Hydrogen Peroxide-Based Gas Generator Design and Performance Testing as an Aircraft Emergency Power Unit

Author(s):  
Gyaebyung Yang ◽  
Daejong Park ◽  
Chun Taek Kim ◽  
Sejin Kwon

Hydrazine monopropellant is often used with a spontaneous catalyst a high-performance aircraft emergency power unit (EPU) and in aerospace propulsion; however, it is toxic and requires special handling. A hydrogen peroxide (H2O2)-based gas generator, which is suitable for a new family of environmentally friendly monopropellants and is a substitute for toxic hydrazine in EPUs, is introduced in this study. A MnO2/Al2O3 catalyst for H2O2 decomposition, superior to silver catalysts at normal starting and reactivity capabilities, was selected and developed. The performance tests of coupling the gas generator with a turbocharger showed acceptable results for an aircraft EPU with decomposition above 90%, 37 kW maximum turbine output power, and a maximum starting delay of 1.2 s during normal starting operation. The gas generator also demonstrated satisfactory performance during repeated pulse operation at a pulse duration of 3 s and 60 s under various output conditions.

1997 ◽  
Vol 1583 (1) ◽  
pp. 106-111 ◽  
Author(s):  
Donald E. Watson ◽  
Andrew Johnson ◽  
David Jared

Guidelines for the new hot-mix asphalt design system, Superpave, were developed under the Strategic Highway Research Program. One of the most controversial components of this system is the aggregate gradation restricted zone. This restricted zone was adopted as a gradation specification primarily to deter the use of high levels of natural sand in high-performance mixes. By designing mixes with gradations that avoid the restricted zone (i.e., limit natural sand), the internal strength provided by internal friction could be improved. Some agencies question the validity of the restricted zone. The specified gradations of many current mixes contain bands that enter the restricted zone, but the mixes have performed well for years in actual field conditions. The Georgia Department of Transportation (GDOT) currently specifies several standard mixes with gradations that enter the restricted zone and still perform well. These high-performance mixes contain good quality, 100 percent manufactured aggregates and no natural sand. GDOT recommends that the Georgia loaded wheel tester or some other proof tester be incorporated into the mix design process to screen mixes before rejecting them solely because their combined gradation enters the restricted zone. If mixes having combined gradations that enter the restricted zone are categorically rejected, mixes that are economical for the purpose intended may be rejected in the process.


2011 ◽  
Vol 221 ◽  
pp. 364-368 ◽  
Author(s):  
Ping Fu ◽  
Cheng Zhao ◽  
Hua Tian

By using self-made asymmetric AC - DC power supply and adding SiC in ferrous chloride bath, the high performance Fe-SiC iron-based composite coatings were prepared by electrodeposition method. The effect of Phase, composition and SiC particle content on the surface morphology, structure, hardness, wear resistance and corrosion resistance of Fe-SiC composite coatings were studied. The process parameters of Fe-SiC composite plating were optimized. The results showed that the micro-cracks in composite coatings would reduced and the hardness, wear resistance and corrosion resistance will increased by adding SiC particles under the condition of optimum process.


Author(s):  
Anders Hellberg ◽  
Thomas Andersson ◽  
Anders Häggmark

The 37MW Siemens SGT-750 is a high-performance twin-shaft gas turbine with a free power turbine. It can be employed both for power generation and as a mechanical drive. This gas turbine attains a simple cycle efficiency level of 40% and excellent performance in cogeneration as well as in combined cycle. Requirements from the oil & gas industry as well as industrial power generation have been heeded in the design. Since customer earnings are dependant upon turbine availability, uptime has been a major focus. Long service intervals, rapid gas generator exchange and easy access for borescope inspection all guarantee optimized availability. Maintenance work can be performed on site on the installed machine, alternatively the gas generator can be exchanged to minimize downtime. With this solution, maintenance downtime can be cut to a mere 17 days in 17 years. Furthermore, the hot-section blade temperatures can be monitored during operation as a “health check” to ensure availability. The SGT-750 is a “low-emission engine” equipped with a dry low emission (DLE) combustion system minimizing NOx and CO emissions. The high efficiency leads to a reduction of greenhouse gases with the further possibility to reduce the relative CO2-emissions in cogeneration or combined cycle. This paper will describe the development and testing of the SGT-750 gas turbine and the additional features which have been incorporated. A new development process has made it possible to increase uptime and serviceability; special attention has been brought to this aspect during the design phase, as will be highlighted in the paper.


Author(s):  
D. E. Newbury ◽  
R. D. Leapman

Trace constituents, which can be very loosely defined as those present at concentration levels below 1 percent, often exert influence on structure, properties, and performance far greater than what might be estimated from their proportion alone. Defining the role of trace constituents in the microstructure, or indeed even determining their location, makes great demands on the available array of microanalytical tools. These demands become increasingly more challenging as the dimensions of the volume element to be probed become smaller. For example, a cubic volume element of silicon with an edge dimension of 1 micrometer contains approximately 5×1010 atoms. High performance secondary ion mass spectrometry (SIMS) can be used to measure trace constituents to levels of hundreds of parts per billion from such a volume element (e. g., detection of at least 100 atoms to give 10% reproducibility with an overall detection efficiency of 1%, considering ionization, transmission, and counting).


2020 ◽  
pp. 1-12
Author(s):  
Wu Xin ◽  
Qiu Daping

The inheritance and innovation of ancient architecture decoration art is an important way for the development of the construction industry. The data process of traditional ancient architecture decoration art is relatively backward, which leads to the obvious distortion of the digitalization of ancient architecture decoration art. In order to improve the digital effect of ancient architecture decoration art, based on neural network, this paper combines the image features to construct a neural network-based ancient architecture decoration art data system model, and graphically expresses the static construction mode and dynamic construction process of the architecture group. Based on this, three-dimensional model reconstruction and scene simulation experiments of architecture groups are realized. In order to verify the performance effect of the system proposed in this paper, it is verified through simulation and performance testing, and data visualization is performed through statistical methods. The result of the study shows that the digitalization effect of the ancient architecture decoration art proposed in this paper is good.


TAPPI Journal ◽  
2012 ◽  
Vol 11 (7) ◽  
pp. 37-46 ◽  
Author(s):  
PEDRO E.G. LOUREIRO ◽  
SANDRINE DUARTE ◽  
DMITRY V. EVTUGUIN ◽  
M. GRAÇA V.S. CARVALHO

This study puts particular emphasis on the role of copper ions in the performance of hydrogen peroxide bleaching (P-stage). Owing to their variable levels across the bleaching line due to washing filtrates, bleaching reagents, and equipment corrosion, these ions can play a major role in hydrogen peroxide decomposition and be detrimental to polysaccharide integrity. In this study, a Cu-contaminated D0(EOP)D1 prebleached pulp was subjected to an acidic washing (A-stage) or chelation (Q-stage) before the alkaline P-stage. The objective was to understand the isolated and combined role of copper ions in peroxide bleaching performance. By applying an experimental design, it was possible to identify the main effects of the pretreatment variables on the extent of metals removal and performance of the P-stage. The acid treatment was unsuccessful in terms of complete copper removal, magnesium preservation, and control of hydrogen peroxide consumption in the following P-stage. Increasing reaction temperature and time of the acidic A-stage improved the brightness stability of the D0(EOP)D1AP bleached pulp. The optimum conditions for chelation pretreatment to maximize the brightness gains obtained in the subsequent P-stage with the lowest peroxide consumption were 0.4% diethylenetriaminepentaacetic acid (DTPA), 80ºC, and 4.5 pH.


2017 ◽  
Author(s):  
Varun Bheemireddy

The two-dimensional(2D) materials are highly promising candidates to realise elegant and e cient transistor. In the present letter, we conjecture a novel co-planar metal-insulator-semiconductor(MIS) device(capacitor) completely based on lateral 2D materials architecture and perform numerical study of the capacitor with a particular emphasis on its di erences with the conventional 3D MIS electrostatics. The space-charge density features a long charge-tail extending into the bulk of the semiconductor as opposed to the rapid decay in 3D capacitor. Equivalently, total space-charge and semiconductor capacitance densities are atleast an order of magnitude more in 2D semiconductor. In contrast to the bulk capacitor, expansion of maximum depletion width in 2D semiconductor is observed with increasing doping concentration due to lower electrostatic screening. The heuristic approach of performance analysis(2D vs 3D) for digital-logic transistor suggest higher ON-OFF current ratio in the long-channel limit even without third dimension and considerable room to maximise the performance of short-channel transistor. The present results could potentially trigger the exploration of new family of co-planar at transistors that could play a signi significant role in the future low-power and/or high performance electronics.<br>


Author(s):  
Boris A. Sokolov ◽  
Nikolay N. Tupitsyn

The paper presents results of engineering studies and research and development efforts at RSC Energia to analyze and prove the feasibility of using the mass-produced oxygen-hydrocarbon engine 11D58M with 8.5 ton-force thrust as a basis for development of a high-performance multifunctional rocket engine with oxygen cooling and 5 ton-force thrust, which is optimal for upper stages (US), embodying a system that does not include a gas generator. The multi-functionality of the engine implies including in it additional units supporting some functions that are important for US, such as feeding propellant from US tanks to the engine after flying in zero gravity, autonomous control of the engine automatic equipment to support its firing, shutdown, adjustments during burn and emergency protection in case of off-nominal operation, as well as generating torques for controlling the US attitude and stabilizing it during coasting, etc. Replacing conventional engine chamber cooling that uses high-boiling hydrocarbon fuel with the innovative oxygen cooling makes it possible to get rid of the internal film cooling circuits and eliminate their attendant losses of fuel, while the use of the oxygen gasified in the cooling circuit of the chamber to drive the turbo pump assembly permits to design an engine that does not have a gas generator. Key words: Multifunctional rocket engine, oxygen cooling, gas-generatorless design, upper stage.


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