Four injector types were tested, each over a range of mixture ratios. Further configuration modifications were obtained by 'reaming' each injector several times to provide test data over a range of injector pressure drop.

  14. Design and evaluation of high performance rocket engine injectors for use with hydrocarbon fuels

    Science.gov (United States)

    Pavli, A. J.

    1979-01-01

    The feasibility of using a heavy hydrocarbon fuel as a rocket propellant is examined. A method of predicting performance of a heavy hydrocarbon in terms of vaporization effectiveness is described and compared to other fuels and to experimental test results. Experiments were done at a chamber pressure of 4137 KN/sq M (600 psia) with RP-1, JP-10, and liquefied natural gas as fuels, and liquid oxygen as the oxidizer. Combustion length effects were explored over a range of 21.6 cm (8 1/2 in) to 55.9 cm (22 in). Four injector types were tested, each over a range of mixture ratios. Further configuration modifications were obtained by reaming each injector several times to provide test data over a range of injector pressure drop.

  15. Performance Studies on Sub-cooling of Cryogenic Liquids Used for Rocket Propulsion Using Helium Bubbling

    Directory of Open Access Journals (Sweden)

    Ramesh T

    2014-03-01

    Full Text Available The sub-cooling of cryogenic propellants contained in tanks is an important and effective method for bringing down the lift-off mass of launch vehicle and thus the performance of the rocket engine is greatly improved. This paper presents the technical and experimental studies conducted on cryogenic liquids such as Liquid Oxygen, Liquid Nitrogen, and Liquid Hydrogen using helium bubbling method. The influence of cooled Helium on the degree of sub-cooling and the variation in flow rate of Helium gas admitted are discussed. The experimental and theoretical studies indicate that the sub-cooling technique using helium injection is a very simple method and can be very well adopted in propellant tanks used for ground and launch vehicle applications.

  16. Rocket-powered high-performance liquid chromatographic analysis of plant ascorbate and glutathione.

    Science.gov (United States)

    Davey, M W; Dekempeneer, E; Keulemans, J

    2003-05-01

    We describe a robust procedure for the extraction and high-performance liquid chromatographic analysis of L-ascorbate (vitamin C), glutathione (gamma-glutamyl cysteinylglycine), and their respective oxidized forms from various plant tissues. Parameters such as the choice of extraction buffer, tissue disruption technique, sample stability, and separation conditions have all been optimized. In particular we found that the inclusion of the reducing agent dithiothreitol as a "stabilizer" in extracts with high phenolic content actually promoted oxidation of these antioxidants. Further, by using commercially available short "Rocket" HPLC columns in combination with high mobile-phase flow rates, analysis times were reduced to only 6min, making the method suitable for the high-resolution screening of large numbers of samples.

  17. 脉冲发动机隔离装置发展现状研究%Research on the Development of Separation Device in Pulse Soild Rocket Motor

    Institute of Scientific and Technical Information of China (English)

    王春光; 刘洪超; 杨德敏

    2012-01-01

    分析了国外脉冲发动机隔离装置的结构,并按照各自特点进行分类,主要分为:非金属易碎式、喷射棒式、金属膜片式、非金属材料隔舱、隔层式。详细阐述了国内双脉冲发动机的研究进展,并分析了各种隔离装置的优缺点及与国外的差距,最后为国内脉冲发动机的发展提出了几点建议。%This paper analyzes the pulse separation device of external double pulse motor, which can be divided into five categories according to respective characteristics, including non-metallic frangible mode ,jet rod mode, metal piece mode, non-metallic material mode and soft mode. The paper expounds research status of domestic double pulse motor, analyzes the advantages and disadvantages of various types of pulse separation device, and points out the gaps with foreign countries in the study. At last, it gives suggestions for future development of domestic research on pulse solid rocket motor.

  18. Single and Multi-Pulse Low-Energy Conical Theta Pinch Inductive Pulsed Plasma Thruster Performance

    Science.gov (United States)

    Hallock, Ashley K.; Martin, Adam; Polzin, Kurt; Kimberlin, Adam; Eskridge, Richard

    2013-01-01

    Fabricated and tested CTP IPPTs at cone angles of 20deg, 38deg, and 60deg, and performed direct single-pulse impulse bit measurements with continuous gas flow. Single pulse performance highest for 38deg angle with impulse bit of approx.1 mN-s for both argon and xenon. Estimated efficiencies low, but not unexpectedly so based on historical data trends and the direction of the force vector in the CTP. Capacitor charging system assembled to provide rapid recharging of capacitor bank, permitting repetition-rate operation. IPPT operated at repetition-rate of 5 Hz, at maximum average power of 2.5 kW, representing to our knowledge the highest average power for a repetitively-pulsed thruster. Average thrust in repetition-rate mode (at 5 kV, 75 sccm argon) was greater than simply multiplying the single-pulse impulse bit and the repetition rate.

  19. Scaling study of the combustion performance of gas-gas rocket injectors

    Institute of Scientific and Technical Information of China (English)

    Wang Xiao-Wei; Cai Guo-Biao; Jin Ping

    2011-01-01

    To obtain the key subelements that may influence the scaling of gas-gas injector combustor performance,the combustion performance subelements in a liquid propellant rocket engine combustor are initially analysed based on the results of a previous study on the scaling of a gas-gas combustion flowfield.Analysis indicates that inner wall friction loss and heat-flux loss are two key issues in gaining the scaling criterion of the combustion performance.The similarity conditions of the inner wall friction loss and heat-flux loss in a gas-gas combustion chamber are obtained by theoretical analyses.Then the theoretical scaling criterion was obtained for the combustion performance,but it proved to be impractical.The criterion conditions,the wall friction and the heat flux are further analysed in detail to obtain the specific engineering scaling criterion of the combustion performance.The results indicate that when the inner flowfields in the combustors are similar,the combustor wall shear stress will have similar distributions qualitatively and will be directly proportional to pc08dt-0.2 quantitatively.In addition,the combustion peformance will remain unchanged.Furthermore,multi-element injector chambers with different geometric sizes and at different pressures are numerically simulated and the wall shear stress and combustion efficiencies are solved and compared with each other.A multielement injector chamber is designed and hot-fire tested at several chamber pressures and the combustion performances are measured in a total of nine hot-fire tests.The numerical and experimental results verified the similarities among combustor wall shear stress and combustion performances at different chamber pressures and geometries,with the criterion applied.

  20. An approach to selection of material and manufacturing processes for rocket motor cases using weighted performance index

    Science.gov (United States)

    Rajan, K. M.; Narasimhan, K.

    2002-08-01

    Material selection is a very critical design decision, which has a profound influence on the entire development program for rocket motor cases. In the selection process, the main performance parameters and the most appropriate fabrication technology with proven processes must be considered. Many years of practical experience in material selection process with a thorough understanding of materials behavior under various loading environments and hands-on experiences with various available manufacturing processes are of immense help to the design and development engineer for successful completion of the development program. In this paper, an attempt has been made to present an approach for selecting appropriate material and manufacturing process for rocket motor case based on method of Weighted Performance Index (WPI) with the hope that this approach will also provide additional aid to the design engineer for the selection of material and manufacturing process for rocket motor cases. In this method, different properties are assigned a certain weight depending upon their importance to the service requirements. Different properties are normalized using a scaling factor, and finally a weighted property index is computed. The material that scored the maximum numerical value is chosen as the material for fabrication. This approach closely matches with the actual performance. Maraging steel and D6AC are found to be the preferred materials for rocket motor cases for critical missions. HSLA steels are appropriate for less-critical applications, in which rocket motor cases are required in very large numbers (e.g., flow-formed AISI 4130 motor cases[8]). For the selection of an appropriate manufacturing method, the major parameters considered are dimensional accuracy, cost of production, minimum material waste, and flexibility in design. Again, these properties are given a relative grading, which is then converted into a scaled property. Finally, the weighted performance indices

  1. Solid propellant rocket motor internal ballistics performance variation analysis, phase 3

    Science.gov (United States)

    Sforzini, R. H.; Foster, W. A., Jr.; Murph, J. E.; Adams, G. W., Jr.

    1977-01-01

    Results of research aimed at improving the predictability of off nominal internal ballistics performance of solid propellant rocket motors (SRMs) including thrust imbalance between two SRMs firing in parallel are reported. The potential effects of nozzle throat erosion on internal ballistic performance were studied and a propellant burning rate low postulated. The propellant burning rate model when coupled with the grain deformation model permits an excellent match between theoretical results and test data for the Titan IIIC, TU455.02, and the first Space Shuttle SRM (DM-1). Analysis of star grain deformation using an experimental model and a finite element model shows the star grain deformation effects for the Space Shuttle to be small in comparison to those of the circular perforated grain. An alternative technique was developed for predicting thrust imbalance without recourse to the Monte Carlo computer program. A scaling relationship used to relate theoretical results to test results may be applied to the alternative technique of predicting thrust imbalance or to the Monte Carlo evaluation. Extended investigation into the effect of strain rate on propellant burning rate leads to the conclusion that the thermoelastic effect is generally negligible for both steadily increasing pressure loads and oscillatory loads.

  2. Rocket propulsion elements - An introduction to the engineering of rockets (6th revised and enlarged edition)

    Science.gov (United States)

    Sutton, George P.

    The subject of rocket propulsion is treated with emphasis on the basic technology, performance, and design rationale. Attention is given to definitions and fundamentals, nozzle theory and thermodynamic relations, heat transfer, flight performance, chemical rocket propellant performance analysis, and liquid propellant rocket engine fundamentals. The discussion also covers solid propellant rocket fundamentals, hybrid propellant rockets, thrust vector control, selection of rocket propulsion systems, electric propulsion, and rocket testing.

  3. Advanced Materials and Manufacturing for Low-Cost, High-Performance Liquid Rocket Combustion Chambers Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Silicided niobium alloy (C103) combustion chambers have been used extensively in both NASA and DoD liquid rocket propulsion systems. Niobium alloys offer a good...

  4. Solid-propellant rocket motor internal ballistic performance variation analysis, phase 2

    Science.gov (United States)

    Sforzini, R. H.; Foster, W. A., Jr.

    1976-01-01

    The Monte Carlo method was used to investigate thrust imbalance and its first time derivative throughtout the burning time of pairs of solid rocket motors firing in parallel. Results obtained compare favorably with Titan 3 C flight performance data. Statistical correlations of the thrust imbalance at various times with corresponding nominal trace slopes suggest several alternative methods of predicting thrust imbalance. The effect of circular-perforated grain deformation on internal ballistics is discussed, and a modified design analysis computer program which permits such an evaluation is presented. Comparisons with SRM firings indicate that grain deformation may account for a portion of the so-called scale factor on burning rate between large motors and strand burners or small ballistic test motors. Thermoelastic effects on burning rate are also investigated. Burning surface temperature is calculated by coupling the solid phase energy equation containing a strain rate term with a model of gas phase combustion zone using the Zeldovich-Novozhilov technique. Comparisons of solutions with and without the strain rate term indicate a small but possibly significant effect of the thermoelastic coupling.

  5. Rocket Performance of Red Fuming Nitric Acid with Blends of Norbornadiene, Carene and Cardanol

    Directory of Open Access Journals (Sweden)

    R. Chhibber

    1992-07-01

    Full Text Available The fuel blends of nornornadiene and carene (50:50 by weight and norbornadiene, carene and cardanol (40:40:20 by weight exhibit synergistic hypergolic ignition with red fuming nitric acid (RFNA as oxidiser. These fuel blends have been evaluated by theoretical calculations of performance parameters and subsequently verified by static firing in a 10 kg/sub f/ thruster at a chamber pressure of around 20 atm, using RFNA (with 21 per cent N/sub 2/O/sub 4/ by weight as oxidiser. The theoretical calculations show maximum specific impulse and C*values at the O/F, 3 to be 227.8 s and 1598.7 m/s respectively for the norbornadiene-carene blend. The corresponding values for the norbornadiene, carene and cardanol blend were found to be 226.8 s and 1586.0 m/s respectively at the O/F, 4. For theoretical calculations, the chamber pressure (P/sub c and the exit pressure (P/sub e/0 were assumed to be 20 and 1 atm, respectively. The static firing of the propellants in a 10 kg thruster exhibited smooth pressure-time curves with the experimental C* values in close agreement with those calculated and the non-deposition of carbon in the nozzle. This indicated low combustion instability and high combustion efficiency under rocket conditions (> 0.9. The fuel blends with their low cost and toxicity and relatively high density can replace G-fuel used in several Indian missiles without impairing the performance.

  6. In-Flight Performance of the Polarization Modulator in the CLASP Rocket Experiment

    Science.gov (United States)

    Ishikawa, Shin-nosuke; Shimizu, Toshifumi; Kano, Ryohei; Bando, Takamasa; Ishikawa, Ryoko; Giono, Gabriel; Beabout, Dyana L.; Beabout, Brent L.; Nakayama, Satoshi; Tajima, Takao

    2016-01-01

    We developed a polarization modulation unit (PMU), a motor system to rotate a waveplate continuously. In polarization measurements, the continuous rotating waveplate is an important element as well as a polarization analyzer to record the incident polarization in a time series of camera exposures. The control logic of PMU was originally developed for the next Japanese solar observation satellite SOLAR-C by the SOLAR-C working group. We applied this PMU for the Chromospheric Lyman-alpha SpectroPolarimeter (CLASP). CLASP is a sounding rocket experiment to observe the linear polarization of the Lyman-alpha emission (121.6 nm vacuum ultraviolet) from the upper chromosphere and transition region of the Sun with a high polarization sensitivity of 0.1 % for the first time and investigate their vector magnetic field by the Hanle effect. The driver circuit was developed to optimize the rotation for the CLASP waveplate (12.5 rotations per minute). Rotation non-uniformity of the waveplate causes error in the polarization degree (i.e. scale error) and crosstalk between Stokes components. We confirmed that PMU has superior rotation uniformity in the ground test and the scale error and crosstalk of Stokes Q and U are less than 0.01 %. After PMU was attached to the CLASP instrument, we performed vibration tests and confirmed all PMU functions performance including rotation uniformity did not change. CLASP was successfully launched on September 3, 2015, and PMU functioned well as designed. PMU achieved a good rotation uniformity, and the high precision polarization measurement of CLASP was successfully achieved.

  7. Analysis of Rocket, Ram-Jet, and Turbojet Engines for Supersonic Propulsion of Long-Range Missles. II - Rocket Missile Performance

    Science.gov (United States)

    Huff, Vearl N.; Kerrebrock, Jack

    1954-01-01

    The theoretical performance of a two-stage ballistic rocket mis having a centerbody and two parallel boosters was investigated for J oxygen and ammonia-fluorine propellants. Both power-plant and missi parameters were optimized to give minimum cost on-the basis of the analysis for a range of 5500 nautical miles. After optimum values were found, each parameter was varied independently to determine its effect on performance of the missile. The missile using the ammonia-fluorine propellant weighs about one half as much as a missile using JP4-oxygen. Based on an expected unit cost of fluorine in quantity production, the ammonia-fluorine missile has a substantially lower relative cost than a JP4-oxygen missile. Optimum chamber pressures for both propellant systems and for both the centerbody and boosters were between 450 and 600 pounds per square inch. High design altitudes for the exhaust nozzle are desirable for both the centerbody and boosters. For the centerbody, the design altitude should be between 45,000 and 60,000 feet, with the value for ammonia-fluorine lower than that for JP4-oxygen. For the boosters, the design altitude should be 20,000 to 30,000 feet, with the value for the ammonia-fluorine. missile higher.

  8. Rocket Flight.

    Science.gov (United States)

    Van Evera, Bill; Sterling, Donna R.

    2002-01-01

    Describes an activity for designing, building, and launching rockets that provides students with an intrinsically motivating and real-life application of what could have been classroom-only concepts. Includes rocket design guidelines and a sample grading rubric. (KHR)

  9. Low-Cost High-Performance Non-Toxic Self-Pressurizing Storable Liquid Bi-Propellant Pressure-Fed Rocket Engine Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Exquadrum proposes a high-performance liquid bi-propellant rocket engine that uses propellants that are non-toxic, self-pressurizing, and low cost. The proposed...

  10. Enhanced Large Solid Rocket Motor Understanding Through Performance Margin Testing: RSRM Five-Segment Engineering Test Motor (ETM-3)

    Science.gov (United States)

    Huppi, Hal; Tobias, Mark; Seiler, James

    2003-01-01

    The Five-Segment Engineering Test Motor (ETM-3) is an extended length reusable solid rocket motor (RSRM) intended to increase motor performance and internal environments above the current four-segment RSRM flight motor. The principal purpose of ETM-3 is to provide a test article for RSRM component margin testing. As the RSRM and Space Shuttle in general continue to age, replacing obsolete materials becomes an ever-increasing issue. Having a five-segment motor that provides environments in excess of normal opera- tion allows a mechanism to subject replacement materials to a more severe environment than experienced in flight. Additionally, ETM-3 offers a second design data point from which to develop and/or validate analytical models that currently have some level of empiricism associated with them. These enhanced models have the potential to further the understanding of RSRM motor performance and solid rocket motor (SRM) propulsion in general. Furthermore, these data could be leveraged to support a five-segment booster (FSB) development program should the Space Shuttle program choose to pursue this option for abort mode enhancements during the ascent phase. A tertiary goal of ETM-3 is to challenge both the ATK Thiokol Propulsion and NASA MSFC technical personnel through the design and analysis of a large solid rocket motor without the benefit of a well-established performance database such as the RSRM. The end result of this undertaking will be a more competent and experienced workforce for both organizations. Of particular interest are the motor design characteristics and the systems engineering approach used to conduct a complex yet successful large motor static test. These aspects of ETM-3 and more will be summarized.

  11. The Thermal State Computational Research of the Low-Thrust Oxygen-Methane Gaseous-Propellant Rocket Engine in the Pulse Mode of Operation

    Directory of Open Access Journals (Sweden)

    O. A. Vorozheeva

    2014-01-01

    Full Text Available Currently promising development direction of space propulsion engineering is to use, as spacecraft controls, low-thrust rocket engines (RDTM on clean fuels, such as oxygen-methane. Modern RDTM are characterized by a lack regenerative cooling and pulse mode of operation, during which there is accumulation of heat energy to lead to the high thermal stress of RDTM structural elements. To get an idea about the thermal state of its elements, which further will reduce the number of fire tests is therefore necessary in the development phase of a new product. Accordingly, the aim of this work is the mathematical modeling and computational study of the thermal state of gaseous oxygen-methane propellant RDMT operating in pulse mode.In this paper we consider a model RDTM working on gaseous propellants oxygen-methane in pulse mode.To calculate the temperature field of the chamber wall of model RDMT under consideration is used the mathematical model of non-stationary heat conduction in a two-dimensional axisymmetric formulation that takes into account both the axial heat leakages and the nonstationary processes occurring inside the chamber during pulse operation of RDMT.As a result of numerical study of the thermal state of model RDMT, are obtained the temperature fields during engine operation based on convective, conductive, and radiative mechanisms of heat transfer from the combustion products to the wall.It is shown that the elements of flanges of combustion chamber of model RDMT act as heat sinks structural elements. Temperatures in the wall of the combustion chamber during the engine mode of operation are considered relatively low.Raised temperatures can also occur in the mixing head in the feeding area of the oxidant into the combustion chamber.During engine operation in the area forming the critical section, there is an intensive heating of a wall, which can result in its melting, which in turn will increase the minimum nozzle throat area and hence

  12. Design and evaluation of an oxidant-fuel-ratio-zoned rocket injector for high performance and ablative engine compatibility

    Science.gov (United States)

    Winter, J. M.; Pavli, A. J.; Shinn, A. M., Jr.

    1972-01-01

    A method for temperature control of the combustion gases in the peripheral zone of a rocket combustor which would reduce ablative throat erosion, prevent melting of zirconia throat inserts, and maintain high combustion performance is discussed. Included are techniques for analyzing and predicting zoned injector performance, as well as the philosophy and method for accomplishing an optimum compromise between high performance and reduced effective gas temperature. The experimental work was done with a 1000-lbf rocket engine which used as propellants N2O4 and a blend of 50-percent N2H4 and 50-percent UDMH at 100-psia chamber pressure and an overall O/F of 2.0. The method selected to provide temperature control was to use 30 percent of the propellant to form a peripheral zone of combustion gases at an O/F of 1.31 and 2700 K. The remaining 70 percent of the propellant in the core was at an O/F of 2.45 to keep the overall O/F at 2.0.

  13. Performance comparisons of nuclear thermal rocket and chemical propulsion systems for piloted missions to Phobos/Mars

    Science.gov (United States)

    Borowski, S. K.; Mulac, M. W.; Spurlock, O. F.

    1989-01-01

    Performance capability of nuclear thermal rocket (NTR) and chemical propulsion systems, operating with and without aerobraking, are compared for a selected set of Mars mission opportunities in the 2000 to 2020 timeframe. Both high- and low-energy mission opportunities are investigated. Results are presented as the required initial mass in low earth orbit (IMLEO) to perform the missions. Missions exclusively using chemical propulsion systems have the greatest initial masses. Significant mass reductions are realized by utilizing either aerobrake or NTR technology or both. As mission energy requirements increase, the benefit of implementing aerobrake or NTR technology increases, resulting in IMLEO mass reductions on the order of 60 to 75 percent when compared with all-propulsive chemical missions. By combining both advanced technologies, still greater mass reductions are possible.

  14. Pulse

    Science.gov (United States)

    ... resting for at least 10 minutes. Take the exercise heart rate while you are exercising. ... pulse rate can help determine if the person's heart is pumping. Pulse ... rate gives information about your fitness level and health.

  15. Pulse-modulation imaging-review and performance analysis.

    Science.gov (United States)

    Chen, D G; Matolin, D; Bermak, A; Posch, C

    2011-02-01

    In time-domain or pulse-modulation (PM) imaging, the incident light intensity is not encoded in amounts of charge, voltage, or current as it is in conventional image sensors. Instead, the image data are represented by the timing of pulses or pulse edges. This method of visual information encoding optimizes the phototransduction individually for each pixel by abstaining from imposing a fixed integration time for the entire array. Exceptionally high dynamic range (DR) and improved signal-to-noise ratio (SNR) are immediate benefits of this approach. In particular, DR is no longer limited by the power-supply rails as in conventional complementary metal-oxide semiconductor (CMOS) complementary metal-oxide semiconductor active pixel sensors, thus providing relative immunity to the supply-voltage scaling of modern CMOS technologies. In addition, PM imaging naturally supports pixel-parallel analog-to-digital conversion, thereby enabling high temporal resolution/frame rates or an asynchronous event-based array readout. The applications of PM imaging in emerging areas, such as sensor network, wireless endoscopy, retinal prosthesis, polarization imaging, and energy harvesting are surveyed to demonstrate the effectiveness of PM imaging in low-power, high-performance machine vision, and biomedical applications of the future. The evolving design innovations made in PM imaging, such as high-speed arbitration circuits and ultra-compact processing elements, are expected to have even wider impacts in disciplines beyond CMOS image sensors. This paper thoroughly reviews and classifies all common PM image sensor architectures. Analytical models and a universal figure of merit - image quality and dynamic range to energy complexity factor are proposed to quantitatively assess different PM imagers across the entire spectrum of PM architectures.

  16. Slip-model Performance for Underexpanded Micro-scale Rocket Nozzle Flows

    Institute of Scientific and Technical Information of China (English)

    José A. Morí(n)igo; José Hermida Quesada; Francisco Caballero Requena

    2007-01-01

    In aerospace Micro-ElectroMechanical Systems (MEMS), the characteristic length scale of the flow approaches the molecular mean free path, thus invalidating the continuum description and enforcing the use of particle methods, like the Direct Simulation Monte Carlo (DSMC), to deal with the non-equilibrium regions. Within the slip-regime (0.01<Kn<~0.1) both approaches, continuum and particle-based, seem to behave well in terms of accuracy. The present study summarizes the implementation and results obtained with a 2nd-order slip boundary condition in a Navier-Stokes solver to address the rarefaction near the nozzle walls. Its assessment and application to a cold-gas micro-scale conical nozzle of 300μm throat diameter, discharging into the low-pressure freestream,constitutes the major aim of the work. The slip-model incorporates the velocity slip with thermal creep and temperature jump, thus permitting to deal with non-isothermal flows as well. Results show that the gas experiences an intense rarefaction in the lip vicinity, pointing to the limits of model validity. Furthermore, a strong Mach deceleration is observed, attributed to the rather thick subsonic boundary layer and supersonic bulk heating caused by the viscous dissipation, in contrast with the expansion to occur in large rocket nozzles during underexpanded operation.

  17. Development of a numerical tool to study the mixing phenomenon occurring during mode one operation of a multi-mode ejector-augmented pulsed detonation rocket engine

    Science.gov (United States)

    Dawson, Joshua

    A novel multi-mode implementation of a pulsed detonation engine, put forth by Wilson et al., consists of four modes; each specifically designed to capitalize on flow features unique to the various flow regimes. This design enables the propulsion system to generate thrust through the entire flow regime. The Multi-Mode Ejector-Augmented Pulsed Detonation Rocket Engine operates in mode one during take-off conditions through the acceleration to supersonic speeds. Once the mixing chamber internal flow exceeds supersonic speed, the propulsion system transitions to mode two. While operating in mode two, supersonic air is compressed in the mixing chamber by an upstream propagating detonation wave and then exhausted through the convergent-divergent nozzle. Once the velocity of the air flow within the mixing chamber exceeds the Chapman-Jouguet Mach number, the upstream propagating detonation wave no longer has sufficient energy to propagate upstream and consequently the propulsive system shifts to mode three. As a result of the inability of the detonation wave to propagate upstream, a steady oblique shock system is established just upstream of the convergent-divergent nozzle to initiate combustion. And finally, the propulsion system progresses on to mode four operation, consisting purely of a pulsed detonation rocket for high Mach number flight and use in the upper atmosphere as is needed for orbital insertion. Modes three and four appear to be a fairly significant challenge to implement, while the challenge of implementing modes one and two may prove to be a more practical goal in the near future. A vast number of potential applications exist for a propulsion system that would utilize modes one and two, namely a high Mach number hypersonic cruise vehicle. There is particular interest in the dynamics of mode one operation, which is the subject of this research paper. Several advantages can be obtained by use of this technology. Geometrically the propulsion system is fairly

  18. Comparison of the quantitative analysis performance between pulsed voltage atom probe and pulsed laser atom probe.

    Science.gov (United States)

    Takahashi, J; Kawakami, K; Raabe, D

    2017-01-31

    The difference in quantitative analysis performance between the voltage-mode and laser-mode of a local electrode atom probe (LEAP3000X HR) was investigated using a Fe-Cu binary model alloy. Solute copper atoms in ferritic iron preferentially field evaporate because of their significantly lower evaporation field than the matrix iron, and thus, the apparent concentration of solute copper tends to be lower than the actual concentration. However, in voltage-mode, the apparent concentration was higher than the actual concentration at 40K or less due to a detection loss of matrix iron, and the concentration decreased with increasing specimen temperature due to the preferential evaporation of solute copper. On the other hand, in laser-mode, the apparent concentration never exceeded the actual concentration, even at lower temperatures (20K), and this mode showed better quantitative performance over a wide range of specimen temperatures. These results indicate that the pulsed laser atom probe prevents both detection loss and preferential evaporation under a wide range of measurement conditions.

  19. Mass transfer performance in pulsed disc and doughnut extraction columns

    Directory of Open Access Journals (Sweden)

    M Torab-Mostaedi

    2011-09-01

    Full Text Available Mass transfer performance is presented for a 76 mm diameter pulsed disc and doughnut extraction column for the toluene-acetone-water system. The experiments were carried out for both mass transfer directions. The mass transfer data are interpreted in terms of the axial diffusion model, thus accounting for continuous phase axial dispersion. The effect of operating parameters on the overall volumetric mass transfer coefficients has been investigated. The results show that the column performance increases with an increase in pulsation intensity. At high pulsation intensity, however, the overall volumetric mass transfer coefficient decreases due to the production of very fine dispersed droplets. It was also found that the column performance decreases with both an increase in dispersed phase velocity and a decrease in continuous phase velocity. An empirical correlation for prediction of the continuous phase overall mass transfer coefficient is derived in terms of the overall Sherwood number, Reynolds number and dispersed phase holdup for each mass transfer direction. The prediction of continuous phase overall mass transfer coefficients from the presented correlations is in good agreement with experimental data.

  20. Influence of Structural Parameters on the Performance of Vortex Valve Variable-Thrust Solid Rocket Motor

    Science.gov (United States)

    Wei, Xianggeng; Li, Jiang; He, Guoqiang

    2017-04-01

    The vortex valve solid variable thrust motor is a new solid motor which can achieve Vehicle system trajectory optimization and motor energy management. Numerical calculation was performed to investigate the influence of vortex chamber diameter, vortex chamber shape, and vortex chamber height of the vortex valve solid variable thrust motor on modulation performance. The test results verified that the calculation results are consistent with laboratory results with a maximum error of 9.5%. The research drew the following major conclusions: the optimal modulation performance was achieved in a cylindrical vortex chamber, increasing the vortex chamber diameter improved the modulation performance of the vortex valve solid variable thrust motor, optimal modulation performance could be achieved when the height of the vortex chamber is half of the vortex chamber outlet diameter, and the hot gas control flow could result in an enhancement of modulation performance. The results can provide the basis for establishing the design method of the vortex valve solid variable thrust motor.

  1. Real gas features on the performance of pulse tube cryocoolers

    Science.gov (United States)

    Ju, Y. L.

    2002-05-01

    The working helium gas in a pulse tube cryocooler operating at temperatures down to 80 K is mainly assumed to be an ideal gas. Therefore, the time-variations of the temperature profiles and the position of the gas element traveling with pressure oscillations inside the pulse tube can be readily determined by the law of Poisson function. However, this is certainly invalid for the pulse tube cryocooler operating at temperature range of liquid helium, in which the thermal properties of the helium gas change drastically. The temperature profiles in the regenerator and the pulse tube are strongly affected by the real thermal properties of the helium gas. We derive in this paper, the respective expressions to follow the tracks of the gas elements as they move in the pulse tube, and to reveal the time dependence of the temperature profiles and the position of gas elements traveling with the pressure oscillations inside the pulse tube. The approach is based on the thermodynamic equations for the real gas. We will show that contrary to the ideal gas case there is another term which determines the dynamic behaviors of the temperature distributions and the position of the gas elements. A typical calculation is presented for visualizing the time dependence of the cooling-down processes of the temperature profiles in the pulse tube of a 4K two-stage pulse tube cryocooler from room temperature down to low temperature.

  2. Performance investigation of the pulse and Campbelling modes of a fission chamber using a Poisson pulse train simulation code

    Science.gov (United States)

    Elter, Zs.; Jammes, C.; Pázsit, I.; Pál, L.; Filliatre, P.

    2015-02-01

    The detectors of the neutron flux monitoring system of the foreseen French GEN-IV sodium-cooled fast reactor (SFR) will be high temperature fission chambers placed in the reactor vessel in the vicinity of the core. The operation of a fission chamber over a wide-range neutron flux will be feasible provided that the overlap of the applicability of its pulse and Campbelling operational modes is ensured. This paper addresses the question of the linearity of these two modes and it also presents our recent efforts to develop a specific code for the simulation of fission chamber pulse trains. Our developed simulation code is described and its overall verification is shown. An extensive quantitative investigation was performed to explore the applicability limits of these two standard modes. It was found that for short pulses the overlap between the pulse and Campbelling modes can be guaranteed if the standard deviation of the background noise is not higher than 5% of the pulse amplitude. It was also shown that the Campbelling mode is sensitive to parasitic noise, while the performance of the pulse mode is affected by the stochastic amplitude distributions.

  3. Space Launch System Base Heating Test: Sub-Scale Rocket Engine/Motor Design, Development and Performance Analysis

    Science.gov (United States)

    Mehta, Manish; Seaford, Mark; Kovarik, Brian; Dufrene, Aaron; Solly, Nathan; Kirchner, Robert; Engel, Carl D.

    2014-01-01

    The Space Launch System (SLS) base heating test is broken down into two test programs: (1) Pathfinder and (2) Main Test. The Pathfinder Test Program focuses on the design, development, hot-fire test and performance analyses of the 2% sub-scale SLS core-stage and booster element propulsion systems. The core-stage propulsion system is composed of four gaseous oxygen/hydrogen RS-25D model engines and the booster element is composed of two aluminum-based model solid rocket motors (SRMs). The first section of the paper discusses the motivation and test facility specifications for the test program. The second section briefly investigates the internal flow path of the design. The third section briefly shows the performance of the model RS-25D engines and SRMs for the conducted short duration hot-fire tests. Good agreement is observed based on design prediction analysis and test data. This program is a challenging research and development effort that has not been attempted in 40+ years for a NASA vehicle.

  4. Performance scaling via passive pulse shaping in cavity-enhanced optical parametric chirped-pulse amplification.

    Science.gov (United States)

    Siddiqui, Aleem M; Moses, Jeffrey; Hong, Kyung-Han; Lai, Chien-Jen; Kärtner, Franz X

    2010-06-15

    We show that an enhancement cavity seeded at the full repetition rate of the pump laser can automatically reshape small-signal gain across the interacting pulses in an optical parametric chirped-pulse amplifier for close-to-optimal operation, significantly increasing both the gain bandwidth and the conversion efficiency, in addition to boosting gain for high-repetition-rate amplification. Applied to a degenerate amplifier, the technique can provide an octave-spanning gain bandwidth.

  5. Advanced Materials and Manufacturing for Low-Cost, High-Performance Liquid Rocket Combustion Chambers, Phase II Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Silicided niobium alloy (C103) combustion chambers have been used extensively in both NASA and DoD liquid rocket propulsion systems. Niobium alloys offer a good...

  6. Assessment of tbe Performance of Ablative Insulators Under Realistic Solid Rocket Motor Operating Conditions (a Doctoral Dissertation)

    Science.gov (United States)

    Martin, Heath Thomas

    2013-01-01

    Ablative insulators are used in the interior surfaces of solid rocket motors to prevent the mechanical structure of the rocket from failing due to intense heating by the high-temperature solid-propellant combustion products. The complexity of the ablation process underscores the need for ablative material response data procured from a realistic solid rocket motor environment, where all of the potential contributions to material degradation are present and in their appropriate proportions. For this purpose, the present study examines ablative material behavior in a laboratory-scale solid rocket motor. The test apparatus includes a planar, two-dimensional flow channel in which flat ablative material samples are installed downstream of an aluminized solid propellant grain and imaged via real-time X-ray radiography. In this way, the in-situ transient thermal response of an ablator to all of the thermal, chemical, and mechanical erosion mechanisms present in a solid rocket environment can be observed and recorded. The ablative material is instrumented with multiple micro-thermocouples, so that in-depth temperature histories are known. Both total heat flux and thermal radiation flux gauges have been designed, fabricated, and tested to characterize the thermal environment to which the ablative material samples are exposed. These tests not only allow different ablative materials to be compared in a realistic solid rocket motor environment but also improve the understanding of the mechanisms that influence the erosion behavior of a given ablative material.

  7. A modular ducted rocket missile model for threat and performance assessment

    NARCIS (Netherlands)

    Mayer, A.E.H.J.; Halswijk, W.H.C.; Komduur, H.J.; Lauzon, M.; Stowe, R.A.

    2005-01-01

    A model was developed to predict the thrust of throttled ramjet propelled missiles. The model is called DRCORE and fulfils the growing need to predict the performance of air breathing missiles. Each subsystem of the propulsion unit of this model is coded by using engineering formulae and enables the

  8. Improved beamforming performance using pulsed plane wave decomposition

    DEFF Research Database (Denmark)

    Munk, Peter; Jensen, Jørgen Arendt

    2000-01-01

    A tool for calculating the beamformer setup associated with a specified pulsed acoustic field is presented. The method is named Pulsed Plane Wave Decomposition (PPWD) and is based on the decomposition of a pulsed acoustic field into a set of PPWs at a given depth. Each PPW can be propagated...... to the location of the elements of an array transducer by a time delay. The contribution of each propagated PPW is summed to form one time function for each array element (the BMF matrix). This approach gives the beamformer setup needed to obtain a close approximation to the desired bounded pulsed acoustic field...... without involving any optimization scheme. The approximation arises due to the limited size of the acoustic aperture and the spatial sampling property of the array transducer. Thus, the acoustical field can be designed according to the imaging needs. The method is demonstrated by examples in the 2D space...

  9. Pulsed UV lamp performance and comparison with UV mercury lamps

    National Research Council Canada - National Science Library

    Schaefer, Raymond; Grapperhaus, Michael; Schaefer, Ian; Linden, Karl

    2007-01-01

    Pulsed lamps based on electric discharges in xenon are of interest for water treatment because they are free of mercury, have instant-on capability, and may provide enhanced effects due to the high...

  10. Eight Pulse Performance of DARHT Axis II - Preliminary Results

    Energy Technology Data Exchange (ETDEWEB)

    Schulze, Martin E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-12-08

    The DARHT-II accelerator produces a 1.65-kA, 17-MeV beam in a 1600-ns pulse. Standard operation of the DARHT Axis II accelerator involves extracting four short pulses from the 1.6 us long macro-pulse produced by the LIA. The four short pulses are extracted using a fast kicker in combination with a quadrupole septum magnet and then transported for several meters to a high-Z material target for conversion to x-rays for radiography. The ability of the DARHT Axis 2 kicker to produce more than the standard four pulse format has been previously demonstrated. This capability was developed to study potential risks associated with beam transport during an initial commissioning phase at low energy (8 MeV) and low current (1.0 kA).The ability of the kicker to deliver more than four pulses to the target has been realized for many years. This note describes the initial results demonstrating this capability.

  11. Theoretical performance of JP-4 fuel and liquid oxygen as a rocket propellant II : equilibrium composition

    Science.gov (United States)

    Huff, Vearl N; Fortini, Anthony; Gordon, Sanford

    1956-01-01

    Data were calculated for equivalence ratios of 1 to 3, chamber pressures of 300 and 600 pounds per square inch absolute, and pressure ratios of 1 to 1500. Parameters included are specific impulse, combustion and exit temperature, molecular weight, characteristic velocity, coefficient of thrust, ratio of nozzle-exit area to throat area, specific heat at constant pressure, isentropic exponent, viscosity, and thermal conductivity. A correlation is given which permits determination of performance for a wide range of chamber pressures.

  12. A unified Navier-Stokes flowfield and performance analysis of liquid rocket engines

    Science.gov (United States)

    Wang, Ten-See; Chen, Yen-Sen

    1990-07-01

    To improve the current composite solutions in the design and analysis of liquid propulsive engines, a computational fluid dynamics model capable of calculating the nonreacting and reacting flows from the combustion chamber, through the nozzle to the external plume, was developed. The Space Shuttle Main Engine (SSME) fired at sea level, along with the flowfields of several other nozzles were investigated. The bell-shaped SSME nozzle was run at 100 percent power level at various flow conditions, the computed flow results and performance compared well with those of other standard codes and engine hot fire test data.

  13. Performance of high area ratio nozzles for a small rocket thruster

    Science.gov (United States)

    Kushida, R. O.; Hermel, J.; Apfel, S.; Zydowicz, M.

    1986-01-01

    Theoretical estimates of supersonic nozzle performance have been compared to experimental test data for nozzles with an area ratio of 100:1 conical and 300:1 optimum contour, and 300:1 nozzles cut off at 200:1 and 100:1. These tests were done on a Hughes Aircraft Company 5 lbf monopropellant hydrazine thruster with chamber pressures ranging from 25 to 135 psia. The analytic method used is the conventional inviscid method of characteristic with correction for laminar boundary layer displacement and drag. Replacing the 100:1 conical nozzle with the 300:1 contoured nozzle resulted in an improvement in thrust performance of 0.74 percent at chamber pressure of 25 psia to 2.14 percent at chamber pressure of 135 psia. The data is significant because it is experimental verification that conventional nozzle design techniques are applicable even where the boundary layer is laminar and displaces as much as 35 percent of the flow at the nozzle exit plane.

  14. Impact of Dissociation and Sensible Heat Release on Pulse Detonation and Gas Turbine Engine Performance

    Science.gov (United States)

    Povinelli, Louis A.

    2001-01-01

    A thermodynamic cycle analysis of the effect of sensible heat release on the relative performance of pulse detonation and gas turbine engines is presented. Dissociation losses in the PDE (Pulse Detonation Engine) are found to cause a substantial decrease in engine performance parameters.

  15. High-performance pulsed magnets: Theory, design and construction

    Science.gov (United States)

    Li, Liang

    This thesis is an in-depth study of the design and construction of coils for pulsed magnets energised by a capacitor bank, including mathematical modelling and testing of the coils. The magnetic field generated by solenoid magnets with homogeneous and non-homogenous current distribution is calculated with the elliptical integral method. Coupled partial differential equations for magnetic and thermal diffusion and the electric circuits are solved numerically to calculate the pulse shape and the heating in a pulsed magnet. The calculations are in good agreement with test results for a large range of different coils; this provides useful insights for optimised coil design. Stresses and strains in the mid-plane of the coil are analytically calculated by solving the system of equations describing the displacement in each layer of the coil. Non-linear stress-strain characteristics and the propagation of the plastic deformation are taken into account by sub- dividing each layer of the coil in the radial direction and changing the elastic-plastic matrix at each transition point. Conductors, insulating materials and techniques used for pulsed magnets are discussed in detail. More than 80 pulsed magnets with optimised combinations of conductors and reinforcements have been built and tested, with peak fields in the range 45-73 T and a bore size from 8 mm-35 mm. The pulse duration is of the order of 10 milliseconds. A dual stage pulsed magnet for use at a free electron laser has been developed. This has a rise time of 10 microseconds and enables magneto-optical experiments in a parameter range previously inaccessible to condensed matter physicists. The joint of superconducting cables can be modelled by means of distributed circuit elements that characterise current diffusion.

  16. Rocket Tablet,

    Science.gov (United States)

    1984-09-12

    is a vast and desolate world, this is a strip of mir- aculous land! How many struggling dramas full of power and * grandeur were cheered, resisted and...rocket officers and men, a group enormous and powerful , marched into this land soaked with the fresh blood of our ancestors. This place is about to...and tough pestering said he wanted an American aircraft ob- tained on the battlefield to transport goods from Lanzhou, Xian, Beijing, Guangzhou and

  17. High-performance TDM demultiplexing of coherent Nyquist pulses using time-domain orthogonality.

    Science.gov (United States)

    Harako, Koudai; Otuya, David Odeke; Kasai, Keisuke; Hirooka, Toshihiko; Nakazawa, Masataka

    2014-12-01

    We propose a simple and high-performance scheme for demultiplexing coherent Nyquist TDM signals by photo-mixing on a photo-detector with Nyquist LO pulses. This scheme takes advantage of the time-domain orthogonality of Nyquist pulses, which enables high-SNR demultiplexing and homodyne detection simultaneously in spite of a strong overlap with adjacent pulses in the time domain. The feasibility of this scheme is demonstrated through a demultiplexing experiment employing 80 Gbaud, 64 QAM Nyquist pulse OTDM signals. This scheme exhibits excellent demultiplexing performance with a much simpler configuration than a conventional ultrafast all-optical sampling scheme.

  18. Performance of Several Conical Convergent-Divergent Rocket-Type Exhaust Nozzles

    Science.gov (United States)

    Campbell, C. E.; Farley, J. M.

    1960-01-01

    An investigation was conducted to obtain nozzle performance data with relatively large-scale models at pressure ratios as high as 120. Conical convergent-divergent nozzles with divergence angles alpha of 15, 25, and 29 deg. were each tested at area ratios of approximately 10, 25, and 40. Heated air (1200 F) was supplied at the nozzle inlet at pressures up to 145 pounds per square inch absolute and was exhausted into quiescent air at pressures as low as 1.2 pounds per square inch absolute. Thrust ratios for all nozzle configurations are presented over the range of pressure ratios attainable and were extrapolated when possible to design pressure ratio and beyond. Design thrust ratios decreased with increasing nozzle divergence angle according to the trend predicted by the (1 + cos alpha)/2 parameter. Decreasing the nozzle divergence angle resulted in sizable increases in thrust ratio for a given surface-area ratio (nozzle weight), particularly at low nozzle pressure ratios. Correlations of the nozzle static pressure at separation and of the average static pressure downstream of separation with various nozzle parameters permitted the calculation of thrust in the separated-flow region from unseparated static-pressure distributions. Thrust ratios calculated by this method agreed with measured values within about 1 percent.

  19. Performance of a UTC FW-4S solid propellant rocket motor under the command effects of simulated altitude and rotational spin

    Science.gov (United States)

    Merryman, H. L.; Smith, L. R.

    1974-01-01

    One United Technology Center FW-4S solid-propellant rocket motor was fired at an average simulated altitude of 103,000 ft while spinning about its axial centerline at 180 rpm. The objectives of the test program were to determine motor altitude ballistic performance including the measurement of the nonaxial thrust vector and to demonstrate structural integrity of the motor case and nozzle. These objectives are presented and discussed.

  20. Performance of a solenoid-driven pulsed molecular-beam source

    OpenAIRE

    Abad, Luis; Bermejo, Dionisio; Herrero, Víctor J.; Santos, J.; Tanarro, Isabel

    1995-01-01

    The characteristics of a commonly used pulsed valve for the production of free jets and molecular beams are analyzed in detail. Special attention is paid to the formation of gas pulses providing a quasisteady flow during a certain time interval within the pulse duration, and to the estimation of a scaling parameter (effective diameter) for the description of the flow field. The adequacy of this effective diameter is checked by performing time-of-flight measurements on molecular beams of Ne, N...

  1. Performance comparison of pulse-pair and wavelets methods for the pulse Doppler weather radar spectrum

    CERN Document Server

    Lagha, Mohand; Bergheul, Said; Rezoug, Tahar; Bettayeb, Maamar

    2012-01-01

    In the civilian aviation field, the radar detection of hazardous weather phenomena (winds) is very important. This detection will allow the avoidance of these phenomena and consequently will enhance the safety of flights. In this work, we have used the wavelets method to estimate the mean velocity of winds. The results showed that the application of this method is promising compared with the classical estimators (pulse-pair, Fourier).

  2. Pulsed laser propulsion performance of 11-cm parabolic bell engines within the atmosphere

    Science.gov (United States)

    Myrabo, Leik N.; Libeau, M. A.; Meloney, E. D.; Bracken, R. L.; Knowles, T. B.

    2004-09-01

    The paper presents pulsed laser propulsion performance data for three 11-cm diameter aluminum parabolic (or "bell-shaped") engines, tested with the 10-kW PLVTS pulsed CO2 laser at White Sands Missile Range, NM. The single-pulse and multiple-pulse tests were conducted on two campaigns, Sept. 2000 and Sept. 2001, using a ballistic pendulum apparatus. The results from two different sets of PLVTS resonator optics were gathered (both 2X and 3X magnification). Assuming the vertex is set at the parabola's focus (i.e., and viewing outward towards the 11-cm exit plane), the bell engines had three different total included angles of 60, 87.2, and 120 degrees. As expected, the impulse and coupling coefficient performance of the 60 deg. bell generally exceeded that of the 87.2 deg. engine, which in turn outperformed the 120 deg. bell. The maximum single-pulse coupling coefficients varied from 275 to 375 N-sec/MJ. Multiple-pulse engine performance data was also gathered with the same ballistic pendulum in the first campaign. A sequence of from 2 to 8 pulses was transmitted into each bell at a pulse repetition frequency of 25 HZ -- all delivered within the first 1/8th cycle of the pendulum's swing. In general, only small variations in the coupling coefficient were observed throughout the string of pulses.

  3. Impact of pulse duration on Ho:YAG laser lithotripsy: fragmentation and dusting performance.

    Science.gov (United States)

    Bader, Markus J; Pongratz, Thomas; Khoder, Wael; Stief, Christian G; Herrmann, Thomas; Nagele, Udo; Sroka, Ronald

    2015-04-01

    In vitro investigations of Ho:YAG laser-induced stone fragmentation were performed to identify potential impacts of different pulse durations on stone fragmentation characteristics. A Ho:YAG laser system (Swiss LaserClast, EMS S.A., Nyon, Switzerland) with selectable long or short pulse mode was tested with regard to its fragmentation and laser hardware compatibility properties. The pulse duration is depending on the specific laser parameters. Fragmentation tests (hand-held, hands-free, single-pulse-induced crater) on artificial BEGO stones were performed under reproducible experimental conditions (fibre sizes: 365 and 200 µm; laser settings: 10 W through combinations of 0.5, 1, 2 J/pulse and 20, 10, 5 Hz, respectively). Differences in fragmentation rates between the two pulse duration regimes were detected with statistical significance for defined settings. Hand-held and motivated Ho:YAG laser-assisted fragmentation of BEGO stones showed no significant difference between short pulse mode and long pulse mode, neither in fragmentation rates nor in number of fragments and fragment sizes. Similarly, the results of the hands-free fragmentation tests (with and without anti-repulsion device) showed no statistical differences between long pulse and short pulse modes. The study showed that fragmentation rates for long and short pulse durations at identical power settings remain at a comparable level. Longer holmium laser pulse duration reduces stone pushback. Therefore, longer laser pulses may result in better clinical outcome of laser lithotripsy and more convenient handling during clinical use without compromising fragmentation effectiveness.

  4. A chirped-pulse Fourier-transform microwave/pulsed uniform flow spectrometer. II. Performance and applications for reaction dynamics.

    Science.gov (United States)

    Abeysekera, Chamara; Zack, Lindsay N; Park, G Barratt; Joalland, Baptiste; Oldham, James M; Prozument, Kirill; Ariyasingha, Nuwandi M; Sims, Ian R; Field, Robert W; Suits, Arthur G

    2014-12-01

    This second paper in a series of two reports on the performance of a new instrument for studying chemical reaction dynamics and kinetics at low temperatures. Our approach employs chirped-pulse Fourier-transform microwave (CP-FTMW) spectroscopy to probe photolysis and bimolecular reaction products that are thermalized in pulsed uniform flows. Here we detail the development and testing of a new K(a)-band CP-FTMW spectrometer in combination with the pulsed flow system described in Paper I [J. M. Oldham, C. Abeysekera, B. Joalland, L. N. Zack, K. Prozument, I. R. Sims, G. B. Park, R. W. Field, and A. G. Suits, J. Chem. Phys. 141, 154202 (2014)]. This combination delivers broadband spectra with MHz resolution and allows monitoring, on the μs timescale, of the appearance of transient reaction products. Two benchmark reactive systems are used to illustrate and characterize the performance of this new apparatus: the photodissociation of SO2 at 193 nm, for which the vibrational populations of the SO product are monitored, and the reaction between CN and C2H2, for which the HCCCN product is detected in its vibrational ground state. The results show that the combination of these two well-matched techniques, which we refer to as chirped-pulse in uniform flow, also provides insight into the vibrational and rotational relaxation kinetics of the nascent reaction products. Future directions are discussed, with an emphasis on exploring the low temperature chemistry of complex polyatomic systems.

  5. Optimization Performance of a CO[subscript 2] Pulsed Tuneable Laser

    Science.gov (United States)

    Ribeiro, J. H. F.; Lobo, R. F. M.

    2009-01-01

    In this paper, a procedure is presented that will allow (i) the power and (ii) the energy of a pulsed and tuneable TEA CO[subscript 2] laser to be optimized. This type of laser represents a significant improvement in performance and portability. Combining a pulse mode with a grating tuning facility, it enables us to scan the working wavelength…

  6. Performance Limits of Pulse Tube Cryocoolers Using 3HE

    Science.gov (United States)

    Kittel, P.

    2008-03-01

    The enthalpy, entropy, and exergy flows resulting from the real gas effects of 3He in ideal pulse tube cryocoolers are described. The discussion follows a previous description of the real gas effects of 4He in ideal pulse tube cryocoolers and makes use of a recently developed model of the thermophysical properties of 3He. This model is used to describe how the thermodynamic flows are affected by real gas phenomena of 3He and compares these effects to similar effects for 4He. The analysis was done over the pressure range 0.3-2 MPa and temperatures down to 1 K. At 2 MPa there is almost no difference in the cooling power between 3He and 4He. At lower pressures, using 3He is advantageous. There is a 1-2 K reduction in the 3He cooling power vs. temperature curves compared to those for 4He in the 0.3-1 MPa range.

  7. Replacement of chemical rocket launchers by beamed energy propulsion.

    Science.gov (United States)

    Fukunari, Masafumi; Arnault, Anthony; Yamaguchi, Toshikazu; Komurasaki, Kimiya

    2014-11-01

    Microwave Rocket is a beamed energy propulsion system that is expected to reach space at drastically lower cost. This cost reduction is estimated by replacing the first-stage engine and solid rocket boosters of the Japanese H-IIB rocket with Microwave Rocket, using a recently developed thrust model in which thrust is generated through repetitively pulsed microwave detonation with a reed-valve air-breathing system. Results show that Microwave Rocket trajectory, in terms of velocity versus altitude, can be designed similarly to the current H-IIB first stage trajectory. Moreover, the payload ratio can be increased by 450%, resulting in launch-cost reduction of 74%.

  8. Hybrid Rocket Technology

    Directory of Open Access Journals (Sweden)

    Sankaran Venugopal

    2011-04-01

    Full Text Available With their unique operational characteristics, hybrid rockets can potentially provide safer, lower-cost avenues for spacecraft and missiles than the current solid propellant and liquid propellant systems. Classical hybrids can be throttled for thrust tailoring, perform in-flight motor shutdown and restart. In classical hybrids, the fuel is stored in the form of a solid grain, requiring only half the feed system hardware of liquid bipropellant engines. The commonly used fuels are benign, nontoxic, and not hazardous to store and transport. Solid fuel grains are not highly susceptible to cracks, imperfections, and environmental temperature and are therefore safer to manufacture, store, transport, and use for launch. The status of development based on the experience of the last few decades indicating the maturity of the hybrid rocket technology is given in brief.Defence Science Journal, 2011, 61(3, pp.193-200, DOI:http://dx.doi.org/10.14429/dsj.61.518

  9. 双脉冲固体发动机喷管传热烧蚀特性%Characterization of nozzle thermal and ablation response in dual-pulse solid rocket motors

    Institute of Scientific and Technical Information of China (English)

    张晓光; 刘宇; 王长辉

    2012-01-01

    In order to investigate the nozzle thermal and ablation characteristics in dual- pulse solid rocket motors, the transient value of the throat diameter was obtained from the pressure and thrust measurements. Furthermore, the in-depth thermal response, pyroly- sis/char profiles and surface recession of the nozzle assembly were predicted through fully coupled fluid-solid analysis using the commercial code FLUENT. Results show that during pulse operation, the insulation material pyrolysis/char profiles expand and the nozzle insert erosion rate increases. During pulse separation, heat conduction in the material leads to the decrease in the material temperature difference. The heat transfer and ablation processes of pulse 1 and pulse separation make the nozzle insert exhibit small heat sink, high surface temperature and large surface roughness, which would result in higher throat erosion rate when pulse 2 operates.%为了研究双脉冲固体发动机喷管的传热烧蚀特性,由燃烧室压强及发动机推力试验曲线得到了喷管喉径的瞬变值,由FLUENT流体计算软件进行流固耦合传热烧蚀计算,得到了喷管瞬态温度分布、绝热材料热解炭化情况及碳/碳(C/C)喉衬瞬态烧蚀率,分析了脉冲工作过程及脉冲间隔时间对喷管传热烧蚀的影响.计算结果表明,脉冲工作过程中,绝热材料热解线、炭化线向材料内部扩展,喉衬烧蚀率不断增大;脉冲间隔时间内,喷管材料内部的导热使各处温差减小,温度趋于一致;第一脉冲的传热烧蚀与脉冲间隔的材料导热使第二脉冲工作时喉衬整体热沉小、内壁初始温度高、表面粗糙度大,从而导致较高烧蚀率.

  10. Dual-Pulse Pulse Position Modulation (DPPM) for Deep-Space Optical Communications: Performance and Practicality Analysis

    Science.gov (United States)

    Li, Jing; Hylton, Alan; Budinger, James; Nappier, Jennifer; Downey, Joseph; Raible, Daniel

    2012-01-01

    Due to its simplicity and robustness against wavefront distortion, pulse position modulation (PPM) with photon counting detector has been seriously considered for long-haul optical wireless systems. This paper evaluates the dual-pulse case and compares it with the conventional single-pulse case. Analytical expressions for symbol error rate and bit error rate are first derived and numerically evaluated, for the strong, negative-exponential turbulent atmosphere; and bandwidth efficiency and throughput are subsequently assessed. It is shown that, under a set of practical constraints including pulse width and pulse repetition frequency (PRF), dual-pulse PPM enables a better channel utilization and hence a higher throughput than it single-pulse counterpart. This result is new and different from the previous idealistic studies that showed multi-pulse PPM provided no essential information-theoretic gains than single-pulse PPM.

  11. RAPID COMMUNICATION: Enhanced performance of a dielectric barrier discharge lamp using short-pulsed excitation

    Science.gov (United States)

    Mildren, R. P.; Carman, R. J.

    2001-01-01

    We observe marked increases in the time-averaged intensity, peak intensity, efficiency and spectral purity of the VUV output from an Xe excimer barrier discharge lamp when using short-pulse (~150 ns FWHM (full width half maximum)) excitation. Intensity increases with Xe pressure up to 600 Torr with a maximum output 2.6 times higher and an efficiency 3.2 times higher than the same lamp excited by conventional ac excitation (i.e. sinusoidal voltage waveform). The output occurs in regular short pulses (pulsed discharge appears diffuse (i.e. glow-like), even at the higher pressures at which the ac discharge is filamentary. It is concluded that the enhanced performance results largely from the ability for pulsed excitation to generate a discharge at near atmospheric pressures with a much lower electron density than that possible using ac.

  12. Pulsed Laser Propulsion Performance of 11-cm Parabolic `Bell' Engines: CO2 TEA vs. EDL

    Science.gov (United States)

    Mori, Koichi; Sasoh, Akihiro; Myrabo, Leik N.

    2006-05-01

    Single pulse laboratory experiments were carried out with a high-power CO2 Transversely-Excited Atmospheric (TEA) laser using three laser pulsejet engines, shaped as parabolic bells, measuring 11-cm in diameter. Assuming the vertex is set at the parabola's focus, the "calibration bell" engines had three different total divergence angles of 60, 87.2, and 120 degrees (i.e., viewing outward towards the 11-cm nozzle exit plane). The objective was to quantify and calibrate the effects of laser pulse duration upon the momentum coupling coefficient (Cm) performance from the two CO2 lasers, using laser pulse energy as the parametric variable. Bell engine performance data from the TEA laser are contrasted with former results from the PLVTS CO2 electron discharge laser (EDL). The single-pulse PLVTS tests were conducted in Sept. 2000 and Sept. 2001, revealing that the impulse and Cm performance of the 60° bell generally exceeded the 87.2° engine, which in turn outperformed the 120° bell. With PLVTS, the maximum single-pulse Cm varied from 275 to 375 N-sec/MJ. In contrast, the 2 microsecond TEA laser tests generated results that were distinctively different from that of the EDL. Both tests used a standard ballistic pendulum to measure airbreathing engine performance at a pressure of one atmosphere.

  13. Preliminary experimental investigation on pulse detonation rocket engine with central cone configuration%中心锥体结构脉冲爆震火箭发动机初步实验

    Institute of Scientific and Technical Information of China (English)

    严宇; 范玮; 王可; 穆杨

    2011-01-01

    In order to improve the atomization of liquid fuel and mixing of reactants in side the pulse detonation rocket engine using liquid fuel, a pulse detonation rocket engine with a different configuration was invented. A central cone instead of Shchelkin spiral was used in this engine. Reactants could be injected into the engine both through the engine head and the central cone. With kerosene used as fuel, oxygen as oxidizer and nitrogen as purge gas, fully developed detonation waves were generated in this engine, which could operate steadily on multi cycle mode. The result also indicates that this engine could greatly shorten the DDT (deflagration to detonation transition) run-up distance, and the DDT ruwup distance is approximately five times of the inner diameter of detonation tube. Compared with the approach of installing Shchelkin spiral in the detonation tube as DDT enhancement de vice, the DDT run-up distance of this engine was shortened by 57.5%.%为了改善采用液态燃料的脉冲爆震火箭发动机内部燃料的雾化以及燃料混合物的掺混状况,采用了一种中心锥体结构.该结构发动机不采用Shchelkin螺旋增爆装置,而采用中心锥体结构、二级供应方式.采用航空煤油为燃料、压缩氧气为氧化剂、压缩氮气为隔离气体,在该结构脉冲爆震火箭发动机上获得了充分发展的爆震波并且能够在多循环条件下稳定工作.实验结果表明,该结构可以大大缩短DDT(deflagra-tion to detonation transition)距离,在实验条件下爆燃向爆震转变距离约为管径的5倍.较之同一管径采用Shchelkin螺旋增爆装置的脉冲爆震火箭发动机,该结构发动机的爆燃向爆震转变距离缩短了57.5%.

  14. Rocket propulsion elements

    CERN Document Server

    Sutton, George P

    2011-01-01

    The definitive text on rocket propulsion-now revised to reflect advancements in the field For sixty years, Sutton's Rocket Propulsion Elements has been regarded as the single most authoritative sourcebook on rocket propulsion technology. As with the previous edition, coauthored with Oscar Biblarz, the Eighth Edition of Rocket Propulsion Elements offers a thorough introduction to basic principles of rocket propulsion for guided missiles, space flight, or satellite flight. It describes the physical mechanisms and designs for various types of rockets' and provides an unders

  15. The four INTA-300 rocket prototypes

    Science.gov (United States)

    Calero, J. S.

    1985-03-01

    A development history and performance capability assessment is presented for the INTA-300 'Flamenco' sounding rocket prototype specimens. The Flamenco is a two-stage solid fuel rocket, based on British sounding rocket technology, that can lift 50 km payloads to altitudes of about 300 km. The flight of the first two prototypes, in 1974 and 1975, pointed to vibration problems which reduced the achievable apogee, and the third prototype's flight was marred by a premature detonation that destroyed the rocket. The fourth Flamenco flight, however, yielded much reliable data.

  16. PERFORMANCE STUDIES OF CDZNTE DETECTOR BY USING A PULSE SHAPE ANALYSIS.

    Energy Technology Data Exchange (ETDEWEB)

    BOLOTNIKOV, A.

    2005-07-31

    Pulse shape analysis is proved to be a powerful tool to characterize the performance of CdZnTe devices and understand their operating principles. It allows one to investigate the device configurations, electron transport properties, effects governing charge collection, electric-field distributions, signal charge formation, etc. This work describes an application of different techniques based on the pulse shape measurements to characterize pixel, coplanar-grid, and virtual Frisch-grid devices and understand the electronic properties of CZT material provided by different vendors. We report new results that may explain the performance limits of these devices.

  17. Hydrocarbon Rocket Engine Plume Imaging with Laser Induced Incandescence Project

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA/ Marshall Space Flight Center (MSFC) needs sensors that can be operated on rocket engine plume environments to improve NASA/SSC rocket engine performance. In...

  18. Design and performance analysis of transmission line-based nanosecond pulse multiplier

    Indian Academy of Sciences (India)

    Rishi Verma; A Shyam; Kunal G Shah

    2006-10-01

    Conventionally, Marx generators are used for the production of short duration, high voltage pulses but since many discharge gap switches are utilized for stepping up the voltage, there are many disadvantages. Here, an alternative and much simpler technique for the multiplication of nanosecond high voltage pulses has been presented in which multiplication takes place by switching single spark gap providing voltage gain of $‘nxV’$ where is the subsequent number of stages. Stepped up high voltage pulse with fixed voltage gain of defined shape with fast rise time and good flat top is produced without using additional pulse-forming network. Its operation has been made repetitive by switching single spark gap. Multipurpose use, low cost, small size, light weight (weighing less than 50 kg) and portability are the additional benefits of the system. The reported nanosecond pulser has been made by cascading three stages of Blumlein. To cross check its performance the parasitic impedance of the system has been evaluated to realize its adverse effect on the voltage gain and pulse shape. Also its operation has been simulated by PSPICE circuit simulator program and good agreement has been obtained between simulated and experimental results. Applications of this pulse generator include X-ray generation, breakdown tests, ion implantation, streamer discharge studies and ultra wideband generation, among others.

  19. Solar Thermal Rocket Propulsion

    Science.gov (United States)

    Sercel, J. C.

    1986-01-01

    Paper analyzes potential of solar thermal rockets as means of propulsion for planetary spacecraft. Solar thermal rocket uses concentrated Sunlight to heat working fluid expelled through nozzle to produce thrust.

  20. Intelligent pulse light source in the performance calibration system of two-dimensional neutron detector

    Science.gov (United States)

    Yang, Lei; Zhao, Xiao-Fang

    2017-07-01

    Chinese Spallation Neutron Source (CSNS) project will use numerous two-dimensional (2D) neutron detectors whose ZnS (Ag) scintillator is doped with 6Li. To ensure the consistency of all neutron detectors, a calibration system for the performance of 2D neutron detectors is designed. For radiation protection, the state control of the radiation source gets more and more strict. It is impossible to directly carry out experiments with massive radioactive particles. Thus, the following scheme has been designed. The controlled pulsed laser light source on a 2D mobile platform is used to replace the neutron bombardment to generate the photon. The pulse signal drives the laser diode to generate pulse light. The pulse light source located on the 2D platform is controlled by the core controller, and goes to the wavelength shift fiber through the optical fiber. The host computer (PC) receives the signal from the electronics system, processes data, and automatically calibrates the performance parameters. As shown by the experimental results, the pulse light source can perfectly meet all requirements of 2D neutron detector calibration system.

  1. Comparison of Three Different Types of Wrist Pulse Signals by Their Physical Meanings and Diagnosis Performance.

    Science.gov (United States)

    Zuo, Wangmeng; Wang, Peng; Zhang, David

    2016-01-01

    Increasing interest has been focused on computational pulse diagnosis where sensors are developed to acquire pulse signals, and machine learning techniques are exploited to analyze health conditions based on the acquired pulse signals. By far, a number of sensors have been employed for pulse signal acquisition, which can be grouped into three major categories, i.e., pressure, photoelectric, and ultrasonic sensors. To guide the sensor selection for computational pulse diagnosis, in this paper, we analyze the physical meanings and sensitivities of signals acquired by these three types of sensors. The dependence and complementarity of the different sensors are discussed from both the perspective of cardiovascular fluid dynamics and comparative experiments by evaluating disease classification performance. Experimental results indicate that each sensor is more appropriate for the diagnosis of some specific disease that the changes of physiological factors can be effectively reflected by the sensor, e.g., ultrasonic sensor for diabetes and pressure sensor for arteriosclerosis, and improved diagnosis performance can be obtained by combining three types of signals.

  2. Design and Performance of a Novel Pancake Rogowski Coil for Measuring Pulse Currents%Design and Performance of a Novel Pancake Rogowski Coil for Measuring Pulse Currents

    Institute of Scientific and Technical Information of China (English)

    王春杰; 汲胜昌; 聂济宇; 欧小波; 韩钟健; 张乔根

    2011-01-01

    A novel pancake Rogowski coil without magnetic core is introduced in this paper. Owing to its special pancake winding structure, the coil is of low self-resistance and high self-inductance, and thus has excellent low frequency characteristic in the self-integral mode. Moreover, because of its unique installation method, the coil has a flexible sensitivity and can be applied under situations where toroidal air-core Rogowski coils or printed aircuit board (PCB) coils are not available. The parameters and performance of the pancake Rogowski coil are presented, and the principle of shielding is given. Measurements of step pulse current and oscillating pulse current by the coil are studied experimentally to illustrate its good linearity, reliable and flexible sensitivity and excellent frequency characteristic, especially its advantage in low frequency characteristic. The pancake Rogowski coil can be designed to assume round, square or rectangle shape, and has thus broad prospects in its application to the current measurement in such areas as plasma physics and pulsed power technology.

  3. Performance Evaluation of New-Generation Pulse Oximeters in the NICU: Observational Study.

    Science.gov (United States)

    Nizami, Shermeen; Greenwood, Kim; Barrowman, Nick; Harrold, JoAnn

    2015-09-01

    This crossover observational study compares the data characteristics and performance of new-generation Nellcor OXIMAX and Masimo SET SmartPod pulse oximeter technologies. The study was conducted independent of either original equipment manufacturer (OEM) across eleven preterm infants in a Neonatal Intensive Care Unit (NICU). The SmartPods were integrated with Dräger Infinity Delta monitors. The Delta monitor measured the heart rate (HR) using an independent electrocardiogram sensor, and the two SmartPods collected arterial oxygen saturation (SpO2) and pulse rate (PR). All patient data were non-Gaussian. Nellcor PR showed a higher correlation with the HR as compared to Masimo PR. The statistically significant difference found in their median values (1% for SpO2, 1 bpm for PR) was deemed clinically insignificant. SpO2 alarms generated by both SmartPods were observed and categorized for performance evaluation. Results for sensitivity, positive predictive value, accuracy and false alarm rates were Nellcor (80.3, 50, 44.5, 50%) and Masimo (72.2, 48.2, 40.6, 51.8%) respectively. These metrics were not statistically significantly different between the two pulse oximeters. Despite claims by OEMs, both pulse oximeters exhibited high false alarm rates, with no statistically or clinically significant difference in performance. These findings have a direct impact on alarm fatigue in the NICU. Performance evaluation studies can also impact medical device purchase decisions made by hospital administrators.

  4. Cramer-Rao Bounds and Coherence Performance Analysis for Next Generation Radar with Pulse Trains

    Directory of Open Access Journals (Sweden)

    Ning Zhang

    2013-04-01

    Full Text Available We study the Cramer-Rao bounds of parameter estimation and coherence performance for the next generation radar (NGR. In order to enhance the performance of NGR, the signal model of NGR with master-slave architecture based on a single pulse is extended to the case of pulse trains, in which multiple pulses are emitted from all sensors and then integrated spatially and temporally in a unique master sensor. For the MIMO mode of NGR where orthogonal waveforms are emitted, we derive the closed-form Cramer-Rao bound (CRB for the estimates of generalized coherence parameters (GCPs, including the time delay differences, total phase differences and Doppler frequencies with respect to different sensors. For the coherent mode of NGR where the coherent waveforms are emitted after pre-compensation using the estimates of GCPs, we develop a performance bound of signal-to-noise ratio (SNR gain for NGR based on the aforementioned CRBs, taking all the estimation errors into consideration. It is shown that greatly improved estimation accuracy and coherence performance can be obtained with pulse trains employed in NGR. Numerical examples demonstrate the validity of the theoretical results.

  5. Propellant Vaporization as a Criterion for Rocket-Engine Design; Experimental Performance, Vaporization and Heat-Transfer Rates with Various Propellant Combinations

    Science.gov (United States)

    Clark, Bruce J.; Hersch, Martin; Priem, Richard J.

    1959-01-01

    Experimental combustion efficiencies of eleven propellant combinations were determined as a function of chamber length. Efficiencies were measured in terms of characteristic exhaust velocities at three chamber lengths and in terms of gas velocities. The data were obtained in a nominal 200-pound-thrust rocket engine. Injector and engine configurations were kept essentially the same to allow comparison of the performance. The data, except for those on hydrazine and ammonia-fluorine, agreed with predicted results based on the assumption that vaporization of the propellants determines the rate of combustion. Decomposition in the liquid phase may be.responsible for the anomalous behavior of hydrazine. Over-all heat-transfer rates were also measured for each combination. These rates were close to the values predicted by standard heat-transfer calculations except for the combinations using ammonia.

  6. Mars Rocket Propulsion System

    Science.gov (United States)

    Zubrin, Robert; Harber, Dan; Nabors, Sammy

    2008-01-01

    A report discusses the methane and carbon monoxide/LOX (McLOx) rocket for ascent from Mars as well as other critical space propulsion tasks. The system offers a specific impulse over 370 s roughly 50 s higher than existing space-storable bio-propellants. Current Mars in-situ propellant production (ISPP) technologies produce impure methane and carbon monoxide in various combinations. While separation and purification of methane fuel is possible, it adds complexity to the propellant production process and discards an otherwise useful fuel product. The McLOx makes such complex and wasteful processes unnecessary by burning the methane/CO mixtures produced by the Mars ISPP systems without the need for further refinement. Despite the decrease in rocket-specific impulse caused by the CO admixture, the improvement offered by concomitant increased propellant density can provide a net improvement in stage performance. One advantage is the increase of the total amount of propellant produced, but with a decrease in mass and complexity of the required ISPP plant. Methane/CO fuel mixtures also may be produced by reprocessing the organic wastes of a Moon base or a space station, making McLOx engines key for a human Lunar initiative or the International Space Station (ISS) program. Because McLOx propellant components store at a common temperature, very lightweight and compact common bulkhead tanks can be employed, improving overall stage performance further.

  7. Manufacturing technology effect on current pulse handling performance of metallized polypropylene film capacitors

    Science.gov (United States)

    El-Husseini, M. H.; Venet, P.; Al-Majid, A.; Fathallah, M.; Rojat, G.; Ferreira, J. A.

    2003-09-01

    In this paper, the testing of the pulse-withstanding capability of metallized polypropylene film (MPPF) capacitors is reported. Four groups of capacitors having the same electrical characteristics but different geometry were considered for the test. Capacitors with long geometry seem to have poorer pulse handling performance for similar electrical stress conditions. However, the premature failure of one of the capacitor groups tested suggests that the quality of the end-edge contact is strongly dependent on the physical features of the manufacturing process. The end-edge contact plays a vital role in the current pulse handling capability of MPPF capacitors, which varies from a few hundred to several thousand discharging cycles depending on the geometry of the capacitor and the end-edge contact manufacturing process.

  8. Optimizing the performance of TOAD by changing the wavelength and power of control pulse

    Institute of Scientific and Technical Information of China (English)

    Liangsheng Wen(温亮生); Peng Zuo(左鹏); Jian Wu(伍剑); Jintong Lin(林金桐)

    2003-01-01

    The performance of terahertz optical asymmetric demultiplexer (TOAD) has been studied by modelling the semiconductor optical amplifier (SOA) in which the intraband effects had been taken into account.Numerical results are coincident with the experiment results. We interpret why there are three peaks in the switching window, which has never been reported before. In addition, we put forward the definition of the flatness of the switching window of TOAD for the first time By analysing the different phase of clockwise and counter clockwise signal pulse changed by SOA, appropriate peak power of control pulse and wavelength of signal and control pulse have been calculated in order to obtain large output power and flat switching window of TOAD.

  9. Rockets two classic papers

    CERN Document Server

    Goddard, Robert

    2002-01-01

    Rockets, in the primitive form of fireworks, have existed since the Chinese invented them around the thirteenth century. But it was the work of American Robert Hutchings Goddard (1882-1945) and his development of liquid-fueled rockets that first produced a controlled rocket flight. Fascinated by rocketry since boyhood, Goddard designed, built, and launched the world's first liquid-fueled rocket in 1926. Ridiculed by the press for suggesting that rockets could be flown to the moon, he continued his experiments, supported partly by the Smithsonian Institution and defended by Charles Lindbergh. T

  10. Differential linear scan voltammetry: analytical performance in comparison with pulsed voltammetry techniques.

    Science.gov (United States)

    Sheth, Disha B; Gratzl, Miklós

    2013-06-01

    We report here on differential linear scan voltammetry, DLSV, that combines the working principles of linear scan voltammetry, LSV, and the numerous existing pulsed voltammetry techniques. DLSV preserves the information from continuous interrogation in voltage and high accuracy that LSV provides about electrochemical processes, and the much better sensitivity of differential pulsed techniques. DLSV also minimizes the background current compared to both LSV and pulsed voltammetry. An early version of DLSV, derivative stationary electrode polarography, DSEP, had been proposed in the 1960s but soon abandoned in favor of the emerging differential pulsed techniques. Relative to DSEP, DLSV takes advantage of the flexibility of discrete smoothing differentiation that was not available to early investigators. Also, DSEP had been explored in pure solutions and with reversible electrochemical reactions. DLSV is tested in this work in more challenging experimental contexts: the measurement of oxygen with a carbon fiber microelectrode in buffer, and with a gold microdisc electrode exposed to a live biological preparation. This work compares the analytical performance of DLSV and square wave voltammetry, the most popular pulsed voltammetry technique.

  11. Aerodynamics and flow characterisation of multistage rockets

    Science.gov (United States)

    Srinivas, G.; Prakash, M. V. S.

    2017-05-01

    The main objective of this paper is to conduct a systematic flow analysis on single, double and multistage rockets using ANSYS software. Today non-air breathing propulsion is increasing dramatically for the enhancement of space exploration. The rocket propulsion is playing vital role in carrying the payload to the destination. Day to day rocket aerodynamic performance and flow characterization analysis has becoming challenging task to the researchers. Taking this task as motivation a systematic literature is conducted to achieve better aerodynamic and flow characterization on various rocket models. The analyses on rocket models are very little especially in numerical side and experimental area. Each rocket stage analysis conducted for different Mach numbers and having different flow varying angle of attacks for finding the critical efficiency performance parameters like pressure, density and velocity. After successful completion of the analysis the research reveals that flow around the rocket body for Mach number 4 and 5 best suitable for designed payload. Another major objective of this paper is to bring best aerodynamics flow characterizations in both aero and mechanical features. This paper also brings feature prospectus of rocket stage technology in the field of aerodynamic design.

  12. Influence of the Water-Cooled Heat Exchanger on the Performance of a Pulse Tube Refrigerator

    Directory of Open Access Journals (Sweden)

    Wei Wang

    2017-02-01

    Full Text Available The water-cooled heat exchanger is one of the key components in a pulse tube refrigerator. Its heat exchange effectiveness directly influences the cooling performance of the refrigerator. However, effective heat exchange does not always result in a good performance, because excessively reinforced heat exchange can lead to additional flow loss. In this paper, seven different water-cooled heat exchangers were designed to explore the best configuration for a large-capacity pulse tube refrigerator. Results indicated that the heat exchanger invented by Hu always offered a better performance than that of finned and traditional shell-tube types. For a refrigerator with a working frequency of 50 Hz, the best hydraulic diameter is less than 1 mm.

  13. Pulsed-mode operation and performance of a ferromagnetic shape memory alloy actuator

    Science.gov (United States)

    Asua, E.; García-Arribas, A.; Etxebarria, V.; Feuchtwanger, J.

    2014-02-01

    The actuation capabilities and positioning performance of a single crystal ferromagnetic shape memory alloy (FSMA) operated in pulsed mode are evaluated in a prototype device. It consists of two orthogonal coil pairs that produce the magnetic fields necessary for the non-contact deformation of the material. The position of the top of the crystal after actuation is measured by a capacitive sensor. A specifically designed power module drives the discharge of a set of capacitors through the coils, producing fast current pulses of large amplitudes (about 250 A), the coil pairs are driven independently to control the direction of actuation. Open-loop experiments demonstrate that successive pulses of increasing magnitude successfully produced the desired expansion and contraction of the crystal, depending on the pair of coils that is activated. The deformation achieved is maintained after the pulses, highlighting the advantageous set-and-forget operation of the device. Closed-loop experiments are performed using a double proportional-integral-derivative controller, designed to take advantage of the energy-saving quality of the set-and-forget operation. Despite the nonlinear response and hysteric response of FSMA materials, a reference position can be reached and maintained with a maximum error of 0.5 μm.

  14. Wave-shaping of pulse tube cryocooler components for improved performance

    Science.gov (United States)

    Antao, Dion Savio; Farouk, Bakhtier

    2014-11-01

    The method of wave-shaping acoustic resonators is applied to an inertance type cryogenic pulse tube refrigerator (IPTR) to improve its performance. A detailed time-dependent axisymmetric experimentally validated computational fluid dynamic (CFD) model of the PTR is used to predict its performance. The continuity, momentum and energy equations are solved for both the refrigerant gas (helium) and the porous media regions (the regenerator and the three heat-exchangers) in the PTR. An improved representation of heat transfer in the porous media is achieved by employing a thermal non-equilibrium model to couple the gas and solid (porous media) energy equations. The wave-shaped regenerator and pulse tube studied have cone geometries and the effects of different cone angles and the orientation (nozzle v/s diffuser mode) on the system performance are investigated. The resultant spatio-temporal pressure, temperature and velocity fields in the regenerator and pulse tube components are evaluated. The performance of these wave-shaped PTRs is compared to the performance of a non wave-shaped system with cylindrical components. Better cooling is predicted for the cryocooler using wave-shaped components oriented in the diffuser mode.

  15. Performance of the solid deuterium ultra-cold neutron source at the pulsed reactor TRIGA Mainz

    CERN Document Server

    Karch, J; Beck, M; Eberhardt, K; Hampel, G; Heil, W; Kieser, R; Reich, T; Trautmann, N; Ziegner, M

    2013-01-01

    The performance of the solid deuterium ultra-cold neutron source at the pulsed reactor TRIGA Mainz with a maximum peak energy of 10 MJ is described. The solid deuterium converter with a volume of V=160 cm3 (8 mol), which is exposed to a thermal neutron fluence of 4.5x10^13 n/cm2, delivers up to 550 000 UCN per pulse outside of the biological shield at the experimental area. UCN densities of ~ 10/cm3 are obtained in stainless steel bottles of V ~ 10 L resulting in a storage efficiency of ~20%. The measured UCN yields compare well with the predictions from a Monte Carlo simulation developed to model the source and to optimize its performance for the upcoming upgrade of the TRIGA Mainz into a user facility for UCN physics.

  16. Introduction to rocket science and engineering

    CERN Document Server

    Taylor, Travis S

    2009-01-01

    What Are Rockets? The History of RocketsRockets of the Modern EraRocket Anatomy and NomenclatureWhy Are Rockets Needed? Missions and PayloadsTrajectoriesOrbitsOrbit Changes and ManeuversBallistic Missile TrajectoriesHow Do Rockets Work? ThrustSpecific ImpulseWeight Flow RateTsiolkovsky's Rocket EquationStagingRocket Dynamics, Guidance, and ControlHow Do Rocket Engines Work? The Basic Rocket EngineThermodynamic Expansion and the Rocket NozzleExit VelocityRocket Engine Area Ratio and LengthsRocket Engine Design ExampleAre All Rockets the Same? Solid Rocket EnginesLiquid Propellant Rocket Engines

  17. Performance and Facility Background Pressure Characterization Tests of NASAs 12.5-kW Hall Effect Rocket with Magnetic Shielding Thruster

    Science.gov (United States)

    Kamhawi, Hani; Huang, Wensheng; Haag, Thomas; Shastry, Rohit; Thomas, Robert; Yim, John; Herman, Daniel; Williams, George; Myers, James; Hofer, Richard; Mikellides, Ioannis; Sekerak, Michael; Polk, James

    2015-01-01

    NASA's Space Technology Mission Directorate (STMD) Solar Electric Propulsion Technology Demonstration Mission (SEP/TDM) project is funding the development of a 12.5-kW Hall thruster system to support future NASA missions. The thruster designated Hall Effect Rocket with Magnetic Shielding (HERMeS) is a 12.5-kW Hall thruster with magnetic shielding incorporating a centrally mounted cathode. HERMeS was designed and modeled by a NASA GRC and JPL team and was fabricated and tested in vacuum facility 5 (VF5) at NASA GRC. Tests at NASA GRC were performed with the Technology Development Unit 1 (TDU1) thruster. TDU1's magnetic shielding topology was confirmed by measurement of anode potential and low electron temperature along the discharge chamber walls. Thermal characterization tests indicated that during full power thruster operation at peak magnetic field strength, the various thruster component temperatures were below prescribed maximum allowable limits. Performance characterization tests demonstrated the thruster's wide throttling range and found that the thruster can achieve a peak thruster efficiency of 63% at 12.5 kW 500 V and can attain a specific impulse of 3,000 s at 12.5 kW and a discharge voltage of 800 V. Facility background pressure variation tests revealed that the performance, operational characteristics, and magnetic shielding effectiveness of the TDU1 design were mostly insensitive to increases in background pressure.

  18. Performance characteristics of an excimer laser (XeCl) with single-stage magnetic pulse compression

    Science.gov (United States)

    Varshnay, N. K.; Singh, A.; Benerji, N. S.

    2017-02-01

    Performance characteristics of an excimer laser (XeCl) with single-stage magnetic pulse compression suitable for material processing applications are presented here. The laser incorporates in-built compact gas circulation and gas cooling to ensure fresh gas mixture between the electrodes for repetitive operation. A magnetically coupled tangential blower is used for gas circulation inside the laser chamber for repetitive operation. The exciter consists of C-C energy transfer circuit and thyratron is used as a high-voltage main switch with single-stage magnetic pulse compression (MPC) between thyratron and the laser electrodes. Low inductance of the laser head and uniform and intense pre-ionization are the main features of the electric circuit used in the laser. A 250 ns rise time voltage pulse was compressed to 100 ns duration with a single-stage magnetic pulse compressor using Ni-Zn ferrite cores. The laser can generate about 150 mJ at ˜100 Hz rep-rate reliably from a discharge volume of 100 cm 3. 2D spatial laser beam profile generated is presented here. The profile shows that the laser beam is completely filled with flat-top which is suitable for material processing applications. The SEM image of the microhole generated on copper target is presented here.

  19. Performance characteristics of an excimer laser (XeCl) with single-stage magnetic pulse compression

    Indian Academy of Sciences (India)

    N K VARSHNAY; A A SINGH; N S BENERJI

    2017-02-01

    Performance characteristics of an excimer laser (XeCl) with single-stage magnetic pulse compression suitable for material processing applications are presented here. The laser incorporates in-built compact gas circulation and gas cooling to ensure fresh gas mixture between the electrodes for repetitive operation. A magnetically coupled tangential blower is used for gas circulation inside the laser chamber for repetitive operation. The exciter consists of C–C energy transfer circuit and thyratron is used as a high-voltage main switch with singlestage magnetic pulse compression (MPC) between thyratron and the laser electrodes. Low inductance of the laser head and uniform and intense pre-ionization are the main features of the electric circuit used in the laser. A 250 ns rise time voltage pulse was compressed to 100 ns duration with a single-stage magnetic pulse compressor using Ni–Zn ferrite cores. The laser can generate about 150 mJ at ∼100 Hz rep-rate reliably from a discharge volumeof 100 cm$^3$. 2D spatial laser beam profile generated is presented here. The profile shows that the laser beam is completely filled with flat-top which is suitable for material processing applications. The SEM image of the microhole generated on copper target is presented here.

  20. The flight of uncontrolled rockets

    CERN Document Server

    Gantmakher, F R; Dryden, H L

    1964-01-01

    International Series of Monographs on Aeronautics and Astronautics, Division VII, Volume 5: The Flight of Uncontrolled Rockets focuses on external ballistics of uncontrolled rockets. The book first discusses the equations of motion of rockets. The rocket as a system of changing composition; application of solidification principle to rockets; rotational motion of rockets; and equations of motion of the center of mass of rockets are described. The text looks at the calculation of trajectory of rockets and the fundamentals of rocket dispersion. The selection further focuses on the dispersion of f

  1. Improved Performance of an Indigenous Stirling Type Pulse Tube Cooler and Pressure Wave Generator

    Science.gov (United States)

    Kumar, J. Kranthi; Jacob, S.; Karunanithi, R.; Narasimham, G. S. V. L.; Damu, C.; Praveen, T.; Samir, M.

    Sustained efforts have been made in our laboratory to improve the performance of an indigenously developed pressure wave gen- erator by reducing the mechanical losses and the required input power. An acoustically matching pulse tube cooler, with a design target of 0.5 W at 80 K, was designed using Sage and experience gained from previous studies. The pulse tube cooler was fabri- cated and tested. The effect of regenerator stacking pattern on the cooler performance was studied by filling the regenerator with mesh of the same size #400 and with multi meshes #250, 325, 400. In present experiments, regenerator with #400 mesh at 30 bar filling pressure performed better with more energy efficiency. A no load temperature of 74 K was achieved with input power of 59 W corresponding to a cooling power of 0.22 W at 80 K. Parasitic heat load to the cooler was measured be 0.68 W. This heat load is primarily by heat conduction through the regenerator and pulse tube wall. By reducing the wall thickness from 0.30 mm to 0.15 mm, the parasitic loads can be reduced by 50%.

  2. Hybrid Rocket Technology

    National Research Council Canada - National Science Library

    Sankaran Venugopal; K K Rajesh; V Ramanujachari

    2011-01-01

    With their unique operational characteristics, hybrid rockets can potentially provide safer, lower-cost avenues for spacecraft and missiles than the current solid propellant and liquid propellant systems...

  3. Performance of rocket cultivars under different nutritive solutions with salinity different. = Desempenho de cultivares de rúcula sob soluções nutritivas com diferentes salinidades.

    Directory of Open Access Journals (Sweden)

    Francisco de Assis de Oliveira

    2013-08-01

    Full Text Available The use of saline water for vegetable production is a major challenge for researchers and farmers. Cultivation in inert substrate can be an alternative, since the low matric potential can reduce the effect of salinity on plants. This study was conducted in a greenhouse at the Departamento de Ciências Ambientais e Tecnológicas da Universidade Federal Rural do Semi-Árido, Mossoró-RN, in order to evaluate the performance of two cultivars of rocket grown in substrate and fertilized with nutrient solutions of different salinities . Ten treatments were evaluated in a factorial 2 x 5, two cultivars (C1-Cultivada e C2-Folha Larga and five salinity levels of the nutrient solutions (S1-1.2; S2-2.2; S3-3.2; S4-4.2 and S5-5.2 dS m-1, usinga randomized design. Harvesting was performed at 30 days after sowing and evaluated the following variables: number of leaves, height, leaf area, total fresh and total dry mass. The salinity of the nutrient solution adversely affected the development of rocket, grown on a substrate, however, cultivation rocket substrate may be performed using electrical conductivity of the nutritive solution to 2.36 dS m-1 without loss in yield fresh pasta. The Folha Larga cultivar produced more total fresh and dry weight in relation to cultivar Cultivada, but to cultivar Cultivada has increased tolerance to salinity than cultivar Folha Larga. = O uso de água salina na produção de hortaliças é um dos principais desafios de pesquisadores e produtores rurais. O cultivo em substrato inerte pode ser uma alternativa, uma vez que o reduzido potencial matricial pode reduzir o efeito da salinidade sobre as plantas. O trabalho foi desenvolvido em ambiente protegido no Departamento de Ciências Ambientaise Tecnológicas da Universidade Federal Rural do Semi-Árido, Mossoró-RN, e objetivou-se avaliar o desempenho de duas cultivares de rúcula cultivadas em substrato e fertirrigadas com soluções nutritivas de diferentes salinidades. Foram

  4. Comparison of Computed and Measured Performance of a Pulsed Inductive Thruster Operating on Argon Propellant

    Science.gov (United States)

    Polzin, Kurt A.; Sankaran, Kameshwaran; Ritchie, Andrew G.; Peneau, Jarred P.

    2012-01-01

    Pulsed inductive plasma accelerators are electrodeless space propulsion devices where a capacitor is charged to an initial voltage and then discharged through a coil as a high-current pulse that inductively couples energy into the propellant. The field produced by this pulse ionizes the propellant, producing a plasma near the face of the coil. Once a plasma is formed if can be accelerated and expelled at a high exhaust velocity by the Lorentz force arising from the interaction of an induced plasma current and the magnetic field. A recent review of the developmental history of planar-geometry pulsed inductive thrusters, where the coil take the shape of a flat spiral, can be found in Ref. [1]. Two concepts that have employed this geometry are the Pulsed Inductive Thruster (PIT)[2, 3] and the Faraday Accelerator with Radio-frequency Assisted Discharge (FARAD)[4]. There exists a 1-D pulsed inductive acceleration model that employs a set of circuit equations coupled to a one-dimensional momentum equation. The model was originally developed and used by Lovberg and Dailey[2, 3] and has since been nondimensionalized and used by Polzin et al.[5, 6] to define a set of scaling parameters and gain general insight into their effect on thruster performance. The circuit presented in Fig. 1 provides a description of the electrical coupling between the current flowing in the thruster I1 and the plasma current I2. Recently, the model was upgraded to include an equation governing the deposition of energy into various modes present in a pulsed inductive thruster system (acceleration, magnetic flux generation, resistive heating, etc.)[7]. An MHD description of the plasma energy density evolution was tailored to the thruster geometry by assuming only one-dimensional motion and averaging the plasma properties over the spatial dimensions of the current sheet to obtain an equation for the time-evolution of the total energy. The equation set governing the dynamics of the coupled

  5. Optimization of Tape Winding Process Parameters to Enhance the Performance of Solid Rocket Nozzle Throat Back Up Liners using Taguchi's Robust Design Methodology

    Science.gov (United States)

    Nath, Nayani Kishore

    2016-06-01

    The throat back up liners is used to protect the nozzle structural members from the severe thermal environment in solid rocket nozzles. The throat back up liners is made with E-glass phenolic prepregs by tape winding process. The objective of this work is to demonstrate the optimization of process parameters of tape winding process to achieve better insulative resistance using Taguchi's robust design methodology. In this method four control factors machine speed, roller pressure, tape tension, tape temperature that were investigated for the tape winding process. The presented work was to study the cogency and acceptability of Taguchi's methodology in manufacturing of throat back up liners. The quality characteristic identified was Back wall temperature. Experiments carried out using L{9/'} (34) orthogonal array with three levels of four different control factors. The test results were analyzed using smaller the better criteria for Signal to Noise ratio in order to optimize the process. The experimental results were analyzed conformed and successfully used to achieve the minimum back wall temperature of the throat back up liners. The enhancement in performance of the throat back up liners was observed by carrying out the oxy-acetylene tests. The influence of back wall temperature on the performance of throat back up liners was verified by ground firing test.

  6. Performance assessment of different pulse reconstruction algorithms for the ATHENA X-ray Integral Field Unit

    Science.gov (United States)

    Peille, Philippe; Ceballos, Maria Teresa; Cobo, Beatriz; Wilms, Joern; Bandler, Simon; Smith, Stephen J.; Dauser, Thomas; Brand, Thorsten; den Hartog, Roland; de Plaa, Jelle; Barret, Didier; den Herder, Jan-Willem; Piro, Luigi; Barcons, Xavier; Pointecouteau, Etienne

    2016-07-01

    The X-ray Integral Field Unit (X-IFU) microcalorimeter, on-board Athena, with its focal plane comprising 3840 Transition Edge Sensors (TESs) operating at 90 mK, will provide unprecedented spectral-imaging capability in the 0.2-12 keV energy range. It will rely on the on-board digital processing of current pulses induced by the heat deposited in the TES absorber, as to recover the energy of each individual events. Assessing the capabilities of the pulse reconstruction is required to understand the overall scientific performance of the X-IFU, notably in terms of energy resolution degradation with both increasing energies and count rates. Using synthetic data streams generated by the X-IFU End-to-End simulator, we present here a comprehensive benchmark of various pulse reconstruction techniques, ranging from standard optimal filtering to more advanced algorithms based on noise covariance matrices. Beside deriving the spectral resolution achieved by the different algorithms, a first assessment of the computing power and ground calibration needs is presented. Overall, all methods show similar performances, with the reconstruction based on noise covariance matrices showing the best improvement with respect to the standard optimal filtering technique. Due to prohibitive calibration needs, this method might however not be applicable to the X-IFU and the best compromise currently appears to be the so-called resistance space analysis which also features very promising high count rate capabilities.

  7. Performance characteristics of an induction linac magnetic pulse compression modulator at multi-kilohertz pulse repetition frequencies

    Energy Technology Data Exchange (ETDEWEB)

    Sampayan, S.E.; Chambers, F.W.; Deadrick, F.J. [and others

    1991-05-01

    The ETA-II linear induction accelerator utilizes four pulse power conditioning chains. Magnetic pulse compression modulators (MAG1-Ds) form the last stage of each chain. A single power conditioning chain is used to drive the injector; the remaining three are used to drive 60 accelerator cells. Nominal parameters of the MAG1-D are an output voltage of greater than 120 kV, pulse width of 70 ns, and an output impedance of 2 ohms. Our operations goal for ETA-II is stable high average power operation at 5 kHz PRF. We have begun upgrading and characterizing the power conditioning chain on our High Average Power Test Stand (HAPTS). On HAPTS, the pulse to pulse amplitude stability has been improved to less than 0.7% (one sigma) and of order 3-5 ns random jitter about a systematic timing variation. In this paper we describe the status of our work to achieve the this paper we describe the status of our work to achieve the average power operation of ETA-II

  8. Hanford Tank Farms Waste Feed Flow Loop Phase VI: PulseEcho System Performance Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Denslow, Kayte M.; Bontha, Jagannadha R.; Adkins, Harold E.; Jenks, Jeromy WJ; Hopkins, Derek F.

    2012-11-21

    This document presents the visual and ultrasonic PulseEcho critical velocity test results obtained from the System Performance test campaign that was completed in September 2012 with the Remote Sampler Demonstration (RSD)/Waste Feed Flow Loop cold-test platform located at the Monarch test facility in Pasco, Washington. This report is intended to complement and accompany the report that will be developed by WRPS on the design of the System Performance simulant matrix, the analysis of the slurry test sample concentration and particle size distribution (PSD) data, and the design and construction of the RSD/Waste Feed Flow Loop cold-test platform.

  9. Effect of vitamin B-12 pulse addition on the performance of cobalt deprived anaerobic granular sludge bioreactors

    NARCIS (Netherlands)

    Fermoso, F.G.; Bartacek, J.; Lens, P.N.L.

    2010-01-01

    The effect of a pulse addition of vitamin B-12 as cobalt source to restore the performance of cobalt depleted methanol-fed bioreactors was investigated. One upflow anaerobic sludge bed (UASB) reactor was supplied with a pulse of vitamin B-12, and its operation was compared to that of another cobalt

  10. Effect of vitamin B-12 pulse addition on the performance of cobalt deprived anaerobic granular sludge bioreactors

    NARCIS (Netherlands)

    Fermoso, F.G.; Bartacek, J.; Lens, P.N.L.

    2010-01-01

    The effect of a pulse addition of vitamin B-12 as cobalt source to restore the performance of cobalt depleted methanol-fed bioreactors was investigated. One upflow anaerobic sludge bed (UASB) reactor was supplied with a pulse of vitamin B-12, and its operation was compared to that of another cobalt

  11. Specifics of Pulsed Arc Welding Power Supply Performance Based On A Transistor Switch

    Science.gov (United States)

    Krampit, N. Yu; Kust, T. S.; Krampit, M. A.

    2016-08-01

    Specifics of designing a pulsed arc welding power supply device are presented in the paper. Electronic components for managing large current was analyzed. Strengths and shortcomings of power supply circuits based on thyristor, bipolar transistor and MOSFET are outlined. As a base unit for pulsed arc welding was chosen MOSFET transistor, which is easy to manage. Measures to protect a transistor are given. As for the transistor control device is a microcontroller Arduino which has a low cost and adequate performance of the work. Bead transfer principle is to change the voltage on the arc in the formation of beads on the wire end. Microcontroller controls transistor when the arc voltage reaches the threshold voltage. Thus there is a separation and transfer of beads without splashing. Control strategies tested on a real device and presented. The error in the operation of the device is less than 25 us, it can be used controlling drop transfer at high frequencies (up to 1300 Hz).

  12. Space Launch System Base Heating Test: Sub-Scale Rocket Engine/Motor Design, Development & Performance Analysis

    Science.gov (United States)

    Mehta, Manish; Seaford, Mark; Kovarik, Brian; Dufrene, Aaron; Solly, Nathan

    2014-01-01

    ATA-002 Technical Team has successfully designed, developed, tested and assessed the SLS Pathfinder propulsion systems for the Main Base Heating Test Program. Major Outcomes of the Pathfinder Test Program: Reach 90% of full-scale chamber pressure Achieved all engine/motor design parameter requirements Reach steady plume flow behavior in less than 35 msec Steady chamber pressure for 60 to 100 msec during engine/motor operation Similar model engine/motor performance to full-scale SLS system Mitigated nozzle throat and combustor thermal erosion Test data shows good agreement with numerical prediction codes Next phase of the ATA-002 Test Program Design & development of the SLS OML for the Main Base Heating Test Tweak BSRM design to optimize performance Tweak CS-REM design to increase robustness MSFC Aerosciences and CUBRC have the capability to develop sub-scale propulsion systems to meet desired performance requirements for short-duration testing.

  13. Lidar Sensor Performance in Closed-Loop Flight Testing of the Morpheus Rocket-Propelled Lander to a Lunar-Like Hazard Field

    Science.gov (United States)

    Roback, V. Eric; Pierrottet, Diego F.; Amzajerdian, Farzin; Barnes, Bruce W.; Bulyshev, Alexander E.; Hines, Glenn D.; Petway, Larry B.; Brewster, Paul F.; Kempton, Kevin S.

    2015-01-01

    into the ALHAT navigation filter to provide lander guidance to the safe site. The flight tests served as the culmination of the TRL 6 journey for the ALHAT system and included launch from a pad situated at the NASA-Kennedy Space Center Shuttle Landing Facility (SLF) runway, a lunar-like descent trajectory from an altitude of 250m, and landing on a lunar-like hazard field of rocks, craters, hazardous slopes, and safe sites 400m down-range just off the North end of the runway. The tests both confirmed the expected performance and also revealed several challenges present in the flight-like environment which will feed into future TRL advancement of the sensors. Guidance provided by the ALHAT system was impeded in portions of the trajectory and intermittent near the end of the trajectory due to optical effects arising from air heated by the rocket engine. The Flash Lidar identified hazards as small as 30 cm from the maximum slant range of 450 m which Morpheus could provide; however, it was occasionally susceptible to an increase in range noise due to scintillation arising from air heated by the Morpheus rocket engine which entered its Field-of-View (FOV). The Flash Lidar was also susceptible to pre-triggering, during the HRN phase, on a dust cloud created during launch and transported down-range by the wind. The NDL provided velocity and range measurements to the expected accuracy levels yet it was also susceptible to signal degradation due to air heated by the rocket engine. The LA, operating with a degraded transmitter laser, also showed signal attenuation over a few seconds at a specific phase of the flight due to the heat plume generated by the rocket engine.

  14. The Ion Rocket

    Science.gov (United States)

    1961-05-29

    discharge velocity w and the speci- fic impulse lap respectively cannot be increased. At this limit condition the thermal rocket oecouos "choked up...structural quality is 900 t, 3) In the case of an atomic-driven thermal rocket ’,;lth specific Ipipulse ISjy«8C0 sec and thrust to weight ratio « 1, the

  15. Model Rockets and Microchips.

    Science.gov (United States)

    Fitzsimmons, Charles P.

    1986-01-01

    Points out the instructional applications and program possibilities of a unit on model rocketry. Describes the ways that microcomputers can assist in model rocket design and in problem calculations. Provides a descriptive listing of model rocket software for the Apple II microcomputer. (ML)

  16. Performance and Thrust-to-Weight Optimization of the Dual-Expander Aerospike Nozzle Upper Stage Rocket Engine

    Science.gov (United States)

    2012-06-01

    Copper (C17000 TH04) Oxygen-Free Copper (C10100 1180 Temper) Cobalt (Forged Electrolytic) INCONEL ® 718 (Annealed & Aged) Compatible with O2 / Useable... INCONEL 718 Copper Table 9 Impact of material strength on T/W Worst Material Selection Best Material Selection Yield Strength Ultimate...Copper Hydrogen Plumbing INCOLOY 909 Oxygen Plumbing INCONEL 718 American Institute of Aeronautics and Astronautics 24 The performance values for

  17. Performance Improvement of Pulse Tube Refrigerator for Space Application with Helium-hydrogen mixture

    Science.gov (United States)

    Chen, G. B.; Yu, J. P.; Gan, Z. H.

    Weight or size of the cryocoolers used is a key factor in space applications This can be acquired by the selection of high efficiency cryocoolers or through the optimization of structural parameters. Given the type of regenerator, another way to improve the cooling performance is the adoption of gas mixture instead of pure helium as the working fluids. Gas mixtures have been proved very useful to J-T cryocoolers at 80K temperature range. In this paper, we do some theoretical and experimental study to probe into the possibility of using gas mixture to improve the coefficient of performance of regenerative cryocoolers such as pulse tube refrigerators. The performance comparison of regenerator using helium-hydrogen mixtures to pure helium gas is presented based on the analysis of the heat transfer and fluid flow. The pressure drop for helium-hydrogen mixture decreased more rapidly than the increase of thermal loss compared with pure helium, so the improvement of overall regenerator performance can be obtained. Experiments have been done with helium-hydrogen mixture in a coaxial valveless pulse tube refrigerator. Experimental results show that the cooling capacity with He-H2 mixture is 10~20 percent larger than that with pure helium, which is in coincidence with the theoretical analysis.

  18. Effects of multi-jet coupling on propulsive performance in underwater pulsed jets

    CERN Document Server

    Athanassiadis, Athanasios G

    2016-01-01

    Despite the importance of pulsed jets for underwater propulsion, the effect of multiple-jet interactions remains poorly understood. We experimentally investigate how interactions between neighboring jets in a pulsed-jet thruster affect the thruster's propulsive performance. Using high-speed fluorescence imaging, we investigate the mutual influence of two pulsed jets under conditions relevant to low-speed maneuvering in a vehicle ($Re\\approx350,$ $L/D\\leq2$). Thrust production and propulsive efficiency are evaluated for different nozzle spacings using a new force estimation technique based on the fluorescence data. This analysis reveals that, compared to non-interacting jets, the efficiency and thrust generated by the pair of interacting jets can fall by as much as 10\\% when the jets are brought into close proximity. Empirically, the thrust $T$ falls off with the non-dimensional jet spacing $\\widetilde{\\Delta}$ as $T=T_\\infty(1-Co \\widetilde{\\Delta}^{-6})$ for a thrust coupling coefficient $Co=2.04 \\pm 0.11.$ ...

  19. The effects of leaf litter nutrient pulses on Alliaria petiolata performance

    Directory of Open Access Journals (Sweden)

    Robert W. Heckman

    2015-08-01

    Full Text Available Nutrient pulses can facilitate species establishment and spread in new habitats, particularly when one species more effectively uses that nutrient pulse. Biological differences in nutrient acquisition between native and exotic species may facilitate invasions into a variety of habitats including deciduous forest understories. Alliaria petiolata (Bieb. Cavara & Grande is an important invader of deciduous forest understories throughout much of North America. These understory communities contain many species which perform the majority of their growth and reproduction before canopy closure in spring. Because A. petiolata is a wintergreen biennial that can be active during autumn and winter, it may utilize nutrients released from decaying leaf litter before its competitors. To investigate this we manipulated the timing of leaf litter addition (fall or spring and experimentally simulated the nutrient pulse from decaying leaves using artificial fertilizer. To determine whether A. petiolata affected the abundance of understory competitors, we also removed A. petiolata from one treatment. A. petiolata that received early nutrients exhibited greater growth. Treatments receiving fall leaf litter or artificial nutrients had greater A. petiolata adult biomass than plots receiving spring nutrient additions (leaf litter or artificial nutrients. However, fall leaf litter addition had no effect on the richness of competitor species. Thus, wintergreen phenology may contribute to the spread of A. petiolata through deciduous forest understories, but may not explain community-level impacts of A. petiolata in deciduous forests.

  20. In vitro biological performance of minerals substituted hydroxyapatite coating by pulsed electrodeposition method

    Energy Technology Data Exchange (ETDEWEB)

    Gopi, Dhanaraj, E-mail: dhanaraj_gopi@yahoo.com [Department of Chemistry, Periyar University, Salem 636 011, Tamilnadu (India); Centre for Nanoscience and Nanotechnology, Periyar University, Salem 636 011, Tamilnadu (India); Karthika, Arumugam; Nithiya, Subramani [Department of Chemistry, Periyar University, Salem 636 011, Tamilnadu (India); Kavitha, Louis [Centre for Nanoscience and Nanotechnology, Periyar University, Salem 636 011, Tamilnadu (India); Department of Physics, Periyar University, Salem 636 011, Tamilnadu (India)

    2014-03-01

    The present study deals with the optimization of minerals (Sr, Mg and Zn) substituted hydroxyapatite coatings (M-HAP) at different pulse on and off time (1 s, 2 s, 3 s and 4 s) by pulsed electrodeposition method. The formation of M-HAP coating was investigated using Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction studies (XRD). The morphological features and the content of Sr, Mg and Zn ions in M-HAP coated Ti–6Al–4V were investigated by high resolution scanning electron microscopy (HRSEM) and energy dispersive X-ray analysis (EDAX). The electrochemical studies were performed for M-HAP coated Ti–6Al–4V in simulated body fluid which exhibited better corrosion resistance at the prolonged pulse off time. The in vitro cell adhesion test revealed that the M-HAP coating is found appropriate for the formation of new cell growth which proves the enhanced biocompatible nature of the coating. Thus the M-HAP coating will serve as a potential candidate in orthopedic applications. - Highlights: • We successfully achieved minerals substituted HAP coatings on Ti alloy by PED method. • The M-HAP coated Ti alloy exhibited better bioresistivity in SBF. • The as-coated sample showed antimicrobial activity and better cell viability. • The in vitro test displayed the formation of new cell growth. • The M-HAP coating can serve as a better candidate in orthopedic applications.

  1. Nanoparticles for solid rocket propulsion

    Energy Technology Data Exchange (ETDEWEB)

    Galfetti, L [Politecnico di Milano, SPLab, Milan (Italy); De Luca, L T [Politecnico di Milano, SPLab, Milan (Italy); Severini, F [Politecnico di Milano, SPLab, Milan (Italy); Meda, L [Polimeri Europa, Istituto G Donegani, Novara (Italy); Marra, G [Polimeri Europa, Istituto G Donegani, Novara (Italy); Marchetti, M [Universita di Roma ' La Sapienza' , Dipartimento di Ingegneria Aerospaziale ed Astronautica, Rome (Italy); Regi, M [Universita di Roma ' La Sapienza' , Dipartimento di Ingegneria Aerospaziale ed Astronautica, Rome (Italy); Bellucci, S [INFN, Laboratori Nazionali di Frascati, Frascati (Italy)

    2006-08-23

    The characterization of several differently sized aluminium powders, by BET (specific surface), EM (electron microscopy), XRD (x-ray diffraction), and XPS (x-ray photoelectron spectroscopy), was performed in order to evaluate their application in solid rocket propellant compositions. These aluminium powders were used in manufacturing several laboratory composite solid rocket propellants, based on ammonium perchlorate (AP) as oxidizer and hydroxil-terminated polybutadiene (HTPB) as binder. The reference formulation was an AP/HTPB/Al composition with 68/17/15% mass fractions respectively. The ballistic characterization of the propellants, in terms of steady burning rates, shows better performance for propellant compositions employing nano-aluminium when compared to micro-aluminium. Results obtained in the pressure range 1-70 bar show that by increasing the nano-Al mass fraction or decreasing the nano-Al size, larger steady burning rates are measured with essentially the same pressure sensitivity.

  2. Nanoparticles for solid rocket propulsion

    Science.gov (United States)

    Galfetti, L.; DeLuca, L. T.; Severini, F.; Meda, L.; Marra, G.; Marchetti, M.; Regi, M.; Bellucci, S.

    2006-08-01

    The characterization of several differently sized aluminium powders, by BET (specific surface), EM (electron microscopy), XRD (x-ray diffraction), and XPS (x-ray photoelectron spectroscopy), was performed in order to evaluate their application in solid rocket propellant compositions. These aluminium powders were used in manufacturing several laboratory composite solid rocket propellants, based on ammonium perchlorate (AP) as oxidizer and hydroxil-terminated polybutadiene (HTPB) as binder. The reference formulation was an AP/HTPB/Al composition with 68/17/15% mass fractions respectively. The ballistic characterization of the propellants, in terms of steady burning rates, shows better performance for propellant compositions employing nano-aluminium when compared to micro-aluminium. Results obtained in the pressure range 1-70 bar show that by increasing the nano-Al mass fraction or decreasing the nano-Al size, larger steady burning rates are measured with essentially the same pressure sensitivity.

  3. PERFORMANCE EVALUATION OF LOX AND LH2 TURBOPUMP TURBINES FOR A 10 TON THRUST LOX/LH2 ROCKET ENGINE

    OpenAIRE

    HASHIMOTO, Ryohei; Kamijo, Kenjiro; Watanabe, Yoshiaki; Hasegawa, Satoshi; Fujita, Toshihiko; 橋本, 亮平; 上絛, 謙二郎; 渡辺, 義明; 長谷川, 敏; 藤田, 敏彦

    1981-01-01

    The aerodynamic performance evaluation of the pump-drive turbines for a 10 ton thrust liquid oxygen and liquid hydrogen (LOX and LH2) gas generator cycle propulsion system, which has dual-shaft series turbines, was tested mainly using cold nitrogen gas. At design equivalent speed and pressure ratio, the LOX turbine static efficiency was about 35 percent compared to the design value of 32.8 percent. The LH2 turbine static efficiency was very close to the design value of 45 percent. Equivalent ...

  4. Computational modeling of nuclear thermal rockets

    Science.gov (United States)

    Peery, Steven D.

    1993-01-01

    The topics are presented in viewgraph form and include the following: rocket engine transient simulation (ROCETS) system; ROCETS performance simulations composed of integrated component models; ROCETS system architecture significant features; ROCETS engineering nuclear thermal rocket (NTR) modules; ROCETS system easily adapts Fortran engineering modules; ROCETS NTR reactor module; ROCETS NTR turbomachinery module; detailed reactor analysis; predicted reactor power profiles; turbine bypass impact on system; and ROCETS NTR engine simulation summary.

  5. Influence of Pulse Shaping Filters on PAPR Performance of Underwater 5G Communication System Technique: GFDM

    Directory of Open Access Journals (Sweden)

    Jinqiu Wu

    2017-01-01

    Full Text Available Generalized frequency division multiplexing (GFDM is a new candidate technique for the fifth generation (5G standard based on multibranch multicarrier filter bank. Unlike OFDM, it enables the frequency and time domain multiuser scheduling and can be implemented digitally. It is the generalization of traditional OFDM with several added advantages like the low PAPR (peak to average power ratio. In this paper, the influence of the pulse shaping filter on PAPR performance of the GFDM system is investigated and the comparison of PAPR in OFDM and GFDM is also demonstrated. The PAPR is restrained by selecting proper parameters and filters to make the underwater acoustic communication more efficient.

  6. Advanced Solid Rocket Launcher and Its Evolution

    Science.gov (United States)

    Morita, Yasuhiro; Imoto, Takayuki; Habu, Hiroto; Ohtsuka, Hirohito; Hori, Keiichi; Koreki, Takemasa; Fukuchi, Apollo; Uekusa, Yasuyuki; Akiba, Ryojiro

    The research on next generation solid propellant rockets is actively underway in various spectra. JAXA is developing the Advanced Solid Rocket (ASR) as a successor to the M-V launch vehicle, which was utilized over past ten years for space science programs including planetary missions. ASR is a result of the development of the next generation technology including a highly intelligent autonomous check-out system, which is connected to not only the solid rocket but also future transportation systems. It is expected to improve the efficiency of the launch system and double the cost performance. Far beyond this effort, the passion of the volunteers among the industry-government-academia cooperation has been united to establish the society of the freewheeling thinking “Next generation Solid Rocket Society (NSRS)”. It aims at a larger revolution than what the ASR provides so that the order of the cost performance is further improved. A study of the Low melting temperature Thermoplastic Propellant (LTP) is now at the experimental stage, which is expected to reform the manufacturing process of the solid rocket propellant and lead to a significant increase in cost performance. This paper indicates the direction of the big flow towards the next generation solid-propellant rockets: the concept of the intelligent ASR under development; and the innovation behind LTP.

  7. Laser Ignition Technology for Bi-Propellant Rocket Engine Applications

    Science.gov (United States)

    Thomas, Matt; Bossard, John; Early, Jim; Trinh, Huu; Dennis, Jay; Turner, James (Technical Monitor)

    2001-01-01

    This viewgraph presentation gives an overview of laser ignition technology for bipropellant rocket engines applications. The objectives of this project include: (1) the selection test chambers and flows; (2) definition of the laser ignition setup; (3) pulse format optimization; (4) fiber optic coupled laser ignition system analysis; and (5) chamber integration issues definition. The testing concludes that rocket combustion chamber laser ignition is imminent. Support technologies (multiplexing, window durability/cleaning, and fiber optic durability) are feasible.

  8. Water rocket - Electrolysis propulsion and fuel cell power

    Energy Technology Data Exchange (ETDEWEB)

    Carter, P H; Dittman, M D; Kare, J T; Militsky, F; Myers, B; Weisberg, A H

    1999-07-24

    Water Rocket is the collective name for an integrated set of technologies that offer new options for spacecraft propulsion, power, energy storage, and structure. Low pressure water stored on the spacecraft is electrolyzed to generate, separate, and pressurize gaseous hydrogen and oxygen. These gases, stored in lightweight pressure tanks, can be burned to generate thrust or recombined to produce electric power. As a rocket propulsion system, Water Rocket provides the highest feasible chemical specific impulse (-400 seconds). Even higher specific impulse propulsion can be achieved by combining Water Rocket with other advanced propulsion technologies, such as arcjet or electric thrusters. With innovative pressure tank technology, Water Rocket's specific energy [Wh/kg] can exceed that of the best foreseeable batteries by an order of magnitude, and the tanks can often serve as vehicle structural elements. For pulsed power applications, Water Rocket propellants can be used to drive very high power density generators, such as MHD devices or detonation-driven pulse generators. A space vehicle using Water Rocket propulsion can be totally inert and non-hazardous during assembly and launch. These features are particularly important for the timely development and flight qualification of new classes of spacecraft, such as microsats, nanosats, and refuelable spacecraft.

  9. Another Look at Rocket Thrust

    Science.gov (United States)

    Hester, Brooke; Burris, Jennifer

    2012-01-01

    Rocket propulsion is often introduced as an example of Newton's third law. The rocket exerts a force on the exhaust gas being ejected; the gas exerts an equal and opposite force--the thrust--on the rocket. Equivalently, in the absence of a net external force, the total momentum of the system, rocket plus ejected gas, remains constant. The law of…

  10. Another Look at Rocket Thrust

    Science.gov (United States)

    Hester, Brooke; Burris, Jennifer

    2012-01-01

    Rocket propulsion is often introduced as an example of Newton's third law. The rocket exerts a force on the exhaust gas being ejected; the gas exerts an equal and opposite force--the thrust--on the rocket. Equivalently, in the absence of a net external force, the total momentum of the system, rocket plus ejected gas, remains constant. The law of…

  11. Rocket University at KSC

    Science.gov (United States)

    Sullivan, Steven J.

    2014-01-01

    "Rocket University" is an exciting new initiative at Kennedy Space Center led by NASA's Engineering and Technology Directorate. This hands-on experience has been established to develop, refine & maintain targeted flight engineering skills to enable the Agency and KSC strategic goals. Through "RocketU", KSC is developing a nimble, rapid flight engineering life cycle systems knowledge base. Ongoing activities in RocketU develop and test new technologies and potential customer systems through small scale vehicles, build and maintain flight experience through balloon and small-scale rocket missions, and enable a revolving fresh perspective of engineers with hands on expertise back into the large scale NASA programs, providing a more experienced multi-disciplined set of systems engineers. This overview will define the Program, highlight aspects of the training curriculum, and identify recent accomplishments and activities.

  12. Effect of Reverse Pulse Current Duration on the Corrosion and Wear Performance of Ni-W Nanolaminate Coatings

    Science.gov (United States)

    Shreeram, Devesh Dadhich; Bedekar, Vikram; Li, Shengxi; Jagtap, Rohit; Cong, Hongbo; Doll, Gary L.

    2017-08-01

    The effects of varying the reverse pulse current duration (τ = 0 s, 1 s, 5 s, and 10 s) were evaluated on the composition, crystallinity, hardness, corrosion resistance, and tribological performance of nanolaminate Ni-W coatings deposited by pulsed reverse current electrodeposition. With the deposition conditions used in this study, it was found that a reverse current duration of τ = 1 s produced a coating that was both highly corrosion resistant and wear resistant.

  13. Performance of dynamical decoupling in bosonic environments and under pulse-timing fluctuations

    Science.gov (United States)

    Teixeira, W. S.; Kapale, K. T.; Paternostro, M.; Semião, F. L.

    2016-12-01

    We study the suppression of qubit dephasing through Uhrig dynamical decoupling (UDD) in nontrivial environments modeled within the spin-boson formalism. In particular, we address the case of (i) a qubit coupled to a bosonic bath with power-law spectral density, and (ii) a qubit coupled to a single harmonic oscillator that dissipates energy into a bosonic bath, which embodies an example of a structured bath for the qubit. We then model the influence of random time jitter in the UDD protocol by sorting pulse-application times from Gaussian distributions centered at appropriate values dictated by the optimal protocol. In case (i) we find that, when few pulses are applied and a sharp cutoff is considered, longer coherence times and robust UDD performances (against random timing errors) are achieved for a super-Ohmic bath. On the other hand, when an exponential cutoff is considered, a super-Ohmic bath is undesirable. In case (ii) the best scenario is obtained for an overdamped harmonic motion. Our study provides relevant information for the implementation of optimized schemes for the protection of quantum states from decoherence.

  14. Improved hybrid rocket fuel

    Science.gov (United States)

    Dean, David L.

    1995-01-01

    McDonnell Douglas Aerospace, as part of its Independent R&D, has initiated development of a clean burning, high performance hybrid fuel for consideration as an alternative to the solid rocket thrust augmentation currently utilized by American space launch systems including Atlas, Delta, Pegasus, Space Shuttle, and Titan. It could also be used in single stage to orbit or as the only propulsion system in a new launch vehicle. Compared to solid propellants based on aluminum and ammonium perchlorate, this fuel is more environmentally benign in that it totally eliminates hydrogen chloride and aluminum oxide by products, producing only water, hydrogen, nitrogen, carbon oxides, and trace amounts of nitrogen oxides. Compared to other hybrid fuel formulations under development, this fuel is cheaper, denser, and faster burning. The specific impulse of this fuel is comparable to other hybrid fuels and is between that of solids and liquids. The fuel also requires less oxygen than similar hybrid fuels to produce maximum specific impulse, thus reducing oxygen delivery system requirements.

  15. Developments in REDES: The Rocket Engine Design Expert System

    Science.gov (United States)

    Davidian, Kenneth O.

    1990-01-01

    The Rocket Engine Design Expert System (REDES) was developed at NASA-Lewis to collect, automate, and perpetuate the existing expertise of performing a comprehensive rocket engine analysis and design. Currently, REDES uses the rigorous JANNAF methodology to analyze the performance of the thrust chamber and perform computational studies of liquid rocket engine problems. The following computer codes were included in REDES: a gas properties program named GASP; a nozzle design program named RAO; a regenerative cooling channel performance evaluation code named RTE; and the JANNAF standard liquid rocket engine performance prediction code TDK (including performance evaluation modules ODE, ODK, TDE, TDK, and BLM). Computational analyses are being conducted by REDES to provide solutions to liquid rocket engine thrust chamber problems. REDES was built in the Knowledge Engineering Environment (KEE) expert system shell and runs on a Sun 4/110 computer.

  16. Nitrous Oxide/Paraffin Hybrid Rocket Engines

    Science.gov (United States)

    Zubrin, Robert; Snyder, Gary

    2010-01-01

    Nitrous oxide/paraffin (N2OP) hybrid rocket engines have been invented as alternatives to other rocket engines especially those that burn granular, rubbery solid fuels consisting largely of hydroxyl- terminated polybutadiene (HTPB). Originally intended for use in launching spacecraft, these engines would also be suitable for terrestrial use in rocket-assisted takeoff of small airplanes. The main novel features of these engines are (1) the use of reinforced paraffin as the fuel and (2) the use of nitrous oxide as the oxidizer. Hybrid (solid-fuel/fluid-oxidizer) rocket engines offer advantages of safety and simplicity over fluid-bipropellant (fluid-fuel/fluid-oxidizer) rocket en - gines, but the thrusts of HTPB-based hybrid rocket engines are limited by the low regression rates of the fuel grains. Paraffin used as a solid fuel has a regression rate about 4 times that of HTPB, but pure paraffin fuel grains soften when heated; hence, paraffin fuel grains can, potentially, slump during firing. In a hybrid engine of the present type, the paraffin is molded into a 3-volume-percent graphite sponge or similar carbon matrix, which supports the paraffin against slumping during firing. In addition, because the carbon matrix material burns along with the paraffin, engine performance is not appreciably degraded by use of the matrix.

  17. A3 Subscale Rocket Hot Fire Testing

    Science.gov (United States)

    Saunders, G. P.; Yen, J.

    2009-01-01

    This paper gives a description of the methodology and results of J2-X Subscale Simulator (JSS) hot fire testing supporting the A3 Subscale Diffuser Test (SDT) project at the E3 test facility at Stennis Space Center, MS (SSC). The A3 subscale diffuser is a geometrically accurate scale model of the A3 altitude simulating rocket test facility. This paper focuses on the methods used to operate the facility and obtain the data to support the aerodynamic verification of the A3 rocket diffuser design and experimental data quantifying the heat flux throughout the facility. The JSS was operated at both 80% and 100% power levels and at gimbal angle from 0 to 7 degrees to verify the simulated altitude produced by the rocket-rocket diffuser combination. This was done with various secondary GN purge loads to quantify the pumping performance of the rocket diffuser. Also, special tests were conducted to obtain detailed heat flux measurements in the rocket diffuser at various gimbal angles and in the facility elbow where the flow turns from vertical to horizontal upstream of the 2nd stage steam ejector.

  18. The XQC microcalorimeter sounding rocket: a stable LTD platform 30 seconds after rocket motor burnout

    Energy Technology Data Exchange (ETDEWEB)

    Porter, F.S. E-mail: frederick.s.porter@gsfc.nasa.gov; Almy, R.; Apodaca, E.; Figueroa-Feliciano, E.; Galeazzi, M.; Kelley, R.; McCammon, D.; Stahle, C.K.; Szymkowiak, A.E.; Sanders, W.T

    2000-04-07

    The XQC microcalorimeter sounding rocket experiment is designed to provide a stable thermal environment for an LTD detector system within 30 s of the burnout of its second stage rocket motor. The detector system used for this instrument is a 36-pixel microcalorimeter array operated at 60 mK with a single-stage adiabatic demagnetization refrigerator (ADR). The ADR is mounted on a space-pumped liquid helium tank with vapor cooled shields which is vibration isolated from the rocket structure. We present here some of the design and performance details of this mature LTD instrument, which has just completed its third suborbital flight.

  19. 高精度小型固体火箭发动机184性能检测系统研究%Research on the Performance Detecting System of High-precision Small-scale Solid Rocket Motor

    Institute of Scientific and Technical Information of China (English)

    冯喜平; 董韬; 李进贤; 曹琪

    2011-01-01

    针对固体火箭发动机研制和生产中的性能检测需求,基于柔性试验架建立试验平台,采用虚拟仪器技术搭建测控平台,使用LabvieW7.1开发一套包含参数标定、数据测量、数据处理等模块的固体火箭发动机性能检测试验测控软件,构建了固体火箭发动机性能检测系统。通过对标准发动机进行测试,结果表明:该系统实现了发动机参数的现场方便标定、发动机数据的高速采集和实验数据的快速处理,测量精度达到0.3%的工程要求,并同步监测了整个发动机的工作过程,满足了发动机性能检测的高精度要求。%According to the performance detecting requirements in development and manufacture of solid rocket motor, a test platform has been set up based on flexible test stand, in which the measurement and control platform has been built using virtual instrument technology ; a set of solid rocket motor ground test performance detecting software including parameter calibration model, data measure model and data processing model have been developed based on the LabViewT. 1 ; and the solid rocket motor performance detecting system was built. The application results through testing normative solid rocket motor show that: this system could actualize parameter calibration expediently, experimental data collection and processing rapidly, even reach the measurement precision by 0.3% required in projects and could monitor the testing process of solid rocket motor simultaneously, which satisfied high-precision requirements of motor performance detection.

  20. Effect of vitamin B12 pulse addition on the performance of cobalt deprived anaerobic granular sludge bioreactors

    KAUST Repository

    Fermoso, Fernando G.

    2010-07-01

    The effect of a pulse addition of vitamin B12 as cobalt source to restore the performance of cobalt depleted methanol-fed bioreactors was investigated. One upflow anaerobic sludge bed (UASB) reactor was supplied with a pulse of vitamin B12, and its operation was compared to that of another cobalt depleted UASB reactor to which a pulse of CoCl2 was given. The addition of cobalt in the form of CoCl2 supplies enough cobalt to restore methanogenesis and maintain full methanol degradation coupled to methane production during more than 35 days after the CoCl2 pulse. Similar to CoCl2, pulse addition of vitamin B12 supplies enough cobalt to maintain full methanol degradation during more than 35 days after the pulse. However, the specific methanogenic activities (SMAs) of the sludge in the vitamin B12 supplied reactor were around 3 times higher than the SMA of the sludge from the CoCl2 supplied reactor at the same sampling times. An appropriate dosing strategy (repeated pulse dosing) combined with the choice of vitamin B12 as the cobalt species is suggested as a promising dosing strategy for methanol-fed anaerobic bioreactors limited by the micronutrient cobalt. © 2010 Elsevier Ltd. All rights reserved.

  1. Determination of neomycin in water samples by high performance anion chromatography with pulsed amperometric detection

    Institute of Scientific and Technical Information of China (English)

    Bin Guan; Dong Xing Yuan

    2007-01-01

    A simple, fast and reliable method, using high performance anion chromatography with pulsed amperometric detection, had been developed for the analysis of neomycin in water samples. The elution and separation were carried out with an isocratic mobile phase, containing 10 mmol/L NaOH. The influence of the concentration and pH of the mobile phase on the separation and detection was investigated. A quadruple-potential waveform used for the detection was optimized. The detection limit of neomycin was down to 0.027 μg/mL. The linearity of neomycin calibration curve ranged from 0.050 to 0.505 μg/mL with correlation coefficient of0.9997. R.S.D. (n= 11) was 4.0%.

  2. Diffusion barrier performance of pulsed laser deposited amorphous tungsten carbide films

    Science.gov (United States)

    Ghaisas, Smita

    1991-12-01

    The performance of pulsed laser deposited tungsten carbide films as diffusion barriers between a Si substrate and an Al overlayer has been investigated. Four-point probe measurement of resistance is employed to monitor the electrical stability of the Al/WC/Si metallization schemes upon thermal annealing in a vacuum for 30 min in a temperature range from 100 to 500 °C. The Glancing angle x-ray diffraction technique has been used to characterize the as-deposited as well as annealed samples. To study the metallurgical interaction between Al overlayer and the barrier film, experiments on isothermal annealings are carried out. The data obtained have been used to estimate the activation energy for the formation of the intermetallic compound WAl12. Morphological features of the annealed samples have been obtained by employing the technique of scanning electron microscopy.

  3. Preliminary performance analysis of the advanced pulse compression noise radar waveform

    Science.gov (United States)

    Govoni, Mark A.; Moyer, Lee R.

    2012-06-01

    Noise radar systems encounter target fluctuation behavior similar to that of conventional systems. For noise radar systems, however, the fluctuations are not only dictated by target composition and geometry, but also by the non-uniform power envelope of their random transmit signals. This third dependency is of interest and serves as the basis for the preliminary analysis conducted in this manuscript. General conclusions are drawn on the implications of having a random power envelope and the impacts it could have on both the transmit and receive processes. Using an advanced pulse compression noise (APCN) radar waveform as the constituent signal, a computer simulation aids in quantifying potential losses and the impacts they might have on the detection performance of a real radar system.

  4. Rocket noise - A review

    Science.gov (United States)

    McInerny, S. A.

    1990-10-01

    This paper reviews what is known about far-field rocket noise from the controlled studies of the late 1950s and 1960s and from launch data. The peak dimensionless frequency, the dependence of overall sound power on exhaust parameters, and the directivity of the overall sound power of rockets are compared to those of subsonic jets and turbo-jets. The location of the dominant sound source in the rocket exhaust plume and the mean flow velocity in this region are discussed and shown to provide a qualitative explanation for the low peak Strouhal number, fD(e)/V(e), and large angle of maximum directivity. Lastly, two empirical prediction methods are compared with data from launches of a Titan family vehicle (two, solid rocket motors of 5.7 x 10 to the 6th N thrust each) and the Saturn V (five, liquid oxygen/rocket propellant engines of 6.7 x 10 to the 6th N thrust, each). The agreement is favorable. In contrast, these methods appear to overpredict the far-field sound pressure levels generated by the Space Shuttle.

  5. Design and performance of a pulse transformer based on Fe-based nanocrystalline core.

    Science.gov (United States)

    Yi, Liu; Xibo, Feng; Lin, Fuchang

    2011-08-01

    A dry-type pulse transformer based on Fe-based nanocrystalline core with a load of 0.88 nF, output voltage of more than 65 kV, and winding ratio of 46 is designed and constructed. The dynamic characteristics of Fe-based nanocrystalline core under the impulse with the pulse width of several microseconds were studied. The pulse width and incremental flux density have an important effect on the pulse permeability, so the pulse permeability is measured under a certain pulse width and incremental flux density. The minimal volume of the toroidal pulse transformer core is determined by the coupling coefficient, the capacitors of the resonant charging circuit, incremental flux density, and pulse permeability. The factors of the charging time, ratio, and energy transmission efficiency in the resonant charging circuit based on magnetic core-type pulse transformer are analyzed. Experimental results of the pulse transformer are in good agreement with the theoretical calculation. When the primary capacitor is 3.17 μF and charge voltage is 1.8 kV, a voltage across the secondary capacitor of 0.88 nF with peak value of 68.5 kV, rise time (10%-90%) of 1.80 μs is obtained.

  6. Flutter Analysis of RX-420 Balistic Rocket Fin Involving Rigid Body Modes of Rocket Structures

    OpenAIRE

    Novi Andria

    2013-01-01

    Flutter is a phenomenon that has brought a catastrophic failure to the flight vehicle structure. In this experiment, flutter was analyzed for its symmetric and antisymmetric configuration to understand the effect of rocket rigid modes to the fin flutter characteristic. This research was also expected to find out the safety level of RX-420 structure design. The analysis was performed using half rocket model. Fin structure used in this research was a fin which has semispan 600 mm, thickness 12 ...

  7. Effect of pulsed plasma nitriding on mechanical and tribological performance of Ck45 steel.

    Science.gov (United States)

    Rastkar, A R; Kiani, A; Alvand, F; Shokri, B; Amirzadeh, M

    2011-06-01

    We studied the mechanical properties and wear performance of AISI 1045 (Ck45) carbon steel under the influence of pulsed plasma nitriding. The treatments were performed at temperatures of 500 and 550 degrees C in N2:H2 gas ratios of 1:3 and 3:1 and the working pressure of 10 mbar for 1 to 4 hours. Samples were examined by X-ray diffraction, optical, electron and atomic force microscopy, microhardness tests, roughness measurements and wear tests. Nitride layers were mainly composed of epsilon-(Fe2-3N) or gamma'-(Fe4N) depending on the gas ratio and/or temperature and time. When the nitriding time is increased, the composition of the compound layer varies from monophase gamma'-(Fe4N) to the two phase of epsilon-(Fe2-3N) and gamma'-(Fe4N). The highest thickness and hardness of the layers were obtained at 550 degrees C in the N2:H2 gas ratios of 3:1 for 4 h. The topographical evolution and surface roughness of the samples showed that all the roughness parameters increase with increasing the temperature. The friction coefficient of all samples was higher than that of untreated material. Wear performance of all nitrided samples was significantly better than that of untreated material.

  8. Rocket Flight Path

    Directory of Open Access Journals (Sweden)

    Jamie Waters

    2014-09-01

    Full Text Available This project uses Newton’s Second Law of Motion, Euler’s method, basic physics, and basic calculus to model the flight path of a rocket. From this, one can find the height and velocity at any point from launch to the maximum altitude, or apogee. This can then be compared to the actual values to see if the method of estimation is a plausible. The rocket used for this project is modeled after Bullistic-1 which was launched by the Society of Aeronautics and Rocketry at the University of South Florida.

  9. Fabrications of Polyaniline Films by Pulse Electrodeposition in Acidic Solutions with Different Anions and Their Thermoelectric Performances

    Science.gov (United States)

    Yang, Weifang; Xu, Han; Li, Yuanyuan; Wang, Wei

    2017-08-01

    Polymerization of aniline was prepared by the pulse potentiostatic method in H3PO4, HClO4 and H2SO4 acidic solutions. The morphologies and thermoelectric performances were analyzed by scanning electron microscopy, Seebeck coefficient ( S) and resistivity ( R) measurements. The results show that flake polyaniline (PANI) films can be obtained in H3PO4 and HClO4 acidic solutions, and porous PANI films with nanofiber-overlapped structures can be prepared in H2SO4 solution under the same pulse parameters. PANI films prepared in the three solutions are all p-type thermoelectric materials. PANI films polymerized in H2SO4 solution possess the highest S (30.2 μV K-1) and lowest R (1.6 × 10-3 Ω m) compared with those prepared in H3PO4 and HClO4 solutions, indicating that nanofiber-overlapped structures formed in H2SO4 solution contribute better thermoelectric performance. In addition, the effects of pulse parameters (anodic potential φ a, anodic pulse duration t a and cathodic pulse duration t c) on the surface morphologies and thermoelectric performances of PANI films were systematically investigated.

  10. Rockets in World War I

    Science.gov (United States)

    2004-01-01

    World War I enlisted rockets once again for military purposes. French pilots rigged rockets to the wing struts of their airplanes and aimed them at enemy observation balloons filled with highly inflammable hydrogen.

  11. An Evaluation Of Rocket Parameters

    Directory of Open Access Journals (Sweden)

    J. N. Beri

    1959-07-01

    Full Text Available The dependence of conventional parameters of internal ballistics of Solid Propellant Rockets using external burning cruciform charge, on the geometry of charge aad rocket motor is discussed and results applied in a special case.

  12. Numerical investigation and optimization of multi-pulse CHI spheromak performance

    Science.gov (United States)

    O'Bryan, J. B.; Romero-Talamas, C. A.; Woodruff, S.

    2015-11-01

    Nonlinear extended-MHD computation with the NIMROD code is used to explore spheromak formation and sustainment with multi-pulse coaxial helicity injection (CHI). The goal of this research is to optimize spheromak performance in order to find candidate modes of operation for future experimental studies. We are modeling multiple specific shots from the Sustained Spheromak Physics eXperiment (SSPX) to both diagnose the parameters that affect efficiency--in particular, how the injector current and bias flux affect plasma confinement and magnetic helicity content relative to injected power--and to validate the numerical model. Preliminary results show quantitative agreement between several synthetic and experimental diagnostic measurements. The results also find--in addition to changing the magnetic topology and being the mechanism for poloidal flux amplification [E.B. Hooper et al. PPCF 2012]--the non-axisymmetric column mode decreases the decay rate of magnetic helicity relative to the injected current. Operational regimes will eventually be extended beyond those achieved in SSPX. We are also exploring the effect of the flux conserver and injector geometries on spheromak performance. This work is supported by DARPA under grant no. N66001-14-1-4044.

  13. Enhanced Photocatalytic Performance Depending on Morphology of Bismuth Vanadate Thin Film Synthesized by Pulsed Laser Deposition.

    Science.gov (United States)

    Jeong, Sang Yun; Choi, Kyoung Soon; Shin, Hye-Min; Kim, Taemin Ludvic; Song, Jaesun; Yoon, Sejun; Jang, Ho Won; Yoon, Myung-Han; Jeon, Cheolho; Lee, Jouhahn; Lee, Sanghan

    2017-01-11

    We have fabricated high quality bismuth vanadate (BiVO4) polycrystalline thin films as photoanodes by pulsed laser deposition (PLD) without a postannealing process. The structure of the grown films is the photocatalytically active phase of scheelite-monoclinic BiVO4 which was obtained by X-ray diffraction (XRD) analysis. The change of surface morphology for the BIVO4 thin films depending on growth temperature during synthesis has been observed by scanning electron microscopy (SEM), and its influence on water splitting performance was investigated. The current density of the BiVO4 film grown on a glass substrate covered with fluorine-doped tin oxide (FTO) at 230 °C was as high as 3.0 mA/cm(2) at 1.23 V versus the potential of the reversible hydrogen electrode (VRHE) under AM 1.5G illumination, which is the highest value so far in previously reported BiVO4 films grown by physical vapor deposition (PVD) methods. We expect that doping of transition metal or decoration of oxygen evolution catalyst (OEC) in our BiVO4 film might further enhance the performance.

  14. Experimental and numerical investigation on performance of a double inlet type cryogenic pulse tube refrigerator

    Science.gov (United States)

    Biswas, Animesh; Ghosh, Subrata K.

    2016-09-01

    A helium filled double inlet pulse tube refrigerator (DIPTR) has been designed, built and operated to provide cryogenic cooling. The experimental studies have been carried out to characterize the performance of the DIPTR at various values of the mean pressure of helium (0.7-1.5 MPa), amplitudes of pressure oscillations, and sizes of orifice opening. A detailed time-dependent three dimensional computational fluid dynamics (CFD) model of the DIPTR has also been developed to predict its performance. In the CFD model, the continuity, momentum and energy equations have been solved for both the refrigerant gas (helium) and the porous media regions (the regenerator and heat exchangers) in the DIPTR. The computational results have been compared with specific experimental results to validate the numerical model. The results predicted by the model show better results as compared to experimental results, as the effects of wall thicknesses and natural convective losses of the various components of the DIPTR to the surroundings have not been included in the model.

  15. The effect of easily ionized elements Na and K on the performance of pulsed plasma thruster using water propellant

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    In view of the low thrust power ratio caused by the high resistance of pulsed plasma thruster using water propellant,the paper argues that the easily ionized elements Na and K with low ionic potentials are added in the water propellant to improve its performance. The measurement of the discharging current and plasma emission spectrographic analysis prove the improvement. The experiments show that the elements Na and K have certain effect on the improvement of the performance of pulsed plasma thruster: In comparison with water propellant,the NaCl and KCl water propellant has a lower total resistance and a higher ratio of thruster power and specific impulse,and the NaCl water propellant has a slightly stronger effect on pulsed plasma thruster than the KCl. The plasma emission spectrographic analysis is in consistent with the experiment of measuring the discharging current: The elements Na and K can intensify the plasma emission spectrographic signal.

  16. High performance diamond-like carbon layers obtained by pulsed laser deposition for conductive electrode applications

    Science.gov (United States)

    Stock, F.; Antoni, F.; Le Normand, F.; Muller, D.; Abdesselam, M.; Boubiche, N.; Komissarov, I.

    2017-09-01

    For the future, one of the biggest challenge faced to the technologies of flat panel display and various optoelectronic and photovoltaic devices is to find an alternative to the use of transparent conducting oxides like ITO. In this new approach, the objective is to grow high conductive thin-layer graphene (TLG) on the top of diamond-like carbon (DLC) layers presenting high performance. DLC prepared by pulsed laser deposition (PLD) have attracted special interest due to a unique combination of their properties, close to those of monocrystalline diamond, like its transparency, hardness and chemical inertia, very low roughness, hydrogen-free and thus high thermal stability up to 1000 K. In our future work, we plane to explore the synthesis of conductive TLG on top of insulating DLC thin films. The feasibility and obtained performances of the multi-layered structure will be explored in great details in the short future to develop an alternative to ITO with comparable performance (conductivity of transparency). To select the best DLC candidate for this purpose, we focus this work on the physicochemical properties of the DLC thin films deposited by PLD from a pure graphite target at two wavelengths (193 and 248 nm) at various laser fluences. A surface graphenization process, as well as the required efficiency of the complete structure (TLG/DLC) will clearly be related to the DLC properties, especially to the initial sp3/sp2 hybridization ratio. Thus, an exhaustive description of the physicochemical properties of the DLC layers is a fundamental step in the research of comparable performance to ITO.

  17. Influence of phenylacetic acid pulses on anaerobic digestion performance and archaeal community structure in WWTP sewage sludge digesters.

    Science.gov (United States)

    Cabrol, Léa; Urra, Johana; Rosenkranz, Francisca; Kroff, Pablo Araya; Plugge, Caroline M; Lesty, Yves; Chamy, Rolando

    2015-01-01

    The effect of phenylacetic acid (PAA) pulses on anaerobic digestion (AD) performance and archaeal community structure was evaluated in anaerobic digesters treating sewage sludge from a wastewater treatment plant (WWTP). Four pilot-scale continuous stirred tank reactors were set up at a full-scale municipal WWTP in Santiago de Chile, and fed with either primary or mixed sewage sludge. AD performance was evaluated by volatile fatty acid (VFA) and biogas production monitoring. Archaeal community structure was characterized by 16S rRNA denaturing gradient gel electrophoresis and band sequencing. In the primary sludge digester, a single PAA pulse at 200 mg L(-1) was sufficient to affect AD performance and archaeal community structure, resulting in long-term VFA accumulation, reduced biogas production and community shift from dominant acetoclastic (Methanosaeta concilii) to hydrogenotrophic (Methanospirillum hungatei) methanogens. By contrast, AD performance and archaeal community structure in the mixed sludge digester were stable and resistant to repeated PAA pulses at 200 and 600 mg L(-1). This work demonstrated that the effect of PAA pulses on methanogenic activity and archaeal community structure differed according to AD substrate, and suggests that better insights of the correlations between archaeal population dynamics and functional performance could help to better face toxic shocks in AD.

  18. Baking Soda and Vinegar Rockets

    Science.gov (United States)

    Claycomb, James R.; Zachary, Christopher; Tran, Quoc

    2009-01-01

    Rocket experiments demonstrating conservation of momentum will never fail to generate enthusiasm in undergraduate physics laboratories. In this paper, we describe tests on rockets from two vendors that combine baking soda and vinegar for propulsion. The experiment compared two analytical approximations for the maximum rocket height to the…

  19. Baking Soda and Vinegar Rockets

    Science.gov (United States)

    Claycomb, James R.; Zachary, Christopher; Tran, Quoc

    2009-01-01

    Rocket experiments demonstrating conservation of momentum will never fail to generate enthusiasm in undergraduate physics laboratories. In this paper, we describe tests on rockets from two vendors that combine baking soda and vinegar for propulsion. The experiment compared two analytical approximations for the maximum rocket height to the…

  20. Introduction to Rocket Propulsion

    Science.gov (United States)

    1991-12-01

    Von Braun; 1966. 4. Introduction to Ordnance Technology; IHSP 76-129; 1976. 5. Physics; D. Halliday and R. Resnick ; 1963. 6. Physics Tells Why: 0...to Luke Sky- walker in Star Wars when he said "Don’t get cocky." We never plan for EVERYTHING, though we like to think we do. As we’ve said, rocket

  1. Low toxicity rocket propellants

    NARCIS (Netherlands)

    Wink, J.

    2014-01-01

    Hydrazine (N2H4) and its hypergolic mate nitrogen tetroxide (N2O4) are used on virtually all spacecraft and on a large number of launch vehicles. In recent years however, there has been an effort in identifying and developing alternatives to replace hydrazine as a rocket propellant.

  2. This "Is" Rocket Science!

    Science.gov (United States)

    Keith, Wayne; Martin, Cynthia; Veltkamp, Pamela

    2013-01-01

    Using model rockets to teach physics can be an effective way to engage students in learning. In this paper, we present a curriculum developed in response to an expressed need for helping high school students review physics equations in preparation for a state-mandated exam. This required a mode of teaching that was more advanced and analytical…

  3. The Relativistic Rocket

    Science.gov (United States)

    Antippa, Adel F.

    2009-01-01

    We solve the problem of the relativistic rocket by making use of the relation between Lorentzian and Galilean velocities, as well as the laws of superposition of successive collinear Lorentz boosts in the limit of infinitesimal boosts. The solution is conceptually simple, and technically straightforward, and provides an example of a powerful…

  4. Rocketing to the Skies

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    ONE sunny morning,we startedfor Yanqi Lake,Huairou District,Beijing,to try“rocket bungy”,so farthe only facility for this sport inChina.On the way there,wequestioned our courage and heartendurance. Entering the gate we saw,towering over a banner saying,

  5. Low toxicity rocket propellants

    NARCIS (Netherlands)

    Wink, J.

    2014-01-01

    Hydrazine (N2H4) and its hypergolic mate nitrogen tetroxide (N2O4) are used on virtually all spacecraft and on a large number of launch vehicles. In recent years however, there has been an effort in identifying and developing alternatives to replace hydrazine as a rocket propellant.

  6. Measurement of Work Generation and Improvement in Performance of a Pulse Tube Engine

    Science.gov (United States)

    Hamaguchi, Kazuhiro; Futagi, Hiroaki; Yazaki, Taichi; Hiratsuka, Yoshikatsu

    Apart from double acting type engines, Stirling engines have either 2 pistons in 2 cylinders or 2 pistons in a single cylinder. Typically, the heater, regenerator and cooler are installed between the 2 pistons. The pulse tube engine, on the other hand, consists of a single piston in a single cylinder, a pulse tube, a heater, a regenerator, a cooler and a second cooler. For this paper, a simple prototype engine that uses air at normal atmospheric pressure as the working gas was fabricated. The oscillating velocity of the working gas in the pulse tube was measured using LDV, and the work flow emitting out of the pulse tube was observed. In addition, the effect of inserting heat storage material in the pulse tube on shaft power and indicated power was examined experimentally. A dramatic increase in the shaft power was achieved.

  7. Learning Pulse: a machine learning approach for predicting performance in self-regulated learning using multimodal data

    NARCIS (Netherlands)

    Di Mitri, Daniele; Scheffel, Maren; Drachsler, Hendrik; Börner, Dirk; Ternier, Stefaan; Specht, Marcus

    2017-01-01

    Learning Pulse explores whether using a machine learning approach on multimodal data such as heart rate, step count, weather condition and learning activity can be used to predict learning performance in self-regulated learning settings. An experiment was carried out lasting eight weeks involving Ph

  8. Influence of phenylacetic acid pulses on anaerobic digestion performance and archaeal community structure in WWTP sewage sludge digesters

    NARCIS (Netherlands)

    Cabrol, L.; Urra, J.; Rosenkranz, F.; Kroff, P.A.; Plugge, C.M.; Lesty, Y.; Chamy, R.

    2015-01-01

    The effect of phenylacetic acid (PAA) pulses on anaerobic digestion (AD) performance and archaeal community structure was evaluated in anaerobic digesters treating sewage sludge from a wastewater treatment plant (WWTP). Four pilot-scale continuous stirred tank reactors were set up at a full-scale

  9. Influence of phenylacetic acid pulses on anaerobic digestion performance and archaeal community structure in WWTP sewage sludge digesters

    NARCIS (Netherlands)

    Cabrol, L.; Urra, J.; Rosenkranz, F.; Kroff, P.A.; Plugge, C.M.; Lesty, Y.; Chamy, R.

    2015-01-01

    The effect of phenylacetic acid (PAA) pulses on anaerobic digestion (AD) performance and archaeal community structure was evaluated in anaerobic digesters treating sewage sludge from a wastewater treatment plant (WWTP). Four pilot-scale continuous stirred tank reactors were set up at a full-scale mu

  10. A pulse coding and decoding strategy to perform Lamb wave inspections using simultaneously multiple actuators

    Science.gov (United States)

    De Marchi, Luca; Marzani, Alessandro; Moll, Jochen; Kudela, Paweł; Radzieński, Maciej; Ostachowicz, Wiesław

    2017-07-01

    The performance of Lamb wave based monitoring systems, both in terms of diagnosis time and data complexity, can be enhanced by increasing the number of transducers used to actuate simultaneously the guided waves in the inspected medium. However, in case of multiple simultaneously-operated actuators the interference among the excited wave modes within the acquired signals has to be considered for the further processing. To this aim, in this work a code division strategy based on the Warped Frequency Transform is presented. At first, the proposed procedure encodes actuation pulses using Gold sequences. Next, for each considered actuator the acquired signals are compensated from dispersion by cross correlating the warped version of the actuated and received signals. Compensated signals form the base for a final wavenumber imaging meant at emphasizing defects and or anomalies by removing incident wavefield and edge reflections. The proposed strategy is tested numerically, and validated through an experiment in which guided waves are actuated in a plate by four piezoelectric transducers operating simultaneously.

  11. Characterisation of brewpub beer carbohydrates using high performance anion exchange chromatography coupled with pulsed amperometric detection.

    Science.gov (United States)

    Arfelli, Giuseppe; Sartini, Elisa

    2014-01-01

    High performance anion exchange chromatography (HPAEC) coupled with pulsed amperometric detection (PAD) was optimised in order to quantify mannose, maltose, maltotriose, maltotetraose, maltopentaose, maltohexaose and maltoheptaose content of beer. The method allows the determination of above mentioned oligosaccharides, in a single chromatographic run, without any pre-treatment. Limit of detection and limit of quantification were suitable for beer. Accuracy and repeatability were good for the entire amount considered. Once optimised HPAEC PAD for the specific matrix, the second goal of this research was to verify the possibility to discriminate beers, depending on their style. The carbohydrates content of brewpub commercial beers was very variable, ranging from 19.3 to 1469mg/L (mannose), 34.5 to 2882mg/L (maltose), 141.9 to 20731mg/L (maltotriose), 168.5 to 7650mg/L (maltotetraose), 20.1 to 2537mg/L (maltopentaose), 22.9 to 3295mg/L (maltohexaose), 8.5 to 2492mg/L (maltoeptaose), even in the same style of beer. However, the carbohydrates content was useful, jointed with other compounds amount, to discriminate different styles of beer. As a matter of fact, principal component analysis put in evidence beer differences considering some fermentation conditions and colour.

  12. CODEX sounding rocket wire grid collimator design

    Science.gov (United States)

    Shipley, Ann; Zeiger, Ben; Rogers, Thomas

    2011-05-01

    CODEX is a sounding rocket payload designed to operate in the soft x-ray (0.1-1.0 kV) regime. The instrument has a 3.25 degree square field of view that uses a one meter long wire grid collimator to create a beam that converges to a line in the focal plane. Wire grid collimator performance is directly correlated to the geometric accuracy of actual grid features and their relative locations. Utilizing a strategic combination of manufacturing and assembly techniques, this design is engineered for precision within the confines of a typical rocket budget. Expected resilience of the collimator under flight conditions is predicted by mechanical analysis.

  13. Regenerative Cooling for Liquid Rocket Engines

    Institute of Scientific and Technical Information of China (English)

    QiFeng

    1995-01-01

    Heat transfer in the thrust chamber is of great importance in the design of liquid propellant rocket engines.Regenerative cooling is and advanced method which can ensure not only the proper running but also higher performance of a rocket engine.The theoretical model is complicated,it relates to fluid bynamics,heat transfer,combustion.etc…,In this paper,a regenerative cooling model is presented.Effects such as radiation,heat transfer to environment,variable thermal properties and coking are included in the model.This model can be applied to all kinds of liquid propellant rocket engines as well as similar constructions.The modularized computer code is completed in the work.

  14. Computer modeling of electrical and thermal performance during bipolar pulsed radiofrequency for pain relief

    Energy Technology Data Exchange (ETDEWEB)

    Pérez, Juan J. [Instituto de Investigación Interuniversitario en Bioingeniería y Tecnología Orientada al Ser Humano, Universitat Politècnica de València, Valencia 46022 (Spain); Pérez-Cajaraville, Juan J. [Pain Unit and Department of Anesthesia and Critical Care, Clínica Universidad de Navarra, University of Navarra, Pamplona 31008 (Spain); Muñoz, Víctor [Neurotherm Spain, Barcelona 08303 (Spain); Berjano, Enrique, E-mail: eberjano@eln.upv.es [Biomedical Synergy, Electronic Engineering Department, Universitat Politècnica de València 46022 (Spain)

    2014-07-15

    Purpose: Pulsed RF (PRF) is a nonablative technique for treating neuropathic pain. Bipolar PRF application is currently aimed at creating a “strip lesion” to connect the electrode tips; however, the electrical and thermal performance during bipolar PRF is currently unknown. The objective of this paper was to study the temperature and electric field distributions during bipolar PRF. Methods: The authors developed computer models to study temperature and electric field distributions during bipolar PRF and to assess the possible ablative thermal effect caused by the accumulated temperature spikes, along with any possible electroporation effects caused by the electrical field. The authors also modeled the bipolar ablative mode, known as bipolar Continuous Radiofrequency (CRF), in order to compare both techniques. Results: There were important differences between CRF and PRF in terms of electrical and thermal performance. In bipolar CRF: (1) the initial temperature of the tissue impacts on temperature progress and hence on the thermal lesion dimension; and (2) at 37 °C, 6-min of bipolar CRF creates a strip thermal lesion between the electrodes when these are separated by a distance of up to 20 mm. In bipolar PRF: (1) an interelectrode distance shorter than 5 mm produces thermal damage (i.e., ablative effect) in the intervening tissue after 6 min of bipolar RF; and (2) the possible electroporation effect (electric fields higher than 150 kV m{sup −1}) would be exclusively circumscribed to a very small zone of tissue around the electrode tip. Conclusions: The results suggest that (1) the clinical parameters considered to be suitable for bipolar CRF should not necessarily be considered valid for bipolar PRF, and vice versa; and (2) the ablative effect of the CRF mode is mainly due to its much greater level of delivered energy than is the case in PRF, and therefore at same applied energy levels, CRF, and PRF are expected to result in same outcomes in terms of

  15. Improving Switching Performance of Power MOSFETs Used in High Rep-Rate, Short Pulse, High-Power Pulsers

    Energy Technology Data Exchange (ETDEWEB)

    Cook, E G

    2006-09-19

    As their switching and power handling characteristics improve, solid-state devices are finding new applications in pulsed power. This is particularly true of applications that require fast trains of short duration pulses. High voltage (600-1200V) MOSFETs are especially well suited for use in these systems, as they can switch at significant peak power levels and are easily gated on and off very quickly. MOSFET operation at the shortest pulse durations is not constrained by the intrinsic capabilities of the MOSFET, but rather by the capabilities of the gate drive circuit and the system physical layout. This project sought to improve MOSFET operation in a pulsed power context by addressing these issues. The primary goal of this project is to improve the switching performance of power MOSFETs for use in high rep-rate, short pulse, high-power applications by improving the design of the gate drive circuits and the circuit layouts used in these systems. This requires evaluation of new commercial gate drive circuits and upgrading the designs of LLNL-developed circuits. In addition, these circuits must be tested with the fastest available high-voltage power MOSFETs.

  16. Nonparametric Interference Suppression Using Cyclic Wiener Filtering: Pulse Shape Design and Performance Evaluation

    Directory of Open Access Journals (Sweden)

    Anass Benjebbour

    2008-02-01

    Full Text Available In the future, there will be a growing need for more flexible but efficient utilization of radio resources. Increased flexibility in radio transmission, however, yields a higher likelihood of interference owing to limited coordination among users. In this paper, we address the problem of flexible spectrum sharing where a wideband single carrier modulated signal is spectrally overlapped by unknown narrowband interference (NBI and where a cyclic Wiener filter is utilized for nonparametric NBI suppression at the receiver. The pulse shape design for the wideband signal is investigated to improve the NBI suppression capability of cyclic Wiener filtering. Specifically, two pulse shaping schemes, which outperform existing raised cosine pulse shaping schemes even for the same amount of excess bandwidth, are proposed. Based on computer simulation, the interference suppression capability of cyclic Wiener filtering is evaluated for both the proposed and existing pulse shaping schemes under several interference conditions and over both AWGN and Rayleigh fading channels.

  17. Nonparametric Interference Suppression Using Cyclic Wiener Filtering: Pulse Shape Design and Performance Evaluation

    Directory of Open Access Journals (Sweden)

    Benjebbour Anass

    2008-01-01

    Full Text Available Abstract In the future, there will be a growing need for more flexible but efficient utilization of radio resources. Increased flexibility in radio transmission, however, yields a higher likelihood of interference owing to limited coordination among users. In this paper, we address the problem of flexible spectrum sharing where a wideband single carrier modulated signal is spectrally overlapped by unknown narrowband interference (NBI and where a cyclic Wiener filter is utilized for nonparametric NBI suppression at the receiver. The pulse shape design for the wideband signal is investigated to improve the NBI suppression capability of cyclic Wiener filtering. Specifically, two pulse shaping schemes, which outperform existing raised cosine pulse shaping schemes even for the same amount of excess bandwidth, are proposed. Based on computer simulation, the interference suppression capability of cyclic Wiener filtering is evaluated for both the proposed and existing pulse shaping schemes under several interference conditions and over both AWGN and Rayleigh fading channels.

  18. Performance and limitations of quasi-phase matching semiconductor waveguides with picosecond pulses

    Science.gov (United States)

    Wagner, Sean J.; Kumar, S. Chaitanya; Kokabee, Omid; Holmes, Barry M.; Younis, Usman; Ebrahim Zadeh, Majid; Hutchings, David C.; Helmy, Amr S.; Aitchison, J. Stewart

    2010-06-01

    Quasi-phase matched (QPM) second-order nonlinear optical processes in compound semiconductors are attractive for frequency conversion because of their large nonlinear susceptibilities and their mature fabrication processes that permit monolithic integration with pump lasers and other optical elements. Using quantum well intermixing (QWI), we have fabricated domain-disordered QPM (DD-QPM) waveguides in GaAs/AlGaAs superlattices and have previously demonstrated continuous-wave (CW) Type-I second-harmonic generation (SHG) and pulsed Type-II SHG. CW experiments were complicated by Fabry-Perot resonances and thermal bistability. Experiments using a 2-ps pulsed system were affected by third-order nonlinear effects, group-velocity mismatch (GVM), and poor spectral overlap with the conversion bandwidth. A better evaluation of the conversion efficiency may, however, be determined by using longer pulses in order to avoid these complications. By this, the effective CW conversion efficiency and χ(2) modulation can be ascertained. In this paper, we demonstrate SHG in DD-QPM waveguides with reduced parasitic effects by using 20 ps pulses. The waveguide structure consisted of a core layer of GaAs/Al0.85Ga0.15As superlattice into which QPM gratings with a period of 3.8 μm were formed using QWI by As2+ ion implantation. For a Type-I phase matching wavelength of 1583.4 nm, average second-harmonic (SH) powers produced were as high as 2.5 μW for 2 ps pulses and 3.5 μW for 20-ps pulses. At low input powers, the SHG average power conversion efficiency of the 2-ps system was more than 10 times larger than the 20 ps system. As power was increased, the SH power saturated and conversion efficiency decreased to nearly equal to the 20-ps system which remained consistent over the same power range. This is attributed to a reduction in third-order nonlinear effects, a smaller pulse spectral width that overlaps better with the conversion bandwidth, and less pulse walkoff for the 20-ps pulses

  19. Development of small solid rocket boosters for the ILR-33 sounding rocket

    Science.gov (United States)

    Nowakowski, Pawel; Okninski, Adam; Pakosz, Michal; Cieslinski, Dawid; Bartkowiak, Bartosz; Wolanski, Piotr

    2017-09-01

    This paper gives an overview of the development of a 6000 Newton-class solid rocket motor for suborbital applications. The design configuration and results of interior ballistics calculations are given. The initial use of the motor as the main propulsion system of the H1 experimental in-flight test platform, within the Polish Small Sounding Rocket Program, is presented. Comparisons of theoretical and experimental performance are shown. Both on-ground and in-flight tests are discussed. A novel composite-case manufacturing technology, which enabled to reach high propellant mass fractions, was validated and significant cost-reductions were achieved. This paper focuses on the process of adapting the design for use as the booster stage of the ILR-33 sounding rocket, under development at the Institute of Aviation in Warsaw, Poland. Parallel use of two of the flight-proven rocket motors along with the main stage is planned. The process of adapting the rocket motor for booster application consists of stage integration, aerothermodynamics and reliability analyses. The separation mechanism and environmental impact are also discussed within this paper. Detailed performance analysis with focus on propellant grain geometry is provided. The evolution of the design since the first flights of the H1 rocket is covered and modifications of the manufacturing process are described. Issues of simultaneous ignition of two motors and their non-identical performance are discussed. Further applications and potential for future development are outlined. The presented results are based on the initial work done by the Rocketry Group of the Warsaw University of Technology Students' Space Association. The continuation of the Polish Small Sounding Rocket Program on a larger scale at the Institute of Aviation proves the value of the outcomes of the initial educational project.

  20. Liquid rocket engine injectors

    Science.gov (United States)

    Gill, G. S.; Nurick, W. H.

    1976-01-01

    The injector in a liquid rocket engine atomizes and mixes the fuel with the oxidizer to produce efficient and stable combustion that will provide the required thrust without endangering hardware durability. Injectors usually take the form of a perforated disk at the head of the rocket engine combustion chamber, and have varied from a few inches to more than a yard in diameter. This monograph treats specifically bipropellant injectors, emphasis being placed on the liquid/liquid and liquid/gas injectors that have been developed for and used in flight-proven engines. The information provided has limited application to monopropellant injectors and gas/gas propellant systems. Critical problems that may arise during injector development and the approaches that lead to successful design are discussed.

  1. Liquid Rocket Engine Testing

    Science.gov (United States)

    2016-10-21

    booster rocket engines • 6000-10000 psia capabilities – Can use gaseous nitrogen, helium, or hydrogen to pressurize propellant tanks 9Distribution A...Approved for Public Release; Distribution Unlimited. PA Clearance 16493 Simplified Test Stand Layout Oxidizer  TankFuel  Tank High  Pressure   Gas (GN2...requires large, complex facilities to deliver propellant at the proper pressure , temperature, and flow rates • The enormous energies involved

  2. Solid propellant rocket motor

    Science.gov (United States)

    Dowler, W. L.; Shafer, J. I.; Behm, J. W.; Strand, L. D. (Inventor)

    1973-01-01

    The characteristics of a solid propellant rocket engine with a controlled rate of thrust buildup to a desired thrust level are discussed. The engine uses a regressive burning controlled flow solid propellant igniter and a progressive burning main solid propellant charge. The igniter is capable of operating in a vacuum and sustains the burning of the propellant below its normal combustion limit until the burning propellant surface and combustion chamber pressure have increased sufficiently to provide a stable chamber pressure.

  3. Analytical performances of laser-induced micro-plasma of Al samples with single and double ultrashort pulses in air and with Ar-jet: A comparative study

    Energy Technology Data Exchange (ETDEWEB)

    Semerok, A., E-mail: alexandre.semerok@cea.fr [CEA Saclay, DEN/DPC/SEARS/LISL, 91191 Gif-sur-Yvette (France); Dutouquet, C. [CEA Saclay, DEN/DPC/SEARS/LISL, 91191 Gif-sur-Yvette (France); INERIS/DRC/CARA/NOVA, F-60550 Verneuil En Halatte (France)

    2014-09-01

    Ultrashort pulse laser microablation coupled with optical emission spectroscopy was under study to obtain several micro-LIBS analytical features (shot-to-shot reproducibility, spectral line intensity and lifetime, calibration curves, detection limits). Laser microablation of Al matrix samples with known Cu- and Mg-concentrations was performed by single and double pulses of 50 fs and 1 ps pulse duration in air and with Ar-jet. The micro-LIBS analytical features obtained under different experimental conditions were characterized and compared. The highest shot-to-shot reproducibility and gain in plasma spectral line intensity were obtained with double pulses with Ar-jet for both 50 fs and 1 ps pulse durations. The best calibration curves were obtained with 1 ps pulse duration with Ar-jet. Micro-LIBS with ultrashort double pulses may find its effective application for surface elemental microcartography. - Highlights: • Analytical performances of micro-LIBS with ultrashort double pulses were studied. • The maximal line intensity gain of 20 was obtained with double pulses and Ar-jet. • LIBS gain was obtained without additional ablation of a sample by the second pulse. • LIBS properties were almost the same for both 50 fs and 1 ps pulses. • The micro-LIBS detection limit was around 35 ppm.

  4. Effect of direct current and pulse plating on the EDM performance of copper-zirconium diboride composites

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Direct current and pulse plating of copper-zirconium diboride (ZrB2) composites were studied and the effects of current density (DC) and pulse duty cycle (PC) on the EDM performance of the composites were investigated. With increasing current density, the effect of grain refinement on the electro-discharge machining (EDM) performance of the composites compensates that of the decrease of ZrB2 content in the composites, which improves the spark-resistance of the material. Under the same average current density and other experiment conditions, a lower duty cycle yields better EDM performance probably because more ZrB2 particles are incorporated in the composites in this condition. However, at a still lower duty cycle (10%), the particle agglomeration and the microcracks of the copper matrix occur, which considerably deteriorate the spark-resistance of the composites.

  5. Mechanical and Combustion Performance of Multi-Walled Carbon Nanotubes as an Additive to Paraffin-Based Solid Fuels for Hybrid Rockets

    Science.gov (United States)

    Larson, Daniel B.; Boyer, Eric; Wachs, Trevor; Kuo, Kenneth, K.; Koo, Joseph H.; Story, George

    2012-01-01

    Paraffin-based solid fuels for hybrid rocket motor applications are recognized as a fastburning alternative to other fuel binders such as HTPB, but efforts to further improve the burning rate and mechanical properties of paraffin are still necessary. One approach that is considered in this study is to use multi-walled carbon nanotubes (MWNT) as an additive to paraffin wax. Carbon nanotubes provide increased electrical and thermal conductivity to the solid-fuel grains to which they are added, which can improve the mass burning rate. Furthermore, the addition of ultra-fine aluminum particles to the paraffin/MWNT fuel grains can enhance regression rate of the solid fuel and the density impulse of the hybrid rocket. The multi-walled carbon nanotubes also present the possibility of greatly improving the mechanical properties (e.g., tensile strength) of the paraffin-based solid-fuel grains. For casting these solid-fuel grains, various percentages of MWNT and aluminum particles will be added to the paraffin wax. Previous work has been published about the dispersion and mixing of carbon nanotubes.1 Another manufacturing method has been used for mixing the MWNT with a phenolic resin for ablative applications, and the manufacturing and mixing processes are well-documented in the literature.2 The cost of MWNT is a small fraction of single-walled nanotubes. This is a scale-up advantage as future applications and projects will require low cost additives to maintain cost effectiveness. Testing of the solid-fuel grains will be conducted in several steps. Dog bone samples will be cast and prepared for tensile testing. The fuel samples will also be analyzed using thermogravimetric analysis and a high-resolution scanning electron microscope (SEM). The SEM will allow for examination of the solid fuel grain for uniformity and consistency. The paraffin-based fuel grains will also be tested using two hybrid rocket test motors located at the Pennsylvania State University s High Pressure

  6. Additive Manufacturing for Affordable Rocket Engines

    Science.gov (United States)

    West, Brian; Robertson, Elizabeth; Osborne, Robin; Calvert, Marty

    2016-01-01

    Additive manufacturing (also known as 3D printing) technology has the potential to drastically reduce costs and lead times associated with the development of complex liquid rocket engine systems. NASA is using 3D printing to manufacture rocket engine components including augmented spark igniters, injectors, turbopumps, and valves. NASA is advancing the process to certify these components for flight. Success Story: MSFC has been developing rocket 3D-printing technology using the Selective Laser Melting (SLM) process. Over the last several years, NASA has built and tested several injectors and combustion chambers. Recently, MSFC has 3D printed an augmented spark igniter for potential use the RS-25 engines that will be used on the Space Launch System. The new design is expected to reduce the cost of the igniter by a factor of four. MSFC has also 3D printed and tested a liquid hydrogen turbopump for potential use on an Upper Stage Engine. Additive manufacturing of the turbopump resulted in a 45% part count reduction. To understanding how the 3D printed parts perform and to certify them for flight, MSFC built a breadboard liquid rocket engine using additive manufactured components including injectors, turbomachinery, and valves. The liquid rocket engine was tested seven times in 2016 using liquid oxygen and liquid hydrogen. In addition to exposing the hardware to harsh environments, engineers learned to design for the new manufacturing technique, taking advantage of its capabilities and gaining awareness of its limitations. Benefit: The 3D-printing technology promises reduced cost and schedule for rocket engines. Cost is a function of complexity, and the most complicated features provide the largest opportunities for cost reductions. This is especially true where brazes or welds can be eliminated. The drastic reduction in part count achievable with 3D printing creates a waterfall effect that reduces the number of processes and drawings, decreases the amount of touch

  7. Performance of Variable Duration STUD Pulses with Fixed Peal Intensity and their Compliments

    Science.gov (United States)

    Hüller, Stefan; Afeyan, Bedros

    2015-11-01

    The simplest approach to STUD pulse implementation, given the requisite bandwidth of the laser is to keep the peak spike intensities fixed while modulating the lasers on and off on a 1-10 ps time scale. To what extent spatial scrambling is required in this case is compared to cases where the peak spike intensity varies with the duty cycle at fixed pulse width, to preserve the energy of the overall laser pulse. We compare RPP/CPP, SSD and STUD pulses at fixed energy with both variable pulse width and fixed peak intensity configurations and vice versa. This allows us to highlight the effects of speckle statistics, memory accumulation and pump depletion in setting gain saturation levels from the ideal democratized, incoherent sums of small growth spurts equally from all regions of the plasma, vs localized and highly nonlinear growth and re-amplification due to the unchanging or much too slowly changing nature of the illumination strategy, such as RPP/CPP or SSD. Work supported by the DOE NNSA-OFES Joint Program on HEDLP.

  8. Blowing momentum and duty cycle effect on aerodynamic performance of flap by pulsed blowing

    Science.gov (United States)

    Zhou, Ping; Wang, Yankui; Wang, Jinjun; Sha, Yongxiang

    2017-04-01

    Control surface, which is often located in the trailing edge of wings, is important in the attitude control of an aircraft. However, the efficiency of the control surface declines severely under the high deflect angle of the control surface because of the flow separation. To improve the efficiency of control surface, this study discusses a flow-control technique aimed at suppressing the flow separation by pulsed blowing at the leading edge of the control surface. Results indicated that flow separation over the control surface can be suppressed by pulsed blowing, and the maximum average lift coefficient of the control surface can be 95% times higher than that of without blowing when average blowing momentum coefficient is 0.03 relative to that of without blowing. Finally, this study shows that the average blowing momentum coefficient and non-dimensional frequency of pulsed blowing are two of the key parameters of the pulsed blowing control technique. Otherwise, duty cycle also has influence on the effect of pulsed blowing. Numerical simulation is used in this study.

  9. 3D flash lidar performance in flight testing on the Morpheus autonomous, rocket-propelled lander to a lunar-like hazard field

    Science.gov (United States)

    Roback, Vincent E.; Amzajerdian, Farzin; Bulyshev, Alexander E.; Brewster, Paul F.; Barnes, Bruce W.

    2016-05-01

    For the first time, a 3-D imaging Flash Lidar instrument has been used in flight to scan a lunar-like hazard field, build a 3-D Digital Elevation Map (DEM), identify a safe landing site, and, in concert with an experimental Guidance, Navigation, and Control system, help to guide the Morpheus autonomous, rocket-propelled, free-flying lander to that safe site on the hazard field. The flight tests served as the TRL 6 demo of the Autonomous Precision Landing and Hazard Detection and Avoidance Technology (ALHAT) system and included launch from NASA-Kennedy, a lunar-like descent trajectory from an altitude of 250m, and landing on a lunar-like hazard field of rocks, craters, hazardous slopes, and safe sites 400m down-range. The ALHAT project developed a system capable of enabling safe, precise crewed or robotic landings in challenging terrain on planetary bodies under any ambient lighting conditions. The Flash Lidar is a second generation, compact, real-time, air-cooled instrument. Based upon extensive on-ground characterization at flight ranges, the Flash Lidar was shown to be capable of imaging hazards from a slant range of 1 km with an 8 cm range precision and a range accuracy better than 35 cm, both at 1-σ. The Flash Lidar identified landing hazards as small as 30 cm from the maximum slant range which Morpheus could achieve (450 m); however, under certain wind conditions it was susceptible to scintillation arising from air heated by the rocket engine and to pre-triggering on a dust cloud created during launch and transported down-range by wind.

  10. 3-D Flash Lidar Performance in Flight Testing on the Morpheus Autonomous, Rocket-Propelled Lander to a Lunar-Like Hazard Field

    Science.gov (United States)

    Roback, Vincent E.; Amzajerdian, Farzin; Bulyshev, Alexander E.; Brewster, Paul F.; Barnes, Bruce W.

    2016-01-01

    For the first time, a 3-D imaging Flash Lidar instrument has been used in flight to scan a lunar-like hazard field, build a 3-D Digital Elevation Map (DEM), identify a safe landing site, and, in concert with an experimental Guidance, Navigation, and Control (GN&C) system, help to guide the Morpheus autonomous, rocket-propelled, free-flying lander to that safe site on the hazard field. The flight tests served as the TRL 6 demo of the Autonomous Precision Landing and Hazard Detection and Avoidance Technology (ALHAT) system and included launch from NASA-Kennedy, a lunar-like descent trajectory from an altitude of 250m, and landing on a lunar-like hazard field of rocks, craters, hazardous slopes, and safe sites 400m down-range. The ALHAT project developed a system capable of enabling safe, precise crewed or robotic landings in challenging terrain on planetary bodies under any ambient lighting conditions. The Flash Lidar is a second generation, compact, real-time, air-cooled instrument. Based upon extensive on-ground characterization at flight ranges, the Flash Lidar was shown to be capable of imaging hazards from a slant range of 1 km with an 8 cm range precision and a range accuracy better than 35 cm, both at 1-delta. The Flash Lidar identified landing hazards as small as 30 cm from the maximum slant range which Morpheus could achieve (450 m); however, under certain wind conditions it was susceptible to scintillation arising from air heated by the rocket engine and to pre-triggering on a dust cloud created during launch and transported down-range by wind.

  11. Pulse versus continuous peracetic acid applications: Effects on rainbow trout performance, biofilm formation and water quality

    DEFF Research Database (Denmark)

    Liu, Dibo; Straus, David L.; Pedersen, Lars-Flemming

    2017-01-01

    in triplicate flow-through tanks stocked with rainbow trout. The gentler and shorter water cortisol increase measured along twice-per-week pulse applications of 1 mg L−1 PAA indicated a progressive adaptation of fish. In contrast, the continuous application of 0.2 mg L−1 PAA caused no stress to fish....... Meanwhile, no mortality and no impact on growth or innate cellular immunity were observed. The pulse applications restricted biofilm formation, and partially inhibited nitrification. Additionally, the highest oxygen concentration and stable pH were observed. In contrast, the continuous application promoted...... biofilm formation, and caused a pH increase and intermediate oxygen concentration. The contrast was probably due to different susceptibility of microbes to PAA-induced oxidative stress. To summarize, pulse PAA applications cause minor stress in fish, but have advantages over continuous application...

  12. Performance of commercial off-the-shelf microelectromechanical systems sensors in a pulsed reactor environment

    Energy Technology Data Exchange (ETDEWEB)

    Hobert, Keith Edwin [Los Alamos National Laboratory; Heger, Arlen S [Los Alamos National Laboratory; Mccready, Steven S [Los Alamos National Laboratory

    2010-07-15

    Prompted by the unexpected failure of piezoresistive sensors in both an elevated gamma-ray environment and reactor core pulse tests, we initiated radiation testing of several MEMS piezoresistive accelerometers and pressure transducers to ascertain their radiation hardness. Some commercial off-the-shelf sensors are found to be viable options for use in a high-energy pulsed reactor, but others suffer severe degradation and even catastrophic failure. Although researchers are promoting the use of MEMS devices in radiation-harsh environment, we nevertheless find assurance testing necessary.

  13. Experimental Study of Propulsion Performance by Single-Pulse Rotating Detonation with Gaseous Fuels-Oxygen Mixtures

    Science.gov (United States)

    Toshimitsu, Kazuhiko; Hara, Kosei; Mikajiri, Shuuto; Takiguchi, Naoki

    2016-12-01

    A rotating detonation engine (RDE) is one of candidates of aerospace engines for supersonic cruse, which is better for propulsion system than a pulse detonation engine (PDE) from the view of continuous thrust and simple structure. The propulsion performance of a proto-type RDE and a PDE by single pulse explosion with methane-oxygen is investigated. Furthermore, the performance of the RDE with acetylene-oxygen gas mixtures is investigated. Its impulse is estimated through ballistic pendulum method with maximum displacement and damping ratio. The comparison of specific impulses of the mixture gases at atmospheric pressure is shown. The specific impulses of the RDE and the PDE are almost same with methane-oxygen gas. Furthermore, the fuel-base specific impulse of the RDE with acetylene-oxygen gas is about over twice as large as one of methane-oxygen, and its maximum specific impulse is 1100 seconds.

  14. Investigating the performances of a 1 MV high pulsed power linear transformer driver: from beam dynamics to x radiation

    Science.gov (United States)

    Maisonny, R.; Ribière, M.; Toury, M.; Plewa, J. M.; Caron, M.; Auriel, G.; d'Almeida, T.

    2016-12-01

    The performance of a 1 MV pulsed high-power linear transformer driver accelerator were extensively investigated based on a numerical approach which utilizes both electromagnetic and Monte Carlo simulations. Particle-in-cell calculations were employed to examine the beam dynamics throughout the magnetically insulated transmission line which governs the coupling between the generator and the electron diode. Based on the information provided by the study of the beam dynamics, and using Monte Carlo methods, the main properties of the resulting x radiation were predicted. Good agreement was found between these simulations and experimental results. This work provides a detailed understanding of mechanisms affecting the performances of this type of high current, high-voltage pulsed accelerator, which are very promising for a growing number of applications.

  15. The 2003 Goddard Rocket Replica Project: A Reconstruction of the World's First Functional Liquid Rocket System

    Science.gov (United States)

    Farr, R. A.; Elam, S. K.; Hicks, G. D.; Sanders, T. M.; London, J. R.; Mayne, A. W.; Christensen, D. L.

    2003-01-01

    As a part of NASA s 2003 Centennial of Flight celebration, engineers and technicians at Marshall Space Flight Center (MSFC), Huntsville, Alabama, in cooperation with the Alabama-Mississippi AIAA Section, have reconstructed historically accurate, functional replicas of Dr. Robert H. Goddard s 1926 first liquid- fuel rocket. The purposes of this project were to clearly understand, recreate, and document the mechanisms and workings of the 1926 rocket for exhibit and educational use, creating a vital resource for researchers studying the evolution of liquid rocketry for years to come. The MSFC team s reverse engineering activity has created detailed engineering-quality drawings and specifications describing the original rocket and how it was built, tested, and operated. Static hot-fire tests, as well as flight demonstrations, have further defined and quantified the actual performance and engineering actual performance and engineering challenges of this major segment in early aerospace history.

  16. Nuclear Thermal Rocket Propulsion Systems

    Science.gov (United States)

    2007-11-02

    NUCLEAR THERMAL ROCKET PROPULSION SYSTEMS, IAA WHITE PAPER PARIS, FRANCE, MARCH 2005 Lt Col Timothy J. Lawrence U.S. Air Force Academy...YYYY) 18-03-2005 2. REPORT TYPE White Paper 3. DATES COVERED (From - To) 18 Mar 2005 4. TITLE AND SUBTITLE NUCLEAR THERMAL ROCKET PROPULSION...reduce radiation exposure, is to have a high energy system like a nuclear thermal rocket that can get the payload to the destination in the fastest

  17. Improved performance of Li-ion cells under pulsed load using double-layer capacitors in a hybrid circuit mode

    Energy Technology Data Exchange (ETDEWEB)

    ROTH,EMANUEL P.; NAGASUBRAMANIAN,GANESAN

    2000-02-07

    Electrical characteristics of hybrid power sources consisting of Li-ion cells and double-layer capacitors were studied at 25 C and {minus}20 C. The cells were initially evaluated for pulse performance and then measured in hybrid modes of operation where they were coupled with the high-power capacitors. Cells manufactured by Panasonic measured at 25 C delivered full capacities of 0.76 Ah for pulses up to 3A and cells from A and T delivered full capacities of 0.73 Ah for pulses up to 4A. Measured cell resistances were 0.15 ohms and 0.12 ohms, respectively. These measurements were repeated at {minus}20 C. Direct coupling of the cells and capacitors (coupled hybrid) using 10F Panasonic capacitors in a 8F series/parallel combination extended the full capacity pulse limits (3.0V threshold) to 5.6A for the Panasonic cells and to 9A for the A and T cells. A similar arrangement using 100F capacitors from Elna in a 60F combination increased the Panasonic cell limit to 10 A. Operation in an uncoupled hybrid mode using uncoupled cell/capacitor discharge allowed fill cell capacity usage at 25 C up to the capacitor discharge limit and showed a factor of 5 improvement in delivered capacity at {minus}20 C.

  18. Distributed Rocket Engine Testing Health Monitoring System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The on-ground and Distributed Rocket Engine Testing Health Monitoring System (DiRETHMS) provides a system architecture and software tools for performing diagnostics...

  19. Performance of coherent and noncoherent RAKE receivers with convolutional coding ricean fading and pulse-noise interference

    OpenAIRE

    Kowalske, Kyle E.

    2004-01-01

    Approved for public release, distribution is unlimited The performance of coherent and noncoherent RAKE receivers over a fading channel in the presence of pulse-noise interference and additive white Gaussian noise is analyzed. Coherent RAKE receivers require a pilot tone for coherent demodulation. Using a first order phase-lock-loop to recover a pilot tone with additive white Gaussian noise causes phase distortions at the phase-lock-loop output, which produce an irreducible phase noise err...

  20. Rocket Assembly and Checkout Facility

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Integrates, tests, and calibrates scientific instruments flown on sounding rocket payloads. The scientific instruments are assembled on an optical bench;...

  1. Pulse Power Performance of the Cygnus 1 and 2 Radiographic Sources

    Science.gov (United States)

    2013-06-01

    The Cygnus 1 machine was constructed and fielded at the Los Alamos National Laboratory to undergo pulsed power component and reliability testing and for...result of the cooperative effort of Titan PSD, Sandia National Laboratory, Los Alamos National Laboratory , and Bechtel Nevada.

  2. Effects of hyperinflation on the oxygen pulse as a marker of cardiac performance in COPD.

    Science.gov (United States)

    Vassaux, C; Torre-Bouscoulet, L; Zeineldine, S; Cortopassi, F; Paz-Díaz, H; Celli, B R; Pinto-Plata, V M

    2008-11-01

    A decreased inspiratory capacity (IC)/total lung capacity (TLC) ratio is associated with dynamic hyperinflation and decreased exercise capacity. The present authors hypothesised that static (low IC/TLC) and dynamic hyperinflation impair cardiac function as assessed by oxygen pulse at rest and during cardiopulmonary exercise testing (CPET). Lung function, body mass index, hand grip strength and CPET parameters were measured (oxygen uptake (mL x kg(-1) x min(-1)) and oxygen pulse (mL x beat(-1))) in 87 chronic obstructive pulmonary disease (COPD) patients (American Thoracic Society/European Respiratory Society/Global Initiative for Chronic Obstructive Lung Disease stage 3-4) and 46 controls. The patients were divided into those with IC/TLC > 25% or 25% and controls. During CPET, the oxygen pulse was lower at iso-work in patients with IC/TLC 25%. Resting hyperinflation (inspiratory capacity/total lung capacity) is associated with lower oxygen pulse, peak exercise inspiratory capacity/total lung capacity and exercise capacity in patients with severe chronic obstructive pulmonary disease. The present results support an interaction between hyperinflation and decreased cardiac function that may contribute to exercise limitation in these patients.

  3. Design and performance of the pulsed positron beam at Chalmers University of Technology

    Science.gov (United States)

    Mileshina, L.; Nordlund, A.

    2009-09-01

    A slow monoenergetic pulsed positron beam at Chalmers University of Technology has been built. The system consists mainly of chopper, buncher and accelerator. The achieved positron energy range is in range between 230 eV and 15 keV. The FWHM of the beam resolution function is around 700 ps. The beam intensity is around 103 cps.

  4. Pulse versus continuous peracetic acid applications: effects on Rainbow trout performance, biofilm formation and water quality

    Science.gov (United States)

    Peracetic acid (PAA) products are being introduced to aquaculture as sustainable disinfectants. Two strategies are used to apply PAA: short term high dose (1-2 mg L-1 PAA) periodic pulse applications or continuous low dose (< 0.2 mg L-1 PAA) applications. In the present study, these strategies and a...

  5. Note: radio frequency inductance-capacitance band-stop filter circuit to perform contactless conductivity measurements in pulsed magnetic fields.

    Science.gov (United States)

    Altarawneh, M M

    2012-09-01

    We present a new technique to perform radio frequency (rf) contactless conductivity measurements in pulsed magnetic fields to probe different ground states in condensed matter physics. The new method utilizes a simple analog band-stop filter circuit implemented in a radio frequency transmission setup to perform contactless conductivity measurements. The new method is more sensitive than the other methods (e.g., the tunnel diode oscillator and the proximity detector oscillator) due to more sensitive dependence of the circuit resonance frequency on the tank circuit inductance (not the transmission line). More important, the new method is more robust than other methods when used to perform measurements in very high magnetic fields, works for a wide range of temperatures (i.e., 300 K-1.4 K) and is less sensitive to noise and mechanical vibrations during pulse magnet operation. The new technique was successfully applied to measure the Shubnikov-de Haas effect in Bi(2)Se(3) in pulsed magnetic fields of up to 60 T.

  6. Rocket + Science = Dialogue

    Science.gov (United States)

    Morris,Bruce; Sullivan, Greg; Burkey, Martin

    2010-01-01

    It's a cliche that rocket engineers and space scientists don t see eye-to-eye. That goes double for rocket engineers working on human spaceflight and scientists working on space telescopes and planetary probes. They work fundamentally different problems but often feel that they are competing for the same pot of money. Put the two groups together for a weekend, and the results could be unscientific or perhaps combustible. Fortunately, that wasn't the case when NASA put heavy lift launch vehicle designers together with astronomers and planetary scientists for two weekend workshops in 2008. The goal was to bring the top people from both groups together to see how the mass and volume capabilities of NASA's Ares V heavy lift launch vehicle could benefit the science community. Ares V is part of NASA's Constellation Program for resuming human exploration beyond low Earth orbit, starting with missions to the Moon. In the current mission scenario, Ares V launches a lunar lander into Earth orbit. A smaller Ares I rocket launches the Orion crew vehicle with up to four astronauts. Orion docks with the lander, attached to the Ares V Earth departure stage. The stage fires its engine to send the mated spacecraft to the Moon. Standing 360 feet high and weighing 7.4 million pounds, NASA's new heavy lifter will be bigger than the 1960s-era Saturn V. It can launch almost 60 percent more payload to translunar insertion together with the Ares I and 35 percent more mass to low Earth orbit than the Saturn V. This super-sized capability is, in short, designed to send more people to more places to do more things than the six Apollo missions.

  7. Rocket and Laboratory Studies in Astronomy

    Science.gov (United States)

    Feldman, Paul D.

    2001-01-01

    This is the final report for NASA Grant NAG5-5122 and covers the period from March 1, 1997 to February 28, 2001. This grant was a continuation of a program in rocket and laboratory studies in ultraviolet astronomy that was supported by NASA grant NAG5-619. As of March 1, 2001, this program is continuing under grant NAG5-5315. During the period of the grant, annual status reports have been submitted detailing the scientific achievements and current objectives of each report period. These will not be repeated here. Among the highlights of the program are four successful rocket launches including participation in the campaign to study comet Hale-Bopp in April 1997. We have continued our emphasis on long-slit spectroscopy of extended sources in the shorter wavelength far-ultraviolet, necessitating the development of evacuated telescope/spectrograph payloads. Finally, we also note the use of our ultraviolet calibration facilities in support of other sounding rocket investigators and for other space missions such as the Far Ultraviolet Spectroscopic Explorer. We include a list of the sounding rocket launches performed under NASA sponsorship during this period, a list of Ph.D. degrees awarded to students who worked in this program, and a summary bibliography of publications between 1997 and 2001.

  8. In-flight performance of pulse processing system of the ASTRO-H soft x-ray spectrometer

    Science.gov (United States)

    Ishisaki, Yoshitaka; Yamada, Shinya; Seta, Hiromi; Tashiro, Makoto S.; Takeda, Sawako; Terada, Yukikatsu; Kato, Yuka; Tsujimoto, Masahiro; Koyama, Shu; MItsuda, Kazuhisa; Sawada, Makoto; Boyce, Kevin R.; Chiao, Meng P.; Watanabe, Tomomi; Leutenegger, Maurice A.; Eckart, Megan E.; Porter, F. Scott; Kilbourne, Caroline A.; Kelley, Richard L.

    2016-07-01

    We summarize results of the initial in-orbit performance of the pulse shape processor (PSP) of the soft x-ray spectrometer instrument onboard ASTRO-H (Hitomi). Event formats, kind of telemetry, and the pulse processing parameters are described, and the parameter settings in orbit are listed. PSP was powered-on two days after launch, and the event threshold was lowered in orbit. PSP worked fine in orbit, and there were no memory error nor SpaceWire communication error until the break-up of spacecraft. Time assignment, electrical crosstalk, and the event screening criteria are studied. It is confirmed that the event processing rate at 100% CPU load is 200 c/s/array, compliant with the requirement on PSP.

  9. Flow separation in rocket nozzles under high altitude condition

    Science.gov (United States)

    Stark, R.; Génin, C.

    2017-01-01

    The knowledge of flow separation in rocket nozzles is crucial for rocket engine design and optimum performance. Typically, flow separation is studied under sea-level conditions. However, this disregards the change of the ambient density during ascent of a launcher. The ambient flow properties are an important factor concerning the design of altitude-adaptive rocket nozzles like the dual bell nozzle. For this reason an experimental study was carried out to study the influence of the ambient density on flow separation within conventional nozzles.

  10. Theoretical performance of liquid ammonia, hydrazine and mixture of liquid ammonia and hydrazine as fuels with liquid oxygen biflouride as oxidant for rocket engines : I-mixture of liquid ammonia and hydrazine

    Science.gov (United States)

    Huff, Vearl N; Gordon, Sanford

    1952-01-01

    Theoretical performance for mixture of 36.3 percent liquid ammonia and 63.7 percent hydrazine with liquid oxygen bifluoride as rocket propellant was calculated on assumption of equilibrium composition during expansion for a wide range of fuel-oxidant and expansios ratios. Parameters included were specific impulse, combustion-chamber temperature, nozzle exit temperature, composition mean molecular weight, characteristic velocity, coefficient of thrust and ratio of nozzle-exit area to throat area. For chamber pressure of 300 pounds per square inch absolute and expansion to 1 atmosphere, maximum specific impulse was 295.8 pound-seconds per pound. Five percent by weight of water in the hydrazine lowered specific impulse from about one to three units over a wide range of weight-percent fuel.

  11. Aerodynamic performance enhancement of a flying wing using nanosecond pulsed DBD plasma actuator

    Directory of Open Access Journals (Sweden)

    Han Menghu

    2015-04-01

    Full Text Available Experimental investigation of aerodynamic control on a 35° swept flying wing by means of nanosecond dielectric barrier discharge (NS-DBD plasma was carried out at subsonic flow speed of 20–40 m/s, corresponding to Reynolds number of 3.1 × 105–6.2 × 105. In control condition, the plasma actuator was installed symmetrically on the leading edge of the wing. Lift coefficient, drag coefficient, lift-to-drag ratio and pitching moment coefficient were tested with and without control for a range of angles of attack. The tested results indicate that an increase of 14.5% in maximum lift coefficient, a decrease of 34.2% in drag coefficient, an increase of 22.4% in maximum lift-to-drag ratio and an increase of 2° at stall angle of attack could be achieved compared with the baseline case. The effects of pulsed frequency, amplitude and chord Reynolds number were also investigated. And the results revealed that control efficiency demonstrated strong dependence on pulsed frequency. Moreover, the results of pitching moment coefficient indicated that the breakdown of leading edge vortices could be delayed by plasma actuator at low pulsed frequencies.

  12. Recent Performance and Ignition Tests of the pulsed SNS H- Source for 1-MW Neutron Production

    Energy Technology Data Exchange (ETDEWEB)

    Stockli, Martin P [ORNL; Han, Baoxi [ORNL; Murray, Jr, S N [ORNL; Pennisi, Terry R [ORNL; Piller, Chip [ORNL; Santana, Manuel [ORNL; Welton, Robert F [ORNL

    2015-01-01

    After acquiring several reliable spare targets, SNS ramped the beam power from 850 kW to 1.4 MW, which required an increase in H- beam pulse length from 0.88 to 1.0 ms at 60 Hz. This increase initially produced slow 2-MHz power ramp-ups and, after several weeks of uninterrupted operation, it produced plasma outages every time the pulse length was raised above ~0.95 ms. Similar outages were previously observed towards the end of long service cycles, which were believed to indicate that the breakdown voltage of the high purity hydrogen started to exceed the induced electric fields. In 2011 the RF was reconfigured to start with 10 cycles of 1.96 MHz, which yielded the shortest H- beam rise times and apparently eliminated those plasma outages. The new, pulse-length dependent outages were eliminated by increasing the initial frequency to 1.985 MHz. However, careful frequency studies are unable to justify this frequency. In addition, the paper discusses the issues and solutions for the electron-dump voltage, which starts to sag and become unstable after several weeks of high current operation.

  13. What fuel for a rocket?

    CERN Document Server

    Miranda, E N

    2012-01-01

    Elementary concepts from general physics and thermodynamics have been used to analyze rocket propulsion. Making some reasonable assumptions, an expression for the exit velocity of the gases is found. From that expression one can conclude what are the desired properties for a rocket fuel.

  14. Rocket launchers as passive controllers

    Science.gov (United States)

    Cochran, J. E., Jr.; Gunnels, R. T.; McCutchen, R. K., Jr.

    1981-12-01

    A concept is advanced for using the motion of launchers of a free-flight launcher/rocket system which is caused by random imperfections of the rockets launched from it to reduce the total error caused by the imperfections. This concept is called 'passive launcher control' because no feedback is generated by an active energy source after an error is sensed; only the feedback inherent in the launcher/rocket interaction is used. Relatively simple launcher models with two degrees of freedom, pitch and yaw, were used in conjunction with a more detailed, variable-mass model in a digital simulation code to obtain rocket trajectories with and without thrust misalignment and dynamic imbalance. Angular deviations of rocket velocities and linear deviations of the positions of rocket centers of mass at burnout were computed for cases in which the launcher was allowed to move ('flexible' launcher) and was constrained so that it did not rotate ('rigid' launcher) and ratios of flexible to rigid deviations were determined. Curves of these error ratios versus launcher frequency are presented. These show that a launcher which has a transverse moment of inertia about its pivot point of the same magnitude as that of the centroidal transverse moments of inertia of the rockets launched from it can be tuned to passively reduce the errors caused by rocket imperfections.

  15. Preliminary study on heat load using calorimetric measurement during long-pulse high-performance discharges on EAST

    Science.gov (United States)

    Liu, Y. K.; Hamada, N.; Hanada, K.; Gao, X.; Liu, H. Q.; Yu, Y. W.; Qian, J. P.; Yang, L.; Xu, T. J.; Jie, Y. X.; Yao, Y.; Wang, S. S.; Xu, J. C.; Yang, Z. D.; Li, G. S.; EAST Team

    2017-04-01

    Experimental Advanced Superconducting Tokamak (EAST) aims to demonstrate steady-state advanced high-performance H-mode plasmas with an ITER-like configuration, plasma control and heating schemes. The plasma-facing components in EAST are actively cooled, providing good conditions for researching long-pulse and high-energy discharges. A long-pulse high-performance plasma discharge (#59892 discharge) of up to 103 s with a core electron temperature of up to 4.5 keV was sustained with an injected energy exceeding 0.22 GJ in the 2015–2016 experimental campaign. A calorimetric measurement utilizing the temperature increment of cooling water is carried out to calculate the heat load on the strike point region of the lower divertor during long-pulse discharges in EAST. For the long-pulse and high-energy discharges, the comparison of the measurement results for the heat load measured by divertor Langmuir probes and the calorimetry diagnostic indicates that most of the heat load is delivered to the divertor panels as plasma, not radiation, and charge exchange neutrals. The ratio of the heat load on the strike point region of the lower divertor to the total injected energy is on average 42.5% per discharge with the lower single null divertor configuration. If the radiated energy loss measured by the fast bolometer diagnostic is taken into consideration, the ratio is found to be 61.6%. The experimental results and the analysis of the physics involved in these discharges are reported and discussed.

  16. Development Testing of 1-Newton ADN-Based Rocket Engines

    Science.gov (United States)

    Anflo, K.; Gronland, T.-A.; Bergman, G.; Nedar, R.; Thormählen, P.

    2004-10-01

    With the objective to reduce operational hazards and improve specific and density impulse as compared with hydrazine, the Research and Development (R&D) of a new monopropellant for space applications based on AmmoniumDiNitramide (ADN), was first proposed in 1997. This pioneering work has been described in previous papers1,2,3,4 . From the discussion above, it is clear that cost savings as well as risk reduction are the main drivers to develop a new generation of reduced hazard propellants. However, this alone is not enough to convince a spacecraft builder to choose a new technology. Cost, risk and schedule reduction are good incentives, but a spacecraft supplier will ask for evidence that this new propulsion system meets a number of requirements within the following areas: This paper describes the ongoing effort to develop a storable liquid monopropellant blend, based on AND, and its specific rocket engines. After building and testing more than 20 experimental rocket engines, the first Engineering Model (EM-1) has now accumulated more than 1 hour of firing-time. The results from test firings have validated the design. Specific impulse, combustion stability, blow-down capability and short pulse capability are amongst the requirements that have been demonstrated. The LMP-103x propellant candidate has been stored for more than 1 year and initial material compatibility screening and testing has started. 1. Performance &life 2. Impact on spacecraft design &operation 3. Flight heritage Hereafter, the essential requirements for some of these areas are outlined. These issues are discussed in detail in a previous paper1 . The use of "Commercial Of The Shelf" (COTS) propulsion system components as much as possible is essential to minimize the overall cost, risk and schedule. This leads to the conclusion that the Technology Readiness Level (TRL) 5 has been reached for the thruster and propellant. Furthermore, that the concept of ADN-based propulsion is feasible.

  17. 航天发射场导流槽综合性能评价指标体系研究%Research on Global Performance Design Method of Blast Deflector in Rocket Launch Site

    Institute of Scientific and Technical Information of China (English)

    刘利宏; 张志成; 周旭

    2014-01-01

    导流槽是航天发射场的重要核心设施,作用是排导火箭发动机产生的高温高压燃气射流。基于计算流体动力学原理,利用理论分析、试验研究和数值仿真方法,开展发动机燃气射流在导流槽内部流动特性以及射流噪声传播和辐射特性等火箭发射环境效应问题研究,对导流槽设计中关心的冲击、烧蚀、通畅性以及喷水冷却系统的效率和噪声防护等问题进行评价,初步建立导流槽优化设计综合性能评价指标,为导流槽综合性能设计提供重要的参考依据。%Blast deflector is one of the key infrastructures in the rocket launch site which deflects the high temperature and high pressure jet emitted by the rocket engine .Based on the computational flu-id dynamics theory , theoretical analysis , experimental investigations and numerical simulation were adopted to study the launch environment effects including the flow characteristic of jet engine flame in blast deflector and the disseminated property of jet engine noise .Issues concerning the flow safety and smoothness and the efficiency of spray system in design of blast deflector were evaluated .The performance assessment index of blast deflector was preliminarily set up by multiple analysis methods which may provide reference for the global performance optimization design of the blast deflector .

  18. Peregrine 100-km Sounding Rocket Project

    Science.gov (United States)

    Zilliac, Gregory

    2012-01-01

    The Peregrine Sounding Rocket Program is a joint basic research program of NASA Ames Research Center, NASA Wallops, Stanford University, and the Space Propulsion Group, Inc. (SPG). The goal is to determine the applicability of this technology to a small launch system. The approach is to design, build, and fly a stable, efficient liquefying fuel hybrid rocket vehicle to an altitude of 100 km. The program was kicked off in October of 2006 and has seen considerable progress in the subsequent 18 months. This research group began studying liquifying hybrid rocket fuel technology more than a decade ago. The overall goal of the research was to gain a better understanding of the fundamental physics of the liquid layer entrainment process responsible for the large increase in regression rate observed in these fuels, and to demonstrate the effect of increased regression rate on hybrid rocket motor performance. At the time of this reporting, more than 400 motor tests were conducted with a variety of oxidizers (N2O, GOx, LOx) at ever increasing scales with thrust levels from 5 to over 15,000 pounds (22 N to over 66 kN) in order to move this technology from the laboratory to practical applications. The Peregrine program is the natural next step in this development. A number of small sounding rockets with diameters of 3, 4, and 6 in. (7.6, 10.2, and 15.2 cm) have been flown, but Peregrine at a diameter of 15 in. (38.1 cm) and 14,000-lb (62.3-kN) thrust is by far the largest system ever attempted and will be one of the largest hybrids ever flown. Successful Peregrine flights will set the stage for a wide range of applications of this technology.

  19. Performance study of highly efficient 520 W average power long pulse ceramic Nd:YAG rod laser

    Science.gov (United States)

    Choubey, Ambar; Vishwakarma, S. C.; Ali, Sabir; Jain, R. K.; Upadhyaya, B. N.; Oak, S. M.

    2013-10-01

    We report the performance study of a 2% atomic doped ceramic Nd:YAG rod for long pulse laser operation in the millisecond regime with pulse duration in the range of 0.5-20 ms. A maximum average output power of 520 W with 180 J maximum pulse energy has been achieved with a slope efficiency of 5.4% using a dual rod configuration, which is the highest for typical lamp pumped ceramic Nd:YAG lasers. The laser output characteristics of the ceramic Nd:YAG rod were revealed to be nearly equivalent or superior to those of high-quality single crystal Nd:YAG rod. The laser pump chamber and resonator were designed and optimized to achieve a high efficiency and good beam quality with a beam parameter product of 16 mm mrad (M2˜47). The laser output beam was efficiently coupled through a 400 μm core diameter optical fiber with 90% overall transmission efficiency. This ceramic Nd:YAG laser will be useful for various material processing applications in industry.

  20. Nuclear Rocket Engine Reactor

    CERN Document Server

    Lanin, Anatoly

    2013-01-01

    The development of a nuclear rocket engine reactor (NRER ) is presented in this book. The working capacity of an active zone NRER under mechanical and thermal load, intensive neutron fluxes, high energy generation (up to 30 MBT/l) in a working medium (hydrogen) at temperatures up to 3100 K is displayed. Design principles and bearing capacity of reactors area discussed on the basis of simulation experiments and test data of a prototype reactor. Property data of dense constructional, porous thermal insulating and fuel materials like carbide and uranium carbide compounds in the temperatures interval 300 - 3000 K are presented. Technological aspects of strength and thermal strength resistance of materials are considered. The design procedure of possible emergency processes in the NRER is developed and risks for their origination are evaluated. Prospects of the NRER development for pilotless space devices and piloted interplanetary ships are viewed.

  1. Contribution to the study of propulsive performances of a pulsed detonation engine; Contribution a l'etude des performances d'un moteur a detonation pulsee

    Energy Technology Data Exchange (ETDEWEB)

    Daniau, E.

    2001-12-15

    The works carried out in this study aim at quantifying the propelling efficiency of a pulsed detonation engine (reciprocating jet engine) and to study its aerobic configuration. The study of the propelling efficiency (specific pulse, thrust) has been performed with the C{sub 2}H{sub 4} - O{sub 2} mixture, the use of the H{sub 2}-air mixture being restricted to the aerobic demonstrator. In a first step, an analytical and theoretical study based on previous results has permitted to establish an efficiency model for the ideal case of a filled-up cylindrical combustion chamber, closed at one end and opened at the other end to the ambient atmosphere P{sub a}. The departure from the ideal case has been tackled by diminishing the detonation pressure with respect to P{sub a}. In a second step, several experimental studies (performed on mono-cycle bench) have been carried out to evaluate the influence of i) the presence of air inlets, ii) the partial filling of the chamber, iii) the presence of nozzles, iv) the presence of obstacles close to the ejection section, on the real efficiencies accessible with this type of engine. Specific experimental methods have been implemented and validated (pressure measurement on thrust wall, strioscopy visualisation, pulse measurement by ballistic pendulum) for the obtention of the two main parameters controlling the efficiencies: the specific pulse and the cycle time, this last one determining the maximum possible mass flow rate of reactive mixture or the maximum operation frequency. The realization of a 'real conditions' multi-cycle test bench has permitted to validate some technical solutions (necessity to initiate the detonation of the main H{sub 2}-air mixture using a pre-detonation system based on the highly reacting C{sub 2}H{sub 4}-O{sub 2} mixture) and to observe some specific phenomena of the multi-cycle operation. (J.S.)

  2. Improved Switching Performance Analysis of Space Vector Pulse Width Modulation on Field Programmable Gate Array

    Directory of Open Access Journals (Sweden)

    Nagalingam RAJESWARAN

    2014-02-01

    Full Text Available Nowadays VLSI (Very Large Scale Integration technology is being successfully implemented by using Pulse Width Modulation (PWM in applications like power electronics and drives. The main problems in PWM viz. harmonic distortion and switching speed are overcome by implementing the Space-Vector PWM (SVPWM technique by using the Xilinx tool VHDL (Verilog High Speed Integrated Circuit (VHSIC Hardware Description Language and tested in programmable Integrated Circuits of Field Programmable Gate Array (FPGA. The results are provided along with simulation analysis in terms of hardware utilization and schematic, power report, computing time and usage of memory.

  3. Performance of a reflectometer at continuous wave and pulsed neutron sources

    Energy Technology Data Exchange (ETDEWEB)

    Fitzsimmons, M.R. [Los Alamos National Laboratory, NM (United States)

    1995-12-31

    The Monte-Carlo simulations presented here involve simulations of reflectivity measurements of one sample using a reflectometer of traditional geometry at different neutron sources. The same reflectometer was used in all simulations. Only the characteristics of the neutron source, and the technique used to measure neutron wavelength were changed. In the case of the CW simulation, a monochromating crystal was used to select a nearly monochromatic beam (MB) from the neutron spectrum. In the simulations of the pulse sources, the time needed to traverse a fixed distance was measured, from which neutron wavelength is deduced.

  4. Pulse on Pulse

    DEFF Research Database (Denmark)

    Schmidt, Ulrik; Carlson, Merete

    2012-01-01

    Pulse on Pulse” investigates the relation between signifying processes and non-signifying material dynamism in the installation Pulse Room (2006-) by Mexican Canadian artist Rafael Lozano-Hemmer. In Pulse Room the sense of pulse is ambiguous. Biorhythms are transmitted from the pulsing energy...... and pulsating ‘room’. Hence, the visitors in Pulse Room are invited into a complex scenario that continuously oscillates between various aspects of signification (the light bulbs representing individual lives; the pulse itself as the symbolic ‘rhythm of life’) and instants of pure material processuality...... a multilayered sense of time and space that is central to the sensory experience of Pulse Room as a whole. Pulse Room is, at the very same time, an anthropomorfized archive of a past intimacy and an all-encompassing immersive environment modulating continuously in real space-time....

  5. Computational Analysis for Rocket-Based Combined-Cycle Systems During Rocket-Only Operation

    Science.gov (United States)

    Steffen, C. J., Jr.; Smith, T. D.; Yungster, S.; Keller, D. J.

    2000-01-01

    A series of Reynolds-averaged Navier-Stokes calculations were employed to study the performance of rocket-based combined-cycle systems operating in an all-rocket mode. This parametric series of calculations were executed within a statistical framework, commonly known as design of experiments. The parametric design space included four geometric and two flowfield variables set at three levels each, for a total of 729 possible combinations. A D-optimal design strategy was selected. It required that only 36 separate computational fluid dynamics (CFD) solutions be performed to develop a full response surface model, which quantified the linear, bilinear, and curvilinear effects of the six experimental variables. The axisymmetric, Reynolds-averaged Navier-Stokes simulations were executed with the NPARC v3.0 code. The response used in the statistical analysis was created from Isp efficiency data integrated from the 36 CFD simulations. The influence of turbulence modeling was analyzed by using both one- and two-equation models. Careful attention was also given to quantify the influence of mesh dependence, iterative convergence, and artificial viscosity upon the resulting statistical model. Thirteen statistically significant effects were observed to have an influence on rocket-based combined-cycle nozzle performance. It was apparent that the free-expansion process, directly downstream of the rocket nozzle, can influence the Isp efficiency. Numerical schlieren images and particle traces have been used to further understand the physical phenomena behind several of the statistically significant results.

  6. Oxidizer heat exchangers for rocket engine operation in idle modes

    Science.gov (United States)

    Kanic, P. G.; Kmiec, T. D.

    1987-01-01

    The heat exchanger concept is discussed together with its role in rocket engine operation in idle modes. Two heat exchanger designs (low and high heat transfer) utilizing different approaches to achieve stable oxygen vaporization are presented as well as their performance test results. It is concluded that compact and lightweight heat exchangers can be used in a stable manner under the 'idle' operating conditions expected with the RL10 rocket engine.

  7. Numerical and Experimental Investigation of Hybrid Rocket Motors Transient Behavior

    OpenAIRE

    Barato, Francesco

    2013-01-01

    As the space business is shifting from pure performances to affordability a renewed interest is growing about hybrid rocket propulsion. Hybrid rocket motors are attractive for their inherent advantages like simplicity, reliability, safety and reduced costs. Moreover hybrid motors are easy to throttle and thus they are ideal candidate when soft-landing or energy management capabilities are required. This thesis is mainly involved with a theoretical/numerical study of hybrid transie...

  8. Comparison of Performance Metrics for QPSK and OQPSK Transmission Using Root Raised Cosine and Raised Cosine Pulse shaping Filters for Applications in Mobile Communication

    CERN Document Server

    Chattopadhyay, Sudipta

    2009-01-01

    Quadrature Phase Shift Keying (QPSK) and Offset Quadrature Phase Shift Keying (OQPSK) are two well accepted modulation techniques used in Code Division Multiple Access (CDMA) system. The Pulse Shaping Filters play an important role in digital transmission. The type of Pulse Shaping Filter used, and its behavior would influence the performance of the communication system. This in turn, would have an effect on the performance of the Mobile Communication system, in which the digital communication technique has been employed. In this paper we have presented comparative study of some performance parameters or performance metrics of a digital communication system like, Error Vector Magnitude (EVM), Magnitude Error, Phase Error and Bandwidth Efficiency for a QPSK transmission system. Root Raised Cosine (RRC) and Raised Cosine (RC) Pulse shaping filters have been used for comparison. The measurement results serve as a guideline to the system designer to select the proper pulse shaping filter with the appropriate valu...

  9. Electra: Repetitively Pulsed Angularly Multiplexed KrF Laser System Performance

    Science.gov (United States)

    Wolford, Matthew; Myers, Matthew; Giuliani, John; Sethian, John; Burns, Patrick; Hegeler, Frank; Jaynes, Reginald

    2008-11-01

    As in a full size fusion power plant beam line, Electra is a multistage laser amplifier system. The multistage amplifier system consists of a commercial discharge laser and two doubled sided electron beam pumped amplifiers. Angular multiplexing is used in the optical layout to provide pulse length control and to maximize laser extraction from the amplifiers. Two angularly multiplexed beams have extracted 30 J of KrF laser light with an aperture 8 x 10 cm^2, which is sufficient to extract over 500 J from the main amplifier and models agree. The main amplifier of Electra in oscillator mode has demonstrated single shot and rep-rate laser energies exceeding 700 J with 100 ns pulsewidth at 248 nm with an aperture 29 x 29 cm^2. Continuous operation of the KrF electron beam pumped oscillator has lasted for more than 2.5 hours without failure at 1 Hz and 2.5 Hz. The measured intensity and pulse energy for durations greater than thousand shots are consistent at measurable rep-rates of 1 Hz, 2.5 Hz and 5 Hz.

  10. Use of ns and fs pulse excitation in laser-induced breakdown spectroscopy to improve its analytical performances: A case study on quaternary bronze alloys

    Energy Technology Data Exchange (ETDEWEB)

    Almaviva, Salvatore [ENEA, UTAPRAD, V. E. Fermi 45, 00044 Frascati (Italy); Fantoni, Roberta, E-mail: roberta.fantoni@enea.it [ENEA, UTAPRAD, V. E. Fermi 45, 00044 Frascati (Italy); Caneve, Luisa; Colao, Francesco [ENEA, UTAPRAD, V. E. Fermi 45, 00044 Frascati (Italy); Fornarini, Lucilla [ENEA,UTTAMB, SP Anguillarese 301, Roma (Italy); Santagata, Antonio [CNR-IMIP, UOS Potenza, Zona Industriale, 85050 Tito Scalo (PZ) (Italy); Teghil, Roberto [Università degli Studi della Basilicata, Dipartimento di Scienze, Via dell' Ateneo Lucano 10, 85100 Potenza (Italy)

    2014-09-01

    Analytical performances of Laser Induced Breakdown Spectroscopy (LIBS) resulted not fully satisfactory in some cases such as historical bronzes, therefore, efforts should be focussed on improving ablation efficiency and on better understanding the plasma parameter evolution. To this aim a set of double pulse experiments have been carried out in almost collinear geometry at about 530 nm laser excitation. The first emitting source was either a ns or a fs laser the second a ns one. Data were collected as a function of the interpulse delay, in order to determine the ablation efficiency increase, to study the kinetics of plasma parameters (temperature, electron density) and the decay of atomic and ionic intensities with respect to the optical background. In parallel a previously developed model for laser ablation, ionization and following plasma decay, was implemented, adding a second laser pulse, to analyse the double pulse excitation in the considered geometry, and the time evolution of the same variables was investigated. Model results are able to reproduce the observed experimental trends and support the possibility of improving analytical performances by using the double pulse technique with inter-pulse delays in the entire investigated range. - Highlights: • The Double Pulse LIBS technique is applied to a quaternary metal alloy sample. • Two different Double Pulse LIBS configurations are investigated. • Signal enhancement was experimentally verified in the Double Pulse technique. • Comparison of the experimental results with the proposed theoretical model • Dependence of the LIBS signal by some experimental parameters.

  11. Qualidade fisiológica de sementes e desempenho de plantas de rúcula no campo Seed physiological quality and field performance of rocket plants

    Directory of Open Access Journals (Sweden)

    Rogério Gomes Pêgo

    2011-08-01

    Full Text Available O estudo teve como objetivo avaliar a influência da qualidade fisiológica de diferentes lotes de sementes de rúcula (Eruca sativa L. no desenvolvimento inicial e na produção comercial. Avaliou-se a qualidade fisiológica das sementes mediante testes de germinação, primeira contagem de germinação, índice de velocidade de germinação, comprimento da raiz primária e da parte aérea, massa fresca e seca de plântulas. Aos 10 dias após a semeadura em campo, avaliou-se a percentagem de emergência, comprimento de raiz e da parte aérea, massa fresca e seca das plântulas. Aos 35 dias após a semeadura, foram avaliados o número de folhas, número de folhas maiores que dez centímetros, massa fresca e seca das plantas. O delineamento experimental foi inteiramente casualizado utilizando-se quatro tratamentos (lotes e quatro repetições. Quanto à qualidade fisiológica das sementes de rúcula, houve estratificação dos lotes, sendo que os mais vigorosos possibilitaram o maior desenvolvimento de raiz e da parte aérea aos 10 dias após a semeadura, entretanto a qualidade fisiológica das sementes não influenciou na produção comercial da cultura.The study had as objective evaluates the influence of different physiologic quality seeds of Eruca sativa L. in the initial development and in the commercial production. It was evaluated the physiological quality of seeds by tests of germination, first count, speed of germination-index, root length and shoot, fresh and dry weight of seedlings. At 10 days after sowing in the field, the percentage of emergence, root length and shoot, fresh and dry plants was estimated. After 35 days of sowing, the number of leaves, number of leaves greater than 10 cm, fresh and dry plants was evaluated. A randomized complete block design was used with four treatments (lots and four replications. There was stratification of lots on the physiological quality of rocket seeds. The seeds vigorous possible the further

  12. Separation of alditols of interest in food products by high-performance anion-exchange chromatography with pulsed amperometric detection.

    Science.gov (United States)

    Corradini, C; Canali, G; Cogliandro, E; Nicoletti, I

    1997-12-12

    High-performance anion-exchange chromatography (HPAEC)-pulsed amperometric detection (PAD) employing a CarboPac MA 1 column was investigated with respect to mobile phase composition, linear response characteristics, repeatability, reproducibility and sensitivity with different alditols used as sugar substitutes in food and confectionery products. The energy-reduced bulk sweeteners isomalt and maltitol were well resolved in less than 25 min by isocratic elution with 600 mM sodium hydroxide solution. HPAEC-PAD was also successfully applied to the determination of alditols in sugar-free products and a low-calorie sweetener containing sorbitol, mannitol and fructose at different levels.

  13. Design Study: Rocket Based MHD Generator

    Science.gov (United States)

    1997-01-01

    This report addresses the technical feasibility and design of a rocket based MHD generator using a sub-scale LOx/RP rocket motor. The design study was constrained by assuming the generator must function within the performance and structural limits of an existing magnet and by assuming realistic limits on (1) the axial electric field, (2) the Hall parameter, (3) current density, and (4) heat flux (given the criteria of heat sink operation). The major results of the work are summarized as follows: (1) A Faraday type of generator with rectangular cross section is designed to operate with a combustor pressure of 300 psi. Based on a magnetic field strength of 1.5 Tesla, the electrical power output from this generator is estimated to be 54.2 KW with potassium seed (weight fraction 3.74%) and 92 KW with cesium seed (weight fraction 9.66%). The former corresponds to a enthalpy extraction ratio of 2.36% while that for the latter is 4.16%; (2) A conceptual design of the Faraday MHD channel is proposed, based on a maximum operating time of 10 to 15 seconds. This concept utilizes a phenolic back wall for inserting the electrodes and inter-electrode insulators. Copper electrode and aluminum oxide insulator are suggested for this channel; and (3) A testing configuration for the sub-scale rocket based MHD system is proposed. An estimate of performance of an ideal rocket based MHD accelerator is performed. With a current density constraint of 5 Amps/cm(exp 2) and a conductivity of 30 Siemens/m, the push power density can be 250, 431, and 750 MW/m(sup 3) when the induced voltage uB have values of 5, 10, and 15 KV/m, respectively.

  14. Ignition transient analysis of solid rocket motor

    Science.gov (United States)

    Han, Samuel S.

    1991-01-01

    Measurement data on the performance of Space Shuttle Solid Rocket Motor show wide variations in the head-end pressure changes and the total thrust build-up during the ignition transient periods. To analyze the flow and thermal behavior in the tested solid rocket motors, a 1-dimensional, ideal gas flow model via the SIMPLE algorithm was developed. Numerical results showed that burning patterns in the star-shaped head-end segment of the propellant and the erosive burning rate are two important factors controlling the ignition transients. The objective of this study is to extend the model to include the effects of aluminum particle commonly used in solid propellants. To treat the effects of aluminum-oxide particles in the combustion gas, conservation of mass, momentum, and energy equations for the particles are added in the numerical formulation and integrated by an inter-phase-slip algorithm.

  15. Performance Prediction and Experimental Investigations on Integral Pulse Tube Cryocooler for 15 W at 70 K Using Indigenously Developed Linear Compressor

    Science.gov (United States)

    Gawali, B. S.; Narayankhedkar, K. G.

    2006-04-01

    Theoretical model based on cyclic analysis has been extended to design the integral pulse tube cryocooler. Cryocooler is developed to match with the indigenously developed opposed piston linear compressor of 30 cc swept volume. The design is carried for the Stirling type Pulse Tube cryocooler to develop 15 W at 70 K. The Pulse Tube cryocooler has been developed with due attention to the heat exchangers and regenerator. Experimental investigations have been carried out for study of the effect of pulse tube aspect ratio and to confirm the consistency of the model and suitability of the linear compressor. Experimental investigation confirmed consistent performance of the linear compressor as well as the Pulse Tube cryocooler.

  16. British used Congreve Rockets to Attack Napoleon

    Science.gov (United States)

    2004-01-01

    Sir William Congreve developed a rocket with a range of about 9,000 feet. The incendiary rocket used black powder, an iron case, and a 16-foot guide stick. In 1806, British used Congreve rockets to attack Napoleon's headquarters in France. In 1807, Congreve directed a rocket attack against Copenhagen.

  17. NASA's Advanced solid rocket motor

    Science.gov (United States)

    Mitchell, Royce E.

    The Advanced Solid Rocket Motor (ASRM) will not only bring increased safety, reliability and performance for the Space Shuttle Booster, it will enhance overall Shuttle safety by effectively eliminating 174 failure points in the Space Shuttle Main Engine throttling system and by reducing the exposure time to aborts due to main engine loss or shutdown. In some missions, the vulnerability time to Return-to-Launch Site aborts is halved. The ASRM uses case joints which will close or remain static under the effects of motor ignition and pressurization. The case itself is constructed of the weldable steel alloy HP 9-4-0.30, having very high strength and with superior fracture toughness and stress corrosion resistance. The internal insulation is strip-wound and is free of asbestos. The nozzle employs light weight ablative parts and is some 5,000 pounds lighter than the Shuttle motor used to date. The payload performance of the ASRM-powered Shuttle is 12,000 pounds higher than that provided by the present motor. This is of particular benefit for payloads delivered to higher inclinations and/or altitudes. The ASRM facility uses state-of-the-art manufacturing techniques, including continuous propellant mixing and direct casting.

  18. NASA's Advanced solid rocket motor

    Science.gov (United States)

    Mitchell, Royce E.

    1993-01-01

    The Advanced Solid Rocket Motor (ASRM) will not only bring increased safety, reliability and performance for the Space Shuttle Booster, it will enhance overall Shuttle safety by effectively eliminating 174 failure points in the Space Shuttle Main Engine throttling system and by reducing the exposure time to aborts due to main engine loss or shutdown. In some missions, the vulnerability time to Return-to-Launch Site aborts is halved. The ASRM uses case joints which will close or remain static under the effects of motor ignition and pressurization. The case itself is constructed of the weldable steel alloy HP 9-4-0.30, having very high strength and with superior fracture toughness and stress corrosion resistance. The internal insulation is strip-wound and is free of asbestos. The nozzle employs light weight ablative parts and is some 5,000 pounds lighter than the Shuttle motor used to date. The payload performance of the ASRM-powered Shuttle is 12,000 pounds higher than that provided by the present motor. This is of particular benefit for payloads delivered to higher inclinations and/or altitudes. The ASRM facility uses state-of-the-art manufacturing techniques, including continuous propellant mixing and direct casting.

  19. Turbopump Design and Analysis Approach for Nuclear Thermal Rockets

    Science.gov (United States)

    Chen, Shu-cheng S.; Veres, Joseph P.; Fittje, James E.

    2006-01-01

    A rocket propulsion system, whether it is a chemical rocket or a nuclear thermal rocket, is fairly complex in detail but rather simple in principle. Among all the interacting parts, three components stand out: they are pumps and turbines (turbopumps), and the thrust chamber. To obtain an understanding of the overall rocket propulsion system characteristics, one starts from analyzing the interactions among these three components. It is therefore of utmost importance to be able to satisfactorily characterize the turbopump, level by level, at all phases of a vehicle design cycle. Here at NASA Glenn Research Center, as the starting phase of a rocket engine design, specifically a Nuclear Thermal Rocket Engine design, we adopted the approach of using a high level system cycle analysis code (NESS) to obtain an initial analysis of the operational characteristics of a turbopump required in the propulsion system. A set of turbopump design codes (PumpDes and TurbDes) were then executed to obtain sizing and performance characteristics of the turbopump that were consistent with the mission requirements. A set of turbopump analyses codes (PUMPA and TURBA) were applied to obtain the full performance map for each of the turbopump components; a two dimensional layout of the turbopump based on these mean line analyses was also generated. Adequacy of the turbopump conceptual design will later be determined by further analyses and evaluation. In this paper, descriptions and discussions of the aforementioned approach are provided and future outlooks are discussed.

  20. Turbopump Design and Analysis Approach for Nuclear Thermal Rockets

    Science.gov (United States)

    Chen, Shu-Cheng S.; Veres, Joseph P.; Fittje, James E.

    2006-01-01

    A rocket propulsion system, whether it is a chemical rocket or a nuclear thermal rocket, is fairly complex in detail but rather simple in principle. Among all the interacting parts, three components stand out: they are pumps & turbines (turbopumps), and the thrust chamber. To obtain an understanding of the overall rocket propulsion system characteristics, one starts from analyzing the interactions among these three components. It is therefore of utmost importance to be able to satisfactorily characterize the turbopump, level by level, at all phases of a vehicle design cycle. Here at the NASA Glenn Research Center, as the starting phase of a rocket engine design, specifically a Nuclear Thermal Rocket Engine design, we adopted the approach of using a high level system cycle analysis code (NESS) to obtain an initial analysis of the operational characteristics of a turbopump required in the propulsion system. A set of turbopump design codes (PumpDes and TurbDes) were then executed to obtain sizing and performance parameters of the turbopump that were consistent with the mission requirements. A set of turbopump analyses codes (PUMPA and TURBA) were applied to obtain the full performance map for each of the turbopump components; a two dimensional layout of the turbopump based on these mean line analyses was also generated. Adequacy of the turbopump conceptual design will later be determined by further analyses and evaluation. In this paper, descriptions and discussions of the aforementioned approach are provided and future outlooks are discussed.

  1. Alternate Propellant Thermal Rocket Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Alternate Propellant Thermal Rocket (APTR) is a novel concept for propulsion of space exploration or orbit transfer vehicles. APTR propulsion is provided by...

  2. Hydrocarbon Rocket Technology Impact Forecasting

    Science.gov (United States)

    Stuber, Eric; Prasadh, Nishant; Edwards, Stephen; Mavris, Dimitri N.

    2012-01-01

    Ever since the Apollo program ended, the development of launch propulsion systems in the US has fallen drastically, with only two new booster engine developments, the SSME and the RS-68, occurring in the past few decades.1 In recent years, however, there has been an increased interest in pursuing more effective launch propulsion technologies in the U.S., exemplified by the NASA Office of the Chief Technologist s inclusion of Launch Propulsion Systems as the first technological area in the Space Technology Roadmaps2. One area of particular interest to both government agencies and commercial entities has been the development of hydrocarbon engines; NASA and the Air Force Research Lab3 have expressed interest in the use of hydrocarbon fuels for their respective SLS Booster and Reusable Booster System concepts, and two major commercially-developed launch vehicles SpaceX s Falcon 9 and Orbital Sciences Antares feature engines that use RP-1 kerosene fuel. Compared to engines powered by liquid hydrogen, hydrocarbon-fueled engines have a greater propellant density (usually resulting in a lighter overall engine), produce greater propulsive force, possess easier fuel handling and loading, and for reusable vehicle concepts can provide a shorter turnaround time between launches. These benefits suggest that a hydrocarbon-fueled launch vehicle would allow for a cheap and frequent means of access to space.1 However, the time and money required for the development of a new engine still presents a major challenge. Long and costly design, development, testing and evaluation (DDT&E) programs underscore the importance of identifying critical technologies and prioritizing investment efforts. Trade studies must be performed on engine concepts examining the affordability, operability, and reliability of each concept, and quantifying the impacts of proposed technologies. These studies can be performed through use of the Technology Impact Forecasting (TIF) method. The Technology Impact

  3. Observations of the initial stage of a rocket-and-wire-triggered lightning discharge

    Science.gov (United States)

    Zhang, Yang; Krehbiel, Paul R.; Zhang, Yijun; Lu, Weitao; Zheng, Dong; Xu, Liangtao; Huang, Zhigang

    2017-05-01

    Observations have been obtained of the initial stage of a rocket-and-wire-triggered lightning flash with a high-resolution broadband VHF interferometer. The discharge produced 54 precursor current pulses (PCPs) over 883 ms during the rocket's ascent. The interferometer observations show that the PCPs were produced by breakdown at the ascending tip of the rocket, and that individual PCPs were produced by weak upward positive breakdown over meters-scale distances, followed by more energetic, fast downward negative breakdown over several tens of meters distance. The average propagation speeds were 5 × 106 m s-1 and 3 × 107 m s-1, respectively. The sustained upward positive leader (UPL) was initiated by a rapid, repetitive burst of 14 precursor pulses. Upon initiation, the VHF radiation abruptly became continuous with time. Significantly, breakdown during the UPL appeared to extend the discharge in a similar manner to that of the precursor pulses.

  4. Not just rocket science

    Energy Technology Data Exchange (ETDEWEB)

    MacAdam, S.; Anderson, R. [Celan Energy Systems, Rancho Cordova, CA (United States)

    2007-10-15

    The paper explains a different take on oxyfuel combustion. Clean Energy Systems (CES) has integrated aerospace technology into conventional power systems, creating a zero-emission power generation technology that has some advantages over other similar approaches. When using coal as a feedstock, the CES process burns syngas rather than raw coal. The process uses recycled water and steam to moderate the temperature, instead of recycled CO{sub 2}. With no air ingress, the CES process produces very pure CO{sub 2}. This makes it possible to capture over 99% of the CO{sub 2} resulting from combustion. CES uses the combustion products to drive the turbines, rather than indirectly raising steam for steam turbines, as in the oxyfuel process used by companies such as Vattenfall. The core of the process is a high-pressure oxy-combustor adapted from rocket engine technology. This combustor burns gaseous or liquid fuels with gaseous oxygen in the presence of water. Fuels include natural gas, coal or coke-derived synthesis gas, landfill and biodigester gases, glycerine solutions and oil/water emulsion. 2 figs.

  5. Analysis of the Fall-1989 two-meter box test bed experiments performed at the Army Pulse Radiation Facility (APRF)

    Science.gov (United States)

    Johnson, J. O.; Drischler, J. D.; Barnes, J. M.

    This report summarizes the results of a benchmark analysis of the Monte Carlo Adjoint Shielding Code System (MASH) against a series of experiments performed at the Army Pulse Radiation Facility (APRF) in Aberdeen Proving Ground, Maryland. The series of experiments was performed in the Fall of 1989 and involved experimentalists from APRF; the Defense Research Establishment Ottawa, Canada (DREO); Bubble Technology Industries, Canada, (BTI); and the Establishment Technique Central de l'Armement, France (ETCA). The 'benchmark' analysis of MASH is designed to determine the capability of MASH to reproduce the measured neutron and gamma ray integral and differential (spectral) data. Results of the 'benchmark' analysis are to be used in the recommendations to the North Atlantic Treaty Organization (NATO) Panel 7 Ad Hoc Group of Shielding Experts for replacing the Vehicle Code System (VCS) with MASH as the reference code of choice for armored vehicle nuclear vulnerability calculations.

  6. Pulse on Pulse

    DEFF Research Database (Denmark)

    Schmidt, Ulrik; Carlson, Merete

    2012-01-01

    and pulsating ‘room’. Hence, the visitors in Pulse Room are invited into a complex scenario that continuously oscillates between various aspects of signification (the light bulbs representing individual lives; the pulse itself as the symbolic ‘rhythm of life’) and instants of pure material processuality......“Pulse on Pulse” investigates the relation between signifying processes and non-signifying material dynamism in the installation Pulse Room (2006-) by Mexican Canadian artist Rafael Lozano-Hemmer. In Pulse Room the sense of pulse is ambiguous. Biorhythms are transmitted from the pulsing energy...... of the visitor’s beating heart to the blink of a fragile light bulb, thereby transforming each light bulb into a register of individual life. But at the same time the blinking light bulbs together produce a chaotically flickering light environment composed by various layers of repetitive rhythms, a vibrant...

  7. EJ-309 pulse shape discrimination performance with a high gamma-ray-to-neutron ratio and low threshold

    Energy Technology Data Exchange (ETDEWEB)

    Kaplan, A.C., E-mail: Alexis.C.Kaplan@gmail.com [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, 2355 Bonisteel Blvd., Ann Arbor, MI 48104 (United States); Nuclear Engineering and Nonproliferation Division, Los Alamos National Laboratory, Los Alamos, NM 87544 (United States); Flaska, M.; Enqvist, A.; Dolan, J.L.; Pozzi, S.A. [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, 2355 Bonisteel Blvd., Ann Arbor, MI 48104 (United States)

    2013-11-21

    Measuring neutrons in the presence of high gamma-ray fluence is a challenge with multi-particle detectors. Organic liquid scintillators such as the EJ-309 are capable of accurate pulse-shape discrimination (PSD) but the chance for particle misclassification is not negligible for some applications. By varying the distance from an EJ-309 scintillator to a strong-gamma-ray source and keeping a weak-neutron source at a fixed position, various gamma-to-neutron ratios can be measured and PSD performance can be quantified. Comparing neutron pulse-height distributions allows for pulse-height specific PSD evaluation, and quantification and visualization of deviation from {sup 252}Cf alone. Even with the addition of the misclassified gamma-rays, the PSD is effective in separating particles so that neutron count rate can be predicted with less than 10% error up to a gamma-to-neutron ratio of almost 650. For applications which can afford a reduction in neutron detection efficiency, PSD can be sufficiently effective in discriminating particles to measure a weak neutron source in a high gamma-ray background. -- Highlights: •We measure neutrons in a high photon background with EJ-309 liquid scintillators. •A low threshold is used to test the limits of particle discrimination. •A weak neutron signal is detectable with a gamma/neutron ratio as high as 770. •Photon pileup most commonly adds to error in classification of neutrons. •Neutron count rates are within 10% of expected rate under high gamma background.

  8. Incorporation of an Energy Equation into a Pulsed Inductive Thruster Performance Model

    Science.gov (United States)

    Polzin, Kurt A.; Reneau, Jarred P.; Sankaran, Kameshwaran

    2011-01-01

    A model for pulsed inductive plasma acceleration containing an energy equation to account for the various sources and sinks in such devices is presented. The model consists of a set of circuit equations coupled to an equation of motion and energy equation for the plasma. The latter two equations are obtained for the plasma current sheet by treating it as a one-element finite volume, integrating the equations over that volume, and then matching known terms or quantities already calculated in the model to the resulting current sheet-averaged terms in the equations. Calculations showing the time-evolution of the various sources and sinks in the system are presented to demonstrate the efficacy of the model, with two separate resistivity models employed to show an example of how the plasma transport properties can affect the calculation. While neither resistivity model is fully accurate, the demonstration shows that it is possible within this modeling framework to time-accurately update various plasma parameters.

  9. Modified pulse electrodeposition of Pt nanocatalyst as high-performance electrode for PEMFC

    Science.gov (United States)

    Fouda-Onana, F.; Guillet, N.; AlMayouf, A. M.

    2014-12-01

    Low platinum loading electrode was successfully deposited by a modified pulse galvanic signal in H2PtCl6 electrolyte using carbon black as support directly on a GDL (Gas Diffusion Layer). SEM images of the deposition were composed by rough Pt particles of 50 nm leading to specific electrochemical surface area of 53 m2 g-1. In spite of large particle size and a low cathode loading of 0.12 mg cm-2, the proton exchange membrane fuel cell (PEMFC) fed with humidified H2 and O2 at 80 °C, 1.5 absolute bar reached 0.2 mA cmPt-2 and 0.1 A mg-1 at 0.9 VIR-free which were twice higher than a reference membrane electrodes assembly (MEA) with a cathode loaded at 0.4 mgPt.cm-2. Such an active cathode electrode may be ascribed to a higher utilization rate of the platinum caused by an efficient catalyst deposition by electrochemical route.

  10. Nuclear Thermal Rocket Element Environmental Simulator (NTREES)

    Science.gov (United States)

    Emrich, William J.

    2008-01-01

    To support a potential future development of a nuclear thermal rocket engine, a state-of-the-art non nuclear experimental test setup has been constructed to evaluate the performance characteristics of candidate fuel element materials and geometries in representative environments. The test device simulates the environmental conditions (minus the radiation) to which nuclear rocket fuel components could be subjected during reactor operation. Test articles mounted in the simulator are inductively heated in such a manner as to accurately reproduce the temperatures and heat fluxes normally expected to occur as a result of nuclear fission while at the same time being exposed to flowing hydrogen. This project is referred to as the Nuclear Thermal Rocket Element Environment Simulator or NTREES. The NTREES device is located at the Marshall Space flight Center in a laboratory which has been modified to accommodate the high powers required to heat the test articles to the required temperatures and to handle the gaseous hydrogen flow required for the tests. Other modifications to the laboratory include the installation of a nitrogen gas supply system and a cooling water supply system. During the design and construction of the facility, every effort was made to comply with all pertinent regulations to provide assurance that the facility could be operated in a safe and efficient manner. The NTREES system can currently supply up to 50 kW of inductive heating to the fuel test articles, although the facility has been sized to eventually allow test article heating levels of up to several megawatts.

  11. Nuclear Thermal Rocket Element Environmental Simulator (NTREES)

    Science.gov (United States)

    Emrich, William J., Jr.

    2008-01-01

    To support the eventual development of a nuclear thermal rocket engine, a state-of-the-art experimental test setup has been constructed to evaluate the performance characteristics of candidate fuel element materials and geometries in representative environments. The test device simulates the environmental conditions (minus the radiation) to which nuclear rocket fuel components will be subjected during reactor operation. Test articles mounted in the simulator are inductively heated in such a manner as to accurately reproduce the temperatures and heat fluxes normally expected to occur as a result of nuclear fission while at the same time being exposed to flowing hydrogen. This project is referred to as the Nuclear Thermal Rocket Element Environment Simulator or NTREES. The NTREES device is located at the Marshall Space flight Center in a laboratory which has been modified to accommodate the high powers required to heat the test articles to the required temperatures and to handle the gaseous hydrogen flow required for the tests. Other modifications to the laboratory include the installation of a nitrogen gas supply system and a cooling water supply system. During the design and construction of the facility, every effort was made to comply with all pertinent regulations to provide assurance that the facility could be operated in a safe and efficient manner. The NTREES system can currently supply up to 50 kW of inductive heating to the fuel test articles, although the facility has been sized to eventually allow test article heating levels of up to several megawatts.

  12. NASA Space Rocket Logistics Challenges

    Science.gov (United States)

    Neeley, James R.; Jones, James V.; Watson, Michael D.; Bramon, Christopher J.; Inman, Sharon K.; Tuttle, Loraine

    2014-01-01

    The Space Launch System (SLS) is the new NASA heavy lift launch vehicle and is scheduled for its first mission in 2017. The goal of the first mission, which will be uncrewed, is to demonstrate the integrated system performance of the SLS rocket and spacecraft before a crewed flight in 2021. SLS has many of the same logistics challenges as any other large scale program. Common logistics concerns for SLS include integration of discreet programs geographically separated, multiple prime contractors with distinct and different goals, schedule pressures and funding constraints. However, SLS also faces unique challenges. The new program is a confluence of new hardware and heritage, with heritage hardware constituting seventy-five percent of the program. This unique approach to design makes logistics concerns such as commonality especially problematic. Additionally, a very low manifest rate of one flight every four years makes logistics comparatively expensive. That, along with the SLS architecture being developed using a block upgrade evolutionary approach, exacerbates long-range planning for supportability considerations. These common and unique logistics challenges must be clearly identified and tackled to allow SLS to have a successful program. This paper will address the common and unique challenges facing the SLS programs, along with the analysis and decisions the NASA Logistics engineers are making to mitigate the threats posed by each.

  13. Environmentally compatible solid rocket propellants

    Science.gov (United States)

    Jacox, James L.; Bradford, Daniel J.

    1995-01-01

    Hercules' clean propellant development research is exploring three major types of clean propellant: (1) chloride-free formulations (no chlorine containing ingredients), being developed on the Clean Propellant Development and Demonstration (CPDD) contract sponsored by Phillips Laboratory, Edwards Air Force Base, CA; (2) low HCl scavenged formulations (HCl-scavenger added to propellant oxidized with ammonium perchlorate (AP)); and (3) low HCl formulations oxidized with a combination of AN and AP (with or without an HCl scavenger) to provide a significant reduction (relative to current solid rocket boosters) in exhaust HCl. These propellants provide performance approaching that of current systems, with less than 2 percent HCl in the exhaust, a significant reduction (greater than or equal to 70 percent) in exhaust HCl levels. Excellent processing, safety, and mechanical properties were achieved using only readily available, low cost ingredients. Two formulations, a sodium nitrate (NaNO3) scavenged HTPB and a chloride-free hydroxy terminated polyether (HTPE) propellant, were characterized for ballistic, mechanical, and rheological properties. In addition, the hazards properties were demonstrated to provide two families of class 1.3, 'zero-card' propellants. Further characterization is planned which includes demonstration of ballistic tailorability in subscale (one to 70 pound) motors over the range of burn rates required for retrofit into current Hercules space booster designs (Titan 4 SRMU and Delta 2 GEM).

  14. Low temperature synthesis of hierarchical TiO2 nanostructures for high performance perovskite solar cells by pulsed laser deposition.

    Science.gov (United States)

    Yang, Bin; Mahjouri-Samani, Masoud; Rouleau, Christopher M; Geohegan, David B; Xiao, Kai

    2016-10-21

    A promising way to advance perovskite solar cells is to improve the quality of the electron transport material -e.g., titanium dioxide (TiO2) - in a direction that increases electron transport and extraction. Although dense TiO2 films are easily grown in solution, efficient electron extraction suffers due to a lack of interfacial contact area with the perovskites. Conversely, mesoporous films do offer high surface-area-to-volume ratios, thereby promoting efficient electron extraction, but their morphology is relatively difficult to control via conventional solution synthesis methods. Here, a pulsed laser deposition method was used to assemble TiO2 nanoparticles into TiO2 hierarchical architectures exhibiting an anatase crystal structure, and prototype solar cells employing these structures yielded power conversion efficiencies of ∼14%. Our approach demonstrates a way to grow high aspect-ratio TiO2 nanostructures for improved interfacial contact between TiO2 and perovskite materials, leading to high electron-hole pair separation and electron extraction efficiencies for superior photovoltaic performance. Compared to previous pulsed laser deposition-synthesized TiO2 mesoporous crystalline networks that needed post-thermal annealing at 500 °C to form mesoporous crystalline networks, our relatively low temperature (300 °C) TiO2 processing method may promote reduced energy-consumption during device fabrication, as well as enable compatibility with flexible polymer substrates such as polyimide.

  15. Lyman alpha coronagraph research sounding rocket program

    Science.gov (United States)

    Parkinson, W. H.; Kohl, J. L.

    1985-01-01

    The ultraviolet light coronagraph was developed and successfully flown on three rocket flights on 13 April 1979, 16 February 1980 and 20 July 1982. During each of these flights, the Ultraviolet Light Coronagraph was flown jointly with the White Light Coronagraph provided by the High Altitude Observatory. Ultraviolet diagnostic techniques and instrumentation for determining the basic plasma parameters of solar wind acceleration regions in the extended corona were developed and verified and the understanding of the physics of the corona through the performance, analysis and interpretation of solar observations advanced. Valuable UV diagnostics can be performed in the absence of a natural solar eclipse.

  16. Comparison of concentration pulse and tracer pulse chromatography: experimental determination of eluent uptake by bridged-ethylene hybrid ultra high performance liquid chromatography packings

    Science.gov (United States)

    Excess volume isotherms of acetonitrile and methanol sorbed on a C18 BEH UHPLC packing were determined over a range of pressure, temperature, flow rate and eluent composition. The isotherm measurements were carried out by two independent experimental methods, viz., concentration pulse and tracer pul...

  17. Nuclear thermal rocket nozzle testing and evaluation program

    Science.gov (United States)

    Davidian, Kenneth O.; Kacynski, Kenneth J.

    1993-01-01

    Performance characteristics of the Nuclear Thermal Rocket can be enhanced through the use of unconventional nozzles as part of the propulsion system. The Nuclear Thermal Rocket nozzle testing and evaluation program being conducted at the NASA Lewis is outlined and the advantages of a plug nozzle are described. A facility description, experimental designs and schematics are given. Results of pretest performance analyses show that high nozzle performance can be attained despite substantial nozzle length reduction through the use of plug nozzles as compared to a convergent-divergent nozzle. Pretest measurement uncertainty analyses indicate that specific impulse values are expected to be within + or - 1.17 pct.

  18. Inter-Batch Variation and the Effect of Casting Vacuum on Ballistic and Mechanical Properties of a High Performing Cast Composite Rocket Propellant

    Science.gov (United States)

    2014-12-01

    13 8 Scrape down - - - 9 Mix 30 0 45 10 Scrape down - - - 11 Add IPDI 30 1 4 12 Scrape down - - - 13 Mix 30 0 20 The dry clumps of material...http:// web -vic.dsto.defence.gov.au/workareas/library/resources/dsto_thesaurus.shtml Booster, HTPB, high performance composite propellant 19

  19. Three-dimensional microstructure of high-performance pulsed-laser deposited Ni-YSZ SOFC anodes.

    Science.gov (United States)

    Kennouche, David; Hong, Jongsup; Noh, Ho-Sung; Son, Ji-Won; Barnett, Scott A

    2014-08-07

    The Ni-yttria-stabilized zirconia (YSZ) anode functional layer in solid oxide fuel cells produced by pulsed laser-deposition was studied using three-dimensional tomography. Anode feature sizes of ~130 nm were quite small relative to typical anodes, but errors arising in imaging and segmentation were shown using a sensitivity analysis to be acceptable. Electrochemical characterization showed that these cells achieved a relatively high maximum power density of 1.4 W cm(-2) with low cell resistance at an operating temperature of 600 °C. The tomographic data showed anode three-phase boundary density of ~56 μm(-2), more than 10 times the value observed in conventional Ni-YSZ anodes. Anode polarization resistance values, predicted by combining the structural data and literature values of three-phase boundary resistance in an electrochemical model, were consistent with measured electrochemical impedance spectra, explaining the excellent intermediate-temperature performance of these cells.

  20. Rocket Science 101 Interactive Educational Program

    Science.gov (United States)

    Armstrong, Dennis; Funkhouse, Deborah; DiMarzio, Donald

    2007-01-01

    To better educate the public on the basic design of NASA s current mission rockets, Rocket Science 101 software has been developed as an interactive program designed to retain a user s attention and to teach about basic rocket parts. This program also has helped to expand NASA's presence on the Web regarding educating the public about the Agency s goals and accomplishments. The software was designed using Macromedia s Flash 8. It allows the user to select which type of rocket they want to learn about, interact with the basic parts, assemble the parts to create the whole rocket, and then review the basic flight profile of the rocket they have built.

  1. Cycle Performance of a Pulse Detonation Engine with Supercritical Fuel Injection

    Science.gov (United States)

    2006-03-23

    AFROTC at Purdue University. His first assignment was in the Mature and Proven Aircraft Directorate ( MAPA ) of the Ogden Air Logistics Center at...Hill AFB, UT. While assigned to MAPA , Lieutenant Helfrich performed duties as an A-10 Systems Engineer. In September of 2004, he entered the Air

  2. Rocket Science at the Nanoscale.

    Science.gov (United States)

    Li, Jinxing; Rozen, Isaac; Wang, Joseph

    2016-06-28

    Autonomous propulsion at the nanoscale represents one of the most challenging and demanding goals in nanotechnology. Over the past decade, numerous important advances in nanotechnology and material science have contributed to the creation of powerful self-propelled micro/nanomotors. In particular, micro- and nanoscale rockets (MNRs) offer impressive capabilities, including remarkable speeds, large cargo-towing forces, precise motion controls, and dynamic self-assembly, which have paved the way for designing multifunctional and intelligent nanoscale machines. These multipurpose nanoscale shuttles can propel and function in complex real-life media, actively transporting and releasing therapeutic payloads and remediation agents for diverse biomedical and environmental applications. This review discusses the challenges of designing efficient MNRs and presents an overview of their propulsion behavior, fabrication methods, potential rocket fuels, navigation strategies, practical applications, and the future prospects of rocket science and technology at the nanoscale.

  3. Low-thrust rocket trajectories

    Energy Technology Data Exchange (ETDEWEB)

    Keaton, P.W.

    1986-01-01

    The development of low-thrust propulsion systems to complement chemical propulsion systems will greatly enhance the evolution of future space programs. Two advantages of low-thrust rockets are stressed: first, in a strong gravitational field, such as occurs near the Earth, freighter missions with low-thrust engines require one-tenth as much propellant as do chemical engines. Second, in a weak gravitational field, such as occurs in the region between Venus and Mars, low-thrust rockets are faster than chemical rockets with comparable propellant mass. The purpose here is to address the physics of low-thrust trajectories and to interpret the results with two simple models. Analytic analyses are used where possible - otherwise, the results of numerical calculations are presented in graphs. The author has attempted to make this a self-contained report. 57 refs., 10 figs.

  4. Low-thrust rocket trajectories

    Energy Technology Data Exchange (ETDEWEB)

    Keaton, P.W.

    1987-03-01

    The development of low-thrust propulsion systems to complement chemical propulsion systems will greatly enhance the evolution of future space programs. Two advantages of low-thrust rockets are stressed: first, in a strong gravitational field, such as occurs near the Earth, freighter missions with low-thrust engines require one-tenth as much propellant as do chemical engines. Second, in a weak gravitational field, such as occurs in the region between Venus and Mars, low-thrust rockets are faster than chemical rockets with comparable propellant mass. The purpose here is to address the physics of low-thrust trajectories and to interpret the results with two simple models. Analytic analyses are used where possible - otherwise, the results of numerical calculations are presented in graphs. The author has attempted to make this a self-contained report.

  5. LONG-PULSE, HIGH-PERFORMANCE DISCHARGES IN THE DIII-D TOKAMAK

    Energy Technology Data Exchange (ETDEWEB)

    T.C. LUCE; M.R. WADE; P.A. POLITZER; S.L. ALLEN; M E. AUSTIN; D.R. BAKER; B.D. BRAY; D.P. BRENNAN; K.H. BURRELL; T.A. CASPER; M.S. CHU; J.D. De BOO; E.J. DOYLE; J.R. FERRON; A.M. GAROFALO; P.GOHIL; I.A. GORELOV; C.M. GREENFIELD; R.J. GROEBNER; W.W. HEIBRINK; C.-L. HSIEH; A.W. HYATT; R.JAYAKUMAR; J.E.KINSEY; R.J. LA HAYE; L.L.LAO; C.J.LASNIER; E.A. LAZARUS; A.W. LEONARD; Y.R.LIN-LIU; J.LOHR; M.A. MAKOWSKI; M.MURAKAMI; C.C.PETTY; R.I. PINSKER; R.PRATER; C.L. RETTIG; T.L. RHODES; B.W. RICE; E.J. STRAIT; T.S. TAYLOR; D.M. THOMAS; A.D. TURNBULL; J.G. WATKINS; W.P.WEST; K.-L. WONG

    2000-10-01

    Significant progress in obtaining high performance discharges for many energy confinement times in the DIII-D tokamak has been realized since the previous IAEA meeting. In relation to previous discharges, normalized performance {approx}10 has been sustained for >5 {tau}{sub E} with q{sub min} >1.5. (The normalized performance is measured by the product {beta}{sub N} H{sub 89} indicating the proximity to the conventional {beta} limits and energy confinement quality, respectively.) These H-mode discharges have an ELMing edge and {beta} {approx}{le} 5%. The limit to increasing {beta} is a resistive wall mode, rather than the tearing modes previously observed. Confinement remains good despite the increase in q. The global parameters were chosen to optimize the potential for fully non-inductive current sustainment at high performance, which is a key program goal for the DIII-D facility in the next two years. Measurement of the current density and loop voltage profiles indicate {approx}75% of the current in the present discharges is sustained non-inductively. The remaining ohmic current is localized near the half radius. The electron cyclotron heating system is being upgraded to replace this remaining current with ECCD. Density and {beta} control, which are essential for operating advanced tokamak discharges, were demonstrated in ELMing H-mode discharges with {beta}{sub N}H{sub 89} {approx} 7 for up to 6.3 s or {approx} 34 {tau}{sub E}. These discharges appear to be in resistive equilibrium with q{sub min} {approx} 1.05, in agreement with the current profile relaxation time of 1.8 s.

  6. Characterization of nal powders for rocket propulsion

    Science.gov (United States)

    Merotto, L.; Galfetti, L.; Colombo, G.; DeLuca, L. T.

    2011-10-01

    Nanosized metal powders are known to significantly improve both solid and hybrid rocket performance, but have some drawbacks in terms of cost, safety, and possible influence on propellant mechanical properties. Performance enhancement through nanosized metal or metal hydride addition to solid fuels is currently under investigation also for hybrid propulsion. Therefore, a preburning characterization of the powders used in solid propellant or fuel manufacturing is useful to assess their effects on the ballistic properties and engine performance. An investigation concerning the comparative characterization of several aluminum powders having different particle size, age, and coating is presented. Surface area, morphology, chemical species concentration and characteristics, surface passivation layers, surface and subsurface chemical composition, ignition temperature and ignition delay are investigated. The aim of this characterization is to experimentally assess the effect of the nAl powder properties on ballistic characteristics of solid fuels and solidrocket composite-propellant performance, showing an increase in terms of Is caused by the decrease of two-phase losses in solid and a possible significant rf increase in hybrid rockets.

  7. A Tapered Chalcogenide Microstructured Optical Fiber for Mid-IR Parabolic Pulse Generation: Design and Performance Study

    CERN Document Server

    Barh, Ajanta; Varshney, Ravi K; Pal, Bishnu P

    2013-01-01

    This paper presents a theoretical design of chalcogenide glass based tapered microstructured optical fiber (MOF) to generate high power parabolic pulses (PPs) at the mid-IR wavelength (~ 2 {\\mu}m). We optimize fiber cross-section by the multipole method and studied pulse evolution by well known Symmetrized Split-Step Fourier Method. Our numerical investigation reveals the possibility of highly efficient PP generation within a very short length (~ 18 cm) of this MOF for a Gaussian input pulse of 60 W peak power and FWHM of 3.5 ps. We examined quality of the generated PP by calculating the misfit parameter including the third order dispersion and fiber loss. Further, the effects of variations in input pulse power, pulse width and pulse energy on generated PP were also studied.

  8. Microstructure and performance of solid TC4 titanium alloy subjected to the high pulsed magnetic field treatment

    Energy Technology Data Exchange (ETDEWEB)

    Li, G.R., E-mail: liguirong@ujs.edu.cn; Li, Y.M.; Wang, F.F.; Wang, H.M.

    2015-09-25

    Highlights: • A high pulsed magnetic field was introduced to process the solid titanium alloy. • The phase transition from beta to alpha in processed alloy was discovered. • The magneto-plasticity effect was found and highlighted. • The strength and toughness of treated alloy were enhanced synchronously. - Abstract: The effect of high pulsed magnetic field with different magnetic induced intensity (B) on the microstructure and mechanical performance of solid TC4 titanium alloy was investigated. The microstructure morphology was characterized by metallographic microscope, scanning electronic microscopy and transmission electronic microscopy. The results show that the magnetic has induced the phase transformation from β to α. At 4 T the volume fraction of α phase has increased from 49% (B = 0) to 59%. Meanwhile, compared to that of original sample the dislocation density at 3 T is 4.8 times, which was the result of magneto-plasticity effect. However, the dislocation density will not always increase with B due to the dislocation pile-up effect. The mechanical properties tests show that the strength of materials is enhanced with the B increase within a certain scope. The strength and elongation of processed TC4 alloy exhibit the obvious changes: when B = 3 T the maximum strength reaches 1330 MPa which ascribes to the dislocation strengthening. It is enhanced by 7.6% compared to that of original sample. It is noted that when B = 4 T the strength and toughness are improved simultaneously which are attributed to not only the dislocation strengthening but also the amount, distribution and morphology of α phase.

  9. Some typical solid propellant rocket motors

    NARCIS (Netherlands)

    Zandbergen, B.T.C.

    2013-01-01

    Typical Solid Propellant Rocket Motors (shortly referred to as Solid Rocket Motors; SRM's) are described with the purpose to form a database, which allows for comparative analysis and applications in practical SRM engineering.

  10. Integrated Composite Rocket Nozzle Extension Project

    Data.gov (United States)

    National Aeronautics and Space Administration — ORBITEC proposes to develop and demonstrate an Integrated Composite Rocket Nozzle Extension (ICRNE) for use in rocket thrust chambers. The ICRNE will utilize an...

  11. Some typical solid propellant rocket motors

    NARCIS (Netherlands)

    Zandbergen, B.T.C.

    2013-01-01

    Typical Solid Propellant Rocket Motors (shortly referred to as Solid Rocket Motors; SRM's) are described with the purpose to form a database, which allows for comparative analysis and applications in practical SRM engineering.

  12. Identification of rocket-induced acoustic waves in the ionosphere

    Science.gov (United States)

    Mabie, Justin; Bullett, Terence; Moore, Prentiss; Vieira, Gerald

    2016-10-01

    Acoustic waves can create plasma disturbances in the ionosphere, but the number of observations is limited. Large-amplitude acoustic waves generated by energetic sources like large earthquakes and tsunamis are more readily observed than acoustic waves generated by weaker sources. New observations of plasma displacements caused by rocket-generated acoustic waves were made using the Vertically Incident Pulsed Ionospheric Radar (VIPIR), an advanced high-frequency radar. Rocket-induced acoustic waves which are characterized by low amplitudes relative to those induced by more energetic sources can be detected in the ionosphere using the phase data from fixed frequency radar observations of a plasma layer. This work is important for increasing the number and quality of observations of acoustic waves in the ionosphere and could help improve the understanding of energy transport from the lower atmosphere to the thermosphere.

  13. Nuclear Thermal Rocket Simulation in NPSS

    Science.gov (United States)

    Belair, Michael L.; Sarmiento, Charles J.; Lavelle, Thomas M.

    2013-01-01

    Four nuclear thermal rocket (NTR) models have been created in the Numerical Propulsion System Simulation (NPSS) framework. The models are divided into two categories. One set is based upon the ZrC-graphite composite fuel element and tie tube-style reactor developed during the Nuclear Engine for Rocket Vehicle Application (NERVA) project in the late 1960s and early 1970s. The other reactor set is based upon a W-UO2 ceramic-metallic (CERMET) fuel element. Within each category, a small and a large thrust engine are modeled. The small engine models utilize RL-10 turbomachinery performance maps and have a thrust of approximately 33.4 kN (7,500 lbf ). The large engine models utilize scaled RL-60 turbomachinery performance maps and have a thrust of approximately 111.2 kN (25,000 lbf ). Power deposition profiles for each reactor were obtained from a detailed Monte Carlo N-Particle (MCNP5) model of the reactor cores. Performance factors such as thermodynamic state points, thrust, specific impulse, reactor power level, and maximum fuel temperature are analyzed for each engine design.

  14. Summarization on variable liquid thrust rocket engines

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The technology actuality and development trend of variable thrust rocket engines at home and abroad are summarized. Key technologies of developing variable thrust rocket engines are analyzed. Development advices on developing variable thrust rocket engines that are adapted to the situation of our country are brought forward.

  15. Nuclear-Thermal Rocket Orbits Mars

    Science.gov (United States)

    1960-01-01

    Originally investigated in the 1960's by Marshall Space Flight Center plarners as part of the Nuclear Energy for Rocket Vehicle Applications (NERVA) program, nuclear-thermal rocket propulsion has been more recently considered in spacecraft designs for interplanetary human exploration. This artist's concept illustrates a nuclear-thermal rocket with an aerobrake disk as it orbits Mars.

  16. Measuring Model Rocket Engine Thrust Curves

    Science.gov (United States)

    Penn, Kim; Slaton, William V.

    2010-01-01

    This paper describes a method and setup to quickly and easily measure a model rocket engine's thrust curve using a computer data logger and force probe. Horst describes using Vernier's LabPro and force probe to measure the rocket engine's thrust curve; however, the method of attaching the rocket to the force probe is not discussed. We show how a…

  17. Measuring Model Rocket Engine Thrust Curves

    Science.gov (United States)

    Penn, Kim; Slaton, William V.

    2010-01-01

    This paper describes a method and setup to quickly and easily measure a model rocket engine's thrust curve using a computer data logger and force probe. Horst describes using Vernier's LabPro and force probe to measure the rocket engine's thrust curve; however, the method of attaching the rocket to the force probe is not discussed. We show how a…

  18. Performance of a 4H-SiC Schottky diode as a compact sized detector for neutron pulse form measurements

    Science.gov (United States)

    Wu, Jian; Li, Meng; Jiang, Yong; Li, Junjie; Zhang, Yi; Gao, Hui; Liu, Xiaobo; Du, Jinfeng; Zou, Dehui; Fan, Xiaoqiang; Gan, Lei; Peng, Cheng; Lu, Yi; Lei, Jiarong

    2015-01-01

    4H-silicon carbide (4H-SiC) detectors are desirable for neutron pulse form measurement for their compact size, excellent radiation resistance and hydrogen free composition. The aim of this study is to investigate the use of a 4H-SiC detector to measure the pulse form of a neutron burst. A 4H-SiC detector is fabricated and tested in the pulsed neutron field of the Chinese Fast Burst Reactor II (CFBR II). Important parameters such as the breeding period and the FWHM of the neutron pulse are derived from the experimental result of the 4H-SiC detector. These parameters agree well with those from a plastic scintillator detector. The divergences are only 0.5%, demonstrating that the 4H-SiC detector can yield a high fidelity time profile of the CFBR II pulse. The difference in peak centroid of alpha spectra is negligible for the 4H-SiC detector even after 18 reactor pulses (a neutron fluence of 8.41×1012 cm-2), confirming the excellent radiation hardness of the 4H-SiC detector in pulsed neutron field. This study therefore indicates that 4H-SiC detectors can be usable as a compact sized detector to measure neutron pulses.

  19. Iridium-Coated Rhenium Radiation-Cooled Rockets

    Science.gov (United States)

    Reed, Brian D.; Biaglow, James A.; Schneider, Steven J.

    1997-01-01

    Radiation-cooled rockets are used for a range of low-thrust propulsion functions, including apogee insertion, attitude control, and repositioning of satellites, reaction control of launch vehicles, and primary propulsion for planetary space- craft. The key to high performance and long lifetimes for radiation-cooled rockets is the chamber temperature capability. The material system that is currently used for radiation-cooled rockets, a niobium alloy (C103) with a fused silica coating, has a maximum operating temperature of 1370 C. Temperature limitations of C103 rockets force the use of fuel film cooling, which degrades rocket performance and, in some cases, imposes a plume contamination issue from unburned fuel. A material system composed of a rhenium (Re) substrate and an iridium (Ir) coating has demonstrated operation at high temperatures (2200 C) and for long lifetimes (hours). The added thermal margin afforded by iridium-coated rhenium (Ir/Re) allows reduction or elimination of fuel film cooling. This, in turn, leads to higher performance and cleaner spacecraft environments. There are ongoing government- and industry-sponsored efforts to develop flight Ir/ Re engines, with the primary focus on 440-N, apogee insertion engines. Complementing these Ir/Re engine development efforts is a program to address specific concerns and fundamental characterization of the Ir/Re material system, including (1) development of Ir/Re rocket fabrication methods, (2) establishment of critical Re mechanical properly data, (3) development of reliable joining methods, and (4) characterization of Ir/Re life-limiting mechanisms.

  20. Characterization of pulsed x-ray beams for tests of electronic dosemeter performance; Caracterizacao de feixes de raios X pulsados para testes de desempenho de dosimetros eletronicos

    Energy Technology Data Exchange (ETDEWEB)

    Guimaraes, Margarete C.; Silva, Teogenes A. da, E-mail: mcg@cdtn.br, E-mail: silvata@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil). Curso de Pos-Graduacao em Ciencias e Tecnologia das Radiacoes, Materiais e Minerais

    2013-10-01

    Electronic dosimeters, due to direct reading, have been increasingly used for individual or area monitoring for purposes of radiation protection in X-ray fields used in diagnostic radiology. Deficiencies of performance in pulsed beams of such dosimeters have been published, which are not detected by the calibration procedures and performance tests established by international standards only for continuous beams of radiation. In Brazil, there are no performance requirements of dosimeters in pulsed beams, or a laboratory that performs testing for reliability in the use of dosimeters. This study aims to characterize the X-ray machine Medical VMI 800 Plus in the Laboratory Calibration of Dosimeters of CDTN/CNEN - Brazilian CNEN institute - and study the feasibility of its use for performance testing of electronic dosimeters. (author)

  1. Physico-Chemical Research on the Sounding Rocket Maser 13

    Science.gov (United States)

    Lockowandt, Christian; Kemi, Stig; Abrahamsson, Mattias; Florin, Gunnar

    MASER is a sounding rocket platform for short-duration microgravity experiments, providing the scientific community with an excellent microgravity tool. The MASER programme has been running by SSC from 1987 and has up to 2012 provided twelve successful flights for microgravity missions with 6-7 minutes of microgravity, the g-level is normally below 1x10-5 g. The MASER 13 is planned to be launched in spring 2015 from Esrange Space Center in Northern Sweden. The rocket will carry four ESA financed experiment modules. The MASER 13 vehicle will be propelled by the 2-stage solid fuel VSB-30 rocket motor, which provided the 390 kg payload with an apogee of 260 km and 6 and a half minutes of microgravity. Swedish Space Corporation carries out the MASER missions for ESA and the program is also available for other customers. The payload comprise four different experiment modules of which three could be defined as physic-chemical research; XRMON-SOL, CDIC-3, MEDI. It also comprises the Maser Service Module and the recovery system. The Service Module provided real-time 5 Mbps down-link of compressed experiment digital video data from the on-board cameras, as well as high-speed housekeeping telemetry data. XRMON-SOL In this experiment the influence of gravity on the formation of an equiaxed microstructure will be investigated. Special attention will be put on the aspect of nucleation, segregation and impingement. The experiment scope is to melt and solidify an AlCu-alloy sample in microgravity. The solidification will be performed in an isothermal environment. The solidification process will be monitored and recorded with X-ray image during the whole flight, images will also be down-linked to ground for real-time monitoring and possible interaction. CDIC-3 The goal is to study in migrogravity the spatio-temporal dynamics of a chemical front travelling in a thin solution layer open to the air and specifically the respective role of Marangoni and density-related hydrodynamic

  2. Parallelization of Rocket Engine System Software (Press)

    Science.gov (United States)

    Cezzar, Ruknet

    1996-01-01

    The main goal is to assess parallelization requirements for the Rocket Engine Numeric Simulator (RENS) project which, aside from gathering information on liquid-propelled rocket engines and setting forth requirements, involve a large FORTRAN based package at NASA Lewis Research Center and TDK software developed by SUBR/UWF. The ultimate aim is to develop, test, integrate, and suitably deploy a family of software packages on various aspects and facets of rocket engines using liquid-propellants. At present, all project efforts by the funding agency, NASA Lewis Research Center, and the HBCU participants are disseminated over the internet using world wide web home pages. Considering obviously expensive methods of actual field trails, the benefits of software simulators are potentially enormous. When realized, these benefits will be analogous to those provided by numerous CAD/CAM packages and flight-training simulators. According to the overall task assignments, Hampton University's role is to collect all available software, place them in a common format, assess and evaluate, define interfaces, and provide integration. Most importantly, the HU's mission is to see to it that the real-time performance is assured. This involves source code translations, porting, and distribution. The porting will be done in two phases: First, place all software on Cray XMP platform using FORTRAN. After testing and evaluation on the Cray X-MP, the code will be translated to C + + and ported to the parallel nCUBE platform. At present, we are evaluating another option of distributed processing over local area networks using Sun NFS, Ethernet, TCP/IP. Considering the heterogeneous nature of the present software (e.g., first started as an expert system using LISP machines) which now involve FORTRAN code, the effort is expected to be quite challenging.

  3. Ontogenic profiling of glucosinolates, flavonoids, and other secondary metabolites in Eruca sativa (salad rocket), Diplotaxis erucoides (wall rocket), Diplotaxis tenuifolia (wild rocket), and Bunias orientalis (Turkish rocket).

    Science.gov (United States)

    Bennett, Richard N; Rosa, Eduardo A S; Mellon, Fred A; Kroon, Paul A

    2006-05-31

    As an influence of the Mediterranean diet, rocket species such as Eruca sativa L., Diplotaxis species, and Bunias orientalis L. are eaten all over the world at different ontogenic stages in salads and soups. They are all species within the plant order Capparales (glucosinolate-containing species), and all are from the family Brassicaceae. Predominantly, the leaves of these species are eaten raw or cooked, although Eruca flowers are also consumed. There is considerable potential with raw plant material for a higher exposure to bioactive phytochemicals such as glucosinolates, their hydrolysis products, and also phenolics, flavonoids, and vitamins such as vitamin C. These compounds are susceptible to ontogenic variation, and the few published studies that have addressed this topic have been inconsistent. Thus, an ontogenic study was performed and all samples were analyzed using a previously developed robust liquid chromatography/mass spectrometry method for the identification and quantification of the major phytochemicals in all tissues of the rocket species. Seeds and roots of both Eruca and Diplotaxis contained predominantly 4-methylthiobutylglucosinolate. Leaves of Eruca and Diplotaxis contained high amounts of 4-mercaptobutylglucosinolate with lower levels of 4-methylthiobutlyglucosinolate and 4-methylsulfinylbutylglucosinolate. Flowers of Eruca and Diplotaxiscontained predominantly 4-methylsulfinylbutyl-glucosinolate. In addition, roots of both Diplotaxisspecies contained 4-hydroxybenzylglucosinolate but 4-hydroxybenzylglucosinolate was absent from roots of Eruca. Seeds and seedlings of all Eruca contained N-heterocyclic compounds but no sinapine, whereas Diplotaxis contained sinapine but not the N-heterocycles. In all tissues of B. orientalis, 4-hydroxybenzylglucosinolate and 4-methylsulfinyl-3-butenylglucosinolate were predominant. All rocket tissues, except roots, contained significant levels of polyglycosylated flavonoids, with/without hydroxycinnamoyl

  4. Experimental study of the influence of cold heat exchanger geometry on the performance of a co-axial pulse tube cooler

    NARCIS (Netherlands)

    Pang, Xiaomin; Dai, Wei; Wang, Xiaotao; Vanapalli, S.; Luo, Ercang

    2016-01-01

    Improving the performance of the pulse tube cooler is one of the important objectives of the current studies. Besides the phase shifters and regenerators, heat exchangers also play an important role in determining the system efficiency and cooling capacity. A series of experiments on a 10 W @ 77 K c

  5. The Application of Counter-Rotating Turbine in Rocket Turbopump

    Directory of Open Access Journals (Sweden)

    Tang Fei

    2008-01-01

    Full Text Available Counter rotating turbine offers advantages on weight, volume, efficiency, and maneuverability relative to the conventional turbine because of its special architecture. Nowadays, it has been a worldwide research emphasis and has been used widely in the aeronautic field, while its application in the astronautic field is seldom investigated. Researches of counter rotating turbine for rocket turbopump are reviewed in this paper. A primary analysis of a vaneless counter rotating-turbine configuration with rotors of different diameters and rotational speeds is presented. This unconventional configuration meets the requirements of turbopump and may benefit the performance and reliability of rocket engines.

  6. Rocket and laboratory studies in aeronomy and astrophysics

    Science.gov (United States)

    Feldman, P. D.

    1986-01-01

    Progress from March 1, 1986 to August 31, 1986 is covered and includes the work performed in response to a proposal entitled A Spartan Payload for Spatially Resolved Spectroscopy of Extended Faint Sources in the Extreme Ultraviolet (EUV). During this period, one rocket was launched, the reflight of the payload to observe Halley's comet on March 13, 1986. Most of the effort during this period was concentrated on detailed mechanical and electronic design of a Spartan payload and on the reduction and analysis of the data from the two Halley rocket flights and from the UVX experiment which flew on STS-61C in January 1986.

  7. Rocket and laboratory studies in aeronomy and astronomy

    Science.gov (United States)

    Feldman, P. D.

    1983-01-01

    Data extracted from semi-annual status reports presented include: a list of all sounding rocket launches performed under NASA sponsorship; a list of Ph.D. and M.A. degrees awarded to students who worked in these programs; a summary bibliography of all publications through 1983; the most recent list of the publications from the IUE program; a summary of instrument development supported by the Johns Hopkins sounding rocket program; and a list of faculty and post-doctoral research associates whose work was supported by this grant.

  8. Chemical rocket propulsion a comprehensive survey of energetic materials

    CERN Document Server

    Shimada, Toru; Sinditskii, Valery; Calabro, Max

    2017-01-01

    Developed and expanded from the work presented at the New Energetic Materials and Propulsion Techniques for Space Exploration workshop in June 2014, this book contains new scientific results, up-to-date reviews, and inspiring perspectives in a number of areas related to the energetic aspects of chemical rocket propulsion. This collection covers the entire life of energetic materials from their conceptual formulation to practical manufacturing; it includes coverage of theoretical and experimental ballistics, performance properties, as well as laboratory-scale and full system-scale, handling, hazards, environment, ageing, and disposal. Chemical Rocket Propulsion is a unique work, where a selection of accomplished experts from the pioneering era of space propulsion and current technologists from the most advanced international laboratories discuss the future of chemical rocket propulsion for access to, and exploration of, space. It will be of interest to both postgraduate and final-year undergraduate students in...

  9. Vibration Isolation Design for the Micro-X Rocket Payload

    Science.gov (United States)

    Danowski, M. E.; Heine, S. N. T.; Figueroa-Feliciano, E.; Goldfinger, D.; Wikus, P.; McCammon, D.; Oakley, P.

    2016-08-01

    Micro-X is a NASA-funded sounding rocket-borne X-ray imaging spectrometer designed to enable high precision measurements of extended astrophysical systems. To perform high energy resolution measurements and capture unprecedented spectra of supernova remnants and galaxy clusters, Micro-X must maintain tight temperature control. One of the biggest challenges in payload design is to prevent heating of the detectors due to the vibrational loads on the rocket skin during launch. Several stages of vibration damping systems are implemented to prevent energy transmission from the rocket skin to the detector stage, each stage more rigid than the last. We describe recent redesign efforts to improve this vibration isolation by tuning the resonant frequencies of the various stages to minimize heating prior to the projected launch in 2016.

  10. Influence of regenerator void volume on performance of a precooled 4 K Stirling type pulse tube cryocooler

    Science.gov (United States)

    Li, Zhuopei; Jiang, Yanlong; Gan, Zhihua; Qiu, Limin; Chen, Jie

    2015-09-01

    Stirling type pulse tube cryocoolers (SPTC), typically operating at 30-60 Hz, have the advantage of compact structure, light weight, and long life compared with Gifford-McMahon type (1-2 Hz) PTC (GMPTC). The behavior of flow and heat transfer in the regenerator of a 4 K SPTC deviates from that at warmer temperatures and low frequencies. In this paper the behavior of 4 K regenerator at high frequencies is investigated based on a single-stage 4 K SPTC precooled by a two-stage GMPTC. The 4 K SPTC and the GMPTC is thermally coupled with two thermal bridges. The 4 K SPTC uses a 10 K cold inertance tube as phase shifter to improve phase relationship between mass flow and pressure. The regenerator void volume is an important factor that significantly influences the heat transfer between regenerator matrix and working fluid helium, pressure drop along the regenerator, and phase shift between mass flow and pressure. In this paper, influence of regenerator void volume on the performance of the 4 K SPTC with different operating parameters including operating frequencies and average pressure is studied theoretically and experimentally. The first and second precooling powers provided by the GMPTC are obtained which are important parameters to evaluate the efficiency of the whole 4 K system with precooling. The results of the regenerator void volume are given and discussed in normalized form for general use.

  11. Performance of a 4 Kelvin pulse-tube cooled cryostat with dc SQUID amplifiers for bolometric detector testing

    CERN Document Server

    Barron, Darcy; Keating, Brian; Quillin, Ron; Stebor, Nathan; Wilson, Brandon

    2013-01-01

    The latest generation of cosmic microwave background (CMB) telescopes is searching for the undetected faint signature of gravitational waves from inflation in the polarized signal of the CMB. To achieve the unprecedented levels of sensitivity required, these experiments use arrays of superconducting Transition Edge Sensor (TES) bolometers that are cooled to sub-Kelvin temperatures for photon-noise limited performance. These TES detectors are read out using low- noise SQUID amplifiers. To rapidly test these detectors and similar devices in a laboratory setting, we constructed a cryogenic refrigeration chain consisting of a commercial two-stage pulse-tube cooler, with a base temperature of 3 K, and a closed-cycle 3He/4He/3He sorption cooler, with a base temperature of 220 mK. A commercial dc SQUID system, with sensors cooled to 4 K, was used as a highly-sensitive cryogenic ammeter. Due to the extreme sensitivity of SQUIDs to changing magnetic fields, there are several challenges involving cooling them with puls...

  12. The Role of Lithium Conditioning in Achieving High Performance, Long Pulse H-mode Discharges in the NSTX and EAST Devices

    Energy Technology Data Exchange (ETDEWEB)

    Maingi, Rajesh [PPPL; Mansfield, D. K. [PPPL; Gong, X. Z. [IPPCAS; Sun, Z. [IPPCAS; Bell, M. G. [PPPL

    2014-10-01

    In this paper, the role of lithium wall conditioning on the achievement of high performance, long pulse discharges in the National Spherical Torus Experiment (NSTX) and the Experimental Advanced Superconducting Tokamak (EAST) is documented. Common observations include recycling reduction and elimination of ELMs. In NSTX, lithium conditioning typically resulted in ELM-free operation with impurity accumulation, which was ameliorated e.g. with pulsed 3D fields to trigger controlled ELMs. Active lithium conditioning in EAST discharges has overcome this problem, producing an ELM-free Hmode with controlled density and impurities.

  13. Combustion and Magnetohydrodynamic Processes in Advanced Pulse Detonation Rocket Engines

    Science.gov (United States)

    2012-10-01

    an endothermic process, the parameter θa in this formulation is an averaged activation energy of the key radical-producing reactions. This is a...conserved variables, W = LQ, and by definition LR = RL = I. Now that the governing equations have been linearized with the pro- cess shown in Equation...Radulescu et al. attributed the stabilizing effect of the diluent to the lower temperature in the reaction zone which leads to slower exothermic reaction

  14. Water Rockets. Get Funny With Newton's Laws

    Directory of Open Access Journals (Sweden)

    Manuel Roca Vicent

    2017-01-01

    Full Text Available The study of the movement of the rocket has been used for decades to encourage students in the study of physics. This system has an undeniable interest to introduce concepts such as properties of gases, laws of Newton,  exchange  between  different  types  of  energy  and  its  conservation  or fluid  mechanics.  Our  works has  been  to  build  and  launch  these  rockets  in  different  educational  levels  and  in  each  of  these  ones  have introduced  the  part  of  Physics  more  suited  to  the  knowledge  of  our  students.  The  aim  of  the  learning experience  is  to  launch  the  rocket  as  far  as  possible  and  learn  to  predict  the  travelled  distance,  using Newton's  laws  and fluid  mechanics.  After  experimentation  we  demonstrated  to  be  able  to  control  the parameters that improve the performance of our rocket, such as the  fill factor, the volume and mass of the empty  bottle,  liquid  density,  launch  angle,  pressure  prior  air  release.  In addition, it is a fun experience can be attached to all levels of education in primary and high school.

  15. Performance Analysis of High-speed Optical Pulse Transmission in Dispersion-managed Nonlinear Birefringent Fiber Using Quantum Well Laser Diode Sources

    Institute of Scientific and Technical Information of China (English)

    YAN Minhui; CHEN Jianping

    2002-01-01

    This paper analyzes the high bit-rate optical pulse trasmission in single mode optical fiber with chromatic dispersion, polarization mode dispersion (small random birefringence) and nonlinearity. Numerical method employed can precisely describe their interactive effect on transmission performance. Different dispersion maps and the related performance are analysed. Various simulation results and discussion are given. The results show that chromatic dispersion compensation should be carefully designed. Appropriate dispersion management can also alleviate the effect of polarization mode dispersion.

  16. Unique nuclear thermal rocket engine

    Energy Technology Data Exchange (ETDEWEB)

    Culver, D.W. (Aerojet Propulsion Division, P.O. Box 13222, Sacramento, California 95813-6000 (United States)); Rochow, R. (Babcock Wilcox Space Nuclear Systems, P.O. Box 11165, Lynchburg, Virginia 24506-1165 (United States))

    1993-01-15

    Earlier this year Aerojet Propulsion Division (APD) introduced a new, advanced nuclear thermal rocket engine (NTRE) concept intended for manned missions to the moon and to Mars. This NTRE promises to be both shorter and lighter in weight than conventionally designed engines, because its forward flowing reactor is located within an expansion-deflection (E-D) rocket nozzle. The concept has matured during the year, and this paper discusses a nearer term version that resolves four open issues identified in the initial concept: (1)Reactor design and cooling scheme simplification while retaining a high pressure power balance option; (2)Eliminate need for a new, uncooled nozzle throat material suitable for long life application; (3)Practical provision for reactor power control; and (4)Use near term, long life turbopumps.

  17. Unique nuclear thermal rocket engine

    Science.gov (United States)

    Culver, Donald W.; Rochow, Richard

    1993-06-01

    In January, 1992, a new, advanced nuclear thermal rocket engine (NTRE) concept intended for manned missions to the moon and to Mars was introduced (Culver, 1992). This NTRE promises to be both shorter and lighter in weight than conventionally designed engines, because its forward flowing reactor is located within an expansion-deflection rocket nozzle. The concept has matured during the year, and this paper discusses a nearer term version that resolves four open issues identified in the initial concept: (1) the reactor design and cooling scheme simplification while retaining a high pressure power balance option; (2) elimination need for a new, uncooled nozzle throat material suitable for long life application; (3) a practical provision for reactor power control; and (4) use of near-term, long-life turbopumps.

  18. Extended temperature range rocket injector

    Science.gov (United States)

    Schneider, Steven J. (Inventor)

    1991-01-01

    A rocket injector is provided with multiple sets of manifolds for supplying propellants to injector elements. Sensors transmit the temperatures of the propellants to a suitable controller which is operably connnected to valves between these manifolds and propellant storage tanks. When cryogenic propellant temperatures are sensed, only a portion of the valves are opened to furnish propellants to some of the manifolds. When lower temperatures are sensed, additional valves are opened to furnish propellants to more of the manifolds.

  19. Mini-Rocket User Guide

    Science.gov (United States)

    2007-08-01

    Missile Research , Development, and Engineering Center and Ray Sells DESE Research , Inc. 315 Wynn Drive Huntsville, AL 35805 August 2007...with the minirock command, you are prompted for a filename: Mini-Rocket v1.01 by Ray Sells, DESE Research , Inc. Input file: - Output is printed...nancv.bucher@us.army.mil Commander, U.S. Army ARDEC Picatinny Arsenal, NJ 07806-5000 ATTN: AMSRD-AR-AIS -SA DESE Research , Inc. 3 15 Wynn Drive

  20. Optimization Problem of Multistage Rocket

    Directory of Open Access Journals (Sweden)

    V. B. Tawakley

    1972-04-01

    Full Text Available The necessary conditions for the existence of minimum of a function of initial and final values of mass, position and velocity components and time of a multistage rocket have been reviewed when the thrust levels in each stage are considered to bounded and variation in gravity with height has been taken into account. The nature of the extremal subarcs comprising the complete extremal are has been studied. A few simple examples have been given as illustrations.

  1. Physiological and phytosanitary potential of rocket seeds

    Directory of Open Access Journals (Sweden)

    Jucilayne Fernandes Vieira

    2015-02-01

    Full Text Available The objective of this study was to evaluate the physiological and sanitary quality of seeds of rocket; the research was done at the Laboratory of Seed Analysis and greenhouse of the Department of Plant Science, Federal University of Pelotas (UFPel. Four lots of the cultivar "Antonella'' were tested for following features: initial and final moisture content, germination rate, first count of germination, accelerated aging with saline solution, dry matter contents, seedling shoot and root length, emergence speed index, emergence of seedlings in substrate, electrical conductivity and sanitary condition. A completely randomized design with four replications was used for all tests done and means were compared by Tukey test (P≤0.05. For all tests performed it was concluded that despite changes in the ranking of the best lots, there was agreement regarding the indication of the inferiority of the lot 3 in all tests and it was also observed that the incidence of fungi associated with seeds of rocket interfere with the physiological quality of the lots.

  2. Computational simulation of liquid fuel rocket injectors

    Science.gov (United States)

    Landrum, D. Brian

    1994-01-01

    A major component of any liquid propellant rocket is the propellant injection system. Issues of interest include the degree of liquid vaporization and its impact on the combustion process, the pressure and temperature fields in the combustion chamber, and the cooling of the injector face and chamber walls. The Finite Difference Navier-Stokes (FDNS) code is a primary computational tool used in the MSFC Computational Fluid Dynamics Branch. The branch has dedicated a significant amount of resources to development of this code for prediction of both liquid and solid fuel rocket performance. The FDNS code is currently being upgraded to include the capability to model liquid/gas multi-phase flows for fuel injection simulation. An important aspect of this effort is benchmarking the code capabilities to predict existing experimental injection data. The objective of this MSFC/ASEE Summer Faculty Fellowship term was to evaluate the capabilities of the modified FDNS code to predict flow fields with liquid injection. Comparisons were made between code predictions and existing experimental data. A significant portion of the effort included a search for appropriate validation data. Also, code simulation deficiencies were identified.

  3. Advanced materials for radiation-cooled rockets

    Science.gov (United States)

    Reed, Brian; Biaglow, James; Schneider, Steven

    1993-01-01

    The most common material system currently used for low thrust, radiation-cooled rockets is a niobium alloy (C-103) with a fused silica coating (R-512A or R-512E) for oxidation protection. However, significant amounts of fuel film cooling are usually required to keep the material below its maximum operating temperature of 1370 C, degrading engine performance. Also the R-512 coating is subject to cracking and eventual spalling after repeated thermal cycling. A new class of high-temperature, oxidation-resistant materials are being developed for radiation-cooled rockets, with the thermal margin to reduce or eliminate fuel film cooling, while still exceeding the life of silicide-coated niobium. Rhenium coated with iridium is the most developed of these high-temperature materials. Efforts are on-going to develop 22 N, 62 N, and 440 N engines composed of these materials for apogee insertion, attitude control, and other functions. There is also a complimentary NASA and industry effort to determine the life limiting mechanisms and characterize the thermomechanical properties of these materials. Other material systems are also being studied which may offer more thermal margin and/or oxidation resistance, such as hafnium carbide/tantalum carbide matrix composites and ceramic oxide-coated iridium/rhenium chambers.

  4. Lunar mission design using Nuclear Thermal Rockets

    Science.gov (United States)

    Stancati, Michael L.; Collins, John T.; Borowski, Stanley K.

    1991-01-01

    The NERVA-class Nuclear Thermal Rocket (NTR), with performance nearly double that of advanced chemical engines, has long been considered an enabling technology for human missions to Mars. NTR engines address the demanding trip time and payload delivery needs of both cargo-only and piloted flights. But NTR can also reduce the Earth launch requirements for manned lunar missions. First use of NTR for the Moon would be less demanding and would provide a test-bed for early operations experience with this powerful technology. Study of application and design options indicates that NTR propulsion can be integrated with the Space Exploration Initiative scenarios to deliver performance gains while managing controlled, long-term disposal of spent reactors to highly stable orbits.

  5. Space shuttle with common fuel tank for liquid rocket booster and main engines (supertanker space shuttle)

    Science.gov (United States)

    Thorpe, Douglas G.

    1991-01-01

    An operation and schedule enhancement is shown that replaces the four-body cluster (Space Shuttle Orbiter (SSO), external tank, and two solid rocket boosters) with a simpler two-body cluster (SSO and liquid rocket booster/external tank). At staging velocity, the booster unit (liquid-fueled booster engines and vehicle support structure) is jettisoned while the remaining SSO and supertank continues on to orbit. The simpler two-bodied cluster reduces the processing and stack time until SSO mate from 57 days (for the solid rocket booster) to 20 days (for the liquid rocket booster). The areas in which liquid booster systems are superior to solid rocket boosters are discussed. Alternative and future generation vehicles are reviewed to reveal greater performance and operations enhancements with more modifications to the current methods of propulsion design philosophy, e.g., combined cycle engines, and concentric propellant tanks.

  6. Enhanced performance of an EUV light source (λ = 84 nm) using short-pulse excitation of a windowless dielectric barrier discharge in neon

    Science.gov (United States)

    Carman, R. J.; Kane, D. M.; Ward, B. K.

    2010-01-01

    The electrical and optical characteristics of a dielectric barrier discharge (DBD) based neon excimer lamp generating output in the extreme ultraviolet (EUV) spectral range (λ = 84 nm) have been investigated experimentally. We report a detailed comparison of lamp performance for both pulsed and sinusoidal voltage excitation waveforms, using otherwise identical operating conditions. The results show that pulsed voltage excitation yields a ~50% increase in the overall electrical to EUV conversion efficiency compared with sinusoidal waveforms, when operating in the pressure range 500-900 mbar. Pulsed operation allows greater control of parameters associated with the temporal evolution of the EUV pulse shapes (risetime, instantaneous peak power). The Ne DBD based source is also found to be highly monochromatic with respect to its spectral output from the second continuum band at λ ~ 84 nm (5 nm FWHM). This continuum band dominates the spectral emission over the wavelength range 30-550 nm. Lamp performance; as measured by the overall EUV output energy, electrical to EUV conversion efficiency and spectral purity at λ ~ 84 nm; improves with increasing gas pressure up to p = 900 mbar.

  7. Enhanced performance of an EUV light source ({lambda} = 84 nm) using short-pulse excitation of a windowless dielectric barrier discharge in neon

    Energy Technology Data Exchange (ETDEWEB)

    Carman, R J; Kane, D M; Ward, B K, E-mail: rcarman@science.mq.edu.a [Department of Physics and Engineering, Faculty of Science, Macquarie University, North Ryde, Sydney, NSW 2109 (Australia)

    2010-01-20

    The electrical and optical characteristics of a dielectric barrier discharge (DBD) based neon excimer lamp generating output in the extreme ultraviolet (EUV) spectral range ({lambda} = 84 nm) have been investigated experimentally. We report a detailed comparison of lamp performance for both pulsed and sinusoidal voltage excitation waveforms, using otherwise identical operating conditions. The results show that pulsed voltage excitation yields a {approx}50% increase in the overall electrical to EUV conversion efficiency compared with sinusoidal waveforms, when operating in the pressure range 500-900 mbar. Pulsed operation allows greater control of parameters associated with the temporal evolution of the EUV pulse shapes (risetime, instantaneous peak power). The Ne DBD based source is also found to be highly monochromatic with respect to its spectral output from the second continuum band at {lambda} {approx} 84 nm (5 nm FWHM). This continuum band dominates the spectral emission over the wavelength range 30-550 nm. Lamp performance; as measured by the overall EUV output energy, electrical to EUV conversion efficiency and spectral purity at {lambda} {approx} 84 nm; improves with increasing gas pressure up to p = 900 mbar.

  8. Electro-stimulation of Saccharomyces cerevisiae wine yeasts by Pulsed Electric Field and its effect on fermentation performance

    CERN Document Server

    Mattar, J; Nonus, M; Lebovka, N I; Zakhem, H El; Vorobiev, E

    2013-01-01

    The batch fermentation process, inoculated by pulsed electric field (PEF) treated wine yeasts (S. cerevisiae Actiflore F33), was studied. PEF treatment was applied to the aqueous yeast suspensions (0.12 % wt.) at the electric field strengths of E=100 and 6000 V/cm using the same pulse protocol (number of pulses of n=1000, pulse duration of ti=100 mks, and pulse repetition time of dt=100 ms). Electro-stimulation was confirmed by the observed growth of electrical conductivity of suspensions. The fermentation was running at 30{\\deg}C for 150 hours in an incubator with synchronic agitation. The obtained results clearly evidence the positive impact of PEF treatment on the batch fermentation process. Electro-stimulation resulted in improvement of such process characteristics as mass losses, consumption of soluble matter content ({\\deg}Brix) and synthesis of proteins. It also resulted in a noticeable acceleration of consumption of sugars at the initial stage of fermentation in the lag phase. At the end of the lag ph...

  9. Studies of solid propellant combustion with pulsed radiography

    Science.gov (United States)

    Godai, T.; Tanemura, T.; Fujiwara, T.; Shimizu, M.

    1987-01-01

    Pulsed radiography was applied to observe solid propellant surface regression during rocket motor operation. Using a 150 KV flash X-ray system manufactured by the Field Emission Corporation and two kinds of film suppliers, images of the propellant surface of a 5 cm diameter end burning rocket motor were recorded on film. The repetition frame rate of 8 pulses per second and the pulse train length of 10 pulses are limited by the capability of the power supply and the heat build up within the X-ray tube, respectively. The experiment demonstrated the effectiveness of pulsed radiography for observing solid propellant surface regression. Measuring the position of burning surface images on film with a microdensitometer, quasi-instantaneous burning rate as a function of pressure and the variation of characteristic velocity with pressure and gas stay time were obtained. Other research items to which pulsed radiography can be applied are also suggested.

  10. A NEW EFFICIENT METHOD TO BOUNDARY VALUE PROBLEM FOR BALLISTIC ROCKET GUIDANCE

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The exploitation of rocket guidance technology on the basis of the guidance law of Space Shuttle and Pegasus rocket was performed. A new efficient method of numerical iteration solution to the boundary value problem was put forward. The numerical simulation results have shown that the method features good performances of stability, robustness, high precision, and algebraic formulas in real computation. By virtue of modern DSP (digital signal processor) high speed chip technology, the algorithm can be used in real time and can adapt to the requirements of the big primary bias of rocket guidance.

  11. Study of Rapid-Regression Liquefying Hybrid Rocket Fuels

    Science.gov (United States)

    Zilliac, Greg; DeZilwa, Shane; Karabeyoglu, M. Arif; Cantwell, Brian J.; Castellucci, Paul

    2004-01-01

    A report describes experiments directed toward the development of paraffin-based hybrid rocket fuels that burn at regression rates greater than those of conventional hybrid rocket fuels like hydroxyl-terminated butadiene. The basic approach followed in this development is to use materials such that a hydrodynamically unstable liquid layer forms on the melting surface of a burning fuel body. Entrainment of droplets from the liquid/gas interface can substantially increase the rate of fuel mass transfer, leading to surface regression faster than can be achieved using conventional fuels. The higher regression rate eliminates the need for the complex multi-port grain structures of conventional solid rocket fuels, making it possible to obtain acceptable performance from single-port structures. The high-regression-rate fuels contain no toxic or otherwise hazardous components and can be shipped commercially as non-hazardous commodities. Among the experiments performed on these fuels were scale-up tests using gaseous oxygen. The data from these tests were found to agree with data from small-scale, low-pressure and low-mass-flux laboratory tests and to confirm the expectation that these fuels would burn at high regression rates, chamber pressures, and mass fluxes representative of full-scale rocket motors.

  12. Reusable rocket engine optical condition monitoring

    Science.gov (United States)

    Wyett, L.; Maram, J.; Barkhoudarian, S.; Reinert, J.

    1987-01-01

    Plume emission spectrometry and optical leak detection are described as two new applications of optical techniques to reusable rocket engine condition monitoring. Plume spectrometry has been used with laboratory flames and reusable rocket engines to characterize both the nominal combustion spectra and anomalous spectra of contaminants burning in these plumes. Holographic interferometry has been used to identify leaks and quantify leak rates from reusable rocket engine joints and welds.

  13. Regeneratively-Cooled, Turbopump-Fed, Small-Scale Cryogenic Rocket Engines Project

    Data.gov (United States)

    National Aeronautics and Space Administration — To-date, the realization of small-scale, high-performance liquid bipropellant rocket engines has largely been limited by the inability to operate at high chamber...

  14. Simulation methods of rocket fuel refrigerating with liquid nitrogen and intermediate heat carrier

    National Research Council Canada - National Science Library

    O. E. Denisov; A. V. Zolin; V. V. Chugunkov

    2014-01-01

    Temperature preparation of liquid propellant components (LPC) before fueling the tanks of rocket and space technology is the one of the operations performed by ground technological complexes on cosmodromes...

  15. Investigating the performances of a 1 MV high pulsed power linear transformer driver: from beam dynamics to x radiation

    Directory of Open Access Journals (Sweden)

    R. Maisonny

    2016-12-01

    Full Text Available The performance of a 1 MV pulsed high-power linear transformer driver accelerator were extensively investigated based on a numerical approach which utilizes both electromagnetic and Monte Carlo simulations. Particle-in-cell calculations were employed to examine the beam dynamics throughout the magnetically insulated transmission line which governs the coupling between the generator and the electron diode. Based on the information provided by the study of the beam dynamics, and using Monte Carlo methods, the main properties of the resulting x radiation were predicted. Good agreement was found between these simulations and experimental results. This work provides a detailed understanding of mechanisms affecting the performances of this type of high current, high-voltage pulsed accelerator, which are very promising for a growing number of applications.

  16. NERVA-Derived Concept for a Bimodal Nuclear Thermal Rocket

    Science.gov (United States)

    Fusselman, Steven P.; Borowski, Stanley K.; Frye, Patrick E.; Gunn, Stanley V.; Morrison, Calvin Q.

    2005-02-01

    The Nuclear Thermal Rocket is an enabling technology for human exploration missions. The "bimodal" NTR (BNTR) provides a novel approach to meeting both propulsion and power requirements of future manned and robotic missions. The purpose of this study was to evaluate tie-tube cooling configurations, NTR performance, Brayton cycle performance, and LOX-Augmented NTR (LANTR) feasibility to arrive at a point of departure BNTR configuration for subsequent system definition.

  17. Rocket Engine Innovations Advance Clean Energy

    Science.gov (United States)

    2012-01-01

    During launch countdown, at approximately T-7 seconds, the Space Shuttle Main Engines (SSMEs) roar to life. When the controllers indicate normal operation, the solid rocket boosters ignite and the shuttle blasts off. Initially, the SSMEs throttle down to reduce stress during the period of maximum dynamic pressure, but soon after, they throttle up to propel the orbiter to 17,500 miles per hour. In just under 9 minutes, the three SSMEs burn over 1.6 million pounds of propellant, and temperatures inside the main combustion chamber reach 6,000 F. To cool the engines, liquid hydrogen circulates through miles of tubing at -423 F. From 1981to 2011, the Space Shuttle fleet carried crew and cargo into orbit to perform a myriad of unprecedented tasks. After 30 years and 135 missions, the feat of engineering known as the SSME boasted a 100-percent flight success rate.

  18. Innovative Metallized Formulations for Solid Rocket Propulsion

    Institute of Scientific and Technical Information of China (English)

    Luigi T DeLUCA; Luciano GALFETTI; Filippo MAGGI; Giovanni COLOMBO; Alice REINA; Stefano DOSSI; Daniele CONSONNI; Melissa BRAMBILLA

    2012-01-01

    Several metallized solid rocket propellants,AP/Metal/HTPB in the ratio 68/18/1 4,were experimentally analyzed at the Space Propulsion Laboratory of Politecnico di Milano.Effects of the metals (micrometric and nanometric Al,B,Mg,and a variety of dual metals) on the performance of the propellant were studied and contrasted to a conventional micrometric aluminum (30 μm average grain size) taken as reference.It is shown that the propellant microstructure plays a fundamental role in controlling the critical aggregation/agglomeration phenomena occurring below and near the burning surface.Two specific effects of microstructure in terms of steady burning rate and average agglomerate size are illustrated.

  19. Liquid atomization by coaxial rocket injectors

    Science.gov (United States)

    Sankar, S. V.; Brena De La Rosa, A.; Isakovic, A.; Bachalo, W. D.

    1991-01-01

    The atomization characteristics of a scaled-down version of a coaxial rocket injector was investigated using a phase Doppler particle analyzer (PDPA). The injector was operated in the conventional mode with liquid being injected through its inner orifice and gas being injected through its outer annulus. The shearing action occurring at the liquid-gas interface causes the liquid jet to atomize. In this study, two different liquid-air systems, namely a water-air system and a liquid nitrogen-gaseous nitrogen system, were chosen for detailed investigation. This paper discusses the performance characteristics of the coaxial injector under different flow and geometric conditions. Specifically, the effects of injection gas pressure and the injector cavity size on variables such as the mean particle diameter, Sauter mean diameter, number density, volume flux, and velocity have been presented.

  20. Demilitarization of Lance rocket motors

    Science.gov (United States)

    Sargent, Peter

    1995-02-01

    In 1992 Royal Ordnance was awarded contract by NAMSA for the demilitarization of NATO's European stock of Lance missile rocket motors. Lance is a liquid fueled surface to surface guided missile designed to give general battlefield support with either a nuclear or conventional capability at ranges of up to 130 km. The NAMSA contract required Royal Ordnance to undertake the following: (1) transportation of missiles from NATO depots in Europe to Royal Ordnance's factory at Bishopton in Scotland; (2) establishment of a dedicated demilitarization facility at Bishopton; and (3) demilitarization of live M5 and M6 training missiles by the end of 1994.

  1. The Advanced Solid Rocket Motor

    Science.gov (United States)

    Mitchell, Royce E.

    1992-08-01

    The Advanced Solid Rocket Motor will utilize improved design features and automated manufacturing methods to produce an inherently safer propulsive system for the Space Shuttle and future launch systems. This second-generation motor will also provide an additional 12,000 pounds of payload to orbit, enhancing the utility and efficiency of the Shuttle system. The new plant will feature strip-wound, asbestos-free insulation; propellant continuous mixing and casting; and extensive robotic systems. Following a series of static tests at the Stennis Space Center, MS flights are targeted to begin in early 1997.

  2. The Advanced Solid Rocket Motor

    Science.gov (United States)

    Mitchell, Royce E.

    1992-01-01

    The Advanced Solid Rocket Motor will utilize improved design features and automated manufacturing methods to produce an inherently safer propulsive system for the Space Shuttle and future launch systems. This second-generation motor will also provide an additional 12,000 pounds of payload to orbit, enhancing the utility and efficiency of the Shuttle system. The new plant will feature strip-wound, asbestos-free insulation; propellant continuous mixing and casting; and extensive robotic systems. Following a series of static tests at the Stennis Space Center, MS flights are targeted to begin in early 1997.

  3. One-Stage and Two-Stage Schemes of High Performance Synchronous PWM with Smooth Pulses-Ratio Changing

    DEFF Research Database (Denmark)

    Oleschuk, V.; Blaabjerg, Frede

    2002-01-01

    modulation with synchronization of the voltage waveform of the inverter and with smooth pulse-ratio changing. Voltage spectra do not contain even harmonic and sub-harmonics (combined harmonics) during the whole control range including the zone of overmodulation. Examples of determination of the basic control...

  4. A Green, Safe, Dual-pulse Solid Motor for CubeSat Orbit Changing Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Small satellites such as CubeSats are in need of responsive propulsion, but are limited due to their size. Though single pulse, AP/HTPB fueled solid rocket motors...

  5. Ionospheric effects of whistler waves from rocket-triggered lightning

    Science.gov (United States)

    Cotts, B. R. T.; Gołkowski, M.; Moore, R. C.

    2011-12-01

    Lightning-induced electron precipitation (LEP) is one of the primary mechanisms for energetic electron loss from Earth's radiation belts. While previous works have emphasized lightning location and the return stroke peak current in quantifying lightning's role in radiation belt electron loss, the spectrum of the lightning return stroke has received far less attention. Rocket-triggered lightning experiments performed at the International Center for Lightning Research and Testing (ICLRT) at Camp Blanding, Florida, provide a means to directly measure the spectral content of individual lightning return strokes. Using an integrated set of numerical models and directly observed rocket-triggered lightning channel-base currents we calculate the latitudinal dependence of the precipitation signature. Model results indicate that rocket-triggered lightning may produce detectable LEP events and that return strokes with higher ELF (3 Hz-3 kHz) content cause proportionally more ionospheric ionization and precipitate more electrons at higher latitudes than return strokes with proportionally higher VLF (3 kHz-30 kHz) content. The predicted spatio-temporal signature of the induced electron precipitation is highly dependent upon the return stroke spectral content. As a result, we postulate that rocket-triggered lightning experiments enable us to the estimate the spectral profile of energetic electrons precipitated from the Earth's radiation belts.

  6. Metallic hydrogen: The most powerful rocket fuel yet to exist

    Energy Technology Data Exchange (ETDEWEB)

    Silvera, Isaac F [Lyman Laboratory of Physics, Harvard University, Cambridge MA 02138 (United States); Cole, John W, E-mail: silvera@physics.harvard.ed [NASA MSFC, Huntsville, AL 35801 (United States)

    2010-03-01

    Wigner and Huntington first predicted that pressures of order 25 GPa were required for the transition of solid molecular hydrogen to the atomic metallic phase. Later it was predicted that metallic hydrogen might be a metastable material so that it remains metallic when pressure is released. Experimental pressures achieved on hydrogen have been more than an order of magnitude higher than the predicted transition pressure and yet it remains an insulator. We discuss the applications of metastable metallic hydrogen to rocketry. Metastable metallic hydrogen would be a very light-weight, low volume, powerful rocket propellant. One of the characteristics of a propellant is its specific impulse, I{sub sp}. Liquid (molecular) hydrogen-oxygen used in modern rockets has an Isp of {approx}460s; metallic hydrogen has a theoretical I{sub sp} of 1700s. Detailed analysis shows that such a fuel would allow single-stage rockets to enter into orbit or carry economical payloads to the moon. If pure metallic hydrogen is used as a propellant, the reaction chamber temperature is calculated to be greater than 6000 K, too high for currently known rocket engine materials. By diluting metallic hydrogen with liquid hydrogen or water, the reaction temperature can be reduced, yet there is still a significant performance improvement for the diluted mixture.

  7. Studies of an extensively axisymmetric rocket based combined cycle (RBCC) engine powered single-stage-to-orbit (SSTO) vehicle

    Science.gov (United States)

    Foster, Richard W.; Escher, William J. D.; Robinson, John W.

    1989-01-01

    The present comparative performance study has established that rocket-based combined cycle (RBCC) propulsion systems, when incorporated by essentially axisymmetric SSTO launch vehicle configurations whose conical forebody maximizes both capture-area ratio and total capture area, are capable of furnishing payload-delivery capabilities superior to those of most multistage, all-rocket launchers. Airbreathing thrust augmentation in the rocket-ejector mode of an RBCC powerplant is noted to make a major contribution to final payload capability, by comparison to nonair-augmented rocket engine propulsion systems.

  8. Influence of gunpowder start system on starting performance of liquid rocket engines%火药起动系统对发动机起动性能的影响分析

    Institute of Scientific and Technical Information of China (English)

    孙海雨; 刘志让

    2012-01-01

    Aiming at the pumping pressure open cycle liquid rocket engine which is started by solid start cartridge (SSC), the performance of the start system is studied in this paper. The simulated model of SSC in the start system and the numerical model of the powder gas pipeline were established to simulate the process of gunpowder start. The influence of SSC and gas pipeline parameters on start performance of engine is analyzed to ensure the main influence parameters and regular patterns. It is found that the powder quantity of SSC and the diameter of the first throat in the powder gas pipeline are the most effective factors to the engine's start characteristic. The diameter of the powder gas pipeline's second throat and the diameter of the powder gas pipeline's outlet are the least ones in the case of that the powder gas pipeline's flow field keeps rated condition. The simulated result of the start system was proven in engine hot tests.%针对采用火药起动器起动的泵压开式循环液体火箭发动机,对其起动系统进行了分析和研究。建立了液体火箭发动机火药起动器计算模型和起动系统燃气管路流场计算模型。将所建立的起动系统模型应用于发动机系统仿真,对发动机火药起动过程进行仿真,分析了起动系统中火药起动器参数和燃气管路参数对发动机起动性能的影响,确定了主要影响参数和影响规律。火药起动器火药药柱内径、火药药柱长度以及燃气管路火药起动器喷管喉部直径为强影响因素;燃气管路涡轮喷嘴喉部直径和管路出口直径在确保发动机火药起动主要工况段燃气管路流场流态为额定工况流态的前提下,为弱影响因素。试验数据验证表明,发动机起动系统的仿真结果正确、可信。

  9. Combustion oscillation study in a kerosene fueled rocket-based combined-cycle engine combustor

    Science.gov (United States)

    Huang, Zhi-Wei; He, Guo-Qiang; Qin, Fei; Xue, Rui; Wei, Xiang-Geng; Shi, Lei

    2016-12-01

    This study reports the combustion oscillation features in a three-dimensional (3D) rocket-based combined-cycle (RBCC) engine combustor under flight Mach number (Mflight) 3.0 conditions both experimentally and numerically. Experiment is performed on a direct-connect ground test facility, which measures the wall pressure along the flow-path. High-speed imaging of the flame luminosity and schlieren is carried out at exit of the primary rocket. Compressible reactive large eddy simulation (LES) with reduced chemical kinetics of a surrogate model for kerosene is performed to further understand the combustion oscillation mechanisms in the combustor. LES results are validated with experimental data by the time-averaged and root mean square (RMS) pressure values, and show acceptable agreement. Effects of the primary rocket jet on pressure oscillation in the combustor are analyzed. Relation of the high speed rocket jet oscillation, which is thought to among the most probable sources of combustion oscillation, with the RBCC combustor is recognized. Results reveal that the unsteady over-expanded rocket jet has significant impacts on the combustion oscillation feature of the RBCC combustor, which is different from a thermo-acoustics type oscillation. The rocket jet/air inflow physical interactions under different rocket jet expansion degrees are experimentally studied.

  10. A novel strategy combining magnetic particle hyperthermia pulses with enhanced performance binary ferrite carriers for effective in vitro manipulation of primary human osteogenic sarcoma cells.

    Science.gov (United States)

    Makridis, Antonios; Tziomaki, Magdalini; Topouridou, Konstantina; Yavropoulou, Maria P; Yovos, John G; Kalogirou, Orestis; Samaras, Theodoros; Angelakeris, Mavroeidis

    2016-11-01

    The present study examines the heating efficiency of a combination of manganese or cobalt ferrites in a binary (Co- or Mn-) ferrite nanoparticle form with magnetite, covered with citric acid to improve biocompatibility. The nanoparticle synthesis is based on the aqueous co-precipitation of proper salts, a facile, low-cost, environmentally friendly and high yield synthetic approach. By detailed structural and magnetic characterisation, the direct influence of structural and magnetic features on magnetic hyperthermia concludes to optimum heating efficiency. At a second stage, best performing magnetic nanoparticles undergo in vitro testing in three cell lines: one cancer cell line and two reference healthy cell lines. Both binary ferrite (MnFe2O4/Fe3O4 and CoFe2O4/Fe3O4) appear to be internalised and well tolerated by the cells while a versatile hyperthermia protocol is attempted in an effort to further improve their in vitro performance. Within this protocol, hyperthermia sequences are split in two runs with an intermediate 48 h time interval cell incubation stage while in each run a variable field mode (single or multiple pulses) is applied. Single-pulse field mode represents a typical hyperthermia application scheme where cells undergo the thermal shock continuously. On the other hand multiple-pulses mode refers to multiple, much shorter in duration AC field changes (field ON/OFFs), at each hyperthermia run, resulting eventually in high heating rate and much more harmful cell treatment. Consequently, we propose a novel series of improved performance heat mediators based on ferrite structures which show maximum efficiency at cancer cells when combined with a versatile multiple-pulse hyperthermia module.

  11. Performance verification and system integration tests of the pulse shape processor for the soft x-ray spectrometer onboard ASTRO-H

    Science.gov (United States)

    Takeda, Sawako; Tashiro, Makoto S.; Ishisaki, Yoshitaka; Tsujimoto, Masahiro; Seta, Hiromi; Shimoda, Yuya; Yamaguchi, Sunao; Uehara, Sho; Terada, Yukikatsu; Fujimoto, Ryuichi; Mitsuda, Kazuhisa

    2014-07-01

    The soft X-ray spectrometer (SXS) aboard ASTRO-H is equipped with dedicated digital signal processing units called pulse shape processors (PSPs). The X-ray microcalorimeter system SXS has 36 sensor pixels, which are operated at 50 mK to measure heat input of X-ray photons and realize an energy resolution of 7 eV FWHM in the range 0.3-12.0 keV. Front-end signal processing electronics are used to filter and amplify the electrical pulse output from the sensor and for analog-to-digital conversion. The digitized pulses from the 36 pixels are multiplexed and are sent to the PSP over low-voltage differential signaling lines. Each of two identical PSP units consists of an FPGA board, which assists the hardware logic, and two CPU boards, which assist the onboard software. The FPGA board triggers at every pixel event and stores the triggering information as a pulse waveform in the installed memory. The CPU boards read the event data to evaluate pulse heights by an optimal filtering algorithm. The evaluated X-ray photon data (including the pixel ID, energy, and arrival time information) are transferred to the satellite data recorder along with event quality information. The PSP units have been developed and tested with the engineering model (EM) and the flight model. Utilizing the EM PSP, we successfully verified the entire hardware system and the basic software design of the PSPs, including their communication capability and signal processing performance. In this paper, we show the key metrics of the EM test, such as accuracy and synchronicity of sampling clocks, event grading capability, and resultant energy resolution.

  12. Telemaxus: A telescience oriented sounding rocket experiment

    Science.gov (United States)

    Monti, R.; Fortezza, R.; Desiderio, G.; Capuano, G.; Titomanlio, D.

    Following the success of the Texus 23 Campaign (November 1989), during which the Teletexus experiment was conducted a more ambitious Telescience experiment was accomodated on the 1991 MAXUS 1 Payload. The fluidynamic experiment on the oscillatory Marangoni flow was performed on board the rocket (launched at Kiruna, Sweden) using a modified TEM-06/4 module. The experiment was fully controlled by the PI (Professor Monti) directly from the Telescience Control Room located at MARS Center (Naples, Italy). The experiment was also aimed to demonstrate the capabilities of Telescience Service that ESA offers to the European Microgravity User Community. Respect to other experiments already tested and assessed during previous Texus missions (14b, 23), the Telescience operation mode included new state-of-art technologies and subsystems to demonstrate capabilities, flexibility and usefulness of this operation concept mainly in the perspective of Columbus utilization. Unfortunately due to a failure of the rocket system, the microgravity condition was not reached during the flight and the fluidynamic results were missed. However, in spite of the tumbling attitude of the rocket, the telescience link was successfully tested and the video/data/audio communication was correctly established between MARS and Esrange. This paper illustrates the technological aspects and gives an overview of the systems/equipments integrated and realized for the experiment control. In the first part the H/W configurations for the experiment monitoring and control, identified by the research team are illustrated. The relevant items of the H/W configuration include: the Telescience Work Stations architecture, the link channels used for the selection, transmission and reception of video/data/commands and the subsystems manufactured to improve the system versatility. The second part deals with the communication link used for transmission between Sweden and Italy of experimental data, facility status, voice

  13. A pulse-compression-ring circuit for high-efficiency electric propulsion.

    Science.gov (United States)

    Owens, Thomas L

    2008-03-01

    A highly efficient, highly reliable pulsed-power system has been developed for use in high power, repetitively pulsed inductive plasma thrusters. The pulsed inductive thruster ejects plasma propellant at a high velocity using a Lorentz force developed through inductive coupling to the plasma. Having greatly increased propellant-utilization efficiency compared to chemical rockets, this type of electric propulsion system may one day propel spacecraft on long-duration deep-space missions. High system reliability and electrical efficiency are extremely important for these extended missions. In the prototype pulsed-power system described here, exceptional reliability is achieved using a pulse-compression circuit driven by both active solid-state switching and passive magnetic switching. High efficiency is achieved using a novel ring architecture that recovers unused energy in a pulse-compression system with minimal circuit loss after each impulse. As an added benefit, voltage reversal is eliminated in the ring topology, resulting in long lifetimes for energy-storage capacitors. System tests were performed using an adjustable inductive load at a voltage level of 3.3 kV, a peak current of 20 kA, and a current switching rate of 15 kA/micros.

  14. Solid Rocket Booster-Illustration

    Science.gov (United States)

    1977-01-01

    This illustration is a cutaway of the solid rocket booster (SRB) sections with callouts. The Shuttle's two SRB's are the largest solids ever built and the first designed for refurbishment and reuse. Standing nearly 150-feet high, the twin boosters provide the majority of thrust for the first two minutes of flight, about 5.8 million pounds, augmenting the Shuttle's main propulsion system during liftoff. The major design drivers for the solid rocket motors (SRM's) were high thrust and reuse. The desired thrust was achieved by using state-of-the-art solid propellant and by using a long cylindrical motor with a specific core design that allows the propellant to burn in a carefully controlled marner. At burnout, the boosters separate from the external tank and drop by parachute to the ocean for recovery and subsequent refurbishment. The boosters are designed to survive water impact at almost 60 miles per hour, maintain flotation with minimal damage, and preclude corrosion of the hardware exposed to the harsh seawater environment. Under the project management of the Marshall Space Flight Center, the SRB's are assembled and refurbished by the United Space Boosters. The SRM's are provided by the Morton Thiokol Corporation.

  15. Pulse Tube Refrigerator

    Science.gov (United States)

    Matsubara, Yoichi

    The pulse tube refrigerator is one of the regenerative cycle refrigerators such as Stirling cycle or Gifford-McMahon cycle which gives the cooling temperature below 150 K down to liquid helium temperature. In 1963, W. E. Gifford invented a simple refrigeration cycle which is composed of compressor, regenerator and simple tube named as pulse tube which gives a similar function of the expander in Stirling or Gifford-McMahon cycle. The thermodynamically performance of this pulse tube refrigerator is inferior to that of other regenerative cycles. In 1984, however, Mikulin and coworkers made a significant advance in pulse tube configuration called as orifice pulse tube. After this, several modifications of the pulse tube hot end configuration have been developed. With those modifications, the thermodynamic performance of the pulse tube refrigerator became the same order to that of Stirling and Gifford-McMahon refrigerator. This article reviews the brief history of the pulse tube refrigerator development in the view point of its thermodynamically efficiency. Simplified theories of the energy flow in the pulse tube have also been described.

  16. CFD Simulation of Liquid Rocket Engine Injectors

    Science.gov (United States)

    Farmer, Richard; Cheng, Gary; Chen, Yen-Sen; Garcia, Roberto (Technical Monitor)

    2001-01-01

    these investigators to be very valuable for code validation because combustion kinetics, turbulence models and atomization models based on low pressure experiments of hydrogen air combustion do not adequately verify analytical or CFD submodels which are necessary to simulate rocket engine combustion. We wish to emphasize that the simulations which we prepared for this meeting are meant to test the accuracy of the approximations used in our general purpose spray combustion models, rather than represent a definitive analysis of each of the experiments which were conducted. Our goal is to accurately predict local temperatures and mixture ratios in rocket engines; hence predicting individual experiments is used only for code validation. To replace the conventional JANNAF standard axisymmetric finite-rate (TDK) computer code 2 for performance prediction with CFD cases, such codes must posses two features. Firstly, they must be as easy to use and of comparable run times for conventional performance predictions. Secondly, they must provide more detailed predictions of the flowfields near the injector face. Specifically, they must accurately predict the convective mixing of injected liquid propellants in terms of the injector element configurations.

  17. Reducing Thrusts In Solid-Fuel Rockets

    Science.gov (United States)

    Bement, Laurence J.

    1989-01-01

    Thrust-terminating system conceived to reduce thrust of solid-propellant rocket motor in controlled manner such that thrust loads not increased or decreased beyond predictable levels. Concept involves explosively cutting opposing venting pairs in case of rocket motor above nozzles to initiate venting of chamber and reduction of thrust. Vents sized and numbered to control amount and rate of reduction in thrust.

  18. Effect of Nd3+ concentration on CW and pulsed performance of fiber-coupled diode laser pumped Nd:YVO4 laser at 1064 nm

    Indian Academy of Sciences (India)

    Pranab K Mukhopadhyay; K Ranganathan; Jogy George; S K Sharma; T P S Nathan

    2002-07-01

    The effect of Nd3+ concentration on the CW and Q-switched laser performances at 1064 nm from Nd : YVO4 has been studied under diode laser pumping in identical laser configuration. The Nd3+ concentrations used were 1, 2 and 3 at. % in YVO4 crystals. Under the CW operations we have compared the thermal lensing effect, slope efficiencies and also the beam quality at the fourth-order degeneracy configuration. Q-switching was done with the help of an acousto-optic modulator and we have compared the pulses obtained from Nd : YVO4 laser with different doping concentration. It was found that the 1 at.%-doped crystal is the best, offering highest optical-to-optical conversion efficiency (55%), lowest fractional heat load (24%), highest pulse energy (80 J) and shortest pulse width (20 ns). It was also found that there was not much difference in performances for 2 and 3 at. %-doped crystals both in CW and Q-switched configurations.

  19. Time of Arrival Based on Chirp Pulses as a means to Perform Localization in IEEE 802.15.4a Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    NAUWELAERS, B.

    2010-05-01

    Full Text Available This paper introduces the technology Time of Arrival (TOA based on chirp pulses (according to IEEE 802.15.4a as a means to perform localization in Wireless Sensor Networks (WSN's active at 2.4 GHz. Advantages and disadvantages of the technology are discussed and act as a guideline for improving localization accuracy. Tests concerning TOA are performed by means of the location engine of Nanotron. Adapting this engine leads to improved localization results. It is shown that TOA measurements are susceptible to reflections and dynamic environments.

  20. Enhanced performance of a repetitively pulsed 130 mJ KrF laser with improved pre-ionization parameters

    Indian Academy of Sciences (India)

    N S Benerji; A Singh; N Varshnay; Bijendra Singh

    2014-01-01

    Studies related to the effect of pre-ionizer on laser output energy of a repetitively pulsed KrF laser are presented. The dependence of laser output energy, spectral width and beam spot homogeneity on pre-ionization parameters, namely its current and voltage rise time are reported here. Here, effectiveness of pre-ionization is optimized by improving pre-ionization current and rise time of the pump pulse of the automatic UV pre-ionizer KrF laser. It is observed that by increasing pre-ionization current from 6 kA to 10.6 kA, the output energy increases by about 30% (from 100 to 130 mJ). It is also observed that the emission spectral width reduces by almost 60% by increasing the pre-ionization current. Regular homogeneous and well-developed beam spot (nearly Hat-Top profile) was achieved under these optimized conditions.

  1. Effect of High Electric Field on Lifetime Performance of Metalized Film Capacitor in Pulsed-power Applications

    Institute of Scientific and Technical Information of China (English)

    LI Hua; CHEN Yaohong; WANG Bowen; LI Zhiwei; ZHANG Qin; LIN Fuchang; HE Wei

    2013-01-01

    High energy density capacitor is a key device to power supply source for electromagnetic gun (EMG) system,and extending its lifetime is important for increasing the reliability of the power source.Working in high electric field could affect the capacitor lifetime,and this effect on metallized polypropylene film capacitors (MPPFCs) in pulsed-power applications is studied and presented.Experimental results show that the lifetime of MPPFCs decreases with the increasing peak value of charged electric field,and this decrease could be described by function (L/L0) ∝ (E/E0)-m,where,m=7.32.The lifetime of MPPFCs also decreases with the increase of the reversal coefficients in underdamped circuits,which could be described by (L/L0) ∝ (ln(1/K0)/(ln(1/K))-b,where,b=0.7.These results provide a basis for the lifetime prediction of MPPFCs in pulsed-power applications.

  2. Deposit formation in hydrocarbon rocket fuels

    Science.gov (United States)

    Roback, R.; Szetela, E. J.; Spadaccini, L. J.

    1981-01-01

    An experimental program was conducted to study deposit formation in hydrocarbon fuels under flow conditions that exist in high-pressure, rocket engine cooling systems. A high pressure fuel coking test apparatus was designed and developed and was used to evaluate thermal decomposition (coking) limits and carbon deposition rates in heated copper tubes for two hydrocarbon rocket fuels, RP-1 and commercial-grade propane. Tests were also conducted using JP-7 and chemically-pure propane as being representative of more refined cuts of the baseline fuels. A parametric evaluation of fuel thermal stability was performed at pressures of 136 atm to 340 atm, bulk fuel velocities in the range 6 to 30 m/sec, and tube wall temperatures in the range 422 to 811 K. Results indicated that substantial deposit formation occurs with RP-1 fuel at wall temperatures between 600 and 800 K, with peak deposit formation occurring near 700 K. No improvements were obtained when deoxygenated JP-7 fuel was substituted for RP-1. The carbon deposition rates for the propane fuels were generally higher than those obtained for either of the kerosene fuels at any given wall temperature. There appeared to be little difference between commercial-grade and chemically-pure propane with regard to type and quantity of deposit. Results of tests conducted with RP-1 indicated that the rate of deposit formation increased slightly with pressure over the range 136 atm to 340 atm. Finally, lating the inside wall of the tubes with nickel was found to significantly reduce carbon deposition rates for RP-1 fuel.

  3. Ablative Rocket Deflector Testing and Computational Modeling

    Science.gov (United States)

    Allgood, Daniel C.; Lott, Jeffrey W.; Raines, Nickey

    2010-01-01

    A deflector risk mitigation program was recently conducted at the NASA Stennis Space Center. The primary objective was to develop a database that characterizes the behavior of industry-grade refractory materials subjected to rocket plume impingement conditions commonly experienced on static test stands. The program consisted of short and long duration engine tests where the supersonic exhaust flow from the engine impinged on an ablative panel. Quasi time-dependent erosion depths and patterns generated by the plume impingement were recorded for a variety of different ablative materials. The erosion behavior was found to be highly dependent on the material s composition and corresponding thermal properties. For example, in the case of the HP CAST 93Z ablative material, the erosion rate actually decreased under continued thermal heating conditions due to the formation of a low thermal conductivity "crystallization" layer. The "crystallization" layer produced near the surface of the material provided an effective insulation from the hot rocket exhaust plume. To gain further insight into the complex interaction of the plume with the ablative deflector, computational fluid dynamic modeling was performed in parallel to the ablative panel testing. The results from the current study demonstrated that locally high heating occurred due to shock reflections. These localized regions of shock-induced heat flux resulted in non-uniform erosion of the ablative panels. In turn, it was observed that the non-uniform erosion exacerbated the localized shock heating causing eventual plume separation and reversed flow for long duration tests under certain conditions. Overall, the flow simulations compared very well with the available experimental data obtained during this project.

  4. Standard practice for evaluating performance characteristics of ultrasonic Pulse-Echo testing instruments and systems without the use of electronic measurement instruments

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2011-01-01

    1.1 This practice describes procedures for evaluating the following performance characteristics of ultrasonic pulse-echo examination instruments and systems: Horizontal Limit and Linearity; Vertical Limit and Linearity; Resolution - Entry Surface and Far Surface; Sensitivity and Noise; Accuracy of Calibrated Gain Controls. Evaluation of these characteristics is intended to be used for comparing instruments and systems or, by periodic repetition, for detecting long-term changes in the characteristics of a given instrument or system that may be indicative of impending failure, and which, if beyond certain limits, will require corrective maintenance. Instrument characteristics measured in accordance with this practice are expressed in terms that relate to their potential usefulness for ultrasonic testing. Instrument characteristics expressed in purely electronic terms may be measured as described in E1324. 1.2 Ultrasonic examination systems using pulsed-wave trains and A-scan presentation (rf or video) may be ev...

  5. Hybrid Rocket Experiment Station for Capstone Design

    Science.gov (United States)

    Conley, Edgar; Hull, Bethanne J.

    2012-01-01

    Portable hybrid rocket motors and test stands can be seen in many papers but none have been reported on the design or instrumentation at such a small magnitude. The design of this hybrid rocket and test stand is to be small and portable (suitcase size). This basic apparatus will be used for demonstrations in rocket propulsion. The design had to include all of the needed hardware to operate the hybrid rocket unit (with the exception of the external Oxygen tank). The design of this project includes making the correlation between the rocket's thrust and its size, the appropriate transducers (physical size, resolution, range, and cost), compatability with a laptop analog card, the ease of setup, and its portability.

  6. Integrated approach for hybrid rocket technology development

    Science.gov (United States)

    Barato, Francesco; Bellomo, Nicolas; Pavarin, Daniele

    2016-11-01

    Hybrid rocket motors tend generally to be simple from a mechanical point of view but difficult to optimize because of their complex and still not well understood cross-coupled physics. This paper addresses the previous issue presenting the integrated approach established at University of Padua to develop hybrid rocket based systems. The methodology tightly combines together system analysis and design, numerical modeling from elementary to sophisticated CFD, and experimental testing done with incremental philosophy. As an example of the approach, the paper presents the experience done in the successful development of a hybrid rocket booster designed for rocket assisted take off operations. It is thought that following the proposed approach and selecting carefully the most promising applications it is possible to finally exploit the major advantages of hybrid rocket motors as safety, simplicity, low cost and reliability.

  7. Spectroscopic properties and pulsed laser performance of thulium-doped (Lu,Y)3Al5O12 mixed crystal

    Science.gov (United States)

    Zhao, Yongguang; Zhou, Wei; Xu, Xiaodong; Shen, Deyuan

    2016-12-01

    In this paper, we describe a thulium-doped (Lu,Y)3Al5O12 mixed crystal that was designed and grown to achieve a large pulse energy in Q-switched laser operation. Its absorption cross-sections at 781.3 nm and 1629.2 nm were calculated to be 3.4 × 10-21 cm2 and 5 × 10-21 cm2, respectively, and the emission cross-section at 2018.3 nm was calculated to be 1.92 × 10-21 cm2. The highest single pulse energy of 1.4 mJ near 2.02 μm was realized in an actively Q-switched solid-state laser, and further power scaling was just limited by the damage of the crystal coating. Based on the calculated spectrum parameters, theoretical simulation of the single pulse energy that considering the cross-relaxation process was proposed, which was well consistent with the experimental results.

  8. Design, construction, test and field support of a containerless payload package for rocket flight. [electromagnetic heating and confinement

    Science.gov (United States)

    1977-01-01

    The performance of a device for electromagnetically heating and positioning containerless melts during space processing was evaluated during a 360 second 0-g suborbital sounding rocket flight. Components of the electromagnetic containerless processing package (ECPP), its operation, and interface with the rocket are described along with flight and qualification tests results.

  9. Verification of Model of Calculation of Intra-Chamber Parameters In Hybrid Solid-Propellant Rocket Engines

    Directory of Open Access Journals (Sweden)

    Zhukov Ilya S.

    2016-01-01

    Full Text Available On the basis of obtained analytical estimate of characteristics of hybrid solid-propellant rocket engine verification of earlier developed physical and mathematical model of processes in a hybrid solid-propellant rocket engine for quasi-steady-state flow regime was performed. Comparative analysis of calculated and analytical data indicated satisfactory comparability of simulation results.

  10. Verification of Model of Calculation of Intra-Chamber Parameters In Hybrid Solid-Propellant Rocket Engines

    OpenAIRE

    Zhukov Ilya S.; Borisov Boris V.; Bondarchuk Sergey S.; Zhukov Alexander S.

    2016-01-01

    On the basis of obtained analytical estimate of characteristics of hybrid solid-propellant rocket engine verification of earlier developed physical and mathematical model of processes in a hybrid solid-propellant rocket engine for quasi-steady-state flow regime was performed. Comparative analysis of calculated and analytical data indicated satisfactory comparability of simulation results.

  11. Coordinated control for regulation/protection mode-switching of ducted rockets

    Science.gov (United States)

    Qi, Yiwen; Bao, Wen; Zhao, Jun; Chang, Juntao

    2014-05-01

    This study is concerned with the coordinated control problem for regulation/protection mode-switching of a ducted rocket, in order to obtain the maximum system performance while ensuring safety. The proposed strategy has an inner/outer loop control structure which decomposes the contradiction between performance and safety into two modes of regulation and protection. Specifically, first, the mathematical model including the actuator (gas regulating system) and the plant (ducted rocket engine) is introduced. Second, taking the inlet buzz for instance, the ducted rocket coordinated control problem for thrust regulation and inlet buzz limit protection is formulated and discussed. Third, to solve the problem, based on the main inner loop, a limit protection controller (outer loop) design method is developed utilizing a linear quadratic optimal control technique, and a coordinated control logic is then presented. At last, the whole coordinated control strategy is applied to the ducted rocket control model, and simulation results demonstrate its effectiveness.

  12. Materials Characterization of Additively Manufactured Components for Rocket Propulsion

    Science.gov (United States)

    Carter, Robert; Draper, Susan; Locci, Ivan; Lerch, Bradley; Ellis, David; Senick, Paul; Meyer, Michael; Free, James; Cooper, Ken; Jones, Zachary

    2015-01-01

    To advance Additive Manufacturing (AM) technologies for production of rocket propulsion components the NASA Glenn Research Center (GRC) is applying state of the art characterization techniques to interrogate microstructure and mechanical properties of AM materials and components at various steps in their processing. The materials being investigated for upper stage rocket engines include titanium, copper, and nickel alloys. Additive manufacturing processes include laser powder bed, electron beam powder bed, and electron beam wire fed processes. Various post build thermal treatments, including Hot Isostatic Pressure (HIP), have been studied to understand their influence on microstructure, mechanical properties, and build density. Micro-computed tomography, electron microscopy, and mechanical testing in relevant temperature environments has been performed to develop relationships between build quality, microstructure, and mechanical performance at temperature. A summary of GRC's Additive Manufacturing roles and experimental findings will be presented.

  13. Material Characterization of Additively Manufactured Components for Rocket Propulsion

    Science.gov (United States)

    Carter, Robert; Draper, Susan; Locci, Ivan; Lerch, Bradley; Ellis, David; Senick, Paul; Meyer, Michael; Free, James; Cooper, Ken; Jones, Zachary

    2015-01-01

    To advance Additive Manufacturing (AM) technologies for production of rocket propulsion components the NASA Glenn Research Center (GRC) is applying state of the art characterization techniques to interrogate microstructure and mechanical properties of AM materials and components at various steps in their processing. The materials being investigated for upper stage rocket engines include titanium, copper, and nickel alloys. Additive manufacturing processes include laser powder bed, electron beam powder bed, and electron beam wire fed processes. Various post build thermal treatments, including Hot Isostatic Pressure (HIP), have been studied to understand their influence on microstructure, mechanical properties, and build density. Micro-computed tomography, electron microscopy, and mechanical testing in relevant temperature environments has been performed to develop relationships between build quality, microstructure, and mechanical performance at temperature. A summary of GRCs Additive Manufacturing roles and experimental findings will be presented.

  14. Rocket Experiment For Neutral Upwelling

    Science.gov (United States)

    Kenward, D. R.; Lessard, M.

    2015-12-01

    Observations from the CHAMP satellite from 2004 show relatively small scale heating in the thermosphere. Several different mechanisms have been proposed to explain this phenomenon. The RENU 2 rocket mission includes a suite of 14 instruments which will acquire data to help understand processes involved in neutral upwelling in the cusp. Neutral, ion, and electron measurements will be made to provide an assessment of the upwelling process. SUPERDarn measurements of large- scale Joule heating in the cusp during overflight will also be acquired. Small-scale data which could possibly be associated with Alfvén waves, will be acquired using onboard electric field measurements. In-situ measurement of precipitating electrons and all other measurements will be used in thermodynamic and electrodynamic models for comparison to the observed upwelling.

  15. Heterogeneous fuel for hybrid rocket

    Science.gov (United States)

    Stickler, David B. (Inventor)

    1996-01-01

    Heterogeneous fuel compositions suitable for use in hybrid rocket engines and solid-fuel ramjet engines, The compositions include mixtures of a continuous phase, which forms a solid matrix, and a dispersed phase permanently distributed therein. The dispersed phase or the matrix vaporizes (or melts) and disperses into the gas flow much more rapidly than the other, creating depressions, voids and bumps within and on the surface of the remaining bulk material that continuously roughen its surface, This effect substantially enhances heat transfer from the combusting gas flow to the fuel surface, producing a correspondingly high burning rate, The dispersed phase may include solid particles, entrained liquid droplets, or gas-phase voids having dimensions roughly similar to the displacement scale height of the gas-flow boundary layer generated during combustion.

  16. Flutter Analysis of RX-420 Balistic Rocket Fin Involving Rigid Body Modes of Rocket Structures

    Directory of Open Access Journals (Sweden)

    Novi Andria

    2013-03-01

    Full Text Available Flutter is a phenomenon that has brought a catastrophic failure to the flight vehicle structure. In this experiment, flutter was analyzed for its symmetric and antisymmetric configuration to understand the effect of rocket rigid modes to the fin flutter characteristic. This research was also expected to find out the safety level of RX-420 structure design. The analysis was performed using half rocket model. Fin structure used in this research was a fin which has semispan 600 mm, thickness 12 mm, chord root 700 mm, chord tip 400 mm, made by Al 6061-T651, double spar configuration with skin thickness of 2 mm. Structural dynamics and flutter stability were analyzed using finite element software implemented on MSC. Nastran. The analysis shows that the antisymmetric flutter mode is more critical than symmetric flutter mode. At sea level altitude, antisymmetric flutter occurs at 6.4 Mach, and symmetric flutter occurs at 10.15 Mach. Compared to maximum speed of RX-420 which is 4.5 Mach at altitude 11 km or equivalent to 2.1 Mach at sea level, it can be concluded that the RX-420 structure design is safe, and flutter will not occur during flight.

  17. Rhinoconjunctivitis and occupational asthma caused by Diplotaxis erucoides (wall rocket).

    Science.gov (United States)

    Brito, F F; Mur, P; Bartolomé, B; Galindo, P A; Gómez, E; Borja, J; Martínez, A

    2001-07-01

    Wall rocket (Diplotaxis erucoides) is a common Crucifera plant that grows in European and American vineyards and olive groves. We present the cases of 2 farmers with rhinoconjunctivitis and asthma related to wine-growing tasks during D erucoides pollination (March-April). The aim of this work was to demonstrate that occupational symptoms were caused by D erucoides pollen sensitization. Cutaneous tests, specific IgE measurements, conjunctival and bronchial provocation tests, and peak-flow measurements during working days were performed.

  18. SMC Standard: Evaluation and Test Requirements for Liquid Rocket Engines

    Science.gov (United States)

    2017-07-26

    Company, 2002. 23. NASA SP-8123, Liquid Rocket Lines, Bellows, Flexible Hoses, and Filters, National Aeronautics and Space Administration, April 1977...boundaries established by design requirements. For example, the test screens for malfunctions, failure to execute, sequence of action, interruption...Test: A static load or pressure test performed as an acceptance workmanship screen to prove the structural integrity of a unit or assembly. Gives

  19. PulseSoar

    Energy Technology Data Exchange (ETDEWEB)

    Carter, P.; Peglow, S.

    1992-07-21

    This paper is an introduction to the PulseSoar concept. PulseSoar is a hypervelocity airplane that uses existing airport facilities and current technologies to fly at the very edge of space. It will be shown that PulseSoar can fly between any two points on the globe in less than two hours with fuel efficiency exceeding current state of the art commercial airliners. In addition, it will be shown that PulseSoar avoids environmental issues concerning the ozone layer and sonic booms because of its unique flight profile. All of this can be achieved with current technology. PulseSoar does not require the development of enabling technology. It is a concept which can be demonstrated today. The importance of this idea goes beyond the technical significance`s of PulseSoar in terms of feasibility and performance. PulseSoar could provide a crucial economic advantage to America`s largest export market: commercial aircraft. PulseSoar is a breakthrough concept for addressing the emerging markets of long range and high speed aircraft. Application of PulseSoar to commercial transport could provide the US Aerospace industry a substantial lead in offering high speed/long range aircraft to the world`s airlines. The rapid emergence of a US developed high speed aircraft could also be important to our competitiveness in the Pacific Rim and South American economies. A quick and inexpensive demonstration vehicle is proposed to bang the concept to reality within two years. This discussion will address all the major technical subjects encompassed by PulseSoar and identifies several near-term, and low risk, applications which may be further explored with the initial demonstration vehicle. What is PulseSoar? PulseSoar could enable high speed, high altitude and long range flight without many of the difficulties encountered by traditional hypersonic vehicles.

  20. Mechanical and Thermal Design and Qualification of an Atom Interferometer Sounding Rocket Payload

    Science.gov (United States)

    Grosse, J.; Seidel, S. T.; Krutzik, M.; Wendrich, T.; Stamminger, A.; Scharringhausen, M.; Quantus Consortium

    2015-09-01

    The MAIUS-1 experiment is a pathfinder quantum optics experiment about to fly on a VSB-30 sounding rocket in November 2015. The scientific objective of the mission is to demonstrate the feasibility of creating a Bose-Einstein Condensate and performing atom interferometry aboard a sounding rocket with Rubidium 87atoms. This paper will summarize the thermal and mechanical design of the payload and its (sub)systems. Moreover the qualification procedures and the results of the qualification test will be presented.

  1. Impact of a web based interactive simulation game (PULSE) on nursing students' experience and performance in life support training--a pilot study.

    Science.gov (United States)

    Cook, Neal F; McAloon, Toni; O'Neill, Philip; Beggs, Richard

    2012-08-01

    The delivery of effective life support measures is highly associated with the quality, design and implementation of the education that underpins it. Effectively responding to a critical event is a requirement for all nurses illustrating the need for effective educational approaches from pre-registration training through to enhancing and maintaining life support skills after qualification. This paper reports the findings of utilising a web-based multimedia simulation game PULSE (Platform for Undergraduate Life Support Education). The platform was developed to enhance the student experience of life support education, to motivate on-going learning and engagement and to improve psychomotor skills associated with the provision of Intermediate Life Support (ILS) training. Pre training participants played PULSE and during life support training data was collected from an intervention and a control group of final year undergraduate nursing students (N=34). Quantitative analysis of performance took place and qualitative data was generated from a questionnaire assessing the learning experience. A statistically significant difference was found between the competence the groups displayed in the three skills sets of checking equipment, airway assessment and the safe/effective use of defibrillator at ILS level, and PULSE was positively evaluated as an educational tool when used alongside traditional life support training.

  2. Cycle Trades for Nuclear Thermal Rocket Propulsion Systems

    Science.gov (United States)

    White, C.; Guidos, M.; Greene, W.

    2003-01-01

    Nuclear fission has been used as a reliable source for utility power in the United States for decades. Even in the 1940's, long before the United States had a viable space program, the theoretical benefits of nuclear power as applied to space travel were being explored. These benefits include long-life operation and high performance, particularly in the form of vehicle power density, enabling longer-lasting space missions. The configurations for nuclear rocket systems and chemical rocket systems are similar except that a nuclear rocket utilizes a fission reactor as its heat source. This thermal energy can be utilized directly to heat propellants that are then accelerated through a nozzle to generate thrust or it can be used as part of an electricity generation system. The former approach is Nuclear Thermal Propulsion (NTP) and the latter is Nuclear Electric Propulsion (NEP), which is then used to power thruster technologies such as ion thrusters. This paper will explore a number of indirect-NTP engine cycle configurations using assumed performance constraints and requirements, discuss the advantages and disadvantages of each cycle configuration, and present preliminary performance and size results. This paper is intended to lay the groundwork for future efforts in the development of a practical NTP system or a combined NTP/NEP hybrid system.

  3. Nonlinear Control of a Reusable Rocket Engine for Life Extension

    Science.gov (United States)

    Lorenzo, Carl F.; Holmes, Michael S.; Ray, Asok

    1998-01-01

    This paper presents the conceptual development of a life-extending control system where the objective is to achieve high performance and structural durability of the plant. A life-extending controller is designed for a reusable rocket engine via damage mitigation in both the fuel (H2) and oxidizer (O2) turbines while achieving high performance for transient responses of the combustion chamber pressure and the O2/H2 mixture ratio. The design procedure makes use of a combination of linear and nonlinear controller synthesis techniques and also allows adaptation of the life-extending controller module to augment a conventional performance controller of the rocket engine. The nonlinear aspect of the design is achieved using non-linear parameter optimization of a prescribed control structure. Fatigue damage in fuel and oxidizer turbine blades is primarily caused by stress cycling during start-up, shutdown, and transient operations of a rocket engine. Fatigue damage in the turbine blades is one of the most serious causes for engine failure.

  4. Performance and use of composite-substrate-based bipolar lead/acid batteries for pulsed-power applications

    Science.gov (United States)

    Saakes, Michel; Schellevis, Dion; van Trier, Dieter; Wollersheim, Maurice

    A new type of composite substrate is proposed for constructing fast discharge bipolar lead/acid batteries.This newly developed substrate, used for constructing 4 V bipolar lead/acid batteries, displays no corrosion and a very low catalytic effectfor both hydrogen and oxygen evolution. The specific resistance is 1.2 Ω cm while the areal resistance is 0.04 Ω cm 2. The activelayers are formed by the Planté formation method, both in situ and ex situ. For pulsed-power applications, where energy is quickly transferredto an inductor, a model calculation is given for deriving the required ratio of the specific power and the specific energy.

  5. Centaur Rocket Installation in PSL #1

    Science.gov (United States)

    1962-01-01

    Centaur Rocket Installation in PSL - Propulsion Systems Laboratory #1. The RL-10 Rocket was developed by Pratt and Whitney in the late 1950's and tested at the Lewis Research Center (now known as the John H. Glenn Research Lewis Field). This power plant was the propulsion system for NASA's upper stage Centaur rocket and was significant for being the first to use liquid hydrogen and oxygen as fuel. The Centaur suffered a number of early failures, but later proved to be a very successful upper stage for numerous commercial, NASA and military payloads.

  6. STARLITE figures of merit for tokamak current drive -- Economic analysis of pulsed and steady state power plants with various engineering and physics performance parameters

    Energy Technology Data Exchange (ETDEWEB)

    Ehst, D.A. [Argonne National Lab., IL (United States); Jardin, S.; Kessel, C. [Princeton Univ., NJ (United States). Plasma Physics Lab.

    1995-10-01

    The physics efficiency of current drive ({gamma}{sub B} {proportional_to} n{sub e} I{sub 0} R{sub 0}/P{sub CD}), including the bootstrap effect, needs to exceed certain goals in order to provide economical steady state operation compared to pulsed power plants. The goal for {gamma}{sub B} depends not only on engineering performance of the current drive system, but also on normalized beta and the effective safety factor of the achievable MHD equilibrium.

  7. Starlite figures of merit for tokamak current drive - economic analysis of pulsed and steady state power plants with various engineering and physics performance parameters

    Energy Technology Data Exchange (ETDEWEB)

    Ehst, D.A.

    1995-09-01

    The physics efficiency of current drive ({gamma}{sub B} {proportional_to} n{sub e} I{sub o} R{sub o}/P{sub CD}), including the bootstrap effect, needs to exceed certain goals in order to provide economical steady state operation compared to pulsed power plants. The goal for {gamma}{sub B} depends not only on engineering performance of the current drive system, but also on normalized beta and the effective safety factor of the achievable MHD equilibrium.

  8. Early Spin-Stabilised Rockets - the Rockets of Bergrat Heinrich Gottlob Kuhn

    Science.gov (United States)

    Fricke, H.-D.

    19th century's war rockets were at first stabilised by sticks, but these sticks produced a very uncertain flight path and it often happened that rockets changed their direction and even flew back to their firing position. So very many early inventors in Europe, America, and British-India tried to stabilise the rocket's flight in a better way. They tried fins and even rotation but they did not succeed. It is said in history that William Hale was the first who succeeded in constructing a spin stabilised (i.e. rotating) rocket which worked. But before him, in the thirties of that century, a German amateur rocket inventor succeeded as well and secretly proved his stickless rotating rockets in trials for Prussian officers and some years later officially for Saxon artillery officers. His invention was then bought by the kingdom of Saxony, but these were never use in the field because of lack of money.

  9. Magnetic bearings: A key technology for advanced rocket engines?

    Science.gov (United States)

    Girault, J. PH.

    1992-01-01

    For several years, active magnetic bearings (AMB) have demonstrated their capabilities in many fields, from industrial compressors to control wheel suspension for spacecraft. Despite this broad area, no significant advance has been observed in rocket propulsion turbomachinery, where size, efficiency, and cost are crucial design criteria. To this respect, Societe Europeenne de Propulsion (SEP) had funded for several years significant efforts to delineate the advantages and drawbacks of AMB applied to rocket propulsion systems. Objectives of this work, relative technological basis, and improvements are described and illustrated by advanced turbopump layouts. Profiting from the advantages of compact design in cryogenic environments, the designs show considerable improvements in engine life, performances, and reliability. However, these conclusions should still be tempered by high recurrent costs, mainly due to the space-rated electronics. Development work focused on this point and evolution of electronics show the possibility to decrease production costs by an order of magnitude.

  10. Scaling theory for liquid propellant rocket thrust chambers

    Directory of Open Access Journals (Sweden)

    C. M. Sethna

    1960-04-01

    Full Text Available With the advent of the very large liquid propellant rocket, it has become necessary, if possible, to derive a rational scaling theory for combustion chamber design so as to enable relatively simple and economical initial tests to be carried out on small scaled models using scaled parameters of propellant mass flows, pressure etc., and from these to predict operating and design data for the full scale rocket. Owing to the complex and interdependent nature of the aerothermo-chemical processes in the chamber involving evaporation, diffusion and chemical reaction, the similarity criteria must necessarily extend over several, non-dimensional parameters, but it is still possible to evolve relatively simple rules for correlating the design and performance of the model and large scale motors-as shown by Penner-Tsien and Crocco. The paper concludes with a discussion of the accuracy and practical feasibility of such scaling rules.

  11. Magnesium and Carbon Dioxide - A Rocket Propellant for Mars Missions

    Science.gov (United States)

    Shafirovich, E. IA.; Shiriaev, A. A.; Goldshleger, U. I.

    1993-01-01

    A rocket engine for Mars missions is proposed that could utilize CO2 accumulated from the Martian atmosphere as an oxidizer. For use as possible fuel, various metals, their hydrides, and mixtures with hydrogen compounds are considered. Thermodynamic calculations show that beryllium fuels ensure the most impulse but poor inflammability of Be and high toxicity of its compounds put obstacles to their applications. Analysis of the engine performance for other metals together with the parameters of ignition and combustion show that magnesium seems to be the most promising fuel. Ballistic estimates imply that a hopper with the chemical rocket engine on Mg + CO2 propellant could be readily developed. This vehicle would be able to carry out 2-3 ballistic flights on Mars before the final ascent to orbit.

  12. Developing Avionics Hardware and Software for Rocket Engine Testing

    Science.gov (United States)

    Aberg, Bryce Robert

    2014-01-01

    My summer was spent working as an intern at Kennedy Space Center in the Propulsion Avionics Branch of the NASA Engineering Directorate Avionics Division. The work that I was involved with was part of Rocket University's Project Neo, a small scale liquid rocket engine test bed. I began by learning about the layout of Neo in order to more fully understand what was required of me. I then developed software in LabView to gather and scale data from two flowmeters and integrated that code into the main control software. Next, I developed more LabView code to control an igniter circuit and integrated that into the main software, as well. Throughout the internship, I performed work that mechanics and technicians would do in order to maintain and assemble the engine.

  13. 21 CFR 866.4830 - Rocket immunoelectro-phoresis equipment.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Rocket immunoelectro-phoresis equipment. 866.4830... § 866.4830 Rocket immunoelectro-phoresis equipment. (a) Identification. Rocket immunoelectrophoresis... called rocket immunoelectrophoresis. In this procedure, an electric current causes the protein...

  14. Dual-fuel, dual-mode rocket engine

    Science.gov (United States)

    Martin, James A. (Inventor)

    1989-01-01

    The invention relates to a dual fuel, dual mode rocket engine designed to improve the performance of earth-to-orbit vehicles. For any vehicle that operates from the earth's surface to earth orbit, it is advantageous to use two different fuels during its ascent. A high density impulse fuel, such as kerosene, is most efficient during the first half of the trajectory. A high specific impulse fuel, such as hydrogen, is most efficient during the second half of the trajectory. The invention allows both fuels to be used with a single rocket engine. It does so by adding a minimum number of state-of-the-art components to baseline single made rocket engines, and is therefore relatively easy to develop for near term applications. The novelty of this invention resides in the mixing of fuels before exhaust nozzle cooling. This allows all of the engine fuel to cool the exhaust nozzle, and allows the ratio of fuels used throughout the flight depend solely on performance requirements, not cooling requirements.

  15. Development of Kabila rocket: A radioisotope heated thermionic plasma rocket engine

    OpenAIRE

    2015-01-01

    A new type of plasma rocket engine, the Kabila rocket, using a radioisotope heated thermionic heating chamber instead of a conventional combustion chamber or catalyst bed is introduced and it achieves specific impulses similar to the ones of conventional solid and bipropellant rockets. Curium-244 is chosen as a radioisotope heat source and a thermal reductive layer is also used to obtain precise thermionic emissions. The self-sufficiency principle is applied by simultaneously heating up the e...

  16. Performance and use of composite-substrate-based bipolar lead/acid batteries for pulsed-power applications

    Energy Technology Data Exchange (ETDEWEB)

    Saakes, M.; Schellevis, D.; Trier, D. van [TNO-Environment, Energy and Process Innovation, Delft (Netherlands); Wollersheim, M. [TNO PML-Pulse Physics Lab. Rijswijk (Netherlands)

    1997-07-01

    A new type of composite substrate is proposed for constructing fast discharge bipolar lead/acid batteries. This newly developed substrate, used for constructing 4 V bipolar lead/acid batteries, displays no corrosion and a very low catalytic effect for both hydrogen and oxygen evolution. The specific resistance is 1.2 {Omega} cm while the areal resistance is 0.04 {Omega} cm{sup 2}. The active layers are formed by the Plante formation method, both in situ and ex situ. For pulsed-power applications, where energy is quickly transferred to an inductor, a model calculation is given for driving the required ratio of the specific power and the specific energy. (orig.)

  17. The high performance readout chain for the DSSC 1Megapixel detector, designed for high throughput during pulsed operation mode

    Science.gov (United States)

    Kirchgessner, M.; Soldat, J.; Kugel, A.; Donato, M.; Porro, M.; Fischer, P.

    2015-01-01

    The readout chain of the DSSC 1M pixel detector currently built at DESY, Hamburg for the European X-Ray Free Electron Laser is described. The system operates in pulsed operation mode comparable to the new ILC. Each 0.1 seconds 800 images of 1M pixels are produced and readout by the DSSC DAQ electronics. The total data production rate of the system is about 134 Gbit/s. In order to deal with the high data rates, latest technology components like the Xilinx Kintex 7 FPGA are used to implement fast DDR3-1600 image buffers, high speed serial FPGA to FPGA communication and 10 GB Ethernet links concentrated in one 40 Gbit/s QSFP+ transceiver.

  18. Study on improving performance of airlift device by self-excited oscillation pulsed jet used in mining under water

    Institute of Scientific and Technical Information of China (English)

    YANG Lin; CAI Shu-peng; TANG Chuan-lin

    2008-01-01

    The feasibility of the nozzle of self-excited oscillation pulsed jet (SEOPJ) as the breaker and loosing device for the air-lift pump was researched.The dynamic characteristics of the SEOPJ to crush the hard clay and loose the layer of ore deposit were explored experimentally under the submerged condition.The results show that the SEOPJ not only effectively breaks the hard clay or loose the particles of sand on the placer bed,but also produces fluctuating uplift force acting on particles of sand.The oscillating cross flow caused by the SEOPJ makes particles of sand move to the end of the suction pipe easily.Energy efficency of the airlift and concentration of the solids for the solid-liquid mixture sucked by the air-lift pump are increased obviously with the breaker of SEOPJ.

  19. Facet-dependent photocatalytic performance of NiO oriented thin films prepared by pulsed laser deposition

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yali; Zhang, Feng; Wei, Ling [Key Laboratory of Photovoltaic Materials of Henan Province, School of Physics and Electronics, Henan University, Kaifeng 475004 (China); Institute of Physics for Microsystems, Henan University, Kaifeng 475004 (China); Li, Guoqiang, E-mail: gqli1980@henu.edu.cn [Key Laboratory of Photovoltaic Materials of Henan Province, School of Physics and Electronics, Henan University, Kaifeng 475004 (China); Institute of Physics for Microsystems, Henan University, Kaifeng 475004 (China); Zhang, Weifeng, E-mail: wfzhang@henu.edu.cn [Key Laboratory of Photovoltaic Materials of Henan Province, School of Physics and Electronics, Henan University, Kaifeng 475004 (China)

    2015-01-15

    NiO oriented thin film samples were grown on LaAlO{sub 3} (100), LaAlO{sub 3} (110) and LaAlO{sub 3} (111) substrates by the pulsed laser deposition. The photocatalytic activities of the samples were investigated by degradation of rhodamine B (RhB) under full arc irradiation of a Xe lamp. NiO oriented thin films exhibited difference in photocatalytic oxidization activity. The increasing order of RhB degradation is (100)<(110)<(111), which is consistent with the order of {sup ·}OH generation. The XPS results implied that the ratio of adsorbed oxygen to lattice oxygen was related to the photocatalytic activity.

  20. Study on improving performance of airlift device by self-excited oscillation pulsed jet used in mining under water

    Institute of Scientific and Technical Information of China (English)

    YANG Lin; CAI Shu-peng; TANG Chuan-lin

    2008-01-01

    The feasibility of the nozzle of self-excited oscillation pulsed jet (SEOPJ) as the breaker and loosing device for the air-lift pump was researched. The dynamic characteris-tics of the SEOPJ to crush the hard clay and loose the layer of ore deposit were explored experimentally under the submerged condition. The results show that the SEOPJ not only effectively breaks the hard clay or loose the particles of sand on the placer bed, but also produces fluctuating uplift force acting on particles of sand. The oscillating cross flow caused by the SEOPJ makes particles of sand move to the end of the suction pipe easily. Energy efficency of the airlift and concentration of the solids for the solid-liquid mixture sucked by the air-lift pump are increased obviously with the breaker of SEOPJ.

  1. Performance analysis of linear bandpass filter and pulse inversion in separating subharmonic frequency of signals from ultrasound contrast agent

    Directory of Open Access Journals (Sweden)

    Chinda Samakee

    2012-12-01

    Full Text Available Recently, many publications reported the generation of subharmonic frequency (f0/2 and its potential use in imagingfrom ultrasound contrast agent (UCA. Subharmonic imaging (SHI has provided better contrast resolution over the secondharmonic signals due to the lack of subharmonic generation in the tissue region. However, subharmonic separation in SHIutilizes linear bandpass filtering only. In this paper, we compare the subharmonic separation capability of linear band filter(LBF, pulse inversion (PI, and their combination (PILBF based on contrast-to-tissue ratio (CTR. Results show that theCTR values from the LBF, the PI, and the PILBF are 20.30, 40.30, and 52.74 dB, respectively. The optimal stopband attenuation and fractional bandwidth for the PILBF method are 50 dB and 10%, respectively. This high CTR value indicates thefeasibility of the PILBF method in creating high quality ultrasound image from subharmonic frequency.

  2. High-speed schlieren imaging of rocket exhaust plumes

    Science.gov (United States)

    Coultas-McKenney, Caralyn; Winter, Kyle; Hargather, Michael

    2016-11-01

    Experiments are conducted to examine the exhaust of a variety of rocket engines. The rocket engines are mounted in a schlieren system to allow high-speed imaging of the engine exhaust during startup, steady state, and shutdown. A variety of rocket engines are explored including a research-scale liquid rocket engine, consumer/amateur solid rocket motors, and water bottle rockets. Comparisons of the exhaust characteristics, thrust and cost for this range of rockets is presented. The variety of nozzle designs, target functions, and propellant type provides unique variations in the schlieren imaging.

  3. Performance studies of annular pulse detonation engine ejectors%环形脉冲爆震发动机引射性能

    Institute of Scientific and Technical Information of China (English)

    秦亚欣; 于军力; 高歌

    2011-01-01

    The distributions of detonation parameters in detonation chamber were gained by analytical numeration, and then multiple-cycle numerical simulations were carried out after detonation wave broke up to shock wave. The analysis on the mechanism of unsteady ejection shows that the process of unsteady ejection can be divided to four stages, and the ejection performance of annular pulse detonation duct is stronger than round pulse detonation duct. Different structures and parameters could induce different time-averaged thrust augmentations. The better shape of the ejector inlet, interior surface, ejector length-to-diame-ter ratio and axial placement were obtained through analysis, offering references to augment the performance of pulse detonation engine.%采用解析方法得出爆震波在爆震管内的参数分布,应用数值方法对爆震波衰退为激波后的传播、排除过程进行了多循环模拟.通过对环形爆震管非稳态引射过程的分析,得出非稳态引射过程可以分成四个阶段,环形爆震管比传统的圆形爆震管的引射作用更强.不同结构参数的引射喷管对环形爆震管的引射增推性能不同,经过分析,得到了较佳的引射喷管的入口尺寸,内表面形状、长度/直径比以及轴向位置,为提高脉冲爆震发动机的性能提供参考.

  4. Design of a hybrid rocket / inflatable wing UAV

    Science.gov (United States)

    Sudduth, Cory

    This paper discusses the design challenges and development of a UAV that transitions from a rocket, which allows the aircraft to reach a target altitude rapidly, and then deploys an inflatable wing from an enclosed shell in midflight to allow for loitering and surveillance. The wing deployment and transition is tested in static and dynamic environments, while the performance and stability of both the aircraft mode and rocket mode are examined analytically. An in-depth discussion of key components, including the design, analysis and testing, is also included. Designing an UAV that transitions from a high velocity rocket, to a slow velocity UAV provides many difficult and unique design challenges. For example, the incorporation of deployable wing technology into a full UAV system results in many design constraints. In this particular design inflatable wings are used to generate lift during aircraft mode, and the stabilizing fins for the main wing also acted as the fins for the vehicle during its rocket phase. This required the balancing of the two different vehicle configurations to ensure that the aircraft would be able to fly stably in both modes, and transition between them without catastrophic failure. Significant research, and testing went into the finding the best method of storing the inflatable wing, as well as finding the required inflation rate to minimize unsteady aerodynamic affects. Design work was also invested in the development of an inflation system, as it had to be highly reliable, and yet very light weight for use in this small UAV. This paper discusses how these design challenges were overcome, the development and testing of individual sub-components and how they are incorporated into the overall vehicle. The analysis that went into this UAV, as well as methods used to optimize the design in order to minimize weight and maximize the aircraft performance and loitering time is also discussed.

  5. A Historical Systems Study of Liquid Rocket Engine Throttling Capabilities

    Science.gov (United States)

    Betts, Erin M.; Frederick, Robert A., Jr.

    2010-01-01

    This is a comprehensive systems study to examine and evaluate throttling capabilities of liquid rocket engines. The focus of this study is on engine components, and how the interactions of these components are considered for throttling applications. First, an assessment of space mission requirements is performed to determine what applications require engine throttling. A background on liquid rocket engine throttling is provided, along with the basic equations that are used to predict performance. Three engines are discussed that have successfully demonstrated throttling. Next, the engine system is broken down into components to discuss special considerations that need to be made for engine throttling. This study focuses on liquid rocket engines that have demonstrated operational capability on American space launch vehicles, starting with the Apollo vehicle engines and ending with current technology demonstrations. Both deep throttling and shallow throttling engines are discussed. Boost and sustainer engines have demonstrated throttling from 17% to 100% thrust, while upper stage and lunar lander engines have demonstrated throttling in excess of 10% to 100% thrust. The key difficulty in throttling liquid rocket engines is maintaining an adequate pressure drop across the injector, which is necessary to provide propellant atomization and mixing. For the combustion chamber, cooling can be an issue at low thrust levels. For turbomachinery, the primary considerations are to avoid cavitation, stall, surge, and to consider bearing leakage flows, rotordynamics, and structural dynamics. For valves, it is necessary to design valves and actuators that can achieve accurate flow control at all thrust levels. It is also important to assess the amount of nozzle flow separation that can be tolerated at low thrust levels for ground testing.

  6. Enhanced trapped field performance of bulk high-temperature superconductors using split coil, pulsed field magnetization with an iron yoke

    Science.gov (United States)

    Ainslie, M. D.; Fujishiro, H.; Mochizuki, H.; Takahashi, K.; Shi, Y.-H.; Namburi, D. K.; Zou, J.; Zhou, D.; Dennis, A. R.; Cardwell, D. A.

    2016-07-01

    Investigating and predicting the magnetization of bulk superconducting materials and developing practical magnetizing techniques is crucial to using them as trapped field magnets in engineering applications. The pulsed field magnetization (PFM) technique is considered to be a compact, mobile and relative inexpensive way to magnetize bulk samples, requiring shorter magnetization times (on the order of milliseconds) and a smaller and less complicated magnetization fixture; however, the trapped field produced by PFM is generally much smaller than that of slower zero field cooling or field cooling techniques, particularly at lower operating temperatures. In this paper, the PFM of two, standard Ag-containing Gd-Ba-Cu-O samples is carried out using two types of magnetizing coils: (1) a solenoid coil, and (2) a split coil, both of which make use of an iron yoke to enhance the trapped magnetic field. It is shown that a significantly higher trapped field can be achieved using a split coil with an iron yoke, and in order to explain these how this arrangement works in detail, numerical simulations using a 2D axisymmetric finite element method based on the H -formulation are carried to qualitatively reproduce and analyze the magnetization process from both electromagnetic and thermal points of view. It is observed that after the pulse peak significantly less flux exits the bulk when the iron core is present, resulting in a higher peak trapped field, as well as more overall trapped flux, after the magnetization process is complete. The results have important implications for practical applications of bulk superconductors as such a split coil arrangement with an iron yoke could be incorporated into the design of a portable, high magnetic field source/magnet to enhance the available magnetic field or in an axial gap-type bulk superconducting electric machine, where iron can be incorporated into the stator windings to (1) improve the trapped field from the magnetization process

  7. Hydroxyl Tagging Velocimetry for Rocket Plumes Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A non-intrusive method for measuring velocities in a rocket exhaust is proposed in a joint effort by MetroLaser and Vanderbilt University. Hydroxyl Tagging...

  8. Magnesium Based Rockets for Martian Exploration Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In the proposed Phase II program, we will continue the development of Mg bipropellant rockets for Martian PAV applications. In Phase I, we proved the feasibility of...

  9. Magnesium Based Rockets for Martian Exploration Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to develop Mg rockets for Martian ascent vehicle applications. The propellant can be acquired in-situ from MgO in the Martian regolith (5.1% Mg by mass)...

  10. Advanced Vortex Hybrid Rocket Engine (AVHRE) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Orbital Technologies Corporation (ORBITEC) proposes to develop a unique Advanced Vortex Hybrid Rocket Engine (AVHRE) to achieve a highly-reliable, low-cost and...

  11. Advanced Vortex Hybrid Rocket Engine (AVHRE) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — ORBITEC proposes to develop a unique Advanced Vortex Hybrid Rocket Engine (AVHRE) to achieve a safe, highly-reliable, low-cost and uniquely versatile propulsion...

  12. Nuclear Thermal Rocket Element Environmental Simulator (NTREES)

    Science.gov (United States)

    Schoenfeld, Michael

    2009-01-01

    A detailed description of the Nuclear Thermal Rocket Element Environmental Simulator (NTREES) is presented. The contents include: 1) Design Requirements; 2) NTREES Layout; 3) Data Acquisition and Control System Schematics; 4) NTREES System Schematic; and 5) NTREES Setup.

  13. Hydroxyl Tagging Velocimetry for Rocket Plumes Project

    Data.gov (United States)

    National Aeronautics and Space Administration — To address the need for non-intrusive sensors for rocket plume properties, we propose a laser-based velocity diagnostic that does not require seeding, works in high...

  14. Electrodynamic actuators for rocket engine valves

    Science.gov (United States)

    Fiet, O.; Doshi, D.

    1972-01-01

    Actuators, employed in acoustic loudspeakers, operate liquid rocket engine valves by replacing light paper cones with flexible metal diaphragms. Comparative analysis indicates better response time than solenoid actuators, and improved service life and reliability.

  15. Manufacturing Advanced Channel Wall Rocket Liners Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR will adapt and demonstrate a low cost flexible method of manufacturing channel wall liquid rocket nozzles and combustors, while providing developers a...

  16. Collaborative Sounding Rocket launch in Alaska and Development of Hybrid Rockets

    Science.gov (United States)

    Ono, Tomohisa; Tsutsumi, Akimasa; Ito, Toshiyuki; Kan, Yuji; Tohyama, Fumio; Nakashino, Kyouichi; Hawkins, Joseph

    Tokai University student rocket project (TSRP) was established in 1995 for a purpose of the space science and engineering hands-on education, consisting of two space programs; the one is sounding rocket experiment collaboration with University of Alaska Fairbanks and the other is development and launch of small hybrid rockets. In January of 2000 and March 2002, two collaborative sounding rockets were successfully launched at Poker Flat Research Range in Alaska. In 2001, the first Tokai hybrid rocket was successfully launched at Alaska. After that, 11 hybrid rockets were launched to the level of 180-1,000 m high at Hokkaido and Akita in Japan. Currently, Tokai students design and build all parts of the rockets. In addition, they are running the organization and development of the project under the tight budget control. This program has proven to be very effective in providing students with practical, real-engineering design experience and this program also allows students to participate in all phases of a sounding rocket mission. Also students learn scientific, engineering subjects, public affairs and system management through experiences of cooperative teamwork. In this report, we summarize the TSRP's hybrid rocket program and discuss the effectiveness of the program in terms of educational aspects.

  17. Estimation of Initial Disturbances for Rockets Based on Interactions of Rockets and Directional Tubes

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    In the range of the rockets/launcher system itself, the dynamic equations for rocket and directional tube during semi-constraint period have been constructed by using Newton-Euler method. Considering the interaction of rockets and directional tubes when clearances exist, the method of estimating initial disturbances for the rocket by using vibration data of the directional tube has been given. The estimated results have been compared with the simulation results computed by the dynamic simulating software ADAMS. Results computed by the two methods are basically consistent and the computing errors do not increase with the variation of the clearance. The validity of the proposed method has been proved.

  18. Stability of Rocket Flight during Burning

    Directory of Open Access Journals (Sweden)

    T. N. Srivastava

    1967-10-01

    Full Text Available Stability of the rocket motion during burning is discussed taking into consideration gravity, aerodynamic forces and torques. Conditions for stabilizing the rocket motion are investigated. Analysis for initial and final phases of burning is given separately. Stability regions of the projected motions on two dimensional co-ordinate planes are obtained and thereby stability region of the actual motion is derived. Stability diagrams illustrate statically and dynamically stable and unstable regions.

  19. Rocket Rendezvous at Preassigned Destinations with Optimum

    Directory of Open Access Journals (Sweden)

    T. N. Srivastava

    1982-10-01

    Full Text Available The problem of rendezvous of an interceptor rocket vehicle through optimal exit path with a destination rocket vehicle at a preassigned location on the destination orbit has been investigated for non-coaxial coplanar elliptic launch and destination orbits in an inverse square gravitational field. The case, when launch and destination orbits are coplanar circular, is also discussed. In the end numerical results for rendezvous have been obtained taking Earth and Mars orbits as launch and destination orbits respectively.

  20. The CODEX sounding rocket payload

    Science.gov (United States)

    Zeiger, B.; Shipley, A.; Cash, W.; Rogers, T.; Schultz, T.; McEntaffer, R.; Kaiser, M.

    2011-05-01

    We present the CODEX sounding rocket payload, a soft x-ray (0.1-1.0 keV) spectrometer designed to observe diffuse high-surface brightness astronomical sources. The payload is composed of two modules, each with a 3.25° x 3.25° field of view defined by a stack of wire grids that block light not coming to a 3.0 m focus and admit only nearly-collimated light onto an array of 67 diffraction gratings in an off-plane mount. After a 2.0 m throw, the spectrum is detected by offset large-format gaseous electron multiplier (GEM) detectors. CODEX will target the Vela supernova remnant later this year to measure the temperature and abundances and to determine the contributions of various soft x-ray emission mechanisms to the remnant's energy budget; resulting spectra will have resolution (E/▵E) ranging from 50 to 100 across the band. CODEX is the third-generation of similar payloads from the University of Colorado, with an increased bandpass, higher throughput, and a more robust mechanical structure than its predecessors.

  1. High-Performance Anion-Exchange Chromatography Coupled with Pulsed Electrochemical Detection as a Powerful Tool to Evaluate Carbohydrates of Food Interest: Principles and Applications

    Directory of Open Access Journals (Sweden)

    Claudio Corradini

    2012-01-01

    Full Text Available Specific HPLC approaches are essential for carbohydrate characterization in food products. Carbohydrates are weak acids with pKa values in the range 12–14 and, consequently, at high pH can be transformed into oxyanions, and can be readily separated using highly efficient anion-exchange columns. Electrochemical detection in HPLC has been proven to be a powerful analytical technique for the determination of compounds containing electroactive groups; pulsed amperometric detection of carbohydrates is favourably performed by taking advantage of their electrocatalytic oxidation mechanism at a gold working electrode in a basic media. High-performance Anion Exchange Chromatography (HPAEC at high pH coupled with pulsed electrochemical detection (PED is one of the most useful techniques for carbohydrate determination either for routine monitoring or research application. This technique has been of a great impact on the analysis of oligo- and polysaccharides. The compatibility of electrochemical detection with gradient elution, coupled with the high selectivity of the anion-exchange stationary phases, allows mixtures of simple sugars, oligo- and polysaccharides to be separated with high resolution in a single run. A few reviews have been written on HPAEC-PED of carbohydrates of food interest in the last years. In this paper the recent developments in this field are examined.

  2. Experimental study of the influence of cold heat exchanger geometry on the performance of a co-axial pulse tube cooler

    Science.gov (United States)

    Pang, Xiaomin; Dai, Wei; Wang, Xiaotao; Vanapalli, S.; Luo, Ercang

    2016-09-01

    Improving the performance of the pulse tube cooler is one of the important objectives of the current studies. Besides the phase shifters and regenerators, heat exchangers also play an important role in determining the system efficiency and cooling capacity. A series of experiments on a 10 W @ 77 K class co-axial type pulse tube cooler with different cold heat exchanger geometries are presented in this paper. The cold heat exchangers are made from a copper block with radial slots, cut through using electrical discharge machining. Different slot widths varying from 0.12 mm to 0.4 mm and different slot numbers varying from around 20-60 are investigated, while the length of cold heat exchangers are kept the same. The cold heat exchanger geometry is classified into three groups, namely, constant heat transfer area, constant porosity and constant slot width. The study reveals that a large channel width of 0.4 mm (about ten times the thermal penetration depth of helium gas at 77 K, 100 Hz and 3.5 MPa) shows poor performance, the other results show complicated interaction effects between slot width and slot number. These systematic comparison experiments provide a useful reference for selecting a cold heat exchanger geometry in a practical cooler.

  3. Numerical Study on Performance Parameter of Pulsed Liquid Jet Pump%脉冲液体射流泵性能参数的数值研究

    Institute of Scientific and Technical Information of China (English)

    王玲花; 张川; 宁盼华; 干超

    2011-01-01

    定量分析脉冲液体射流泵时均值基本性能方程中的最优工作参数、动量修正系数、时均惯性力与时均惯性水头的变化规律及其对性能的影响,结果表明脉冲射流可以使流体在喉管出口处得到更充分的混合,并且改善射流泵的最优工作参数和范围.%The optimal operating parameters, momentum correction factor, time-average inertia force and time-average inertia head of pulsed liquid jet pump are quantitatively studied based on the time-average basic performance equation, and the impacts on performance are also analyzed. The calculation shows that the pulsed jet can make the fluid to be more fully mixed in the outlet of throat tube and improve the optimal operating parameters and range of liquid jet pump.

  4. Raman Gas Species Measurements in Hydrocarbon-Fueled Rocket Engine Injector Flows

    Science.gov (United States)

    Wehrmeyer, Joseph; Hartfield, Roy J., Jr.; Trinh, Huu P.; Dobson, Chris C.; Eskridge, Richard H.

    2000-01-01

    Rocket engine propellent injector development at NASA-Marshall includes experimental analysis using optical techniques, such as Raman, fluorescence, or Mie scattering. For the application of spontaneous Raman scattering to hydrocarbon-fueled flows a technique needs to be developed to remove the interfering polycyclic aromatic hydrocarbon fluorescence from the relatively weak Raman signals. A current application of such a technique is to the analysis of the mixing and combustion performance of multijet, impinging-jet candidate fuel injectors for the baseline Mars ascent engine, which will burn methane and liquid oxygen produced in-situ on Mars to reduce the propellent mass transported to Mars for future manned Mars missions. The Raman technique takes advantage of the strongly polarized nature of Raman scattering. It is shown to be discernable from unpolarized fluorescence interference by subtracting one polarized image from another. Both of these polarized images are obtained from a single laser pulse by using a polarization-separating calcite rhomb mounted in the imaging spectrograph. A demonstration in a propane-air flame is presented, as well as a high pressure demonstration in the NASA-Marshall Modular Combustion Test Artice, using the liquid methane-liquid oxygen propellant system

  5. Development of the Hawk/Nike Hawk sounding rocket vehicles

    Science.gov (United States)

    Flowers, B. J.

    1976-01-01

    A new sounding rocket family, the Hawk and Nike-Hawk Vehicles, have been developed, flight tested and added to the NASA Sounding Rocket Vehicle Stable. The Hawk is a single-stage vehicle that will carry 35.6 cm diameter payloads weighing 45.5 kg to 91 kg to altitudes of 78 km to 56 km, respectively. The two-stage Nike-Hawk will carry payloads weighing 68 kg to 136 kg to altitudes of 118 km to 113 km, respectively. Both vehicles utilize the XM22E8 Hawk rocket motor which is available in large numbers as a surplus item from the U.S. Army. The Hawk fin and tail can hardware were designed in-house. The Nike tail can and fin hardware are surplus Nike-Ajax booster hardware. Development objectives were to provide a vehicle family with a larger diameter, larger volume payload capability than the Nike-Apache and Nike-Tomahawk vehicles at comparable cost. Both vehicles performed nominally in flight tests.

  6. The FOXSI sounding rocket: Latest analysis and results

    Science.gov (United States)

    Camilo Buitrago-Casas, Juan; Glesener, Lindsay; Christe, Steven; Krucker, Sam; Ishikawa, Shin-Nosuke; Takahashi, Tadayuki; Ramsey, Brian; Han, Raymond

    2016-05-01

    Hard X-ray (HXR) observations are a linchpin for studying particle acceleration and hot thermal plasma emission in the solar corona. Current and past indirectly imaging instruments lack the sensitivity and dynamic range needed to observe faint HXR signatures, especially in the presences of brighter sources. These limitations are overcome by using HXR direct focusing optics coupled with semiconductor detectors. The Focusing Optics X-ray Solar Imager (FOXSI) sounding rocket experiment is a state of the art solar telescope that develops and applies these capabilities.The FOXSI sounding rocket has successfully flown twice, observing active regions, microflares, and areas of the quiet-Sun. Thanks to its far superior imaging dynamic range, FOXSI performs cleaner hard X-ray imaging spectroscopy than previous instruments that use indirect imaging methods like RHESSI.We present a description of the FOXSI rocket payload, paying attention to the optics and semiconductor detectors calibrations, as well as the upgrades made for the second flight. We also introduce some of the latest FOXSI data analysis, including imaging spectroscopy of microflares and active regions observed during the two flights, and the differential emission measure distribution of the nonflaring corona.

  7. Development of the Hawk/Nike Hawk sounding rocket vehicles

    Science.gov (United States)

    Flowers, B. J.

    1976-01-01

    A new sounding rocket family, the Hawk and Nike-Hawk Vehicles, have been developed, flight tested and added to the NASA Sounding Rocket Vehicle Stable. The Hawk is a single-stage vehicle that will carry 35.6 cm diameter payloads weighing 45.5 kg to 91 kg to altitudes of 78 km to 56 km, respectively. The two-stage Nike-Hawk will carry payloads weighing 68 kg to 136 kg to altitudes of 118 km to 113 km, respectively. Both vehicles utilize the XM22E8 Hawk rocket motor which is available in large numbers as a surplus item from the U.S. Army. The Hawk fin and tail can hardware were designed in-house. The Nike tail can and fin hardware are surplus Nike-Ajax booster hardware. Development objectives were to provide a vehicle family with a larger diameter, larger volume payload capability than the Nike-Apache and Nike-Tomahawk vehicles at comparable cost. Both vehicles performed nominally in flight tests.

  8. Solid Rocket Motor Design Using Hybrid Optimization

    Directory of Open Access Journals (Sweden)

    Kevin Albarado

    2012-01-01

    Full Text Available A particle swarm/pattern search hybrid optimizer was used to drive a solid rocket motor modeling code to an optimal solution. The solid motor code models tapered motor geometries using analytical burn back methods by slicing the grain into thin sections along the axial direction. Grains with circular perforated stars, wagon wheels, and dog bones can be considered and multiple tapered sections can be constructed. The hybrid approach to optimization is capable of exploring large areas of the solution space through particle swarming, but is also able to climb “hills” of optimality through gradient based pattern searching. A preliminary method for designing tapered internal geometry as well as tapered outer mold-line geometry is presented. A total of four optimization cases were performed. The first two case studies examines designing motors to match a given regressive-progressive-regressive burn profile. The third case study studies designing a neutrally burning right circular perforated grain (utilizing inner and external geometry tapering. The final case study studies designing a linearly regressive burning profile for right circular perforated (tapered grains.

  9. Nuclear thermal rockets using indigenous extraterrestrial propellants

    Science.gov (United States)

    Zubrin, Robert M.

    1990-01-01

    A preliminary examination of a concept for a Mars and outer solar system exploratory vehicle is presented. Propulsion is provided by utilizing a nuclear thermal reactor to heat a propellant volatile indigenous to the destination world to form a high thrust rocket exhaust. Candidate propellants, whose performance, materials compatibility, and ease of acquisition are examined and include carbon dioxide, water, methane, nitrogen, carbon monoxide, and argon. Ballistics and winged supersonic configurations are discussed. It is shown that the use of this method of propulsion potentially offers high payoff to a manned Mars mission. This is accomplished by sharply reducing the initial mission mass required in low earth orbit, and by providing Mars explorers with greatly enhanced mobility in traveling about the planet through the use of a vehicle that can refuel itself each time it lands. Thus, the nuclear landing craft is utilized in combination with a hydrogen-fueled nuclear-thermal interplanetary launch. By utilizing such a system in the outer solar system, a low level aerial reconnaissance of Titan combined with a multiple sample return from nearly every satellite of Saturn can be accomplished in a single launch of a Titan 4 or the Space Transportation System (STS). Similarly a multiple sample return from Callisto, Ganymede, and Europa can also be accomplished in one launch of a Titan 4 or the STS.

  10. Transient heat transfer properties in a pulse detonation combustor

    OpenAIRE

    Fontenot, Dion G.

    2011-01-01

    Approved for public release; distribution is unlimited. The heat transfer along the axis of a pulse detonation combustor has been characterized for various frequencies and fill fractions at 2.5 atmospheres of pressure for chamber refresh conditions. In a pulse detonation combustor, a supersonic detonation wave is the method for transforming chemical energy into mechanical energy and the wave propagates much faster than the subsonic flames in devices such as rockets and ramjets. The flow...

  11. Effect of Pulse Detonation-plasma Technology Treatment on Structure of Surface Layer and Performance of T8 Steel

    Directory of Open Access Journals (Sweden)

    ZHANG Lin-wei

    2017-05-01

    Full Text Available T8 steel was carried out surface modification treatment by pulse detonation-plasma(PDP technology with the capacity of 600, 800, 1000μF respectively. The microstructure and phase structure of T8 steel before and after PDP treatment were analyzed by using XRD and SEM. The microhardness and wear resistance before and after treatment were investigated by microhardness tester and wear tester. The results show that the surface smoothing occur first, and then the craters are formed. The craters are caused by the inhomogeneity of PDT energy and the material itself. PDP treatment makes the surface layer of T8 steel changed from martensite α'-Fe to austenite γ-Fe, and the Fe3N is formed due to nitriding phenomenon. The thickness of modified layer is increased with the increasing of the capacity. When the capacity is 1000μF,the average thickness of modified layer is 68.27μm and it composes of columnar and fine grain structure. The thickness of columnar structure is decreased with the decreasing of the capacity. The microhardness is improved by a factor of about 2, and the wear resistance is also obviously increased. The maximum wear resistance is 2.6 times of the matrix.

  12. Infrared signature modelling of a rocket jet plume - comparison with flight measurements

    Science.gov (United States)

    Rialland, V.; Guy, A.; Gueyffier, D.; Perez, P.; Roblin, A.; Smithson, T.

    2016-01-01

    The infrared signature modelling of rocket plumes is a challenging problem involving rocket geometry, propellant composition, combustion modelling, trajectory calculations, fluid mechanics, atmosphere modelling, calculation of gas and particles radiative properties and of radiative transfer through the atmosphere. This paper presents ONERA simulation tools chained together to achieve infrared signature prediction, and the comparison of the estimated and measured signatures of an in-flight rocket plume. We consider the case of a solid rocket motor with aluminized propellant, the Black Brant sounding rocket. The calculation case reproduces the conditions of an experimental rocket launch, performed at White Sands in 1997, for which we obtained high quality infrared signature data sets from DRDC Valcartier. The jet plume is calculated using an in-house CFD software called CEDRE. The plume infrared signature is then computed on the spectral interval 1900-5000 cm-1 with a step of 5 cm-1. The models and their hypotheses are presented and discussed. Then the resulting plume properties, radiance and spectra are detailed. Finally, the estimated infrared signature is compared with the spectral imaging measurements. The discrepancies are analyzed and discussed.

  13. Rockets and People. Volume 1

    Science.gov (United States)

    Chertok, Boris E; Siddiqi, Asif A. (Editor)

    2005-01-01

    Much has been written in the West on the history of the Soviet space program but few Westerners have read direct first-hand accounts of the men and women who were behind the many Russian accomplishments in exploring space.The memoirs of Academician Boris Chertok, translated from the original Russian, fills that gap.Chertok began his career as an electrician in 1930 at an aviation factory near Moscow.Twenty-seven years later, he became deputy to the founding figure of the Soviet space program, the mysterious Chief Designer Sergey Korolev. Chertok s sixty-year-long career and the many successes and failures of the Soviet space program constitute the core of his memoirs, Rockets and People. These writings are spread over four volumes. This is volume I. Academician Chertok not only describes and remembers, but also elicits and extracts profound insights from an epic story about a society s quest to explore the cosmos. In Volume 1, Chertok describes his early years as an engineer and ends with the mission to Germany after the end of World War II when the Soviets captured Nazi missile technology and expertise. Volume 2 takes up the story with the development of the world s first intercontinental ballistic missile ICBM) and ends with the launch of Sputnik and the early Moon probes. In Volume 3, Chertok recollects the great successes of the Soviet space program in the 1960s including the launch of the world s first space voyager Yuriy Gagarin as well as many events connected with the Cold War. Finally, in Volume 4, Chertok meditates at length on the massive Soviet lunar project designed to beat the Americans to the Moon in the 1960s, ending with his remembrances of the Energiya-Buran project.

  14. Investigation of synchronous effects of multi-mesh regenerator and double-inlet on performance of a Stirling pulse tube cryocooler

    Science.gov (United States)

    Arablu, M.; Jafarian, A.

    2013-02-01

    In this paper synchronous effects of multi-mesh regenerator and double-inlet on performance of a Stirling pulse tube cryocooler (SPTC) have been considered. In this respect, a finite volume code was developed to simulate the SPTC. Set of governing equations were written in a general form such that all porous and non-porous sections of the system could be modeled. Results showed that synchronous application of double inlet and multi-mesh regenerator optimizes the phase shift between velocity and pressure at the warm end of the pulse tube, increases the regenerator's outlet pressure amplitude, decreases inertial and viscous losses in the hot end of the regenerator and consequently increases the COP of the system. Furthermore, it was observed that a minimum temperature of 60.3 K and COP of 0.03996 @ 80 K is attainable using optimum multi-mesh regenerator and double inlet; whereas, for a simple SPTC with a uniform mesh regenerator, a minimum temperature of 71.3 K and maximum COP of 0.0227 @ 80 K are concluded.

  15. Pulse-Reverse Electrodeposition and Micromachining of Graphene-Nickel Composite: An Efficient Strategy toward High-Performance Microsystem Application.

    Science.gov (United States)

    Li, Jinhua; An, Zhonglie; Wang, Zhuqing; Toda, Masaya; Ono, Takahito

    2016-02-17

    Graphene reinforced nickel (Ni) is an intriguing nanocomposite with tremendous potential for microelectromechanical system (MEMS) applications by remedying mechanical drawbacks of the metal matrix for device optimization, though very few related works have been reported. In this paper, we developed a pulse-reverse electrodeposition method for synthesizing graphene-Ni (G-Ni) composite microcomponents with high content and homogeneously dispersed graphene filler. While the Vickers hardness is largely enhanced by 2.7-fold after adding graphene, the Young's modulus of composite under dynamic condition shows ∼1.4-fold increase based on the raised resonant frequency of a composite microcantilever array. For the first time, we also demonstrate the application of G-Ni composite in microsystems by fabricating a Si micromirror with the composite supporting beams as well as investigate the long-term stability of the mirror at resonant vibration. Compared with the pure Ni counterpart, the composite mirror shows an apparently lessened fluctuations of resonant frequency and scanning angle due to a suppressed plastic deformation even under the sustaining periodic loading. This can be ascribed to the reduced grain size of Ni matrix and dislocation hindering in the presence of graphene by taking into account the crystalline refinement strengthen mechanism. The rational discussions also imply that the strong interface and efficient load transfer between graphene layers and metal matrix play an important role for improving stiffness in composite. It is believed that a proper design of graphene-metal composite makes it a promising structural material candidate for advanced micromechanical devices.

  16. Determination of neomycin sulfate and impurities using high-performance anion-exchange chromatography with integrated pulsed amperometric detection.

    Science.gov (United States)

    Hanko, Valoran P; Rohrer, Jeffrey S

    2007-01-01

    Neomycin B is one of a class of aminoglycoside antibiotics that lack a good chromophore, and is therefore difficult to determine using reversed-phase HPLC with absorbance detection. This is especially true for determining the quantity of each impurity. We show that neomycin sulfate and its major impurities, including neamine (neomycin A), can be separated on a strong anion-exchange column using a weak potassium hydroxide eluent (2.40 mM) at a column temperature of 30 degrees C, and directly detected by integrated pulsed amperometric detection (IPAD). The resolution (United States Pharmacopeia (USP) definition) between neomycin B and the closest major impurity ranged from 6.56 and 7.45 over 10 days of consecutive analysis (7.24+/-0.10, n=836 injections). Due to the difficulty of producing weak hydroxide eluents of the required purity (i.e. carbonate-free), this method depends on automatic eluent generation to ensure method ruggedness. This method exhibited good long-term (10 days, 822 injections) retention time stability with a R.S.D. of 0.6%. Peak area R.S.D. (10 microM) was 1.3%. Method robustness was evaluated by intentionally varying the flow rate, eluent concentration, column temperature, and column. The spike recoveries of neomycin B from extractions of three different topical ointments and cream formulations ranged from 95 to 100%. The measured concentration of neomycin B in these formulations ranged from 119 to 154% of the label concentration. The R.S.D. for the measured concentration of one of the formulations tested over three separate days, n=11 extracts, was 3.2%. Based on the results of these evaluations, we believe this method can be used for neomycin sulfate identity, assay, and purity.

  17. Effect of hafnium carbide content on the ablative performance of carbon/carbon composites as rocket throats%碳化铪含量对C/C复合材料喉衬烧蚀性能的影响

    Institute of Scientific and Technical Information of China (English)

    李淑萍; 李克智; 杜红英; 张守阳; 沈学涛

    2012-01-01

    Hafnium carbide (HfC) modified carbon/carbon (HfC-C/C) composites were prepared by impregnating carbon felts with a saturated HfOCl2·8H2O ethanol solution and heat treating at 600 ℃ to form HfO2/C composites that were then densified with pyrocarbon by chemical vapor infiltration and graphitized at 2 100 ℃ to convert HfO2 into HfC. The HfC-C/C composites as rocket throats were ablated at 7 MPa and around 3 200 ℃ for 3 s by an experimental solid rocket motor. Results showed that the HfC-C/C composites with HfC contents more than 5.7 mass% had a stable period with a constant ablation rate and the duration of this period increased with HfC content. The overall ablation rate was decreased by 25. 2 and 49. 6% for the composites having 5. 7 and 8.7 mass% HfC respectively as compared with the composite with 2. 5 mass% HfC.%将炭毡浸渍于饱和的HfOCI2·8 H2O乙醇溶液中,经600℃热处理形成HfO2/C复合材料,然后采用热梯度化学气相沉积工艺在2100℃进行致密化和石墨化处理使HfO2转化为HfC而得到碳化铪(HfC)改性、整体炭毡增强的炭/炭(HfC-C/C)复合材料整体喉衬.利用小型固体火箭发动机试车台装置,在7MPa、3200℃烧蚀3s以测定HfC含量对喉衬烧蚀性能的影响.结果表明,HfC质量分数为5.7%的HfC-C/C喉衬线烧蚀率减小了25.2%;HfC质量分数为8.7%的HfC-C/C喉衬线烧蚀率减小了49.6%.同时,当HfC质量分数为5.7%时,HfC-C/C喉衬出现了以恒定线烧蚀率为特征的稳态烧蚀阶段,且该阶段的持续时间随HfC含量的增加而增加.

  18. Desempenho da cultura da rúcula cultivada em época de verão em túneis baixos de polietileno perfurado Performance of rocket press culture in low tunnels with polyethylene plastic perforated in summer

    Directory of Open Access Journals (Sweden)

    Edilaine R. Pereira

    2004-08-01

    Full Text Available O túnel baixo é um tipo de ambiente protegido utilizado, principalmente, em cultivo de espécies de pequeno porte, como alface, morango, pimentão, rúcula e pepino. Por serem estruturas de menor porte, apresentam menor custo de instalação em relação ao túnel alto. A presença de material plástico em sua cobertura proporciona um ganho térmico durante o dia, facilitando o crescimento das plantas, protegendo as culturas do impacto da chuva, dos ventos frios e das temperaturas mínimas. Esta pesquisa teve o objetivo de avaliar o efeito de filme de polietileno com diferentes intensidades de perfurações (0; 5; 10; 15 e 20%, no microclima em túneis baixos e no desenvolvimento da cultura da rúcula (Eruca vesicaria sativa (Mill Thell em época de verão. Os resultados mostraram que houve diferença de produtividade entre os túneis com diferentes níveis de perfuração e houve diferenças significativas quanto às características físicas da planta em alguns tratamentos comparativos à testemunha. Quanto aos aspectos relacionados com o microclima, verificou-se, por meio de análise estatística, que a temperatura do ar observada nos horários mais críticos do dia (11 às 15 h apresentou diferenças significativas entre o ambiente coberto com túnel sem perfuração e o solo descoberto; com relação à umidade absoluta do ar, quanto maior o nível de perfuração do plástico de cobertura do túnel, menor a umidade absoluta observada.Low tunnels is a type of greenhouse that is used for cultivation of species of small load, as lettuce, strawberry, sweet pepper, rocket press and cucumber. This type of greenhouse has a smaller cost of installation than other because its lower high. The plastic covering allows the gain of temperature during the day improving plant growth, protecting the crop from the impact of the rain, cold wind and low temperature. The purpose of this research was to decide the atmosphere changes with the use of

  19. Analytical Method for Sugar Profile in Pet Food and Animal Feeds by High-Performance Anion-Exchange Chromatography with Pulsed Amperometric Detection.

    Science.gov (United States)

    Ellingson, David J; Anderson, Phillip; Berg, Daniel P

    2016-01-01

    There is a need for a standardized, accurate, rugged, and consistent method to measure for sugars in pet foods and animal feeds. Many traditional standard sugar methods exist for other matrixes, but when applied in collaborative studies there was poor agreement and sources of error identified with those standard methods. The advancement in technology over the years has given us the ability to improve on these standard methods of analysis. A method is described here that addresses these common issues and was subjected to a single-laboratory validation to assess performance on a wide variety of pet foods and animal feeds. Of key importance to the method performance is the sample preparation before extraction, type of extraction solvent, postextraction cleanup, and, finally, optimized chromatography using high-performance anion exchange chromatography with pulsed amperometric detection. The results obtained from the validation demonstrate how typical issues seen with these matrixes can influence performance of sugar analysis. The results also demonstrate that this method is fit-for-purpose and can meet the challenges of sugar analysis in pet food and animal feeds to lay the foundation for a standardized method of analysis.

  20. Liquid rocket combustion instability analysis by CFD methods

    Science.gov (United States)

    Grenda, J. M.; Venkateswaran, S.; Merkle, C. L.

    1991-01-01

    Combustion instability in liquid rocket engines is simulated computationally by using a simple two-parameter model for the combustion response function. The objectives of the study are to assess the capabilities of CFD algorithms for instability studies and to investigate the response to parametric effects such as bombs and distributed combustion. Results indicate that numerical solutions of high accuracy can be obtained if a sufficient number of grid points are used per wavelength of the disturbance. The short-term response to bombs or pulses triggers a large number of modes in the combustor whose faithful resolution requires highly dense grids, although there is evidence that correct long-term solutions can be obtained even if all the short-term frequencies are not resolved. Long-term responses to pulses are shown to decay to the most unstable mode in small amplitude cases, and to exhibit limit cycles in large amplitude cases. Comparison of distributed with concentrated heat release indicates the former is more stable for given values of the combustion response parameters, and that the distributed heat release gives rise to higher frequency disturbances. Wave steepening is observed in the solutions, but its effect is less pronounced in multidimensional waves than in one-dimensional waves.

  1. Pulse Voltammetry.

    Science.gov (United States)

    Osteryoung, Janet

    1983-01-01

    Discusses the nature of pulse voltammetry, indicating that its widespread use arises from good sensitivity and detection limits and from ease of application and low cost. Provides analytical and mechanistic applications of the procedure. (JN)

  2. Metallic Hydrogen: A Game Changing Rocket Propellant

    Science.gov (United States)

    Silvera, Isaac F.

    2016-01-01

    The objective of this research is to produce metallic hydrogen in the laboratory using an innovative approach, and to study its metastability properties. Current theoretical and experimental considerations expect that extremely high pressures of order 4-6 megabar are required to transform molecular hydrogen to the metallic phase. When metallic hydrogen is produced in the laboratory it will be extremely important to determine if it is metastable at modest temperatures, i.e. remains metallic when the pressure is released. Then it could be used as the most powerful chemical rocket fuel that exists and revolutionize rocketry, allowing single-stage rockets to enter orbit and chemically fueled rockets to explore our solar system.

  3. Laser-fusion rocket for interplanetary propulsion

    Energy Technology Data Exchange (ETDEWEB)

    Hyde, R.A.

    1983-09-27

    A rocket powered by fusion microexplosions is well suited for quick interplanetary travel. Fusion pellets are sequentially injected into a magnetic thrust chamber. There, focused energy from a fusion Driver is used to implode and ignite them. Upon exploding, the plasma debris expands into the surrounding magnetic field and is redirected by it, producing thrust. This paper discusses the desired features and operation of the fusion pellet, its Driver, and magnetic thrust chamber. A rocket design is presented which uses slightly tritium-enriched deuterium as the fusion fuel, a high temperature KrF laser as the Driver, and a thrust chamber consisting of a single superconducting current loop protected from the pellet by a radiation shield. This rocket can be operated with a power-to-mass ratio of 110 W gm/sup -1/, which permits missions ranging from occasional 9 day VIP service to Mars, to routine 1 year, 1500 ton, Plutonian cargo runs.

  4. The Norwegian Sounding Rocket and Balloon Program

    Science.gov (United States)

    Skatteboe, Rolf

    2001-08-01

    The status and recent developments of the Norwegian Sounding Rocket and Balloon Program are presented with focus on national activities and recent achievements. The main part of the Norwegian program is sounding rocket launches conducted by Andøya Rocket Range from the launch facilities on Andøya and at Svalbard. For the majority of the programs, the scientific goal is investigation of processes in the middle and upper atmosphere. The in situ measurements are supplemented by a large number of ground-based support instruments located at the ALOMAR Observatory. The ongoing and planned projects are described and the highlights of the latest completed projects are given. The scientific program for the period 2001-2003 will be reviewed. Several new programs have been started to improve the services available to the international science comunity. The Hotel Payload project and MiniDusty are important examples that will be introduced in the paper. Available space related infrastructure is summarized.

  5. Atmospheric scavenging of solid rocket exhaust effluents

    Science.gov (United States)

    Fenton, D. L.; Purcell, R. Y.

    1978-01-01

    Solid propellant rocket exhaust was directly utilized to ascertain raindrop scavenging rates for hydrogen chloride. Two chambers were used to conduct the experiments; a large, rigid walled, spherical chamber stored the exhaust constituents, while the smaller chamber housing all the experiments was charged as required with rocket exhaust HCl. Surface uptake experiments demonstrated an HCl concentration dependence for distilled water. Sea water and brackish water HCl uptake was below the detection limit of the chlorine-ion analysis technique used. Plant life HCl uptake experiments were limited to corn and soybeans. Plant age effectively correlated the HCl uptake data. Metallic corrosion was not significant for single 20 minute exposures to the exhaust HCl under varying relative humidity. Characterization of the aluminum oxide particles substantiated the similarity between the constituents of the small scale rocket and the full size vehicles.

  6. Performance Analysis of an Alternative to Trellis Coded Modulation for Waveforms Transmitted over a Channel with Pulse-Noise Interference

    Science.gov (United States)

    2008-06-01

    signal in one set has its antipodal signal in the other. One advantage of biorthogonal modulation over orthogonal modulation for the same data rate... antipodal signal vectors have better distance properties than orthogonal ones, biorthogonal modulation performs slightly better than orthogonal

  7. Effect of Pulsed 5.62 GHz Microwaves on Squirrel Monkeys (Saimiri sciureus) Performing a Repeated Acquisition Task.

    Science.gov (United States)

    1983-01-28

    the behavioral test sessions. Irradiation occurred for 2 minutes or until convulsions began. He found no effect on performance of a discrimination...only a slight, almost imperceptible , decrease during irradiation at power ý-ensities of 17 and 32 mW/cm2 . However, at 38 mW/cm2 this animal respo-ided

  8. Performance of Coherent and Noncoherent RAKE Receivers With Convolutional Coding Ricean Fading and Pulse-Noise Interference

    Science.gov (United States)

    2004-06-01

    Transactions on Information Theory, vol. 48, no.3, pp. 669-682, March 2002. 3. Ziemer, Rodger E., Vojcic, Branimir R., Milstein, Laurence B., and...Multipath Fading Channels,” Proceedings MILCOM, vol. 3, pp.1014-1019, October 1990. 12. Vojcic, Branimir , and Pickholtz, Raymond L., “Performance of

  9. Monomethylhydrazine versus hydrazine fuels - Test results using a 100 pound thrust bipropellant rocket engine

    Science.gov (United States)

    Smith, J. A.; Stechman, R. C.

    1981-01-01

    A test program was performed to evaluate hydrazine (N2H4) as a fuel for a 445 Newton (100 lbf) thrust bipropellant rocket engine. Results of testing with an identical thruster utilizing monomethylhydrazine (MMH) are included for comparison. Engine performance with hydrazine fuel was essentially identical to that experienced with monomethylhydrazine although higher combustor wall temperatures (approximately 400 F) were obtained with hydrazine. Results are presented which indicate that hydrazine as a fuel is compatible with Marquardt bipropellant rocket engines which use monomethylhydrazine as a baseline fuel.

  10. Mathematical Modelling of In-Chamber Processes in Hydrocombined Propellant Solid Rocket Motors

    Directory of Open Access Journals (Sweden)

    Nikolai A. Obukhov

    1998-10-01

    Full Text Available The special conditions of employment of commercial rockets in the sea environment has opened up new possibilities of improving motor performance. The interesting method suggests supplying water into the running motor. This paper reports the calculations and experiments carried out with solid propellant model setups. The results prove the validity of the proposed method and allow the refinement of calculation techniques for the prediction of solid rocket motor performance characteristics. The serviceability of the solid propellant charges working in combination with water is demonstrated. A mathematical model is proposed for the operation of a hydrocombined propellant motor with water and powdered additives applied to the combustion chamber."

  11. Advanced Computer Science on Internal Ballistics of Solid Rocket Motors

    Science.gov (United States)

    Shimada, Toru; Kato, Kazushige; Sekino, Nobuhiro; Tsuboi, Nobuyuki; Seike, Yoshio; Fukunaga, Mihoko; Daimon, Yu; Hasegawa, Hiroshi; Asakawa, Hiroya

    In this paper, described is the development of a numerical simulation system, what we call “Advanced Computer Science on SRM Internal Ballistics (ACSSIB)”, for the purpose of improvement of performance and reliability of solid rocket motors (SRM). The ACSSIB system is consisting of a casting simulation code of solid propellant slurry, correlation database of local burning-rate of cured propellant in terms of local slurry flow characteristics, and a numerical code for the internal ballistics of SRM, as well as relevant hardware. This paper describes mainly the objectives, the contents of this R&D, and the output of the fiscal year of 2008.

  12. Near-term lunar nuclear thermal rocket engine options

    Science.gov (United States)

    Pelaccio, Dennis G.; Scheil, Christine M.; Collins, John T.

    1991-01-01

    The Nuclear Thermal Rocket (NTR) is an attractive candidate propulsion system option for manned planetary missions. Its high performance capability for such missions translates into a substantial reduction in low-earth-orbit (LEO) required mass and trip times with increased operational flexibility. This study examined NTR engine options that could support near-term lunar mission operations. Expander and gas generator cycle, solid-core NERVA derivative reactor-based NTR engines were investigated. Weight, size, operational characteristics, and design features for representative NTR engine concepts are presented. The impact of using these NTR engines for a typical lunar mission scenario is also examined.

  13. Nuclear thermal rocket workshop reference system Rover/NERVA

    Science.gov (United States)

    Borowski, Stanley K.

    1991-01-01

    The Rover/NERVA engine system is to be used as a reference, against which each of the other concepts presented in the workshop will be compared. The following topics are reviewed: the operational characteristics of the nuclear thermal rocket (NTR); the accomplishments of the Rover/NERVA programs; and performance characteristics of the NERVA-type systems for both Mars and lunar mission applications. Also, the issues of ground testing, NTR safety, NASA's nuclear propulsion project plans, and NTR development cost estimates are briefly discussed.

  14. On the hydrodynamics of rocket propellant engine inducers and turbopumps

    Science.gov (United States)

    d'Agostino, L.

    2013-12-01

    The lecture presents an overview of some recent results of the work carried out at Alta on the hydrodynamic design and rotordynamic fluid forces of cavitating turbopumps for liquid propellant feed systems of modern rocket engines. The reduced order models recently developed for preliminary geometric definition and noncavitating performance prediction of tapered-hub axial inducers and centrifugal turbopumps are illustrated. The experimental characterization of the rotordynamic forces acting on a whirling four-bladed, tapered-hub, variable-pitch high-head inducer, under different load and cavitation conditions is presented. Future perspectives of the work to be carried out at Alta in this area of research are briefly illustrated.

  15. Facile synthesis of silicon carbide-titanium dioxide semiconducting nanocomposite using pulsed laser ablation technique and its performance in photovoltaic dye sensitized solar cell and photocatalytic water purification

    Science.gov (United States)

    Gondal, M. A.; Ilyas, A. M.; Baig, Umair

    2016-08-01

    Separation of photo-generated charge carriers (electron and holes) is a major approach to improve the photovoltaic and photocatalytic performance of metal oxide semiconductors. For harsh environment like high temperature applications, ceramic like silicon carbide is very prominent. In this work, 10%, 20% and 40% by weight of pre-oxidized silicon carbide was coupled with titanium dioxide (TiO2) to form nanocomposite semiconductor via elegant pulsed laser ablation in liquid technique using second harmonic 532 nm wavelength of neodymium-doped yttrium aluminium garnet (Nd-YAG) laser. In addition, the effect of silicon carbide concentration on the performance of silicon carbide-titanium dioxide nanocomposite as photo-anode in dye sensitized solar cell and as photocatalyst in photodegradation of methyl orange dye in water was also studied. The result obtained shows that photo-conversion efficiency of the dye sensitized solar cell was improved from 0.6% to 1.65% and the percentage of methyl orange dye removed was enhanced from 22% to 77% at 24 min under ultraviolet-visible solar spectrum in the nanocomposite with 10% weight of silicon carbide. This remarkable performance enhancement could be due to the improvement in electron transfer phenomenon by the presence of silicon carbide on titanium dioxide.

  16. Liquid rocket combustion chamber acoustic characterization

    Directory of Open Access Journals (Sweden)

    Cândido Magno de Souza

    2010-09-01

    Full Text Available Over the last 40 years, many solid and liquid rocket motors have experienced combustion instabilities. Among other causes, there is the interaction of acoustic modes with the combustion and/or fluid dynamic processes inside the combustion chamber. Studies have been showing that, even if less than 1% of the available energy is diverted to an acoustic mode, combustion instability can be generated. On one hand, this instability can lead to ballistic pressure changes, couple with other propulsion systems such as guidance or thrust vector control, and in the worst case, cause motor structural failure. In this case, measures, applying acoustic techniques, must be taken to correct/minimize these influences on the combustion. The combustion chamber acoustic behavior in operating conditions can be estimated by considering its behavior in room conditions. In this way, acoustic tests can be easily performed, thus identifying the cavity modes. This paper describes the procedures to characterize the acoustic behavior in the inner cavity of four different configurations of a combustion chamber. Simple analytical models are used to calculate the acoustic resonance frequencies and these results are compared with acoustic natural frequencies measured at room conditions. Some comments about the measurement procedures are done, as well as the next steps for the continuity of this research. The analytical and experimental procedures results showed good agreement. However, limitations on high frequency band as well as in the identification of specific kinds of modes indicate that numerical methods able to model the real cavity geometry and an acoustic experimental modal analysis may be necessary for a more complete analysis. Future works shall also consider the presence of passive acoustic devices such as baffles and resonators capable of introducing damping and avoiding or limiting acoustic instabilities.

  17. Cusp Alfven and Plasma Electrodynamics Rocket (CAPER) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Launch a single rocket from Andoya Rocket Range into an active cusp event. Observe electric and magnetic fields, HF waves, electron and ion distributions and...

  18. A study of early korean rockets (1377-1600)

    Science.gov (United States)

    Chae, Yeon Seok

    The first Korean rocket was fired between 1377 and 1389 and began the Korean development of rockets as a tactical weapon. Although, Korea had successfully demonstrated the use of rockets as firearms in the fifteenth century, there had been no effort to present the historical development of the early Korean rockets in a paper which will be useful to both historians and scientists. The book entitled Kuk Cho Ore Sorye (1474) in the Korean language provided extensive rocket system description, however it required considerable research to interpret them. This paper is the first study of early Korean rockets and launchers. The major effort in this study is directed toward the development of design concepts and details of early Korean rockets. Also, to substantiate support of the historical data presented, some versions of the early Korean rockets were made according to their specifications and fired successfully by the author in 1981.

  19. State-space analysis of the dynamic characteristics of a variable thrust liquid propellant rocket engine

    Science.gov (United States)

    Zhang, Yu-Lin

    This paper states the application of state-space method to the analysis of the dynamic characteristics of a variable thrust liquid propellant rocket engine and presents a set of state equations for describing the dynamic process of the engine. An efficient numerical method for solving these system equations is developed. The theoretical solutions agree well with the experimental data. The analysis leads to the following conclusion: the set coefficient of the pulse width, the working frequency of the solenoid valves and the deviation of the critical working points of these valves are important parameters for determining the dynamic response time and the control precision of this engine. The methods developed in this paper may be used effectively in the analysis of dynamic characteristics of variable thrust liquid propellant rocket engines.

  20. Pulse subtraction Doppler

    Science.gov (United States)

    Mahue, Veronique; Mari, Jean Martial; Eckersley, Robert J.; Caro, Colin G.; Tang, Meng-Xing

    2010-01-01

    Recent advances have demonstrated the feasibility of molecular imaging using targeted microbubbles and ultrasound. One technical challenge is to selectively detect attached bubbles from those freely flowing bubbles and surrounding tissue. Pulse Inversion Doppler is an imaging technique enabling the selective detection of both static and moving ultrasound contrast agents: linear scatterers generate a single band Doppler spectrum, while non-linear scatterers generate a double band spectrum, one being uniquely correlated with the presence of contrast agents and non-linear tissue signals. We demonstrate that similar spectrums, and thus the same discrimination, can be obtained through a Doppler implementation of Pulse Subtraction. This is achieved by reconstructing a virtual echo using the echo generated from a short pulse transmission. Moreover by subtracting from this virtual echo the one generated from a longer pulse transmission, it is possible to fully suppress the echo from linear scatterers, while for non-linear scatterers, a signal will remain, allowing classical agent detection. Simulations of a single moving microbubble and a moving linear scatterer subject to these pulses show that when the virtual echo and the long pulse echo are used to perform pulsed Doppler, the power Doppler spectrum allows separation of linear and non-linear moving scattering. Similar results are obtained on experimental data acquired on a flow containing either microbubble contrast agents or linear blood mimicking fluid. This new Doppler method constitutes an alternative to Pulse Inversion Doppler and preliminary results suggest that similar dual band spectrums could be obtained by the combination of any non-linear detection technique with Doppler demodulation.

  1. Regression Rate Study in HTPB/GOX Hybrid Rocket Motors.

    OpenAIRE

    Philmon George; Krishnan, S; Lalitha Ramachandran; P. M. Varkey; Raveendran, M.

    1996-01-01

    The theoretical and experimenIal studies on hybrid rocket motor combustion research are briefly reviewed and the need for a clear understanding of hybrid rocket fuel regression rate mechanism is brought out. A test facility established at the Indian Institute of Technology, Madras, for hybrid rocket motor research study is described.The results of an experimental study on hydroxyl terminated polybutadiene and gaseous oxygen hybrid rocket motor are presented. Fuel grains with ammonium perchlor...

  2. Low Cost Nuclear Thermal Rocket Cermet Fuel Element Environment Testing

    Science.gov (United States)

    Bradley, D. E.; Mireles, O. R.; Hickman, R. R.

    2011-01-01

    Deep space missions with large payloads require high specific impulse and relatively high thrust to achieve mission goals in reasonable time frames.1,2 Conventional storable propellants produce average specific impulse. Nuclear thermal rockets capable of producing high specific impulse are proposed. Nuclear thermal rockets employ heat produced by fission reaction to heat and therefore accelerate hydrogen, which is then forced through a rocket nozzle providing thrust. Fuel element temperatures are very high (up to 3000 K), and hydrogen is highly reactive with most materials at high temperatures. Data covering the effects of high-temperature hydrogen exposure on fuel elements are limited.3 The primary concern is the mechanical failure of fuel elements that employ high-melting-point metals, ceramics, or a combination (cermet) as a structural matrix into which the nuclear fuel is distributed. The purpose of the testing is to obtain data to assess the properties of the non-nuclear support materials, as-fabricated, and determine their ability to survive and maintain thermal performance in a prototypical NTR reactor environment of exposure to hydrogen at very high temperatures. The fission process of the planned fissile material and the resulting heating performance is well known and does not therefore require that active fissile material be integrated in this testing. A small-scale test bed designed to heat fuel element samples via non-contact radio frequency heating and expose samples to hydrogen is being developed to assist in optimal material and manufacturing process selection without employing fissile material. This paper details the test bed design and results of testing conducted to date.

  3. A retrospective on early cryogenic primary rocket subsystem designs as integrated into rocket-based combined-cycle (RBCC) engines

    Science.gov (United States)

    Escher, William J. D.; Schnurstein, Robert E.

    1993-06-01

    A study (Escher and Flornes, 1966) of aerospace propulsion systems for a fully reusable earth-to-orbit space transport application that was performed in 1965-67 is reviewed. The present review provides a detailed, subject-focused technical retrospective on a key subsystem element of the rocket-based combined-cycle (RBCC) class of aerospace propulsion systems. The RBCC concept is considered to be a leading candidate propulsion approach for either SSTO or two-stage-to-orbit space transportaion applications.

  4. Facility for cold flow testing of solid rocket motor models

    Science.gov (United States)

    Bacchus, D. L.; Hill, O. E.; Whitesides, R. Harold

    1992-02-01

    A new cold flow test facility was designed and constructed at NASA Marshall Space Flight Center for the purpose of characterizing the flow field in the port and nozzle of solid propellant rocket motors (SRM's). A National Advisory Committee was established to include representatives from industry, government agencies, and universities to guide the establishment of design and instrumentation requirements for the new facility. This facility design includes the basic components of air storage tanks, heater, submicron filter, quiet control valve, venturi, model inlet plenum chamber, solid rocket motor (SRM) model, exhaust diffuser, and exhaust silencer. The facility was designed to accommodate a wide range of motor types and sizes from small tactical motors to large space launch boosters. This facility has the unique capability of testing ten percent scale models of large boosters such as the new Advanced Solid Rocket Motor (ASRM), at full scale motor Reynolds numbers. Previous investigators have established the validity of studying basic features of solid rocket motor development programs include the acquisition of data to (1) directly evaluate and optimize the design configuration of the propellant grain, insulation, and nozzle; and (2) provide data for validation of the computational fluid dynamics, (CFD), analysis codes and the performance analysis codes. A facility checkout model was designed, constructed, and utilized to evaluate the performance characteristics of the new facility. This model consists of a cylindrical chamber and converging/diverging nozzle with appropriate manifolding to connect it to the facility air supply. It was designed using chamber and nozzle dimensions to simulate the flow in a 10 percent scale model of the ASRM. The checkout model was recently tested over the entire range of facility flow conditions which include flow rates from 9.07 to 145 kg/sec (20 to 320 Ibm/sec) and supply pressure from 5.17 x 10 exp 5 to 8.27 x 10 exp 6 Pa. The

  5. Design and performance of high-pressure PLANET beamline at pulsed neutron source at J-PARC

    Energy Technology Data Exchange (ETDEWEB)

    Hattori, T.; Sano-Furukawa, A. [J-PARC Center, Japan Atomic Energy Agency, Tokai, Naka, Ibaraki 319-1195 (Japan); Quantum Beam Science Center, Japan Atomic Energy Agency, Tokai, Naka, Ibaraki 319-1195 (Japan); Arima, H. [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Komatsu, K. [Geochemical Research Center, Graduate School of Science, The University of Tokyo, Tokyo 113-0033 (Japan); Yamada, A. [University of Shiga Prefecture, Shiga 522-8533 (Japan); Inamura, Y.; Nakatani, T. [J-PARC Center, Japan Atomic Energy Agency, Tokai, Naka, Ibaraki 319-1195 (Japan); Seto, Y. [Graduate School of Science, Kobe University, Kobe 657-8501 (Japan); Nagai, T. [Faculty of Science, Hokkaido University, Sapporo 060-0810 (Japan); Utsumi, W. [Quantum Beam Science Center, Japan Atomic Energy Agency, Tokai, Naka, Ibaraki 319-1195 (Japan); Iitaka, T. [Computational Astrophysics Laboratory, RIKEN, Saitama 351-0198 (Japan); Kagi, H. [Geochemical Research Center, Graduate School of Science, The University of Tokyo, Tokyo 113-0033 (Japan); Katayama, Y. [Quantum Beam Science Center, Japan Atomic Energy Agency, Tokai, Naka, Ibaraki 319-1195 (Japan); Inoue, T. [Geodynamic Research Center, Ehime University, Matsuyama 790-8577 (Japan); Otomo, T. [J-PARC Center, Japan Atomic Energy Agency, Tokai, Naka, Ibaraki 319-1195 (Japan); Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki 205-001 (Japan); Suzuya, K. [J-PARC Center, Japan Atomic Energy Agency, Tokai, Naka, Ibaraki 319-1195 (Japan); Kamiyama, T. [J-PARC Center, Japan Atomic Energy Agency, Tokai, Naka, Ibaraki 319-1195 (Japan); Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki 205-001 (Japan); Arai, M. [J-PARC Center, Japan Atomic Energy Agency, Tokai, Naka, Ibaraki 319-1195 (Japan); Yagi, T. [Geochemical Research Center, Graduate School of Science, The University of Tokyo, Tokyo 113-0033 (Japan)

    2015-04-21

    PLANET is a time-of-flight (ToF) neutron beamline dedicated to high-pressure and high-temperature experiments. The large six-axis multi-anvil high-pressure press designed for ToF neutron diffraction experiments enables routine data collection at high pressures and high temperatures up to 10 GPa and 2000 K, respectively. To obtain clean data, the beamline is equipped with the incident slits and receiving collimators to eliminate parasitic scattering from the high-pressure cell assembly. The high performance of the diffractometer for the resolution (Δd/d~0.6%) and the accessible d-spacing range (0.2–8.4 Å) together with low-parasitic scattering characteristics enables precise structure determination of crystals and liquids under high pressure and temperature conditions.

  6. High-speed pulse-shape generator, pulse multiplexer

    Science.gov (United States)

    Burkhart, Scott C.

    2002-01-01

    The invention combines arbitrary amplitude high-speed pulses for precision pulse shaping for the National Ignition Facility (NIF). The circuitry combines arbitrary height pulses which are generated by replicating scaled versions of a trigger pulse and summing them delayed in time on a pulse line. The combined electrical pulses are connected to an electro-optic modulator which modulates a laser beam. The circuit can also be adapted to combine multiple channels of high speed data into a single train of electrical pulses which generates the optical pulses for very high speed optical communication. The invention has application in laser pulse shaping for inertial confinement fusion, in optical data links for computers, telecommunications, and in laser pulse shaping for atomic excitation studies. The invention can be used to effect at least a 10.times. increase in all fiber communication lines. It allows a greatly increased data transfer rate between high-performance computers. The invention is inexpensive enough to bring high-speed video and data services to homes through a super modem.

  7. Influence of Rocket Engine Characteristics on Shaft Sealing Technology Needs

    Science.gov (United States)

    Keba, John E.

    1999-01-01

    This paper presents viewgraphs of The Influence of Rocket Engine Characteristics on Shaft Sealing Technology Needs. The topics include: 1) Rocket Turbomachinery Shaft Seals (Inter-Propellant-Seal (IPS) Systems, Lift-off Seal Systems, and Technology Development Needs); 2) Rocket Engine Characteristics (Engine cycles, propellants, missions, etc., Influence on shaft sealing requirements); and 3) Conclusions.

  8. 14 CFR 437.67 - Tracking a reusable suborbital rocket.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Tracking a reusable suborbital rocket. 437... a reusable suborbital rocket. A permittee must— (a) During permitted flight, measure in real time the position and velocity of its reusable suborbital rocket; and (b) Provide position and...

  9. Specific Impulses Losses in Solid Propellant Rockets

    Science.gov (United States)

    1974-12-17

    to use the collision function form proposed by Golovin to simplify this production term: 4C><=) <P- .: Accordingly: m hence, by integration: Now, we...November 21, 1940 in Paris, Seine. VFirst Thesis. "Contribution to the Study of Specific i Impulse Loss in Solid Propellant Rockets." Second Thesis

  10. An Analysis of Rocket Propulsion Testing Costs

    Science.gov (United States)

    Ramirez, Carmen; Rahman, Shamim

    2010-01-01

    The primary mission at NASA Stennis Space Center (SSC) is rocket propulsion testing. Such testing is commonly characterized as one of two types: production testing for certification and acceptance of engine hardware, and developmental testing for prototype evaluation or research and development (R&D) purposes. For programmatic reasons there is a continuing need to assess and evaluate the test costs for the various types of test campaigns that involve liquid rocket propellant test articles. Presently, in fact, there is a critical need to provide guidance on what represents a best value for testing and provide some key economic insights for decision-makers within NASA and the test customers outside the Agency. Hence, selected rocket propulsion test databases and references have been evaluated and analyzed with the intent to discover correlations of technical information and test costs that could help produce more reliable and accurate cost projections in the future. The process of searching, collecting, and validating propulsion test cost information presented some unique obstacles which then led to a set of recommendations for improvement in order to facilitate future cost information gathering and analysis. In summary, this historical account and evaluation of rocket propulsion test cost information will enhance understanding of the various kinds of project cost information; identify certain trends of interest to the aerospace testing community.

  11. The rocket problem in general relativity

    CERN Document Server

    Henriques, Pedro G

    2011-01-01

    We derive the covariant optimality conditions for rocket trajectories in general relativity, with and without a bound on the magnitude of the proper acceleration. The resulting theory is then applied to solve two specific problems: the minimum fuel consumption transfer between two galaxies in a FLRW model, and between two stable circular orbits in the Schwarzschild spacetime.

  12. NASA Sounding Rocket Program educational outreach

    Science.gov (United States)

    Eberspeaker, P. J.

    2005-08-01

    Educational and public outreach is a major focus area for the National Aeronautics and Space Administration (NASA). The NASA Sounding Rocket Program (NSRP) shares in the belief that NASA plays a unique and vital role in inspiring future generations to pursue careers in science, mathematics, and technology. To fulfill this vision, the NASA Sounding Rocket Program engages in a host of student flight projects providing unique and exciting hands-on student space flight experiences. These projects include single stage Orion missions carrying "active" high school experiments and "passive" Explorer School modules, university level Orion and Terrier-Orion flights, and small hybrid rocket flights as part of the Small-scale Educational Rocketry Initiative (SERI) currently under development. Efforts also include educational programs conducted as part of major campaigns. The student flight projects are designed to reach students ranging from Kindergarteners to university undergraduates. The programs are also designed to accommodate student teams with varying levels of technical capabilities - from teams that can fabricate their own payloads to groups that are barely capable of drilling and tapping their own holes. The program also conducts a hands-on student flight project for blind students in collaboration with the National Federation of the Blind. The NASA Sounding Rocket Program is proud of its role in inspiring the "next generation of explorers" and is working to expand its reach to all regions of the United States and the international community as well.

  13. Straw Rockets Are out of This World

    Science.gov (United States)

    Gillman, Joan

    2013-01-01

    To capture students' excitement and engage their interest in rocketships and visiting planets in the solar system, the author designed lessons that give students the opportunity to experience the joys and challenges of developing straw rockets, and then observing which design can travel the longest distance. The lessons are appropriate for…

  14. Government Relations: It's Not Rocket Science

    Science.gov (United States)

    Radway, Mike

    2007-01-01

    Many people in the early childhood education field are afraid of government relations work, intimidated by politicians, and believe the whole process is unseemly. The author asserts that they should not be afraid nor be intimidated because government relations is not rocket science and fundamentally officeholders are no different from the rest of…

  15. Simulation of Airplane and Rocket Trajectories

    Science.gov (United States)

    Wahbah, Magdy M.; Berning, Michael J.; Choy, Tony S.

    1987-01-01

    Simulation and Optimization of Rocket Trajectories program (SORT) contains comprehensive mathematical models for simulating aircraft dynamics, freely falling objects, and many types of ballistic trajectories. Provides high-fidelity, three-degrees-of-freedom simulation for atmospheric and exoatmospheric flight. It numerically models vehicle subsystems and vehicle environment. Used for wide range of simulations. Written in machine-independent FORTRAN 77.

  16. Scaled Rocket Testing in Hypersonic Flow

    Science.gov (United States)

    Dufrene, Aaron; MacLean, Matthew; Carr, Zakary; Parker, Ron; Holden, Michael; Mehta, Manish

    2015-01-01

    NASA's Space Launch System (SLS) uses four clustered liquid rocket engines along with two solid rocket boosters. The interaction between all six rocket exhaust plumes will produce a complex and severe thermal environment in the base of the vehicle. This work focuses on a recent 2% scale, hot-fire SLS base heating test. These base heating tests are short-duration tests executed with chamber pressures near the full-scale values with gaseous hydrogen/oxygen engines and RSRMV analogous solid propellant motors. The LENS II shock tunnel/Ludwieg tube tunnel was used at or near flight duplicated conditions up to Mach 5. Model development was strongly based on the Space Shuttle base heating tests with several improvements including doubling of the maximum chamber pressures and duplication of freestream conditions. Detailed base heating results are outside of the scope of the current work, rather test methodology and techniques are presented along with broader applicability toward scaled rocket testing in supersonic and hypersonic flow.

  17. Infrared spectroradiometer for rocket exhaust analysis

    Science.gov (United States)

    Herget, W. F.

    1968-01-01

    Infrared spectroradiometer measures high-resolution spectral absorption, emission, temperature, and concentration of chemical species in radically symmetric zones of the exhaust plumes of large rocket engines undergoing static firing tests. Measurements are made along predetermined lines of sight through the plume.

  18. Rocketing into the future the history and technology of rocket planes

    CERN Document Server

    van Pelt, Michel

    2012-01-01

    Rocketing into the Future journeys into the exciting world of rocket planes, examining the exotic concepts and actual flying vehicles that have been devised over the last one hundred years. Lavishly illustrated with over 150 photographs, it recounts the history of rocket planes from the early pioneers who attached simple rockets on to their wooden glider airplanes to the modern world of high-tech research vehicles. The book then looks at the possibilities for the future. The technological and economic challenges of the Space Shuttle proved insurmountable, and thus the program was unable to fulfill its promise of low-cost access to space. However, the burgeoning market of suborbital space tourism may yet give the necessary boost to the development of a truly reusable spaceplane.

  19. Pulse plating

    CERN Document Server

    Hansal, Wolfgang E G; Green, Todd; Leisner, Peter; Reichenbach, Andreas

    2012-01-01

    The electrodeposition of metals using pulsed current has achieved practical importance in recent years. Although it has long been known that changes in potential, with or without polarity reversal, can significantly affect the deposition process, the practical application of this has been slow to be adopted. This can largely be explained in terms of the complex relationship between the current regime and its effect on the electrodeposition process. In order to harness these effects, an understanding of the anodic and cathodic electrochemical processes is necessary, together with the effects of polarity reversal and the rate of such reversals. In this new monograph, the basics of metal electrodeposition from solution are laid out in great detail in seven distinct chapters. With this knowledge, the reader is able to predict how a given pulse train profile can be adopted to achieve a desired outcome. Equally important is the choice of a suitable rectifier and the ancillary control circuits to enable pulse platin...

  20. Channel electron multiplier operated on a sounding rocket without a cryogenic vacuum pump from 120 - 75 km altitude

    Science.gov (United States)

    Dickson, S.; Gausa, M. A.; Robertson, S. H.; Sternovsky, Z.

    2012-12-01

    We demonstrate that a channel electron multiplier (CEM) can be operated on a sounding rocket in the pulse-counting mode from 120 km to 75 km altitude without the cryogenic evacuation used in the past. Evacuation of the CEM is provided only by aerodynamic flow around the rocket. This demonstration is motivated by the need for additional flights of mass spectrometers to clarify the fate of metallic compounds and ions ablated from micrometeorites and their possible role in the nucleation of noctilucent clouds. The CEMs were flown as guest instruments on the two sounding rockets of the CHAMPS (CHarge And mass of Meteoritic smoke ParticleS) rocket campaign which were launched into the mesosphere in October 2011 from Andøya Rocket Range, Norway. Modeling of the aerodynamic flow around the payload with Direct Simulation Monte-Carlo (DSMC) code showed that the pressure is reduced below ambient in the void beneath an aft-facing surface. An enclosure containing the CEM was placed above an aft-facing deck and a valve was opened on the downleg to expose the CEM to the aerodynamically evacuated region below. The CEM operated successfully from apogee down to ~75 km. A Pirani gauge confirmed pressures reduced to as low as 20% of ambient with the extent of reduction dependent upon altitude and velocity. Additional DSMC simulations indicate that there are alternate payload designs with improved aerodynamic pumping for forward mounted instruments such as mass spectrometers.