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Sample records for jt9d jet engine

  1. Performance deterioration based on in-service engine data: JT9D jet engine diagnostics program

    Science.gov (United States)

    Sallee, G. P.

    1979-01-01

    Results of analyses of engine performance deterioration trends and levels with respect to service usage are presented. Thirty-two JT9D-7A engines were selected for this purpose. The selection of this engine fleet provided the opportunity of obtaining engine performance data starting before the first flight through initial service such that the trend and levels of engine deterioration related to both short and long term deterioration could be more carefully defined. The performance data collected and analyzed included in-flight, on wing (ground), and test stand prerepair and postrepair performance calibrations with expanded instrumentation where feasible. The results of the analyses of these data were used to: (1) close gaps in previously obtained historical data as well as augment the historical data with more carefully obtained data; (2) refine preliminary models of performance deterioration with respect to usage; (3) establish an understanding of the relationships between ground and altitude performance deterioration trends; (4) refine preliminary recommendations concerning means to reduce and control deterioration; and (5) identify areas where additional effort is required to develop an understanding of complex deterioration issues.

  2. The JT8D and JT9D engine component improvement: Performance improvement program

    Science.gov (United States)

    Gaffin, W. O.

    1982-01-01

    The NASA sponsored Engine Component Improvement - Performance Improvement Program at Pratt & Whitney Aircraft advanced the state of the art of thermal barrier coatings and ceramic seal systems, demonstrated the practicality of an advanced turbine clearance control system and an advanced fan design in the JT9D engine, and demonstrated the advantages of modern cooling, sealing, and aerodynamic designs in the high pressure turbine and compressor of the JT8D engine. Several of these improvements are already in airline service in JT8D and JT9D engines, and others will enter service soon in advanced models of these engines. In addition, the technology advances are being transferred to completely new engine configurations, the PW2037 engine and the NASA sponsored Energy Efficient Engine.

  3. 76 FR 72130 - Airworthiness Directives; Pratt & Whitney JT9D Series Turbofan Engines

    Science.gov (United States)

    2011-11-22

    ... result in an uncontained engine failure and damage to the airplane. Actions Since Existing AD (72 FR... conditions which, if allowed to continue in service, could result in uncontained engine failures. This..., -7H, -7J, -20, and -20J engines; Adding ECIs for web cooling holes and tierod holes in HPT stage...

  4. 76 FR 41144 - Airworthiness Directives; Pratt & Whitney Corp. (PW) JT9D-7R4H1 Turbofan Engines

    Science.gov (United States)

    2011-07-13

    ...-7R4H1 engines containing an HPC shaft with cracks in the thread grooves of the rear shaft. These engines... Rulemaking Title 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety... & Propeller Directorate, Aircraft Certification Service. BILLING CODE 4910-13-P...

  5. 76 FR 77107 - Airworthiness Directives; Pratt & Whitney Corp. (PW) JT9D-7R4H1 Turbofan Engines

    Science.gov (United States)

    2011-12-12

    ... shafts before their certified life limits and establishes a new, lower life-limit for these parts. We are...., East Hartford, CT 06108; phone: (860) 565- 1605. You may review copies of the referenced service... FR 41144). That NPRM proposed to require: For HPC shafts that have more than 4,500...

  6. Jet engine. Strahltriebwerk

    Energy Technology Data Exchange (ETDEWEB)

    Weber, F.J.

    1990-11-15

    A gas turbine axial-flow compressor aggregate is mounted in a jet engine consisting of a high-temperature combustion chamber that is composed of conical rings forming slits and set together to a ring column and reaches up to the propelling nozzle, a compressed-air generator supplying the jet engine with compressed air at subsonic speeds and running into the propelling nozzle and a shell encasing the jet engine while leaving a certain intermediate space. The compressor aggregate has a relatively high fuel consumption and high emission rates, involves high production and maintenance costs and puts the blades at a high risk of overheating. The problem basic to the invention was to install a compressed-air generator in the jet engine that has lower fuel consumption and emission rates and is cheaper to manufacture and to service. The invention provides free-piston compressors for compressed-air generators arranged in a circle around the central high-temperature combustion chamber. The ring of compressors can rotate on bearings against the jet engine shell, so that each compressor can be turned to the bottom and serviced there. The jet engine is suitable as an engine for supersonic aircraft.

  7. Jet Engine Noise Reduction

    Science.gov (United States)

    2009-04-01

    Technology Solutions, Lockheed Martin Robert S. Carnes , M.D. NRAC Member, Battelle Memorial Institute MajGen Paul A. Fratarangelo, USMC (Ret) NRAC...Development, Acquisition) (VADM Architzel). The Naval Research Advisory Committee members (Bowes, Bowler, Carnes and Fratarangelo) have broad...Lockheed Martin ADP Boeing: Jet Engine Noise Reduction for Tactical Fighter Aircraft Mr. Tom Kaemming, K. Viswanathan, Ph . D. Tactical Jet Noise

  8. System identification of jet engines

    Energy Technology Data Exchange (ETDEWEB)

    Sugiyama, N.

    2000-01-01

    System identification plays an important role in advanced control systems for jet engines, in which controls are performed adaptively using data from the actual engine and the identified engine. An identification technique for jet engine using the Constant Gain Extended Kalman Filter (CGEKF) is described. The filter is constructed for a two-spool turbofan engine. The CGEKF filter developed here can recognize parameter change in engine components and estimate unmeasurable variables over whole flight conditions. These capabilities are useful for an advanced Full Authority Digital Electric Control (FADEC). Effects of measurement noise and bias, effects of operating point and unpredicted performance change are discussed. Some experimental results using the actual engine are shown to evaluate the effectiveness of CGEKF filter.

  9. Astrophysics: Cosmic jet engines

    Science.gov (United States)

    Young, Andy

    2010-02-01

    In some galaxies, matter falling onto a supermassive black hole is ejected in narrow jets moving at close to the speed of light. New observations provide insight into the workings of these cosmic accelerators.

  10. Simple thermodynamics of jet engines

    Science.gov (United States)

    Patrício, Pedro; Tavares, José M.

    2010-08-01

    We use the first and second laws of thermodynamics to analyze the behavior of an ideal jet engine. Simple analytical expressions for the thermal efficiency, the overall efficiency, and the reduced thrust are derived. We show that the thermal efficiency depends only on the compression ratio r and on the velocity of the aircraft. The other two performance measures depend also on the ratio of the temperature at the turbine to the inlet temperature in the engine, T3/Ti. An analysis of these expressions shows that it is not possible to choose an optimal set of values of r and T3/Ti that maximize both the overall efficiency and thrust. We study how irreversibilities in the compressor and the turbine decrease the overall efficiency of jet engines and show that this effect is more pronounced for smaller T3/Ti.

  11. Structural integrity of jet engines; Jet engine no kozo kenzensei

    Energy Technology Data Exchange (ETDEWEB)

    Onabe, H. [Ishikawajima-Harima Heavy Indutries, Co. Ltd., Tokyo (Japan)

    1995-02-05

    This paper outlines the structural integrity of jet engines. In turbo-jet aircraft, the accident caused by equipment statistically reaches 12.5%. For a rotor design, a disk, shaft, engine mount, and blade are very important. A technique that evaluates the structural integrity of a fan blade is prescribed. The FOD resistance (resistance against the damage by a foreign substance) is prescribed in the airworthiness examination procedure. In GE, a 3.6-kg drive test that is double the normal test is made for the developed fan blade. The structural integrity of the disk requires a 120% overspeed test and repeated rotation fatigue test. Retirement-for-Cause (RFC) is the concept for lengthen the operating life without damaging the safety of a disk. Non-destructive inspection technology is important for the RFC. The structural integrity of the shaft and engine mount becomes an issue as secondary damage when the blade was broken. Twin-engined aircraft requires an air route through which it can arrive at the airport within 60 minutes by a single engine. 13 refs., 7 figs.

  12. Airframe-Jet Engine Integration Noise

    Science.gov (United States)

    Tam, Christopher; Antcliff, Richard R. (Technical Monitor)

    2003-01-01

    It has been found experimentally that the noise radiated by a jet mounted under the wing of an aircraft exceeds that of the same jet in a stand-alone environment. The increase in noise is referred to as jet engine airframe integration noise. The objectives of the present investigation are, (1) To obtain a better understanding of the physical mechanisms responsible for jet engine airframe integration noise or installation noise. (2) To develop a prediction model for jet engine airframe integration noise. It is known that jet mixing noise consists of two principal components. They are the noise from the large turbulence structures of the jet flow and the noise from the fine scale turbulence. In this investigation, only the effect of jet engine airframe interaction on the fine scale turbulence noise of a jet is studied. The fine scale turbulence noise is the dominant noise component in the sideline direction. Thus we limit out consideration primarily to the sideline.

  13. Engine room cooling system using jet pump

    Energy Technology Data Exchange (ETDEWEB)

    Lim, J.W.; Lee, S.H. [Daewoo Heavy Industries Ltd. (Korea)

    2000-04-01

    Construction machinery includes an engine enclosure separated from a cooling system enclosure by a wall to reduce noise and advance cooling system performance. For this structure, however, the axial fan cannot be of benefit to the engine room, and so the temperature rise in the engine room makes several bad conditions. This paper proposes that hot air in engine room is evacuated by secondary pipe using jet pump. This paper demonstrates the structure and the effect of jet pump and useful guideline on design of area, length, and shape of secondary pipe to maximize the effect of jet pump. (author). 4 refs., 7 figs., 5 tabs.

  14. Detonation Jet Engine. Part 2--Construction Features

    Science.gov (United States)

    Bulat, Pavel V.; Volkov, Konstantin N.

    2016-01-01

    We present the most relevant works on jet engine design that utilize thermodynamic cycle of detonative combustion. Detonation engines of various concepts, pulse detonation, rotational and engine with stationary detonation wave, are reviewed. Main trends in detonation engine development are discussed. The most important works that carried out…

  15. Turbine ram jet engine. Turbinen-Staustrahltriebwerk

    Energy Technology Data Exchange (ETDEWEB)

    Jabs, A.

    1991-04-25

    A turbine ram jet engine is described with a ram compressed air duct, which is formed between an outer duct wall and a housing-like jacket of a basic turbine engine and is to be shut off on the incoming air side with means of shutting off, by which the ram compressed air duct is shut off with the basic engine switched on and the ram jet engine switched off with simultaneous release of suction air into the basic engine. The jacket should form an air shaft opening out polygonally in the direction of the end of the ram compressed air duct on the inlet side and should have penetrations, where the means of shutting off at the penetrations are hinged flaps, which open up the penetrations with the ram jet engine switched on and thus form a shut-off body of the air shaft symmetrically opposite the ram air flow.

  16. Conceptual Design of a Supersonic Jet Engine

    OpenAIRE

    Kareliusson, Joakim; Nordqvist, Melker

    2014-01-01

    This thesis is a response to the request for proposal issued by a joint collaboration between the AIAA Foundation and ASME/IGTI as a student competition to design a new turbofan engine intended for a conceptual supersonic business jet expected to enter service in 2025. Due to the increasing competition in the aircraft industry and the more stringent environmental legislations the new engine is expected to provide a lower fuel burn than the current engine intended for the aircraft to increase ...

  17. The smallest man-made jet engine.

    Science.gov (United States)

    Sanchez, Samuel; Solovev, Alexander A; Harazim, Stefan M; Deneke, Christoph; Mei, Yong Feng; Schmidt, Oliver G

    2011-12-01

    The design of catalytic engines powered by chemical fuels is an exciting and emerging field in multidisciplinary scientific communities. Recent progress in nanotechnology has enabled scientists to shrink the size of macroengines down to microscopic, but yet powerful, engines. Since a couple of years ago, we have reported our progress towards the control and application of catalytic microtubular engines powered by the breakdown of hydrogen peroxide fuel which produces a thrust of oxygen bubbles. Efforts were undertaken in our group to prove whether the fabrication of nanoscale jets is possible. Indeed, the smallest jet engine (600 nm in diameter and 1 picogram of weight) was synthesized based on heteroepitaxially grown layers. These nanojets are able to self-propel in hydrogen peroxide solutions and are promising for the realisation of multiple tasks.

  18. Detonation Jet Engine. Part 1--Thermodynamic Cycle

    Science.gov (United States)

    Bulat, Pavel V.; Volkov, Konstantin N.

    2016-01-01

    We present the most relevant works on jet engine design that utilize thermodynamic cycle of detonative combustion. The efficiency advantages of thermodynamic detonative combustion cycle over Humphrey combustion cycle at constant volume and Brayton combustion cycle at constant pressure were demonstrated. An ideal Ficket-Jacobs detonation cycle, and…

  19. Jet engine noise and infrared plume correlation field campaign

    Science.gov (United States)

    Cunio, Phillip M.; Weber, Reed A.; Knobel, Kimberly R.; Smith, Christine; Draudt, Andy

    2015-09-01

    Jet engine noise can be a health hazard and environmental pollutant, particularly affecting personnel working in close proximity to jet engines, such as airline mechanics. Mitigating noise could reduce the potential for hearing loss in runway workers; however, there exists a very complex relationship between jet engine design parameters, operating conditions, and resultant noise power levels, and understanding and characterizing this relationship is a key step in mitigating jet engine noise effects. We demonstrate initial results highlighting the utility of high-speed imaging (hypertemporal imaging) in correlating the infrared signatures of jet engines with acoustic noise. This paper builds on prior theoretical analysis of jet engine infrared signatures and their potential relationships to jet engine acoustic emissions. This previous work identified the region of the jet plume most likely to emit both in infrared and in acoustic domains, and it prompted the investigation of wave packets as a physical construct tying together acoustic and infrared energy emissions. As a means of verifying these assertions, a field campaign to collect relevant data was proposed, and data collection was carried out with a bank of infrared instruments imaging a T700 turboshaft engine undergoing routine operational testing. The detection of hypertemporal signatures in association with acoustic signatures of jet engines enables the use of a new domain in characterizing jet engine noise. This may in turn enable new methods of predicting or mitigating jet engine noise, which could lead to socioeconomic benefits for airlines and other operators of large numbers of jet engines.

  20. Dynamic characteristics and control of jet engines. Jet engine no dynamics to seigyo

    Energy Technology Data Exchange (ETDEWEB)

    Sugiyama, N. (National Aerospace Lab., Chofu, Tokyo (Japan))

    1993-06-10

    The recent controller of a jet engine is called as Full Authority Digital Engine Controller (FADEC). This means that the whole operation from starting to shut down of an engine is carried out by the electric digital control. Many studies on the control of a jet engine by the electric digital control have been conducted since the past, this advantages were also clarified, but, since the reliability of electrical machines was low, this was not put into use at once. However, FADEC became possible since the technical reform concerning to the increasing reliability and environment-resisting property, small type with low weight and low cost of electrical machines was performed. In this paper, FADEC system was summarized, in connection with this system, studies on the dynamics and multi-variables control of a jet engine were described. 15 refs., 11 figs., 1 tab.

  1. Ultra light weight jet engine JR100; Chokeiryo jet engine JR100

    Energy Technology Data Exchange (ETDEWEB)

    Matsuki, M. [Nippon Institute of Technology, Saitama (Japan)

    1999-03-20

    As a part of the jet lift V/STOL research by National Aerospace Laboratory, a study of trial manufacture of ultra light weight jet engine JR 100 started in FY 1964. The study was aimed at obtaining a lift engine for VTOL and founding the base for the future jet lift VTOL, and at taking in the results of the jet engine element study accumulated so far and manufacturing an advanced engine. Decided on the use of domestic materials for JR 100, the materials to be used are almost iron-based ones. Through the efforts for weight reduction in structure and processing, a thrust/weight ratio of 10 was realized. At the same time, the production/processing of light weight materials such as titanium alloys was proceeded with, and by adopting the materials to JR 200 system, a thrust/weight ratio of 15 was realized. Together with these, for the purpose of reducing the fuel consumption rate, studies started on fan for lift fan engine and high temperature turbine (an inlet temperature of 1250 degrees C was achieved), to get low noise/high efficiency fan. By the research results, the basis for jet lift VTOL was established, and it became the basis for the development of turbo fan engine FJR 710. (NEDO)

  2. Biosurface engineering through ink jet printing.

    Science.gov (United States)

    Khan, Mohidus Samad; Fon, Deniece; Li, Xu; Tian, Junfei; Forsythe, John; Garnier, Gil; Shen, Wei

    2010-02-01

    The feasibility of thermal ink jet printing as a robust process for biosurface engineering was demonstrated. The strategy investigated was to reconstruct a commercial printer and take advantage of its colour management interface. High printing resolution was achieved by formulating bio-inks of viscosity and surface tension similar to those of commercial inks. Protein and enzyme denaturation during thermal ink jet printing was shown to be insignificant. This is because the time spent by the biomolecules in the heating zone of the printer is negligible; in addition, the air and substrate of high heat capacity absorb any residual heat from the droplet. Gradients of trophic/tropic factors can serve as driving force for cell growth or migration for tissue regeneration. Concentration gradients of proteins were printed on scaffolds to show the capability of ink jet printing. The printed proteins did not desorb upon prolonged immersion in aqueous solutions, thus allowing printed scaffold to be used under in vitro and in vivo conditions. Our group portrait was ink jet printed with a protein on paper, illustrating that complex biopatterns can be printed on large area. Finally, patterns of enzymes were ink jet printed within the detection and reaction zones of a paper diagnostic.

  3. Jet Engine Exhaust Analysis by Subtractive Chromatography

    Science.gov (United States)

    1978-12-01

    and J. J. Brooks. Development of a portable miniature collection system for the exposure as- sessment within the microenvironment for carcinogens ...65 A-2. Recovery of acrylonitrile from standard sample generation system ...... ............. 66 B-I. Jet engine exhaust sampling and analysis...7 n-Butane 0.16 2.6 minutes 8 Propylene oxide 3.14 52 minutes 9 Acrylonitrile 9.35 2.6 hours 10 Phenanthrene 1.9 x 106 61 years 11 4-Bromodiphenyl

  4. Multiblock grid generation for jet engine configurations

    Science.gov (United States)

    Stewart, Mark E. M.

    1992-01-01

    The goal was to create methods for generating grids with minimal human intervention that are applicable to a wide range of problems and compatible with existing numerical methods and with existing and proposed computers. The following topics that are related to multiblock grid generation are briefly covered in viewgraph form: finding a domain decomposition, dimensioning grids, grid smoothing, manipulating grids and decompositions, and some specializations for jet engine configurations.

  5. Jet Engine Exhaust Nozzle Flow Effector

    Science.gov (United States)

    Turner, Travis L. (Inventor); Cano, Roberto J. (Inventor); Silox, Richard J. (Inventor); Buehrle, Ralph D. (Inventor); Cagle, Christopher M. (Inventor); Cabell, Randolph H. (Inventor); Hilton, George C. (Inventor)

    2014-01-01

    A jet engine exhaust nozzle flow effector is a chevron formed with a radius of curvature with surfaces of the flow effector being defined and opposing one another. At least one shape memory alloy (SMA) member is embedded in the chevron closer to one of the chevron's opposing surfaces and substantially spanning from at least a portion of the chevron's root to the chevron's tip.

  6. Failure analysis of jet engine turbine blade

    OpenAIRE

    MILAN T. JOVANOVIĆ; Vesna Maksimović; Ivana Cvijović-Alagić

    2016-01-01

    Jet engine turbine blade cast by investment precision casting of Ni-base superalloy, which failed during exploatation, was the subject of investigation. Failure analysis was executed applying optical microscopy (OM), transmission electron microscopy (TEM) using replica technique, scaning electron microscopy (SEM) and stress rupture life tests. On the ground of obtained results it was concluded that the failure occurred as a result of structural changes caused by turbine blade overheating abov...

  7. Failure analysis of jet engine turbine blade

    Directory of Open Access Journals (Sweden)

    Milan T. Jovanović

    2016-03-01

    Full Text Available Jet engine turbine blade cast by investment precision casting of Ni-base superalloy, which failed during exploatation, was the subject of investigation. Failure analysis was executed applying optical microscopy (OM, transmission electron microscopy (TEM using replica technique, scaning electron microscopy (SEM and stress rupture life tests. On the ground of obtained results it was concluded that the failure occurred as a result of structural changes caused by turbine blade overheating above the exploitation temperature.

  8. Active Control of Jet Engine Inlet Flows

    Science.gov (United States)

    2007-03-31

    investigation was performed with no pressure applied across the fan. To measure the high-frequency, unsteady jet velocity, an IFA 300 hot - wire anemometry ...flow at the engine face. Recommendations for the measurement devices include hot -film or hot - wire sensors and wall-mounted, high frequency pressure...the blade and creates flow instabilities that convect through the later compressor stages. This report presents a study performed to gain an

  9. Entropy generation and jet engine optimization

    CERN Document Server

    Lucia, Umberto

    2010-01-01

    In 2009, it was shown that, with an original approach to hydrodynamic cavitation, a phenomenological model was realized in order to compute some of the physical parameters needed for the design of the most common technological applications (turbo-machinery, etc.) with an economical saving in planning because this analysis could allow engineers to reduce the experimental tests and the consequent costs in the design process. Here the same approach has been used to obtain range of some physical quantity for jet engine optimization.

  10. On the correlation analysis of electric field inside jet engine

    OpenAIRE

    A Krishna; Khattab, T.; Abdelaziz, A.F.; Guizani, M.

    2014-01-01

    A Simple channel modeling method based on correlation analysis of the electric field inside jet engine is presented. The analysis of the statistical propagation characteristics of electromagnetic field inside harsh jet engine environment is presented by using `Ansys® HFSS'. In this paper, we propose a method to locate the best position for receiving probes inside jet engine with minimum correlation between the receiver points which have strong average electric field. Moreover, a MIMO system c...

  11. Event-Shape Engineering and Jet Quenching

    CERN Document Server

    Christiansen, Peter

    2016-01-01

    Event-Shape Engineering (ESE) is a tool that enables some control of the initial geometry in heavy-ion collisions in a similar way as the centrality enables some control of the number of participants. Utilizing ESE, the path length in and out-of plane can be varied while keeping the medium properties (centrality) fixed. In this proceeding it is argued that this provides additional experimental information about jet quenching. Finally, it is suggested that if ESE studies are done in parallel for light and heavy quarks one can determine, in a model independent way, if the path-length dependence of their quenching differs.

  12. Re-Educating Jet-Engine-Researchers to Stay Relevant

    Science.gov (United States)

    Gal-Or, Benjamin

    2016-06-01

    To stay relevantly supported, jet-engine researchers, designers and operators should follow changing uses of small and large jet engines, especially those anticipated to be used by/in the next generation, JET-ENGINE-STEERED ("JES") fleets of jet drones but fewer, JES-Stealth-Fighter/Strike Aircraft. In addition, some diminishing returns from isolated, non-integrating, jet-engine component studies, vs. relevant, supersonic, shock waves control in fluidic-JES-side-effects on compressor stall dynamics within Integrated Propulsion Flight Control ("IPFC"), and/or mechanical JES, constitute key relevant methods that currently move to China, India, South Korea and Japan. The central roles of the jet engine as primary or backup flight controller also constitute key relevant issues, especially under post stall conditions involving induced engine-stress while participating in crash prevention or minimal path-time maneuvers to target. And when proper instructors are absent, self-study of the JES-STVS REVOLUTION is an updating must, where STVS stands for wing-engine-airframe-integrated, embedded stealthy-jet-engine-inlets, restructured engines inside Stealth, Tailless, canard-less, Thrust Vectoring IFPC Systems. Anti-terror and Airliners Super-Flight-Safety are anticipated to overcome US legislation red-tape that obstructs JES-add-on-emergency-kits-use.

  13. Euler solutions for an unbladed jet engine configuration

    Science.gov (United States)

    Stewart, Mark E. M.

    1992-01-01

    An Euler solution for an axisymmetric jet engine configuration without blade effects is presented. The Euler equations are solved on a multiblock grid which covers a domain including the inlet, bybass duct, core passage, nozzle, and the far field surrounding the engine. The simulation is verified by considering five theoretical properties of the solution. The solution demonstrates both multiblock grid generation techniques and a foundation for a full jet engine throughflow calculation.

  14. IC ENGINE SUPERCHARGING AND EXHAUST GAS RECIRCULATION USING JET COMPRESSOR

    Directory of Open Access Journals (Sweden)

    Adhimoulame Kalaisselvane

    2010-01-01

    Full Text Available Supercharging is a process which is used to improve the performance of an engine by increasing the specific power output whereas exhaust gas recirculation reduces the NOx produced by engine because of supercharging. In a conventional engine, supercharger functions as a compressor for the forced induction of the charge taking mechanical power from the engine crankshaft. In this study, supercharging is achieved using a jet compressor. In the jet compressor, the exhaust gas is used as the motive stream and the atmospheric air as the propelled stream. When high pressure motive stream from the engine exhaust is expanded in the nozzle, a low pressure is created at the nozzle exit. Due to this low pressure, atmospheric air is sucked into the expansion chamber of the compressor, where it is mixed and pressurized with the motive stream. The pressure of the mixed stream is further increased in the diverging section of the jet compressor. A percentage volume of the pressurized air mixture is then inducted back into the engine as supercharged air and the balance is let out as exhaust. This process not only saves the mechanical power required for supercharging but also dilutes the constituents of the engine exhaust gas thereby reducing the emission and the noise level generated from the engine exhaust. The geometrical design parameters of the jet compressor were obtained by solving the governing equations using the method of constant rate of momentum change. Using the theoretical design parameters of the jet compressor, a computational fluid dinamics analysis using FLUENT software was made to evaluate the performance of the jet compressor for the application of supercharging an IC engine. This evaluation turned out to be an efficient diagnostic tool for determining performance optimization and design of the jet compressor. A jet compressor was also fabricated for the application of supercharging and its performance was studied.

  15. Mathematical Model of the Jet Engine Fuel System

    Science.gov (United States)

    Klimko, Marek

    2015-05-01

    The paper discusses the design of a simplified mathematical model of the jet (turbo-compressor) engine fuel system. The solution will be based on the regulation law, where the control parameter is a fuel mass flow rate and the regulated parameter is the rotational speed. A differential equation of the jet engine and also differential equations of other fuel system components (fuel pump, throttle valve, pressure regulator) will be described, with respect to advanced predetermined simplifications.

  16. Mathematical Model of the Jet Engine Fuel System

    Directory of Open Access Journals (Sweden)

    Klimko Marek

    2015-01-01

    Full Text Available The paper discusses the design of a simplified mathematical model of the jet (turbo-compressor engine fuel system. The solution will be based on the regulation law, where the control parameter is a fuel mass flow rate and the regulated parameter is the rotational speed. A differential equation of the jet engine and also differential equations of other fuel system components (fuel pump, throttle valve, pressure regulator will be described, with respect to advanced predetermined simplifications.

  17. Acoustically shielded exhaust system for high thrust jet engines

    Science.gov (United States)

    Carey, John P. (Inventor); Lee, Robert (Inventor); Majjigi, Rudramuni K. (Inventor)

    1995-01-01

    A flade exhaust nozzle for a high thrust jet engine is configured to form an acoustic shield around the core engine exhaust flowstream while supplementing engine thrust during all flight conditions, particularly during takeoff. The flade airflow is converted from an annular 360.degree. flowstream to an arcuate flowstream extending around the lower half of the core engine exhaust flowstream so as to suppress exhaust noise directed at the surrounding community.

  18. Jet engine R and D and I; Watashi to jet engine kenkyu kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Murashima, K. [Ishikawajima-Harima Heavy Industries Co. Ltd., Tokyo (Japan)

    1998-06-10

    My efforts towards at the development of aeroengines since the end of the war are described. The J3-7 engine propelled the T1 trainer plane, and was installed as booster aboard the P2J antisubmarine patrol aircraft. It was the first jet engine that Japan produced after the end of the war, and had been in use until quite recently. I took part in the construction of a prototype of the JR100 series designed to serve as VTOL (vertical take-off and landing) aircraft lift engines, and in the test thereof. As the shift from turbojet to turbofan proceeded, I participated in the development of the FJR710 engine under the guidance of National Aerospace Laboratory, and the product was installed aboard an experimental STOL (short take-off and landing) aircraft Asuka. I next joined a Defense Agency initiative for a reheat turbofan to replace the J3 aboard trainer plane, and the result was the low bypass ratio/high output F3 engine. In 1989, Ministry of International Trade and Industry decided for a large-scale project of developing an engine for a next-generation supersonic transport, and the HYPR (Super/Hypersonic Transport Propulsion System) project was started. The project was participated in by manufacturers from overseas, which were GE, P and W, RR, and SNECMA. The foreign corporations worked on an equal footing with the Japanese parties, and collaboration between the participants was smooth, with each party endeavoring in the field they were good at. The project will be concluded as scheduled in fiscal 1998. (NEDO)

  19. Jet Engine Noise Generation, Prediction and Control. Chapter 86

    Science.gov (United States)

    Huff, Dennis L.; Envia, Edmane

    2004-01-01

    Aircraft noise has been a problem near airports for many years. It is a quality of life issue that impacts millions of people around the world. Solving this problem has been the principal goal of noise reduction research that began when commercial jet travel became a reality. While progress has been made in reducing both airframe and engine noise, historically, most of the aircraft noise reduction efforts have concentrated on the engines. This was most evident during the 1950 s and 1960 s when turbojet engines were in wide use. This type of engine produces high velocity hot exhaust jets during takeoff generating a great deal of noise. While there are fewer commercial aircraft flying today with turbojet engines, supersonic aircraft including high performance military aircraft use engines with similar exhaust flow characteristics. The Pratt & Whitney F100-PW-229, pictured in Figure la, is an example of an engine that powers the F-15 and F-16 fighter jets. The turbofan engine was developed for subsonic transports, which in addition to better fuel efficiency also helped mitigate engine noise by reducing the jet exhaust velocity. These engines were introduced in the late 1960 s and power most of the commercial fleet today. Over the years, the bypass ratio (that is the ratio of the mass flow through the fan bypass duct to the mass flow through the engine core) has increased to values approaching 9 for modern turbofans such as the General Electric s GE-90 engine (Figure lb). The benefits to noise reduction for high bypass ratio (HPBR) engines are derived from lowering the core jet velocity and temperature, and lowering the tip speed and pressure ratio of the fan, both of which are the consequences of the increase in bypass ratio. The HBPR engines are typically very large in diameter and can produce over 100,000 pounds of thrust for the largest engines. A third type of engine flying today is the turbo-shaft which is mainly used to power turboprop aircraft and helicopters

  20. Computer Jet-Engine-Monitoring System

    Science.gov (United States)

    Disbrow, James D.; Duke, Eugene L.; Ray, Ronald J.

    1992-01-01

    "Intelligent Computer Assistant for Engine Monitoring" (ICAEM), computer-based monitoring system intended to distill and display data on conditions of operation of two turbofan engines of F-18, is in preliminary state of development. System reduces burden on propulsion engineer by providing single display of summary information on statuses of engines and alerting engineer to anomalous conditions. Effective use of prior engine-monitoring system requires continuous attention to multiple displays.

  1. Computer Jet-Engine-Monitoring System

    Science.gov (United States)

    Disbrow, James D.; Duke, Eugene L.; Ray, Ronald J.

    1992-01-01

    "Intelligent Computer Assistant for Engine Monitoring" (ICAEM), computer-based monitoring system intended to distill and display data on conditions of operation of two turbofan engines of F-18, is in preliminary state of development. System reduces burden on propulsion engineer by providing single display of summary information on statuses of engines and alerting engineer to anomalous conditions. Effective use of prior engine-monitoring system requires continuous attention to multiple displays.

  2. Turbine ram-jet engine. Turbinen-Staustrahltriebwerk

    Energy Technology Data Exchange (ETDEWEB)

    Wildner, W.

    1990-10-25

    A turbine ram-jet engine with a ram pressure air duct surrounding the basic turbine engine as an annulus is described, in which with the ram jet switched off with simultaneous release of suction air into the basic engine, the supply of ram pressure air is shut off. A suction side air inflow corss section of the basic engine can be released or shut off by axial adjustment of a drop-shaped body relative to a flow divider. A ring slide axially adjustable opposite to this body, should be provided, which shuts off the ram pressure air duct with the incoming crossection of the basic engine open and opens it for the shut-off state of the incoming crossection. Further, the ram pressure air duct should be expanded at the level of shut-off zone formed by a body with local counter-surface contact and the ring slider in the upstream direction.

  3. Diagnosis of the jet-propelled engine by vibration analysis

    OpenAIRE

    Mariusz ŻOKOWSKI; Marek SZCZEKALA; Jarosław SPYCHAŁA

    2009-01-01

    In this paper presented works connected with the preparation of the active experiment with the jet-propelled engine. The experiment was prepared and done at the Air Force Institute of Technology. The main aim of this preparation was the explanation of the causes of the damages of military aerial ships after air incidents, notified damages in the process of exploitation and obtainment of the vibration answer on simulated damages.The exit test of the jet-propelled engine was the point of the re...

  4. Diagnosis of the jet-propelled engine by vibration analysis

    Directory of Open Access Journals (Sweden)

    Mariusz ŻOKOWSKI

    2009-01-01

    Full Text Available In this paper presented works connected with the preparation of the active experiment with the jet-propelled engine. The experiment was prepared and done at the Air Force Institute of Technology. The main aim of this preparation was the explanation of the causes of the damages of military aerial ships after air incidents, notified damages in the process of exploitation and obtainment of the vibration answer on simulated damages.The exit test of the jet-propelled engine was the point of the reference after the repair in the Military Aviation Depot.

  5. Investigating potential correlations between jet engine noise and plume dynamics in the hypertemporal infrared domain

    Science.gov (United States)

    Cunio, Phillip M.; Weber, Reed; Knobel, Kimberly; Wager, Jason; Lopez, Gerardo

    2014-09-01

    Jet engine noise can be a hazard and environmental pollutant, affecting personnel working in close proximity to jet engines. Mitigating the effects of jet engine noise could reduce the potential for hearing loss in runway workers, but engine noise is not yet sufficiently well-characterized that it can easily be mitigated for new engine designs. That is, there exists a very complex relationship between jet engine design parameters, operating conditions, and resultant noise power levels. In this paper, we propose to evaluate the utility of high-speed imaging (also called hypertemporal imaging) in correlating the infrared signatures of jet aircraft engines with acoustic noise from the jet engines. This paper will focus on a theoretical analysis of jet engine infrared signatures, and will define potentially-detectable characteristics of such signatures in the hypertemporal domain. A systematic test campaign to determine whether such signatures actually exist and can be correlated with acoustic jet engine characteristics will be proposed. The detection of any hypertemporal signatures in association with acoustic signatures of jet engines will enable the use of a new domain in characterizing jet engine noise. This may in turn enable new methods of predicting or mitigating jet engine noise, which could lead to benefits for operators of large numbers of jet engines.

  6. Recontouring of Jet Engine Compressor Blades by Flow Simulation

    OpenAIRE

    Herwart Hönen; Matthias Panten

    2001-01-01

    In modern jet propulsion systems the core engine has an essential influence on the total engine performance. Especially the high pressure compressor plays an important role in this scheme. Substantial factors here are losses due to tip clearance effects and aerodynamic airfoil quality. During flight operation the airfoils are subject to wear and tear on the leading edge. These effects cause a shortening of the chord length and the leading edge profiles become deformed. This results in a deter...

  7. Rotor Systems of Aircraft Jet Engines

    Directory of Open Access Journals (Sweden)

    Ján Kamenický

    2000-01-01

    engine's both coaxial rotors, their supports (including their hydrodynamic dampers, and its casing as well. Besides the short description of the engine design peculiarities and of its calculating model, there is also a short description of the used method of calculations, with focus on its peculiarities as well. Finally, some results of calculations and conclusions that follow from them are presented.

  8. Studies on Pulse Jet Engine by Wind Tunnel Testing

    OpenAIRE

    Toshihiro Nakano; Michael Zeutzius; Hideo Miyanishi; Toshiaki Setoguchi; Kenji Kaneko

    2001-01-01

    Simple design and efficiency make pulse jet engines attractive for aeronautical short-term operation applications. An active control system extends the operating range and reduces the fuel consumption considerably so that this old technology might gain a new interest. The results on wind tunnel experiments have been reported together with the impact of combustion mode (pulse or steady) on system performance.

  9. Detonation of CHO working substances in a laser jet engine

    Science.gov (United States)

    Ageichik, A. A.; Repina, E. V.; Rezunkov, Yu. A.; Safronov, A. L.

    2009-03-01

    Laser-induced ablation of materials (including polymers and a variety of polycrystalline substances with a CHO chemical composition) is studied theoretically and experimentally. Based on experimental data, a parametric physicochemical model of detonation of these materials is put forward with the aim to estimate the efficiency of laser thrust formation in jet engines.

  10. Prediction of jet engine parameters for control design using genetic programming

    OpenAIRE

    Martínez-Arellano, G; Cant, R; Nolle, L

    2014-01-01

    The simulation of a jet engine behavior is widely used in many different aspects of the engine development and maintenance. Achieving high quality jet engine control systems requires the iterative use of these simulations to virtually test the performance of the engine avoiding any possible damage on the real engine. Jet engine simulations involve the use of mathematical models which are complex and may not always be available. This paper introduces an approach based on Genetic Programming (G...

  11. Assessment of potential asbestos exposures from jet engine overhaul work.

    Science.gov (United States)

    Mlynarek, S P; Van Orden, D R

    2012-06-01

    Asbestos fibers have been used in a wide variety of products and numerous studies have shown that exposures from the use or manipulation of these products can vary widely. Jet engines contained various components (gaskets, clamps, o-rings and insulation) that contained asbestos that potentially could release airborne fibers during routine maintenance or during an engine overhaul. To evaluate the potential exposures to aircraft mechanics, a Pratt & Whitney JT3D jet engine was obtained and overhauled by experienced mechanics using tools and work practices similar to those used since the time this engine was manufactured. This study has demonstrated that the disturbance of asbestos-containing gaskets, o-rings, and other types of asbestos-containing components, while performing overhaul work to a jet engine produces very few airborne fibers, and that virtually none of these aerosolized fibers is asbestos. The overhaul work was observed to be dirty and oily. The exposures to the mechanics and bystanders were several orders of magnitude below OSHA exposure regulations, both current and historic. The data presented underscore the lack of risk to the health of persons conducting this work and to other persons in proximity to it from airborne asbestos.

  12. UV laser spectroscopic measurements in jet engine combustion exit flows

    Energy Technology Data Exchange (ETDEWEB)

    Shirley, J.A. (United Technologies Research Center, East Hartford, CT (United States))

    1992-01-01

    Laser diagnostic measurements, which are excited with a narrowband krypton fluoride laser, have been made at the exit of a jet engine combustor. Spectra of Raman scattering and laser induced fluorescence were measured with a 0.5 meter spectrograph equipped with a diode array detector. For these demonstration tests, the combustor was operated at two flow rates including conditions corresponding to the 90 percent power level, with jet fuel and methane. Nitrogen Raman spectra are free of band interference. However, the signal levels are lower than expected. Sources of signal losses are discussed. 27 refs.

  13. Application of numerical analysis to jet engine combustor design

    Energy Technology Data Exchange (ETDEWEB)

    To, H. (Ishikawajima-Harima Heavy Industries Co. Ltd., Tokyo (Japan))

    1991-04-01

    The design and development process of jet engine combustors in Ishikawajima-Harima Heavy Industries Co., Ltd. was presented which is featured by iterated numerical analyses in earlier stages of design. The analytical methods used, models applied and features were given together with verification results of numerical analyses of a velocity profile in a dump diffuser, flow and temperature distribution in a combustion liner, and liner skin temperature distribution. As examples in design and development of an airblast fuel injector type high temperature combustor, analytical results of the followings were given: flows through a diffuser, flows through a combustion liner, flows through liner cooling slots and liner skin temperature distribution. In addition, results of three-dimensional flow analysis were given in terms of optimization of design parameters for a jet-swirl combustor and calculation of a centrifugal force for a jet-swirl combustor liner as examples. 6 refs., 18 figs., 1 tab.

  14. Jet Engine hot parts IR Analysis Procedure (J-EIRP)

    Science.gov (United States)

    Baumeister, Joseph F.

    1993-01-01

    A thermal radiation analysis method called Jet Engine IR Analysis Procedure (J-EIRP) was developed to evaluate jet engine cavity hot parts source radiation. The objectives behind J-EIRP were to achieve the greatest accuracy in model representation and solution, while minimizing computer resources and computational time. The computer programs that comprise J-EIRP were selected on the basis of their performance, accuracy, and flexibility to solve both simple and complex problems. These programs were intended for use on a personal computer, but include the ability to solve large problems on a mainframe or supercomputer. J-EIRP also provides the user with a tool for developing thermal design experience and engineering judgment through analysis experimentation, while using minimal computer resources. A sample jet engine cavity analysis demonstrates the procedure and capabilities within J-EIRP, and is compared to a simplified method for approximating cavity radiation. The goal is to introduce the terminology and solution process used in J-EIRP and to provide insight into the radiation heat transfer principles used in this procedure.

  15. Entropy generation and jet engine optimization

    OpenAIRE

    Lucia, Umberto

    2010-01-01

    In 2009, it was shown that, with an original approach to hydrodynamic cavitation, a phenomenological model was realized in order to compute some of the physical parameters needed for the design of the most common technological applications (turbo-machinery, etc.) with an economical saving in planning because this analysis could allow engineers to reduce the experimental tests and the consequent costs in the design process. Here the same approach has been used to obtain range of some physical ...

  16. Directional transport of impinging capillary jet on wettability engineered surfaces

    Science.gov (United States)

    Ghosh, Aritra; Chatterjee, Souvick; Sinha Mahapatra, Pallab; Ganguly, Ranjan; Megaridis, Constantine

    2015-11-01

    Impingement of capillary jet on a surface is important for applications like heat transfer, or for liquid manipulation in bio-microfluidic devices. Using wettability engineered surfaces, we demonstrate pump-less and directional transport of capillary jet on a flat surface. Spatial contrast of surface energy and a wedge-shape geometry of the wettability confined track on the substrate facilitate formation of instantaneous spherical bulges upon jet impingement; these bulges are further transported along the superhydrophilic tracks due to Laplace pressure gradient. Critical condition warranted for formation of liquid bulge along the varying width of the superhydrophilic track is calculated analytically and verified experimentally. The work throws light on novel fluid phenomena of unidirectional jet impingement on wettability confined surfaces and provides a platform for innovative liquid manipulation technique for further application. By varying the geometry and wettability contrast on the surface, one can achieve volume flow rates of ~ O(100 μL/sec) and directionally guided transport of the jet liquid, pumplessly at speeds of ~ O(10cm/sec).

  17. Application of numerical analysis to jet engine combustor design. Jet engine nenshoki sekkei eno suchi kaiseki no tekiyo

    Energy Technology Data Exchange (ETDEWEB)

    Fuji, H. (Ishikawajima-Harima Heavy Industries, Co. Ltd., Tokyo (Japan))

    1990-11-01

    Numerical methods are applied in practice to complement and support jet engine combustor design and development. Part of the conventional design-trial fabrication-testing performance evaluation cycle replaced by iterated numerical analysis applied in a preliminary cycle of design-evaluation, undertaken before proceeding to actual trial fabrication testing and final evaluation. Presented examples are of numerical methods applied to design/development of a high temperature combustor of airblast fuel injector type, in which analysis is undertaken of flows through diffuser and through combustion liner, of temperature distributions, of flows through liner cooling slots, and liner skin temperature distributions. Furthermore, results of three-dimensional flow analysis are applied to optimizing the design parameters of a jet-swirl combustor and to calculation of the centrifugal force in a jet swirl combustion liner. 3 refs., 18 figs., 1 tab.

  18. Micro-Jet Test Facility for Aerospace Propulsion Engineering Education

    OpenAIRE

    López Juste, Gregorio; Montañés García, José Luis; Velázquez, A.

    2009-01-01

    This paper describes the methodology that has been developed and implemented at the School ofAeronautics (ETSIA) of the Universidad Politecnica de Madrid (UPM) to familiarize aerospaceengineering students with the operation of real complex jet engine systems. This methodology has atwo-pronged approach: students carry out preparatory work by using, first, a gas turbineperformance prediction numerical code; then they validate their assumptions and results on anexperimental test rig. When lookin...

  19. Numerical simulation of tangling in jet engine turbines

    OpenAIRE

    Cendón Franco, David Angel; Erice Echávarri, Borja; Galvez Diaz-Rubio, Francisco; Sanchez Galvez, Vicente

    2012-01-01

    The numerical analysis of certain safety related problems presents serious difficulties, since the large number of components present leads to huge finite elementmodels that can only be solved by using large and expensive computers or by making rough approaches to the problem. Tangling, or clashing, in the turbine of a jet engine airplane is an example of such problems. This is caused by the crash and friction between rotor and stator blades in the turbine after an eventual shaft failure. Whe...

  20. Studies on Pulse Jet Engine by Wind Tunnel Testing

    Directory of Open Access Journals (Sweden)

    Toshihiro Nakano

    2001-01-01

    Full Text Available Simple design and efficiency make pulse jet engines attractive for aeronautical short-term operation applications. An active control system extends the operating range and reduces the fuel consumption considerably so that this old technology might gain a new interest. The results on wind tunnel experiments have been reported together with the impact of combustion mode (pulse or steady on system performance.

  1. Jet-Engine Exhaust Nozzle With Thrust-Directing Flaps

    Science.gov (United States)

    Wing, David J.

    1996-01-01

    Convergent/divergent jet-engine exhaust nozzle has cruciform divergent passage containing flaps that move to deflect flow of exhaust in either or both planes perpendicular to main fore-and-aft axis of undeflected flow. Prototype of thrust-vector-control nozzles installed in advanced, high-performance airplanes to provide large pitching (usually, vertical) and yawing (usually, horizontal) attitude-control forces independent of attitude-control forces produced by usual aerodynamic control surfaces.

  2. Laser pointing in the vicinity of jet engine plumes

    Science.gov (United States)

    Schleijpen, Ric H. M. A.

    2009-09-01

    Target tracking and laser-based pointing from airborne platforms can be degraded significantly by the propagation environment around an airborne platform including zones of severe turbulence generated by rotor downwash and engine exhausts. This is the topic of the EDA study group ERG 108.019 on "Laser beam propagation and imaging through severe environments". This paper reports on experiments on optical propagation in the vicinity of a plume of a scaled down jet engine, performed by this co-operation group. The group is also working on methods for estimating the extent of the turbulence effects on the tracking and pointing performance under these conditions.

  3. 78 FR 7464 - Large Scale Networking (LSN) ; Joint Engineering Team (JET)

    Science.gov (United States)

    2013-02-01

    ... Large Scale Networking (LSN) ; Joint Engineering Team (JET) AGENCY: The Networking and Information... research networking and networking to support science applications. The JET reports to the Large Scale Networking (LSN) Coordinating Group (CG). Public Comments: The government seeks individual input;...

  4. Combustion instability investigations on the BR710 jet engine

    Energy Technology Data Exchange (ETDEWEB)

    Konrad, W.; Brehm, N.; Kameier, F. [BMW Rolls-Royce AeroEngines, Dahlewitz (Germany); Freeman, C. [Rolls-Royce PLC, Derby (United Kingdom). Advanced Propulsion Systems; Day, I.J. [Cambridge Univ. (United Kingdom). Whittle Lab.

    1998-01-01

    During the development of the BR710 jet engine, audible combustor instabilities (termed rumble) occurred. Amplitudes measured with test cell microphones were up to 130 dB at around 100 Hz. Disturbances of this amplitude are clearly undesirable, even if only present during start-up, and a research program was initiated to eliminate the problem. Presented here is the methodical and structured approach used to identify, understand, and remove the instability. Some reference is made to theory, which was used for guidance, but the focus of the work is on the research done to find the cause of the problem and to correct it. The investigation followed two separate, but parallel, paths--one looking in detail at individual components of the engine to identify possible involvement in the instability and the other looking at the pressure signals from various parts of a complete engine to help pinpoint the source of the disturbance. The main cause of the BR710 combustor rumble was found to be a self-excited aerodynamic instability arising from the design of the fuel injector head. In the end, minor modifications lead to spray pattern changes, which greatly reduced the combustor noise. As a result of this work, new recommendation are made for reducing the risk of combustion instabilities in jet engines.

  5. Investigation of engine jet/wing-tip vortex interference

    Energy Technology Data Exchange (ETDEWEB)

    Huppertz, G.; Fares, E.; Abstiens, R.; Schroder, W. [Aerodynamisches Institut, RWTH Aachen (Germany)

    2004-04-01

    The wing-tip vortex of a rectangular wing half-model with a model engine is studied experimentally and numerically. The airfoil has a supercritical BAC 3-11/RES/30/21 geometry with a chord length of c = 150 mm. The investigations include three different span-wise positions of the engine and two jet velocities with a constant free stream velocity of u{infinity}=27 m/s yielding Rec = 2.8 x 10{sup 5}. The numerical simulation is divided into two parts. First the flow around the airfoil is calculated. In a second step the data is taken as an input to calculate the wake downstream of the trailing edge. Experiments include 2C- and 3C-PIV-measurements for the velocity distribution of the jet and the wing-tip vortices. The experimental and numerical results show the significance of the stream-wise velocity component for the analysis of the jet/wing-tip vortex interaction. (author)

  6. Damage-Tolerant Fan Casings for Jet Engines

    Science.gov (United States)

    2006-01-01

    All turbofan engines work on the same principle. A large fan at the front of the engine draws air in. A portion of the air enters the compressor, but a greater portion passes on the outside of the engine this is called bypass air. The air that enters the compressor then passes through several stages of rotating fan blades that compress the air more, and then it passes into the combustor. In the combustor, fuel is injected into the airstream, and the fuel-air mixture is ignited. The hot gasses produced expand rapidly to the rear, and the engine reacts by moving forward. If there is a flaw in the system, such as an unexpected obstruction, the fan blade can break, spin off, and harm other engine components. Fan casings, therefore, need to be strong enough to contain errant blades and damage-tolerant to withstand the punishment of a loose blade-turned-projectile. NASA has spearheaded research into improving jet engine fan casings, ultimately discovering a cost-effective approach to manufacturing damage-tolerant fan cases that also boast significant weight reduction. In an aircraft, weight reduction translates directly into fuel burn savings, increased payload, and greater aircraft range. This technology increases safety and structural integrity; is an attractive, viable option for engine manufacturers, because of the low-cost manufacturing; and it is a practical alternative for customers, as it has the added cost saving benefits of the weight reduction.

  7. Physics of Acoustic Radiation from Jet Engine Inlets

    Science.gov (United States)

    Tam, Christopher K. W.; Parrish, Sarah A.; Envia, Edmane; Chien, Eugene W.

    2012-01-01

    Numerical simulations of acoustic radiation from a jet engine inlet are performed using advanced computational aeroacoustics (CAA) algorithms and high-quality numerical boundary treatments. As a model of modern commercial jet engine inlets, the inlet geometry of the NASA Source Diagnostic Test (SDT) is used. Fan noise consists of tones and broadband sound. This investigation considers the radiation of tones associated with upstream propagating duct modes. The primary objective is to identify the dominant physical processes that determine the directivity of the radiated sound. Two such processes have been identified. They are acoustic diffraction and refraction. Diffraction is the natural tendency for an acoustic wave to follow a curved solid surface as it propagates. Refraction is the turning of the direction of propagation of sound waves by mean flow gradients. Parametric studies on the changes in the directivity of radiated sound due to variations in forward flight Mach number and duct mode frequency, azimuthal mode number, and radial mode number are carried out. It is found there is a significant difference in directivity for the radiation of the same duct mode from an engine inlet when operating in static condition and in forward flight. It will be shown that the large change in directivity is the result of the combined effects of diffraction and refraction.

  8. Variable geometry inlet design for scram jet engine

    Science.gov (United States)

    Guinan, Daniel P. (Inventor); Drake, Alan (Inventor); Andreadis, Dean (Inventor); Beckel, Stephen A. (Inventor)

    2005-01-01

    The present invention relates to an improved variable geometry inlet for a scram jet engine having at least one combustor module. The variable geometry inlet comprises each combustor module having two sidewalls. Each of the sidewalls has a central portion with a thickness and a tapered profile forward of the central portion. The tapered profile terminates in a sharp leading edge. The variable geometry inlet further comprises each module having a lower wall and a movable cowl flap positioned forward of the lower wall. The movable cowl flap has a leading edge and the leading edges of the sidewalls intersect the leading edge of the cowl flap.

  9. A jet engine noise measurement and prediction tool.

    Science.gov (United States)

    Frendi, Abdelkader; Dorland, Wade D; Maung, Thein; Nesman, Tom; Wang, Ten-See

    2002-11-01

    In this paper, the authors describe an innovative jet engine noise measurement and prediction tool. The tool measures sound-pressure levels and frequency spectra in the far field. In addition, the tool provides predicted results while the measurements are being made. The predictions are based on an existing computational fluid dynamics database coupled to an empirical acoustic radiation model based on the far-field approximation to the Lighthill acoustic analogy. Preliminary tests of this acoustic measurement and prediction tool produced very encouraging results.

  10. Jet Engine Nozzle Exit Configurations and Associated Systems and Methods

    Science.gov (United States)

    Mengle, Vinod G. (Inventor)

    2013-01-01

    Nozzle exit configurations and associated systems and methods are disclosed. An aircraft system in accordance with one embodiment includes a jet engine exhaust nozzle having an internal flow surface and an exit aperture, with the exit aperture having a perimeter that includes multiple projections extending in an aft direction. Aft portions of individual neighboring projections are spaced apart from each other by a gap, and a geometric feature of the multiple can change in a monotonic manner along at least a portion of the perimeter.

  11. Mixed exhaust flow supersonic jet engine and method

    Energy Technology Data Exchange (ETDEWEB)

    Klees, G.W.

    1993-06-08

    A method of operating a supersonic jet engine installation is described comprising (a) providing an engine having a variable area air inlet means and an outlet to discharge engine exhaust; (b) providing a secondary air passageway means; (c) receiving ambient air in the air inlet means and providing the ambient air as primary air to the engine inlet and secondary air to the secondary air passageway means; (d) providing a mixing section having an inlet portion and an exit portion, utilizing the mixing section in directing the exhaust from the engine to primary convergent/divergent exit passageway segments, where the exhaust is discharged at supersonic velocity as primary flow components, and directing secondary air flow from the secondary air passageway means to secondary exit passageway segments which are interspersed with the primary segments and from which the secondary air is discharged at subsonic velocity as secondary flow components; and (e) providing an exhaust section to receive the primary and secondary flow components in a mixing region and causing the primary and secondary flow components to mix to create a supersonic mixed flow, the exhaust section having a variable area final nozzle through which the mixed flow is discharged.

  12. Condensation in jet engine intake ducts during stationary operation

    Energy Technology Data Exchange (ETDEWEB)

    Young, J.B. [Univ. of Cambridge (United Kingdom). Whittle Lab.

    1995-04-01

    The paper describes on analysis of the condensation of moist air in very long intake ducts of jet engines during stationary operation. Problems arising from such condensation include fan over speed and increased stagnation pressure loss in the intake duct. The analysis demonstrates that, for moderate values of relative humidity, homogeneous condensation will occur in an outer annulus adjacent to the intake cowling if the local flow Mach number attains values of about 1.0. In the central region of the intake duct, where design Mach numbers of 0.8 may be attained, homogeneous condensation is unlikely to occur except, possibly, when the relative humidity is close to 100 percent and the ambient temperature very high. However, if the intake duct is very long, significant heterogeneous condensation on foreign particles present in the atmosphere is possible. The concentration of foreign nuclei required for this type of condensation is comparable to the likely levels of contamination at many industrial test sites. The effects of condensation on engine test results are twofold. First, condensation is a thermodynamically irreversible process and results in an increase of entropy and hence loss of total pressure in the intake duct. Uncorrected measurements using Pitot probes may not record this loss correctly. Second, the mass and energy transfer between the phases during the condensation process has a tendency to accelerate the flow approaching the engine, an effect that may be counteracted by a reduction in mass flow rate in order to maintain the static pressure constant. These conclusions are in agreement with experimental results obtained on-site during the testing of a jet engine fitted with a very long intake duct.

  13. Visualizations of Gas fuel Jet and Combustion Flame on Hydrogen Rotary Engine

    OpenAIRE

    田端, 道彦; 香川, 良二

    2011-01-01

    [Abstract] In this paper, it is a purpose to obtain basic information of a hydrogen jet and combustion flame characteristics of the hydrogen rotary engine. The jet characteristics of the hydrogen gas injector were measured by using the high-speed shadowgraph method. As the result, the jet penetration of the low density gas was weak. The mixing of the direction of the jet axis was disturbed for the low jet pressure. Next, the combustion flame propagation of the hydrogen rotary engine was visua...

  14. Optical technology applied to jet engine; Jet engine seigyo eno hikari gijutsu no tekiyo

    Energy Technology Data Exchange (ETDEWEB)

    Nakajima, T.; Ebina, K.; Endo, M. [Ishikawajima-Harima Heavy Industries Co. Ltd., Tokyo (Japan)

    1997-09-01

    Pyrometer that can be mounted on an aircraft engine is developed for measuring engine turbine blade temperatures. Energy radiated from the blade surface is collected by a lens and then forwarded to a photoelectric conversion photodiode through a heat-resistant optical fiber. A cleaning/purging mechanism is provided in case the lens collects dirt that will attenuate the signal for the indication of a temperature that is lower than the true temperature (in a cold shift phenomenon). The pyrometer is tested on an engine, when a measurement accuracy of {+-}10degC is attained without cold shift taking place. It responds to changes more swiftly than conventional types, which justifies its application to the control of engines. Since it works effectively to connect a bunch of optical fibers, rather than conventional electric wires, to the printed circuit board for guiding optical signals to a printed circuit board in a digital control unit, an optical backplane structure is developed. This structure is designed to be an optical waveguide type which can incorporate into itself some mechanisms of synthesizer, optical waveguide coupler, and light filter, in case of need for handling multiple transmission. The pyrometer is tested on an aircraft engine in operation at high and low temperatures, and demonstrates satisfying light-receiving and light-emitting properties. 4 refs., 10 figs.

  15. Applications of active adaptive noise control to jet engines

    Science.gov (United States)

    Shoureshi, Rahmat; Brackney, Larry

    1993-01-01

    During phase 2 research on the application of active noise control to jet engines, the development of multiple-input/multiple-output (MIMO) active adaptive noise control algorithms and acoustic/controls models for turbofan engines were considered. Specific goals for this research phase included: (1) implementation of a MIMO adaptive minimum variance active noise controller; and (2) turbofan engine model development. A minimum variance control law for adaptive active noise control has been developed, simulated, and implemented for single-input/single-output (SISO) systems. Since acoustic systems tend to be distributed, multiple sensors, and actuators are more appropriate. As such, the SISO minimum variance controller was extended to the MIMO case. Simulation and experimental results are presented. A state-space model of a simplified gas turbine engine is developed using the bond graph technique. The model retains important system behavior, yet is of low enough order to be useful for controller design. Expansion of the model to include multiple stages and spools is also discussed.

  16. On the Installation of Jet Engine Nacelles on a Wing Fourth Partial Report: Pressure-Distribution Measurements on a Sweptback Wing with Jet Engine Nacelle

    Science.gov (United States)

    Buschner, R.

    1949-01-01

    The present report, which deals with pressure-distribution measurements made on a sweptback wing with a jet engine nacelle, is similar to a report on pressure-distribution measurements on a rectangular wing with a jet engine nacelle (second partial report). Here, in investigations preliminary to high-speed measurements, as in the second partial report, useful arrangements and fillet designs have been discovered.

  17. Jet aircraft engine exhaust emissions database development: Year 1990 and 2015 scenarios

    Science.gov (United States)

    Landau, Z. Harry; Metwally, Munir; Vanalstyne, Richard; Ward, Clay A.

    1994-01-01

    Studies relating to environmental emissions associated with the High Speed Civil Transport (HSCT) military jet and charter jet aircraft were conducted by McDonnell Douglas Aerospace Transport Aircraft. The report includes engine emission results for baseline 1990 charter and military scenario and the projected jet engine emissions results for a 2015 scenario for a Mach 1.6 HSCT charter and military fleet. Discussions of the methodology used in formulating these databases are provided.

  18. Acoustic Characterization of Compact Jet Engine Simulator Units

    Science.gov (United States)

    Doty, Michael J.; Haskin, Henry H.

    2013-01-01

    Two dual-stream, heated jet, Compact Jet Engine Simulator (CJES) units are designed for wind tunnel acoustic experiments involving a Hybrid Wing Body (HWB) vehicle. The newly fabricated CJES units are characterized with a series of acoustic and flowfield investigations to ensure successful operation with minimal rig noise. To limit simulator size, consistent with a 5.8% HWB model, the CJES units adapt Ultra Compact Combustor (UCC) technology developed at the Air Force Research Laboratory. Stable and controllable operation of the combustor is demonstrated using passive swirl air injection and backpressuring of the combustion chamber. Combustion instability tones are eliminated using nonuniform flow conditioners in conjunction with upstream screens. Through proper flow conditioning, rig noise is reduced by more than 20 dB over a broad spectral range, but it is not completely eliminated at high frequencies. The low-noise chevron nozzle concept designed for the HWB test shows expected acoustic benefits when installed on the CJES unit, and consistency between CJES units is shown to be within 0.5 dB OASPL.

  19. Real-time measurements of jet aircraft engine exhaust.

    Science.gov (United States)

    Rogers, Fred; Arnott, Pat; Zielinska, Barbara; Sagebiel, John; Kelly, Kerry E; Wagner, David; Lighty, JoAnn S; Sarofim, Adel F

    2005-05-01

    Particulate-phase exhaust properties from two different types of ground-based jet aircraft engines--high-thrust and turboshaft--were studied with real-time instruments on a portable pallet and additional time-integrated sampling devices. The real-time instruments successfully characterized rapidly changing particulate mass, light absorption, and polycyclic aromatic hydrocarbon (PAH) content. The integrated measurements included particulate-size distributions, PAH, and carbon concentrations for an entire test run (i.e., "run-integrated" measurements). In all cases, the particle-size distributions showed single modes peaking at 20-40nm diameter. Measurements of exhaust from high-thrust F404 engines showed relatively low-light absorption compared with exhaust from a turboshaft engine. Particulate-phase PAH measurements generally varied in phase with both net particulate mass and with light-absorbing particulate concentrations. Unexplained response behavior sometimes occurred with the real-time PAH analyzer, although on average the real-time and integrated PAH methods agreed within the same order of magnitude found in earlier investigations.

  20. Production laser hardfacing of jet engine turbine blades

    Science.gov (United States)

    Duhamel, R. F.; Banas, C. M.; Kosenski, R. L.

    1986-01-01

    A high wear point exists at the notch between adjacent blades forming the outer shroud of a jet engine turbine stage. This notch is commonly hardfaced to reduce wear and improve turbine blade endurance. Until recently, the blades were manually hardfaced by the gas tungsten arc process. A laser hardfacing process was developed for this application which has increased production rates and reduced rework requirements. The laser's precise energy control, inherent repeatability, and ability to be automated are the principal reasons for these process improvements. Laser hardfacing fundamentals and process development are described. Production equipment characteristics are reviewed and unique features of the process are identified. Finally, the results of several years of production hardfacing experiences are discussed.

  1. Surface treatment by propane operated static jet engine

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    2003-03-01

    Based on the principle of the jet engine, by projecting abrasive materials in hot gas at supersonic speed, 'thermo-blasting' is an industrial solution for surface treatment which combines propane, innovation and environmental protection. From the very outset, these three reasons incited Primagaz to take part in the perfection and development of the system designed by Thermo-Blast International SA. This young company from Pau (Southern France) which also validated its design with Turbomeca and the ENSAM in Paris, is currently enjoying a growing reputation at international level. In order to remain the world leader in its field and retain its technological advance, Thermo-Blast continues to refine its process with the support of Primagaz and D.B. Consultants with regard to optimising gas combustion techniques. (author)

  2. Shape memory alloy actuated adaptive exhaust nozzle for jet engine

    Science.gov (United States)

    Song, Gangbing (Inventor); Ma, Ning (Inventor)

    2009-01-01

    The proposed adaptive exhaust nozzle features an innovative use of the shape memory alloy (SMA) actuators for actively control of the opening area of the exhaust nozzle for jet engines. The SMA actuators remotely control the opening area of the exhaust nozzle through a set of mechanism. An important advantage of using SMA actuators is the reduction of weight of the actuator system for variable area exhaust nozzle. Another advantage is that the SMA actuator can be activated using the heat from the exhaust and eliminate the need of other energy source. A prototype has been designed and fabricated. The functionality of the proposed SMA actuated adaptive exhaust nozzle is verified in the open-loop tests.

  3. Jet engine performance enhancement through use of a wave-rotor topping cycle

    Science.gov (United States)

    Wilson, Jack; Paxson, Daniel E.

    1993-01-01

    A simple model is used to calculate the thermal efficiency and specific power of simple jet engines and jet engines with a wave-rotor topping cycle. The performance of the wave rotor is based on measurements from a previous experiment. Applied to the case of an aircraft flying at Mach 0.8, the calculations show that an engine with a wave rotor topping cycle may have gains in thermal efficiency of approximately 1 to 2 percent and gains in specific power of approximately 10 to 16 percent over a simple jet engine with the same overall compression ratio. Even greater gains are possible if the wave rotor's performance can be improved.

  4. Free-jet Tests of a 1.1-inch-diameter Supersonic Ram-jet Engine

    Science.gov (United States)

    Judd, Joseph H; Trout, Otto F , Jr

    1957-01-01

    Results are presented of free-jet tests of a 1.1-inch-diameter hydrogen-burning ram-jet engine over a Mach number range from 1.42 to 2.28 and a Reynolds number range from 6.01 times 10 to the 6th power to 15.78 times 10 to the 6th power. Tests demonstrated the reliability and wide operating range of the engine and showed its suitability for installation on wind-tunnel models of airplane and missile configurations. A comparison of engine operation with combustion-chamber lengths of 3.33 and 1.51 engine diameters was made at a Mach number of 2.06. A maximum test thrust coefficient of 0.905 was obtained at fuel-air ratio of 0.034 and a Mach number of 2.06 for the engine with the 3.33-diameter combustion chamber.

  5. Meteorological Conditions Causing Jet-Engine Poweloss Events: Current Understanding

    Science.gov (United States)

    Strapp, J. W.; Ratvasky, T. P.

    2009-09-01

    The aviation industry is currently investigating a regular occurrence of jet engine-powerloss events which have now been attributed to the ingestion of atmospheric ice particles, usually in the vicinity of deep convection. There is a limited amount of information on the cloud microphysical properties near the cores of deep convection due to the potential hazards of flying in these areas, and due to the fact that it is a very challenging environment for current instrumentation. Most of the information that has been used to deduce the details of the conditions that cause engine powerloss has been extracted from the event-aircraft flight data recorders, pilot interviews, ground radar and satellite, a series of flight test programs in the 1950s and again in the 1990s, and the most recently available limited data from the cloud physics community. These have led to the conclusion that engine events occur due to flight through high mass concentrations of ice particles, probably with ice water contents (IWCs) in excess of 2 grams per cubic meter, and perhaps as high as 8. The limited microphysical data available has been used to suggest a median mass diameter of the ice particles of ~200 microns, with some evidence that it may be as low as 40 microns. These small particle sizes in the presence of high mass concentration is consistent with the lack of radar echoes > 20 dBZ observed on the pilot's radar, a consistent observation during engine events. The Engine Harmonization Working Group, an industry/regulator/government committee investigating engine powerloss, has concluded that the level of understanding of the properties of these clouds is inadequate to provide guidance to industry for engine design and testing. In order to address this issue, NASA and Environment Canada are planning to instrument an aircraft to make measurements in high IWC regions of tropical monsoon and continental convection. There is also a significant effort to upgrade and develop new

  6. The laboratory test rig with miniature jet engine to research aviation fuels combustion process

    OpenAIRE

    Gawron Bartosz; Białecki Tomasz

    2015-01-01

    This article presents laboratory test rig with a miniature turbojet engine (MiniJETRig – Miniature Jet Engine Test Rig), that was built in the Air Force Institute of Technology. The test rig has been developed for research and development works aimed at modelling and investigating processes and phenomena occurring in full scale jet engines. In the article construction of a test rig is described, with a brief discussion on the functionality of each of its main components. Additionally examples...

  7. Hyper-accreting black hole as GRB central engine. I: Baryon loading in GRB jets

    CERN Document Server

    Lei, Wei-Hua; Liang, En-Wei

    2012-01-01

    A hyper-accreting stellar-mass black hole has been long speculated as the best candidate of central engine of gamma-ray bursts (GRBs). Recent rich observations of GRBs by space missions such as Swift and Fermi pose new constraints on GRB central engine models. In this paper, we study the baryon loading processes of a GRB jet launched from a black hole central engine. We consider a relativistic jet powered by $\

  8. Engine jet entrainment in the near field of an aircraft

    Energy Technology Data Exchange (ETDEWEB)

    Garnier, F.; Jacquin, L.; Laverdant, A. [Office National d`Etudes et de Recherches Aerospatiales (ONERA), 92 - Chatillon (France)

    1997-12-31

    A simplified approach has been applied to analyse the mixing and entrainment processes of the engine exhaust through their interaction with the vortex wake of an aircraft. These investigations are focused on the near filed, extending from exit nozzle to the beginning of the vortex phase (i.e. to about twenty seconds after the wake is generated). This study is performed using an integral model and a numerical simulation for a two-engine large civil aircraft. The properties of the wing-tip vortices on the calculation of the dilution ratio (defined as a tracer concentration) have been shown. The mixing process is also affected by the buoyancy effect, but only after the jet regime, when the trapping in the vortex core has occurred. Qualitative comparison with contrail photography shows similar features. Finally the distortion and stretching of the plume streamlines inside the vortices can be observed, and the role of the descent of the vortices on the maximum tracer concentration has been discussed. (author) 19 refs.

  9. Investigation at Mach Numbers 2.98 and 2.18 of Axially Symmetric Free-jet Diffusion with a Ram-jet Engine

    Science.gov (United States)

    Hunczak, Henry R

    1952-01-01

    An investigation was conducted to determine the effectiveness of a free-jet diffuser in reducing the over-all pressure ratios required to operate a free jet with a large air-breathing engine as a test vehicle. Efficient operation of the free jet was determined with and without the considerations required for producing suitable engine-inlet flow conditions. A minimum operating pressure ration of 5.5 was attained with a ratio of nozzle-exit to engine-inlet area of 1.85. Operation of the free jet with unstable engine-inlet flow (buzz) is also included.

  10. Use of cross-correlation measurements to investigate noise generating regions of a real jet engine and a model jet

    Science.gov (United States)

    Meecham, W. C.; Hurdle, P. M.

    1974-01-01

    Cross-correlations are reported of the jet static pressure fluctuations (as measured with a B and K microphone fitted with a nose cone), with the far-field radiated sound pressure. These measurements were made for various probe positions and a large number of far-field positions (at various angles). In addition, the tests were run for a number of different jet exit velocities. The measured, normalized cross-correlation functions vary between 0.004 and 0.155. These values depend upon the angular position of the far-field microphone, the jet exit Mach number, and the position of the probe. In addition, the cross-correlation technique was employed to study the symmetry of the far-field radiated sound about the jet axis. Third-octave analyses of both the probe signal and the far-field radiated sound were made. This is the first time correlation measurements have been made on a jet engine. In addition, a report is given on an extensive noise survey of a model jet. The correlations are related to sound source functions and jet source regions are discussed.

  11. Laser drilling of thermal barrier coated jet-engine components

    Science.gov (United States)

    Sezer, H. K.

    Aero engine hot end components are often covered with ceramic Thermal Barrier Coatings (TBCs). Laser drilling in the TBC coated components can be a source of service life TBC degradation and spallation. The present study aims to understand the mechanisms of TBC delamination and develop techniques to drill holes without damaging the TBC, Nimonic 263 workpieces coated with TBC are used in the experiments. Microwave non-destructive testing (NDT) is employed to monitor the integrity of the coating /substrate interfaces of the post-laser drilled materials. A numerical modelling technique is used to investigate the role of melt ejection on TBC delamination. The model accounts for the vapour and the assist gas flow effects in the process. Broadly, melt ejection induced mechanical stresses for the TBC coating / bond coating and thermal effects for the bond coating / substrate interfaces are found the key delamination mechanisms. Experiments are carried out to validate the findings from the model. Various techniques that enable laser drilling without damaging the TBC are demonstrated. Twin jet assisted acute angle laser drilling is one successful technique that has been analysed using the melt ejection simulation. Optimisation of the twin jet assisted acute angle laser drilling process parameters is carried out using Design of Experiments (DoE) and statistical modelling approaches. Finally, an industrial case study to develop a high speed, high quality laser drilling system for combustor cans is described. Holes are drilled by percussion and trepan drilling in TBC coated and uncoated Haynes 230 workpieces. The production rate of percussion drilling is significantly higher than the trepan drilling, however metallurgical hole quality and reproducibility is poor. A number of process parameters are investigated to improve these characteristics. Gas type and gas pressure effects on various characteristics of the inclined laser drilled holes are investigated through theoretical

  12. Effect of Compressibility on Contrail Ice Particle Growth in an Engine Jet

    Science.gov (United States)

    Garnier, François; Maglaras, Ephi; Morency, François; Vancassel, Xavier

    2014-06-01

    In order to understand the formation process of condensation trails (contrails), the flow in the near field of an aircraft engine jet is studied by using the three-dimensional Large Eddy Simulation technique. The configuration consists of a hot round jet laden with soot particles. The particles are tracked using the Lagrangian approach, and their growth is calculated by a microphysics water vapour deposition model. A series of simulations are performed at a realistic Reynolds number (Re = 3.2 · 106) for two different jet Mach numbers: quasi-incompressible jet flow (M = 0.2) and compressible jet flow (M = 1). Whatever the Mach number used the ice crystals first appear at the edges of the jet where the hot and moist flow mixes with the cold and dry ambient air. Both the thermal transfers and the mass coupling, which are more significant for the quasi-incompressible jet flow, control the growth process.

  13. Manufacturing technology for advanced jet engines; Jisedai jetto engine no seizo gijutsu

    Energy Technology Data Exchange (ETDEWEB)

    Hirakawa, H. [Kawasaki Heavy Industries Ltd., Kobe (Japan)

    1997-04-05

    A part of the latest production technologies for aircraft jet engines is introduced. Outline of the turbofan engine, turbo-prop engine, and turbo-shaft engine are given. Every one of them employs a gas turbine engine comprising a compressor, combustor, and a turbine as the output generator. Increase in the turbine inlet temperature is effective for making the gas turbine engine more efficient. The development tread of heat resisting materials for realizing higher temperature is shown. The current status and future aspect of the manufacturing technology is discussed for each main component of the engine. Technological development for decreasing weight is important because the weight of the fan member increases when the fan diameter is increased to increase the bypass ratio. FRP is adopted for the blades and casing to decrease the weight of the compressor, and studies have been made on fiber reinforced materials to reduce the weight of the disks. The outlines of the latest manufacturing technologies for the combustor and turbine are introduced. 2 refs., 9 figs.

  14. 78 FR 70076 - Large Scale Networking (LSN)-Joint Engineering Team (JET)

    Science.gov (United States)

    2013-11-22

    ... Large Scale Networking (LSN)--Joint Engineering Team (JET) AGENCY: The Networking and Information... and non-Federal participants with interest in high performance research networking and networking to support science applications. The JET reports to the Large Scale Networking (LSN) Coordinating Group...

  15. 77 FR 58415 - Large Scale Networking (LSN); Joint Engineering Team (JET)

    Science.gov (United States)

    2012-09-20

    ... Large Scale Networking (LSN); Joint Engineering Team (JET) AGENCY: The Networking and Information... agencies and non-Federal participants with interest in high performance research networking and networking to support science applications. The JET reports to the Large Scale Networking (LSN)...

  16. Analysis of the reverse jet influence on particle ingestion at the engine inlet

    Science.gov (United States)

    Krasheninnikov, S. Yu.; Pudovikov, D. E.

    2015-06-01

    The reverse mode of an operating near-ground jet engine is considered. The air flow and particle trajectories under the engine intake are calculated. On the base of numerical and theoretical analysis of the air flow and particle trajectories, some conclusions about reducing the probability of transportation of large particles to the engine are drawn.

  17. Numerical Simulation of Tangling in Jet Engine Turbines

    Science.gov (United States)

    Cendón, David A.; Erice, Borja; Gálvez, Francisco; Sánchez-Gálvez, Vicente

    2012-12-01

    The numerical analysis of certain safety related problems presents serious difficulties, since the large number of components present leads to huge finite element models that can only be solved by using large and expensive computers or by making rough approaches to the problem. Tangling, or clashing, in the turbine of a jet engine airplane is an example of such problems. This is caused by the crash and friction between rotor and stator blades in the turbine after an eventual shaft failure. When facing the study of an event through numerical modelling, the accurate simulation of this problem would require the engineer to model all the rotor and stator blades existing in the turbine stage, using a small element size in all pieces. Given that the number of stator and rotor blades is usually around 200, such simulations would require millions of elements. This work presents a new numerical methodology, specifically developed for the accurate modelling of the tangling problem that, depending on the turbine configuration, is able to reduce the number of nodes up to an order of magnitude without losing accuracy. The methodology, which benefits from the cyclic configuration of turbines, is successfully applied to the numerical analysis of a hypothetical tangling event in a turbine, providing valuable data such as the rotating velocity decrease of the turbine, the braking torque and the damage suffered by the blades. The methodology is somewhat general and can be applied to any problem in which damage caused by the interaction between a rotating and static piece is to be analysed.

  18. Automated Infrared Inspection Of Jet Engine Turbine Blades

    Science.gov (United States)

    Bantel, T.; Bowman, D.; Halase, J.; Kenue, S.; Krisher, R.; Sippel, T.

    1986-03-01

    The detection of blocked surface cooling holes in hollow jet engine turbine blades and vanes during either manufacture or overhaul can be crucial to the integrity and longevity of the parts when in service. A fully automated infrared inspection system is being established under a tri-service's Manufacturing Technology (ManTech) contract administered by the Air Force to inspect these surface cooling holes for blockages. The method consists of viewing the surface holes of the blade with a scanning infrared radiometer when heated air is flushed through the blade. As the airfoil heats up, the resultant infrared images are written directly into computer memory where image analysis is performed. The computer then makes a determination of whether or not the holes are open from the inner plenum to the exterior surface and ultimately makes an accept/reject decision based on previously programmed criteria. A semiautomatic version has already been implemented and is more cost effective and more reliable than the previous manual inspection methods.

  19. Jet Engine Fan Blade Containment Using an Alternate Geometry

    Science.gov (United States)

    Carney, K.S.; Pereira, J.M.; Revilock, D.M.; Matheny, P.

    2008-01-01

    With a goal of reducing jet engine weight, simulations of a fan blade containment system with an alternate geometry were tested and analyzed. A projectile simulating a fan blade was shot at two alternate geometry containment case configurations using a gas gun. The first configuration was a flat plate representing a standard case configuration. The second configuration was a flat plate with a radially convex curve section at the impact point. The curved surface was designed to force the blade to deform plastically, dissipating energy before the full impact of the blade is received by the plate. The curved case was able to tolerate a higher impact velocity before failure. The computational model was developed and correlated with the tests and a weight savings assessment was performed. For the particular test configuration used in this study the ballistic impact velocity of the curved plate was approximately 60 m/s (200 ft/s) greater than that of the flat plate. For the computational model to successfully duplicate the test, the very high strain rate behavior of the materials had to be incorporated.

  20. Development of semi-free jet test facility for supersonic engine; Choonsoku engine shiken shisetsu semi free jet shiken sochi no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Kato, T.; Taguchi, H.; Omi, J.; Sakamoto, K. [Ishikawajima-Harima Heavy Industries Co. Ltd., Tokyo (Japan)

    2000-01-01

    IHI has been developing the SETF (Supersonic Engine Test Facility) to aim at the research and development of engines for the next generation commercial supersonic transport in the NAL (National Aerospace Laboratory in Japan). The SETF will supply the functions to test the supersonic engine performance in high altitude flight condition and supersonic intake-engine matching. The semi-free jet test mode was adopted for the supersonic intake-engine matching test, but this test configuration has not been conducted previously in Japan and there were a large number of unknown factors. IHI has developed a sub-scale test model in cooperation with NAL to identify the test conditions and a start sequence of the semi-free jet test mode. In addition, the designs of facility component were optimized and verified by using the CFD (Computational Fluid Dynamics) method. (author)

  1. Rotor Dynamic Analysis of RM12 Jet Engine Rotor using ANSYS

    OpenAIRE

    Srikrishnanivas, Deepak

    2012-01-01

    Rotordynamics is a field under mechanics, mainly deals with the vibration of rotating structures. In recent days, the study about rotordynamics has gained more importance within Jet engine industries. The main reason is Jet engine consists of many rotating parts constitutes a complex dynamic system. While designing rotors of high speed turbo machineries, it is of prime importance to consider rotordynamics characteristics in to account. Considering these characteristics at the design phase may...

  2. Simulations of Ultrarelativistic Magnetodynamic Jets from Gamma-ray Burst Engines

    CERN Document Server

    Tchekhovskoy, Alexander; Narayan, Ramesh

    2008-01-01

    Gamma-ray bursts (GRBs) require an engine capable of driving a jet of plasma to ultrarelativistic bulk Lorentz factors of up to several hundred and into narrow opening angles of a few degrees. We test whether the popular magnetic-driving paradigm can generate the required Lorentz factors and opening angles by finding global axisymmetric stationary solutions of magnetically-dominated (electromagnetically pure) ultrarelativistic jets. Our global solutions are obtained via time-dependent ideal relativistic magnetodynamical numerical simulations that follow the jet from the central engine to beyond six orders of magnitude in radius. Our model is primarily motivated by the collapsar model, in which a jet is produced by a spinning black hole or neutron star and then propagates through a massive stellar envelope. However, the results can be applied to other GRB models and other systems with relativistic jets. We find that the size of (and pressures within) the presupernova progenitor star can determine the terminal ...

  3. Aircraft dual-shaft jet engine with indirect action fuel flow controller

    Science.gov (United States)

    Tudosie, Alexandru-Nicolae

    2017-06-01

    The paper deals with an aircraft single-jet engine's control system, based on a fuel flow controller. Considering the engine as controlled object and its thrust the most important operation effect, from the multitude of engine's parameters only its rotational speed n is measurable and proportional to its thrust, so engine's speed has become the most important controlled parameter. Engine's control system is based on fuel injection Qi dosage, while the output is engine's speed n. Based on embedded system's main parts' mathematical models, the author has described the system by its block diagram with transfer functions; furthermore, some Simulink-Matlab simulations are performed, concerning embedded system quality (its output parameters time behavior) and, meanwhile, some conclusions concerning engine's parameters mutual influences are revealed. Quantitative determinations are based on author's previous research results and contributions, as well as on existing models (taken from technical literature). The method can be extended for any multi-spool engine, single- or twin-jet.

  4. Study of Efficiency Control by Hybrid Jet Engine Parameters

    Directory of Open Access Journals (Sweden)

    S. F. Maksimov

    2015-01-01

    Full Text Available The paper analyzes main control aspects of thrust jet engines, which use fuel components in different states of aggregation (solid fuels - liquid oxidant, a solid oxidizer - liquid fuel. Following the analytical review of literature a conclusion has been drawn that it is technically and functionally complicated to provide a process of thrust control by changing the mass flow and the combustion rate of a solid fuel charge.The objective of this work is to give a theoretical prediction of how the thermal knife impacts on the local combustion rate.The paper presents a diagram of interaction between thermal knife and solid fuel. There are three modes, namely: pyrolysis, transition (from pyrolysis to cutting charge, and fuel cut. In the computational model generation it is assumed that the solid fuel combustion rate is not dependent on the combustion direction, and the temperature distribution along the length of the charge (in the direction perpendicular to the face obeys the Michelson dependence without considering a resistance of the heated layer at the surface of the combustion charge. The paper considers mechanical interaction of the thermal knife with the surface of charge. The Hertz formula describes the relationship between the pressing force, the penetration depth and the radius of thermal knife mark in the fuel.Numerical modeling methods and direct calculations allow us to obtain relationships to describe the changing local combustion rate under the action of the thermal knife on a solid fuel charge in its mechanical penetration, depending on the blade geometry, mechanical properties of charge and pressing force.

  5. Transpiring Cooling of a Scram-Jet Engine Combustion Chamber

    Science.gov (United States)

    Choi, Sang H.; Scotti, Stephen J.; Song, Kyo D.; Ries,Heidi

    1997-01-01

    The peak cold-wall heating rate generated in a combustion chamber of a scram-jet engine can exceed 2000 Btu/sq ft sec (approx. 2344 W/sq cm). Therefore, a very effective heat dissipation mechanism is required to sustain such a high heating load. This research focused on the transpiration cooling mechanism that appears to be a promising approach to remove a large amount of heat from the engine wall. The transpiration cooling mechanism has two aspects. First, initial computations suggest that there is a reduction, as much as 75%, in the heat flux incident on the combustion chamber wall due to the transpirant modifying the combustor boundary layer. Secondly, the heat reaching the combustor wall is removed from the structure in a very effective manner by the transpirant. It is the second of these two mechanisms that is investigated experimentally in the subject paper. A transpiration cooling experiment using a radiant heating method, that provided a heat flux as high as 200 Btu/sq ft sec ( approx. 234 W/sq cm) on the surface of a specimen, was performed. The experiment utilized an arc-lamp facility (60-kW radiant power output) to provide a uniform heat flux to a test specimen. For safety reasons, helium gas was used as the transpirant in the experiments. The specimens were 1.9-cm diameter sintered, powdered-stainless-steel tubes of various porosities and a 2.54cm square tube with perforated multi-layered walls. A 15-cm portion of each specimen was heated. The cooling effectivenes and efficiencies by transpiration for each specimen were obtained using the experimental results. During the testing, various test specimens displayed a choking phenomenon in which the transpirant flow was limited as the heat flux was increased. The paper includes a preliminary analysis of the transpiration cooling mechanism and a scaling conversion study that translates the results from helium tests into the case when a hydrogen medium is used.

  6. Analysis of Performance of Jet Engine from Characteristics of Components II : Interaction of Components as Determined from Engine Operation

    Science.gov (United States)

    Goldstein, Arthur W; Alpert, Sumner; Beede, William; Kovach, Karl

    1949-01-01

    In order to understand the operation and the interaction of jet-engine components during engine operation and to determine how component characteristics may be used to compute engine performance, a method to analyze and to estimate performance of such engines was devised and applied to the study of the characteristics of a research turbojet engine built for this investigation. An attempt was made to correlate turbine performance obtained from engine experiments with that obtained by the simpler procedure of separately calibrating the turbine with cold air as a driving fluid in order to investigate the applicability of component calibration. The system of analysis was also applied to prediction of the engine and component performance with assumed modifications of the burner and bearing characteristics, to prediction of component and engine operation during engine acceleration, and to estimates of the performance of the engine and the components when the exhaust gas was used to drive a power turbine.

  7. Application of composite materials to turbofan engine fan exit guide vanes

    Science.gov (United States)

    Smith, G. T.

    1980-01-01

    A program was conducted by NASA with the JT9D engine manufacturer to develop a lightweight, cost effective, composite material fan exit guide vane design having satisfactory structural durability for commerical engine use. Based on the results of a previous company supported program, eight graphite/epoxy and graphite-glass/epoxy guide vane designs were evaluated and four were selected for fabrication and testing. Two commercial fabricators each fabricated 13 vanes. Fatigue tests were used to qualify the selected design configurations under nominally dry, 38 C (100 F) and fully wet and 60 C (140 F) environmental conditions. Cost estimates for a production rate of 1000 vanes per month ranged from 1.7 to 2.6 times the cost of an all aluminum vane. This cost is 50 to 80 percent less than the initial program target cost ratio which was 3 times the cost of an aluminum vane. Application to the JT9D commercial engine is projected to provide a weight savings of 236 N (53 lb) per engine.

  8. The laboratory test rig with miniature jet engine to research aviation fuels combustion process

    Directory of Open Access Journals (Sweden)

    Gawron Bartosz

    2015-12-01

    Full Text Available This article presents laboratory test rig with a miniature turbojet engine (MiniJETRig – Miniature Jet Engine Test Rig, that was built in the Air Force Institute of Technology. The test rig has been developed for research and development works aimed at modelling and investigating processes and phenomena occurring in full scale jet engines. In the article construction of a test rig is described, with a brief discussion on the functionality of each of its main components. Additionally examples of measurement results obtained during the realization of the initial tests have been included, presenting the capabilities of the test rig.

  9. Enhanced combustion by jet ignition in a turbocharged cryogenic port fuel injected hydrogen engine

    Energy Technology Data Exchange (ETDEWEB)

    Boretti, Alberto A.; Watson, Harry C. [Department of Mechanical Engineering, The University of Melbourne, 3010 Melbourne (Australia)

    2009-03-15

    The Hydrogen Assisted Jet Ignition (HAJI) is a physico-chemical combustion enhancement system developed at the University of Melbourne. Jet ignition can ignite ultra-lean air/fuel mixtures which are far beyond the stable ignition limit of a spark plug. Jet ignition may further enhance the combustion properties of hydrogen enabling the development of a diesel-like, almost throttle-less, control of load by quantity of fuel injected for higher thermal efficiencies all over the range of loads. The object of this paper is to show the benefits of jet ignition and present the latest results obtained on a four cylinder engine having the jet ignition coupled with cryogenic hydrogen injection and turbo charging. (author)

  10. On the wall jet from the ring crevice of an internal combustion engine

    Energy Technology Data Exchange (ETDEWEB)

    Cloutman, L.D. [Lawrence Livermore National Lab., CA (United States); Green, R.M. [Sandia National Labs., Livermore, CA (United States)

    1996-05-01

    Numerical simulations and experiments of the jetting of gases from the ring crevices of a laboratory engine shortly after exhaust valve opening showed an unanticipated radial flow of the crevice gases into the main combustion chamber. We report well-resolved numerical simulations of a wall jet that show that this radial motion is driven by vorticity generation in the wall boundary layer and at the corner of the piston crown.

  11. Modelling of the wall jet in a direct injection diesel engine

    Energy Technology Data Exchange (ETDEWEB)

    Desantes, J.M.; Lapuerta, M.; Salavert, J.M. (Universidad Politecnica de Valencia (ES). Dept. Maquinas y Motores Termicos)

    1992-01-01

    As a part of a phenomenological model, a method for simulating the wall/jet interaction in a direct injection diesel engine is proposed. The method is based on the application of the momentum conservation equation in the different directions in which the wall jet is spread, and takes into account both the interaction with the combustion chamber geometry and with swirl. It takes as initial conditions the results of calculating the free jet, which is divided into packages. The predictions provide good agreement with those by other researchers. (author).

  12. Pacer Comet 4: Automated Jet Engine Testing of a TF33-P100 Pratt & Whitney Engine

    Science.gov (United States)

    Mason, Rex Bolding

    Pacer Comet 4 found its life out of necessity to replace an obsolescent Pacer Comet 3 engine test system at Tinker AFB in Oklahoma City, OK. Pacer Comet 3 (PC3) was created and installed in the early 1980's to test jet engines from a wide range of planes. PC3 had several problems from a maintenance standpoint: contractors designed and installed the system but the contract did not include the OEM data package. Without drawings or design knowledge, fixing the smallest of problems could turn into a multi-day project. In addition to high cost, as the OEM companies of proprietary parts went out of business, it became impossible to find a replacement for a failed part. These issues set the framework for the Pacer Comet 4 (PC4) system. PC4 was created as an organic AF and Department of Defense collaboration to fix the issues with PC3. PC4 provides the customer with a complete data package including multiple drawing sets and data sheets for all parts used, as well as design files for all PCBs created in house. PC4 has a standard to use commercially available off the shelf parts (COTS). The reason for this is sustainability in maintenance. If a part is to fail, it should be able to be purchased from any manufacturer that meets the specs of the original product. No proprietary parts are used, except as directed by the engine's OEM. This thesis will focus on the design and installation of the on-frame data acquisition PC4 system for the Pratt & Whitney TF33-P100A-QEC engine that is currently in use on the E3 Sentry. This thesis will show efficiency improvements for maintenance sustainability (70% cabling reduction) as well as discuss performance improvements in both test and production environments.

  13. Twin Jet

    Science.gov (United States)

    Henderson, Brenda; Bozak, Rick

    2010-01-01

    Many subsonic and supersonic vehicles in the current fleet have multiple engines mounted near one another. Some future vehicle concepts may use innovative propulsion systems such as distributed propulsion which will result in multiple jets mounted in close proximity. Engine configurations with multiple jets have the ability to exploit jet-by-jet shielding which may significantly reduce noise. Jet-by-jet shielding is the ability of one jet to shield noise that is emitted by another jet. The sensitivity of jet-by-jet shielding to jet spacing and simulated flight stream Mach number are not well understood. The current experiment investigates the impact of jet spacing, jet operating condition, and flight stream Mach number on the noise radiated from subsonic and supersonic twin jets.

  14. Performance Evaluation of Particle Sampling Probes for Emission Measurements of Aircraft Jet Engines

    Science.gov (United States)

    Lee, Poshin; Chen, Da-Ren; Sanders, Terry (Technical Monitor)

    2001-01-01

    Considerable attention has been recently received on the impact of aircraft-produced aerosols upon the global climate. Sampling particles directly from jet engines has been performed by different research groups in the U.S. and Europe. However, a large variation has been observed among published data on the conversion efficiency and emission indexes of jet engines. The variation results surely from the differences in test engine types, engine operation conditions, and environmental conditions. The other factor that could result in the observed variation is the performance of sampling probes used. Unfortunately, it is often neglected in the jet engine community. Particle losses during the sampling, transport, and dilution processes are often not discussed/considered in literatures. To address this issue, we evaluated the performance of one sampling probe by challenging it with monodisperse particles. A significant performance difference was observed on the sampling probe evaluated under different temperature conditions. Thermophoretic effect, nonisokinetic sampling and turbulence loss contribute to the loss of particles in sampling probes. The results of this study show that particle loss can be dramatic if the sampling probe is not well designed. Further, the result allows ones to recover the actual size distributions emitted from jet engines.

  15. Black hole, jet, and disk the universal engine

    CERN Document Server

    Falcke, H

    1995-01-01

    In this paper I review the results of our ongoing project to investigate the coupling between accretion disk and radio jet in galactic nuclei and stellar mass black holes. We find a good correlation between the UV bump luminosity and the radio luminosities of AGN, which improves upon the usual [OIII]/radio correlations. Taking mass and energy conservation in the jet/disk system into account we can successfully model the correlation for radio-loud and radio-weak quasars. We find that jets are comparable in power to the accretion disk luminosity, and the difference between radio-loud and radio-weak may correspond to two natural stages of the relativistic electron distribution -- assuming that radio weak quasars have jets as well. The distribution of flat- and steep-spectrum sources is explained by bulk Lorentz factors gamma_j ~ 5-10. The absence of radio-loud quasars below a critical optical luminosity coincides with the FR I/FR II break and could be explained by a powerdependent, ``closing'' torus. This points...

  16. A study of flow and initial stage of water condensation in the exhaust jet of the aircraft turbofan engine

    OpenAIRE

    Lobanova, Maria,; Tsirkunov, Yury,

    2013-01-01

    The paper describes the results of numerical study of flow in the exhaust jet of turbofan engine CFM 56-3. Influence of computational domain decomposition, grid refinement and flow model on the jet flow field is discussed. Special attention is payed to simulation of nucleation and condensation processes in the exhaust jet. Growth of water clusters in the jet and cluster distribution in size are obtained.; International audience; The paper describes the results of numerical study of flow in th...

  17. On the design and structural analysis of jet engine fan blade structures

    Science.gov (United States)

    Amoo, Leye M.

    2013-07-01

    Progress in the design and structural analysis of commercial jet engine fan blades is reviewed and presented. This article is motivated by the key role fan blades play in the performance of advanced gas turbine jet engines. The fundamentals of the associated physics are emphasized. Recent developments and advancements have led to an increase and improvement in fan blade structural durability, stability and reliability. This article is intended as a high level review of the fan blade environment and current state of structural design to aid further research in developing new and innovative fan blade technologies.

  18. Vehicle implementation of a port injected M100 engine using plasma jet ignition and prompt EGR

    Energy Technology Data Exchange (ETDEWEB)

    Gardiner, D.P.; Mallory, R.W.; Rao, V.K.; Bardon, M.F. [Royal Military Coll. of Canada, Kingston, ON (Canada); Battista, V. [Department of Transport, Ottawa, ON (Canada)

    1994-10-01

    Overhead projection slides used at the 1994 Windsor Workshop on Alternative Fuels describing a port-injected engine using plasma jet ignition and prompt EGR were presented. Benefits of the engine were described, accompanied by technical information of its working concepts. Schematics and a comparison of the plasma jet ignition system with conventional spark plug ignition systems were outlined. Cold starting benefits and ignition hypothesis was summarized. Results of graphical analyses of cold-starting with high and normal cranking speeds were reviewed. 16 figs.

  19. The influence of jet engine noise on hearing of technical staff

    Directory of Open Access Journals (Sweden)

    Wiesław Konopka

    2014-10-01

    Full Text Available Background: Due to high sound pressure levels (SPLs, noise produced by jet planes may be harmful to hearing of people working in their proximity. The aim of this study was to assess the effects of exposure to jet engine noise on technical staff hearing. Material and Methods: The study comprised 60 men, aged 24–50 years, employed in army as technical staff and exposed to jet engine noise for 6–20 years. The control group were 50 non-noise exposed males, aged 25–51 years. Exposure to noise emitted by jet engines was evaluated. Pure-tone audiometry (PTA and distortion product otoacoustic emissions (DPOAE were recorded in both groups. Results: Jet engines emitted broadband noise with spectrum dominated by components in the frequency range 315–6300 Hz (1/3-octave bands. Maximum A-weighted SPL during tests reached values of approx. 120–130 dB. Consequently, engine-servicing personnel (even in the case of a single engine test was exposed to noise (at A-weighted daily noise exposure level above 95 dB exceeding permissible levels. Averaged audiometric hearing threshold levels of technical staff were higher (≤ 17 dB HL, p < 0.001 than in the control group. Similarly, the DPOAE amplitude was lower (≤ 17 dB SPL, p < 0.01 in the noise-exposed subjects compared to the non-exposed ones. Significant reduction of DPOAE levels was mainly noted for high frequencies (3–6 kHz. Conclusions: Despite the usage of hearing protection devices, both PTA and DPOAE consistently showed poorer hearing in engine-servicing personnel vs. control group. Med Pr 2014;65(5:583–592

  20. A NARROW SHORT-DURATION GRB JET FROM A WIDE CENTRAL ENGINE

    Energy Technology Data Exchange (ETDEWEB)

    Duffell, Paul C.; Quataert, Eliot [Astronomy Department and Theoretical Astrophysics Center, University of California, Berkeley, CA 94720 (United States); MacFadyen, Andrew I., E-mail: duffell@berkeley.edu [Center for Cosmology and Particle Physics, New York University (United States)

    2015-11-01

    We use two-dimensional relativistic hydrodynamic numerical calculations to show that highly collimated relativistic jets can be produced in neutron star merger models of short-duration gamma-ray bursts (GRBs) without the need for a highly directed engine or a large net magnetic flux. Even a hydrodynamic engine generating a very wide sustained outflow on small scales can, in principle, produce a highly collimated relativistic jet, facilitated by a dense surrounding medium that provides a cocoon surrounding the jet core. An oblate geometry to the surrounding gas significantly enhances the collimation process. Previous numerical simulations have shown that the merger of two neutron stars produces an oblate, expanding cloud of dynamical ejecta. We show that this gas can efficiently collimate the central engine power much like the surrounding star does in long-duration GRB models. For typical short-duration GRB central engine parameters, we find jets with opening angles of an order of 10° in which a large fraction of the total outflow power of the central engine resides in highly relativistic material. These results predict large differences in the opening angles of outflows from binary neutron star mergers versus neutron star–black hole mergers.

  1. A Narrow Short-duration GRB Jet from a Wide Central Engine

    Science.gov (United States)

    Duffell, Paul C.; Quataert, Eliot; MacFadyen, Andrew I.

    2015-11-01

    We use two-dimensional relativistic hydrodynamic numerical calculations to show that highly collimated relativistic jets can be produced in neutron star merger models of short-duration gamma-ray bursts (GRBs) without the need for a highly directed engine or a large net magnetic flux. Even a hydrodynamic engine generating a very wide sustained outflow on small scales can, in principle, produce a highly collimated relativistic jet, facilitated by a dense surrounding medium that provides a cocoon surrounding the jet core. An oblate geometry to the surrounding gas significantly enhances the collimation process. Previous numerical simulations have shown that the merger of two neutron stars produces an oblate, expanding cloud of dynamical ejecta. We show that this gas can efficiently collimate the central engine power much like the surrounding star does in long-duration GRB models. For typical short-duration GRB central engine parameters, we find jets with opening angles of an order of 10° in which a large fraction of the total outflow power of the central engine resides in highly relativistic material. These results predict large differences in the opening angles of outflows from binary neutron star mergers versus neutron star-black hole mergers.

  2. The politics of donating technological artifacts: techno-nationalism and the donations of the world’s first jet engines

    NARCIS (Netherlands)

    Giffard, Hermione

    2014-01-01

    The Smithsonian Institution’s aviation collection includes two early jet engines, both of which were given to the museum by foreign donors. The first, a prototype of Britain’s first jet engine, which flew during World War II, was donated by the British state in 1949. The second, a replica of Germany

  3. The politics of donating technological artifacts: techno-nationalism and the donations of the world’s first jet engines

    NARCIS (Netherlands)

    Giffard, Hermione

    2014-01-01

    The Smithsonian Institution’s aviation collection includes two early jet engines, both of which were given to the museum by foreign donors. The first, a prototype of Britain’s first jet engine, which flew during World War II, was donated by the British state in 1949. The second, a replica of

  4. The politics of donating technological artifacts: techno-nationalism and the donations of the world’s first jet engines

    NARCIS (Netherlands)

    Giffard, Hermione

    2014-01-01

    The Smithsonian Institution’s aviation collection includes two early jet engines, both of which were given to the museum by foreign donors. The first, a prototype of Britain’s first jet engine, which flew during World War II, was donated by the British state in 1949. The second, a replica of Germany

  5. The lean burn direct injection jet ignition gas engine

    Energy Technology Data Exchange (ETDEWEB)

    Boretti, Alberto A.; Watson, Harry C. [School of Science and Engineering, University of Ballarat, PO Box 663, Ballarat, Victoria 3353 (Australia)

    2009-09-15

    This paper presents a new in-cylinder mixture preparation and ignition system for various fuels including hydrogen, methane and propane. The system comprises a centrally located direct injection (DI) injector and a jet ignition (JI) device for combustion of the main chamber (MC) mixture. The fuel is injected in the MC with a new generation, fast actuating, high pressure, high flow rate DI injector capable of injection shaping and multiple events. This injector produces a bulk, lean stratified mixture. The JI system uses a second DI injector to inject a small amount of fuel in a small pre-chamber (PC). In the spark ignition (SI) version, a spark plug then ignites a slightly rich mixture. In the auto ignition version, a DI injector injects a small amount of higher pressure fuel in the small PC having a hot glow plug (GP) surface, and the fuel auto ignites in the hot air or when in contact with the hot surface. Either way the MC mixture is then bulk ignited through multiple jets of hot reacting gases. Bulk ignition of the lean, jet controlled, stratified MC mixture resulting from coupling DI with JI makes it possible to burn MC mixtures with fuel to air equivalence ratios reducing almost to zero for a throttle-less control of load diesel-like and high efficiencies over almost the full range of loads. (author)

  6. Study of heat transfer in CI engine using heat transfer correlation based on intake jet velocity

    Energy Technology Data Exchange (ETDEWEB)

    Sharief, A. [Sri Siddharhta Inst. of Technology, Tumkur, Karnataka (India); Samaga, B.S.; Shrinivas Rao, B.R. [Nitte Mahalinga Adyantaya Institute of Technology, Karkala, Karnataka (India); JAntonyc, A. [Sahyadri Inst. of Technology, Mangalore, Karnataka (India)

    2009-07-01

    A reliable heat transfer formulation is needed to simulate reciprocating combustion engines. In order to reduce heat loss and improve thermal efficiency, it is necessary to calculate the rate of heat transfer from the working fluid to the combustion chamber walls. The thermal stresses in the engine components must also be determined. In this study, the author calculated heat transfer coefficient in a diesel engine using a heat transfer correlation based on intake jet velocity instead of mean piston speed. Experiments were conducted in a diesel engine with natural aspiration of hot air at 150 to 300 degrees C. Peak temperature was 1100 degrees C at various loads. The convective heat transfer coefficient and radiative heat transfer coefficient component was also determined separately at various loads. This model based on intake jet velocity instead of mean piston speed was found to be more realistic when considering the influence of gas velocities on the thermal boundary layer thickness. 11 refs., 12 figs.

  7. Design, Fabrication, and Testing of an Auxiliary Cooling System for Jet Engines

    Science.gov (United States)

    Leamy, Kevin; Griffiths, Jim; Andersen, Paul; Joco, Fidel; Laski, Mark; Balser, Jeffrey (Technical Monitor)

    2001-01-01

    This report summarizes the technical effort of the Active Cooling for Enhanced Performance (ACEP) program sponsored by NASA. It covers the design, fabrication, and integrated systems testing of a jet engine auxiliary cooling system, or turbocooler, that significantly extends the use of conventional jet fuel as a heat sink. The turbocooler is designed to provide subcooled cooling air to the engine exhaust nozzle system or engine hot section. The turbocooler consists of three primary components: (1) a high-temperature air cycle machine driven by engine compressor discharge air, (2) a fuel/ air heat exchanger that transfers energy from the hot air to the fuel and uses a coating to mitigate fuel deposits, and (3) a high-temperature fuel injection system. The details of the turbocooler component designs and results of the integrated systems testing are documented. Industry Version-Data and information deemed subject to Limited Rights restrictions are omitted from this document.

  8. Optimal Replacement Policy of Jet Engine Modules from the Aircarrier's Point of View

    Directory of Open Access Journals (Sweden)

    Anita Domitrović

    2008-01-01

    Full Text Available A mathematical model for optimising preventive maintenanceof aircraft jet engine was developed by dynamic programming.Replacement planning for jet engine modules is regardedas a multistage decision process, while optimum modulereplacement is considered as a problem of equipment replacement.The goal of the optimal replacement policy of jet enginemodules is a defined series of decisions resulting in minimummaintenance costs. The model was programmed inC++ programming language and tested by using CFM56 jetengine data. The optimum maintenance strategy costs werecompared to costs of simpler experience-based maintenancestrategies. The results of the comparison j usti.JY further developmentand usage of the model in order to achieve significant costreduction for airline carriers.

  9. Episodic Jets as the Central Engine of Gamma-Ray Bursts

    CERN Document Server

    Yuan, Feng

    2012-01-01

    Most Gamma-ray bursts (GRBs) have erratic light curves, which demand that the GRB central engine launches an episodic outflow. Recent Fermi observations of some GRBs indicate a lack of the thermal photosphere component as predicted by the baryonic fireball model, which suggests a magnetic origin of GRBs. In view that powerful episodic jets have been observed along with continuous jets in other astrophysical black hole systems, here we propose an intrinsically episodic, magnetically-dominated jet model for GRB central engine. Accumulation and eruption of free magnetic energy in the corona of a differentially-rotating, turbulent accretion flow around a hyperaccreting black hole lead to ejections of episodic, magnetically dominated plasma blobs. These blobs are accelerated magnetically, collide with each other at large radii, trigger rapid magnetic reconnection and turbulence, efficient particle acceleration and radiation, and power the observed episodic prompt gamma-ray emission from GRBs.

  10. Episodic Jets as the Central Engine of Gamma-Ray Bursts

    Science.gov (United States)

    Yuan, Feng; Zhang, Bing

    2012-09-01

    Most gamma-ray bursts (GRBs) have erratic light curves, which demand that the GRB central engine launches an episodic outflow. Recent Fermi observations of some GRBs indicate a lack of the thermal photosphere component as predicted by the baryonic fireball model, which suggests a magnetic origin of GRBs. Given that powerful episodic jets have been observed along with continuous jets in other astrophysical black hole systems, here we propose an intrinsically episodic, magnetically dominated jet model for the GRB central engine. Accumulation and eruption of free magnetic energy in the corona of a differentially rotating, turbulent accretion flow around a hyperaccreting black hole lead to ejections of episodic, magnetically dominated plasma blobs. These blobs are accelerated magnetically, collide with each other at large radii, trigger rapid magnetic reconnection and turbulence, efficient particle acceleration, and radiation, and power the observed episodic prompt gamma-ray emission from GRBs.

  11. [Calculation and simulation on infrared radiation of hot jet from engine].

    Science.gov (United States)

    Li, Jian-Xun; Tong, Zhong-Xiang; Wang, Chao-Zhe; Tong, Qi; Li, He; Zhang, Zhi-Bo

    2013-01-01

    Spectral distribution of infrared radiation from plume by the method to calculate infrared radiance of the gaze direction in small sight field was calculated. Based on numerical value and form of radiative transfer equation, infrared radiant intensity of the gaze direction was calculated using the Malkmus statistical narrow-band model and CG approach. Flow field and mole fraction distribution were simulated using a FLUENT computational fluid dynamic (CFD) software. Infrared imaging simulation model of hot jet was established. The hot jet's infrared images of liquid rocket engine were generated. The results demonstrate that the method can detect well-resolved fine structure of flow field. And the model is also applicable to calculation and simulation on infrared radiation of hot jet from engine.

  12. Preliminary Report on Experimental Investigation of Engine Dynamics and Controls for a 48-inch Ram-jet Engine

    Science.gov (United States)

    Vasu, George; Hart, Clint E; Dunbar, William R

    1956-01-01

    Engine dynamics and controls data are presented for a ram-jet engine which was operated in a free-jet facility at a Mach number of 2.76 and altitudes from 68,000 to 82,000 feet. The predominant engine dynamic characteristics was dead time, with values ranging from 0.018 to 0.053 sec. The control systems were designed to hold a constant ratio of a diffuser static pressure to an inlet-cone reference static pressure. Response times and percent overshoot to fuel-flow disturbances that would have caused subcritical operation without control are included for a wide range of control settings. For all settings, the control response was fast enough (0.08 to 0.5 sec) to prevent subcritical operation.

  13. Environmental Assessment for Installation of a New Jet Engine Test Cell, Edwards Air Force Base, California

    Science.gov (United States)

    2012-09-01

    processes, the operation of internal combustion engines (e.g., auxiliary ground equipment, boilers, turbine engines, etc.) and adhesives /sealant...include jet and motor fuel, other types of petroleum products, paints, thinners, adhesives , cleaners, lead-acid batteries, hydraulic fluids and...of the recorded specimens consist of isolated fragments of tooth enamel or bone that are not securely dated. Irvingtonian fossil localities have

  14. Aerothermodynamic analysis of a Coanda/Refraction jet engine test facility.

    OpenAIRE

    Maraoui, André

    1988-01-01

    Approved for public release; distribution is unlimited A computer model of the Coanda Refraction Jet Engine Test Cell facility was developed using the PHOENICS computer code. The PIIOENICS code was utilized to determine the steady state aerothermal characteristics of the test cell during the testing of an E404 gas turbine engine with afterburner in operation. Computer generated aerothermodynamic field variables of pressure, velocity and temperature parameters were compared t...

  15. Integrated Computer Aided Planning and Manufacture of Advanced Technology Jet Engines

    Directory of Open Access Journals (Sweden)

    B. K. Subhas

    1987-10-01

    Full Text Available This paper highlights an attempt at evolving a computer aided manufacturing system on a personal computer. A case study of an advanced technology jet engine component is included to illustrate various outputs from the system. The proposed system could be an alternate solution to sophisticated and expensive CAD/CAM workstations.

  16. A Narrow Short-Duration GRB Jet from a Wide Central Engine

    CERN Document Server

    Duffell, Paul C; MacFadyen, Andrew I

    2015-01-01

    We use two-dimensional relativistic hydrodynamic numerical calculations to show that highly collimated relativistic jets can be produced in neutron star merger models of short-duration gamma ray bursts without the need for a highly directed engine or a large net magnetic flux. Even a hydrodynamic engine generating a very wide sustained outflow on small scales can in principle produce a highly collimated relativistic jet, facilitated by a dense surrounding medium which provides a cocoon surrounding the jet core. An oblate geometry to the surrounding gas significantly enhances the collimation process. Previous numerical simulations have shown that the merger of two neutron stars produces an oblate, expanding cloud of dynamical ejecta. We show that this gas can efficiently collimate the central engine power much as the surrounding star does in long-duration GRB models. For typical short-duration GRB central engine parameters, we find jets with opening angles of order 10 degrees in which a large fraction of the t...

  17. Loadings in thermal barrier coatings of jet engine turbine blades an experimental research and numerical modeling

    CERN Document Server

    Sadowski, Tomasz

    2016-01-01

    This book discusses complex loadings of turbine blades and protective layer Thermal Barrier Coating (TBC), under real working airplane jet conditions. They obey both multi-axial mechanical loading and sudden temperature variation during starting and landing of the airplanes. In particular, two types of blades are analyzed: stationary and rotating, which are widely applied in turbine engines produced by airplane factories.

  18. Volatile properties of jet engine combustor particles during the partemis campaign

    Energy Technology Data Exchange (ETDEWEB)

    Nyeki, S.; Gysel, M.; Weingartner, E.; Baltensperger, U.; Petzold, A. [Deutsche Luft- und Raumfahrt, Oberpfaffenhofen (Germany); Wilson, C.W.

    2002-03-01

    The influence of fuel sulphur content (FSC) on exhaust particle properties from a jet engine combustor test rig was investigated during the EC PartEmis project. Volatile properties were measured using a Volatility Tandem Differential Mobility Analyser (V-TDMA). Measurements indicated that particles with diameter d <30 nm were more volatile than larger particles. (author)

  19. Jet engine with electromagnetic field excitation of expendable solid-state material

    Science.gov (United States)

    Tsybin, O. Yu.; Makarov, S. B.; Ostapenko, O. N.

    2016-12-01

    Electromagnetic field action on a solid-state natural raw material is considered here in the context of producing a mechanical reactive momentum. We suggest the development of a jet engine that possesses fast control and low thrust based on desorption or sputtering of particles flow from a solid surface.

  20. Boundary conditions towards realistic simulation of jet engine noise

    Science.gov (United States)

    Dhamankar, Nitin S.

    Strict noise regulations at major airports and increasing environmental concerns have made prediction and attenuation of jet noise an active research topic. Large eddy simulation coupled with computational aeroacoustics has the potential to be a significant research tool for this problem. With the emergence of petascale computer clusters, it is now computationally feasible to include the nozzle geometry in jet noise simulations. In high Reynolds number experiments on jet noise, the turbulent boundary layer on the inner surface of the nozzle separates into a turbulent free shear layer. Inclusion of a nozzle with turbulent inlet conditions is necessary to simulate this phenomenon realistically. This will allow a reasonable comparison of numerically computed noise levels with the experimental results. Two viscous wall boundary conditions are implemented for modeling the nozzle walls. A characteristic-based approach is compared with a computationally cheaper, extrapolation-based formulation. In viscous flow over a circular cylinder under two different regimes, excellent agreement is observed between the results of the two approaches. The results agree reasonably well with reference experimental and numerical results. Both the boundary conditions are thus found to be appropriate, the extrapolation-based formulation having an edge with its low cost. This is followed with the crucial step of generation of a turbulent boundary layer inside the nozzle. A digital filter-based turbulent inflow condition, extended in a new way to non-uniform curvilinear grids is implemented to achieve this. A zero pressure gradient flat plate turbulent boundary layer is simulated at a high Reynolds number to show that the method is capable of producing sustained turbulence. The length of the adjustment region necessary for synthetic inlet turbulence to recover from modeling errors is estimated. A low Reynolds number jet simulation including a round nozzle geometry is performed and the method

  1. Jet engine applications for materials with nanometer-scale dimensions

    Energy Technology Data Exchange (ETDEWEB)

    Appleby, J.W. Jr.

    1995-10-01

    The performance of advanced military and commercial gas turbine engines is often linked to advances in materials technology. High performance gas turbine engines being developed require major material advances in strength, toughness, reduced density and improved temperature capability. The emerging technology of nanostructured materials has enormous potential for producing materials with significant improvements in these properties. Extraordinary properties demonstrated in the laboratory include material strengths approaching theoretical limit, ceramics that demonstrate ductility and toughness, and materials with ultra-high hardness. Nanostructured materials and coatings have the potential for meeting future gas turbine engine requirements for improved performance, reduced weight and lower fuel consumption.

  2. Jet engine applications for materials with nanometer-scale dimensions

    Science.gov (United States)

    Appleby, J. W., Jr.

    1995-01-01

    The performance of advanced military and commercial gas turbine engines is often linked to advances in materials technology. High performance gas turbine engines being developed require major material advances in strength, toughness, reduced density and improved temperature capability. The emerging technology of nanostructured materials has enormous potential for producing materials with significant improvements in these properties. Extraordinary properties demonstrated in the laboratory include material strengths approaching theoretical limit, ceramics that demonstrate ductility and toughness, and materials with ultra-high hardness. Nanostructured materials and coatings have the potential for meeting future gas turbine engine requirements for improved performance, reduced weight and lower fuel consumption.

  3. Direct E-jet printing of three-dimensional fibrous scaffold for tendon tissue engineering.

    Science.gov (United States)

    Wu, Yang; Wang, Zuyong; Ying Hsi Fuh, Jerry; San Wong, Yoke; Wang, Wilson; San Thian, Eng

    2017-04-01

    Tissue engineering (TE) offers a promising strategy to restore diseased tendon tissue. However, a suitable scaffold for tendon TE has not been achieved with current fabrication techniques. Herein, we report the development of a novel electrohydrodynamic jet printing (E-jetting) for engineering 3D tendon scaffold with high porosity and orientated micrometer-size fibers. The E-jetted scaffold comprised tubular multilayered micrometer-size fibrous bundles, with interconnected spacing and geometric anisotropy along the longitudinal direction of the scaffold. Fiber diameter, stacking pattern, and interfiber distance have been observed to affect the structural stability of the scaffold, of which the enhanced mechanical strength can be obtained for scaffolds with thick fibers as the supporting layer. Human tenocytes showed a significant increase in cellular metabolism on the E-jetted scaffolds as compared to that on conventional electrospun scaffolds (2.7-, 2.8-, and 3.1-fold increase for 150, 300, and 600 µm interfiber distance, respectively; p scaffolds provided structural support for human tenocytes to align with controlled orientation along the longitudinal direction of the scaffold, and promoted the expression of collagen type I. For the first time, E-jetting has been explored as a novel scaffolding approach for tendon TE, and offers a 3D fibrous scaffold to promote organized tissue reconstruction for potential tendon healing. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 616-627, 2017.

  4. Experimental Investigation on Space-dispersed Double-wall Jet Combustion System for DI Diesel Engine

    Institute of Scientific and Technical Information of China (English)

    郭鹏江; 高希彦

    2012-01-01

    A space-dispersed double-wall jet combustion system was developed by adopting the wall-guiding spray method and the stratification theory.The experimental test was carried out to optimize the structural parameters of the diesel-engine combustion system,including chamber structure,swirl ratio of cylinder head,included angle of jet orifice,number and diameter of jet orifice,fuel injection pressure and timing.The effect of double-wall jet combustion system on combustion and engine performance was tested to obtain the best performance indexes,and the double-wall jet combustion system was compared to the prototype.The results show that NOx is reduced from 712 PPm to 487 PPm at 2 100 r/min,and from 593 PPm to 369 PPm at 3 000 r/min,which are reduced by 31.6% and 37.7%,respectively.The smoke intensity was reduced form 3.67 BSU to 2.1 BSU,and the oil consumption was reduced from 240.5 g/(kW·h) to 225.4 g/(kW·h),which was decreased by 6.3% at low speed.The pressure in the cylinder was obviously reduced from 115 bar to 108 bar,which was reduced by 6%.

  5. Assessment of an anomaly detector for jet engine health monitoring

    OpenAIRE

    Sebastien Borguet; Olivier Léonard

    2011-01-01

    The goal of module performance analysis is to reliably assess the health of the main components of an aircraft engine. A predictive maintenance strategy can leverage this information to increase operability and safety as well as to reduce costs. Degradation undergone by an engine can be divided into gradual deterioration and accidental events. Kalman filters have proven very efficient at tracking progressive deterioration but are poor performers in the face of abrupt events. Adaptive estimati...

  6. Component-specific modeling. [jet engine hot section components

    Science.gov (United States)

    Mcknight, R. L.; Maffeo, R. J.; Tipton, M. T.; Weber, G.

    1992-01-01

    Accomplishments are described for a 3 year program to develop methodology for component-specific modeling of aircraft hot section components (turbine blades, turbine vanes, and burner liners). These accomplishments include: (1) engine thermodynamic and mission models, (2) geometry model generators, (3) remeshing, (4) specialty three-dimensional inelastic structural analysis, (5) computationally efficient solvers, (6) adaptive solution strategies, (7) engine performance parameters/component response variables decomposition and synthesis, (8) integrated software architecture and development, and (9) validation cases for software developed.

  7. Formation And Ingestion Of Vortices Into Jet Engines During Operation

    Science.gov (United States)

    Hua, Ho Wei; Jermy, Mark

    2009-01-01

    Vortices can be produced and ingested into the intake of a turbofan and turbojet aero engine during high power operation near solid surfaces. This can happen either on the runway during take-off or during engine test runs in a test cell. The vortex can throw debris into the intake or cause the compressor to stall causing significant damage to the engine and may require major overhaul. The ability to predict the onset of a vortex is therefore extremely valuable to the industry and could potentially save millions of dollars in overhaul costs. The factors that determines whether or not a vortex forms include engine thrust level, geometric factors such as the distance between the engine core and the ground and the size of the engine core, and flow conditions such as ambient vorticity and height of boundary layer. Computational fluid dynamic studies have been carried out by the authors to attempt to predict the effects that these factors have on the threshold of vortex formation. These works include the first reported studies of numerical predictions of the vortex formation threshold on both the runway or test cell scenarios and include factors that have not been previously studied either numerically or experimentally.

  8. Hyperaccreting Black Hole as Gamma-Ray Burst Central Engine. I. Baryon Loading in Gamma-Ray Burst Jets

    Science.gov (United States)

    Lei, Wei-Hua; Zhang, Bing; Liang, En-Wei

    2013-03-01

    A hyperaccreting stellar-mass black hole has been long speculated as the best candidate for the central engine of gamma-ray bursts (GRBs). Recent rich observations of GRBs by space missions such as Swift and Fermi pose new constraints on GRB central engine models. In this paper, we study the baryon-loading processes of a GRB jet launched from a black hole central engine. We consider a relativistic jet powered by \

  9. The new 1.8 I DI turbo-jet gasoline engine from Fiat Powertrain Technologies

    Energy Technology Data Exchange (ETDEWEB)

    Andriesse, Dirk; Comignaghi, Emilio; Lucignano, Gennaro; Oreggioni, Aldo; Quinto, Stefano; Sacco, Dario [Fiat Powertrain Technologies, Arese-Turin (Italy)

    2008-07-01

    The newly developed 1.8 ltr gasoline DI Turbo-Jet engine extends the gasoline product portfolio of Fiat Powertrain Technologies after the successful launch of the 1.4 ltr T-jet engine family in 2007. FPT retains the turbo downsizing concept the most efficient measure to meet the required reduction of CO2 emissions enhancing in the meantime the fun to drive characteristics of the gasoline engine, with the aim to equal at least those of DI turbo diesel units. The adoption of the turbocharger permits as well to differentiate the engines by tuning according to the brand requirements of the various Fiat Group car platforms. The common mechanical base is ideal to provide both the best thermodynamic efficiency and the cost advantages given by the production volumes. Thanks to the direct injection, the double continuously variable cam phasing and turbo charging the new 1.8 ltr DI Turbo-Jet engine develops high specific maximum torque and power values: the HP variant reaches nearly 200 Nm/l and 100 kW/l. The excellent low end torque and fast turbo response are obtained by newly developed advanced EMS scavenging strategies. The final result is highlighted by the 23.1 bar BMEP value at 1400 rpm for the Soft version which is the benchmark today for all gasoline turbocharged engines on the market. Emission levels meet the new Euro 5 standards with a large margin thanks to multiple injection and high pressure stratified charge start strategies even using a packaging friendly low volume close coupled catalytic system. To reach the stringent NVH requirements the engine is mechanically optimised by adopting a slightly over square bore/stroke ratio, a long conrod, a moderate rated engine speed and low alternating masses. Excellent results are obtained which equal those of competitor engines without the use of secondary order balancing shafts. (orig.)

  10. Primary atomization of liquid jets issuing from rocket engine coaxial injectors

    Science.gov (United States)

    Woodward, Roger D.

    1993-01-01

    The investigation of liquid jet breakup and spray development is critical to the understanding of combustion phenomena in liquid-propellant rocket engines. Much work has been done to characterize low-speed liquid jet breakup and dilute sprays, but atomizing jets and dense sprays have yielded few quantitative measurements due to their optical opacity. This work focuses on a characteristic of the primary breakup process of round liquid jets, namely the length of the intact liquid core. The specific application considered is that of shear-coaxial type rocket engine injectors. Real-time x-ray radiography, capable of imaging through the dense two-phase region surrounding the liquid core, has been used to make the measurements. Nitrogen and helium were employed as the fuel simulants while an x-ray absorbing potassium iodide aqueous solution was used as the liquid oxygen (LOX) simulant. The intact-liquid-core length data have been obtained and interpreted to illustrate the effects of chamber pressure (gas density), injected-gas and liquid velocities, and cavitation. The results clearly show that the effect of cavitation must be considered at low chamber pressures since it can be the dominant breakup mechanism. A correlation of intact core length in terms of gas-to-liquid density ratio, liquid jet Reynolds number, and Weber number is suggested. The gas-to-liquid density ratio appears to be the key parameter for aerodynamic shear breakup in this study. A small number of hot-fire, LOX/hydrogen tests were also conducted to attempt intact-LOX-core measurements under realistic conditions in a single-coaxial-element rocket engine. The tests were not successful in terms of measuring the intact core, but instantaneous imaging of LOX jets suggests that LOX jet breakup is qualitatively similar to that of cold-flow, propellant-simulant jets. The liquid oxygen jets survived in the hot-fire environment much longer than expected, and LOX was even visualized exiting the chamber nozzle

  11. An experimental investigation of reacting and nonreacting coaxial jet mixing in a laboratory rocket engine

    Science.gov (United States)

    Schumaker, Stephen Alexander

    Coaxial jets are commonly used as injectors in propulsion and combustion devices due to both the simplicity of their geometry and the rapid mixing they provide. In liquid rocket engines it is common to use coaxial jets in the context of airblast atomization. However, interest exists in developing rocket engines using a full flow staged combustion cycle. In such a configuration both propellants are injected in the gaseous phase. In addition, gaseous coaxial jets have been identified as an ideal test case for the validation of the next generation of injector modeling tools. For these reasons an understanding of the fundamental phenomena which govern mixing in gaseous coaxial jets and the effect of combustion on these phenomena in coaxial jet diffusion flames is needed. A study was performed to better understand the scaling of the stoichiometric mixing length in reacting and nonreacting coaxial jets with velocity ratios greater than one and density ratios less than one. A facility was developed that incorporates a single shear coaxial injector in a laboratory rocket engine capable of ten atmospheres. Optical access allows the use of flame luminosity and laser diagnostic techniques such as Planar Laser Induced Fluorescence (PLIF). Stoichiometric mixing lengths (LS), which are defined as the distance along the centerline where the stoichiometric condition occurs, were measured using PLIF. Acetone was seeded into the center jet to provide direct PLIF measurement of the average and instantaneous mixture fraction fields for a range of momentum flux ratios for the nonreacting cases. For the coaxial jet diffusion flames, LS was measured from OH radical contours. For nonreacting cases the use of a nondimensional momentum flux ratio was found to collapse the mixing length data. The flame lengths of coaxial jet diffusion flames were also found to scale with the momentum flux ratio but different scaling constants are required which depended on the chemistry of the reaction. The

  12. A new model of the central engine of GRB and the cosmic jets

    Science.gov (United States)

    Fiziev, P.; Staicova, D.

    Despite the volume of already existing observational data, current models still cannot explain completely the excessive energy output and the time variability of gamma-ray bursts(GRB). One of the reasons for this is the lack of a good model of the central engine of GRB. A major problem in the proposed models with a black hole (BH) in the center is that they don't explain the observed evidences of late time activity of the central engine. In this paper we are starting the search for a possible model of that central engine as a rotating compact body of still unknown nature. The formation of jets in the new model lies entirely on the fundamental Teukolsky Master Equation. We demonstrate that this general model can describe the formation of collimated GRB-jets of various forms. Some preliminary results are presented.

  13. A new model of the Central Engine of GRB and the Cosmic Jets

    CERN Document Server

    Fiziev, P P

    2009-01-01

    Despite all the already existing observational data, current models still cannot explain completely the excessive energy output and the time variability of GRB. One of the reasons for this is the lack of a good model of the central engine of GRB. A major problem in the proposed models with a black hole (BH) in the center is that they don't explain the observed evidences of late time activity of the central engine. In this paper we are starting the search for a possible model of that central engine as a rotating compact body of still unknown nature. The formation of jets in the new model lies entirely on the fundamental Teukolsky Master Equation. We demonstrate that this general model can describe the formation of collimated GRB-jets of various forms. Some preliminary results are presented.

  14. Hydraulic fluids and jet engine oil: pyrolysis and aircraft air quality.

    Science.gov (United States)

    van Netten, C; Leung, V

    2001-01-01

    Incidents of smoke in aircraft cabins often result from jet engine oil and/or hydraulic fluid that leaks into ventilation air, which can be subjected to temperatures that exceed 500 degrees C. Exposed flight-crew members have reported symptoms, including dizziness, nausea, disorientation, blurred vision, and tingling in the legs and arms. In this study, the authors investigated pyrolysis products of one jet engine oil and two hydraulic fluids at 525 degrees C. Engine oil was an important source of carbon monoxide. Volatile agents and organophosphate constituents were released from all the agents tested; however, the neurotoxin trimethyl propane phosphate was not found. The authors hypothesized that localized condensation of pyrolysis products in ventilation ducts, followed by mobilization when cabin heat demand was high, accounted for mid-flight incidents. The authors recommended that carbon monoxide data be logged continuously to capture levels during future incidents.

  15. Three-dimensional Simulations of Long Duration Gamma-ray Burst Jets: Timescales from Variable Engines

    Science.gov (United States)

    López-Cámara, D.; Lazzati, Davide; Morsony, Brian J.

    2016-08-01

    Gamma-ray burst (GRB) light curves are characterized by marked variability, each showing unique properties. The origin of this variability, at least for a fraction of long GRBs, may be the result of an unsteady central engine. It is thus important to study the effects that an episodic central engine has on the jet propagation and, eventually, on the prompt emission within the collapsar scenario. Thus, in this study we follow the interaction of pulsed outflows with their progenitor stars with hydrodynamic numerical simulations in both two and three dimensions. We show that the propagation of unsteady jets is affected by the interaction with the progenitor material well after the break-out time, especially for jets with long quiescent times comparable to or larger than a second. We also show that this interaction can lead to an asymmetric behavior in which pulse durations and quiescent periods are systematically different. After the pulsed jets drill through the progenitor and the interstellar medium, we find that, on average, the quiescent epochs last longer than the pulses (even in simulations with symmetrical active and quiescent engine times). This could explain the asymmetry detected in the light curves of long quiescent time GRBs.

  16. Numerical modeling of a Jet Ignition Direct Injection (JIDI) LPG engine

    OpenAIRE

    albert boretti

    2016-01-01

    The paper presents indirectly validated simulations of the operation of a LPG engine fitted with Direct Injection (DI) and Jet Ignition (JI). It is demonstrated that the engine may have diesel like efficiencies and load control by quantity of fuel injected.  As the liquid propane quickly evaporates after injection in the main chamber, the main chamber mixture may be much closer to stoichiometry than a diesel for a better specific power at low engine speeds. This design also works at the high ...

  17. Assessment of an Anomaly Detector for Jet Engine Health Monitoring

    Directory of Open Access Journals (Sweden)

    Sebastien Borguet

    2011-01-01

    Full Text Available The goal of module performance analysis is to reliably assess the health of the main components of an aircraft engine. A predictive maintenance strategy can leverage this information to increase operability and safety as well as to reduce costs. Degradation undergone by an engine can be divided into gradual deterioration and accidental events. Kalman filters have proven very efficient at tracking progressive deterioration but are poor performers in the face of abrupt events. Adaptive estimation is considered as an appropriate solution to this deficiency. This paper reports the evaluation of the detection capability of an adaptive diagnosis tool on the basis of simulated scenarios that may be encountered during the operation of a commercial turbofan engine. The diagnosis tool combines a Kalman filter and a secondary system that monitors the residuals. This auxiliary component implements a generalised likelihood ratio test in order to detect abrupt events.

  18. Eye and respiratory irritants in jet engine exhaust.

    Science.gov (United States)

    Miyamoto, Y

    1986-11-01

    It has been noted that eye and respiratory irritation frequently occurred in the ground crews and pilots working on the field behind an aircraft with a low smoke combustor (LSC) engine. This study was attempted to analyze the exhaust sampled at about 50 m behind the LSC J79 engines at idle power setting by means of a high performance liquid chromatography (HPLC) technique. Nine kinds of lower aliphatic carbonyl compound (seven aldehydes and two ketones) were identified. The concentration of formaldehyde was the highest among them, showing the value above the threshold reported by previous investigators. Concentration of NOx was simultaneously measured by a gas detector tube in the same sample. The exhaust of a conventional J79 engine, which has rarely caused irritation, was also analyzed by the same technique and the results were compared. It was concluded that formaldehyde plays a major role in causing irritation.

  19. Laser pointing in the vicinity of jet engine plumes

    NARCIS (Netherlands)

    Schleijpen, H.M.A.

    2009-01-01

    Target tracking and laser-based pointing from airborne platforms can be degraded significantly by the propagation environment around an airborne platform including zones of severe turbulence generated by rotor downwash and engine exhausts. This is the topic of the EDA study group ERG 108.019 on "Las

  20. Laser pointing in the vicinity of jet engine plumes

    NARCIS (Netherlands)

    Schleijpen, H.M.A.

    2010-01-01

    Target tracking and laser-based pointing from airborne platforms can be degraded significantly by the propagation environment around an airborne platform including zones of severe turbulence generated by rotor downwash and engine exhausts. This is the topic of the EDA study group ERG 108.019 on “Las

  1. Primary VOC emissions from Commercial Aircraft Jet Engines

    Science.gov (United States)

    Kilic, Dogushan; Huang, Rujin; Slowik, Jay; Brem, Benjamin; Durdina, Lukas; Rindlisbacher, Theo; Baltensperger, Urs; Prevot, Andre

    2014-05-01

    Air traffic is growing continuously [1]. The increasing number of airplanes leads to an increase of aviation emissions giving rise to environmental concerns globally by high altitude emissions and, locally on air quality at the ground level [2]. The overall impact of aviation emissions on the environment is likely to increase when the growing air transportation trend [2] is considered. The Aviation Particle Regulatory Instrumentation Demonstration Experiment (APRIDE)-5 campaign took place at Zurich Airport in 2013. In this campaign, aircraft exhaust is sampled during engine acceptance tests after engine overhaul at the facilities of SR Technics. Direct sampling from the engine core is made possible due to the unique fixed installation of a retractable sampling probe and the use of a standardized sampling system designed for the new particulate matter regulation in development for aircraft engines. Many of the gas-phase aircraft emissions, e.g. CO2, NOX, CO, SO2, hydrocarbons, and volatile organic compounds (VOC) were detected by the instruments in use. This study, part of the APRIDE-5 campaign, focuses on the primary VOC emissions in order to produce emission factors of VOC species for varying engine operating conditions which are the surrogates for the flight cycles. Previously, aircraft plumes were sampled in order to quantify VOCs by a proton transfer reaction quadrupole mass spectrometer (PTR-MS) [3]. This earlier study provided a preliminary knowledge on the emission of species such as methanol, acetaldehyde, acetone, benzene and toluene by varying engine thrust levels. The new setup was (i) designed to sample from the diluted engine exhaust and the new tool and (ii) used a high resolution time of flight PTR-MS with higher accuracy for many new species, therefore providing a more detailed and accurate inventory. We will present the emission factors for species that were quantified previously, as well as for many additional VOCs detected during the campaign

  2. Volcanic ash vs. sand and dust - "to stick or not to stick" in jet engines

    Science.gov (United States)

    Kueppers, U.; Song, W.; Lavallée, Y.; Hess, K. U.; Cimarelli, C.; Dingwell, D. B.

    2015-12-01

    Safe air travel activity requires clean flight corridors. But particles scattered in the atmosphere, whether volcanic ash, dust or sand, may present a critical threat to aviation safety. When these foreign particles are ingested into jet engines, whose interiors (e.g., the combustor and turbine blades) reach 1200-2000 °C, they can abrade, melt, and stick to the internal components of the engine, clogging ventilation traps of the cooling system as well as imparting substantial damage and potentially resulting in catastrophic system failure. To date, no criterion predicts ash behaviour at high temperature. Here, we experimentally develop the first quantitative model to predict melting and sticking conditions for the compositional range of volcanic ash encountered worldwide (Fig.1). The assumption that volcanic ash can be approximated by sand or dust is wholly inadequate, leading to an overestimation of sticking temperature and a correspondingly severe underestimation of the thermal hazard. Our findings confirm that the melting/softening behaviour of volcanic ash at high temperatures is essentially controlled by the composition of erupted ash - which may serve as an accurate proxy of the thermal hazard potential of volcanic ash interaction with jet engines. The criterion proposed here successfully parameterizes the potentially complex "melting" process of volcanic ash and can be used to assess the deposition probability of volcanic ash upon ingestion into hot jet engines.

  3. Measurement and characterization of fully transient diesel fuel jet processes in an optical engine with production injectors

    Science.gov (United States)

    Neal, Nicholas; Rothamer, David

    2016-10-01

    The effects of transient rate-of-injection profiles on high-pressure diesel fuel jets have been studied in an optically accessible internal combustion engine. High-speed optical imaging measurements were applied over a range of ambient conditions, fuel types, and injection parameters. This paper demonstrates that during the early part of the injection, while the liquid core is disintegrating, the penetration is functionally linked to the inviscid orifice exit velocity up until a downstream distance hypothesized to be the jet breakup length. The jets then transitioned to a mixing dominated penetration behavior afterward. Therefore, for cases that exhibit transient rate-of-injection profiles, quasi-steady penetration analytical solutions for penetration have poor agreement with the empirical data. The development of an adaptive edgefinding algorithm for accurately detecting jets in engines is detailed. These findings indicate that empirical correlations widely used throughout the engine community for estimating jet penetration do not accurately represent actual injection parameters under transient conditions.

  4. JET BREAKUP AND SPRAY FORMATION IN A DIESEL ENGINE.

    Energy Technology Data Exchange (ETDEWEB)

    GLIMM,J.; LI,X.; KIM,M.N.; OH,W.; MARCHESE,A.; SAMULYAK,R.; TZANOS,C.

    2003-06-17

    The breakup of injected fuel into spray is of key interest to the design of a fuel efficient, nonpolluting diesel engine. We report preliminary progress on the numerical simulation of diesel fuel injection spray with the front tracking code FronTier. Our simulation design is set to match experiments at ANL, and our present agreement is semi-quantitative. Future efforts will include mesh refinement studies, which will better model the turbulent flow.

  5. Development of the Compact Jet Engine Simulator from concept to useful test rig

    Science.gov (United States)

    Hoedebecke, Blake Louis

    Two Compact Jet Engine Simulator (CJES) units were designed for integrated wind tunnel acoustic experiments involving a Hybrid Wing Body (HWB) vehicle. To meet the 5.8% scale of the HWB model, Ultra Compact Combustor technology from the Air Force Research Laboratory was used. The CJES units were built and integrated with a control system in the NASA Langley Low Speed Aeroacoustic Wind Tunnel. The combustor liners, plug--vane and flow conditioner components were built in-house at Langley Research Center. The operation of the CJES units was mapped and fixes found for combustor instability tones and rig flow noise. The original concept remained true, but the internal hardware evolved through out the process. The CJES units sucssfully completed the HWB validation test and can be used for acoustic testing or propulsion integration studies that require jet engines.

  6. Non-self-sustained microwave discharge and the concept of a microwave air jet engine

    Energy Technology Data Exchange (ETDEWEB)

    Batanov, G M; Gritsinin, S I; Kossyi, I A [General Physics Institute of Russian Academy of Sciences, 119991, Vavilov Street 38, Moscow (Russian Federation)

    2002-10-21

    A new type of microwave discharge - near-surface non-self-sustained discharge (NSND) - has been realized and investigated. A physical model of this discharge is presented. For the first time NSND application for microwave air jet engines has been proposed. Measurements under laboratory conditions modelling the microwave air jet engine operation shows the qualitative agreement between the model of NSND and actual processes near the target irradiated by a powerful microwave beam. Characteristic dependences of recoil momentum of target on the background pressure and microwave pulse duration obtained in experiments are presented. Measured cost of thrust produced by the NSND is no more than 3.0 kW N{sup -1}, which is close to the predicted values.

  7. Design of a fuzzy logic controller for a jet engine fuel system

    Energy Technology Data Exchange (ETDEWEB)

    Zilouchian, A. [Florida Atlantic Univ., Dept. of Electrical Engineering, Boca Raton, FL (United States); Juliano, M.; Healy, T.; Davis, J. [Florida Atlantic Univ., Dept. of Mechanical Engineering, Boca Raton, FL (United States)

    2000-08-01

    The design, implementation and evaluation of two types of fuzzy logic controllers (FLC) are presented. The system under consideration is the control of fuel delivery in a jet engine test bench. Two methods of designing FLCs were experimented with. The first method included the development of a tool that inputs the rules, membership functions, and outputs the appropriate consequences. The second method was based on bivariate curve development and scaling. The evaluations of the proposed controllers were performed with an existing proportional-integral (PI) controller. Both of the design methodologies were proven to be superior in comparison with the conventional controller currently utilised for the control of combustion pressure on jet engines. (Author)

  8. JET ENGINE INLET DISTORTION SCREEN AND DESCRIPTOR EVALUATION

    Directory of Open Access Journals (Sweden)

    Jiří Pečinka

    2017-02-01

    Full Text Available Total pressure distortion is one of the three basic flow distortions (total pressure, total temperature and swirl distortion that might appear at the inlet of a gas turbine engine (GTE during operation. Different numerical parameters are used for assessing the total pressure distortion intensity and extent. These summary descriptors are based on the distribution of total pressure in the aerodynamic interface plane. There are two descriptors largely spread around the world, however, three or four others are still in use and can be found in current references. The staff at the University of Defence decided to compare the most common descriptors using basic flow distortion patterns in order to select the most appropriate descriptor for future department research. The most common descriptors were identified based on their prevalence in widely accessible publications. The construction and use of these descriptors are reviewed in the paper. Subsequently, they are applied to radial, angular, and combined distortion patterns of different intensities and with varied mass flow rates. The tests were performed on a specially designed test bench using an electrically driven standalone industrial centrifugal compressor, sucking air through the inlet of a TJ100 small turbojet engine. Distortion screens were placed into the inlet channel to create the desired total pressure distortions. Of the three basic distortions, only the total pressure distortion descriptors were evaluated. However, both total and static pressures were collected using a multi probe rotational measurement system.

  9. Developing Criteria for Sample Sizes in Jet Engine Analytical Component Inspections and the Associated Confidence Levels

    Science.gov (United States)

    1988-09-01

    5 Sample The samples taken from each population will not be random samples . They will be nonprobability , purposive samples . More specifically, they...section will justify why statistical techniques based on the assumption of a random sample , will be used. First, this is the only possible method of...w lu 88 12 21 029 AFIT/GSM/LSM/88S-22 DEVELOPING CRITERIA FOR SAMPLE SIZES IN JET ENGINE ANALYTICAL COMPONENT INSPECTIONS AND THE ASSOCIATED

  10. Hygroscopic properties of jet engine combustor particles during the partemis campaign

    Energy Technology Data Exchange (ETDEWEB)

    Gysel, M.; Nyeki, S.; Weingartner, E.; Baltensperger, U.; Petzold, A. [Deutsche Luft- und Raumfahrt, Oberpfaffenhofen (Germany); Wilson, C.W.

    2002-03-01

    The influence of fuel sulphur content (FSC) on particle properties from a jet engine combustor test rig was investigated during the EC-project PartEmis. Hygroscopic growth factors were measured using a Hygroscopicity Tandem Differential Mobility Analyser (H-TDMA). While particles were hydrophobic at low FSC, hygroscopic growth factors increased significantly with increasing FSC. Under similar conditions small particles were more hygroscopic than large particles. (author)

  11. Dynamic behavior of a magnetic bearing supported jet engine rotor with auxiliary bearings

    Science.gov (United States)

    Flowers, George T.; Xie, Huajun; Sinha, S. C.

    1995-01-01

    This paper presents a study of the dynamic behavior of a rotor system supported by auxiliary bearings. The steady-state behavior of a simulation model based upon a production jet engine is explored over a wide range of operating conditions for varying rotor imbalance, support stiffness, and damping. Interesting dynamical phenomena, such as chaos, subharmonic responses, and double-valued responses, are presented and discussed.

  12. Significance of chamber pressure to complex multi-phase physics in jet engine fuel injection processes

    Science.gov (United States)

    Dahms, Rainer; Oefelein, Joseph

    2014-11-01

    Injection processes in jet engines at chamber pressures in excess of the thermodynamic critical pressure of the liquid fuel are not well understood. Under some conditions, a distinct two-phase interface may not exist anymore which eliminates the presence of classical spray atomization phenomena. A comprehensive model for jet engine fuel injections is derived to quantify the conditions under which the interfacial dynamics transition to diffusion-dominated mixing processes without surface tension. At certain conditions, the model shows two-phase interfaces with substantially increased thicknesses and distinctively reduced mean free paths in comparison to ambient pressure conditions. Then, the underlying assumptions of a distinct two-phase interface do not apply anymore and the interface along with its surface tension is shown to deteriorate as it broadens substantially. As a consequence of this physical complexity, the conceptual view of spray atomization and evaporation as an appropriate model for jet engine injection processes is, contrary to conventional wisdom, questionable at certain operating conditions. Instead, a Large Eddy Simulation using a dense-fluid approximation is applied which takes the complex thermo-physics of real-fluid behavior into account.

  13. Technology of laser repair welding of nickel superalloy inner flaps of jet engine

    Directory of Open Access Journals (Sweden)

    A. Klimpel

    2011-07-01

    Full Text Available Purpose: of this paper: work out laser welding repair technology of cracked MIG 29 jet engine inner flaps made of cast nickel superalloy ŻS-3DK (ЖС-3ДК, Russian designation.Design/methodology/approach: The study were based on the analysis of laser HPDL powder INCONEL 625 welding of nickel superalloy using wide range of welding parameters to provide highest quality repair welds.Findings: Study of automatic welding technologies GTA, PTA and laser HPDL has shown that just laser welding can provide high quality repair welds. In order to establish the properties of welded joints repair cracks in the inner flap HPDL laser, studied the hardness, mechanical properties and erosive wear resistance.Research limitations/implications: It was found that only laser HPDL welding can provide high quality repair welds.Practical implications: The technology can be applied for repair cracked MIG 29 jet engine inner flaps.Originality/value: Repairing cracked MIG 29 jet engine inner flaps.

  14. A two-dimensional Euler solution for an unbladed jet engine configuration

    Science.gov (United States)

    Stewart, Mark E. M.

    1992-01-01

    A two dimensional, nonaxisymmetric Euler solution in a geometry representative of a jet engine configuration without blades is presented. The domain, including internal and external flow, is covered with a multiblock grid. In order to construct this grid, a domain decomposition technique is used to subdivide the domain, and smooth grids are dimensioned and placed in each block. The Euler solution is verified by examining five theoretical properties. The result demonstrates techniques for performing numerical solutions in complex geometries and provides a foundation for complete engine throughflow calculations.

  15. A 3-D discontinuous Galerkin Method for jet engine buzz-saw noise propagation

    Energy Technology Data Exchange (ETDEWEB)

    Remaki, M.; Habashi, W.G. [McGill Univ., Computational Fluid Dynamics Laboratory, Montreal, Quebec (Canada)]. E-mail: remaki@cfdlab.mcgill.ca; wagdi.habashi@mcgill.ca; Ait-Ali-Yahia, D. [Pratt and Whitney Canada, CFD Group, Longueuil, Quebec (Canada)]. E-mail: djaffar.Ait-Ali-Yahia@pwc.ca; Jay, A. [Pratt and Whitney Canada, Dept. of Acoustics and Installation, Longueuil, Quebec (Canada)]. E-mail: alexandre.jay@pwc.ca

    2002-07-01

    This paper presents a 3-D methodology for solving jet engine aero-acoustics problems in the presence of strong shocks and rarefactions. For example, turbofan engines suffer from Multiple Pure Tone noise, also called Buzz-saw noise, generated by the fan when the blade rotational tip speed is supersonic. These waves are composed of a series of shocks and rarefactions produced by a coalescence of shocks due to non-uniformities in the blade spacing and in the blade stagger angles, arising from manufacturing tolerances.

  16. Acoustic Pyrometry Applied to Gas Turbines and Jet Engines

    Science.gov (United States)

    Fralick, Gustave C.

    1999-01-01

    Internal gas temperature is one of the most fundamental parameters related to engine efficiency and emissions production. The most common methods for measuring gas temperature are physical probes, such as thermocouples and thermistors, and optical methods, such as Coherent Anti Stokes Raman Spectroscopy (CARS) or Rayleigh scattering. Probes are relatively easy to use, but they are intrusive, their output must be corrected for errors due to radiation and conduction, and their upper use temperature is limited. Optical methods are nonintrusive, and they measure some intrinsic property of the gas that is directly related to its temperature (e.g., lifetime or the ratio of line strengths). However, optical methods are usually difficult to use, and optical access is not always available. Lately, acoustic techniques have been receiving some interest as a way to overcome these limitations.

  17. Numerical modeling of a Jet Ignition Direct Injection (JIDI LPG engine

    Directory of Open Access Journals (Sweden)

    albert boretti

    2016-12-01

    Full Text Available The paper presents indirectly validated simulations of the operation of a LPG engine fitted with Direct Injection (DI and Jet Ignition (JI. It is demonstrated that the engine may have diesel like efficiencies and load control by quantity of fuel injected.  As the liquid propane quickly evaporates after injection in the main chamber, the main chamber mixture may be much closer to stoichiometry than a diesel for a better specific power at low engine speeds. This design also works at the high engine speeds impossible for the diesel, as combustion within the main chamber is controlled by the turbulent mixing rather than the vaporization and diffusion processes of the injected fuel of the diesel. 

  18. Alleviation of Facility/Engine Interactions in an Open-Jet Scramjet Test Facility

    Science.gov (United States)

    Albertson, Cindy W.; Emami, Saied

    2001-01-01

    Results of a series of shakedown tests to eliminate facility/engine interactions in an open-jet scramjet test facility are presented. The tests were conducted with the NASA DFX (Dual-Fuel eXperimental scramjet) engine in the NASA Langley Combustion Heated Scramjet Test Facility (CHSTF) in support of the Hyper-X program, The majority of the tests were conducted at a total enthalpy and pressure corresponding to Mach 5 flight at a dynamic pressure of 734 psf. The DFX is the largest engine ever tested in the CHSTF. Blockage, in terms of the projected engine area relative to the nozzle exit area, is 81% with the engine forebody leading edge aligned with the upper edge of the facility nozzle such that it ingests the nozzle boundary layer. The blockage increases to 95% with the engine forebody leading edge positioned 2 in. down in the core flow. Previous engines successfully tested in the CHSTF have had blockages of no more than 51%. Oil flow studies along with facility and engine pressure measurements were used to define flow behavior. These results guided modifications to existing aeroappliances and the design of new aeroappliances. These changes allowed fueled tests to be conducted without facility interaction effects in the data with the engine forebody leading edge positioned to ingest the facility nozzle boundary layer. Interaction effects were also reduced for tests with the engine forebody leading edge positioned 2 in. into the core flow, however some interaction effects were still evident in the engine data. A new shroud and diffuser have been designed with the goal of allowing fueled tests to be conducted with the engine forebody leading edge positioned in the core without facility interaction effects in the data. Evaluation tests of the new shroud and diffuser will be conducted once ongoing fueled engine tests have been completed.

  19. Hybrid Active/Passive Jet Engine Noise Suppression System

    Science.gov (United States)

    Parente, C. A.; Arcas, N.; Walker, B. E.; Hersh, A. S.; Rice, E. J.

    1999-01-01

    A novel adaptive segmented liner concept has been developed that employs active control elements to modify the in-duct sound field to enhance the tone-suppressing performance of passive liner elements. This could potentially allow engine designs that inherently produce more tone noise but less broadband noise, or could allow passive liner designs to more optimally address high frequency broadband noise. A proof-of-concept validation program was undertaken, consisting of the development of an adaptive segmented liner that would maximize attenuation of two radial modes in a circular or annular duct. The liner consisted of a leading active segment with dual annuli of axially spaced active Helmholtz resonators, followed by an optimized passive liner and then an array of sensing microphones. Three successively complex versions of the adaptive liner were constructed and their performances tested relative to the performance of optimized uniform passive and segmented passive liners. The salient results of the tests were: The adaptive segmented liner performed well in a high flow speed model fan inlet environment, was successfully scaled to a high sound frequency and successfully attenuated three radial modes using sensor and active resonator arrays that were designed for a two mode, lower frequency environment.

  20. Experimental Study of the Jet Engine Exhaust Flow Field of Aircraft and Blast Fences

    Directory of Open Access Journals (Sweden)

    Haifu Wang

    2015-04-01

    Full Text Available A combined blast fence is introduced in this paper to improve the solid blast fences and louvered ones. Experiments of the jet engine exhaust flow (hereinafter jet flow for short field and tests of three kinds of blast fences in two positions were carried out. The results show that the pressure and temperature at the centre of the jet flow decrease gradually as the flow moves farther away from the nozzle. The pressure falls fast with the maximum rate of 41.7%. The dynamic pressure 150 m away from the nozzle could reach 58.8 Pa, with a corresponding wind velocity of 10 m/s. The temperature affected range of 40°C is 113.5×20 m. The combined blast fence not only reduces the pressure of the flow in front of it but also solves the problems that the turbulence is too strong behind the solid blast fences and the pressure is too high behind the louvered blast fences. And the pressure behind combined blast fence is less than 10 Pa. The height of the fence is related to the distance from the jet nozzle. The nearer the fence is to the nozzle, the higher it is. When it is farther from the nozzle, its height can be lowered.

  1. Condensation of water vapor and carbon dioxide in the jet exhausts of rocket engines: 1. Model calculation of the physical conditions in a jet exhaust

    Science.gov (United States)

    Platov, Yu. V.; Alpatov, V. V.; Klyushnikov, V. Yu.

    2014-01-01

    Model calculations have been performed for the temperature and pressure of combustion products in the jet exhaust of rocket engines of last stages of Proton, Molniya, and Start launchers operating in the upper atmosphere at altitudes above 120 km. It has been shown that the condensation of water vapor and carbon dioxide can begin at distances of 100-150 and 450-650 m away from the engine nozzle, respectively.

  2. Recent development of melting process and criteria for jet engine alloys. Saikin no jet engine yo gokin no criteria to yosei gijutsu

    Energy Technology Data Exchange (ETDEWEB)

    Degawa, T. (The University of British Columbia, (Canada))

    1991-09-20

    Super-alloys and Ti alloy were taken up as key materials for jet engines to describe their design criteria and the current state in destruction mechanical approaches. Also, as a solution to improving the material reliability, the clean alloy melting technique was touched upon as to its current state. Changes in high-temperature creep life and tenacity in the super-alloys (directions in the improvement efforts) are shown. In the recent movements in the clean melting technique, attentions are drawn on the ingot melting method using a cold hearth as an excellent method. Discussions were given on sizes of defects in the materials that affect dynamic destruction of rotating bodies such as turbines, and the relations are shown between the initial permissible defect size and the yield stress in various types of super-alloys. 31 refs., 11 figs., 3 tabs.

  3. Jet propagation and evaporation in diesel-engine injection. Strahlausbreitung und Verdampfung bei der dieselmotorischen Einspritzung

    Energy Technology Data Exchange (ETDEWEB)

    Stojanoff, C.G.; Schaller, J.K.; Ante, A.

    1992-01-01

    The first two years of the research project were dedicated to the development of a holographic method and its application in the study on diesel fuel jets. Recording and reconstruction geometries were optimized to allow individual droplets to be resolved even at maximal droplet densities. Pretrials were used to test the holographic method. Resolution of droplet densities of 10[sup 11] droplets per cbm has been achieved to date. Maximum speed measured was 200 m/s. First images of diesel injection jet prove that it is possible to perform holographic measurements. The third year of the project will involve measurements to be performed and interpreted in the chamber under diesel-engine conditions. (orig./HW).

  4. HBL variability at high energies: clues on jet structure and driving engine

    Science.gov (United States)

    Costamante, Luigi

    High-energy-peaked BLLac objects (HBL) are characterized by the highest energy electrons in the whole blazar class. They show strong variability on many different timescales, in particular in the X-ray and gamma-ray bands, which are close to the peaks of their spectral energy distribution (SED). This variability carries information on two different aspects: on how the central engine drives the jet (long time series analysis) and on the details of the acceleration and emission processes in each single dissipative event. In the latter case, the study of flares (down to few minutes in gamma-rays) with time-resolved spectroscopy and correlations in different bands is now providing new clues on the structure of the jet, exposing the limits of the one-zone interpretation for the SED peaks. I will discuss the recent progresses allowed by multi-wavelength campaigns with new-generation instruments.

  5. Early afterglow, magnetized central engine, and a quasi-universal jet configuration for long GRBs

    CERN Document Server

    Zhang, B; Kobayashi, S; Lloyd-Ronning, N M; Mészáros, P; Dai, Xinyu; Kobayashi, Shiho; Lloyd-Ronning, Nicole M.; Meszaros, Peter; Zhang, Bing

    2003-01-01

    Two separate topics are discussed. (1) We describe the classifications of the long GRB early afterglow lightcurves within the framework of the fireball shock model, focusing on the interplay between the reverse and forward shock emission components. We will also provide evidence that the central engine of at least two bursts are entrained with strong magnetic fields, and discuss the implications of this result for our understanding of the GRB phenomenon; (2) We argue that the current gamma-ray burst (GRB) and X-ray flash (XRF) data are consistent with a picture that all GRB-XRF jets are structured and quasi-universal, with a typical Gaussian-like jet structure.

  6. Cooperative Multi-Agent Mobile Sensor Platforms for Jet Engine Inspection: Concept and Implementation

    Science.gov (United States)

    Litt, Jonathan S.; Wong, Edmond; Krasowski, Michael J.; Greer, Lawrence C.

    2003-01-01

    Cooperative behavior algorithms utilizing swarm intelligence are being developed for mobile sensor platforms to inspect jet engines on-wing. Experiments are planned in which several relatively simple autonomous platforms will work together in a coordinated fashion to carry out complex maintenance-type tasks within the constrained working environment modeled on the interior of a turbofan engine. The algorithms will emphasize distribution of the tasks among multiple units; they will be scalable and flexible so that units may be added in the future; and will be designed to operate on an individual unit level to produce the desired global effect. This proof of concept demonstration will validate the algorithms and provide justification for further miniaturization and specialization of the hardware toward the true application of on-wing in situ turbine engine maintenance.

  7. Development of a Temperature Sensor for Jet Engine and Space Mission Applications

    Science.gov (United States)

    Patterson, Richard L.; Hammoud, Ahmad; Elbuluk, Malik; Culley, Dennis

    2008-01-01

    Electronics for Distributed Turbine Engine Control and Space Exploration Missions are expected to encounter extreme temperatures and wide thermal swings. In particular, circuits deployed in a jet engine compartment are likely to be exposed to temperatures well exceeding 150 C. To meet this requirement, efforts exist at the NASA Glenn Research Center (GRC), in support of the Fundamental Aeronautics Program/Subsonic Fixed Wing Project, to develop temperature sensors geared for use in high temperature environments. The sensor and associated circuitry need to be located in the engine compartment under distributed control architecture to simplify system design, improve reliability, and ease signal multiplexing. Several circuits were designed using commercial-off-the-shelf as well as newly-developed components to perform temperature sensing at high temperatures. The temperature-sensing circuits will be described along with the results pertaining to their performance under extreme temperature.

  8. A quadratic programming framework for constrained and robust jet engine health monitoring

    Science.gov (United States)

    Borguet, S.; Léonard, O.

    2009-09-01

    Kalman filters are largely used in the jet engine community for condition monitoring purpose. This algorithm gives a good estimate of the engine condition provided that the residuals between the model prediction and the measurements are zero-mean, Gaussian random variables. In the case of sensor faults, this assumption does not hold anymore and consequently, the diagnosis is spoiled. This contribution presents a recursive estimation algorithm based on a Quadratic Programming (QP) formulation which provides robustness against sensor faults and allows constraints on the health parameters to be specified. The improvements in estimation accuracy brought by this new algorithm are illustrated on a series of typical test-cases that may be encountered on current turbofan engines.

  9. Organ printing: computer-aided jet-based 3D tissue engineering.

    Science.gov (United States)

    Mironov, Vladimir; Boland, Thomas; Trusk, Thomas; Forgacs, Gabor; Markwald, Roger R

    2003-04-01

    Tissue engineering technology promises to solve the organ transplantation crisis. However, assembly of vascularized 3D soft organs remains a big challenge. Organ printing, which we define as computer-aided, jet-based 3D tissue-engineering of living human organs, offers a possible solution. Organ printing involves three sequential steps: pre-processing or development of "blueprints" for organs; processing or actual organ printing; and postprocessing or organ conditioning and accelerated organ maturation. A cell printer that can print gels, single cells and cell aggregates has been developed. Layer-by-layer sequentially placed and solidified thin layers of a thermo-reversible gel could serve as "printing paper". Combination of an engineering approach with the developmental biology concept of embryonic tissue fluidity enables the creation of a new rapid prototyping 3D organ printing technology, which will dramatically accelerate and optimize tissue and organ assembly.

  10. Jet Engine Powerloss in Ice Particle Conditions: An Aviation Industry Problem

    Science.gov (United States)

    Strapp, J. W.

    2009-09-01

    Since about the 1990, there have been in excess of 100 engine powerloss events in jet aircraft that have now been attributed to the ingestion of ice particles. These powerloss events are observed in essentially all engine types, and on all airframes. Almost all cases have occurred in the vicinity of deep convection usually associated with warm and moist atmospheres. Events have occurred all throughout the world, although there is a somewhat higher concentration in the area of southeast Asia. Powerloss can result from stall, surge, flameout and rollback events in the engine. Many are momentary, with engines relighting automatically, while others require a manual engine relight. In some cases, particularly in rollback cases on smaller commuter-transport aircraft, engine power has only been recovered by melting of ice buildup in the engine below the freezing level. There have been cases of multiple simultaneous engine powerloss, and one case of a landing with no engine power. The frequency of the events, and the potential for multiple-engine powerloss, has led the FAA to note that that these occurrences constitute a significant safety issue. Analysis of the events using aircraft flight data recorder information, pilot interviews, standard meteorological radar and satellite data, and information from several past flight test programs, have led to the conclusion that the powerloss is due to ice buildup in the engine from high concentrations of ice particles in the atmosphere, and that supercooled LWC is not required. This is an unconventional form of icing that had not been previously considered possible by engine designers. The Engine Harmonization Working Group (EHWG), an industry-led committee composed of engine manufacturers, airframe manufacturers, regulators, and government agencies have been studying the powerloss issue since 2004, and have suggested a 4-part technical plan to resolve the issue, which includes improvement of instrumentation to measure high ice

  11. 40 CFR 1045.660 - How do I certify outboard or personal watercraft engines for use in jet boats?

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 32 2010-07-01 2010-07-01 false How do I certify outboard or personal watercraft engines for use in jet boats? 1045.660 Section 1045.660 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF EMISSIONS FROM SPARK-IGNITION PROPULSION MARINE ENGINES AND VESSELS...

  12. Testing exposure of a jet engine to a dilute volcanic-ash cloud

    Science.gov (United States)

    Guffanti, M.; Mastin, L. G.; Schneider, D. J.; Holliday, C. R.; Murray, J. J.

    2013-12-01

    An experiment to test the effects of volcanic-ash ingestion by a jet engine is being planned for 2014 by a consortium of U.S. Government agencies and engine manufacturers, under the auspices of NASA's Vehicle Integrated Propulsion Research Program. The experiment, using a 757-type engine, will be an on-ground, on-wing test carried out at Edwards Air Force Base, California. The experiment will involve the use of advanced jet-engine sensor technology for detecting and diagnosing engine health. A primary test objective is to determine the effect on the engine of many hours of exposure to ash concentrations (1 and 10 mg/cu m) representative of ash clouds many 100's to >1000 km from a volcanic source, an aviation environment of great interest since the 2010 Eyjafjallajökull, Iceland, eruption. A natural volcanic ash will be used; candidate sources are being evaluated. Data from previous ash/aircraft encounters, as well as published airborne measurements of the Eyjafjallajökull ash cloud, suggest the ash used should be composed primarily of glassy particles of andesitic to rhyolitic composition (SiO2 of 57-77%), with some mineral crystals, and a few tens of microns in size. Collected ash will be commercially processed less than 63 microns in size with the expectation that the ash particles will be further pulverized to smaller sizes in the engine during the test. For a nominally planned 80 hour test at multiple ash-concentration levels, the test will require roughly 500 kg of processed (appropriately sized) ash to be introduced into the engine core. Although volcanic ash clouds commonly contain volcanic gases such as sulfur dioxide, testing will not include volcanic gas or aerosol interactions as these present complex processes beyond the scope of the planned experiment. The viscous behavior of ash particles in the engine is a key issue in the experiment. The small glassy ash particles are expected to soften in the engine's hot combustion chamber, then stick to cooler

  13. Demonstration of a Packaged Capacitive Pressure Sensor System Suitable for Jet Turbofan Engine Health Monitoring

    Science.gov (United States)

    Scardelletti, Maximilian C.; Jordan, Jennifer L.; Meredith, Roger D.; Harsh, Kevin; Pilant, Evan; Usrey, Michael W.; Beheim, Glenn M.; Hunter, Gary W.; Zorman, Christian A.

    2016-01-01

    In this paper, the development and characterization of a packaged pressure sensor system suitable for jet engine health monitoring is demonstrated. The sensing system operates from 97 to 117 MHz over a pressure range from 0 to 350 psi and a temperature range from 25 to 500 deg. The sensing system consists of a Clapp-type oscillator that is fabricated on an alumina substrate and is comprised of a Cree SiC MESFET, MIM capacitors, a wire-wound inductor, chip resistors and a SiCN capacitive pressure sensor. The pressure sensor is located in the LC tank circuit of the oscillator so that a change in pressure causes a change in capacitance, thus changing the resonant frequency of the sensing system. The chip resistors, wire-wound inductors and MIM capacitors have all been characterized at temperature and operational frequency, and perform with less than 5% variance in electrical performance. The measured capacitive pressure sensing system agrees very well with simulated results. The packaged pressure sensing system is specifically designed to measure the pressure on a jet turbofan engine. The packaged system can be installed by way of borescope plug adaptor fitted to a borescope port exposed to the gas path of a turbofan engine.

  14. Carbonaceous aerosol in jet engine exhaust: emission characteristics and implications for heterogeneous chemical reactions

    Energy Technology Data Exchange (ETDEWEB)

    Petzold, A.; Schroeder, F.P.; Kaercher, B. [Deutsches Zentrum fuer Luft- und Raumfahrt, Wessling (Germany). Institut fuer Physik der Atmosphaere; Stroem, J. [Stockholm University (Sweden). Dept. of Meteorology

    1999-08-01

    Characteristic parameters of black carbon aerosol (BC) emitted from jet engine were measured during ground tests and in-flight behind the same aircraft. Size distribution features were a primary BC mode at a model diameter D {approx} 0.045 {mu}m, and a BC agglomeration mode at D < 0.2 {mu}m. The total BC number concentration at the engine exit was 2.9 x 10{sup 7} cm{sup -3} with good agreement between model results and in-flight measured number concentrations of non-volatile particles with D {>=} 0.014 {mu}m. A comparison between total number concentration of BC particles and the non-volatile fraction of the total aerosol at the exit plane suggests that the non-volatile fraction of jet engine exhaust aerosol consists almost completely of BC. In-flight BC mass emission indices ranged from 0.11 to 0.15 g BC (kg fuel){sup -1}. The measured in-flight particle emission value was 1.75 {+-} 0.15 x 10{sup 15} kg{sup -1} with corresponding ground test values of 1.0-8.7 x 10{sup 14} kg{sup -1}. Both size distribution properties and mass emission indices can be scaled from ground test to in-flight conditions. Implications for atmosphere BC loading, BC and cirrus interaction and the potential of BC for perturbation of atmospheric chemistry are briefly outlined. (author)

  15. High-fidelity Simulation of Jet Noise from Rectangular Nozzles . [Large Eddy Simulation (LES) Model for Noise Reduction in Advanced Jet Engines and Automobiles

    Science.gov (United States)

    Sinha, Neeraj

    2014-01-01

    This Phase II project validated a state-of-the-art LES model, coupled with a Ffowcs Williams-Hawkings (FW-H) far-field acoustic solver, to support the development of advanced engine concepts. These concepts include innovative flow control strategies to attenuate jet noise emissions. The end-to-end LES/ FW-H noise prediction model was demonstrated and validated by applying it to rectangular nozzle designs with a high aspect ratio. The model also was validated against acoustic and flow-field data from a realistic jet-pylon experiment, thereby significantly advancing the state of the art for LES.

  16. Future Jet Technologies. Part B. F-35 Future Risks v. JS-Education of Pilots & Engineers

    Science.gov (United States)

    Gal-Or, Benjamin

    2011-09-01

    Design of “Next-Generation” airframes based on supermarket-jet-engine-components is nowadays passé. A novel integration methodology [Gal-Or, “Editorial-Review, Part A”, 2011, Gal-Or, “Vectored Propulsion, Supermaneuverability and Robot Aircraft”, Springer Verlag, Gal-Or, Int'l. J. of Thermal and Fluid Sciences 7: 1-6, 1998, “Introduction”, 2011] is nowadays in. For advanced fighter aircraft it begins with JS-based powerplant, which takes up to three times longer to mature vis-à-vis the airframe, unless “committee's design” enforces a dormant catastrophe. Jet Steering (JS) or Thrust Vectoring Flight Control, is a classified, integrated engine-airframe technology aimed at maximizing post-stall-maneuverability, flight safety, efficiency and flight envelopes of manned and unmanned air vehicles, especially in the “impossible-to-fly”, post-stall flight domains where the 100+ years old, stall-spin-limited, Conventional Flight Control fails. Worldwide success in adopting the post-stall, JS-revolution, opens a new era in aviation, with unprecedented design variables identified here for a critical review of F-35 future risks v. future fleets of jet-steered, pilotless vehicles, like the X-47B/C. From the educational point of view, it is also instructive to comprehend the causes of long, intensive opposition to adopt post-stall, JS ideas. A review of such debates may also curb a future opposition to adopt more advanced, JS-based technologies, tests, strategies, tactics and missions within the evolving air, marine and land applications of JS. Most important, re-education of pilots and engineers requires adding post-stall, JS-based studies to curriculum & R&D.

  17. Spreading dynamic of viscous volcanic ash in stimulated jet engine conditions

    Science.gov (United States)

    song, wenjia; Lavallée, Yan; Hess, Kai-Uwe; Kueppers, Ulrich; Cimarelli, Corrado

    2016-04-01

    The ingestion of volcanic ash is widely recognised as a potentially fatal hazard for aircraft operation. The volcanic ash deposition process in a jet turbine is potentially complex. Volcanic ash in the air stream enters the inner liners of the combustors and partially or completely melts under the flames up to 2000 °C, at which point part of the ash deposits in the combustor fuel nozzle. Molten volcanic particles within high energy airflow escape the combustor to enter the turbine and impact the stationary (e.g., inlet nozzle guide vanes) and rotating airfoils (e.g., first stage high-pressure turbine blades) at high speed (up to Mach 1.25) in different directions, with the result that ash may stick, flow and remain liquid or solidify. Thus, the wetting behaviour of molten volcanic ash particle is fundamental to investigate impingement phenomena of ash droplet on the surface of real jet engine operation. The topic of wetting has received tremendous interest from both fundamental and applied points of view. However, due to the interdisciplinary gap between jet engine engineering and geology science, explicit investigation of wetting behaviour of volcanic ash at high temperature is in its infancy. We have taken a big step towards meeting this challenge. Here, we experimentally and theoretically investigate the wetting behaviour of viscous volcanic ash over a wide temperature range from 1100 to 1550 °C using an improved sessile-drop method. The results of our experiment demonstrate that temperature and viscosity play a critical role in determining the wetting possibility and governing the spreading kinetics of volcanic ash at high temperatures. Our systemic analysis of spreading of molten volcanic ash systems allows us to report on the fundamental differences between the mechanisms controlling spreading of organic liquids at room temperature and molten volcanic ash droplets.

  18. In Operation Detection and Correction of Rotor Imbalance in Jet Engines Using Active Vibration Control

    Science.gov (United States)

    Manchala, Daniel W.; Palazzolo, Alan B.; Kascak, Albert F.; Montague, Gerald T.; Brown, Gerald V.; Lawrence, Charles; Klusman, Steve

    1994-01-01

    Jet Engines may experience severe vibration due to the sudden imbalance caused by blade failure. This research investigates employment of on board magnetic bearings or piezoelectric actuators to cancel these forces in flight. This operation requires identification of the source of the vibrations via an expert system, determination of the required phase angles and amplitudes for the correction forces, and application of the desired control signals to the magnetic bearings or piezo electric actuators. This paper will show the architecture of the software system, details of the control algorithm used for the sudden imbalance correction project described above, and the laboratory test results.

  19. A multiblock grid generation technique applied to a jet engine configuration

    Science.gov (United States)

    Stewart, Mark E. M.

    1992-01-01

    Techniques are presented for quickly finding a multiblock grid for a 2D geometrically complex domain from geometrical boundary data. An automated technique for determining a block decomposition of the domain is explained. Techniques for representing this domain decomposition and transforming it are also presented. Further, a linear optimization method may be used to solve the equations which determine grid dimensions within the block decomposition. These algorithms automate many stages in the domain decomposition and grid formation process and limit the need for human intervention and inputs. They are demonstrated for the meridional or throughflow geometry of a bladed jet engine configuration.

  20. Jet engine nozzle exit configurations, including projections oriented relative to pylons, and associated systems and methods

    Science.gov (United States)

    Mengle, Vinod G. (Inventor); Thomas, Russell H. (Inventor)

    2012-01-01

    Nozzle exit configurations and associated systems and methods are disclosed. An aircraft system in accordance with one embodiment includes a jet engine exhaust nozzle having an internal flow surface and an exit aperture, with the exit aperture having a perimeter that includes multiple projections extending in an aft direction. Aft portions of individual neighboring projections are spaced apart from each other by a gap, and a geometric feature of the multiple can change in a monotonic manner along at least a portion of the perimeter. Projections near a support pylon and/or associated heat shield can have particular configurations, including greater flow immersion than other projections.

  1. Investigation of Hygro-Thermal Aging on Carbon/Epoxy Materials for Jet Engine Fan Sections

    Science.gov (United States)

    Kohlman, Lee W.; Roberts, Gary D.; Miller, Sandi G.; Pereira, J. Michael

    2011-01-01

    This poster summarizes 2 years of aging on E862 epoxy and E862 epoxy with triaxial braided T700s carbon fiber composite. Several test methods were used to characterize chemical, physical, and mechanical properties of both the resin and composite materials. The aging cycle that was used included varying temperature and humidity exposure. The goal was to evaluate the environmental effects on a potential jet engine fan section material. Some changes were noted in the resin which resulted in increased brittleness, though this did not significantly affect the tensile and impact test results. A potential decrease in compression strength requires additional investigation.

  2. In Operation Detection and Correction of Rotor Imbalance in Jet Engines Using Active Vibration Control

    Science.gov (United States)

    Manchala, Daniel W.; Palazzolo, Alan B.; Kascak, Albert F.; Montague, Gerald T.; Brown, Gerald V.; Lawrence, Charles; Klusman, Steve

    1994-01-01

    Jet Engines may experience severe vibration due to the sudden imbalance caused by blade failure. This research investigates employment of on board magnetic bearings or piezoelectric actuators to cancel these forces in flight. This operation requires identification of the source of the vibrations via an expert system, determination of the required phase angles and amplitudes for the correction forces, and application of the desired control signals to the magnetic bearings or piezo electric actuators. This paper will show the architecture of the software system, details of the control algorithm used for the sudden imbalance correction project described above, and the laboratory test results.

  3. Noise Characteristics of a Four-Jet Impingement Device Inside a Broadband Engine Noise Simulator

    Science.gov (United States)

    Brehm, Christoph; Housman, Jeffrey A.; Kiris, Cetin C.; Hutcheson, Florence V.

    2015-01-01

    The noise generation mechanisms for four directly impinging supersonic jets are investigated employing implicit large eddy simulations with a higher-order accurate weighted essentially non-oscillatory shock-capturing scheme. Impinging jet devices are often used as an experimental apparatus to emulate a broadband noise source. Although such devices have been used in many experiments, a detailed investigation of the noise generation mechanisms has not been conducted before. Thus, the underlying physical mechanisms that are responsible for the generation of sound waves are not well understood. The flow field is highly complex and contains a wide range of temporal and spatial scales relevant for noise generation. Proper orthogonal decomposition of the flow field is utilized to characterize the unsteady nature of the flow field involving unsteady shock oscillations, large coherent turbulent flow structures, and the sporadic appearance of vortex tubes in the center of the impingement region. The causality method based on Lighthill's acoustic analogy is applied to link fluctuations of flow quantities inside the source region to the acoustic pressure in the far field. It will be demonstrated that the entropy fluctuation term in the Lighthill's stress tensor plays a vital role in the noise generation process. Consequently, the understanding of the noise generation mechanisms is employed to develop a reduced-order linear acoustic model of the four-jet impingement device. Finally, three linear acoustic FJID models are used as broadband noise sources inside an engine nacelle and the acoustic scattering results are validated against far-field acoustic experimental data.

  4. Design of Combustor for Long-range Ram-jet Engine and Performance of Rectangular Analog

    Science.gov (United States)

    Rayle, Warren D; Koch, Richard G

    1954-01-01

    The report describes the design of a piloted combustor intended for a ram-jet engine of long flight range. The unit comprises a large annular basket of V-type cross-section, the inner surface of which is slotted and bent into small V-gutters. At the trailing edge of the basket, eight V-gutters are used to propagate the flame into the main stream. A rectangular analog of this combustor was tested at air-flow conditions corresponding to those that might be obtained during cruise. At these conditions, combustion efficiencies of as much as 90 percent were calculated for the combustor at the design equivalence ratio of 0.52. The performance of the unit was relatively insensitive to mounting and flow variables; the greatest effect on efficiency was that of the manner and location of the fuel injection. A full-scale version of this combustor has been designed for a 48-inch-diameter engine.

  5. Analysis of complex decisionmaking processes. [with application to jet engine development

    Science.gov (United States)

    Hill, J. D.; Ollila, R. G.

    1978-01-01

    The analysis of corporate decisionmaking processes related to major system developments is unusually difficult because of the number of decisionmakers involved in the process and the long development cycle. A method for analyzing such decision processes is developed and illustrated through its application to the analysis of the commercial jet engine development process. The method uses interaction matrices as the key tool for structuring the problem, recording data, and analyzing the data to establish the rank order of the major factors affecting development decisions. In the example, the use of interaction matrices permitted analysts to collect and analyze approximately 50 factors that influenced decisions during the four phases of the development cycle, and to determine the key influencers of decisions at each development phase. The results of this study indicate that the cost of new technology installed on an aircraft is the prime concern of the engine manufacturer.

  6. Mathematical model of an indirect action fuel flow controller for aircraft jet engines

    Science.gov (United States)

    Tudosie, Alexandru-Nicolae

    2017-06-01

    The paper deals with a fuel mass flow rate controller with indirect action for aircraft jet engines. The author has identified fuel controller's main parts and its operation mode, then, based on these observations, one has determined motion equations of each main part, which have built system's non-linear mathematical model. In order to realize a better study this model was linearised (using the finite differences method) and then adimensionalized. Based on this new form of the mathematical model, after applying Laplace transformation, the embedded system (controller+engine) was described by the block diagram with transfer functions. Some Simulink-Matlab simulations were performed, concerning system's time behavior for step input, which lead to some useful conclusions and extension possibilities.

  7. Static and dynamic novelty detection methods for jet engine health monitoring.

    Science.gov (United States)

    Hayton, Paul; Utete, Simukai; King, Dennis; King, Steve; Anuzis, Paul; Tarassenko, Lionel

    2007-02-15

    Novelty detection requires models of normality to be learnt from training data known to be normal. The first model considered in this paper is a static model trained to detect novel events associated with changes in the vibration spectra recorded from a jet engine. We describe how the distribution of energy across the harmonics of a rotating shaft can be learnt by a support vector machine model of normality. The second model is a dynamic model partially learnt from data using an expectation-maximization-based method. This model uses a Kalman filter to fuse performance data in order to characterize normal engine behaviour. Deviations from normal operation are detected using the normalized innovations squared from the Kalman filter.

  8. Biomimetic thermal barrier coating in jet engine to resist volcanic ash deposition

    Science.gov (United States)

    Song, Wenjia; Major, Zsuzsanna; Schulz, Uwe; Muth, Tobias; Lavallée, Yan; Hess, Kai-Uwe; Dingwell, Donald B.

    2017-04-01

    The threat of volcanic ash to aviation safety is attracting extensive attention when several commercial jet aircraft were damaged after flying through volcanic ash clouds from the May 1980 eruptions of Mount St. Helen in Washington, U.S. and especially after the air traffic disruption in 2010 Eyjafjallajökull eruption. A major hazard presented by volcanic ash to aircraft is linked to the wetting and spreading of molten ash droplets on engine component surfaces. Due to the fact ash has a lower melting point, around 1100 °C, than the gas temperature in the hot section (between 1400 to 2000 °C), this cause the ash to melt and potentially stick to the internal components (e.g., combustor and turbine blades), this cause the ash to melt and potentially stick to the internal components of the engine creating, substantial damage or even engine failure after ingestion. Here, inspiring form the natural surface of lotus leaf (exhibiting extreme water repellency, known as 'lotus effect'), we firstly create the multifunctional surface thermal barrier coatings (TBCs) by producing a hierarchical structure with femtosecond laser pulses. In detail, we investigate the effect of one of primary femtosecond laser irradiation process parameter (scanning speed) on the hydrophobicity of water droplets onto the two kinds of TBCs fabricated by electron-beam physical vapor deposition (EB-PVD) and air plasma spray (APS), respectively as well as their corresponding to morphology. It is found that, comparison with the original surface (without femtosecond laser ablation), all of the irradiated samples demonstrate more significant hydrophobic properties due to nanostructuring. On the basis of these preliminary room-temperature results, the wettability of volcanic ash droplets will be analysed at the high temperature to constrain the potential impact of volcanic ash on the jet engines.

  9. Modeling absorption spectra for detection of the combustion products of jet engines by laser remote sensing.

    Science.gov (United States)

    Voitsekhovskaya, Olga K; Kashirskii, Danila E; Egorov, Oleg V; Shefer, Olga V

    2016-05-10

    The absorption spectra of exhaust gases (H2O, CO, CO2, NO, NO2, and SO2) and aerosol (soot and Al2O3) particles were modeled at different temperatures for the first time and suitable spectral ranges were determined for conducting laser remote sensing of the combustion products of jet engines. The calculations were conducted on the basis of experimental concentrations of the substances and the sizes of the aerosol particles. The temperature and geometric parameters of jet engine exhausts were also taken from the literature. The absorption spectra were obtained via the line-by-line method, making use of the spectral line parameters from the authors' own high-temperature databases (for NO2 and SO2 gases) and the HITEMP 2010 database, and taking into account atmospheric transmission. Finally, the theoretical absorption spectra of the exhaust gases were plotted at temperatures of 400, 700, and 1000 K, and the impact of aerosol particles on the total exhaust spectra was estimated in spectral ranges suitable for remote sensing applications.

  10. Application of numerical analysis method to jet engine combustion design. Jet engine yo nenshoki no sekkei ni okeru suchi kaiseki no tekiyo

    Energy Technology Data Exchange (ETDEWEB)

    Negoro, T.; Arai, M.; Kuyama, T.; Nakahata, T.; Hirokawa, M. (Kawasaki Heavy Industries, Ltd., Tokyo (Japan))

    1993-01-20

    This paper describes features and applications of numerical analysis for jet engine combustor design. The numerical analysis for flow fields in a combustor has set a limitation on objects to be analyzed for each component element in the combustor or each design element, and carried out the analysis upon selecting basic formulas and models. The numerical analysis is effective to predict qualitatively the effects on flow patterns in the whole combustor liner interior or temperature distributions in the combustor liner interior, but is not sufficiently effective for use as quantitative evaluation. An application suggested that a parallel shape is more preferable that does not squeeze a flow outlet on the outer side that can be expected of providing sufficiently large recirculation flow region, as a result of analyzing the flow patterns around fuel injection valves. Dump diffuser analysis revealed that the above shape is preferable in supplying air stably from the annulus part into the liner interior through air holes. It was verified that the analysis of flows in the combustor liner has identified features of the flows qualitatively. 4 refs., 13 figs.

  11. Numerical flow analysis using the CFD method in axial flow compressor used for a jet engine. Jet engine yo jikuryu asshukuki no nagare kaiseki

    Energy Technology Data Exchange (ETDEWEB)

    Arai, M.; Hashimoto, K.; Suga, S.; Matsuoka, A. (Kawasaki Heavy Industries, Ltd., Tokyo (Japan))

    1992-10-20

    Numerical fluid dynamics is used to solve numerically the Navier-Stokes equations including viscosity using a computer for the purpose of evaluating aerodynamic performance of compressor cascades, an element to constitute a jet engine. This paper discusses effectiveness and problems in this computation. A viscous flow analysis using this method was applied to actual two-dimensional compressor cascades that work in transonic regions. The analytic result may be summarized as follows: The method has high analytic accuracy and can predict aerodynamic characteristics if no separation occurs or it is limited in a flow field; however, the method does not assure quantitative accuracy for a flow accompanying separation and strong in non-steadiness; at this stage the method cannot be applied to three-dimensional problems, but is effective in identifying a flow field qualitatively; and while the supercomputer VP 200 required only two to three minutes to analyze a two-dimensional flow with 14000 lattices, the three-dimensional viscosity analysis required five hours. This method may be used effectively in a basic discussion stage for the initial design and in a simulation stage for improving a design. 11 refs., 18 figs., 2 tabs.

  12. Chemistry Characterization of Jet Aircraft Engine Particulate by XPS: Results from APEX III

    Science.gov (United States)

    Vander Wal, Randy L.; Bryg, Victoria M.

    2014-01-01

    This paper reports XPS analysis of jet exhaust particulate from a B737, Lear, ERJ, and A300 aircraft during the APEX III NASA led field campaign. Carbon hybridization and bonding chemistry are identified by high-resolution scans about the C1s core-shell region. Significant organic content as gauged by the sp3/sp2 ratio is found across engines and platforms. Polar oxygen functional groups include carboxylic, carbonyl and phenol with combined content of 20 percent or more. By lower resolution survey scans various elements including transition metals are identified along with lighter elements such as S, N, and O in the form of oxides. Burning additives within lubricants are probable sources of Na, Ba, Ca, Zn, P and possibly Sn. Elements present and their percentages varied significantly across all engines, not revealing any trend or identifiable cause for the differences, though the origin is likely the same for the same element when observed. This finding suggests that their presence can be used as a tracer for identifying soots from aircraft engines as well as diagnostic for monitoring engine performance and wear.

  13. Chemistry characterization of jet aircraft engine particulate matter by XPS: Results from APEX III

    Science.gov (United States)

    Vander Wal, Randy L.; Bryg, Victoria M.; Huang, Chung-Hsuan

    2016-09-01

    This paper reports X-ray photoelectron spectroscopy (XPS) analysis of jet exhaust particulate matter (PM) from a B737, Lear, ERJ and A300 aircraft during the APEX III NASA led field campaign. Carbon hybridization and bonding chemistry are identified by high-resolution scans about the C1s core-shell region. Significant organic content as gauged by the sp3/sp2 ratio is found across engines and powers. Polar oxygen functional groups include carboxylic, carbonyl and phenol with combined content of 20% or more. By survey scans various elements including transition metals are identified along with lighter elements such as S, N and O in the form of oxides. Additives within lubricants are probable sources of Na, Ba, Ca, Zn, P and possibly Sn. Elements present and their percentages varied significantly across all engines, not revealing any trend or identifiable cause for the differences, though the origin is likely the same for the same element when observed. This finding suggests that their collective presence could serve as an environmental tracer for identifying PM originating from aircraft engines and serving as a diagnostic for engine performance and wear.

  14. Comparison of the constituents of two jet engine lubricating oils and their volatile pyrolytic degradation products.

    Science.gov (United States)

    van Netten, C; Leung, V

    2000-03-01

    Leaking oil seals in jet engines, at locations prior to the compressor stage, can be a cause of smoke in the cabins of BAe-146 aircraft. Compressed combustion air is bled off to pressurize the cabin and to provide a source of fresh air. Bleed air is diverted from a location just prior to the combustion chamber at a temperature around 500 degrees C. To prevent oil breakdown products from entering the cabin air, catalytic converters have been used to clean the air. During an oil seal failure this device becomes overloaded and smoke is observed in the cabin. Some aircraft companies have removed the catalytic converters and claim an improvement in air quality. During an oil seal failure, however, the flight crew is potentially exposed to the thermal breakdown products of the engine oils. Because very little is known regarding the thermal breakdown products of jet engine lubrication oils, two commercially available oils were investigated under laboratory conditions at 525 degrees C to measure the release of CO, CO2,NO2, and HCN as well as volatiles which were analyzed using GC-Mass spectrometry in an attempt to see if the neurotoxic agents tricresyl phosphates (TCPs) and trimethyl propane phosphate (TMPP) would be present or formed. TMPP was not found in these experiments. Some CO2 was generated along with CO which reached levels in excess of 100 ppm. HCN and NO2 were not detected. GC compositions of the two bulk oils and their breakdown products were almost identical. The presence of TCPs was confirmed in the bulk oils and in the volatiles. Localized condensation in the ventilation ducts and filters in the air conditioning packs are likely the reason why the presence of TCPs has not been demonstrated in cabin air. It was recommended that this needed to be verified in aircraft.

  15. Jet Car Track Site

    Data.gov (United States)

    Federal Laboratory Consortium — Located in Lakehurst, New Jersey, the Jet Car Track Site supports jet cars with J57 engines and has a maximum jet car thrust of 42,000 pounds with a maximum speed of...

  16. OT2_cceccare_5: Peering into the engine of a jet-driven bowshock : TMC1B1

    Science.gov (United States)

    Ceccarelli, C.

    2011-09-01

    Jet-driven bowshocks seem to be rather ubiquitous in star-forming regions. If the large-scale bow is commonly observed and its kinematics, the actual engine of the outflow, the Mach disk region where the gas is accelerated, has never been detected until now. Recently, we have found observational evidence of the long-searched engine of outflows in the giant molecular bowshock TMC1B1 together with the driving jet, in Taurus (d=140 pc). which allows Herschel to resolve the cooling region of the shock. We propose to use Herschel to investigate the dynamics and physical structure of TMC1B1, a potential benchmark for jet-driven bowshocks studies.

  17. Acoustic interactions between an altitude test facility and jet engine plumes: Theory and experiments

    Science.gov (United States)

    Ahuja, K. K.; Jones, R. R., III; Tam, C. K.; Massey, K. C.; Fleming, A. J.

    1992-01-01

    The overall objective of the described effort was to develop an understanding of the physical mechanisms involved in the flow/acoustic interactions experienced in full-scale altitude engine test facilities. This is done by conducting subscale experiments and through development of a theoretical model. Model cold jet experiments with an axisymmetric convergent nozzle are performed in a test setup that stimulates a supersonic jet exhausting into a cylindrical diffuser. The measured data consist of detailed flow visualization data and acoustic spectra for a free and a ducted plume. It is shown that duct resonance is most likely responsible by theoretical calculations. Theoretical calculations also indicate that the higher discrete tones observed in the measurements are related to the screech phenomena. Limited experiments on the sensitivity of a free 2-D, C-D nozzle to externally imposed sound are also presented. It is shown that a 2-D, C-D nozzle with a cutback is less excitable than a 2-D C-D nozzle with no cutback. At a pressure ratio of 1.5 unsteady separation from the diverging walls of the nozzle is noticed. This separation switches from one wall to the opposite wall thus providing an unsteady deflection of the plume. It is shown that this phenomenon is related to the venting provided by the cutback section.

  18. Investigation of Flow Conditioners for Compact Jet Engine Simulator Rig Noise Reduction

    Science.gov (United States)

    Doty, Michael J.; Haskin, Henry H.

    2011-01-01

    The design requirements for two new Compact Jet Engine Simulator (CJES) units for upcoming wind tunnel testing lead to the distinct possibility of rig noise contamination. The acoustic and aerodynamic properties of several flow conditioner devices are investigated over a range of operating conditions relevant to the CJES units to mitigate the risk of rig noise. An impinging jet broadband noise source is placed in the upstream plenum of the test facility permitting measurements of not only flow conditioner self-noise, but also noise attenuation characteristics. Several perforated plate and honeycomb samples of high porosity show minimal self-noise but also minimal attenuation capability. Conversely, low porosity perforated plate and sintered wire mesh conditioners exhibit noticeable attenuation but also unacceptable self-noise. One fine wire mesh sample (DP450661) shows minimal selfnoise and reasonable attenuation, particularly when combined in series with a 15.6 percent open area (POA) perforated plate upstream. This configuration is the preferred flow conditioner system for the CJES, providing up to 20 dB of broadband attenuation capability with minimal self-noise.

  19. Volatile properties of jet engine combustor particles during the hot-end simulator (HES) PartEmis campaign

    Energy Technology Data Exchange (ETDEWEB)

    Nyeki, S.; Gysel, M.; Weingartner, E.; Baltensperger, U.; Petzold, A.; Wilson, C.W.

    2003-03-01

    Test rig measurements on a combustor in 2001 were extended in 2002 on a Hot-End Simulator (HES), designed to simulate the turbine section of a jet engine. Volatile properties were measured using a Volatility Tandem Differential Mobility Analyser (VTDMA). Initial analyses indicate that the HES has a negligible influence on particle properties. (author)

  20. A joint numerical and experimental study of the jet of an aircraft engine installation with advanced techniques

    Science.gov (United States)

    Brunet, V.; Molton, P.; Bézard, H.; Deck, S.; Jacquin, L.

    2012-01-01

    This paper describes the results obtained during the European Union JEDI (JEt Development Investigations) project carried out in cooperation between ONERA and Airbus. The aim of these studies was first to acquire a complete database of a modern-type engine jet installation set under a wall-to-wall swept wing in various transonic flow conditions. Interactions between the engine jet, the pylon, and the wing were studied thanks to ¤advanced¥ measurement techniques. In parallel, accurate Reynolds-averaged Navier Stokes (RANS) simulations were carried out from simple ones with the Spalart Allmaras model to more complex ones like the DRSM-SSG (Differential Reynolds Stress Modef of Speziale Sarkar Gatski) turbulence model. In the end, Zonal-Detached Eddy Simulations (Z-DES) were also performed to compare different simulation techniques. All numerical results are accurately validated thanks to the experimental database acquired in parallel. This complete and complex study of modern civil aircraft engine installation allowed many upgrades in understanding and simulation methods to be obtained. Furthermore, a setup for engine jet installation studies has been validated for possible future works in the S3Ch transonic research wind-tunnel. The main conclusions are summed up in this paper.

  1. Service the Two-Piece Flo-Jet Carburetor. Fuel System. Student Manual 3. Small Engine Repair Series. First Edition.

    Science.gov (United States)

    Hill, Pamela

    This student manual, part of a small-engine repair series on servicing fuel systems, is designed for use by special needs students in Texas. The manual explains in pictures and short sentences, written on a low reading level, the job of servicing two-piece flo-jet carburetors. Along with the steps of this repair job, specific safety and caution…

  2. Real Time Diagnostics of Jet Engine Exhaust Plumes Using a Chirped QC Laser Spectrometer

    Science.gov (United States)

    Hay, K. G.; Duxbury, G.; Langford, N.

    2010-06-01

    Quantitative measurements of real-time variations of the chemical composition of a jet engine exhaust plume is demonstrated using a 4.86 μmn intra-pulse quantum cascade laser spectrometer. The measurements of the gas turbine exhaust were carried out in collaboration with John Black and Mark Johnson at Rolls Royce. The recording of five sets of averaged spectra a second has allowed us to follow the build up of the combustion products within the exhaust, and to demonstrate the large variation of the integrated absorption of these absorption lines with temperature. The absorption cross sections of the lines of both carbon monoxide and water increase with temperature, whereas those of the three main absorption lines of carbon dioxide decrease. At the steady state limit the absorption lines of carbon dioxide are barely visible, and the spectrum is dominated by absorption lines of carbon monoxide and water.

  3. A new performance evaluation scheme for jet engine vibration signal denoising

    Science.gov (United States)

    Sadooghi, Mohammad Saleh; Esmaeilzadeh Khadem, Siamak

    2016-08-01

    Denoising of a cargo-plane jet engine compressor vibration signal is investigated in this article. Discrete wavelet transform and two families of Donoho-Johnston and parameter method thresholding, are applied to vibration signal. Eighty four combinations of wavelet thresholding and mother wavelet are evaluated. A new performance evaluation scheme for optimal selection of mother wavelet and thresholding method combination is proposed in this paper, which is make a trade off between four performance criteria of signal to noise ratio, percentage root mean square difference, Cross-correlation, and mean square error. Dmeyer mother wavelet (dmey) combined with Rigorous SURE thresholding has the maximum trade off value and was selected as the most appropriate combination for denoising of the signal. It was shown that inappropriate combination leads to data losing. Also higher performance of proposed trade off with respect to other criteria was proven graphically.

  4. High-speed, high-temperature magnetic bearings for jet turbine engine application

    Energy Technology Data Exchange (ETDEWEB)

    Mekhiche, M.; Nichols, S.; Hevenhill, D.; Oleksy, J.; Young, J.; Kirtley, J.L. [SatCon Technology Corporation, Cambridge, MA (United States)

    2000-08-01

    In order to double today's jet turbine engines' propulsion capability, lightweight, high-efficiency, high-speed and hightemperature components are sought. These requirements put the conventional components such as the mechanical bearings under excessive constraints and make them obsolete. In this context, SatCon Technology Corporation has developed a high-speed, high- temperature (50 krpm, 600 deg. C) magnetic bearing system that has the potential of meeting the requirements described above. This magnetic bearing system, comprised of two radial and one double acting thrust bearings, was successfully tested to 50,000 rpm. This paper describes the development of this system from its design, through its fabrication and final testing. Details on the system and component requirements are presented, along with a step-by step design and trade-off analysis. Test data and their discussion are provided as well. (orig.)

  5. Traction coefficient in a roller-inner ring EHD contact in a jet engine roller bearing

    Energy Technology Data Exchange (ETDEWEB)

    Sottomayor, A. [INEGI-CETRIB, Faculdade de Engenharia da Universidade do Porto (Portugal); Campos, A. [INEGI-CETRIB, Faculdade de Engenharia da Universidade do Porto (Portugal); Seabra, J. [Dept. de Engenharia Mecanica e Gestao Industrial, Faculdade de Engenharia da Universidade do Porto (Portugal)

    1997-08-01

    A simplified non-newtonian EHD model developed previously is used for the analysis of a roller-inner ring contact in a jet engine roller bearing. The lubricant behaves according to the viscoelastic rheological model, with a Ree-Eyring fluid, and the lubricant parameters are function of the pressure, temperature and rolling speed. The traction coefficient results obtained with this model are compared with previous experimental results obtained in a twin-disk machine. Finally, the influence of the operating conditions (pressure, temperature, rolling speed and slide-to-roll ratio) and of the waviness of the contacting surfaces, on the traction coefficient inside the roller-inner ring contact, is analysed. (orig.)

  6. Development and testing of dry chemicals in advanced extinguishing systems for jet engine nacelle fires

    Science.gov (United States)

    Altman, R. L.; Ling, A. C. (Editor); Mayer, L. A.; Myronik, D. J.

    1979-01-01

    The effectiveness of dry chemical in extinguishing and delaying reignition of fires resulting from hydrocarbon fuel leaking onto heated surfaces such as can occur in jet engine nacelles is studied. The commercial fire extinguishant dry chemical tried are sodium and potassium bicarbonate, carbonate, chloride, carbamate (Monnex), metal halogen, and metal hydroxycarbonate compounds. Synthetic and preparative procedures for new materials developed, a new concept of fire control by dry chemical agents, descriptions of experiment assemblages to test dry chemical fire extinguishant efficiencies in controlling fuel fires initiated by hot surfaces, comparative testing data for more than 25 chemical systems in a 'static' assemblage with no air flow across the heated surface, and similar comparative data for more than ten compounds in a dynamic system with air flows up to 350 ft/sec are presented.

  7. Ultra small engines for model aircraft; Mokei hikokiyo chokogata jet engine

    Energy Technology Data Exchange (ETDEWEB)

    Noda, H.

    1998-12-10

    Turbojet engines for model aircraft are described. The first one was the T-240 of JPX Corporation, consisting of a 1-stage centrifugal compressor, an annular combustor, and a 1-stage axial flow turbine, fueled by LPG (liquid petroleum gas). Liquefied propane widely available on the market was first chosen as the fuel because regulations over high-pressure gas were rather lax in Europe. Since liquid fuel was easier to handle, however, shift occurred, from liquefied gas to JP-4 and then to kerosene. As for the means of ignition, electric sparks are handy for igniting kerosene, and electrically heated glow plugs for fuels higher in volatility. As for the means of injection, liquid fuel is gasified in a heated fuel pipe or aerified under pressure. For start-up, compressed air and motors driven by Ni-Cd cells are in common use. Start-up, ignition, combustion, self-sustained combustion, and then the throttle is slowly opened for taking off. Every manufacture is now ready to provide a control for throttling fuel flow upon detecting excess speed or excess exhaust temperature, which is important for the protection of gas turbines. (NEDO)

  8. Effects of Nozzle Scale, Total Temperature and an Afterburner on Jet Noise from a Pre-Cooled Turbojet Engine

    Science.gov (United States)

    Araki, Mikiya; Sano, Takayuki; Fukuda, Masayuki; Kojima, Takayuki; Taguchi, Hideyuki; Nishida, Shunsuke; Imamura, Osamu; Shiga, Seiichi; Tsue, Mitsuhiro

    Effects of nozzle scale, total temperature, and an afterburner on jet noise characteristics from a pre-cooled turbojet engine are investigated experimentally. In JAXA (Japan Aerospace Exploration Agency), a pre-cooled turbojet engine for an HST (Hypersonic transport) is under development. In the present study, 1.0%- and 2.4%-scaled models of the rectangular plug nozzle (Nozzles I and II) are manufactured, and the jet noise characteristics are investigated under a wide range of total temperatures. For Nozzle I, no air-heater is utilized and the total temperature is 290K. For Nozzle II, a pebble heater and an afterburner (AB) are utilized upstream of the nozzle model, and the total temperature is varied from 520K (pebble heater) to 1540K (pebble heater + AB). The total pressure is set at 0.27 and 0.30MPa(a) for both nozzle models. Jet noise is measured using a high-frequency microphone set at 135 deg from the engine inlet, and normalized jet noise spectra are obtained based on AUjn law and Helmholtz number. For cases without afterburner, the normalized spectra agrees well regardless of the nozzle scale and total temperature where the velocity index lies from n = 7.7 to 9.2, and the correlation factor between the two facilities is shown to be about 1dB. For the case with afterburner, the normalized spectrum does not agree with other conditions where the velocity index n seems to be about 4.

  9. Engineering anisotropic biphasic Janus-type polymer nanofiber scaffold networks via centrifugal jet spinning.

    Science.gov (United States)

    Khang, Alex; Ravishankar, Prashanth; Krishnaswamy, Aditya; Anderson, Patrick K; Cone, Stephanie G; Liu, Zizhao; Qian, Xianghong; Balachandran, Kartik

    2017-11-01

    Biphasic materials, comprised of an ordered arrangement of two different material phases within a material, have the potential for a wide variety of applications including filtration, protective clothing and tissue engineering. This study reports for the first time, a process for engineering biphasic Janus-type polymeric nanofiber (BJPNF) networks via the centrifugal jet spinning technique. BJPNF alignment and fiber diameter was dependent on fabrication rotational speed as well as solution composition. The biphasic character of these BJPNFs, which was controlled via the rotational speed of fabrication, was confirmed at the individual nanofiber scale using energy dispersive X-ray spectroscopy, and at the bulk, macro-scale using attenuated total reflectance-Fourier transform infrared spectroscopy. Biphasic character was also demonstrated at the functional level via differing affinities on either side of the BJPNF for cell attachment. Our work thus presents a method for fabricating BJPNF scaffold networks where there might be a need for different properties on either side of a material. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 2455-2464, 2017. © 2016 Wiley Periodicals, Inc.

  10. Instabilities in the Gamma Ray Burst central engine. What makes the jet variable?

    Science.gov (United States)

    Janiuk, Agnieszka; Yuan, Ye-Fei; Perna, Rosalba; Di Matteo, Tiziana

    2011-02-01

    Both types of long and short gamma ray bursts involve a stage of a hyper-Eddington accretion of hot and dense plasma torus onto a newly born black hole. The prompt gamma ray emission originates in jets at some distance from this `central engine' and in most events is rapidly variable, having a form of sipkes and subpulses. This indicates at the variable nature of the engine itself, for which a plausible mechanism is an internal instability in the accreting flow. We solve numerically the structure and evolution of the neutrino-cooled torus. We take into account the detailed treatment of the microphysics in the nuclear equation of state that includes the neutrino trapping effect. The models are calculated for both Schwarzschild and Kerr black holes. We find that for sufficiently large accretion rates (>~10Msolar s-1 for non-rotating black hole, and >~1Msolar s-1 for rotating black hole, depending on its spin), the inner regions of the disk become opaque, while the helium nuclei are being photodissociated. The sudden change of pressure in this region leads to the development of a viscous and thermal instability, and the neutrino pressure acts similarly to the radiation pressure in sub-Eddington disks. In the case of rapidly rotating black holes, the instability is enhanced and appears for much lower accretion rates. We also find the important and possibly further destabilizing role of the energy transfer from the rotating black hole to the torus via the magnetic coupling.

  11. Instabilities in the Gamma Ray Burst central engine. What makes the jet variable?

    CERN Document Server

    Yuan, Ye-Fei; Di Matteo, Tiziana

    2010-01-01

    Both types of long and short gamma ray bursts involve a stage of a hyper-Eddington accretion of hot and dense plasma torus onto a newly born black hole. The prompt gamma ray emission originates in jets at some distance from this 'central engine' and in most events is rapidly variable, having a form of spikes and subpulses. This indicates at the variable nature of the engine itself, for which a plausible mechanism is an internal instability in the accreting flow. We solve numerically the structure and evolution of the neutrino-cooled torus. We take into account the detailed treatment of the microphysics in the nuclear equation of state that includes the neutrino trapping effect. The models are calculated for both Schwarzschild and Kerr black holes. We find that for sufficiently large accretion rates (> 10 Msun/s for non-rotating black hole, and >1 Msun/s for rotating black hole, depending on its spin), the inner regions of the disk become opaque, while the helium nuclei are being photodissociated. The sudden c...

  12. Small Engine Technology (SET) - Task 13 ANOPP Noise Prediction for Small Engines: Jet Noise Prediction Module, Wing Shielding Module, and System Studies Results

    Science.gov (United States)

    Lieber, Lysbeth; Golub, Robert (Technical Monitor)

    2000-01-01

    This Final Report has been prepared by AlliedSignal Engines and Systems, Phoenix, Arizona, documenting work performed during the period May 1997 through June 1999, under the Small Engines Technology Program, Contract No. NAS3-27483, Task Order 13, ANOPP Noise Prediction for Small Engines. The report specifically covers the work performed under Subtasks 4, 5 and 6. Subtask 4 describes the application of a semi-empirical procedure for jet noise prediction, subtask 5 describes the development of a procedure to predict the effects of wing shielding, and subtask 6 describes the results of system studies of the benefits of the new noise technology on business and regional aircraft.

  13. Three-dimensional simulations of long duration gamma-ray burst jets: time scales from variable engines

    CERN Document Server

    Loopez-Camara, Diego; Morsony, Brian J

    2016-01-01

    Gamma-ray burst light curves are characterized by marked variability, each showing unique properties. The origin of such variability, at least for a fraction of long GRBs, may be the result of an unsteady central engine. It is thus important to study the effects that an episodic central engine has on the jet propagation and, eventually, on the prompt emission within the collapsar scenario. Thus, in this study we follow the interaction of pulsed outflows with their progenitor stars with hydrodynamic numerical simulations in both two and three dimensions. We show that the propagation of unsteady jets is affected by the interaction with the progenitor material well after the break-out time, especially for jets with long quiescent times, comparable to or larger than a second. We also show that this interaction can lead to an asymmetric behavior in which pulse durations and quiescent periods are systematically different. After the pulsed jets drill through the progenitor and the interstellar medium, we find that, ...

  14. Aeroengine. Development of a finishing robot for jet engine parts; Kokukiyo enigne. Buhin shiage robot no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Manabe, T.; Kametani, A.; Iwamoto, M.; Danjo, K.; Hishida, H.; Ninomiya, T. [Kawasaki Heavy Industries, Ltd., Kobe (Japan)

    2000-04-01

    Kawasaki Heavy Industries, Ltd. (KHI) has developed a precise finishing robot system and applied it to the finishing processes of jet engine parts. There has been a strong need for such a system as finishing processes are both labor intensive and time-consuming activities. Realization of a suitable solution has been held back in the past due to the delicate treatment required by the fine and complicated parts. However, by developing a device with the ability to control the tool/work contact force during operation, KHI has succeeded in producing the new robotic finishing system. The system is capable of performing many types of finishing operations, such as chamfering, deburring and brushing. Systems have now been and will further be introduced into the jet engine division of KHI. Already they are contributing to labor saving, cost reduction, and processing quality control. KHI will continue to promote rationalization of production processes by introducing varieties of our robot systems where needed. (author)

  15. Engineering hybrid polymer-protein super-aligned nanofibers via rotary jet spinning.

    Science.gov (United States)

    Badrossamay, Mohammad R; Balachandran, Kartik; Capulli, Andrew K; Golecki, Holly M; Agarwal, Ashutosh; Goss, Josue A; Kim, Hansu; Shin, Kwanwoo; Parker, Kevin Kit

    2014-03-01

    Cellular microenvironments are important in coaxing cells to behave collectively as functional, structured tissues. Important cues in this microenvironment are the chemical, mechanical and spatial arrangement of the supporting matrix in the extracellular space. In engineered tissues, synthetic scaffolding provides many of these microenvironmental cues. Key requirements are that synthetic scaffolds should recapitulate the native three-dimensional (3D) hierarchical fibrillar structure, possess biomimetic surface properties and demonstrate mechanical integrity, and in some tissues, anisotropy. Electrospinning is a popular technique used to fabricate anisotropic nanofiber scaffolds. However, it suffers from relatively low production rates and poor control of fiber alignment without substantial modifications to the fiber collector mechanism. Additionally, many biomaterials are not amenable for fabrication via high-voltage electrospinning methods. Hence, we reasoned that we could utilize rotary jet spinning (RJS) to fabricate highly aligned hybrid protein-polymer with tunable chemical and physical properties. In this study, we engineered highly aligned nanofiber constructs with robust fiber alignment from blends of the proteins collagen and gelatin, and the polymer poly-ε-caprolactone via RJS and electrospinning. RJS-spun fibers retain greater protein content on the surface and are also fabricated at a higher production rate compared to those fabricated via electrospinning. We measured increased fiber diameter and viscosity, and decreasing fiber alignment as protein content increased in RJS hybrid fibers. RJS nanofiber constructs also demonstrate highly anisotropic mechanical properties mimicking several biological tissue types. We demonstrate the bio-functionality of RJS scaffold fibers by testing their ability to support cell growth and maturation with a variety of cell types. Our highly anisotropic RJS fibers are therefore able to support cellular alignment

  16. New technology for controlling NOx from jet engine test cells. Phase 1. Final report, August 1988-February 1989

    Energy Technology Data Exchange (ETDEWEB)

    Lyon, R.K.

    1995-01-01

    For some time the U.S. Air Force has been concerned with NOx emissions from jet engine test cells operated by the Air Force. While there are no regulations limiting the NOx emissions of these facilities, such regulations could develop in the near future and would pose significant problems for the Air Force because no available technology is suited for application to jet engine test cells. This report describes laboratory studies of a new NOx control process based on the surprising ability of barium oxide to rapidly capture NO, a process that could be ideally suited to controlling NOx emission from jet engine test cells. Thus, experiments were done in which a simulated exhaust gas containing NO was passed through a bed of either granular barium oxide or barium oxide supported on high-strength alumina. Quantitative NO removals were achieved at space velocities ranging from 2010 to 28,000 v/v/hr temperatures from 21 deg C to 610 deg C, oxygen concentrations of 1.1 to 15.3 percent, and initial NO concentrations from 94 to 1700 ppm. When NO2 was present in the simulated exhaust, it was also removed. The barium oxide was able to capture NO and NO2 in amounts up to at least 23.5 percent of its initial weight. The practical implication is that NOx emissions of a jet engine test cell could be controlled by replacing the acoustic panels now used to decrease the cell`s emission of sound with a set of panel bed filters filled with barium oxide. These panel bed filters would also absorb sound, could fit in the space in the test cell now occupied by the acoustic panels, and would remove NO and NO2 from the exhaust before it is discharged to the environment. This NOx removal would occur spontaneously. without any actions by the personnel operating the test cell and without distracting them in any way from their normal tasks.

  17. Neurobehavioral and respiratory findings in jet engine repair workers: A comparison of exposed and unexposed volunteers.

    Science.gov (United States)

    Kilburn, K H

    1999-04-01

    Workers repairing jet engines had respiratory, rheumatic, and neurobehavioral symptoms. They had welded and ground stainless steel parts using hard metal tools and cleaned metal with chlorinated and fluorinated organic solvents. We compared 154 workers and 112 unexposed subjects, all volunteers of similar ages and with similar educational levels, for abnormalities on chest radiographs, spirometric measurements, and questionnaires. Also appraised were performance of reaction time, balance, blink reflex latency, color discrimination, Culture Fair, vocabulary, slotted pegboard, trail making A and B, profile of mood states (POMS), and frequencies of 35 symptoms. Compared to unexposed subjects, workers had significantly more respiratory symptoms but no differences in pulmonary function. They had significantly prolonged simple and choice reaction time (P<0.0001), and abnormal balance with eyes open and eyes closed (P<0. 0001), and abnormal color discrimination. Blink reflex latency was abnormal in both exposed workers and in local unexposed compared to other reference groups. Focus of the inquiry on lung disease helped ensure that for neurobehavioral tests confounding factors were minimal and known biases were small. We tentatively attribute the neurobehavioral impairments and increased symptom frequencies to chlorinated solvent exposure. Excessive respiratory symptoms are attributed to welding stainless steel combined with cigarette smoking. Specifically, manganese exposure may have affected the respiratory and the central nervous systems.

  18. Ballistic Impact Response of Kevlar 49 and Zylon under Conditions Representing Jet Engine Fan Containment

    Science.gov (United States)

    Pereira, J. Michael; Revilock, Duane M.

    2007-01-01

    A ballistic impact test program was conducted to provide validation data for the development of numerical models of blade out events in fabric containment systems. The impact response of two different fiber materials - Kevlar 49 (E.I. DuPont Nemours and Company) and Zylon AS (Toyobo Co., Ltd.) was studied by firing metal projectiles into dry woven fabric specimens using a gas gun. The shape, mass, orientation and velocity of the projectile were varied and recorded. In most cases the tests were designed such that the projectile would perforate the specimen, allowing measurement of the energy absorbed by the fabric. The results for both Zylon and Kevlar presented here represent a useful set of data for the purposes of establishing and validating numerical models for predicting the response of fabrics under conditions simulating those of a jet engine blade release situation. In addition some useful empirical observations were made regarding the effects of projectile orientation and the relative performance of the different materials.

  19. Numerical investigation on super-cooled large droplet icing of fan rotor blade in jet engine

    Science.gov (United States)

    Isobe, Keisuke; Suzuki, Masaya; Yamamoto, Makoto

    2014-10-01

    Icing (or ice accretion) is a phenomenon in which super-cooled water droplets impinge and accrete on a body. It is well known that ice accretion on blades and vanes leads to performance degradation and has caused severe accidents. Although various anti-icing and deicing systems have been developed, such accidents still occur. Therefore, it is important to clarify the phenomenon of ice accretion on an aircraft and in a jet engine. However, flight tests for ice accretion are very expensive, and in the wind tunnel it is difficult to reproduce all climate conditions where ice accretion can occur. Therefore, it is expected that computational fluid dynamics (CFD), which can estimate ice accretion in various climate conditions, will be a useful way to predict and understand the ice accretion phenomenon. On the other hand, although the icing caused by super-cooled large droplets (SLD) is very dangerous, the numerical method has not been established yet. This is why SLD icing is characterized by splash and bounce phenomena of droplets and they are very complex in nature. In the present study, we develop an ice accretion code considering the splash and bounce phenomena to predict SLD icing, and the code is applied to a fan rotor blade. The numerical results with and without the SLD icing model are compared. Through this study, the influence of the SLD icing model is numerically clarified.

  20. An experimental study of fault propagation in a jet-engine controller. M.S. Thesis

    Science.gov (United States)

    Choi, Gwan Seung

    1990-01-01

    An experimental analysis of the impact of transient faults on a microprocessor-based jet engine controller, used in the Boeing 747 and 757 aircrafts is described. A hierarchical simulation environment which allows the injection of transients during run-time and the tracing of their impact is described. Verification of the accuracy of this approach is also provided. A determination of the probability that a transient results in latch, pin or functional errors is made. Given a transient fault, there is approximately an 80 percent chance that there is no impact on the chip. An empirical model to depict the process of error exploration and degeneration in the target system is derived. The model shows that, if no latch errors occur within eight clock cycles, no significant damage is likely to happen. Thus, the overall impact of a transient is well contained. A state transition model is also derived from the measured data, to describe the error propagation characteristics within the chip, and to quantify the impact of transients on the external environment. The model is used to identify and isolate the critical fault propagation paths, the module most sensitive to fault propagation and the module with the highest potential of causing external pin errors.

  1. Study on development of ejector of Bubble Jet Engine (BJE) - measurement of thrust -

    Energy Technology Data Exchange (ETDEWEB)

    Ono, B; Nakashima, K; Shigematsu, T; Morishita, K, E-mail: ono@post.cc.sasebo.ac.j [Sasebo National College of Technology1-1, Okishin-cho, Sasebo City, Nagasaki Pref., 857-1193 (Japan)

    2009-02-01

    The AUV (Autonomous Under-water Vehicle), which is used for the present seabed investigations, has obtained the thrust with the screw driven by the battery. However, it has a disadvantage because of its size and cost. Therefore, this research is carried out to propose the Bubble Jet Engine (BJE) as an alternative propulsion device. It can directly transform combustion energy into kinetic energy, so it is expected that BJE can also rise the level of propulsion efficiency. This research aims at measuring exhaled mass flow rate and thrust to design ejectors, which become the core of BJE, and exploring practical possibility of BJE. Vertical type gas-water ejector experimental apparatus for measuring water entrainment was employed in order to understand the characteristics of operation conditions, such as inlet distance, air pressure of nozzle, diameter of nozzle, and so on. In addition, experiments for measuring the thrust in the condition of ejector were executed with horizontal type apparatus in water. However, the influence of the ejector to improve thrust can't have been recognized with high-pressure air at room temperature yet.

  2. Characterization of Synthetic GTL Jet Fuel for use in Gas Turbine Engines

    Science.gov (United States)

    Sadr, Reza; Kannaiyan, Kumaran

    2010-11-01

    Stringent emission regulations have instigated the search for alternative-clean source of energy. Recently, Gas-to-Liquid (GTL) fuel has grabbed the global attention by its clean combustion characteristics owing to the absence of aromatics and Sulphur. However, this will introduce potential risks and benefits. Last fall Qatar airways has proven the feasibility of using GTL as a potential alternative clean fuel by a 3200 mile flight using a fuel blend of 50% JetA + 50% GTL. Researchers from Texas A & M University at Qatar (TAMUQ) in collaboration with their counterparts in Rolls-Royce (RR), UK, and German Aerospace Laboratory (DLR) are in a joint effort to establish an in-depth characterization of the combustion performance of GTL fuel in gas turbine engines. In TAMUQ, the research focus is to investigate the spray characteristics of GTL fuels. The results will be compared with that of standard fuel and correlate with combustion results to gain insights on GTL performance. This will help designers to optimize the nozzle geometry to improve the combustor performance. The objective of this talk is to introduce this ongoing effort and to discuss the experimental facility and preliminary results.

  3. Study on development of ejector of Bubble Jet Engine (BJE) - measurement of thrust -

    Science.gov (United States)

    Ono, B.; Nakashima, K.; Shigematsu, T.; Morishita, K.

    2009-02-01

    The AUV (Autonomous Under-water Vehicle), which is used for the present seabed investigations, has obtained the thrust with the screw driven by the battery. However, it has a disadvantage because of its size and cost. Therefore, this research is carried out to propose the Bubble Jet Engine (BJE) as an alternative propulsion device. It can directly transform combustion energy into kinetic energy, so it is expected that BJE can also rise the level of propulsion efficiency. This research aims at measuring exhaled mass flow rate and thrust to design ejectors, which become the core of BJE, and exploring practical possibility of BJE. Vertical type gas-water ejector experimental apparatus for measuring water entrainment was employed in order to understand the characteristics of operation conditions, such as inlet distance, air pressure of nozzle, diameter of nozzle, and so on. In addition, experiments for measuring the thrust in the condition of ejector were executed with horizontal type apparatus in water. However, the influence of the ejector to improve thrust can't have been recognized with high-pressure air at room temperature yet.

  4. Finite difference time domain modeling of steady state scattering from jet engines with moving turbine blades

    Science.gov (United States)

    Ryan, Deirdre A.; Langdon, H. Scott; Beggs, John H.; Steich, David J.; Luebbers, Raymond J.; Kunz, Karl S.

    1992-01-01

    The approach chosen to model steady state scattering from jet engines with moving turbine blades is based upon the Finite Difference Time Domain (FDTD) method. The FDTD method is a numerical electromagnetic program based upon the direct solution in the time domain of Maxwell's time dependent curl equations throughout a volume. One of the strengths of this method is the ability to model objects with complicated shape and/or material composition. General time domain functions may be used as source excitations. For example, a plane wave excitation may be specified as a pulse containing many frequencies and at any incidence angle to the scatterer. A best fit to the scatterer is accomplished using cubical cells in the standard cartesian implementation of the FDTD method. The material composition of the scatterer is determined by specifying its electrical properties at each cell on the scatterer. Thus, the FDTD method is a suitable choice for problems with complex geometries evaluated at multiple frequencies. It is assumed that the reader is familiar with the FDTD method.

  5. The influence of walls on jet propagation and ignition under diesel engine conditions. Einfluss von Waenden auf Strahlausbreitung und Zuendverhalten unter dieselmotorischen Bedingungen

    Energy Technology Data Exchange (ETDEWEB)

    Xu Huanxin.

    1991-08-01

    This research on the influence of walls on jet propagation and ingnition behaviour of a diesel jet was carried out in a pressure chamber with different wall inserts. By using two-side schlieren optics and other optical measuring methods it was possible to identify jet characteristics, especially locations of ignition and ingition delays in the injection jet precisely and to analyse them statistically. Wall temperature, wall spacing, impact angle, chamber air temperature and chamber pressure, injection pressure and injection quantity were vaired within the range important for a diesel engine. (orig./HW).

  6. A methodology for the evaluation of the turbine jet engine fragment threat to generic air transportable containers

    Energy Technology Data Exchange (ETDEWEB)

    Harding, D.C.; Pierce, J.D.

    1993-06-01

    Uncontained, high-energy gas turbine engine fragments are a potential threat to air-transportable containers carried aboard jet aircraft. The threat to a generic example container is evaluated by probability analyses and penetration testing to demonstrate the methodology to be used in the evaluation of a specific container/aircraft/engine combination. Fragment/container impact probability is the product of the uncontained fragment release rate and the geometric probability that a container is in the path of this fragment. The probability of a high-energy rotor burst fragment from four generic aircraft engines striking one of the containment vessels aboard a transport aircraft is approximately 1.2 {times} 10{sup {minus}9} strikes/hour. Finite element penetration analyses and tests can be performed to identify specific fragments which have the potential to penetrate a generic or specific containment vessel. The relatively low probability of engine fragment/container impacts is primarily due to the low release rate of uncontained, hazardous jet engine fragments.

  7. Negative chemiions formed in jet fuel combustion: new insights from jet engine and laboratory measurements using a quadrupole ion trap mass spectrometer apparatus

    Energy Technology Data Exchange (ETDEWEB)

    Kiendler, A.; Aberle, S.; Arnold, F. [Max Planck Institute for Nuclaear Physics, Heidelberg (Germany). Atmospheric Physics Div.

    2000-07-01

    Measurements were made of mass numbers and composition of negative chemiions produced in jet fuel combustion in the exhaust of a jet engine and of a burner in the laboratory. The measurements made by a novel quadrupole ion trap mass spectrometer apparatus revealed the presence of three major ion families: ions containing an HSO{sub 4}{sup -} ''core's' or an NO{sub 3}{sup -} ''core's' and {sup O}HC-ions{sup .} The latter which contain C and H atoms and in part also 0 atoms can be divided into two subfamilies with even and odd mass numbers. It is proposed that the O HC ions are formed by free-electron attachment to HC and OHC molecules and/or ion-molecule reactions of primary negative chemiions with HC and OHC molecules. It is also proposed that HSO{sub 4}{sup -}- and NO{sub 3}{sup -}- containing ions are formed by ion-molecule reactions involving OHC ions and the sulfur- and reactive nitrogen-containing molecules H{sub 2}SO{sub 4}, SO{sub 3} and NO, NO{sub 2}, HNO{sub 2}, HNO{sub 3}. (author)

  8. The main technical progress directions in air-jet engine design branch, which are worked out by the “Single theory of continuous flow propulsions”

    Directory of Open Access Journals (Sweden)

    Борис Шамшадович Мамедов

    2016-03-01

    Full Text Available The main technical progress directions in air-jet engine design branch, which are worked out by the “Single theory of continuous flow propulsions” are highlighted. They are connected with providing the fly security by air-jet engines gas-dynamic work steady increasing with full elimination zone of rigid (spring stroke in the cross section B-B of the air-jet engines, with bypass turbojet engine’s thrust increasing with simultaneously fuel consumption lowering, with inlet and outlet decibel characteristic and radial dementias lowering, with high pressure compressor’s last working wheels blades increasing, with regulating law air-jet engine’s introduction to provide maximum thrust with the purpose of flying (thrust efficiency increasing

  9. Positive ion chemistry in the exhaust plumes of an air craft jet engine and a burner: investigations with a quadrupole ion trap mass spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Kiendler, A.; Aberle, S.; Arnold, F. [Max Planck Institute for Nuclear Physics, Heidelberg (Germany). Atmospheric Physics Div.

    2000-07-01

    Using a quadrupole ion trap mass spectrometer detailed composition analyses were made of positive ions in the exhaust of an aircraft jet engine and of a jet fuel burner. For both scenarios complex organic ions with large mass numbers were most abundant. By employing the MS{sup 2}-mode of the quadrupole ion trap mass spectrometer, mass selected trapped ions were intendently broken up and characteristic fragment ions were observed. The latter indicate that the parent ions contain hydrogen, carbon and oxygen which is indicative of oxygenated hydrocarbons. This contrasts recent composition measurements of negative ions in aircraft jet engine exhaust made by our group which revealed that negative ions contain the inorganic acid H{sub 2}SO{sub 4}. Our present measurements support the view that positive ions in aircraft jet engine exhaust contain preferably organic molecules. (author)

  10. Design and Control of a Proof-of-Concept Active Jet Engine Intake Using Shape Memory Alloy Actuators

    Science.gov (United States)

    Song, Gangbing; Ma, Ning; Penney, Nicholas; Barr, Todd; Lee, Ho-Jun; Arnold, Steven M.

    2004-01-01

    The design and control of a novel proof-of-concept active jet engine intake using Nickel-Titanium (Ni-Ti or Nitinol) shape memory alloy (SMA) wire actuators is used to demonstrate the potential of an adaptive intake to improve the fuel efficiency of a jet engine. The Nitinol SMA material is selected for this research due to the material's ability to generate large strains of up to 5 percent for repeated operations, a high power-to-weight ratio, electrical resistive actuation, and easy fabrication into a variety of shapes. The proof-of-concept engine intake employs an overlapping leaf design arranged in a concentric configuration. Each leaf is mounted on a supporting bar that rotates upon actuation by SMA wires electrical resistive heating. Feedback control is enabled through the use of a laser range sensor to detect the movement of a leaf and determine the radius of the intake area. Due to the hysteresis behavior inherent in SMAs, a nonlinear robust controller is used to direct the SMA wire actuation. The controller design utilizes the sliding-mode approach to compensate for the nonlinearities associated with the SMA actuator. Feedback control experiments conducted on a fabricated proof-of-concept model have demonstrated the capability to precisely control the intake area and achieve up to a 25 percent reduction in intake area. The experiments demonstrate the feasibility of engine intake area control using the proposed design.

  11. Development and Application of A Membrane-Based Thermodenuder for Measurement of Volatile Particles Emitted by A Jet Turbine Engine

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Mengdawn [ORNL

    2010-01-01

    Measurement of volatile particles emitted by modern jet engines is a daunting task. Besides the complexity in sampling jet aircraft exhaust, the main difficulty lies at how to faithfully capture the phase-partition dynamics of volatile particles as they travel downstream from the engine exhaust nozzle. As a result, the physico-chemical properties of the exhaust are also transformed. We have developed a sampling instrument that aims at enabling study of the phase-partition dynamics. The objective of this research project was to design and evaluate a new thermodenuder for performing phase separation of the engine-emitted volatile particles. The backbone of the new thermodenuder is a thin metallic membrane. The membrane enables extraction of molecules that can be thermally desorbed from the condensed particulate phases and collected for subsequent chemical analysis. Toward realization of the technique in the future field aircraft emissions measurement we tested this new thermo-denuding device using laboratory-generated particles that were made of non-volatile or semi-volatile chemicals. The particle penetration efficiency, a measure of the device performance, of this thermodenuder was found to be better than 99%. Results obtained from the tests executed at a number of operating temperature conditions show reasonably good thermal separation. We have scheduled to apply this new device to characterize emissions from a T63 turboshaft engine in the spring of 2010 and are expecting to show the engine results at the conference. The test results based on the laboratory-generated particles were encouraging for the intended application. With excellent particle transmission efficiency and an ability to simultaneously measure the composition in the gas and particle phases of the engine particles, we believe the new technology will make a great contribution to measurement research of engine emissions.

  12. Jet-engine-based units for cleaning transport media and thawing frozen soil at mining, metallurgical, and transportation facilities

    Energy Technology Data Exchange (ETDEWEB)

    Khechuev, Y.D.

    2008-01-15

    In recent years, it has become much more difficult to deal with the adhesion and freezing of moist overburden or soil during mining and transport operations due to the increase in the volume of the various materials being mined and transported - coal, ore, fluxes, structural materials, etc. The most productive and effective methods to deal with the sticking and freezing of soil and rock are gas dynamic methods. These methods employ high-speed jets of hot gases from jet engines and can be 15-30 times more productive than mechanical methods and machinery. Proceeding on the basis of calculations, completed studies, and field tests, the Gortekhtrans Department of Research Institute for Problems of the Kursk Magnetic Anomaly (NIIKMA) has developed several highly efficient units that employ this technology.

  13. A multi-band flare in the M 87 jet 80 pc away from the central engine.

    Science.gov (United States)

    Chang, C. S.; Ros, E.; Kovalev, Y. Y.; Lister, M. L.

    The radio-loud active galactic nucleus M 87 hosts a powerful jet fueled by a super-massive black hole in its center. A bright feature 80 pc away from the central engine of M 87, namely HST-1, has shown a multi-band flare that peaked in 2005. Early radio, optical and X-ray observations have suggested that HST-1 is superluminal, and is possibly related to the TeV flare observed by HESS around 2005. Therefore, it was suggested that HST-1 has blazar-like activity. To examine the blazar-like nature for this superluminal knot in the M 87 jet, we analyzed VLBA 2 cm data of 15 epochs from 2000 to 2009. HST-1 is successfully detected with milliarcsecond resolution from 2003 to 2007, and our findings do not support that HST-1 has a blazar-like nature.

  14. J-85 jet engine noise measured in the ONERA S1 wind tunnel and extrapolated to far field

    Science.gov (United States)

    Soderman, Paul T.; Julienne, Alain; Atencio, Adolph, Jr.

    1991-01-01

    Noise from a J-85 turbojet with a conical, convergent nozzle was measured in simulated flight in the ONERA S1 Wind Tunnel. Data are presented for several flight speeds up to 130 m/sec and for radiation angles of 40 to 160 degrees relative to the upstream direction. The jet was operated with subsonic and sonic exhaust speeds. A moving microphone on a 2 m sideline was used to survey the radiated sound field in the acoustically treated, closed test section. The data were extrapolated to a 122 m sideline by means of a multiple-sideline source-location method, which was used to identify the acoustic source regions, directivity patterns, and near field effects. The source-location method is described along with its advantages and disadvantages. Results indicate that the effects of simulated flight on J-85 noise are significant. At the maximum forward speed of 130 m/sec, the peak overall sound levels in the aft quadrant were attentuated approximately 10 dB relative to sound levels of the engine operated statically. As expected, the simulated flight and static data tended to merge in the forward quadrant as the radiation angle approached 40 degrees. There is evidence that internal engine or shock noise was important in the forward quadrant. The data are compared with published predictions for flight effects on pure jet noise and internal engine noise. A new empirical prediction is presented that relates the variation of internally generated engine noise or broadband shock noise to forward speed. Measured near field noise extrapolated to far field agrees reasonably well with data from similar engines tested statically outdoors, in flyover, in a wind tunnel, and on the Bertin Aerotrain. Anomalies in the results for the forward quadrant and for angles above 140 degrees are discussed. The multiple-sideline method proved to be cumbersome in this application, and it did not resolve all of the uncertainties associated with measurements of jet noise close to the jet. The

  15. Effect of Engine Installation on Jet Noise using a Hybrid LES/RANS Approach Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Installation effects arising from propulsion airframe interaction are known to produce substantial variations in the in-situ jet noise. A hybrid LES/RANS...

  16. Linking the central engine to the jet properties in radio loud AGN

    CERN Document Server

    Olguín-Iglesias, A; Chavushyan, V; Valtaoja, E; Añorve, C; Nilsson, K; Kotilainen, J; Tornikoski, M

    2015-01-01

    We explore the connection between the black hole mass and its relativistic jet for a sample of radio-loud AGN (z < 1), in which the relativistic jet parameters are well estimated by means of long term monitoring with the 14m Mets\\"ahovi millimeter wave telescope and the Very Long Base-line Array (VLBA). NIR host galaxy images taken with the NOTCam on the Nordic Optical Telescope (NOT) and retrieved from the 2MASS all-sky survey allowed us to perform a detailed surface brightness decomposition of the host galaxies in our sample and to estimate reliable black hole masses via their bulge luminosities. We present early results on the correlations between black hole mass and the relativistic jet parameters. Our preliminary results suggest that the more massive the black hole is, the faster and the more luminous jet it produces.

  17. Transport of exhaust products in the near trail of a jet engine under atmospheric conditions

    Energy Technology Data Exchange (ETDEWEB)

    Karcher, B. [Universitat Muenchen, Freising (Germany)

    1994-07-01

    The transport of exhaust effluents and the possibility of water ice contrail formation are investigated under the specific fluid dynamical conditions in the near exhaust trail of a subsonic jet aircraft at cruise altitude. By means of a computational model describing the two-dimensional turbulent mixing of a single jet of hot exhaust gas with the atmosphere, representative results are discussed on the temperature and saturation ratio evolutions of air parcels in the jet flow field as well as on radial distributions of exhaust effluents undergoing chemical reactions behind the nozzle exit with prescribed, typical net reaction rates. The results underline the importance of a simultaneous treatment of spatially resolved jet expansion together with microphysical and chemical processes, because this coupling leads to distinct concentration patterns for various classes of chemical reactants and is essential for the detailed prediction of contrails.

  18. Linking the central engine to the jet properties in radio loud AGN

    Science.gov (United States)

    Olguín-Iglesias, A.; León-Tavares, J.; Chavushyan, V.; Valtaoja, E.; Añorve, C.; Nilsson, K.; Kotilainen, J.; Tornikoski, M.

    2015-03-01

    We explore the connection between the black hole mass and its relativistic jet for a sample of radio-loud AGN (z < 1), in which the relativistic jet parameters are well estimated by means of long term monitoring with the 14m Metsähovi millimeter wave telescope and the Very Long Base-line Array (VLBA). NIR host galaxy images taken with the NOTCam on the Nordic Optical Telescope (NOT) and retrieved from the 2MASS all-sky survey allowed us to perform a detailed surface brightness decomposition of the host galaxies in our sample and to estimate reliable black hole masses via their bulge luminosities. We present early results on the correlations between black hole mass and the relativistic jet parameters. Our preliminary results suggest that the more massive the black hole is, the faster and the more luminous jet it produces.

  19. Engine jet entrainment in the near field of an aircraft; Entrainement du jet d`un reacteur dans le champ aerodynamique proche d`un avion

    Energy Technology Data Exchange (ETDEWEB)

    Garnier, F.; Jacquin, L.; Laverdant, A.

    1997-12-31

    A simplified approach has been applied to analyse the mixing and entrainment processes of the engine exhaust through their interaction with the vortex wake of an aircraft. Our investigation is focused on the near field, extending from exit nozzle to the beginning of the vortex phase (i.e. to about twenty seconds after the wake is generated). This study is performed using an integral model and a numerical simulation for a two engine large civil aircraft. The properties of the wing-tip vortices on the calculation of the dilution ratio (defined as a tracer concentration) have been shown. The mixing process is also affected by the buoyancy effect, but only after the jet regime, when the trapping in the vortex core has occurred. Qualitative comparison with contrail photography shows similar features. Finally the distortion and stretching of the plume streamlines inside the vortices can be observed, and the role of the descent of the vortices on the maximum tracer concentration has been discussed. (author) 19 refs.

  20. Noise data for a twin-engine commercial jet aircraft flying conventional, steep, and two-segment approaches

    Science.gov (United States)

    Hastings, E. C., Jr.; Mueller, A. W.; Hamilton, J. R.

    1977-01-01

    Center-line noise measurements of a twin-engine commercial jet aircraft were made during steep landing approach profiles, and during two-segment approach profiles for comparison with similar measurements made during conventional approaches. The steep and two-segment approaches showed significant noise reductions when compared with the -3 deg base line. The measured noise data were also used to develop a method for estimating the noise under the test aircraft at thrust and altitude conditions typical of current landing procedures and of landing procedures under development for the Advanced Air Traffic Control System.

  1. Hygroscopic properties of jet engine combustor particles during the hot-end simulator (HES) PartEmis campaign

    Energy Technology Data Exchange (ETDEWEB)

    Gysel, M.; Nyeki, S.; Weingartner, E.; Baltensperger, U.; Petzold, A.; Wilson, C.W.

    2003-03-01

    The influence of the turbine section of a jet engine on particle properties was investigated by means of a hot end simulator (HES) during the EC project PartEmis. Hygroscopic growth factors were measured using a Hygroscopicity Tandem Differential Mobility Analyser (H-TDMA). The results suggest a slight in-crease of particle hygroscopicity through the HES, but the main particle features are determined at the combustor exit already, i.e. particle hygroscopicity increases with increasing fuel sulphur content (FSC). (author)

  2. The methodology of variable management of propellant fuel consumption by jet-propulsion engines of a spacecraft

    Science.gov (United States)

    Kovtun, V. S.

    2012-12-01

    Traditionally, management of propellant fuel consumption on board of a spacecraft is only associated with the operation of jet-propulsion engines (JPE) that are actuator devices of motion control systems (MCS). The efficiency of propellant fuel consumption depends not only on the operation of the MCS, but also, to one extent or another, on all systems functioning on board of a spacecraft, and on processes that occur in them and involve conversion of variable management of propellant fuel consumption by JPEs as a constituent part of the control of the complex process of spacecraft flight.

  3. A study to estimate and compare the total particulate matter emission indices (EIN) between traditional jet fuel and two blends of Jet A/Camelina biofuel used in a high by-pass turbofan engine: A case study of Honeywell TFE-109 engine

    Science.gov (United States)

    Shila, Jacob Joshua Howard

    The aviation industry is expected to grow at an annual rate of 5% until the year 2031 according to Boeing Outlook Report of 2012. Although the aerospace manufacturers have introduced new aircraft and engines technologies to reduce the emissions generated by aircraft engines, about 15% of all aircraft in 2032 will be using the older technologies. Therefore, agencies such as the National Aeronautics and Astronautics Administration (NASA), Federal Aviation Administration (FAA), the Environmental Protection Agency (EPA) among others together with some academic institutions have been working to characterize both physical and chemical characteristics of the aircraft particulate matter emissions to further understand their effects to the environment. The International Civil Aviation Organization (ICAO) is also working to establish an inventory with Particulate Matter emissions for all the aircraft turbine engines for certification purposes. This steps comes as a result of smoke measurements not being sufficient to provide detailed information on the effects of Particulate Matter (PM) emissions as far as the health and environmental concerns. The use of alternative fuels is essential to reduce the impacts of emissions released by Jet engines since alternative aviation fuels have been studied to lower particulate matter emissions in some types of engines families. The purpose of this study was to determine whether the emission indices of the biofuel blended fuels were lower than the emission indices of the traditional jet fuel at selected engine thrust settings. The biofuel blends observed were 75% Jet A-25% Camelina blend biofuel, and 50% Jet A-50% Jet A blend biofuel. The traditional jet fuel in this study was the Jet A fuel. The results of this study may be useful in establishing a baseline for aircraft engines' PM inventory. Currently the International Civil Aviation Organization (ICAO) engines emissions database contains only gaseous emissions data for only the TFE 731

  4. Transient combustion process of an IDI diesel engine with dual-throat jet at cold-starting

    Energy Technology Data Exchange (ETDEWEB)

    Li, D.; Zhu, X.; He, X.; Peng, L.

    1996-09-01

    The dual-throat jet technique has been successfully used to improve cold-starting of the swirl-type IDI diesel engines. It has been proven that, with the aid of the second throat connecting the swirl chamber and the main combustion chamber, the cold-starting process was more stable, quieter and cleaner. An intensive fundamental experimental investigation of the transient process of the ignition and combustion at cold-starting has-been conducted on a swirl-chamber IDI diesel engine with the help of high-speed photography. Based on the results of this investigation, the following conclusions have been made: (1) there exist three types of heat release rate pattern at the cold-starting, different patterns will result in different engine behavior; (2) the secondary throat has two effects on the engine starting characteristics: (a) improvement of the ignition conditions in the main chamber by directly delivering pilot fuel; (b) improvement of the fuel/air mixing process by intensifying turbulence in the swirl chamber, which depends on the geometrical shape and orientation of the throat; (3) the counter stream of air against the fuel spray accelerates dispersion and atomization of the fuel spray in the swirl chamber. It plays the primary role in assisting the cold starting of the engine.

  5. Spectroscopic support of laser remote sensing of the sulfur dioxide gas in the jet of engine exhaust gases

    Science.gov (United States)

    Voitsekhovskaya, O. K.; Kashirskii, D. E.; Egorov, O. V.

    2013-09-01

    The feasibility of SO2 registration in the plume of a jet engine as one of the methods of monitoring of its operation quality is investigated. Spectral characteristics are calculated using the line by line method, information-computing complex TRAVA developed by the authors, and the compiled spectroscopic database on high-temperature SO2. Unlike the HITRAN database, the original spectroscopic data possess predictability up to T = 1500 K. It is established that in case of active SO2 detection using a CO laser, the laser line corresponding to the 32-31 Р5 transition is promising for temperatures T = 300-1100 K. In addition, the most suitable range of the spectrum for passive sensing of hot SO2 in the engine plume - 1330.0-1331.6 cm-1 - is established in which the useful signal level exceeds background radiation for a minimum SO2 concentration (5 ppm).

  6. Low-Boom and Low-Drag Optimization of the Twin Engine Version of Silent Supersonic Business Jet

    Science.gov (United States)

    Sato, Koma; Kumano, Takayasu; Yonezawa, Masahito; Yamashita, Hiroshi; Jeong, Shinkyu; Obayashi, Shigeru

    Multi-Objective Optimization has been applied to a design problem of the twin engine concept for Silent Supersonic Business Jet (SSBJ). This problem aims to find main wing, body, tail wing and engine nacelle configurations, which can minimize both sonic boom and drag in a supersonic cruising flight. The multi-objective genetic algorithm (MOGA) coupled with the Kriging model has been used to globally and effectively search for optimal design candidates in the multi-objective problem. The drag and the sonic boom have been evaluated by the computational fluid dynamics (CFD) simulation and the waveform parameter method. As a result, the present optimization has successfully obtained low-boom and low-drag design candidates, which are better than the baseline design by more than 40% regarding each performance. Moreover, the structure of design space has been visualized by the self-organizing map (SOM).

  7. Low cycle fatigue numerical estimation of a high pressure turbine disc for the AL-31F jet engine

    Directory of Open Access Journals (Sweden)

    Spodniak Miroslav

    2017-01-01

    Full Text Available This article deals with the description of an approximate numerical estimation approach of a low cycle fatigue of a high pressure turbine disc for the AL-31F turbofan jet engine. The numerical estimation is based on the finite element method carried out in the SolidWorks software. The low cycle fatigue assessment of a high pressure turbine disc was carried out on the basis of dimensional, shape and material disc characteristics, which are available for the particular high pressure engine turbine. The method described here enables relatively fast setting of economically feasible low cycle fatigue of the assessed high pressure turbine disc using a commercially available software. The numerical estimation of accuracy of a low cycle fatigue depends on the accuracy of required input data for the particular investigated object.

  8. Low cycle fatigue numerical estimation of a high pressure turbine disc for the AL-31F jet engine

    Science.gov (United States)

    Spodniak, Miroslav; Klimko, Marek; Hocko, Marián; Žitek, Pavel

    This article deals with the description of an approximate numerical estimation approach of a low cycle fatigue of a high pressure turbine disc for the AL-31F turbofan jet engine. The numerical estimation is based on the finite element method carried out in the SolidWorks software. The low cycle fatigue assessment of a high pressure turbine disc was carried out on the basis of dimensional, shape and material disc characteristics, which are available for the particular high pressure engine turbine. The method described here enables relatively fast setting of economically feasible low cycle fatigue of the assessed high pressure turbine disc using a commercially available software. The numerical estimation of accuracy of a low cycle fatigue depends on the accuracy of required input data for the particular investigated object.

  9. Numerical laser beam propagation using a Large Eddy Simulation refractive index field representing a jet engine exhaust

    Science.gov (United States)

    Sjöqvist, Lars; Henriksson, Markus; Fedina, Ekaterina; Fureby, Christer

    2010-10-01

    The exhaust from jet engines introduces extreme turbulence levels in local environments around aircrafts. This may degrade the performance of electro-optical missile warning and laser-based DIRCM systems used to protect aircrafts against heat-seeking missiles. Full scale trials using real engines are expensive and difficult to perform motivating numerical simulations of the turbulence properties within the jet engine exhaust. Large Eddy Simulations (LES) is a computational fluid dynamics method that can be used to calculate spatial and temporal refractive index dynamics of the turbulent flow in the engine exhaust. From LES simulations the instantaneous refractive index in each grid point can be derived and interpolated to phase screens for numerical laser beam propagation or used to estimate aberration effects from optical path differences. The high computation load of LES limits the available data in terms of the computational volume and number of time steps. In addition the phase screen method used in laser beam propagation may also be too slow. For this reason extraction of statistical parameters from the turbulence field and statistical beam propagation methods are studied. The temporal variation of the refractive index is used to define a spatially varying structure constant. Ray-tracing through the mean refractive index field provides integrated static aberrations and the path integrated structure constant. These parameters can be used in classical statistical parameterised models describing propagation through turbulence. One disadvantage of using the structure constant description is that the temporal information is lost. Methods for studying the variation of optical aberrations based on models of Zernike coefficients are discussed. The results of the propagation calculations using the different methods are compared to each other and to available experimental data. Advantages and disadvantages of the different methods are briefly discussed.

  10. Comparison of PM emissions from a commercial jet engine burning conventional, biomass, and Fischer-Tropsch fuels.

    Science.gov (United States)

    Lobo, Prem; Hagen, Donald E; Whitefield, Philip D

    2011-12-15

    Rising fuel costs, an increasing desire to enhance security of energy supply, and potential environmental benefits have driven research into alternative renewable fuels for commercial aviation applications. This paper reports the results of the first measurements of particulate matter (PM) emissions from a CFM56-7B commercial jet engine burning conventional and alternative biomass- and, Fischer-Tropsch (F-T)-based fuels. PM emissions reductions are observed with all fuels and blends when compared to the emissions from a reference conventional fuel, Jet A1, and are attributed to fuel properties associated with the fuels and blends studied. Although the alternative fuel candidates studied in this campaign offer the potential for large PM emissions reductions, with the exception of the 50% blend of F-T fuel, they do not meet current standards for aviation fuel and thus cannot be considered as certified replacement fuels. Over the ICAO Landing Takeoff Cycle, which is intended to simulate aircraft engine operations that affect local air quality, the overall PM number-based emissions for the 50% blend of F-T fuel were reduced by 34 ± 7%, and the mass-based emissions were reduced by 39 ± 7%.

  11. Condensation of water vapor and carbon dioxide in the jet exhausts of rocket engines: 1. Heterogeneous condensation of combustion products

    Science.gov (United States)

    Platov, Yu. V.; Semenov, A. I.; Filippov, B. V.

    2014-01-01

    Condensation of water vapor and carbon dioxide in the jet exhausts of rocket engines during last stages of Proton, Molniya, and Start launchers operating in the upper atmospheric with different types of fuels is considered. Particle heating is taken into account with emission of latent heat of condensation and energy loss due to radiation and heat exchange with combustion products. Using the solution of the heat balance and condensed particle mass equations, the temporal change in the temperature and thickness of the condensate layer is obtained. Practically, no condensation of water vapor and carbon dioxide in the jet exhaust of a Start launcher occurs. In plumes of Proton and Molniya launchers, the condensation of water vapor and carbon dioxide can start at distances of 120-170 m and 450-650 m from the engine nozzle, respectively. In the course of condensation, the thickness of the "water" layer on particles can exceed 100 Å, and the thickness of carbon dioxide can exceed 60 Å.

  12. DBD Plasma Actuators for Flow Control in Air Vehicles and Jet Engines - Simulation of Flight Conditions in Test Chambers by Density Matching

    Science.gov (United States)

    Ashpis, David E.; Thurman, Douglas R.

    2011-01-01

    Dielectric Barrier Discharge (DBD) Plasma actuators for active flow control in aircraft and jet engines need to be tested in the laboratory to characterize their performance at flight operating conditions. DBD plasma actuators generate a wall-jet electronically by creating weakly ionized plasma, therefore their performance is affected by gas discharge properties, which, in turn, depend on the pressure and temperature at the actuator placement location. Characterization of actuators is initially performed in a laboratory chamber without external flow. The pressure and temperature at the actuator flight operation conditions need to be simultaneously set in the chamber. A simplified approach is desired. It is assumed that the plasma discharge depends only on the gas density, while other temperature effects are assumed to be negligible. Therefore, tests can be performed at room temperature with chamber pressure set to yield the same density as in operating flight conditions. The needed chamber pressures are shown for altitude flight of an air vehicle and for jet engines at sea-level takeoff and altitude cruise conditions. Atmospheric flight conditions are calculated from standard atmosphere with and without shock waves. The engine data was obtained from four generic engine models; 300-, 150-, and 50-passenger (PAX) aircraft engines, and a military jet-fighter engine. The static and total pressure, temperature, and density distributions along the engine were calculated for sea-level takeoff and for altitude cruise conditions. The corresponding chamber pressures needed to test the actuators were calculated. The results show that, to simulate engine component flows at in-flight conditions, plasma actuator should be tested over a wide range of pressures. For the four model engines the range is from 12.4 to 0.03 atm, depending on the placement of the actuator in the engine. For example, if a DBD plasma actuator is to be placed at the compressor exit of a 300 PAX engine, it

  13. Bioprinting by laser-induced forward transfer for tissue engineering applications: jet formation modeling

    Energy Technology Data Exchange (ETDEWEB)

    Mezel, C; Hallo, L [Centre Lasers Intenses et Applications, UMR 5107 Universite Bordeaux 1-CNRS-CEA, 33405 Talence, Cedex (France); Souquet, A; Guillemot, F, E-mail: mezel@celia.u-bordeaux1.f [Institut National de la Sante et de la Recherche Medicale, Universite Bordeaux 2 - UMR 577, 146 Rue Leo Saignat, 33076 Bordeaux Cedex (France)

    2010-03-15

    In this paper, a nanosecond LIFT process is analyzed both from experimental and modeling points of view. Experimental results are first presented and compared to simple estimates obtained from physical analysis, i.e. energy balance, jump relations and analytical pocket dynamics. Then a self-consistent 2D axisymmetric modeling strategy is presented. It is shown that data accessible from experiments, i.e. jet diameter and velocity, can be reproduced. Moreover, some specific mechanisms involved in the rear-surface deformation and jet formation may be described by some scales of hydrodynamic process, i.e. shock waves propagation and expansion waves, as a consequence of the laser heating. It shows that the LIFT process is essentially driven by hydrodynamics and thermal transfer, and that a coupled approach including self-consistent laser energy deposition, heating by thermal conduction and specific models for matter is required.

  14. Bioprinting by laser-induced forward transfer for tissue engineering applications: jet formation modeling.

    Science.gov (United States)

    Mézel, C; Souquet, A; Hallo, L; Guillemot, F

    2010-03-01

    In this paper, a nanosecond LIFT process is analyzed both from experimental and modeling points of view. Experimental results are first presented and compared to simple estimates obtained from physical analysis, i.e. energy balance, jump relations and analytical pocket dynamics. Then a self-consistent 2D axisymmetric modeling strategy is presented. It is shown that data accessible from experiments, i.e. jet diameter and velocity, can be reproduced. Moreover, some specific mechanisms involved in the rear-surface deformation and jet formation may be described by some scales of hydrodynamic process, i.e. shock waves propagation and expansion waves, as a consequence of the laser heating. It shows that the LIFT process is essentially driven by hydrodynamics and thermal transfer, and that a coupled approach including self-consistent laser energy deposition, heating by thermal conduction and specific models for matter is required.

  15. VSOP-2 : a space VLBI mission to image central engines and jet launching regions

    Science.gov (United States)

    Kameno, Seiji; Tsuboi, Masato; Murata, Yasuhiro; Doi, Akihiro; Asaki, Yoshiharu; Mochizuki, Nanako; Hagiwara, Yoshi-Aki; Kino, Motoki; Nagai, Hiroshi; Asada, Keiichi; Inoue, Makoto; Sudou, Hiroshi; Sawada-Satoh, Satoko

    VSOP-2 is a space VLBI program using the spacecraft ASTRO-G to be launched in 2015 by the Japan Aerospace eXploration Agency. The array consisting of a 9-m antenna in orbit and ground radio telescopes offers angular resolutions of 40, 80, and 210 microarcsec at 43, 22, and 8 GHz, respectively. The resolution allows us to image accretion disks and jet launching regions in nearby active galactic nuclei such as M 87. Dual polarization receivers enable full Stokes images at all frequency to illustrate magnetic fields in jets. Phase referencing is capable for astrometry by 60-sec-cycle switching maneuvers. Higher sensitivity than the VSOP (HALCA) is achieved by cooled receivers at 22 and 43 GHz, 1-Gbps wideband downlink, and longer coherent integration. We will introduce the mission overview, observational specifications, and key sciences of the VSOP-2. We call for community's scientific contributions to the mission.

  16. Design, fabrication, and testing of a SMA hybrid composite jet engine chevron

    Science.gov (United States)

    Turner, Travis L.; Cabell, Randolph H.; Cano, Roberto J.; Fleming, Gary A.

    2006-01-01

    Control of jet noise continues to be an important research topic. Exhaust nozzle chevrons have been shown to reduce jet noise, but parametric effects are not well understood. Additionally, thrust loss due to chevrons at cruise suggests significant benefit from deployable chevrons. The focus of this study is development of an active chevron concept for the primary purpose of parametric studies for jet noise reduction in the laboratory and technology development to leverage for full scale systems. The active chevron concept employed in this work consists of a laminated composite structure with embedded shape memory alloy (SMA) actuators, termed a SMA hybrid composite (SMAHC). The actuators are embedded on one side of the middle surface such that thermal excitation generates a moment and deflects the structure. A brief description of the chevron design is given followed by details of the fabrication approach. Results from bench top tests are presented and correlated with numerical predictions from a model for such structures that was recently implemented in MSC.Nastran and ABAQUS. Excellent performance and agreement with predictions is demonstrated. Results from tests in a representative flow environment are also presented. Excellent performance is again achieved for both open- and closed-loop tests, the latter demonstrating control to a specified immersion into the flow. The actuation authority and immersion performance is shown to be relatively insensitive to nozzle pressure ratio (NPR). Very repeatable immersion control with modest power requirements is demonstrated.

  17. NO{sub x} removal in jet-engine exhaust: Proposed non-thermal plasma systems and economic considerations

    Energy Technology Data Exchange (ETDEWEB)

    Rosocha, L.A.; Chang, J.S.; Urashima, K.; Kim, S.J.; Miziolek, A.W.; Nusca, M.J.; Daniel, R.G.; Huie, R.F.; Herron, J.T.

    1999-07-01

    Incentives for implementing new pollution-control technologies are both regulatory and economic. Given considerable regulatory pressure, e.g., the promulgation of a NESHAPS (National Emissions Standard for hazardous Air Pollutants ) for NO{sub x} emissions in CY 2000, new de-NO{sub x} technologies are being explored. One major reason for this is that conventional de-NO{sub x} methods (like wet scrubbers plus Selective Catalytic Reduction - SCR) will not work effectively for the low NO concentrations (e.g., <50 ppm), high exhaust-gas flow rates ({approximately} 10{sup 6}Nm{sup 3}/h), and low gas temperatures (near ambient) characteristic of Jet Engine Test Cells (JETCs). The project is currently evaluating nonthermal plasma (NTP) technologies for treating jet-engine exhaust and other hazardous air pollutants. In this paper, the authors will present the initial design options for NTP reactor systems for a field-pilot demonstration on small jet engines (e.g., F107 or F112; flow rates {approximately} 10{sup 4} Nm{sup 3}/h). The field-pilot demonstration is necessary to provide further data and operating experience to more fully evaluate economic and performance projections for NTP de-NO{sub x} technology and to design larger systems with confidence. They are presently considering five candidate NTP reactor systems: pulsed corona, dielectric barrier (silent discharge), hybrid NTP reactor-adsorber, plasma-catalytic hybrid, and corona radical shower. Because of the cost and logistics of using an electron-beam NTP reactor (for which some economic data will be given), they have limited the candidate systems to those based on electric-discharge-driven NTP reactors. This paper will discuss the exhaust stream to be addressed, the test setup, candidate reactor systems, and projected operating parameters and specifications for the field-pilot units--as well as initial cost comparisons of three NTP-based de-NO{sub x} systems with two SCR-based systems based on published small

  18. Minority University System Engineering: A Small Satellite Design Experience Held at the Jet Propulsion Laboratory During the Summer of 1996

    Science.gov (United States)

    Ordaz, Miguel Angel

    1997-01-01

    The University of Texas at El Paso (UTEP) in conjunction with the Jet Propulsion Laboratory (JPL), North Carolina A&T and California State University of Los Angeles participated during the summer of 1996 in a prototype program known as Minority University Systems Engineering (MUSE). The program consisted of a ten week internship at JPL for students and professors of the three universities. The purpose of MUSE as set forth in the MUSE program review August 5, 1996 was for the participants to gain experience in the following areas: 1) Gain experience in a multi-disciplinary project; 2) Gain experience working in a culturally diverse atmosphere; 3) Provide field experience for students to reinforce book learning; and 4) Streamline the design process in two areas: make it more financially feasible; and make it faster.

  19. ON THE POSSIBILITY OF BURNING ACCELERATION IN THE COMBUSTION CHAMBERS OF ADVANCED JET ENGINES BY DEEPLY SUBCRITICAL MICROWAVE DISCHARGE

    Directory of Open Access Journals (Sweden)

    P. V. Bulat

    2016-03-01

    Full Text Available The paper deals with the problem of increasing the speed of propagation of the flame front as applied to the problems of reducing noxious emissions of nitrogen oxides formed during operation of jet engines and industrial turbines, as well as the stabilization of a supersonic combustion. We investigate the possibility of reducing the induction time using non-equilibrium cold plasma produced by an electromagnetic vibrator in beam quasi-optical MW radiation. The positive effect of cold non-equilibrium plasma on increasing the rate of occurrence of oxidation reactions in the air is well known and undisputed. The presented results of the experiments demonstrate the advantage of the method developed in terms of efficiency and suppression of nitrogen oxide emissions. Also they show that combustion stabilization is achieved similarly in a supersonic flow.

  20. Vehicle implementation and cold start calibration of a port injected M100 engine using plasma jet ignition and prompt EGR

    Energy Technology Data Exchange (ETDEWEB)

    Gardiner, D.P.; Mallory, R.W.; Rao, V.K.; Bardon, M.F.; Battista, V.

    1995-12-31

    This paper describes the vehicle implementation and cold start calibration of a neat methanol (M100) fueled port injected engine equipped with plasma jet ignition and prompt exhaust gas recirculation. Test results are presented in which the influence of various factors on fuel enrichment requirements were studied with the aim of identifying strategies to reduce enrichment and lower start-up emissions. Vehicle cold starting has been demonstrated down to {minus}30 C and studied in detail circa {minus}20 C. Reductions in start-up CO emissions at {minus}7 C have been achieved by means of early closed loop fuel control. Experimental results are also presented which indicate that the potential exists to reduce start-up hydrocarbon emissions at 25 C when appropriate calibration strategies are employed.

  1. First composition measurements of positive chemiions in aircraft jet engine exhaust: detection of numerous ion species containing organic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Kiendler, A.; Arnold, F. [Max Planck Institute for Nuclear Physics, Heidelberg (Germany). Atmospheric Physics Division

    2002-06-01

    First mass-spectrometric composition measurements with high mass resolution of positive chemiions (CI) were made in the exhaust of an aircraft jet engine at ground level. The ion mass spectrometer used was a quadrupole ion-trap mass spectrometer with a high mass resolution and a large mass range (up to 2000 atomic mass units (amu)). The mass spectrum which extends from 150 to 2000 amu is very crowded showing a mass peak at nearly every mass number m. CI with odd m are much more abundant than CI with even m. Groups of mass peaks separated by 14 amu are clearly noticeable indicating CH{sub 2} groups. Probably many of the observed positive CI are protonated massive volatile organic compounds (VOCs). Some of the observed positive CI may also be cluster ions composed of VOCs. (author)

  2. Use of a Ni60Ti shape memory alloy for active jet engine chevron application: II. Experimentally validated numerical analysis

    Science.gov (United States)

    Hartl, D. J.; Mooney, J. T.; Lagoudas, D. C.; Calkins, F. T.; Mabe, J. H.

    2010-01-01

    A shape memory alloy (SMA) composition of Ni60Ti40 (wt%) was chosen for the fabrication of active beam components used as cyclic actuators and incorporated into morphing aerospace structures. The active structure is a variable-geometry chevron (VGC) designed to reduce jet engine noise in the take-off flight regime while maintaining efficiency in the cruise regime. This two-part work addresses the training, characterization and derived material properties of the new nickel-rich NiTi composition, the assessment of the actuation properties of the active beam actuator and the accurate analysis of the VGC and its subcomponents using a model calibrated from the material characterization. The second part of this two-part work focuses on the numerical modeling of the jet engine chevron application, where the end goal is the accurate prediction of the VGC actuation response. A three-dimensional (3D) thermomechanical constitutive model is used for the analysis and is calibrated using the axial testing results from part I. To best capture the material response, features of several SMA constitutive models proposed in the literature are combined to form a new model that accounts for two material behaviors not previously addressed simultaneously. These are the variation in the generated maximum actuation strain with applied stress level and a smooth strain-temperature constitutive response at the beginning and end of transformation. The accuracy of the modeling effort is assessed by comparing the analysis deflection predictions for a given loading path imposed on the VGC or its subcomponents to independently obtained experimental results consisting of photogrammetric data. For the case of full actuation of the assembled VGC, the average error in predicted centerline deflection is less than 6%.

  3. The outlook for application of powerful nuclear thermionic reactor - powered space electric jet propulsion engines

    Energy Technology Data Exchange (ETDEWEB)

    Semyonov, Y.P.; Bakanov, Y.A.; Synyavsky, V.V.; Yuditsky, V.D. [Rocket-Space Corp. `Energia`, Moscow (Russian Federation)

    1997-12-31

    This paper summarizes main study results for application of powerful space electric jet propulsion unit (EJPUs) which is powered by Nuclear Thermionic Power Unit (NTPU). They are combined in Nuclear Power/Propulsion Unit (NPPU) which serves as means of spacecraft equipment power supply and spacecraft movement. Problems the paper deals with are the following: information satellites delivery and their on-orbit power supply during 10-15 years, removal of especially hazardous nuclear wastes, mining of asteroid resources and others. Evaluations on power/time/mass relationship for this type of mission are given. EJPU parameters are compatible with Russian existent or being under development launch vehicle. (author)

  4. Experimental Study of Twin Pulse Jet Engines for Power Plant Application

    Institute of Scientific and Technical Information of China (English)

    Toshihiro Nakano; Shigeru Matsuo; Toshiaki Setoguchi; Shen Yu

    2003-01-01

    The total efficiency of power plants depends on the energy conversion in a combustor and a turbine. Considerably higher energy transfer rates can be obtained from a pulsed combustion, but unsteady flow of a single jet combustor reduces the turbine efficiency.Therefore, two pulse combustors were set in parallel and connected to a settling chamber that supplies a flow with constant pressure to the turbine.The aim of investigations presented here is a demonstration of technical feasibility for industrial applications and to show the benefits obtained from the pulse combustors.

  5. Detailed Post-Soft Impact Progressive Damage Assessment for Hybrid Structure Jet Engines

    Science.gov (United States)

    Siddens, Aaron; Bayandor, Javid; Celestina, Mark L.

    2014-01-01

    Currently, certification of engine designs for resistance to bird strike is reliant on physical tests. Predictive modeling of engine structural damage has mostly been limited to evaluation of individual forward section components, such as fan blades within a fixed frame of reference, to direct impact with a bird. Such models must be extended to include interactions among engine components under operating conditions to evaluate the full extent of engine damage. This paper presents the results of a study aim to develop a methodology for evaluating bird strike damage in advanced propulsion systems incorporating hybrid composite/metal structures. The initial degradation and failure of individual fan blades struck by a bird were investigated. Subsequent damage to other fan blades and engine components due to resultant violent fan assembly vibrations and fragmentation was further evaluated. Various modeling parameters for the bird and engine components were investigated to determine guidelines for accurately capturing initial damage and progressive failure of engine components. Then, a novel hybrid structure modeling approach was investigated and incorporated into the crashworthiness methodology. Such a tool is invaluable to the process of design, development, and certification of future advanced propulsion systems.

  6. Binary Neutron Star Mergers: A Jet Engine for Short Gamma-Ray Bursts

    Science.gov (United States)

    Ruiz, Milton; Lang, Ryan N.; Paschalidis, Vasileios; Shapiro, Stuart L.

    2016-06-01

    We perform magnetohydrodynamic simulations in full general relativity (GRMHD) of quasi-circular, equal-mass, binary neutron stars that undergo merger. The initial stars are irrotational, n = 1 polytropes and are magnetized. We explore two types of magnetic-field geometries: one where each star is endowed with a dipole magnetic field extending from the interior into the exterior, as in a pulsar, and the other where the dipole field is initially confined to the interior. In both cases the adopted magnetic fields are initially dynamically unimportant. The merger outcome is a hypermassive neutron star that undergoes delayed collapse to a black hole (spin parameter a/M BH ˜ 0.74) immersed in a magnetized accretion disk. About 4000M ˜ 60(M NS/1.625 M ⊙) ms following merger, the region above the black hole poles becomes strongly magnetized, and a collimated, mildly relativistic outflow—an incipient jet—is launched. The lifetime of the accretion disk, which likely equals the lifetime of the jet, is Δ t ˜ 0.1 (M NS/1.625 M ⊙) s. In contrast to black hole-neutron star mergers, we find that incipient jets are launched even when the initial magnetic field is confined to the interior of the stars.

  7. Catalytic microtubular jet engines self-propelled by accumulated gas bubbles.

    Science.gov (United States)

    Solovev, Alexander A; Mei, Yongfeng; Bermúdez Ureña, Esteban; Huang, Gaoshan; Schmidt, Oliver G

    2009-07-01

    Strain-engineered microtubes with an inner catalytic surface serve as self-propelled microjet engines with speeds of up to approximately 2 mm s(-1) (approximately 50 body lengths per second). The motion of the microjets is caused by gas bubbles ejecting from one opening of the tube, and the velocity can be well approximated by the product of the bubble radius and the bubble ejection frequency. Trajectories of various different geometries are well visualized by long microbubble tails. If a magnetic layer is integrated into the wall of the microjet engine, we can control and localize the trajectories by applying external rotating magnetic fields. Fluid (i.e., fuel) pumping through the microtubes is revealed and directly clarifies the working principle of the catalytic microjet engines.

  8. High performance jet-engine flight test data base for HSR

    Science.gov (United States)

    Kelly, Jeffrey

    1992-01-01

    The primary acoustic priority of the flight test data base for HSR is the validation of the NASA Aircraft Noise Prediction Program (ANOPP) and other source noise codes. Also, the noise measurements are an important support function for the High Lift Program devoted to HSR. Another concern that will be addressed is a possible noise problem 7-20 miles from take-off during climbout. The attention arises from the higher speeds envisioned for the HSCT compared to conventional aircraft causing levels to increase because of Doppler amplification in conjunction with high source levels due to jet noise. An attempt may be made to measure airframe noise for the F-16XL test which would provide an assessment of this noise component for delta wing aircraft.

  9. Understanding and overcoming scene-change artifacts in imaging Fourier-transform spectroscopy of turbulent jet engine exhaust

    Science.gov (United States)

    Tremblay, Pierre; Gross, Kevin C.; Farley, Vincent; Chamberland, Martin; Villemaire, André; Perram, Glen P.

    2009-08-01

    Jet engine exhaust radiates strongly in the midwave infrared due to line emission from combustion byproducts such as CO2, CO, and H2O. Imaging Fourier-transform spectrometers (IFTS) have the potential to measure spatial variations in plume temperature and density. However, the turbulent flow yields rapid, stochastic fluctuations in radiance during interferometric measurements which corrupt corresponding spectra. A novel, statistics-based method of interpreting a time-sequence of interferograms collected from a stochastic blackbody source is presented which enables good estimation of the underlying temperature distribution. It is shown that the median (and various other quantiles) interferograms afford unbiased spectral estimates of temperature upon Fourier transformation, in contrast to temperature estimates based on spectra obtained from mean interferograms. This method is then applied to IFTS data (200×64 pixels at 1cm-1 resolution) of a turbulent exhaust plume from a small turbojet engine. Spatial maps of brightness temperature and estimates of turbulence-induced temperature distribution are presented.

  10. Application of a production line phosphorescence sensor coating system on a jet engine for surface temperature detection

    Science.gov (United States)

    Sollazzo, P. Y.; Feist, J. P.; Berthier, S.; Charnley, B.; Wells, J.; Heyes, A. L.

    2013-09-01

    Thermal Barrier Coatings (TBC) are used to reduce the working temperature of the high pressure turbine blade metal surface and hence permit engines to operate at higher temperatures/ efficiencies. A sensor TBC is an adaptation of existing TBCs to enhance their functionality, such that they become sensors and allow measurement of component temperatures. The sensing capability is introduced by embedding optically active materials into the TBC and by illuminating these coatings with excitation light phosphorescence can be observed. The phosphorescence carries temperature and structural information about the coating. This paper describes the first ever implementation of a sensor coating system on a full-scale jet engine. The system consists of three main components: industrially manufactured coatings, advanced remote detection optics with large stand-off distances and tailored control and readout software. The majority of coatings were based on yttrium stabilized zirconia doped with Dy and Eu, although other coatings were manufactured, too. Coatings were produced on a production line using atmospheric plasma spraying. An advanced optical system was designed, manufactured and operated permitting scanning of coated components using a wide acceptance angle. Successful measurements were taken from the nozzle guide vanes at the inlet to the turbine section and are reported in the paper.

  11. Multi-Partner Experiment to Test Volcanic-Ash Ingestion by a Jet Engine

    Science.gov (United States)

    Lekki, John; Lyall, Eric; Guffanti, Marianne; Fisher, John; Erlund, Beth; Clarkson, Rory; van de Wall, Allan

    2013-01-01

    A research team of U.S. Government agencies and engine manufacturers are designing an experiment to test volcanic-ash ingestion by a NASA owned F117 engine that was donated by the U.S. Air Force. The experiment is being conducted under the auspices of NASA s Vehicle Integrated Propulsion Research (VIPR) Program and will take place in early 2014 at Edwards AFB in California as an on-ground, on-wing test. The primary objectives are to determine the effect on the engine of several hours of exposure to low to moderate ash concentrations, currently proposed at 1 and 10 mg/m3 and to evaluate the capability of engine health management technologies for detecting these effects. A natural volcanic ash will be used that is representative of distal ash clouds many 100's to approximately 1000 km from a volcanic source i.e., the ash should be composed of fresh glassy particles a few tens of microns in size. The glassy ash particles are expected to soften and become less viscous when exposed to the high temperatures of the combustion chamber, then stick to the nozzle guide vanes of the high-pressure turbine. Numerous observations and measurements of the engine s performance and degradation will be made during the course of the experiment, including borescope and tear-down inspections. While not intended to be sufficient for rigorous certification of engine performance when ash is ingested, the experiment should provide useful information to aircraft manufacturers, airline operators, and military and civil regulators in their efforts to evaluate the range of risks that ash hazards pose to aviation.

  12. Multiobjective Design Optimization of Supersonic Jet Engine in Different Cruise Mach Numbers

    Science.gov (United States)

    Ogawa, Masamichi; Sato, Tetsuya; Kobayashi, Hiroaki; Taguchi, Hideyuki

    The aim of this paper is to apply a multi-objective optimization generic algorithm (MOGA) to the conceptual design of the hypersonic/supersonic vehicles with different cruise Mach number. The pre-cooled turbojet engine is employed as a propulsion system and some engine parameters such as the precooler size, compressor size, compression ratio and fuel type are varied in the analysis. The result shows that the optimum cruise Mach number is about 4 if hydrogen fuel is used. Methane fuel instead of hydrogen reduces the vehicle gross weight by 33% in case of the Mach 2 vehicle.

  13. Trend of research and development of combustors for jet engines. Koku engine yo nenshoki no kenkyu kaihatsu doko

    Energy Technology Data Exchange (ETDEWEB)

    To, H. (Ishikawajima-Harima Heavy Industries Co. Ltd., Tokyo (Japan))

    1994-03-10

    To the aeroengine, a requirement for an improvement of the fuel consumption ratio from a viewpoint of the energy saving and for a reduction of the harmful exhaust materials from a viewpoint of environmental protection is being increasingly elevated. In order to improve a fuel consumption ratio of engine, making it a higher temperature and pressure is attempted for raising a engine cycle efficiency, and moreover there is a trend to elevate an inlet pressure and temperature of the combustor as for a combustor, and consequently an outlet temperature of the combustor becomes higher. Therefore to the combustor, a durability elongation of the liner and fuel injection valve, as well as a correspondence to a range expansion of a fuel-air ratio of the combustor are demanded. As the harmful exhaust materials, there are unburned hydrocarbon (UHC), carbon monoxides (CO), nitrogen oxides (NOx), and smoke. A reduction of NOx is most strongly requested at present. In addition to these requests on the combustor, making a study and development of the combustor more efficient is being demanded. For this purpose a numerical analysis is utilized by adapting the various purposes. As the recent utilization methods, the prediction examples of exhaust gas quantity are frequent. 14 refs., 12 figs., 1 tab.

  14. Effects of jet engine noise and performance feedback on perceived workload in a monitoring task.

    Science.gov (United States)

    Becker, A B; Warm, J S; Dember, W N; Hancock, P A

    1995-01-01

    This study examined the effects of exposure to intermittent jet aircraft noise (70 dBA or 95 dBA maximum intensity) and knowledge of results concerning signal detections (hit-KR) on performance efficiency and perceived workload in a 40-min visual vigilance task. The noise featured a Doppler-like quality in which planes seemed to approach from the monitor's left and recede to the right. Perceptual sensitivity (d') was poorer in the context of noise than in quiet but only in the presence of hit-KR. The lack of noise-related performance differences in the absence of hit-KR most likely reflected a "floor effect" rather than some special relation between noise and feedback. When compared to subjects performing in quiet, those who operated in noise were less able to profit from hit-KR, a result that may reflect the effects of noise on information processing. In addition to its negative effects on signal detectability, noise elevated the perceived workload, as measured by the NASA-TLX. This effect was robust; it was independent of the presence of hit-KR, even though hit-KR generally lowered the overall level of perceived workload. The results provide the initial experimental demonstration that perceived workload is a sensitive measure of the effects of aircraft noise in monitoring tasks.

  15. Binary neutron star mergers: a jet engine for short gamma-ray burst

    CERN Document Server

    Ruiz, Milton; Paschalidis, Vasileios; Shapiro, Stuart L

    2016-01-01

    We perform magnetohydrodynamic simulations in full general relativity (GRMHD) of quasicircular, equal-mass, binary neutron stars that undergo merger. The initial stars are irrotational, $n=1$ polytropes and are magnetized. We explore two types of magnetic-field geometries: one where each star is endowed with a dipolar magnetic field extending from the interior into the exterior, as in a pulsar, and the other where the dipolar field is initially confined to the interior. In both cases the adopted magnetic fields are dynamically unimportant initially. The merger outcome is a hypermassive neutron star that undergoes delayed collapse to a black hole (spin parameter $a/M_{\\rm BH} \\sim 0.74$) immersed in a magnetized accretion disk. About $4000M \\sim 60(M_{\\rm NS}/1.625M_\\odot)$ ms following merger, the region above the black hole poles becomes strongly magnetized, and a collimated, mildly relativistic outflow --- an incipient jet --- is launched. The lifetime of the accretion disk, which likely equals the lifetime...

  16. Decision Support Model to Evaluate Methods for Reducing Air Pollution Emissions during Jet Engine Testing

    Science.gov (United States)

    1995-12-01

    Enine Control O&M CT o RD Modifications Technoloy R&D EM R&D CT Ac aEM Cost O CT Cst Cost Cost Costo (Baseli nmoe) No Change No Change High High High...intelligent person who wants to think hard and systematically about an important real problem (Kenney and Raiffa, 1993: xv). Some additional discussion of...Programs, Langley AFB VA. Personal interview. 13 April 1995. Canfield, Alan. Environmental Engineer, Applied Research Associates, Inc, Tyndall AFB FL

  17. Effect of jet engine exhaust on SOFIA straylight performance. [Stratospheric Observatory For Infrared Astronomy

    Science.gov (United States)

    St. Clair Dinger, Ann

    1993-01-01

    The Stratospheric Observatory For Infrared Astronomy (SOFIA) is being designed at NASA's Ames Research Center as a replacement for the Kuiper Airborne Observatory (KAO). A 2.5-m Nasmyth telescope will be mounted in a Boeing 747 SP and flown at 41,000 ft, above most of the H2O in the earth's atmosphere. In the original SOFIA design, the telescope is located in front of the wings, as it is in the KAO. An alternative design with the telescope placed behind the wings is being studied as part of an effort to reduce cost and weight. In this location, the emission from the engines and the hot H2O molecules in the exhaust become significant straylight sources. The engines and exhaust radiate into the telescope cavity, and illuminate the primary and tertiary mirrors at low telescope elevation angles. The APART/PADE program was used to analyze the straylight at the SOFIA focal plane as a function of wavelength and telescope elevation angle. The emission from the engines and exhaust gas is compared to that from the earth and the telescope itself. Based on the results of this analysis, the SOFIA telescope has been moved behind the wings.

  18. From Engine to Afterglow: Collapsars Naturally Produce Top-Heavy Jets and Early-Time Plateaus in Gamma Ray Burst Afterglows

    CERN Document Server

    Duffell, Paul C

    2014-01-01

    We demonstrate that the steep decay and long plateau in the early phases of gamma ray burst (GRB) afterglows are naturally produced in the collapsar model, by a means ultimately related to the dynamics of relativistic jet propagation through a massive star. We present hydrodynamical simulations which start from a collapsar engine and evolve all the way through the late afterglow phase. The resultant outflow includes a jet core which is highly relativistic after breaking out of the star, but becomes baryon-loaded and less relativistic after colliding with a massive outer shell, corresponding to mass from the stellar atmosphere of the progenitor star which became trapped in front of the jet core at breakout. The prompt emission produced before or during this collision would then have the signature of a high Lorentz factor jet, but the afterglow is produced by the amalgamated post-collision ejecta which has more inertia than the original highly relativistic jet core and thus has a delayed deceleration. This natu...

  19. Large-scale time-resolved digital particle image velocimetry (TR-DPIV) for measurement of high subsonic hot coaxial jet exhaust of a gas turbine engine

    Science.gov (United States)

    Timmerman, B. H.; Skeen, A. J.; Bryanston-Cross, P. J.; Graves, M. J.

    2009-07-01

    The development of a highly configurable triple digital particle image velocimetry (DPIV) system is described, which is capable of acquiring both continuous, statistically independent measurements at up to 14 Hz and time-resolved PIV data at MHz rates. The system was used at QinetiQ's Noise Test Facility (NTF) as part of the EU-funded CoJeN programme to obtain measurements from high subsonic (Mach <= 0.9), hot (~500 °C), large (1/10th) scale coaxial jet flows at a standoff distance of ~1 m. High-resolution time-averaged velocity and turbulence data were obtained for complete coaxial engine exhaust plumes down to 4 m (20 jet diameters) from the nozzle exit in less than 1 h. In addition, the system allowed volumetric data to be obtained, enabling fast assessment of spatial alignment of nozzle configurations. Furthermore, novel six-frame time-series data-capture is demonstrated up to 330 kHz, used to calculate time-space correlations within the exhaust, allowing for study of spatio-temporal developments in the jet, associated with jet-noise production. The highly automated system provides synchronization triggers for simultaneous acquisition from different measurement systems (e.g. LDA) and is shown to be versatile, rugged, reliable and portable, operating remotely in a hostile environment. Data are presented for three operating conditions and two nozzle geometries, providing a database to be used to validate CFD models of coaxial jet flow.

  20. Development and demonstration of a new filter system to control emissions during jet engine testing. Final report, February 1990-September 1992

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, B.W.; Van Stone, D.A.; Nelson, S.G.

    1992-10-15

    Measurable quantities of NOx, CO and small particulates are produced and are emitted into the atmosphere during the testing of aircraft engines in jet engine test cells (JETCs). These emissions have been and are a concern to the Air Force and to others who test aircraft engines. The large quantities of exhaust gases that are generated, the wide range of testing conditions that are normally employed, and the sensitivity of engines to back pressures make control difficult and the use of conventional control technologies impractical. A need exists for a simple, low-cost method to control the emissions. In a Phase I SBIR project, Sorbent Technologies Corporation (Sorbtech) explored the ability of vermiculite to reduce or capture contaminants in exhaust gas streams. During the Phase II SBIR project described in this report, Sorbtech investigated how vermiculite might be employed in a commercial system to control emissions from JETCs and how chemical additions to vermiculite might enhance its NOx-removal abilities. The objectives of the Phase II project were to develop and to demonstrate a suitable filter design involving vermiculite that will control NOx, CO, and small-particulate emissions during jet-engine testing.... Turbine engine, Particle emissions, Air pollution. NOx Emissions, Aircraft exhaust.

  1. Identifying safer anti-wear triaryl phosphate additives for jet engine lubricants.

    Science.gov (United States)

    Baker, Paul E; Cole, Toby B; Cartwright, Megan; Suzuki, Stephanie M; Thummel, Kenneth E; Lin, Yvonne S; Co, Aila L; Rettie, Allan E; Kim, Jerry H; Furlong, Clement E

    2013-03-25

    Individuals aboard jet aircraft may be exposed to potentially toxic triaryl organophosphate anti-wear lubricant additives (TAPs) that are converted by cytochromes P450 into toxic metabolites. Consequences of exposure could be reduced by using less toxic TAPs. Our goal was to determine whether an in vitro assay for inhibition of butyrylcholinesterase (BChE) by bioactivated TAPs would be predictive of inhibition of serine active-site enzymes in vivo. The in vitro assay involved TAP bioactivation with liver microsomes and NADPH, followed by incubation with human BChE and measurement of BChE activity. Of 19 TAPs tested, tert-butylated isomers produced the least BChE inhibition. To determine the relevance of these results in vivo, mice were exposed to Durad 125 (D125; a commercial mixture of TAP esters) or to TAPs demonstrating low or no BChE inhibition when assayed in vitro. Inhibition of BChE by bioactivated TAPs in vitro correlated well with inhibition of other serine active-site enzymes in vivo, with the exception of brain acetylcholinesterase and neuropathy target esterase (NTE), which were not inhibited by any TAP tested following single exposures. A recombinant catalytic domain of NTE (rNEST) exhibited classical kinetic properties of NTE. The metabolite of tri-(o-cresyl) phosphate (ToCP), 2-(o-cresyl)-4H-1,3,2-benzodioxaphosphoran-2-one (CBDP), inhibited rNEST in vitro, but with an IC(50) value almost 6-times higher than for inhibition of BChE. Physiologically-relevant concentrations of the flavonoid naringenin dramatically reduced D125 bioconversion in vitro. The in vitro assay should provide a valuable tool for prescreening candidate TAP anti-wear additives, identifying safer additives and reducing the number of animals required for in vivo toxicity testing.

  2. Engineering

    National Research Council Canada - National Science Library

    Includes papers in the following fields: Aerospace Engineering, Agricultural Engineering, Chemical Engineering, Civil Engineering, Electrical Engineering, Environmental Engineering, Industrial Engineering, Materials Engineering, Mechanical...

  3. Analysis of strain gage reliability in F-100 jet engine testing at NASA Lewis Research Center

    Science.gov (United States)

    Holanda, R.

    1983-01-01

    A reliability analysis was performed on 64 strain gage systems mounted on the 3 rotor stages of the fan of a YF-100 engine. The strain gages were used in a 65 hour fan flutter research program which included about 5 hours of blade flutter. The analysis was part of a reliability improvement program. Eighty-four percent of the strain gages survived the test and performed satisfactorily. A post test analysis determined most failure causes. Five failures were caused by open circuits, three failed gages showed elevated circuit resistance, and one gage circuit was grounded. One failure was undetermined.

  4. Jet Engine Bird Ingestion Simulations: Comparison of Rotating to Non-Rotating Fan Blades

    Science.gov (United States)

    Howard, Samuel A.; Hammer, Jeremiah T.; Carney, Kelly S.; Pereira, J. Michael

    2013-01-01

    Bird strike events in commercial airliners are a fairly common occurrence. According to data collected by the US Department of Agriculture, over 80,000 bird strikes were reported in the period 1990 to 2007 in the US alone (Ref. 1). As a result, bird ingestion is an important factor in aero engine design and FAA certification. When it comes to bird impacts on engine fan blades, the FAA requires full-scale bird ingestion tests on an engine running at full speed to pass certification requirements. These rotating tests are complex and very expensive. To reduce development costs associated with new materials for fan blades, it is desirable to develop more cost effective testing procedures than full-scale rotating engine tests for material evaluation. An impact test on a nonrotating single blade that captures most of the salient physics of the rotating test would go a long way towards enabling large numbers of evaluative material screening tests. NASA Glenn Research Center has been working to identify a static blade test procedure that would be effective at reproducing similar results as seen in rotating tests. The current effort compares analytical simulations of a bird strike on various non-rotating blades to a bird strike simulation on a rotating blade as a baseline case. Several different concepts for simulating the rotating loads on a non-rotating blade were analyzed with little success in duplicating the deformation results seen in the rotating case. The rotating blade behaves as if it were stiffer than the non-rotating blade resulting in less plastic deformation from a given bird impact. The key factor limiting the success of the non-rotating blade simulations is thought to be the effect of gyroscopics. Prior to this effort, it was anticipated the difficulty would be in matching the prestress in the blade due to centrifugal forces Additional work is needed to verify this assertion, and to determine if a static test procedure can simulate the gyroscopic effects in

  5. Degradation Mechanisms of an Advanced Jet Engine Service-Retired TBC Component

    Science.gov (United States)

    Wu, Rudder T.; Osawa, Makoto; Yokokawa, Tadaharu; Kawagishi, Kyoko; Harada, Hiroshi

    Current use of TBCs is subjected to premature spallation failure mainly due to the formation of thermally grown oxides (TGOs). Although extensive research has been carried out to gain better understanding of the thermo - mechanical and -chemical characteristics of TBCs, laboratory-scale studies and simulation tests are often carried out in conditions significantly differed from the complex and extreme environment typically of a modern gas-turbine engine, thus, failed to truly model service conditions. In particular, the difference in oxygen partial pressure and the effects of contaminants present in the engine compartment have often been neglected. In this respect, an investigation is carried out to study the in-service degradation of an EB-PVD TBC coated nozzle-guide vane. Several modes of degradation were observed due to three factors: 1) presence of residual stresses induced by the thermal-expansion mismatches, 2) evolution of bond coat microstructure and subsequent formation of oxide spinels, 3) deposition of CMAS on the surface of TBC.

  6. In Situ Distribution Guided Analysis and Visualization of Transonic Jet Engine Simulations.

    Science.gov (United States)

    Dutta, Soumya; Chen, Chun-Ming; Heinlein, Gregory; Shen, Han-Wei; Chen, Jen-Ping

    2017-01-01

    Study of flow instability in turbine engine compressors is crucial to understand the inception and evolution of engine stall. Aerodynamics experts have been working on detecting the early signs of stall in order to devise novel stall suppression technologies. A state-of-the-art Navier-Stokes based, time-accurate computational fluid dynamics simulator, TURBO, has been developed in NASA to enhance the understanding of flow phenomena undergoing rotating stall. Despite the proven high modeling accuracy of TURBO, the excessive simulation data prohibits post-hoc analysis in both storage and I/O time. To address these issues and allow the expert to perform scalable stall analysis, we have designed an in situ distribution guided stall analysis technique. Our method summarizes statistics of important properties of the simulation data in situ using a probabilistic data modeling scheme. This data summarization enables statistical anomaly detection for flow instability in post analysis, which reveals the spatiotemporal trends of rotating stall for the expert to conceive new hypotheses. Furthermore, the verification of the hypotheses and exploratory visualization using the summarized data are realized using probabilistic visualization techniques such as uncertain isocontouring. Positive feedback from the domain scientist has indicated the efficacy of our system in exploratory stall analysis.

  7. Engineering chemically exfoliated dispersions of two-dimensional graphite and molybdenum disulphide for ink-jet printing

    Science.gov (United States)

    Michel, Monica; Desai, Jay A.; Biswas, Chandan; Kaul, Anupama B.

    2016-12-01

    Stable ink dispersions of two-dimensional-layered-materials (2DLMs) MoS2 and graphite are successfully obtained in organic solvents exhibiting a wide range of polarities and surface energies. The role of sonication time, ink viscosity and surface tension is explored in the context of dispersion stability using these solvents, which include N-methyl-2-pyrrolidone (NMP), N,N-Dimethylacetamide (DMA), dimethylformamide (DMF), Cyclohexanone (C), as well as less-toxic and more environmentally friendly Isopropanol (IPA) and Terpineol (T). The ink viscosity is engineered through the addition of Ethyl-Cellulose (EC) which has been shown to optimize the jettability of the dispersions. In contrast to prior work, the addition of EC after sonication—instead of prior to it—is noted to be effective in generating a high-density dispersion, yielding a uniform film morphology. High-quality inks are obtained using C/T and NMP as solvents for MoS2 and graphite, respectively, as gauged through optical absorption spectroscopy. Electronic transport data on the solution-cast inks is gathered at room temperature. Arrays of 2D graphite-rod based inks are printed on rigid Si, as well as flexible and transparent polyethylene terephthalate (PET) substrates. The results clearly show the promise of ink-jet printing for casting 2DLMs into hierarchically assembled structures over a range of substrates for flexible and printed-electronics applications.

  8. Elevated Temperature Ballistic Impact Testing of PBO and Kevlar Fabrics for Application in Supersonic Jet Engine Fan Containment Systems

    Science.gov (United States)

    Pereira, J. Michael; Roberts Gary D.; Revilock, Duane M., Jr.

    1997-01-01

    Ballistic impact tests were conducted on fabric made from both Poly(phenylene benzobizoxazole) (PBO) and Kevlar 29 which were selected to be similar in weave pattern, areal density, and fiber denier. The projectiles were 2.54-cm- (1-in.-) long aluminum cylinders with a diameter of 1.27 cm (0.5 in.). The fabric specimens were clamped on four sides in a 30.5-cm- (12-in.-) square frame. Tests on PBO were conducted at room temperature and at 260 C (500 F). A number of PBO specimens were aged in air at 204 and 260 C (400 and 500 F) before impact testing. Kevlar specimens were tested only at room temperature and with no aging. The PBO absorbed significantly more energy than the Kevlar at both room and elevated temperatures. However, after aging at temperatures of 204 C (400 F) and above, the PBO fabric lost almost all of its energy absorbing ability. It was concluded that PBO fabric is not a feasible candidate for fan containment system applications in supersonic jet engines where operating temperatures exceed this level.

  9. Application of computational fluid dynamics to the development of compressors for aero jet engines; Koku engine yo asshukuki kaihatsu eno CFD tekiyo

    Energy Technology Data Exchange (ETDEWEB)

    Hashimoto, K.; Suga, S.; Matsuoka, A.; Sakai, Y. [Kawasaki Heavy Industries, Ltd., Kobe (Japan)

    1997-07-20

    This paper describes studies on application of computational fluid dynamics (CFD) to the development of compressors for aero jet engines, and development of highly-loaded compressor cascade of blades. The compressor used for validation is a single-stage axial-flow transonic compressor using rotor blades with low aspect ratio, whose circumferential velocity at their tips is about 430 m/s and the relative inflow Mach number reaches 1.3. The numerical analysis used a three-dimensional viscosity analysis code based on a high-accuracy upwind scheme using as a governing equation the Navier-Stokes equation for time averaging of three-dimensional compressibility of ideal gas. The calculations were executed on models with two patterns of with or without clearance on the tip of a rotor blade. The calculations were conducted at the design rotation speed and with multiple number of flow rates. The estimation accuracy on the whole performance was evaluated by using the comparison with the test result. The calculations were found 2-4% higher than the experimental values. The maximum flow rate agreed well with the experimental value. A high-performance tandem cascade of rotor blades was developed newly by utilizing the CFD analysis. As a result, the pressure ratio has increased up to 2.7 far exceeding the conventional maximum value of 1.8. A pressure ratio as high as about 50% has been achieved. 9 figs., 1 tab.

  10. An uncoupled multiphase approach towards modeling ice crystals in jet engines

    Science.gov (United States)

    Nilamdeen, Mohamed Shezad

    A recent series of high altitude turbofan engine malfunctions, characterized by flameout and sudden power losses have been reported in recent years. The source of these incidents has been hypothesized to be due to the presence of ice crystals at high altitudes. Ice crystals have been shown to have ballistic trajectories and consequently enter the core engine flow, without getting centrifuged out towards the engine bypass as droplets do. The crystals may melt as they move downstream to higher temperatures in successive stages, or hit a heated surface. The wetted surface may then act as an interface for further crystal impingement, which locally reduces the temperature and could lead to an ice accretion on the components. Ice can accrete to dangerously high levels, causing compressor surge due to blockage of the primary flowpath, vibrational instabilities due to load imbalances of ice on rotating components, mechanical damage of components downstream due to large shed ice fragments, or performance losses if ice enters the combustor, causing a decreased burner efficiency and an eventual flame-out. In order to provide a numerical tool to analyze such situations, FENSAP-ICE has been extended to model mixed-phase flows that combine air, water and ice crystals, and the related ice accretion. DROP3D has been generalized to calculate particle impingement, concentration, and field velocities in an uncoupled approach that neglects any phase change by assuming both ice crystals and supercooled droplets are in thermodynamic equilibrium. ICE3D then accounts for the contribution of ice crystals that stick and melt on an existing water-film and promote ice accretion. The extended ice crystal impingement and ice accretion model has been validated against test data from Cox and Co. and National Research Council icing tests conducted on a NACA0012 airfoil and unheated non-rotating cylinder respectively. The tests show a consistent agreement with respect to experimental profiles in

  11. Effect of Exit Geometry of Tail Pipe on the Performance of Pulse Jet Engines

    Institute of Scientific and Technical Information of China (English)

    Toshihiro NAKANO; Shigeru MATSUO; Kenbu TERAMOTO; Toshiaki SETOGUCHI

    2006-01-01

    In this paper, the effect of geometries of tube open end on the shock, compression and expansion waves propagating in the tube was investigated numerically and experimentally. One of them is a conventional straight shock tube with an open end. The other has a divergent tail tube at the exit. Applying a divergent tail tube (flare tube) to an open end shock tube, the period of one-cycle process could be shortened and the pressure behind the expansion wave produced at the exit of the shock tube could be lowered much more below the atmospheric pressure than that produced in the straight tube. The results suggested that the intake air into the engine was significantly increased by applying a flare tube instead of a straight tube.

  12. Visualization and Analysis of Rotating Stall for Transonic Jet Engine Simulation.

    Science.gov (United States)

    Cher, Chun-Ming; Dutta, Soumya; Liu, Xiaotong; Heinlein, Gregory; Shen, Han-Wei; Chen, Jen-Ping

    2016-01-01

    Identification of early signs of rotating stall is essential for the study of turbine engine stability. With recent advancements of high performance computing, high-resolution unsteady flow fields allow in depth exploration of rotating stall and its possible causes. Performing stall analysis, however, involves Significant effort to process large amounts of simulation data, especially when investigating abnormalities across many time steps. In order to assist scientists during the exploration process, we present a visual analytics framework to identify suspected spatiotemporal regions through a comparative visualization so that scientists are able to focus on relevant data in more detail. To achieve this, we propose efficient stall analysis algorithms derived from domain knowledge and convey the analysis results through juxtaposed interactive plots. Using our integrated visualization system, scientists can visually investigate the detected regions for potential stall initiation and further explore these regions to enhance the understanding of this phenomenon. Positive feedback from scientists demonstrate the efficacy of our system in analyzing rotating stall.

  13. Impeller for Water Jet Propulsion

    Science.gov (United States)

    2004-01-01

    Marshall Space Flight Center engineers helped North American Marine Jet (NAMJ), Inc. improve the proposed design of a new impeller for jet propulsion system. With a three-dimensional computer model of the new marine jet engine blades, engineers were able to quickly create a solid ploycarbonate model of it. The rapid prototyping allowed the company to avoid many time-consuming and costly steps in creating the impeller.

  14. Studies of plasma-jet injection systems to improve ignition conditions in S. I. engine combustion. Untersuchung von Plasmastrahl-Zuendsystemen zur Verbesserung der Zuendbedingungen bei der Verbrennung im Ottomotor

    Energy Technology Data Exchange (ETDEWEB)

    Wilhelmi, H.; Lehmann, A. (Technische Hochschule Aachen (Germany). Inst. fuer Industrieofenbau und Waermetechnik im Huettenwesen); Lepperhoff, G.; Schneider, S. (Technische Hochschule Aachen (Germany). Lehrstuhl fuer Angewandte Thermodynamik)

    1992-01-01

    Calorimetric measurements showed that the efficiency of ignition energy transmission can be enhanced by modifying the level and form of stored energy and the geometry of the spark canal. Optical studies reveal the principal benefit of mixture ignition by a plasma jet which is independent of quenching effects. Engine measurements which were designed and implemented as comparative studies on the transistor/coil/ignition and plasma-jet-ignition systems, confirm measurement results obtained in the laboratory. Clear benefits of plasma-jet ignition were identified for all engine parameters, in particular for pollutant emission, fuel consumption and smooth running. (orig./HW).

  15. Conversion of a micro, glow-ignition, two-stroke engine from nitromethane-methanol blend fuel to military jet propellant (JP-8)

    Science.gov (United States)

    Wiegand, Andrew L.

    The goal of the thesis "Conversion of a Micro, Glow-Ignition, Two-Stroke Engine from Nitromethane-Methanol Blend Fuel to Military Jet Propellant (JP-8)" was to demonstrate the ability to operate a small engine on JP-8 and was completed in two phases. The first phase included choosing, developing a test stand for, and baseline testing a nitromethane-methanol-fueled engine. The chosen engine was an 11.5 cc, glow-ignition, two-stroke engine designed for remote-controlled helicopters. A micro engine test stand was developed to load and motor the engine. Instrumentation specific to the low flow rates and high speeds of the micro engine was developed and used to document engine behavior. The second phase included converting the engine to operate on JP-8, completing JP-8-fueled steady-state testing, and comparing the performance of the JP-8-fueled engine to the nitromethane-methanol-fueled engine. The conversion was accomplished through a novel crankcase heating method; by heating the crankcase for an extended period of time, a flammable fuel-air mixture was generated in the crankcase scavenged engine, which greatly improved starting times. To aid in starting and steady-state operation, yttrium-zirconia impregnated resin (i.e. ceramic coating) was applied to the combustion surfaces. This also improved the starting times of the JP-8-fueled engine and ultimately allowed for a 34-second starting time. Finally, the steady-state data from both the nitromethane-methanol and JP-8-fueled micro engine were compared. The JP-8-fueled engine showed signs of increased engine friction while having higher indicated fuel conversion efficiency and a higher overall system efficiency. The minimal ability of JP-8 to cool the engine via evaporative effects, however, created the necessity of increased cooling air flow. The conclusion reached was that JP-8-fueled micro engines could be viable in application, but not without additional research being conducted on combustion phenomenon and

  16. Mixture formation and pre-reaction in an injection jet in Diesel engine boundary conditions; Gemischbildung und Vorreaktionen in einem Einspritzstrahl unter dieselmotorischen Randbedingungen

    Energy Technology Data Exchange (ETDEWEB)

    Eisele, G.; Koss, H.J.; Knoche, K.F.

    1993-12-31

    To examine the mixture formation and combustion, fuel is injected in Diesel engine boundary conditions in a pressure chamber. Spectroscopic methods permit the noncontact investigation with high spatial and temporal resolution of the physical and chemical processes. The jet of an excimer laser is focussed in the injection jet for this purpose. The local mixture compostion is determined from the Raman spectra, and fluorescence spectra permit one to obtain qualitative information on the appearance and distribution of the OH and NH radicals in the injection jet. For example, it was found that with a chamber temperature of 500 C, the first clear OH fluorescence occurs about 1.8 ms after the start of injection at the edge of the jet in the area of lean mixture. (orig.) [Deutsch] Zur Untersuchung der Gemischbildung und Verbrennung wird Kraftstoff unter dieselmotorischen Randbedingungen in einer Druckkammer eingespritzt. Spektroskopische Methoden erlauben die beruehrungslose und zudem oertlich und zeitlich hochaufgeloeste Untersuchung der physikalischen und chemischen Vorgaenge. Dazu wird der Strahl eines Excimerlasers in den Einspritzstrahl fokussiert. Aus Ramanspektren laesst sich die lokale Gemischzusammensetzung bestimmen, Fluoreszenzspektren erlauben qualitative Aussagen ueber Auftreten und Verteilung der OH- und NH-Radikale im Einspritzstrahl. So zeigt sich zum Beispiel, dass bei einer Kammertemperatur von 500 C die ersten deutlichen OH-Fluoreszenzen ca. 1,8 ms nach Einspritzbeginn am Strahlrand im Bereich mageren Gemisches auftreten (orig.)

  17. Contribution to the study of an lpg jet in the combustion chamber of a spark-ignition engine; Contribution a l'etude d'un jet de gpl dans la chambre de combustion d'un moteur a allumage commande, pour differentes strategies d'injection

    Energy Technology Data Exchange (ETDEWEB)

    Duong Viet, D.

    2002-07-01

    It appears tempting to combine the less polluting combustion of LPG with the energy performances of a direct injection spark-ignition engine. To this aim the study of high pressure injection of a liquid LPG jet, directly inside the combustion chamber of an engine was performed in two ways: Experimental studies: one with fast cinematography and another with the method of Doppler phases in an one-cylinder 'transparent' engine for various conditions of injection and without combustion. They respectively deliver empirical laws for the jet development and some informations about size and speed of the droplets of LPG. A modeling of the jet could then be made on the basis of a turbulent and deviated jet the parameters of which could be adjusted using results of the preceding experimental study. (author)

  18. Influence of Jet Fuel Composition on Aircraft Engine Emissions: A Synthesis of Aerosol Emissions Data from the NASA APEX, AAFEX, and ACCESS Missions

    Science.gov (United States)

    Moore, R.; Shook, M.; Beyersdorf, A. J.; Corr, C.; Herndon, S. C.; Knighton, W. B.; Miake-Lye, R. C.; Thornhill, K. L., II; Winstead, E.; Yu, Z.; Ziemba, L. D.; Anderson, B. E.

    2015-12-01

    We statistically analyze the impact of jet fuel properties on aerosols emitted by the NASA McDonnell Douglas DC-8 CFM56-2-C1 engines burning fifteen different aviation fuels. Data were collected for this single engine type during four different, comprehensive ground tests conducted over the past decade, which allow us to clearly link changes in aerosol emissions to fuel compositional changes. It is found that the volatile aerosol fraction dominates the number and volume emissions indices (EIs) over all engine powers, which are driven by changes in fuel aromatic and sulfur content. Meanwhile, the naphthalenic content of the fuel determines the magnitude of the non-volatile number and volume EI as well as the black carbon mass EI. Linear regression coefficients are reported for each aerosol EI in terms of these properties, engine fuel flow rate, and ambient temperature, and show that reducing both fuel sulfur content and napththalenes to near-zero levels would result in roughly a ten-fold decrease in aerosol number emitted per kg of fuel burn. This work informs future efforts to model aircraft emissions changes as the aviation fleet gradually begins to transition toward low-aromatic, low-sulfur alternative jet fuels from bio-based or Fischer-Tropsch production pathways.

  19. Location of gamma-ray Flare Emission in the Jet of the BL Lacertae Object OJ287 more than 14pc from the Central Engine

    CERN Document Server

    Agudo, Ivan; Marscher, Alan P; Larionov, Valeri M; Gomez, Jose L; Lahteenmaki, Anne; Gurwell, Mark A; Smith, Paul S; Wiesemeyer, Helmut; Thum, Clemens; Heidt, Jochen; Blinov, Dmitriy A; D'Arcangelo, Francesca D; Hagen-Thorn, Vladimir A; Morozova, Daria A; Nieppola, Elina; Roca-Sogorb, Mar; Schmidt, Gary D; Taylor, Brian; Tornikoski, Merja; Troitsky, Ivan S

    2010-01-01

    We combine time-dependent multi-waveband flux and linear polarization observations with sub-milliarcsecond-scale polarimetric images at lambda=7mm of the BL Lacertae-type blazar OJ287 to locate the gamma-ray emission in prominent flares in the jet of the source >14pc from the central engine. We demonstrate a highly significant correlation between the strongest gamma-ray and millimeter-wave flares through Monte-Carlo simulations. The two reported gamma-ray peaks occurred near the beginning of two major mm-wave outbursts, each of which is associated with a linear polarization maximum at millimeter wavelengths. Our Very Long Baseline Array observations indicate that the two mm-wave flares originated in the second of two features in the jet that are separated by >14 pc. The simultaneity of the peak of the higher-amplitude gamma-ray flare and the maximum in polarization of the second jet feature implies that the gamma-ray and mm-wave flares are co-spatial and occur >14 pc from the central engine. We also associate...

  20. Timing of Events in the Central Engine and Jets of the Radio Galaxies 3c 111 and 3c 120 (core Program)

    Science.gov (United States)

    The investigators request continuation of their long-term monitoring of the X-ray flux of the radio galaxies 3C 111 (FR 2) and 3C 120 (FR 1) 2 and 4 times per week, respectively, throughout Cycle 12, as well as a 90 days of daily monitoring of 3C 111. In both objects, dips in X-ray flux precede the appearance of bright superluminal knots in the radio jet. The long-term multiwaveband light curves and sequences of 7 mm VLBA images will record the changing pattern of multiwaveband emission in these two AGN. 3C 111 is a probable EGRET source; if the ID is correct, GLAST will measure its flux daily, allowing relative timing of gamma-ray variations with X-ray and optical events from the central engine plus radio events in the jet.

  1. Jet propagation, atomization and evaporation in diesel engine injection. Strahlausbreitung, Zerstaeubung und Verdampfung bei der dieselmotorischen Einspritzung

    Energy Technology Data Exchange (ETDEWEB)

    Renz, U.; Breuer, A.; Flower, T.; Klingsporn, M.

    1992-01-01

    This report covers the results calculated by different numeral methods and obtained by experiments within studies performed on diesel fuel jet and droplet chains. The comparison of the Euler and Lagrange statements for particle modelling shows the advantage of the Lagrange statement for the description of particulate propagation in the injection jet. A reasonable agreement between experimental results and those established by the Lagrange statement was found. The influence of various parameters like chamber pressure, chamber temperature and injected quantity were studied. (orig.).

  2. Flight test results of an automatic support system on board a YF-12A airplane. [for jet engine inlet air control

    Science.gov (United States)

    Love, J. E.

    1974-01-01

    An automatic support system concept that isolated faults in an existing nonavionics subsystem was flight tested up to a Mach number of 3. The adaptation of the automated support concept to an existing system (the jet engine automatic inlet control system) caused most of the problems one would expect to encounter in other applications. These problems and their solutions are discussed. Criteria for integrating automatic support into the initial design of new subsystems are included in the paper. Cost effectiveness resulted from both the low maintenance of the automated system and the man-hour saving resulting from the real time diagnosis of the monitored subsystem.

  3. Use of a Ni60Ti shape memory alloy for active jet engine chevron application: I. Thermomechanical characterization

    Science.gov (United States)

    Hartl, D. J.; Lagoudas, D. C.; Calkins, F. T.; Mabe, J. H.

    2010-01-01

    A shape memory alloy (SMA) with a composition of Ni60Ti40 (wt%) was chosen for the fabrication of active beam elements intended for use as cyclic actuators and incorporated into a morphing aerospace structure. The active structure is a variable-geometry chevron (VGC) designed to reduce jet engine noise in the take-off flight regime while maintaining efficiency in the cruise regime. This two-part work addresses the training, characterization and derived material properties of the new nickel-rich composition, the assessment of the actuation properties of the active beam actuator and the accurate analysis of the VGC and its subcomponents using a model calibrated from the material characterization. The characterization performed in part I of this work was intended to provide quantitative information used to predict the response of SMA beam actuators of the same composition and with the same heat treatment history. Material in the form of plates was received and ASTM standard tensile testing coupons were fabricated and tested. To fully characterize the material response as an actuator, various thermomechanical experiments were performed. Properties such as actuation strain and transformation temperatures as a function of applied stress were of primary interest. Results from differential scanning calorimetry, monotonic tensile loading and constant stress thermal loading for the as-received, untrained material are first presented. These show lower transformation temperatures, higher elastic stiffnesses (60-90 GPa) and lower recoverable transformation strains (≈1.5%) when compared to equiatomic NiTi (Nitinol). Stabilization (training) cycles were applied to the tensile specimens and characterization tests were repeated for the stable (trained) material. The effects of specimen training included the saturation of cyclically generated irrecoverable plastic strains and a broadening of the thermal transformation hysteresis. A set of final derived material properties for this

  4. 涡轮发动机燃油起动喷嘴调试%Debugging of Turbine Engine Fuel Starting Jet

    Institute of Scientific and Technical Information of China (English)

    杨凯; 王芳琦

    2016-01-01

    In the development stage of a certain type of engine, the fuel starting jet flow exceeds the maximum design value. The conventional coping method can't make the flow value drop to the design value scope. So it is necessary to redesign the key dimension of the starting jet. On the basis of the working principle of the centrifugal nozzle and related theory, combined with test piece debugging, the structural dimension is adjusted. Through practical test and batch processing, the reasonability of the change and precision of the calculation is verified. At last the design of the starting jet is finalized.%某型发动机在研制阶段出现燃油起动喷嘴流量值超出设计值上限问题,采用常规修磨方法无法将流量值降至设计值范围内,需对起动喷嘴关键尺寸进行重新设计.针对该问题,以离心式喷嘴工作原理及相关理论为基础,结合试验件调试,对该起动喷嘴的结构尺寸进行了调整.经过实测和批量加工,验证了改动的合理性和计算的准确性,最终使该起动喷嘴顺利定型.

  5. Jet engine test stand and soil stockpile. 107th fighter-interceptor group Niagara Falls Air Force Reserve Station, New York Air National Guard, Niagara Falls, New York. Final site assessment addendum report, 9-12 February 1993

    Energy Technology Data Exchange (ETDEWEB)

    1994-03-01

    THis report outlines additional site assessment activities which were conducted at the Jet Engine Test Stand (JETS), Building No. 852 located at the 197th Fighter-Interceptor Group, Niagara Falls Air National Guard Station (NFANGS), Air Force Reserve Facility (AFRF) approximately 6 miles northeast of Niagara Falls, New York (Figure 1.1). The additional site assessment activities were performed in response to requests, dated February 9 and 12, 1993, by the New York State Department of Environmental Conservation (NYSDEC) to further investigate contaminated soil and groundwater conditions at the JETS and at an existing soil stockpile (Appendix A).

  6. MHD-, ships-, jet engine unit consisting of electrochemical cells producing hydrogen, magneto-caloric hydrogen liquefier, liquid hydrogen-cooled high temperature superconductor-, MHD-, jet engine, liquid hydrogen internal combustion engine as high temperature-, superconductor-, generator-drive. High temperature superconductor coil and permanent magnet superconductor hollow cylinder as battery. MHD-Schiffs-Strahltriebwerks-Aggregat bestehend aus Wasserstoff-produzierenden elektrochemischen Solarzellen, magnetokalorischem Wasserstoffverfluessiger, Fluessigwasserstoff gekuehltem Hochtemperatur-Supraleiter-MHD-Strahltriebwerk, Fluessigwasserstoff-Verbrennungsmotor als Hochtemperatur-Supraleiter-Generator-Antrieb, Hochtemperatur-Supraleiter-Spule und permanentmagnetischem Supraleiter-Hohlzylinder als Akku

    Energy Technology Data Exchange (ETDEWEB)

    Berling, E.

    1991-05-02

    MHD-, ships-, jet engine-unit consisting of electrochemical cells producing hydrogen, magneto-caloric hydrogen liquifier, liquid hydrogen-cooled high temperature superconductor-, MHD-, jet engine, liquid hydrogen internal combustion engine as high temperature-, superconductor-, generator-drive. High temperature superconductor coil and permanent magnet superconductor hollow cylinder as battery. Ships water jet engines with magneto hydrodynamic (MHD) low temperature superconductor drive are known. The invention of the ceramic high temperature superconductor MHD drive, which is cooled with liquid hydrogen. The hydrogen is obtained electro-chemically directly from seawater, and is liquified magneto-calorically. The high temperature superconductor elements of the engine, liquifier, generator, storage coil, permanent magnet hollow cylinder store are coupled by a common liquid hydrogen cooling circuit. The internal combustion engine driving the generator is fuelled by the same liquid hydrogen by which the high temperature superconductor elements are cooled.

  7. Location of γ-ray Flare Emission in the Jet of the BL Lacertae Object OJ287 More than 14 pc from the Central Engine

    Science.gov (United States)

    Agudo, Iván; Jorstad, Svetlana G.; Marscher, Alan P.; Larionov, Valeri M.; Gómez, José L.; Lähteenmäki, Anne; Gurwell, Mark; Smith, Paul S.; Wiesemeyer, Helmut; Thum, Clemens; Heidt, Jochen; Blinov, Dmitriy A.; D'Arcangelo, Francesca D.; Hagen-Thorn, Vladimir A.; Morozova, Daria A.; Nieppola, Elina; Roca-Sogorb, Mar; Schmidt, Gary D.; Taylor, Brian; Tornikoski, Merja; Troitsky, Ivan S.

    2011-01-01

    We combine time-dependent multi-waveband flux and linear polarization observations with submilliarcsecond-scale polarimetric images at λ = 7 mm of the BL Lacertae type blazar OJ287 to locate the γ-ray emission in prominent flares in the jet of the source >14 pc from the central engine. We demonstrate a highly significant correlation between the strongest γ-ray and millimeter-wave flares through Monte Carlo simulations. The two reported γ-ray peaks occurred near the beginning of two major millimeter-wave outbursts, each of which is associated with a linear polarization maximum at millimeter wavelengths. Our very long baseline array observations indicate that the two millimeter-wave flares originated in the second of two features in the jet that are separated by >14 pc. The simultaneity of the peak of the higher-amplitude γ-ray flare and the maximum in polarization of the second jet feature implies that the γ-ray and millimeter-wave flares are cospatial and occur >14 pc from the central engine. We also associate two optical flares, accompanied by sharp polarization peaks, with the two γ-ray events. The multi-waveband behavior is most easily explained if the γ-rays arise from synchrotron self-Compton scattering of optical photons from the flares. We propose that flares are triggered by interaction of moving plasma blobs with a standing shock. The γ-ray and optical emission is quenched by inverse Compton losses as synchrotron photons from the newly shocked plasma cross the emission region. The millimeter-wave polarization is high at the onset of a flare, but decreases as the electrons emitting at these wavelengths penetrate less polarized regions.

  8. 发动机热喷流红外辐射计算与仿真%Calculation and Simulation on Infrared Radiation of Hot Jet from Engine

    Institute of Scientific and Technical Information of China (English)

    李建勋; 童中翔; 王超哲; 童奇; 李贺; 张志波

    2013-01-01

    利用求每个小视场视线方向辐射亮度的方法计算喷流红外辐射的光谱分布.以辐射传递方程数值和形式为基础,采用Malkmus统计窄谱带模型和Curtis-Godson (CG)近似求视线方向的辐射强度.采用CFD分析软件FLUENT模拟流场和组分摩尔分数分布.建立喷流红外成像仿真模型,仿真生成了液体火箭发动机热喷流红外图像.结果表明,该方法可以很好地分辨出流场的细微结构.该模型也适用于航空发动机喷流红外辐射计算与仿真.%Spectral distribution of infrared radiation from plume by the method to calculate infrared radiance of the gaze direction in small sight field was calculated. Based on numerical value and form of radiative transfer equation, infrared radiant intensity of the gaze direction was calculated using the Malkmus statistical narrow-band model and CG approach. Flow field and mole fraction distribution were simulated using a FLUENT computational fluid dynamic (CFD) software. Infrared imaging simulation model of hot jet was established. The hot jet's infrared images of liquid rocket engine were generated. The results demonstrate that the method can detect well-resolved fine structure of flow field. And the model is also applicable to calculation and simulation on infrared radiation of hot jet from engine.

  9. Jet observables without jet algorithms

    Energy Technology Data Exchange (ETDEWEB)

    Bertolini, Daniele; Chan, Tucker; Thaler, Jesse [Center for Theoretical Physics, Massachusetts Institute of Technology,Cambridge, MA 02139 (United States)

    2014-04-02

    We introduce a new class of event shapes to characterize the jet-like structure of an event. Like traditional event shapes, our observables are infrared/collinear safe and involve a sum over all hadrons in an event, but like a jet clustering algorithm, they incorporate a jet radius parameter and a transverse momentum cut. Three of the ubiquitous jet-based observables — jet multiplicity, summed scalar transverse momentum, and missing transverse momentum — have event shape counterparts that are closely correlated with their jet-based cousins. Due to their “local” computational structure, these jet-like event shapes could potentially be used for trigger-level event selection at the LHC. Intriguingly, the jet multiplicity event shape typically takes on non-integer values, highlighting the inherent ambiguity in defining jets. By inverting jet multiplicity, we show how to characterize the transverse momentum of the n-th hardest jet without actually finding the constituents of that jet. Since many physics applications do require knowledge about the jet constituents, we also build a hybrid event shape that incorporates (local) jet clustering information. As a straightforward application of our general technique, we derive an event-shape version of jet trimming, allowing event-wide jet grooming without explicit jet identification. Finally, we briefly mention possible applications of our method for jet substructure studies.

  10. Renewable jet fuel.

    Science.gov (United States)

    Kallio, Pauli; Pásztor, András; Akhtar, M Kalim; Jones, Patrik R

    2014-04-01

    Novel strategies for sustainable replacement of finite fossil fuels are intensely pursued in fundamental research, applied science and industry. In the case of jet fuels used in gas-turbine engine aircrafts, the production and use of synthetic bio-derived kerosenes are advancing rapidly. Microbial biotechnology could potentially also be used to complement the renewable production of jet fuel, as demonstrated by the production of bioethanol and biodiesel for piston engine vehicles. Engineered microbial biosynthesis of medium chain length alkanes, which constitute the major fraction of petroleum-based jet fuels, was recently demonstrated. Although efficiencies currently are far from that needed for commercial application, this discovery has spurred research towards future production platforms using both fermentative and direct photobiological routes. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. Long-term health experience of jet engine manufacturing workers: VIII. glioblastoma incidence in relation to workplace experiences with parts and processes.

    Science.gov (United States)

    Marsh, Gary M; Youk, Ada O; Buchanich, Jeanine M; Downing, Sarah; Kennedy, Kathleen J; Esmen, Nurtan A; Hancock, Roger P; Lacey, Steven E; Pierce, Jennifer S; Fleissner, Mary Lou

    2013-06-01

    To determine whether glioblastoma (GB) incidence rates among jet engine manufacturing workers were associated with workplace experiences with specific parts produced and processes performed. Subjects were 210,784 workers employed between 1952 and 2001. We conducted nested case-control and cohort incidence studies with focus on 277 GB cases. We estimated time experienced with 16 part families, 4 process categories, and 32 concurrent part-process combinations with 20 or more GB cases. In both the cohort and case-control studies, none of the part families, process categories, or both considered was associated with increased GB risk. If not due to chance alone, the not statistically significantly elevated GB rates in the North Haven plant may reflect external occupational factors or nonoccupational factors unmeasured in the current evaluation.

  12. Lunar surface traces of engine jets of Soviet sample return probes: The enigma of the Luna-23 and Luna-24 landing sites

    Science.gov (United States)

    Shkuratov, Yuriy; Kaydash, Vadym; Sysolyatina, Xenija; Razim, Alexandra; Videen, Gorden

    2013-01-01

    We use a photometric method called phase-ratio imaging to study the landing sites of the Soviet Luna-16, Luna-20, Luna-23 and Luna-24 probes using the survey data of the lunar surface, which was carried out with the Narrow-Angle Cameras (NACs) of the Lunar Reconnaissance Orbiter (LRO) spacecraft. The phase-ratio images clearly show diffuse features associated with structure perturbations of the lunar regolith. We suggest that these features are caused by the impact of the gas jets from the rocket engines. The photometric anomalies around the landing sites suggest that the impacts smooth out the surface, destroying the primordial "fairy castle" structure that effectively produces the shadow-hiding effect. The same characteristic features have been found previously for the Apollo spacecraft landings, but over larger spatial scales. The only exception is the landing site of the Luna-24 probe, for which the feature of the possible impact of the gas jets is shifted to the northwest by approximately 150 m. As the Luna-24 descent module worked in the regular mode and could not allow such a shift as the probe was descending vertically, a possible explanation is that the sites of Luna-23 (an unsuccessful sample return mission) and Luna-24 are misidentified. The distance between the sites is about 2 km, which is within the inaccuracy of their coordinate determination. We suggest that because of faulty processing of the radar system for distance/speed control, the incorrectly operated engine and/or thrusters of Luna-23 produced the 150 m lateral drift before final deactivation and hard descent. To better understand the geologic situation, we produce brightness and phase-ratio anaglyphs for the vicinity of the landings.

  13. Early Jet Engines and the Transition from Centrifugal to Axial Compressors: A Case Study in Technological Change

    Science.gov (United States)

    1988-01-01

    Aeronautical Society 52 (January 1948): 76. 29 Robert Schlaifer, Development of Aircraft Engines (Boston: Harvard University Graduate School of Business ...34 Transactions of the Newcomen Society 28 (1953): 188-89. Harris also points out that inventions of Agricola and Ramelli which resembled centrifugal fans were...Publishers, Inc., 1979), p. 10; and Robert Schlaifer, Development of Aircraft Engines (Boston: Harvard University Graduate S.hool of Business

  14. Fuzzy jets

    Energy Technology Data Exchange (ETDEWEB)

    Mackey, Lester [Department of Statistics, Stanford University,Stanford, CA 94305 (United States); Nachman, Benjamin [Department of Physics, Stanford University,Stanford, CA 94305 (United States); SLAC National Accelerator Laboratory, Stanford University,2575 Sand Hill Rd, Menlo Park, CA 94025 (United States); Schwartzman, Ariel [SLAC National Accelerator Laboratory, Stanford University,2575 Sand Hill Rd, Menlo Park, CA 94025 (United States); Stansbury, Conrad [Department of Physics, Stanford University,Stanford, CA 94305 (United States)

    2016-06-01

    Collimated streams of particles produced in high energy physics experiments are organized using clustering algorithms to form jets. To construct jets, the experimental collaborations based at the Large Hadron Collider (LHC) primarily use agglomerative hierarchical clustering schemes known as sequential recombination. We propose a new class of algorithms for clustering jets that use infrared and collinear safe mixture models. These new algorithms, known as fuzzy jets, are clustered using maximum likelihood techniques and can dynamically determine various properties of jets like their size. We show that the fuzzy jet size adds additional information to conventional jet tagging variables in boosted topologies. Furthermore, we study the impact of pileup and show that with some slight modifications to the algorithm, fuzzy jets can be stable up to high pileup interaction multiplicities.

  15. Analysis of middle bearing failure in rotor jet engine using tip-timing and tip-clearance techniques

    Science.gov (United States)

    Rzadkowski, R.; Rokicki, E.; Piechowski, L.; Szczepanik, R.

    2016-08-01

    The reported problem is the failure of the middle bearing in an aircraft rotor engine. Tip-timing and tip-clearance and variance analyses are carried out on a compressor rotor blade in the seventh stage above the middle bearing. The experimental analyses concern both an aircraft engine with a middle bearing in good working order and an engine with a damaged middle bearing. A numerical analysis of seventh stage blade free vibration is conducted to explain the experimental results. This appears to be an effective method of predicting middle bearing failure. The results show that variance first increases in the initial stages of bearing failure, but then starts to decrease and stabilize, and then again decrease shortly before complete bearing failure.

  16. Fundamental Study of Direct Injection Diesel Engine Fuelled with Hydrogen(1st Report: Analysis on Process of Mixture Formation in Unsteady Hydrogen Jet)

    OpenAIRE

    藤本, 元; 千田, 二郎; 大田, 篤志; フジモト, ハジメ; センダ, ジロウ; オオタ, アツシ; Fujimoto, Hajime; Senda, Jiro; Ohta, Atsushi

    2004-01-01

    In this study, the mixture formation processes of high pressure hydrogen jets were investigated using a constant-volume vessel. The mixture formations of steady gas jets injected into atmospheric pressure ambient are well known. However, there are few works about the mixture formations of high pressure hydrogen jets injected into high pressure ambient. Also, in gas releases having a pressure ratio of exit pressure to ambient pressure greater than 1.89, underexpanded jet will be formed. So the...

  17. Durability of zirconia thermal-barrier ceramic coatings on air-cooled turbine blades in cyclic jet engine operation

    Science.gov (United States)

    Liebert, C. H.; Jacobs, R. E.; Stecura, S.; Morse, C. R.

    1976-01-01

    Thermal barrier ceramic coatings of stabilized zirconia over a bond coat of Ni Cr Al Y were tested for durability on air cooled turbine rotor blades in a research turbojet engine. Zirconia stabilized with either yttria, magnesia, or calcia was investigated. On the basis of durability and processing cost, the yttria stabilized zirconia was considered the best of the three coatings investigated.

  18. Jet Observables Without Jet Algorithms

    CERN Document Server

    Bertolini, Daniele; Thaler, Jesse

    2013-01-01

    We introduce a new class of event shapes to characterize the jet-like structure of an event. Like traditional event shapes, our observables are infrared/collinear safe and involve a sum over all hadrons in an event, but like a jet clustering algorithm, they incorporate a jet radius parameter and a transverse momentum cut. Three of the ubiquitous jet-based observables---jet multiplicity, summed scalar transverse momentum, and missing transverse momentum---have event shape counterparts that are closely correlated with their jet-based cousins. Due to their "local" computational structure, these jet-like event shapes could potentially be used for trigger-level event selection at the LHC. Intriguingly, the jet multiplicity event shape typically takes on non-integer values, highlighting the inherent ambiguity in defining jets. By inverting jet multiplicity, we show how to characterize the transverse momentum of the n-th hardest jet without actually finding the constituents of that jet. Since many physics applicatio...

  19. REVIEW OF WATER JET APPLICATIONS IN MANUFACTURING

    OpenAIRE

    Faruk MENDİ; KÜLEKÇİ, Mustafa Kemal

    1999-01-01

    Usage of water jets in manufacturing processes, has been known for many decades. A wide range of engineering materials can be cut by water jets with satisfactory results. Enhanced reliability and efficiency of the technique, have yielded the technology greater interest for manufacturing applications. Water jets are used to cut soft materials such as wood, plastics, aluminium and copper. Abrasive water jets are used to cut very hard materials such as titanium, inconel, glass and ceramics. It i...

  20. HITEMP derived spectral database for the prediction of jet engine exhaust infrared emission using a statistical band model

    Science.gov (United States)

    Lindermeir, E.; Beier, K.

    2012-08-01

    The spectroscopic database HITEMP 2010 is used to upgrade the parameters of the statistical molecular band model which is part of the infrared signature prediction code NIRATAM (NATO InfraRed Air TArget Model). This band model was recommended by NASA and is applied in several codes that determine the infrared emission of combustion gases. The upgrade regards spectral absorption coefficients and line densities of the gases H2O, CO2, and CO in the spectral region 400-5000 cm-1 (2-25μm) with a spectral resolution of 5 cm-1. The temperature range 100-3000 K is covered. Two methods to update the database are presented: the usually applied method as provided in the literature and an alternative, more laborious procedure that employs least squares fitting. The achieved improvements resulting from both methods are demonstrated by comparisons of radiance spectra obtained from the band model to line-by-line results. The performance in a realistic scenario is investigated on the basis of measured and predicted spectra of a jet aircraft plume in afterburner mode.

  1. Robot based three-dimensional welding for jet engine blade repair and rapid prototyping of small components

    Science.gov (United States)

    Thukaram, Santosh Kumar

    Aero engines are made up of a large number of blades which are subject to wear and damage. They are expensive and must be repaired wherever possible. Engines also have small components which are required in small numbers that need to be developed rapidly. The first part of this research work focuses on developing a robust automated blade repair method using robotic welding. Optimal weld parameters were developed for build-up of edges having different thicknesses. Samples with varying Current and varying travel speed were produced and their micro hardness values were compared. Blade profiles were welded upon. The second part involves a methodology for producing small components using rapid prototyping (RP) techniques. This part involves use of 3D robotic welding for layered manufacturing. Tensile samples produced using the metal RP method were tested and results were found to be well above the minimum cast specifications for the given material.

  2. Jet propagation, atomization and evaporation in diesel-engine injection. Strahlausbreitung, Zerstaeubung und Verdampfung bei der dieselmotorischen Einspritzung

    Energy Technology Data Exchange (ETDEWEB)

    Bohn, D.; Dibelius, G.; Funcke, J.; Holzenthal, K.; Fitzky, G.

    1992-01-01

    In the direct-injection diesel engine, the course of combustion is largely a function of the distribution of the fuel in the combustion space and of the subsequent mixture formation process due to the short time span between the onset of fuel injection and ignition. To improve combustion for high efficiency and low pollutant and noise emissions, exact knowledge is needed about the course of atomization, evaporation and mixing processes and their respective action mechanisms. (orig.).

  3. Research on the combustor module of a turbojet engine for the super/hypersonic transport; Choonsoku yusokiyo turbo jet engine no nenshoki module no kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Fujiwara, K.; Takagi, S.; Enzaki, Y.; Hayashi, M.; Ariyoshi, K.; Kimura, H.; Kobayashi, M.; Nomi, S. [Kawasaki Heavy Industries, Ltd., Tokyo (Japan)

    1994-10-20

    This paper describes an interim report on the turbojet engine combustor being developed under a large project `Research on Propulsion Systems for Super/Hypersonic Transport` sponsored by the Agency of Industrial Science and Technology of the Ministry of International Trade and Industry. Element research was carried out on 1600-{degree}C class combustors, and operation tests were conducted on prototype core engines as the first research stage. With regard to research on the cooling structures, a selection was made on a structure that uses convection films as the basic structure and adopts at the same time an effusion to improve the wall temperature distribution. Research on equalizing the outlet temperature distribution used a fuel nozzle of air-flow micronizing system, and given improvements on it. The strength design has conducted analyses by using the finite element method to determine sizes and locations of cooling air holes, and the clearance between the high-pressure turbine nozzle and the combustor liner when assembling them. Operation tests of the prototype core engines resulted in achieving a total operation time of 4 hours and 41 minutes, and a maximum temperature at the combustor outlet of 1100{degree}C for 3 minutes under a steady-state condition and 1300{degree}C under a transient condition. 14 figs.

  4. The Applications of Dry Jet Mixing in the Coastal Areas of Hydraulic Engineering%粉喷桩在沿海地区水利工程中的的应用

    Institute of Scientific and Technical Information of China (English)

    戴恩运

    2013-01-01

      在沿海地区水利工程中,水泥粉喷搅拌桩是地基与基础处理常用的一种方法。本文通过作者的工作实践,并结合工程实例对粉喷桩在沿海地区水利工程中的应用进行简单的阐述与分析。%In the coastal areas of hydraulic engineering, the c-ement powder jet mixing pile is a common method of the sub-grade and the basis of processing. In this article, the author ba-ses on the working practices, briefly elaborates and analysis th-e applications of Dry Jet Mixing in the coastal areas of hydrau-lic engineering.

  5. Real-time diagnostics of a jet engine exhaust using an intra-pulse quantum cascade laser spectrometer

    Science.gov (United States)

    Duxbury, Geoffrey; Hay, Kenneth G.; Langford, Nigel; Johnson, Mark P.; Black, John D.

    2011-09-01

    It has been demonstrated that an intra-pulse scanned quantum cascade laser spectrometer may be used to obtain real-time diagnostics of the amounts of carbon monoxide, carbon dioxide, and water, in the exhaust of an aero gas turbine (turbojet) engine operated in a sea level test cell. Measurements have been made of the rapid changes in composition following ignition, the composition under steady state operating conditions, and the composition changes across the exhaust plume. The minimum detection limit for CO in a double pass through a typical gas turbine plume of 50 cm in diameter, with 0.4 seconds integration time, is approximately 2 ppm.

  6. Remote sensing of temperature and concentration profiles of a gas jet by coupling infrared emission spectroscopy and LIDAR for characterization of aircraft engine exhaust

    Science.gov (United States)

    Offret, J.-P.; Lebedinsky, J.; Navello, L.; Pina, V.; Serio, B.; Bailly, Y.; Hervé, P.

    2015-05-01

    Temperature data play an important role in the combustion chamber since it determines both the efficiency and the rate of pollutants emission of engines. Air pollution problem concerns the emissions of gases such as CO, CO2, NO, NO2, SO2 and also aerosols, soot and volatile organic compounds. Flame combustion occurs in hostile environments where temperature and concentration profiles are often not easy to measure. In this study, a temperature and CO2 concentration profiles optical measurement method, suitable for combustion analysis, is discussed and presented. The proposed optical metrology method presents numerous advantages when compared to intrusive methods. The experimental setup comprises a passive radiative emission measurement method combined with an active laser-measurement method. The passive method is based on the use of gas emission spectroscopy. The experimental spectrometer device is coupled with an active method. The active method is used to investigate and correct complex flame profiles. This method similar to a LIDAR (Light Detection And Ranging) device is based on the measurement of Rayleigh scattering of a short laser pulse recorded using a high-speed streak camera. The whole experimental system of this new method is presented. Results obtained on a small-scale turbojet are shown and discussed in order to illustrate the potentials deliver by the sophisticated method. Both temperature and concentration profiles of the gas jet are presented and discussed.

  7. Investigation into the Impact of Hold Time, Thermal Mechanical Fatigue, Shotpeen, and Retardation on Fatigue Crack Growth in Inconel Dovetail Slots in Jet Engines

    Science.gov (United States)

    Joiner, Josiah W.

    2011-12-01

    Current jet engine industry studies are ongoing to develop a generic Inconel dovetail slot test case that will be used for calibrating a manufacturing-induced surface damage anomaly distribution curve for future probabilistic life assessments. The stress and temperature profile during the mission have been defined. This analysis will consist of a design of experiments on the Inconel dovetail slot test data. The test case includes thermal and mechanical stresses, as well as variations in hold time, stress and temperature regimes. Several DOEs will be created and run to help assess the impact of four crack growth mechanisms on the damage tolerance life for the different mission profiles: hold time, thermal mechanical fatigue, shotpeen, and retardation. For the sake of this study a parametric study is considered to be a DOE. Calculations will be completed for both surface and corner cracks. For surface cracks, a 2:1 aspect ratio semicircular initial flaw size of 15 x 30 mils will be used. For corner cracks, a 1:1 aspect ratio semicircular initial flaw size of 15 x 15 mils will be used. The calculations will be completed using a proprietary crack propagation code. The results of this study will reveal the mission profile at which each of the aforementioned effects begins to have a significant impact on the damage tolerance life. These studies are critical to ensuring the final test case adequately addresses each of these critical crack propagation drivers.

  8. Modelling the ignition process on the injection jet for Diesel engine combustion; Modellierung des Zuendvorgangs am Einspritzstrahl bei dieselmotorischer Verbrennung

    Energy Technology Data Exchange (ETDEWEB)

    Pitsch, H.; Mueller, U.C.; Peters, N.

    1995-12-31

    A simplified chemical model is developed to describe Diesel engine self-ignition processes. It is assumed that the ignition of Diesel fuel can be described by the single component fuel n-heptane. Starting from a detailed reaction mechanism for n-heptane with about 1000 element reactions and 168 chemical substances, a starting mechanism with 81 element reactions and 37 chemical substances is produced by a reaction flow analysis which can describe ignition processes in conditions relevant for Diesel engines. The introduction of steady state assumptions for quickly consumed intermediate species leads to a reduced mechanism with 14 global reaction steps. In order to prove the validity of these reduced mechanisms, calculated ignition delay times are compared with surge wave tube experiments for different temperatures, pressures and fuel ratios. Finally, one dimensional calculations of ignition processes in the mixing space for pressures and temperatures relevant for engines are introduced. From these, the effect of the scalar dissipation rate which describes the extent of diffusion flames on the ignition delay times, is discussed. An approximation formula for the ignition delay times as a function of the dissipation rate is derived. (orig.) [Deutsch] Zur Beschreibung dieselmotorischer Selbstzuendprozesse wird ein vereinfachtes chemisches Modell entwickelt. Dazu wird angenommen, dass die Zuendung von Dieselkraftstoffen durch den Einkomponentenkraftstoff n-Heptan beschrieben werden kann. Ausgehend von einem detaillierten Reaktionsmechanismus fuer n-Heptan mit ungefaehr 1000 Elementarreaktionen und 168 chemischen Spezies wird mittels einer Reaktionsflussanalyse ein Startmechanismus mit 81 Elementarreaktionen und 37 chemischen Spezies erstellt, der in der Lage ist, Zuendprozesse unter dieselmotorisch relevanten Bedingungen zu beschreiben. Die Einfuehrung von Stationaritaetsannahmen fuer schnell verbrauchte Zwischenspezies fuehrt auf einen reduzierten Mechanismus mit 14

  9. Properties of jet engine combustion particles during the PartEmis experiment. Hygroscopic growth at supersaturated conditions

    Science.gov (United States)

    Hitzenberger, R.; Giebl, H.; Petzold, A.; Gysel, M.; Nyeki, S.; Weingartner, E.; Baltensperger, U.; Wilson, C. W.

    2003-07-01

    During the EU Project PartEmis, the microphysical properties of aircraft combustion aerosol were investigated. This study is focused on the ability of exhaust aerosols to act as cloud condensation nuclei (CCN). The combustor was operated at two different conditions representing old and modern aircraft engine technology. CCN concentrations were measured with the University of Vienna CCN counter [ Giebl et al., 2002] at supersaturations around 0.7%. The activation ratio (fraction of CCN in total aerosol) depended on the fuel sulphur content (FSC) and also on the operation conditions. CCN/CN ratios increased from 0.93 through 1.43 to 5.15 . 10-3 (old cruise conditions) and 0.67 through 3.04 to 7.94 . 10-3 (modern cruise conditions) when FSC increased from 50 through 410 to1270 μg/g. The activation behaviour was modelled using classical theories and with a semi-empirical model [ Gysel et al., 2003] based on measured hygroscopicity of the aerosol under subsaturated conditions, which gave the best agreement.

  10. Development of medium-sized medium-speed lean burn spark-ignited gas engines. Analyzing local gas composition within the main combustion chamber and optimizing the design factors of a jet hole in the pre-combustion chamber; Chugata chusoku kihakunensho gas engine no kaihatsu kenkyu. Nenshoshitsunai kyokusho gas sosei no bunseki to yonenshoshitsu funko sekkei yoso no saitekika ni kansuru ichikosatsu

    Energy Technology Data Exchange (ETDEWEB)

    Goto, S.; Sakagami, T.; Hashimoto, T. [Niigata Engineering Co. Ltd., Tokyo (Japan)

    1996-10-25

    A high-speed gas sampling method was used to analyze the local gas composition within the main combustion chamber of a lean burn gas engine with a 260 mm bore. The spatial distribution of the gas composition and changes every crank angle were studied. The optimum design of a jet hole in the pre-combustion chamber was then investigated based on these results, with the aim of reducing CO and THC concentration and increasing the thermal efficiency. The engineering findings were evaluated by means of a performance test on a 6 cylinder engine. 4 refs., 10 figs., 1 tab.

  11. Heterogeneous-phase reactions of nitrogen dioxide with vermiculite-supported magnesium oxide (as applied to the control of jet engine test cell emissions). Doctoral thesis

    Energy Technology Data Exchange (ETDEWEB)

    Kimm, L.T.

    1995-11-01

    Controlling nitrogen oxides (NOx) from a non-steady-state stationary source like a jet engine test cell (JETC) requires a method that is effective over a wide range of conditions. A heterogeneous, porous, high surface area sorbent material comprised of magnesium oxide powder attached to a vermiculite substrate has been commercially developed for this purpose. Data from extensive laboratory testing of this material in a packed-bed flow system are presented. NO2 removal efficiencies, kinetics, and proposed NO2 removal mechanisms over a range of representative JETC exhaust gas characteristics are described. Exhaust gas variables evaluated included: NO2 concentration, temperature, flow rate (retention time), oxygen content, and moisture content. Availability of water and oxygen were found to be important variables. It is probable that water is necessary for the conversion of MgO to Mg(OH)2, which is a more reactive compound having thermal stability over the range of temperatures evaluated. Gaseous oxygen serves to oxidize NO to NO2, the latter being more readily removed from the gas stream. The presence of oxygen also serves to offset thermal decomposition of NO2 or surface nitrite/nitrate. Effective `lifetime` and regenerability of the exposed sorbent material were also evaluated. NO2 removal efficiencies were found to greatly exceed those for NO, with a maximum value greater than 90 percent. The effective conversion of NO to NO2 is a crucial requirement for removal of the former. The reaction between NO2 and MgO-vermiculite is first-order with respect to NO2.

  12. Modeling and experimental study of the mechanism of electrification from aero-engine jet%航空发动机喷流起电机理建模与试验研究

    Institute of Scientific and Technical Information of China (English)

    朱利; 刘尚合; 郑会志; 魏明; 胡小锋; 索罗金·安德烈

    2013-01-01

    以研究航空发动机喷流起电的机理以及喷流起电对飞行器整体带电特性的影响为目的,对起电机理进行了建模和实验验证。首先以流体运动方程为基础,建立了航空发动机带电粒子浓度的动态仿真模型,仿真得到发动机燃烧过程中的各类粒子浓度变化情况。其次,设计了用于发动机喷流起电探测的静电感应传感器,对装配涡扇发动机的某型飞行器进行了地面试验测试,得到了发动机启动、稳定运行、加速、减速、停止等状态的动态电位。仿真及实验结果详细地描述了发动机喷流起电的机理,以及喷流起电会使飞行器带负电的结论,为进一步分析飞行器飞行过程中整体带电特性提供了指导。%To investigate the mechanism of electrification from aero-engine jet and the electrification effect on the overall charging charac-teristics of vehicle, a simulation model of concentration of charged particles in aero-engine is build based on the equations of fluid motion. And concentration changes of various particles are simulated. To verify the simulation result, a special electrostatic induction sensor for detecting the electrification of engine jet is designed, according to the principle of the Faraday cup, to measure the dynamic potential when the turbofan engine starts, operates steadily, accelerates, decelerates and stops. The simulation and experimental re-sults show that the aircraft is negatively charged by the electrification from aero-engine jet and the mechanism of electrification from aero-engine jet is described specifically. The research may provide a guidance to the further study on analyzing the overall charging characteristics of vehicle during the flight.

  13. Engine Cold Start

    Science.gov (United States)

    2015-09-01

    14. ABSTRACT These fuels were used for testing a GEP 6.5L turbocharged V-8 diesel engine operation in a cold box. This engine architecture is... engines . The U.S. military currently uses petroleum-based jet fuels in diesel engine -powered ground vehicles and is studying the use of alternative jet...to identify a window, or range, of cetane number which would be acceptable to ensure the reliable operation of diesel engine -powered military ground

  14. Jet quenching via jet collimation

    CERN Document Server

    Casalderrey-Solana, J; Wiedemann, U

    2011-01-01

    The strong modifications of dijet properties in heavy ion collisions measured by ATLAS and CMS provide important constraints on the dynamical mechanisms underlying jet quenching. In this work, we show that the transport of soft gluons away from the jet cone - jet collimation - can account for the observed dijet asymmetry with values of $\\hat{q}\\, L$ that lie in the expected order of magnitude. Further, we show that the energy loss attained through this mechanism results in a very mild distortion of the azimuthal angle dijet distribution.

  15. Emerging jets

    Energy Technology Data Exchange (ETDEWEB)

    Schwaller, Pedro; Stolarski, Daniel [European Organization for Nuclear Research (CERN), Geneva (Switzerland). TH-PH Div.; Weiler, Andreas [European Organization for Nuclear Research (CERN), Geneva (Switzerland). TH-PH Div.; Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2015-02-15

    In this work, we propose a novel search strategy for new physics at the LHC that utilizes calorimeter jets that (i) are composed dominantly of displaced tracks and (ii) have many different vertices within the jet cone. Such emerging jet signatures are smoking guns for models with a composite dark sector where a parton shower in the dark sector is followed by displaced decays of dark pions back to SM jets. No current LHC searches are sensitive to this type of phenomenology. We perform a detailed simulation for a benchmark signal with two regular and two emerging jets, and present and implement strategies to suppress QCD backgrounds by up to six orders of magnitude. At the 14 TeV LHC, this signature can be probed with mediator masses as large as 1.5 TeV for a range of dark pion lifetimes, and the reach is increased further at the high-luminosity LHC. The emerging jet search is also sensitive to a broad class of long-lived phenomena, and we show this for a supersymmetric model with R-parity violation. Possibilities for discovery at LHCb are also discussed.

  16. Emerging Jets

    CERN Document Server

    Schwaller, Pedro; Weiler, Andreas

    2015-01-01

    In this work, we propose a novel search strategy for new physics at the LHC that utilizes calorimeter jets that (i) are composed dominantly of displaced tracks and (ii) have many different vertices within the jet cone. Such emerging jet signatures are smoking guns for models with a composite dark sector where a parton shower in the dark sector is followed by displaced decays of dark pions back to SM jets. No current LHC searches are sensitive to this type of phenomenology. We perform a detailed simulation for a benchmark signal with two regular and two emerging jets, and present and implement strategies to suppress QCD backgrounds by up to six orders of magnitude. At the 14 TeV LHC, this signature can be probed with mediator masses as large as 1.5 TeV for a range of dark pion lifetimes, and the reach is increased further at the high-luminosity LHC. The emerging jet search is also sensitive to a broad class of long-lived phenomena, and we show this for a supersymmetric model with R-parity violation. Possibilit...

  17. REVIEW OF WATER JET APPLICATIONS IN MANUFACTURING

    Directory of Open Access Journals (Sweden)

    Faruk MENDİ

    1999-02-01

    Full Text Available Usage of water jets in manufacturing processes, has been known for many decades. A wide range of engineering materials can be cut by water jets with satisfactory results. Enhanced reliability and efficiency of the technique, have yielded the technology greater interest for manufacturing applications. Water jets are used to cut soft materials such as wood, plastics, aluminium and copper. Abrasive water jets are used to cut very hard materials such as titanium, inconel, glass and ceramics. It is impossible to cut these materials with classical cutting technics. A water jet processing system utilises water pressure in the range of 100Mpa-400Mpa, for the different applications. In abrasive water jet milling and abrasive water jet cutting processes, the pressure of the jet is about 400Mpa. In water jet surface penning, the jet pressure is about 100Mpa. The process of abrasives mixing with the water stream is a complex phenomena. Erosion processes involved in cutting not yet fully understood. The lack of understanding the process call for other strategies in finding appropriate ways to obtain a precision depth in cutting operation. In this paper the principles of water jet systems had been explained. Results of experiments that made on cutting process and surface strengthening with water jet had been given.

  18. WIND TUNNEL TESTS OF TURBOPROP ENGINE CHARACTERISTICS DURING BIRD INGESTION,

    Science.gov (United States)

    TURBOPROP ENGINES, * INGESTION (ENGINES), BIRDS, BIRDS, DEGRADATION, TEST METHODS, AVIATION SAFETY, TAKEOFF, HAZARDS, JET ENGINE INLETS, DUCT INLETS, TURBINE COMPONENTS, DAMAGE, PHOTOGRAPHS, TURBINE BLADES.

  19. Economic assessment of proposed electric-discharge non-thermal plasma field-pilot demonstration units for NO{sub x} removal in jet-engine exhaust: White paper for SERDP Project CP-1038

    Energy Technology Data Exchange (ETDEWEB)

    Rosocha, L.A. [Los Alamos National Lab., NM (United States); Chang, J.S.; Urashima, Kuniko; Kim, S.J. [McMaster Univ. (Canada); Miziolek, A.W. [Army Research Lab. (United States)

    1999-01-05

    This project is currently evaluating non-thermal plasma (NTP) technologies for treating jet-engine exhaust arising from DoD test facilities. In the past, some economic analyses for NTP de-NO{sub x} have shown that it is not economical, compared to other techniques. The main reasons for this conclusion was that the previous analyses examined stand-alone, or less mature electrical-discharge reactors, or electron-beam based systems that incorporated both chemical additives and quite expensive electron accelerators. Also, in contrast to more recent developments, both the discharge and electron-beam techniques of the past did not extensively incorporate methods to increase the yields of active NO{sub x}-decomposing species. In an earlier White paper and a Project Report, the authors have analyzed the costs of more mature NTP systems incorporating chemical additives and new-concept NTP technologies for jet-engine emissions control and have shown lower exhaust-gas treatment costs for NTP systems compared to baseline standard de-NO{sub x} technologies like Selective Catalytic Reduction (SCR) combined with a wet scrubber or SCR combined with an electrostatic precipitator (ESP). In this paper, the authors will examine their most-promising candidate NTP reactor systems for a field-pilot demonstration on jet-engine exhaust and discuss the economic analyses for these hybrid units, which show that the economics of the proposed candidate systems are more favorable than earlier NTP reactor economic-assessment conclusions for NO{sub x} removal.

  20. Development of stratified-charge engine by impingement of fuel jet. ; Test results with gasoline fuel. Chokufunshiki shototsu kakusan sojo kyuki kikan no kaihatsu. ; Gasoline nenryo ni yoru jikken kekka

    Energy Technology Data Exchange (ETDEWEB)

    Kato, S.; Onishi, S. (Japan Clean Engine Lab. Co. Ltd., Ishikawa (Japan))

    1991-04-25

    Development was made of direct fuel injection stratified-charge method (OSKA nethod), to make the mixture formation in the direct fuel injection engine by having fuel jet positively impinge on the impingement part, installed in the combustion chamber. In the present report, the following conclusion was obtained through experiment on gasoline fuel by a single cylinder engine with a spark ignition method, combined with the OSKA method: High compressive ratio was made adoptable by applying an OSKA method, using a single hole nozzle with low opening pressure. Due to feed air swirl, made unnecessary for the mixture formation, adoption of early injection under the high load, etc., the highest brake mean effective pressure attained to 1.04MPa, which is almost equivalent to that of carburetor type automobile gasoline engine, while the highest brake thermal efficiency did to 37.7%, which is so to that of direct fuel injection diesel engine, equal in volume. Also under the low load, obtained was a high thermal efficiency, nearing that of diesel engine. 8 refs., 9 figs., 2 tabs.

  1. Wear analysis of diesel-engine fuel-injection pumps from military ground equipment fueled with Jet A-1. Interim report Jan-May 91

    Energy Technology Data Exchange (ETDEWEB)

    Lacey, P.I.

    1991-05-01

    The U.S. Department of Defense has adopted the single fuel for the battlefield concept. During Operation Desert Shield/Storm, Jet A-1 replaced diesel in many applications. A simultaneous increase in fuel injection pump failures was observed during that operation. Prior to its introduction, a number of studies had indicated that JP-8 is compatible with the current fleet of ground equipment. This report forms part of an ongoing study to define the fuel lubricity requirements of ground equipment. The report also details the wear and failure mechanisms observed from used pumps. The results indicate that, although Jet A-1 does increase wear, many other failure mechanisms are also prevalent.

  2. Parsec-Scale Jets and Tori in Seyfert Galaxies

    CERN Document Server

    Roy, A L; Wilson, A S; Ulvestad, J S; Norris, R P; Mundell, C G; Krichbaum, T P; Falcke, H; Colbert, E J M

    2000-01-01

    What causes the dichotomy between very powerful and very weak radio emission from AGNs? Perhaps the engines are the same but the jets get disrupted by dense ISM in radio-quiet objects, or else the engines are intrinsically different with jet power scaling with, say, black hole spin. To distinguish, one can look for interaction between the jets and the NLR and measure the jet speed close to the core using VLBI, before environmental effects become important. We find that in radio-quiet AGN, the jets appear slower and have a greater tendency to bend, and that one-sidedness and flat-spectrum cores are probably due to obscuration.

  3. Jet Quenching via Jet Collimation

    CERN Document Server

    Casalderrey-Solana, Jorge; Wiedemann, Urs Achim

    2011-01-01

    The ATLAS Collaboration recently reported strong modifications of dijet properties in heavy ion collisions. In this work, we discuss to what extent these first data constrain already the microscopic mechanism underlying jet quenching. Simple kinematic arguments lead us to identify a frequency collimation mechanism via which the medium efficiently trims away the soft components of the jet parton shower. Through this mechanism, the observed dijet asymmetry can be accomodated with values of $\\hat{q}\\, L$ that lie in the expected order of magnitude.

  4. The effect of injection pressure on spread of the jet, formation of the mixture and engine parameters of a direct injection Diesel engine. Einfluss des Einspritzdruckes auf Strahlausbreitung, Gemischbildung und Motorkennwerte eines direkt einspritzenden Dieselmotors

    Energy Technology Data Exchange (ETDEWEB)

    Binder, K.

    1992-07-31

    By increasing the injection pressure, the air/fuel ratio in the fuel jet is raised. The increased air supply in the injected jet, together with a drop spectrum displaced in the direction of smaller fuel drops leads to a quicker evaporation of the fuel. As the injection retardation is simultaneously reduced, one can achieve lower emission of nitrogen oxide without disadvantage in the fuel consumption. (orig./HW).

  5. On the Composition of GRBs' Collapsar Jets

    OpenAIRE

    Bromberg, Omer; Granot, Jonathan; Piran, Tsvi

    2014-01-01

    The duration distribution of long Gamma Ray Bursts reveals a plateau at durations shorter than ~20 s (in the observer frame) and a power-law decline at longer durations (Bromberg et al., 2012). Such a plateau arises naturally in the Collapsar model. In this model the engine has to operate long enough to push the jet out of the stellar envelope and the observed duration of the burst is the difference between the engine's operation time and the jet breakout time. We compare the jet breakout tim...

  6. The electrical conductivity of jet fuels F–34 and F–35 (JET A–1 in distribution

    Directory of Open Access Journals (Sweden)

    Białecki Tomasz

    2015-12-01

    Full Text Available The paper presents a changeability of electrical conductivity of jet fuels in distribution. Author described the methods used to prevent the formation of the dangers of static electricity. Research was carried out on two basic fuels used worldwide to power engines in civil (Jet A – 1 and military aircrafts (F – 34, during real fuel supplies in aviation military unit. Results of influence of temperature on the electrical conductivity of jet fuel are presented.

  7. Comparison of neurotoxic effects and potential risks from oral administration or ingestion of tricresyl phosphate and jet engine oil containing tricresyl phosphate.

    Science.gov (United States)

    Mackerer, C R; Barth, M L; Krueger, A J; Chawla, B; Roy, T A

    1999-07-09

    Neurotoxicity of tricresyl phosphates (TCPs) and jet engine oil (JEO) containing TCPs were evaluated in studies conducted in both rat and hen. Results for currently produced samples ("conventional" and "low-toxicity") were compared with published findings on older samples to identify compositional changes and relate those changes to neurotoxic potential. Finally, a human risk assessment for exposure by oral ingestion of currently produced TCPs in JEO at 3% (JEO + 3%) was conducted. TCPs and certain other triaryl phosphates administered as single doses inhibited brain neuropathy target esterase (B-NTE; neurotoxic esterase) in the rat and the hen (hen 3.25 times as sensitive), and both species were deemed acceptable for initial screening purposes. Neither rat nor hen was sensitive enough to detect statistically significant inhibition of B-NTE after single doses of IEO + 3% "conventional" TCP. Subacute administration of 2 g/kg/d of JEO + 3% "conventional" TCP to the hen produced B-NTE inhibition (32%), which did not result in organophosphorus-induced delayed neurotoxicity (OPIDN). Subchronic administration of JEO + 3% TCP but not JEO + 1% TCP at 2 g/kg/d produced OPIDN. Thus, the threshold for OPIDN was between 20 and 60 mg "conventional" TCP/kg/d in JEO for 10 wk. The current "conventional" TCPs used in JEO and new "low-toxicity" TCPs now used in some JEO are synthesized from phenolic mixtures having reduced levels of ortho-cresol and ortho-xylenols resulting in TCPs of very high content of meta- and para-substituted phenyl moieties; this change in composition results in lower toxicity. The "conventional" TCPs still retain enough inhibitory activity to produce OPIDN, largely because of the presence of ortho-xylyl moieties; the "low-toxicity" TCPs are largely devoid of ortho substituents and have extremely low potential to cause OPIDN. The TCPs produced in the 1940s and 1950s were more than 400 times as toxic as the "low-toxicity" TCPs produced today. Analysis of the

  8. Dichotomy of Solar Coronal Jets: Standard Jets and Blowout Jets

    Science.gov (United States)

    Moore, R. L.; Cirtain, J. W.; Sterling, A. C.; Falconer, D. A.

    2010-01-01

    By examining many X-ray jets in Hinode/XRT coronal X-ray movies of the polar coronal holes, we found that there is a dichotomy of polar X-ray jets. About two thirds fit the standard reconnection picture for coronal jets, and about one third are another type. We present observations indicating that the non-standard jets are counterparts of erupting-loop H alpha macrospicules, jets in which the jet-base magnetic arch undergoes a miniature version of the blowout eruptions that produce major CMEs. From the coronal X-ray movies we present in detail two typical standard X-ray jets and two typical blowout X-ray jets that were also caught in He II 304 Angstrom snapshots from STEREO/EUVI. The distinguishing features of blowout X-ray jets are (1) X-ray brightening inside the base arch in addition to the outside bright point that standard jets have, (2) blowout eruption of the base arch's core field, often carrying a filament of cool (T 10(exp 4) - 10(exp 5) K) plasma, and (3) an extra jet-spire strand rooted close to the bright point. We present cartoons showing how reconnection during blowout eruption of the base arch could produce the observed features of blowout X-ray jets. We infer that (1) the standard-jet/blowout-jet dichotomy of coronal jets results from the dichotomy of base arches that do not have and base arches that do have enough shear and twist to erupt open, and (2) there is a large class of spicules that are standard jets and a comparably large class of spicules that are blowout jets.

  9. Conversion of a Micro, Glow-Ignition, Two-Stroke Engine from Nitromethane-Methanol Blend Fuel to Military Jet Propellant (JP-8)

    Science.gov (United States)

    2012-01-01

    section of air intake assembly solid model; shows hot-wire anemometer probe orientation and venturi shape [25...it the weak link. Added machined flat to motor shaft and a #6-32 UNC cup -point setscrew to coupler on motor end. 2 Coupler spins up threaded...engine shaft Having fixed the motor end, engine end became the weak link. Added machined flat to engine shaft and a #8-32 UNC cup -point setscrew

  10. Impingement jet cooling in gas turbines

    CERN Document Server

    Amano, R S

    2014-01-01

    Due to the requirement for enhanced cooling technologies on modern gas turbine engines, advanced research and development has had to take place in field of thermal engineering. Impingement jet cooling is one of the most effective in terms of cooling, manufacturability and cost. This is the first to book to focus on impingement cooling alone.

  11. 某小型涡喷发动机空中停车故障分析%Failure Analysis of A Small Turbo-Jet Engine Power off During Flight

    Institute of Scientific and Technical Information of China (English)

    阳再清; 欧阳中辉; 吕晓林

    2013-01-01

    为解决某型无人机涡喷发动机在试飞中出现的空中停车问题,应用故障树分析方法进行故障分析。通过对涡喷发动机空中停车故障的分析,给出故障分析与定位的过程,提出相应改进措施,并进行验证。验证结果表明:故障树分析方法对故障归零分析、发动机典型故障处理等有较好的借鉴作用,可为发动机研究和应用者提供参考。%In order to solve the breakdown problem of a certain type of UAV during testing flight, the method of failure tree analysis is used to analyze the fault. Based on the analysis of the breakdown of a turbo-jet engine during testing flight, the analysis and location process of the breakdown problem is provided, corresponding improving measures have been raised and verified. The result shows that it is a good reference to the analysis of failure to zero and the disposal of typical failure of the engine and for the engine designers and users.

  12. Problems of providing completeness of the methane-containing block-jet combustion in a rocket-ramjet engine's combustion chamber

    Science.gov (United States)

    Timoshenko, Valeriy I.; Belotserkovets, Igor S.; Gusinin, Vjacheslav P.

    2009-11-01

    Some problems of methane-containing hydrocarbon fuel combustion are discussed. It seems that reduction of methane burnout zone length is one from main problems of designing new type engine. It is very important at the creation of combustion chambers of a rocket-ramjet engine for prospective space shuttle launch vehicles.

  13. Siegel FIRST EXPERIMENTAL DISCOVERY of Granular-Giant-Magnetoresistance (G-GMR) DiagnosES/ED Wigner's-Disease/.../Spinodal-Decomposition in ``Super''Alloys Generic Endemic Extant in: Nuclear-Reactors/ Petrochemical-Plants/Jet/ Missile-Engines/...

    Science.gov (United States)

    Hoffman, Ace; Wigner-Weinberg, Eugene-Alvin; Siegel, Edward Carl-Ludwig Sidney; ORNL/Wigner/Weinberg/Siegel/Hollifeld/Yu/... Collaboration; ANL/Fermi/Wigner/Arrott/Weeks/Bader/Freeman/Sinha/Palazlotti/Nichols/Petersen/Rosner/Zimmer/... Collaboration; BNL/Chudahri/Damask/Dienes/Emery/Goldberg/Bak//Bari/Lofaro/... Collaboration; LLNL-LANL/Hecker/Tatro/Meara/Isbell/Wilkins/YFreund/Yudof/Dynes/Yang/... Collaboration; WestinKLouse/EPRI/PSEG/IAEA/ABB/Rickover/Nine/Carter/Starr/Stern/Hamilton/Richards/Lawes/OGrady/Izzo Collaboration

    2013-03-01

    Siegel[APS Shock-Physics Mtg., Chicago(11)] carbides solid-state chemistry[PSS (a)11,45(72); Semis. & Insuls. 5: 39,47,62 (79)], following: Weinberg-Siegel-Loretto-Hargraves-Savage-Westwood-Seitz-Overhauser-..., FIRST EXPERIMENTAL DISCOVERY of G-GMR[JMMM 7, 312(78); Google: ``If LEAKS Could KILL Ana Mayo''] identifIED/IES GENERIC ENDEMIC EXTANT domination of old/new (so mis-called) ``super''alloys': nuclear-reactors/spent-fuel-casks/refineries/jet/missile/rocket-engines in austenitic/FCC Ni/Fe/Co-based (so mis-called) ''super''alloys (182/82; Hastelloy-X,600,304/304L-Stainless-Steels,...,690!!!) GENERIC ENDEMIC EXTANT detrimental(synonyms!!!): THERMAL: Wigner's-disease(WD physics) [J.Appl.Phys.17,857(46)]/ Ostwald-ripening

  14. Anti-corrosion properties of Ni-P alloy coated on engine cylinder prepared from jet electrodeposion%发动机气缸电喷镀镍磷合金镀层及耐腐蚀性能

    Institute of Scientific and Technical Information of China (English)

    王颖; 康敏; 傅秀清; 王兴盛

    2014-01-01

    Cylinder is the important part of tractor engine, which service life and the production cost are directly affected by anti-corrosion of the component. With the excellent wear resistance, corrosion resistance and higher hardness, Ni-P alloy deposited layer plays an important role for enhance the service life and reliability of cylinder, and the capability and quality of the tractor engine can be improved. Because of severe working environment of cylinder and piston such as high temperature, high load, high-velocity motion, poor lubrication, difficult cooling, especially weak acid for work environment, it is advisable to study the anti-corrosion properties of Ni-P alloy coated on engine cylinder. However, with the advancement of social economy, the conventional method for electrodeposited Ni-P alloy fails to meet the requirements of the development due to lower depositing rate and lower production efficiency. The jet electrodeposition is developed in recent years, which can significant increase the production efficiency because jet electrolyte can accelerate transfer process of the electrodeposition material and augment limiting current density. So the jet electrodeposition is a kind of high-velocity, selective electrodeposition technique with high deposition current density. In this paper, the engine cylinder coated with Ni-P alloy with jet electrodeposition was taken as research object. The surface appearance of deposited layer was observed by 6XB-PC reflective optical microscope. The corrosion behavior of Ni-P alloy coated on cylinder in 50 g/L NaCl solutions at different moment was studied by electrochemical impedance spectroscopy and potentiodynamic polarization method. The results show that the coating surface appearance is dense and smooth. Electrochemical impedance spectroscopy is composed of high and low frequency arcs when the layer immersed in 50 g/L NaCl solutions with 0.5, 1, 6, 12 and 24 h. The high frequency arcs have relation with original oxidation

  15. Boundary Shear Acceleration in the Jet of MKN501

    CERN Document Server

    Sahayanathan, S

    2009-01-01

    The high resolution image of the jet of the BL Lac object MKN501 in radio, show a limb-brightened feature. An explanation of this feature as an outcome of differential Doppler boosting of jet spine and jet boundary due to transverse velocity structure of the jet requires large viewing angle. However this inference contradicts with the constraints derived from the high energy $\\gamma$-ray studies unless the jets bends over a large angle immediately after the $\\gamma$-ray zone (close to the central engine). In this letter we propose an alternate explanation to the limb-brightened feature of MKN501 by considering the diffusion of electrons accelerated at the boundary shear layer into the jet medium and this consideration does not require large viewing angle. Also the observed difference in the spectral index at the jet boundary and jet spine can be understood within the frame work of shear acceleration.

  16. Inclusive Jets in PHP

    Science.gov (United States)

    Roloff, P.

    Differential inclusive-jet cross sections have been measured in photoproduction for boson virtualities Q^2 < 1 GeV^2 with the ZEUS detector at HERA using an integrated luminosity of 300 pb^-1. Jets were identified in the laboratory frame using the k_T, anti-k_T or SIScone jet algorithms. Cross sections are presented as functions of the jet pseudorapidity, eta(jet), and the jet transverse energy, E_T(jet). Next-to-leading-order QCD calculations give a good description of the measurements, except for jets with low E_T(jet) and high eta(jet). The cross sections have the potential to improve the determination of the PDFs in future QCD fits. Values of alpha_s(M_Z) have been extracted from the measurements based on different jet algorithms. In addition, the energy-scale dependence of the strong coupling was determined.

  17. Combustion and emission characteristics of jet controlled compression ignition engine at different loads%射流控制压缩着火发动机不同负荷下燃烧及排放特性

    Institute of Scientific and Technical Information of China (English)

    张强; 杨培源; 隆武强; 田江平

    2016-01-01

    针对柴油预混合气着火相位难以直接控制的问题,提出射流控制压缩着火(jet controlled compression ignition, JCCI)方式。将一台单缸农用柴油机改造为JCCI发动机:压缩比降至12,增加一个带液化石油气(liquefied petroleum gas, LPG)供给通道和火花塞的点火室,并进行了JCCI发动机全负荷特性试验研究。试验结果表明:采用射流控制压缩着火方式可以有效控制发动机的燃烧相位和排放。在平均有效压力低于0.44 MPa的工况范围,NOx排放比原机降低较多,燃烧始点相位CA10与滞燃期几乎不随负荷增加而改变;在平均有效压力高于0.44直至0.54 MPa负荷范围内,燃烧始点相位迅速前移,滞燃期迅速减小,柴油提前自燃,射流对着火相位控制作用减弱,NOx排放迅速增加并超过原机;在全负荷范围,烟度始终维持在低水平,HC和CO排放较高。该研究可为柴油预混合燃烧着火相位控制提供参考。%One of the key points in diesel premixed combustion is the realization of combustion phasing control. The sensitivity of diesel to temperature and equivalent ratio was the crucial obstacle. In order to directly control the diesel premixed combustion phasing, a novel method called the jet controlled compression ignition (JCCI) for diesel premixed compression ignition was proposed. A single cylinder diesel engine was modified to study the JCCI system. First, a small ignition chamber comprising a gas fuel injector and a spark plug was mounted on the cylinder head in this diesel engine. Six small orifices were used to connect the ignition chamber and the main chamber. Furthermore, the compression ratio was reduced to 12 to avoid the auto-ignition of the premixed diesel fuel. Experiments were conducted on the JCCI engine under overall loads at a constant speed to study the trend of combustion and the emission characteristics of JCCI system. The results showed that

  18. Altitude Test Chamber Investigation of Performance of a 28-inch Ram-jet Engine II : Effects of Gutter Width and Blocked Area on Operating Range and Combustion Efficiency

    Science.gov (United States)

    Shillito, T B; Jones, W L; Kahn, R W

    1950-01-01

    Altitude-test-chamber investigation of effects of flame-holder blocked area and gutter width on performance of 28-inch diameter ram jet at simulated flight Mach number of 2.0 for altitudes from 40,000 to 55,000 feet was conducted at NACA Lewis laboratory. Ten flame holders investigated covered gutter widths from 1.00 to 2.50 inches and blocked areas from 40.5 to 62.0 percent of combustion-chamber area. Gutter width did not appreciably affect combustion efficiency. Increase in blocked area from 40 to 62 percent resulted in 5- to 10-percent increase in combustion efficiency. Increasing gutter width resulted in improvement in fuel-air-ratio operating range.

  19. The Giant Jet

    Science.gov (United States)

    Neubert, T.; Chanrion, O.; Arnone, E.; Zanotti, F.; Cummer, S.; Li, J.; Füllekrug, M.; van der Velde, O.

    2012-04-01

    Thunderstorm clouds may discharge directly to the ionosphere in spectacular luminous jets - the longest electric discharges on our planet. The electric properties of jets, such as their polarity, conductivity, and currents, have been predicted by models, but are poorly characterized by measurements. Here we present an analysis of the first gigantic jet that with certainty has a positive polarity. The jet region in the mesosphere was illuminated by an unusual sprite discharge generated by a positive cloud-to-ground lightning flash shortly after the onset of the jet. The sprite appeared with elements in a ring at ~40 km distance around the jet, the elements pointing curving away from the jet. This suggests that the field close the jet partially cancels the field driving the sprite. From a simple model of the event we conclude that a substantial portion of the positive cloud potential must be carried to ~50 km altitude, which is also consistent with the observed channel expansion and the electromagnetic radiation associated with the jet. It is further shown that blue jets are likely to substantially modify the free electron content in the lower ionosphere because of increased electron attachment driven by the jet electric field. The model further makes clear the relationship between jets, gigantic jets, and sprites. This is the first time that sprites are used for sounding the properties of the mesosphere. The observations presented here will allow evaluation of theories for jet and gigantic jet generation and of their influence on the atmosphere-ionosphere system.

  20. Advanced thermally stable jet fuels

    Energy Technology Data Exchange (ETDEWEB)

    Schobert, H.H.

    1999-01-31

    The Pennsylvania State University program in advanced thermally stable coal-based jet fuels has five broad objectives: (1) Development of mechanisms of degradation and solids formation; (2) Quantitative measurement of growth of sub-micrometer and micrometer-sized particles suspended in fuels during thermal stressing; (3) Characterization of carbonaceous deposits by various instrumental and microscopic methods; (4) Elucidation of the role of additives in retarding the formation of carbonaceous solids; (5) Assessment of the potential of production of high yields of cycloalkanes by direct liquefaction of coal. Future high-Mach aircraft will place severe thermal demands on jet fuels, requiring the development of novel, hybrid fuel mixtures capable of withstanding temperatures in the range of 400--500 C. In the new aircraft, jet fuel will serve as both an energy source and a heat sink for cooling the airframe, engine, and system components. The ultimate development of such advanced fuels requires a thorough understanding of the thermal decomposition behavior of jet fuels under supercritical conditions. Considering that jet fuels consist of hundreds of compounds, this task must begin with a study of the thermal degradation behavior of select model compounds under supercritical conditions. The research performed by The Pennsylvania State University was focused on five major tasks that reflect the objectives stated above: Task 1: Investigation of the Quantitative Degradation of Fuels; Task 2: Investigation of Incipient Deposition; Task 3: Characterization of Solid Gums, Sediments, and Carbonaceous Deposits; Task 4: Coal-Based Fuel Stabilization Studies; and Task 5: Exploratory Studies on the Direct Conversion of Coal to High Quality Jet Fuels. The major findings of each of these tasks are presented in this executive summary. A description of the sub-tasks performed under each of these tasks and the findings of those studies are provided in the remainder of this volume

  1. Replace the Carburetor Diaphragm. Pulsa-Jet Style with Automatic Choke. Fuel System. Student Manual 2. Small Engine Repair Series. First Edition.

    Science.gov (United States)

    Hill, Pamela

    This student manual, part of a small-engine repair series on servicing fuel systems, is designed for use by special needs students in Texas. The manual explains in pictures and short sentences, written on a low reading level, the job of replacing carburetor diaphragms. Along with the steps of this repair job, specific safety and caution…

  2. Process parameters optimization of increasing depositing rate for jet electrodeposition of engine cylinder%提高发动机气缸电喷镀沉积速度的工艺优化

    Institute of Scientific and Technical Information of China (English)

    王颖; 康敏; 陈超; 杨勇; 傅秀清

    2013-01-01

    The cylinder is an extremely important easily wearing part of a tractor engine, whose service life and production cost are directly affected by the wear resistance of the component. With excellent wear resistance, corrosion resistance, and greater hardness, a Ni-P alloy deposited layer can significantly enhance the service life and reliability of the cylinder, and the capability and quality of the tractor engine can be improved. The lower limiting current density of the traditional electrodeposited Ni-P alloy method leads to a lower depositing rate and lower production efficiency. Jet electrodeposition has been developed in recent years, which can significant increase the depositing rate because the jet electrolyte can accelerate the transfer process of the electrodeposition material and augment limiting current density. So jet electrodeposition is a type of high-velocity, selective electrodeposition technique with high deposition current density and high velocity. Furthermore, optimization of the process parameters of jet electrodeposition is the way to further increase the depositing rate. In this paper, technological experimentation is investigated by using a custom design of JMP to optimize process parameters of jet electrodeposition. The JMP software is Six Sigma statistical software developed by SAS, which is a professional statistical analysis tool. The JMP software can be used for processing data and designing of experiments. To the best of our knowledge, there is currently no report about applications of JMP in electrochemical use domestically. Voltage, electrolyte temperature, dipolar space, flow velocity of electrolyte, and dipolar relative velocity are the influence factors, and the depositing rate of deposited layers is the experimental index, and the relationships between the experimental index and the influence factors are analyzed through the response surface analysis method and sub-stepping method. The quadratic regression mathematical models that

  3. Editorial on Future Jet Technologies

    Science.gov (United States)

    Gal-Or, Benjamin

    2014-08-01

    Advanced jet engines do not operate in an application vacuum. Their optimal use in advanced military applications drives much of their basic innovative research and development, especially when new needs arise in the rapidly changing domains of stealth-agile, fighter aircraft and tailless-stealth, Jet-Steered, Unmanned Air Vehicles (JS-UAV). For these reasons we periodically update this Journal with new trends that affect, and sometimes control, research and development of future jet-engines. One relevant example is the recently unmasked RQ-180 stealth-tailless drone, which is an improved version of the smaller, RQ-170 captured by Iran. Most important, with the new X-47B/C tailless-stealth JS-UAV, it is to dominate future uses of fuel-efficient jet-engines, especially for operating in dusty environments. The RQ-180 has been secretly designed and funded since 2008. It is based on a classified, 1986, parent Israeli Patents 78402, which protect hundreds design and testing trade secrets taken from 1986 to 1997 by the United States Government (USG) via classified contracts with USG-Contractors Boeing, Lockheed, General Dynamics and General Electric, as revealed by a December 6, 2013 Aviation Week [1-3] and U.S. Court of Appeals for the Federal Circuit, Case 2014-5028, Docket 12 [4]. The new RQ-180 design explains the recent U.S. Air Force ISR shift away from "permissive" environments - such as Iraq and Afghanistan, where non-stealthy Global Hawk and General Atomics' Reaper operate - toward new missions in highly "contested" or strongly "denied" enemy airspaces.

  4. Improvement of emissions and performance by using of air jet, exhaust gas re-circulation and insulation methods in a direct injection diesel engine

    Directory of Open Access Journals (Sweden)

    Jafarmadara S.

    2013-01-01

    Full Text Available This article investigates the improvement of operation characteristics and emissions reduction by means of creating an air-cell inside the piston body, exhaust gases recirculating and insulating combustion chamber in a direct injection diesel engine simultaneously. The engine considered is a caterpillar 3401 which was modeled with an air-cell included as part of the piston geometry. This air-cell demonstrates that air injection in late combustion period can be effective in a significant reduction of Soot emission while cold EGR can be effective in reduction of NOx emission. Also for increasing of performance parameters, combustion chamber with air-cell is insulated. The analyses are carried out at part (75% of full load and full load conditions at the same engine speed 1600 rpm. The obtained results indicate that creating the air-cell has a slight effect on improvement of performance parameters and it has significantly effect on Soot reduction. The air-cell decreases the Soot pollutant as a factor of two at both part and full load conditions. Also, the adding 5% of cold EGR in inlet air decreases NOx by about half and insulating the engine increases the power and IMEP by about 7.7% and 8.5% and decreases the ISFC by about 7.5% at part load and increases power and IMEP by 8.5%, 8.5% and decreases ISFC by 8% at full load condition, respectively. Using this method, it was possible to control emissions formation and increase performance parameters simultaneously. The predicted results for mean in-cylinder pressure and emissions are compared to the corresponding experimental results and show good agreements.

  5. Two-component Jets and the Fanaroff–Riley Dichotomy

    NARCIS (Netherlands)

    Meliani, Z.; Keppens, R.

    2011-01-01

    The two types of Fanaroff–Riley radio loud galaxies, FRI and FRII, exhibit strong jets but with different properties. These differences may be associated to the central engine and/or the external medium. The AGN classification FRI and FRII can be linked to the transverse stratification of the jet. I

  6. Causality and stability of cosmic jets

    CERN Document Server

    Porth, O

    2014-01-01

    In stark contrast to their laboratory and terrestrial counterparts, the cosmic jets appear to be very stable. The are able to penetrate vast spaces, which exceed by up to a billion times the size of their central engines. We propose that the reason behind this remarkable property is the loss of causal connectivity across these jets, caused by their rapid expansion in response to fast decline of external pressure with the distance from the "jet engine". In atmospheres with power-law pressure distribution, the total loss of causal connectivity occurs, when the power index k>2 - the steepness which is expected to be quite common for many astrophysical environments. This conclusion does not seem to depend on the physical nature of jets - it applies both to relativistic and non-relativistic flows, both magnetically-dominated and unmagnetized jets. In order to verify it, we have carried out numerical simulations of moderately magnetized and moderately relativistic jets. Their results give strong support to our hypo...

  7. On the Composition of GRBs' Collapsar Jets

    CERN Document Server

    Bromberg, Omer; Piran, Tsvi

    2014-01-01

    The duration distribution of long Gamma Ray Bursts reveals a plateau at durations shorter than ~20 s (in the observer frame) and a power-law decline at longer durations (Bromberg et al., 2012). Such a plateau arises naturally in the Collapsar model. In this model the engine has to operate long enough to push the jet out of the stellar envelope and the observed duration of the burst is the difference between the engine's operation time and the jet breakout time. We compare the jet breakout time inferred from the duration distribution (~10 s in the burst's frame) to the breakout time of a hydrodynamic jet (~10 s for typical parameters) and of a Poynting flux dominated jet with the same overall energy (<~1 s). As only the former is compatible with the duration of the plateau in the GRB duration distribution, we conclude that the jet is hydrodynamic during most of the time that its head is within the envelope of the progenitor star and around the time when it emerges from the star. This would naturally arise i...

  8. Study of Water Jet Impulse in Water-Jet Looms

    Institute of Scientific and Technical Information of China (English)

    LI Ke-rang; MA Wei-wei; CHEN Ming

    2005-01-01

    The water jet impulse is brought forward to study the traction force of the water jet to the flying weft in water-jet looms. The distribution of the water jet impulse in the shed is tested by a sensor, and the influence of water jet parameters on the water jet impulse is analyzed.

  9. Bouncing and Merging of Liquid Jets

    Science.gov (United States)

    Saha, Abhishek; Li, Minglei; Law, Chung K.

    2014-11-01

    Collision of two fluid jets is a technique that is utilized in many industrial applications, such as in rocket engines, to achieve controlled mixing, atomization and sometimes liquid phase reactions. Thus, the dynamics of colliding jets have direct impact on the performance, efficiency and reliability of such applications. In analogy with the dynamics of droplet-droplet collision, in this work we have experimentally demonstrated, for n-alkane hydrocarbons as well as water, that with increasing impact inertia obliquely colliding jets also exhibit the same nonmonotonic responses of merging, bouncing, merging again, and merging followed by disintegration; and that the continuous entrainment of the boundary layer air over the jet surface into the colliding interfacial region leads to two distinguishing features of jet collision, namely: there exists a maximum impact angle beyond which merging is always possible, and that merging is inhibited and then promoted with increasing pressure. These distinct response regimes were mapped and explained on the bases of impact inertia, deformation of the jet surface, viscous loss within the jet interior, and the thickness and pressure build-up within the interfacial region in order to activate the attractive surface van der Waals force to effect merging.

  10. Spectra and power of relativistic jets

    CERN Document Server

    Ghisellini, G

    2003-01-01

    The power of blazar jets rivals the power that gravity can extract from accreting matter. The mechanism launching and accelerating jets can be considered as the most efficient engine operating in radio--loud sources. It is still a matter of debate if the jet carries this power to the radio lobes, hundreds of kpc away, in the form of Poynting flux or bulk kinetic energy, or both, and if these two ingredients have relative weights changing along the way. Accordingly, there are two (or more) possible general scenarios for how the jet can dissipate part of its power into radiation. It can be through e.g. reconnection of the magnetic field in the purely electromagnetic scenario, or through internal shocks in the matter dominated picture. Ways to discriminate these ideas are welcome.

  11. Quantitative analysis of schlieren photographs for internal combustion engine diagnostics. 2nd Report. ; Smoothing of background distortion and analytical results of transient wall-impinging jet. Nainen kikan ni okeru schlieren shashin no teiryoka gazo shoriho ni kansuru kenkyu. 2. ; Background no yugami jokyo, narabini hiteijo hekimen shototsu funryu no kaiseki kekka

    Energy Technology Data Exchange (ETDEWEB)

    Ouchi, H.; Chikahisa, T.; Murayama, T. (Hokkaido Univ., Sapporo (Japan). Faculty of Engineering)

    1991-02-25

    It was previously reported, for the research on the internal combustion engine, that the quantitative analysis of Schlieren photographs, one of simple visualization technologies, is effective on the heightening in accuracy of the analysis by Schlieren photographs and however, insufficient in countermeasures against the background distortion, causing errors. Then, by removing background distortion and analyzing Schlieren photographs, taken of transient wall-impinging jet, evaluation was made of the present quantitative analysis. As a result, a method could be shown to effectively correct the background distortion. Further, upon analyzing transient wall-impinging jet by that method, result could be obtained to be sufficiently accurate to grasp its structural characteristics. The resent quantitative analysis is advantageous in capability of, among others, monentarily quantify the two-dimensional phenomenon by a simple unit, and support the quantitative information for the Schlieren measurerment, widely used in the research on the internal combustion engine. 8 refs., 8 figs.

  12. Emission reduction in industrial gas turbines; Rolls-Royce modified a jet engine. Emissionssenkung bei Industriegasturbinen; Rolls-Royce modifizierte ein Flugtriebwerk

    Energy Technology Data Exchange (ETDEWEB)

    Welsh, D.

    1993-06-01

    Rolls Royce decided in 1989 to use its environmentally carefully technique of steam/water injection in the development of a new type of combustion process for its RB211 industrial gas turbine. This takes into account the ever stricter worldwide environment protection laws, which demand a reduction of the harmful waste gases from gas turbines used in the field of natural gas pumps and energy generation - an important market sector for Rolls Royce. The solution to this problem developed by this British firm aims at modifying the engine, which is known as a dry low emission system, and a simultaneous reduction of the NO[sub x] and CO emission. (orig.)

  13. Relativistic two-component jet evolutions in 2D and 3D

    NARCIS (Netherlands)

    Meliani, Z.; Keppens, R.

    2009-01-01

    Observations of astrophysical jets and theoretical arguments suggest a transverse stratification with two components induced by intrinsic features of the central engine (accretion disk + black hole). We study two-component jet dynamics for an inner fast low density jet, surrounded by a slower, dense

  14. Spectroscoping analysis of ignition in a spark ignition engine with jet-controlled combustion; Spektroskopische Untersuchung der Entflammung an einem Ottomotor mit strahlgefuehrtem Brennverfahren

    Energy Technology Data Exchange (ETDEWEB)

    Palaveev, S. [MOT Forschungs- und Entwicklungsgesellschaft fuer Motorentechnik, Optik und Thermodynamik GmbH, Karlsruhe (Germany); Buri, S.; Xander, B.; Spicher, U. [Karlsruhe Univ. (T.H.) (Germany). Inst. fuer Kolbenmaschinen

    2007-07-01

    The gasoline direct injection engine is one of the most promising strategies today to reduce the fuel consumption and CO{sub 2}-emissions of spark-ignition engines. The commercial launch of that combustion system was possible only through the development of new optical measurement techniques, which have been a major contribution for understanding the basics of the combustion in a stratified mode. In terms of space and time, compared to the homogeneous approach, the air-fuel-ratio for a stratified mode may vary significantly. This fluctuation affects in a critical way the process of ignition and combustion. The knowledge of the air-fuel-ratio in the spark plug area both at time of ignition and in during the combustion is therefore critical for the development of this combustion system and it components. This paper presents the spark-emission spectroscopy as a non invasive optical technique for measuring the air-fuel-ratio {lambda} in the spark gap at time of ignition. (orig.)

  15. Multi-Dimensional Modeling of the Effects of Air Jet and Split Injection on Combustion and Emission of DirectInjection Diesel Engine

    Directory of Open Access Journals (Sweden)

    Mehdi Mansury

    2016-01-01

    Full Text Available One of the most important problems in reducing the emissions of diesel engines is to exchange between the oxides of nitrogen and soot emissions. Fuel multiple injection and air injection into combustion chamber are among the most powerful tools to concurrent reduction of these two emissions. In this research, the effect of multiple injection and air injection on combustion and emission parameters has been studied by AVL fire computational fluid dynamic software. Six states of base and modified combustion chamber have been studied in two different injection patterns including 90 (25 10 and 75 (25 25 mods. Results show that concurrent applying of both multiple injection and air injection methods has resulted in simultaneous reduction of oxide nitrogen and soot pollutants and a negligible loss is seen in the operational parameters of engine. Compression between six studied cases show that the 90 (25 10 mode of injection with modified combustion chamber is the optimum mode by decreasing of soot and oxides of nitrogen emissions about 29% and 20% respectively and 6% indicated power loss in compression to the base combustion chamber and single injection mode. The obtained results from the computational fluid dynamic code have been compared with the existing results in the technical literature and show acceptable behavior.

  16. Prediction of impact response of reinforced concrete slabs subjected to impact of aircraft engine missile. Verification by the results of full-scale impact tests using real jet engine

    Energy Technology Data Exchange (ETDEWEB)

    Uchida, Takashi; Ohno, Tomonori [National Defence Academy, Yokosuka, Kanagawa (Japan)

    1995-05-01

    It is of importance to investigate and predict the response of reinforced concrete structures to impact loading from the view point of disaster prevention at nuclear power plant facilities, and there is an urgent requirement for establishment of design methods against the impact of aircraft and/or its engine. The authors proposed a numerical approach for assessing local response characteristics by the high-velocity impact of deformable missiles, and the results of numerical analyses were verified by that of full-scale impact tests using real engine body (GE-J79) reported by Muto et.al. The relation between the crash strength of engine body and the limit thickness of perforation was calculated and illustrated in this paper. (author).

  17. From heating sytems producer to engine experts. Gorleben: Dreyer und Bosse Kraftwerke GmbH becomes a specialist in ignition jet aggregates; Vom Heizungsbauer zum Motorexperten. In Gorleben entwickelt sich die Dreyer and Bosse Kraftwerke GmbH zum Spezialisten fuer Zuendstrahl-Aggregate

    Energy Technology Data Exchange (ETDEWEB)

    Hinsch, C.

    2001-07-01

    Peter Bosse and his team have been providers of cogeneration systems for biogas plants since 1999. Their range of systems today covers 70-kW ignition jet aggregates up to 625 kW spark ignition engines. [German] Seit 1999 baut Peter Bosse mit seinem Team in dem Wendland-Dorf Blockheizkraftwerke (BHKW) fuer Biogasanlagen, das Angebot reicht heute von 70-Kilowatt-Zuendstrahl-Aggregat bis zum 625-kW-Ottomotor. (orig.)

  18. Filament Eruptions, Jets, and Space Weather

    Science.gov (United States)

    Moore, Ronald; Sterling, Alphonse; Robe, Nick; Falconer, David; Cirtain, Jonathan

    2013-01-01

    -plasma component of coronal X-ray jets. This favors the idea that Type-II spicules are miniature counterparts of coronal X-ray jets. In Moore et al (2011, ApJ, 731, L18), we pointed out that if Type-II spicules are magnetic eruptions that work like coronal X-ray jets, they carry an area-averaged mechanical energy flux of approximately 7x10)(exp 5) erg cm(exp -2) s(exp-1) into the corona in the form of MHD waves and jet outflow, enough to power the heating of the global corona and solar wind. On this basis, from our observations of mini-filament eruptions in blowout X-ray jets, we infer that magnetic explosions of the type that have erupting filaments in them are the main engines of both (1) the steady solar wind and (2) the CMEs that produce the most severe space weather by blasting out through the corona and solar wind, making solar energetic particle storms, and bashing the Earth's magnetosphere. We conclude that in focusing on prominences and filament eruptions, Einar had his eye on the main bet for understanding what powers all space weather, both the extreme and the normal.

  19. Dual-use conversion of a high-Mach-number jet engine test cell for industrial gas turbine low-emission combustor development

    Energy Technology Data Exchange (ETDEWEB)

    Pillsbury, P.W.; Ryan, W.R. [Westinghouse Electric Corp., Orlando, FL (United States); Moore, J.R. [Sverdrup Technology, Inc., Arnold AFB, TN (United States). AEDC Group

    1997-01-01

    With the recent trend of reducing US military expenditures, it has become desirable to develop dual use of certain Department of Defense facilities. These efforts have a commercial purpose, while still retaining a military benefit. The goals of these efforts are to make US business more competitive in world markets, to develop the technology to solve pressing national problems, and to maintain intact the necessary talent pool and equipment for possible military needs. In a recent initiative described in this paper, test cell equipment at the Arnold Engineering Development Center, Arnold AFB, Tennessee, was modified and expanded to allow development by the Westinghouse Electric Corporation of low-emission combustors for heavy-duty gas turbines for commercial power generation.

  20. Experiment on Conical Pick Cutting Rock Material Assisted with Front and Rear Water Jet

    Directory of Open Access Journals (Sweden)

    Xiaohui Liu

    2015-01-01

    Full Text Available Conical picks are one kind of cutting tools widely used in engineering machinery. In the process of rock breaking, the conical pick bears great cutting force and wear. To solve the problem, a new method, conical pick assisted with high pressure water jet, could break rock effectively, and four different configuration modes of water jet were presented. In this paper, based on the analysis of the different water jet configuration’s advantages and disadvantages, experiments on front water jet, new typed rear water jet, and the combination of those two water jet configuration modes were conducted to study the assisting cutting performance and obtain the quantitative results.

  1. Acceleration of Compact Radio Jets on Sub-parsec Scales

    Science.gov (United States)

    Lee, Sang-Sung; Lobanov, Andrei P.; Krichbaum, Thomas P.; Zensus, J. Anton

    2016-08-01

    Jets of compact radio sources are highly relativistic and Doppler boosted, making studies of their intrinsic properties difficult. Observed brightness temperatures can be used to study the intrinsic physical properties of relativistic jets, and constrain models of jet formation in the inner jet region. We aim to observationally test such inner jet models. The very long baseline interferometry (VLBI) cores of compact radio sources are optically thick at a given frequency. The distance of the core from the central engine is inversely proportional to the frequency. Under the equipartition condition between the magnetic field energy and particle energy densities, the absolute distance of the VLBI core can be predicted. We compiled the brightness temperatures of VLBI cores at various radio frequencies of 2, 8, 15, and 86 GHz. We derive the brightness temperature on sub-parsec scales in the rest frame of the compact radio sources. We find that the brightness temperature increases with increasing distance from the central engine, indicating that the intrinsic jet speed (the Lorentz factor) increases along the jet. This implies that the jets are accelerated in the (sub-)parsec regions from the central engine.

  2. Dynamics of aircraft exhaust plumes in the jet-regime

    Directory of Open Access Journals (Sweden)

    P. Fabian

    Full Text Available A computational model describing the two-dimensional, turbulent mixing of a single jet of exhaust gas from aircraft engines with the ambient atmosphere is presented. The underlying assumptions and governing equations are examined and supplemented by a discussion of analytical solutions. As an application, the jet dynamics of a B747-400 aircraft engine in cruise and its dependence on key parameters is investigated in detail. The computer code for this dynamical model is computationally fast and can easily be coupled to complex chemical and microphysical models in order to perform comprehensive studies of atmospheric effects from aircraft exhaust emissions in the jet regime.

  3. Field Jet Erosion Tests on the Mississippi River Collocated Demonstration Section, Plaquemines Parish, Louisiana

    Science.gov (United States)

    2015-06-01

    ER D C/ G SL T R- 15 -1 3 Field Jet Erosion Tests on the Mississippi River Collocated Demonstration Section, Plaquemines Parish...default. ERDC/GSL TR-15-13 June 2015 Field Jet Erosion Tests on the Mississippi River Collocated Demonstration Section, Plaquemines Parish...Prepared for U.S. Army Corps of Engineers Washington, DC 20314-1000 ERDC/GSL TR-15-13 ii Abstract Field jet erosion tests (JETs) were

  4. Experiment on Conical Pick Cutting Rock Material Assisted with Front and Rear Water Jet

    OpenAIRE

    Xiaohui Liu; Songyong Liu; Lie Li; Xinxia Cui

    2015-01-01

    Conical picks are one kind of cutting tools widely used in engineering machinery. In the process of rock breaking, the conical pick bears great cutting force and wear. To solve the problem, a new method, conical pick assisted with high pressure water jet, could break rock effectively, and four different configuration modes of water jet were presented. In this paper, based on the analysis of the different water jet configuration’s advantages and disadvantages, experiments on front water jet, n...

  5. Jet substructure in ATLAS

    CERN Document Server

    Miller, David W

    2011-01-01

    Measurements are presented of the jet invariant mass and substructure in proton-proton collisions at $\\sqrt{s} = 7$ TeV with the ATLAS detector using an integrated luminosity of 37 pb$^{-1}$. These results exercise the tools for distinguishing the signatures of new boosted massive particles in the hadronic final state. Two "fat" jet algorithms are used, along with the filtering jet grooming technique that was pioneered in ATLAS. New jet substructure observables are compared for the first time to data at the LHC. Finally, a sample of candidate boosted top quark events collected in the 2010 data is analyzed in detail for the jet substructure properties of hadronic "top-jets" in the final state. These measurements demonstrate not only our excellent understanding of QCD in a new energy regime but open the path to using complex jet substructure observables in the search for new physics.

  6. Numerical simulations of dynamics and emission from relativistic astrophysical jets

    CERN Document Server

    Mimica, Petar; Rueda-Becerril, Jesus Misrayim; Tabik, Siham; Aloy, Carmen

    2012-01-01

    Broadband emission from relativistic outflows (jets) of active galactic nuclei (AGN) and gamma-ray bursts (GRBs) contains valuable information about the nature of the jet itself, and about the central engine which launches it. Using special relativistic hydrodynamics and magnetohydronamics simulations we study the dynamics of the jet and its interaction with the surrounding medium. The observational signature of the simulated jets is computed using a radiative transfer code developed specifically for the purpose of computing multi-wavelength, time-dependent, non-thermal emission from astrophysical plasmas. We present results of a series of long-term projects devoted to understanding the dynamics and emission of jets in parsec-scale AGN jets, blazars and the afterglow phase of the GRBs.

  7. Comparison of Vibrations and Emissions of Conventional Jet Fuel with Stressed 100% SPK and Fully Formulated Synthetic Jet Fuel

    Directory of Open Access Journals (Sweden)

    Bhupendra Khandelwal

    2014-08-01

    Full Text Available The rapid growth of the aviation sector around the globe has witnessed an overwhelming impact on fossil fuel resources. With the implementation of stricter environmental laws over emissions by conventional jet fuels, growing demand for research on alternative fuels has become imperative. One-hundred percent Synthetic Paraffinic Kerosene (SPK and Fully Formulated Synthetic Jet Fuel have surfaced as viable alternatives for gas turbine engines due to their similar properties as that of Jet Fuel. This paper presents results from an experimental study performed on a small gas turbine engine, comparing emissions performance and vibrations for conventional Jet A-1 Fuel, thermally stressed 100% SPK and Fully Formulated Synthetic Jet Fuel. Different vibration frequencies, power spectra were observed for different fuels. Gaseous emissions observed were nearly the same, whereas, significant changes in particulates emissions were observed.

  8. 用于清除水面污染物的移动式气动CO2激光器%Jet engine based mobile gas dynamic CO2 laser for water surface cleaning

    Institute of Scientific and Technical Information of China (English)

    APOLLONOV V V

    2012-01-01

    本文介绍的工程项目在于研发一种激光技术来清除大面积海域和其他水面存在的油膜污染物.针对海面严重污染问题,研究了基于喷气发动机的可移动气动CO2激光器(100~250 kW)的设计方案及其在清除水面污染时的工程实现.提出的技术方案意在有效弥补传统的海面油膜处理方法只可处理块状油层而无法消除100 μm厚油膜的弊病.文中介绍了可移动气动CO2激光器的设计机理,研究了可执行该项工作的不同类型的激光器,证明了选用可移动气动CO2激光器执行该项工作的合理性.考虑了激光器系统的供气方案,选择了高质量的喷气发动机作气动CO2激光器的动力设备并设置了该设备工作时需要的容量.最后,描述了该激光系统气动液压设备的设计方案,给出了相关设备、油箱、和操作控制单元的结构.目前,作者已经完成了用于处理水面油膜的气动CO2激光器的概念设计,并制备了相应的激光系统.另外,研制了气动CO2激光器系统的工作平台,通过用激光束扫描石油膜覆盖的水面,实验验证了利用该系统收集油膜和令油膜有效燃烧的可行性.%The purpose of the project presented in the paper is to develop a laser technology to clean large areas of seas and other water surfaces from oil film contamination.It mainly aims development of technological scheme and engineering design of jet engine based mobile Gas Dynamic Lasers (GDLs) (100-250 kW) intended to solve this important problem of environment protection.This method and laser system proposed are expected to complement other traditional methods,which usually more successfully treat bulk layer oil pollution but do not match to eliminate up to 100 μm oil films.In this paper,the basic design concept of a mobile gas dynamic CO2 laser is introduced,and the possibility of using various types of lasers for solution of required tasks is considered and the selection of GDL

  9. Supersonic Injection of Aerated Liquid Jet

    Science.gov (United States)

    Choudhari, Abhijit; Sallam, Khaled

    2016-11-01

    A computational study of the exit flow of an aerated two-dimensional jet from an under-expanded supersonic nozzle is presented. The liquid sheet is operating within the annular flow regime and the study is motivated by the application of supersonic nozzles in air-breathing propulsion systems, e.g. scramjet engines, ramjet engines and afterburners. The simulation was conducted using VOF model and SST k- ω turbulence model. The test conditions included: jet exit of 1 mm and mass flow rate of 1.8 kg/s. The results show that air reaches transonic condition at the injector exit due to the Fanno flow effects in the injector passage. The aerated liquid jet is alternately expanded by Prandtl-Meyer expansion fan and compressed by oblique shock waves due to the difference between the back (chamber) pressure and the flow pressure. The process then repeats itself and shock (Mach) diamonds are formed at downstream of injector exit similar to those typical of exhaust plumes of propulsion system. The present results, however, indicate that the flow field of supersonic aerated liquid jet is different from supersonic gas jets due to the effects of water evaporation from the liquid sheet. The contours of the Mach number, static pressure of both cases are compared to the theory of gas dynamics.

  10. Turbulent buoyant jets and plumes

    CERN Document Server

    Rodi, Wolfgang

    The Science & Applications of Heat and Mass Transfer: Reports, Reviews, & Computer Programs, Volume 6: Turbulent Buoyant Jets and Plumes focuses on the formation, properties, characteristics, and reactions of turbulent jets and plumes. The selection first offers information on the mechanics of turbulent buoyant jets and plumes and turbulent buoyant jets in shallow fluid layers. Discussions focus on submerged buoyant jets into shallow fluid, horizontal surface or interface jets into shallow layers, fundamental considerations, and turbulent buoyant jets (forced plumes). The manuscript then exami

  11. Editorial on Future Jet Technologies

    Science.gov (United States)

    Gal-Or, Benjamin

    2014-12-01

    The jet engine is the prime flight controller in post-stall flight domains where conventional flight control fails, or when the engine prevents catastrophes in training, combat, loss of all airframe hydraulics (the engine retains its own hydraulics), loss of one engine, pilot errors, icing on the wings, landing gear and runway issues in takeoff and landing and in bad-whether recoveries. The scientific term for this revolutionary technology is "jet-steering", and in engineering practice - "thrust vectoring", or "TV". Jet-Steering in advanced fighter aircraft designs is integrated with stealth technology. The resulting classified Thrust-Vectoring-Stealth ("TVS") technology has generated a second jet-revolution by which all Air-&-Sea-Propulsion Science and R&D are now being reassessed. Classified F-22, X-47B/C and RQ-180 TVS-vehicles stand at the front of this revolution. But recent transfers of such sensitive technologies to South Korea and Japan [1-5], have raised various fundamental issues that are evaluated by this editorial-review. One, and perhaps a key conclusion presented here, means that both South Korea and Japan may have missed one of their air-&-sea defenses: To develop and field low-cost unmanned fleets of jet-drones, some for use with expensive, TVS-fighter aircraft in highly congested areas. In turn, the U.S., EU, Russia and China, are currently developing such fleets at various TVS levels and sizes. China, for instance, operates at least 15,000 drones ("UAVs") by 2014 in the civilian sector alone. All Chinese drones have been developed by at least 230 developers/manufacturers [1-16]. Mobile telecommunication of safe links between flyers and combat drones ("UCAVs") at increasingly deep penetrations into remote, congested areas, can gradually be purchased-developed-deployed and then operated by extant cader of tens of thousands "National Champion Flyers" who have already mastered the operation of mini-drones in free-to-all sport clubs under national

  12. Spray formation processes of impinging jet injectors

    Science.gov (United States)

    Anderson, W. E.; Ryan, H. M.; Pal, S.; Santoro, R. J.

    1993-11-01

    A study examining impinging liquid jets has been underway to determine physical mechanisms responsible for combustion instabilities in liquid bi-propellant rocket engines. Primary atomization has been identified as an important process. Measurements of atomization length, wave structure, and drop size and velocity distribution were made under various ambient conditions. Test parameters included geometric effects and flow effects. It was observed that pre-impingement jet conditions, specifically whether they were laminar or turbulent, had the major effect on primary atomization. Comparison of the measurements with results from a two dimensional linear aerodynamic stability model of a thinning, viscous sheet were made. Measured turbulent impinging jet characteristics were contrary to model predictions; the structure of waves generated near the point of jet impingement were dependent primarily on jet diameter and independent of jet velocity. It has been postulated that these impact waves are related to pressure and momentum fluctuations near the impingement region and control the eventual disintegration of the liquid sheet into ligaments. Examination of the temporal characteristics of primary atomization (ligament shedding frequency) strongly suggests that the periodic nature of primary atomization is a key process in combustion instability.

  13. Non-Boussinesq Integral Model for Horizontal Turbulent Buoyant Round Jets

    Directory of Open Access Journals (Sweden)

    J. Xiao

    2009-01-01

    Full Text Available Horizontal buoyant jet is a fundamental flow regime for hydrogen safety analysis in power industry. The purpose of this study is to develop a fast non-Boussinesq engineering model the horizontal buoyant round jets. Verification of this integral model is established with available experimental data and comparisons over a large range of density variations with the CFD codes GASFLOW. The model has proved to be an efficient engineering tool for predicting horizontal strongly buoyant round jets.

  14. Jet Substructure Without Trees

    Energy Technology Data Exchange (ETDEWEB)

    Jankowiak, Martin; Larkoski, Andrew J.; /SLAC /Stanford U., ITP

    2011-08-19

    We present an alternative approach to identifying and characterizing jet substructure. An angular correlation function is introduced that can be used to extract angular and mass scales within a jet without reference to a clustering algorithm. This procedure gives rise to a number of useful jet observables. As an application, we construct a top quark tagging algorithm that is competitive with existing methods. In preparation for the LHC, the past several years have seen extensive work on various aspects of collider searches. With the excellent resolution of the ATLAS and CMS detectors as a catalyst, one area that has undergone significant development is jet substructure physics. The use of jet substructure techniques, which probe the fine-grained details of how energy is distributed in jets, has two broad goals. First, measuring more than just the bulk properties of jets allows for additional probes of QCD. For example, jet substructure measurements can be compared against precision perturbative QCD calculations or used to tune Monte Carlo event generators. Second, jet substructure allows for additional handles in event discrimination. These handles could play an important role at the LHC in discriminating between signal and background events in a wide variety of particle searches. For example, Monte Carlo studies indicate that jet substructure techniques allow for efficient reconstruction of boosted heavy objects such as the W{sup {+-}} and Z{sup 0} gauge bosons, the top quark, and the Higgs boson.

  15. An Air Jet Distortion Generation System

    Directory of Open Access Journals (Sweden)

    M. Sivapragasam

    2014-01-01

    Full Text Available An air jet distortion generation system is developed to simulate the distorted flow field ahead of gas turbine engines in ground test facility. The flow field of a system of four jets arranged circumferentially and issuing into a confined counterflow was studied experimentally and numerically. The total pressure distortion parameters were evaluated at the Aerodynamic Interface Plane (AIP for several values of mass flow ratios. Since the total pressure loss distribution at the AIP is characteristically “V” shaped, the number of jets was increased to obtain total pressure distributions as required for gas turbine engine testing. With this understanding, a methodology has been developed to generate a target total pressure distortion pattern at the AIP. Turbulent flow computations are used to iteratively progress towards the target distribution. This methodology was demonstrated for a distortion flow pattern typical of use in gas turbine engine testing using twenty jets, which is a smaller number than reported in the literature. The procedure converges with a root-mean-square error of 3.836% and is able to reproduce the target pattern and other distortion parameters.

  16. 考虑进排气影响的运输机增升构型气动特性研究%The Research on Aerodynamic Characteristics of High-Lift Configuration of Transport Plane with the Effect of Engine Jet

    Institute of Scientific and Technical Information of China (English)

    张菁; 张晓亮; 江奕廷

    2014-01-01

    以某型运输机增升构型为研究对象,通过数值模拟方法研究了发动机进排气对全机气动特性的影响。计算结果表明:在发动机进排气因素影响下,全机最大升力系数明显增加,失速迎角有较大幅度延迟。通过对流场特性对比分析知:进排气因素不仅对短舱后方襟翼当地流场有较大改善,而且对主翼上表面流场以及平尾当地迎角也有显著影响。基于以上分析认为,在翼吊发动机增升构型设计过程中,进排气因素对各个部件当地流场的影响需要纳入设计考虑范围。%By the method of CFD ( Computational Fluid Dynamic ) , the aerodynamic characteristics of high-lift configuration with the effect of engine jet is researched .The result of numerical simulation demonstrates that with the effect of engine jet , the maximum lift coefficient increases , and the stall angle increases, longitudinal stability factor decreases significantly .Conclusion can be obtained by analyzing the physics characteristics of flow that the engine jet not only changes local flow field of flap after the engine , but also changes the local flow field on the upper surface of nacelle and main wing .In view of the above analysis, during the process of designing high-lift configuration of wing hanging engine , the effects of en-gine jet on the local flow field of each part has to be considered .

  17. Parametric dependencies of JET electron temperature profiles

    Energy Technology Data Exchange (ETDEWEB)

    Schunke, B. [Commission of the European Communities, Abingdon (United Kingdom). JET Joint Undertaking; Imre, K.; Riedel, K. [New York Univ., NY (United States)

    1994-07-01

    The JET Ohmic, L-Mode and H-Mode electron temperature profiles obtained from the LIDAR Thomson Scattering Diagnostic are parameterized in terms of the normalized flux parameter and a set of the engineering parameters like plasma current, toroidal field, line averages electron density... It is shown that the electron temperature profiles fit a log-additive model well. It is intended to use the same model to predict the profile shape for D-T discharges in JET and in ITER. 2 refs., 5 figs.

  18. Transrelativistic pair plasmas in AGN jets

    DEFF Research Database (Denmark)

    Bottcher, M.; Pohl, M.; Schlickeiser, R.

    1999-01-01

    Models of relativistic jets filled with ultrarelativistic pair plasma are very successful in explaining the broadband radiation of gamma-ray blazars. Assuming that the initial injection and cooling of ultrarelativistic pair plasma in an AGN jet has occurred, producing the observed high-energy gamma......-ray radiation, we investigate the further evolution of the pair plasma as it continues to move out from the central engine. The effects of thermalization and reacceleration, the emission of pair bremsstrahlung and annihilation radiation and the bulk Compton process, and the possible application to MeV blazars...

  19. TASI Lectures on Jet Substructure

    CERN Document Server

    Shelton, Jessie

    2013-01-01

    Jet physics is a rich and rapidly evolving field, with many applications to physics in and beyond the Standard Model. These notes, based on lectures delivered at the June 2012 Theoretical Advanced Study Institute, provide an introduction to jets at the Large Hadron Collider. Topics covered include sequential jet algorithms, jet shapes, jet grooming, and boosted Higgs and top tagging.

  20. Jet propagation and deceleration

    CERN Document Server

    Perucho, Manel

    2013-01-01

    Extragalactic jets in active galactic nuclei (AGN) are divided into two morphological types, namely Fanaroff-Riley I (FRI) and Fanaroff-Riley II (FRII). The former show decollimated structure at the kiloparsec scales and are thought to be decelerated by entrainment within the first kiloparsecs of evolution inside the host galaxy. The entrainment and deceleration can be, at least partly, due to the interaction of jets with stellar winds and gas clouds that enter in the jet as they orbit around the galactic centre. In this contribution, I review recent simulations to study the dynamic effect of entrainment from stellar winds in jets and the direct interaction of jets with gas clouds and stellar winds. I also briefly describe the importance of these interactions as a possible scenario of high-energy emission from extragalactic jets.

  1. What ignites optical jets?

    Energy Technology Data Exchange (ETDEWEB)

    Sebastian Jester

    2002-12-23

    The properties of radio galaxies and quasars with and without optical or X-ray jets are compared. The majority of jets from which high-frequency emission has been detected so far (13 with optical emission, 11 with X-rays, 13 with both) are associated with the most powerful radio sources at any given redshift. It is found that optical/X-ray jet sources are more strongly beamed than the average population of extragalactic radio sources. This suggests that the detection or non-detection of optical emission from jets has so far been dominated by surface brightness selection effects, not by jet physics. It implies that optical jets are much more common than is currently appreciated.

  2. Mini-Jet Controlled Turbulent Round Air Jet

    Institute of Scientific and Technical Information of China (English)

    杜诚; 米建春; 周裕; 詹杰

    2011-01-01

    We report an investigation of the active control of a round air jet by multiple radial blowing mini-jets.The Reynolds number based on the jet exit velocity and diameter is 8000.It is found that once the continuous minijets are replaced with pulsed ones,the centerline velocity decay rate K can be greatly increased as the pulsing frequency of mini-jets approaches the natural vortex frequency of the main jet.For example,the K value is amplified by more than 50% with two(or four)pulsed mini-jets blowing,compared with the continuous mini-jets at the same ratio of the mass flow rate of the mini-jets to that of the main jet.%We report an investigation of the active control of a round air jet by multiple radial blowing mini-jets. The Reynolds number based on the jet exit velocity and diameter is 8000. It is found that once the continuous mini-jets are replaced with pulsed ones, the centerline velocity decay rate K can be greatly increased as the pulsing frequency of mini-jets approaches the natural vortex frequency of the main jet. For example, the K value is amplified by more than 50% with two (or four) pulsed mini-jets blowing, compared with the continuous mini-jets at the same ratio of the mass Sow rate of the mini-jets to that of the main jet.

  3. Hotspots, Jets and Environments

    Science.gov (United States)

    Hardcastle, M. J.

    2008-06-01

    I discuss the nature of `hotspots' and `jet knots' in the kpc-scale structures of powerful radio galaxies and their relationship to jet-environment interactions. I describe evidence for interaction between the jets of FRI sources and their local environments, and discuss its relationship to particle acceleration, but the main focus of the paper is the hotspots of FRIIs and on new observational evidence on the nature of the particle acceleration associated with them.

  4. Developing an Empirical Model for Jet-Surface Interaction Noise

    Science.gov (United States)

    Brown, Clifford A.

    2014-01-01

    The process of developing an empirical model for jet-surface interaction noise is described and the resulting model evaluated. Jet-surface interaction noise is generated when the high-speed engine exhaust from modern tightly integrated or conventional high-bypass ratio engine aircraft strikes or flows over the airframe surfaces. An empirical model based on an existing experimental database is developed for use in preliminary design system level studies where computation speed and range of configurations is valued over absolute accuracy to select the most promising (or eliminate the worst) possible designs. The model developed assumes that the jet-surface interaction noise spectra can be separated from the jet mixing noise and described as a parabolic function with three coefficients: peak amplitude, spectral width, and peak frequency. These coefficients are fit to functions of surface length and distance from the jet lipline to form a characteristic spectra which is then adjusted for changes in jet velocity and/or observer angle using scaling laws from published theoretical and experimental work. The resulting model is then evaluated for its ability to reproduce the characteristic spectra and then for reproducing spectra measured at other jet velocities and observer angles; successes and limitations are discussed considering the complexity of the jet-surface interaction noise versus the desire for a model that is simple to implement and quick to execute.

  5. Properties of gluon jets

    Energy Technology Data Exchange (ETDEWEB)

    Sugano, K.

    1986-09-01

    The properties of gluon jets are reviewed from an experimental point of view. The measured characteristics are compared to theoretical expectations. Although neither data nor models for the gluon jets are in the mature stage, there are remarkable agreements and also intriguing disagreements between experiment and theory. Since much interesting data have begun to emerge from various experiments and the properties of gluon jets are deeply rooted in the basic structure of non-Abelian gauge theory, the study of gluon jets casts further light on our understanding of QCD. Finally, the future prospects are discussed.

  6. The hydrogen laminar jet

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez-Sanz, M. [Departamento de Motopropulsion y Termofluidomecanica, ETSI Aeronauticos, Universidad Politecnica de Madrid, 28040 Madrid (Spain); Rosales, M. [Department Ingenieria Termica y de Fluidos, Universidad Carlos III de Madrid, 28911, Leganes (Spain); Instituto de Innovacion en Mineria y Metalurgia, Avenida del Valle 738, Santiago (Chile); Sanchez, A.L. [Department Ingenieria Termica y de Fluidos, Universidad Carlos III de Madrid, 28911, Leganes (Spain)

    2010-04-15

    Numerical and asymptotic methods are used to investigate the structure of the hydrogen jet discharging into a quiescent air atmosphere. The analysis accounts in particular for the variation of the density and transport properties with composition. The Reynolds number of the flow R{sub j}, based on the initial jet radius a, the density {rho}{sub j} and viscosity {mu}{sub j} of the jet and the characteristic jet velocity u{sub j}, is assumed to take moderately large values, so that the jet remains slender and stable, and can be correspondingly described by numerical integration of the continuity, momentum and species conservation equations written in the boundary-layer approximation. The solution for the velocity and composition in the jet development region of planar and round jets, corresponding to streamwise distances of order R{sub j}a, is computed numerically, along with the solutions that emerge both in the near field and in the far field. The small value of the hydrogen-to-air molecular weight ratio is used to simplify the solution by considering the asymptotic limit of vanishing jet density. The development provides at leading-order explicit analytical expressions for the far-field velocity and hydrogen mass fraction that describe accurately the hydrogen jet near the axis. The information provided can be useful in particular to characterize hydrogen discharge processes from holes and cracks. (author)

  7. Jet mass spectra in Higgs+one jet at NNLL

    Energy Technology Data Exchange (ETDEWEB)

    Jouttenus, Teppo T.; Stewart, Iain W. [Massachusetts Institute of Technology, Cambridge, MA (United States). Center for Theoretical Physics; Tackmann, Frank J. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Waalewijn, Wouter J. [California Univ., San Diego, La Jolla, CA (United States). Dept. of Physics

    2013-02-15

    The invariant mass of a jet is a benchmark variable describing the structure of jets at the LHC. We calculate the jet mass spectrum for Higgs plus one jet at the LHC at next-to-next-to-leading logarithmic (NNLL) order using a factorization formula. At this order, the cross section becomes sensitive to perturbation theory at the soft m{sup 2}{sub jet}/p{sup jet}{sub T} scale. Our calculation is exclusive and uses the 1-jettiness global event shape to implement a veto on additional jets. The dominant dependence on the jet veto is removed by normalizing the spectrum, leaving residual dependence from non-global logarithms depending on the ratio of the jet mass and jet veto variables. For our exclusive jet cross section these non-global logarithms are parametrically smaller than in the inclusive case, allowing us to obtain a complete NNLL result. Results for the dependence of the jet mass spectrum on the kinematics, jet algorithm, and jet size R are given. Using individual partonic channels we illustrate the difference between the jet mass spectra for quark and gluon jets. We also study the effect of hadronization and underlying event on the jet mass in Pythia. To highlight the similarity of inclusive and exclusive jet mass spectra, a comparison to LHC data is presented.

  8. Dynamics of Water Jet in Water Jet Looms

    Institute of Scientific and Technical Information of China (English)

    李克让; 陈明

    2001-01-01

    On the base of the study on dynamics of water jet in water jet looms, the parameters of water jet mechanism which affect the speed of water jet are analyzed and optimized. So the stability of the water jet can be improved to raise the speed of water jet as well as weft insertion rate and to enlarge the width of woven fabrics a lot. At the same time it also points out that to increase water jet speed and to prolong its affective jet time depend mainly on the accretion of spring rate (constant)of stiffness and the diminution of plunger's cross sectional area respectively.

  9. Dilution jet experiments in compact combustor configurations

    Science.gov (United States)

    Greber, I.; Zizelman, J.

    1984-01-01

    This project concerns the effects of cooling jets on the velocity and temperature fields in a compact reverse flow combustor. The work is motivated by the need to limit the temperatures of post combustion gases in jet engines to values within the endurance capabilities of turbine blades. The application requires not only that the temperature be kept sufficiently low but also that a suitably tailored temperature profile be provided at the combustor exit, with higher temperatures generally permissible at the blade tip than at the blade root because of higher centrifugal loads at the root. Flows in reverse flow combustor accelerate both longitudinally because of area changes and transversely because of flow turning. The current project started with flow visualization experiments in water, using aqueous solutions of zinc bromide to model the relatively higher density of cooling jets.

  10. Faraday, Jets, and Sand

    NARCIS (Netherlands)

    Sandtke, M.; van der Meer, Roger M.; Versluis, Andreas Michel; Lohse, Detlef

    2003-01-01

    When a 6-mm layer of fine sand with an average grain size of 40 µm is poured into a cylindrical container and shaken vertically, thin jets are seen to emerge from an airy cloud of grains, almost like protuberances from the corona of the sun. A quasi two-dimensional setup reveals the jet-formation

  11. Volcanic jet noise: infrasonic source processes and atmospheric propagation

    Science.gov (United States)

    Matoza, R. S.; Fee, D.; Ogden, D. E.

    2011-12-01

    Volcanic eruption columns are complex flows consisting of (possibly supersonic) injections of ash-gas mixtures into the atmosphere. A volcanic eruption column can be modeled as a lower momentum-driven jet (the gas-thrust region), which transitions with altitude into a thermally buoyant plume. Matoza et al. [2009] proposed that broadband infrasonic signals recorded during this type of volcanic activity represent a low-frequency form of jet noise. Jet noise is produced at higher acoustic frequencies by smaller-scale man-made jet flows (e.g., turbulent jet flow from jet engines and rockets). Jet noise generation processes could operate at larger spatial scales and produce infrasonic frequencies in the lower gas-thrust portion of the eruption column. Jet-noise-like infrasonic signals have been observed at ranges of tens to thousands of kilometers from sustained volcanic explosions at Mount St. Helens, WA; Tungurahua, Ecuador; Redoubt, AK; and Sarychev Peak, Kuril Islands. Over such distances, the atmosphere cannot be considered homogeneous. Long-range infrasound propagation takes place primarily in waveguides formed by vertical gradients in temperature and horizontal winds, and exhibits strong spatiotemporal variability. The timing and location of volcanic explosions can be estimated from remote infrasonic data and could be used with ash cloud dispersion forecasts for hazard mitigation. Source studies of infrasonic volcanic jet noise, coupled with infrasound propagation modeling, hold promise for being able to constrain more detailed eruption jet parameters with remote, ground-based geophysical data. Here we present recent work on the generation and propagation of volcanic jet noise. Matoza, R. S., D. Fee, M. A. Garcés, J. M. Seiner, P. A. Ramón, and M. A. H. Hedlin (2009), Infrasonic jet noise from volcanic eruptions, Geophys. Res. Lett., 36, L08303, doi:10.1029/2008GL036486.

  12. Jet propulsion without inertia

    CERN Document Server

    Spagnolie, Saverio E

    2010-01-01

    A body immersed in a highly viscous fluid can locomote by drawing in and expelling fluid through pores at its surface. We consider this mechanism of jet propulsion without inertia in the case of spheroidal bodies, and derive both the swimming velocity and the hydrodynamic efficiency. Elementary examples are presented, and exact axisymmetric solutions for spherical, prolate spheroidal, and oblate spheroidal body shapes are provided. In each case, entirely and partially porous (i.e. jetting) surfaces are considered, and the optimal jetting flow profiles at the surface for maximizing the hydrodynamic efficiency are determined computationally. The maximal efficiency which may be achieved by a sphere using such jet propulsion is 12.5%, a significant improvement upon traditional flagella-based means of locomotion at zero Reynolds number. Unlike other swimming mechanisms which rely on the presentation of a small cross section in the direction of motion, the efficiency of a jetting body at low Reynolds number increas...

  13. Performance of direct injection methanol engine using the fuel jet impingement and diffusion. ; Comparison between the spark plug and glow plug ignitions. Nenryo funryu no shototsu kakusan wo riyoshita chokufun methanol kikan no seino. ; Spark plug oyobi glow plug chakka hoshiki no hikaku

    Energy Technology Data Exchange (ETDEWEB)

    Kato, S.; Onishi, S.

    1993-01-20

    The purpose of this paper is to compare the performance of direct fuel injection methanol engines with the spark plug and glow plug ignition systems. These methanol engines utilize the formation of fuel-air mixture by the fuel jet impingement and diffusion. Engine performance and cylinder pressure for the both ignition systems were analyzed. Piezoelectric pressure indicator was used for the cylinder pressure measurements, and combustion analyzer was used for their analyses. In order to estimate engine performance, effects of load and engine speed were analyzed. Consequently, almost the same brake thermal efficiencies (maximum value of 42%) were obtained for both ignition systems. For the glow plug ignition system, the combustion noise and NOx emission were lower than the spark plug engine. The NOx emission did not excess 500ppm with the glow plug ignition system. In the impingement and diffusion method, both the piston attached type impingement part and cylinder head fixed type one were applicable. 4 refs., 9 figs., 2 tabs.

  14. Magnetic Field Structure in Relativistic Jets

    Directory of Open Access Journals (Sweden)

    Jermak Helen

    2013-12-01

    Full Text Available Relativistic jets are ubiquitous when considering an accreting black hole. Two of the most extreme examples of these systems are blazars and gamma-ray bursts (GRBs, the jets of which are thought to be threaded with a magnetic field of unknown structure. The systems are made up of a black hole accreting matter and producing, as a result, relativistic jets of plasma from the poles of the black hole. Both systems are viewed as point sources from Earth, making it impossible to spatially resolve the jet. In order to explore the structure of the magnetic field within the jet we take polarisation measurements with the RINGO polarimeters on the world’s largest fully autonomous, robotic optical telescope: The Liverpool Telescope. Using the polarisation degree and angle measured by the RINGO polarimeters it is possible to distinguish between global magnetic fields created in the central engine and random tangled magnetic fields produced locally in shocks. We also monitor blazar sources regularly during quiescence with periods of flaring monitored more intensively. Reported here are the early polarisation results for GRBs 060418 and 090102, along with future prospects for the Liverpool Telescope and the RINGO polarimeters.

  15. Collapsar Jets, Bubbles and Fe Lines

    CERN Document Server

    Mészáros, P

    2001-01-01

    According to collapsar models, gamma ray bursts are caused by relativistic jets that expel energy along the rotation axis of a collapsing stellar core. We discuss how the structure and time-dependence of such jets depends on the properties of the stellar envelope and the central engine. It takes a few seconds for the jet to bore its way through the core of the star; most of the energy output during that period goes into a cocoon of relativistic plasma surrounding the jet. This material subsequently forms a bubble of highly-magnetised plasma that would take several hours to expand, subrelativistically, through the extended envelope of a high-mass supergiant. Shock waves and magnetic dissipation in this plasma (where the internal fields could still be $10^5$ G) can contribute a non thermal UV/X-ray afterglow, and also excite Fe line emission from thermal gas, in addition to the standard power-law afterglow from the jet deceleration shock.

  16. LIF Measurement of Interacting Gas Jet Flow with Plane Wall

    Science.gov (United States)

    Yanagi, A.; Kurihara, S.; Yamazaki, S.; Ota, M.; Maeno, K.

    2011-05-01

    Discharging rarefied gas jets in low-pressure conditions are interesting and important phenomena from an engineering point of view. For example they relate to the attitude control of the space satellite, or the semiconductor technology. The jets, however, deform to the complicated shapes by interacting with solid walls. In this paper we have performed the experiments the flow visualization as a first step by applying the LIF (Laser Induced Fluorescence) method on the jet-wall interaction. Jet is spouting out from a φ1.0 mm circular hole into the low pressure air chamber, impinging on a flat plate. The LIF visualization of interacting rarefied gas jet is carried out by using the iodine (I2) tracer and argon ion laser.

  17. Magnetic Resonance Velocimetry analysis of an angled impinging jet

    Science.gov (United States)

    Irhoud, Alexandre; Benson, Michael; Verhulst, Claire; van Poppel, Bret; Elkins, Chris; Helmer, David

    2016-11-01

    Impinging jets are used to achieve high heat transfer rates in applications ranging from gas turbine engines to electronics. Despite the importance and relative simplicity of the geometry, simulations historically fail to accurately predict the flow behavior in the vicinity of the flow impingement. In this work, we present results from a novel experimental technique, Magnetic Resonance Velocimetry (MRV), which measures three-dimensional time-averaged velocity without the need for optical access. The geometry considered in this study is a circular jet angled at 45 degrees and impinging on a flat plate, with a separation of approximately seven jet diameters between the jet exit and the impingement location. Two flow conditions are considered, with Reynolds numbers of roughly 800 and 14,000. Measurements from the MRV experiment are compared to predictions from Reynolds Averaged Navier Stokes (RANS) simulations, thus demonstrating the utility of MRV for validation of numerical analyses of impinging jet flow.

  18. Supersonic Jet Noise: Main Sources and Reduction Methodologies

    Directory of Open Access Journals (Sweden)

    Mohammadreza Azimi

    2014-07-01

    Full Text Available The large velocity ratio and the presence of Shocks in the exhaust plume from low bypass engines or supersonic jetliners cause jet noise to be dominant component of overall aircraft noise, and therefore is an important issue in design of the next generation of civil supersonic transport. Jet noise reduction technology also has application in the design of highperformance tactical aircraft. Jet noise is of particular concern on aircraft carriers where it is necessary for deck crew to be in relatively close proximity to the aircraft at takeoff and landing. In this paper, a brief discussion about supersonic jet noise sources and a review of the main passive technologies employed for the reduction of supersonic jet noise are presented.

  19. NUMERICAL SIMULATION OF 3-D AERATED JET BEHIND FLIP BUCKET OF OVERFLOW DAM

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Aerated jet,such as the jet flow behind the flip bucket of an overflow dam, widely exists in hydraulic engineering. Up to now the model test and prototype observation have been two main methods of studying the aerated jet for a special hydraulic project. In this paper, a three-dimensional mathematical model for the aerated jet was established. It seems that the suggested model has high predictive power by comparison with the results of model tests and prototype observations, which is very useful in the study of energy dissipation and jet flow atomization.

  20. Simulations of Solar Jets

    Science.gov (United States)

    Kohler, Susanna

    2017-02-01

    Formation of a coronal jet from twisted field lines that have reconnected with the ambient field. The colors show the radial velocity of the plasma. [Adapted from Szente et al. 2017]How do jets emitted from the Suns surface contribute to its corona and to the solar wind? In a recent study, a team of scientists performed complex three-dimensional simulations of coronal jets to answer these questions.Small ExplosionsCoronal jets are relatively small eruptions from the Suns surface, with heights of roughly 100 to 10,000 km, speeds of 10 to 1,000 km/s, and lifetimes of a few minutes to around ten hours. These jets are constantly present theyre emitted even from the quiet Sun, when activity is otherwise low and weve observed them with a fleet of Sun-watching space telescopes spanning the visible, extreme ultraviolet (EUV), and X-ray wavelength bands.A comparison of simulated observations based on the authors model (left panels) to actual EUV and X-ray observations of jets (right panels). [Szente et al. 2017]Due to their ubiquity, we speculate that these jets might contribute to heating the global solar corona (which is significantly hotter than the surface below it, a curiosity known as the coronal heating problem). We can also wonder what role these jets might play in driving the overall solar wind.Launching a JetLed by Judit Szente (University of Michigan), a team of scientists has explored the impact of coronal jets on the global corona and solar wind with a series of numerical simulations. Szente and collaborators used three-dimensional, magnetohydrodynamic simulations that provide realistic treatment of the solar atmosphere, the solar wind acceleration, and the complexities of heat transfer throughout the corona.In the authors simulations, a jet is initiated as a magnetic dipole rotates at the solar surface, winding up field lines. Magnetic reconnection between the twisted lines and the background field then launches the jet from the dense and hot solar

  1. Probing the inner jet of M87; from the jet base to HST-1

    Directory of Open Access Journals (Sweden)

    Hada Kazuhiro

    2013-12-01

    Full Text Available The giant radio galaxy M87 accompanies one of the nearest Active-Galactic-Nuclei jets showing the intense radiation through radio to TeV gamma-ray. Its proximity and the large mass of the central black hole provide an excellent advantage to probe the sites of jet formation and gamma-ray production. Here we review some of our recent studies for the inner jet of M87 based on the multi-frequency and multi-epoch VLBI observations, especially focusing on the two remarkable regions i.e., the jet base near the black hole and the peculiar feature HST-1. Our multi-frequency observations with the phase-referencing technique revealed the detailed structure of the jet base region regarding the location of the central engine and the collimation profile. In terms of HST-1, the intense multi-epoch VLBI monitoring constrained the accurate kinematic properties and the structural variations in this complicated feature, together with a possible connection to the gamma-ray activities. At the end of this contribution, we briefly describe our new monitoring project for M87 with VERA, which permits a detailed study on the structural evolution in the jet base region.

  2. Sulfur Speciation and Extraction in Jet A (Briefing Charts)

    Science.gov (United States)

    2015-08-16

    present in Jet A: • Detrimental to engine performance: coking, clogging, fouling, and deposits possible • SOx emissions are an...Charts 3. DATES COVERED (From - To) July 2015-August 2015 4. TITLE AND SUBTITLE Sulfur Speciation and Extraction in Jet A (Briefing Charts) 5a...T. Reams, Richard C. Lee, Joseph M. Mabry 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER Q0BG 7. PERFORMING ORGANIZATION NAME(S

  3. Jets and QCD

    Energy Technology Data Exchange (ETDEWEB)

    Ali, A. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Kramer, G. [Hamburg Univ. (Germany). II. Inst. fuer Theoretische Physik

    2010-12-15

    The observation of quark and gluon jets has played a crucial role in establishing Quantum Chromodynamics [QCD] as the theory of the strong interactions within the Standard Model of particle physics. The jets, narrowly collimated bundles of hadrons, reflect configurations of quarks and gluons at short distances. Thus, by analysing energy and angular distributions of the jets experimentally, the properties of the basic constituents of matter and the strong forces acting between them can be explored. In this review we summarise the properties of quark and gluon jets and the impact of their observation on Quantum Chromodynamics, primarily the discovery of the gluons as the carriers of the strong force. Focusing on these basic points, jets in e{sup +}e{sup -} collisions will be in the foreground of the discussion. In addition we will delineate the role of jets as tools for exploring other particle aspects in ep and pp/p anti p collisions - quark and gluon densities in protons, measurements of the QCD coupling, fundamental 2-2 quark/gluon scattering processes, but also the impact of jet decays of top quarks, and W{sup {+-}},Z bosons on the electroweak sector. The presentation to a large extent is formulated in a non-technical language with the intent to recall the significant steps historically and convey the significance of this field also to communities beyond high energy physics. (orig.)

  4. Solar coronal jets

    Science.gov (United States)

    Dobrzyck, D.

    The solar jets were first observed by SOHO instruments (EIT, LASCO, UVCS) during the previous solar minimum. They were small, fast ejections originating from flaring UV bright points within large polar coronal holes. The obtained data provided us with estimates of the jet plasma conditions, dynamics, evolution of the electron temperature and heating rate required to reproduce the observed ionization state. To follow the polar jets through the solar cycle a special SOHO Joint Observing Program (JOP 155) was designed. It involves a number of SOHO instruments (EIT, CDS, UVCS, LASCO) as well as TRACE. The coordinated observations have been carried out since April 2002. The data enabled to identify counterparts of the 1996-1998 solar minimum jets. Their frequency of several events per day appear comparable to the frequency from the previous solar minimum. The jets are believed to be triggered by field line reconnection between emerging magnetic dipole and pre-existing unipolar field. Existing models predict that the hot jet is formed together with another jet of a cool material. The particular goal of the coordinated SOHO and TRACE observations was to look for possible association of the hot and cool plasma ejections. Currently there is observational evidence that supports these models.

  5. Jet Penetration into a Scaled Microfabricated Stirling Cycle Regenerator

    Science.gov (United States)

    Sun, Liyong; Simon, Terrence W.; Mantell, Susan; Ibrahim, Mournir; Gedeon, David; Tew, Roy

    2008-01-01

    The cooler and heater adjacent to the regenerator of a Stirling cycle engine have tubes or channels which form jets that pass into the regenerator while diffusing within the matrix. An inactive part of the matrix, beyond the cores of these jets, does not participate fully in the heat transfer between the flow of working fluid and the regenerator matrix material, weakening the regenerator s ability to exchange heat with the working fluid. The objective of the present program is to document this effect on the performance of the regenerator and to develop a model for generalizing the results. However, the small scales of actual Stirling regenerator matrices (on the order of tens of microns) make direct measurements of this effect very difficult. As a result, jet spreading within a regenerator matrix has not been characterized well and is poorly understood. Also, modeling is lacking experimental verification. To address this, a large-scale mockup of thirty times actual scale was constructed and operated under conditions that are dynamically similar to the engine operation. Jet penetration with round jets and slot jets into the microfabricated regenerator geometry are then measured by conventional means. The results are compared with those from a study of spreading of round jets within woven screen regenerator for further documentation of the comparative performance of the microfabricated regenerator geometry.

  6. Acoustics of dual-stream high-speed jets

    Science.gov (United States)

    Debiasi, Marco Tullio

    2000-10-01

    This work presents the results of noise measurements in high-speed, round jets whose Mach number and velocity simulate the conditions of jet engines at take-off. The Mach number of the jet potential core ranged from 1.27 to 1.77 and the velocity ranged from 550 m/s to 1010 m/s. Most of the jets were silenced with a coflow that prevented the formation of Mach waves, a dominant contribution to supersonic jet noise. This method, called Mach Wave Elimination, relies on the shielding effect of the coflow which makes the motion of the eddies subsonic with respect to the surrounding streams, thus impeding the creation of Mach waves. Schlieren photography and pitot probe surveys were used to detect the principal features and the growth rate of the jets. Microphone measurements were performed inside an anechoic chamber at many positions around the jet exit. The results were corrected for the microphone response and for the effect of human sensitivity to sound. Equal-thrust comparison of different experimental results shows that elimination of Mach waves is very effective in reducing noise in the direction of strongest emission. Except for localized shock-associated components, noise emission was found to be insensitive to nozzle exit pressure and to depend principally on the values of fully-expanded Mach number and velocity in the jet potential core. Jets with a shorter Mach wave emitting region exhibited better noise suppression. Best results were obtained with an eccentric coflow that allows the shear layer of the upper part of the jet to grow naturally while silencing the jet in the downward direction. Coflows are capable of reducing the near-field screech peaks by up to 10 dB in imperfectly-expanded jets. Scaling the experimental results to a fall-size engine shows that eccentric coflows reduce the noise perceived in the direction of peak emission by up to 11 dB. Preliminary analysis of the application of this silencing technique to engine design indicates that Mach

  7. On the Scaling of Small, Heat Simulated Jet Noise Measurements to Moderate Size Exhaust Jets

    Science.gov (United States)

    McLaughlin, Dennis K.; Bridges, James; Kuo, Ching-Wen

    2010-01-01

    Modern military aircraft jet engines are designed with variable geometry nozzles to provide optimum thrust in different operating conditions, depending on the flight envelope. However, the acoustic measurements for such nozzles are scarce, due to the cost involved in making full scale measurements and the lack of details about the exact geometry of these nozzles. Thus the present effort at The Pennsylvania State University and the NASA Glenn Research Center- in partnership with GE Aviation is aiming to study and characterize the acoustic field produced by supersonic jets issuing from converging-diverging military style nozzles. An equally important objective is to validate methodology for using data obtained from small and moderate scale experiments to reliably predict the most important components of full scale engine noise. The experimental results presented show reasonable agreement between small scale and moderate scale jet acoustic data, as well as between heated jets and heat-simulated ones. Unresolved issues however are identified that are currently receiving our attention, in particular the effect of the small bypass ratio airflow. Future activities will identify and test promising noise reduction techniques in an effort to predict how well such concepts will work with full scale engines in flight conditions.

  8. Jets with Variable R

    CERN Document Server

    Krohn, David; Wang, Lian-Tao

    2009-01-01

    We introduce a new class of jet algorithms designed to return conical jets with a variable Delta R radius. A specific example, in which Delta R scales as 1/pT, proves particularly useful in capturing the kinematic features of a wide variety of hard scattering processes. We implement this Delta R scaling in a sequential recombination algorithm and test it by reconstructing resonance masses and kinematic endpoints. These test cases show 10-20% improvements in signal efficiency compared to fixed Delta R algorithms. We also comment on cuts useful in reducing continuum jet backgrounds.

  9. The research of aerodynamic characteristics of high-lift configuration of large transport plane with the effect of engine jet%考虑动力影响的大型运输机增升构型气动特性研究

    Institute of Scientific and Technical Information of China (English)

    白俊强; 张晓亮; 刘南; 董建鸿; 董强; 周林

    2014-01-01

    为满足现代大型运输机增升系统高效、稳定的设计需求,以某型运输机增升构型为研究对象,通过数值模拟方法研究了动力因素对全机气动特性的影响。数值模拟结果表明:在动力因素影响下,全机最大升力系数增加46.2%,失速迎角增加11°;全机静安定度降低30.89%。通过流场机理分析可知:动力因素不仅对短舱后方襟翼当地流场有较大改善,而且对短舱和主翼上表面流场以及平尾当地迎角也有显著影响。基于以上结论,在运输机增升构型设计过程中,要充分考虑动力因素对各个部件当地流场的影响以提高升力特性;同时要权衡动力因素使机翼低头力矩增加、平尾低头力矩降低这两种趋势相反的影响结果以改善俯仰力矩特性。%To satisfy the design request of efficiency and stability of high-lift system of large transport plane,by the method of CFD (Computational Fluid Dynamic),the research of aerodynamic characteristics of high-lift configuration of large transport plane with the effect of engine jet has been done.The result of nu-merical simulation demonstrates that with the effect of engine jet,the maximum lift coefficient increases by 46.2%,and the stall angle increases by 11 degrees,longitudinal stability factor decreases by 30.89%.Con-clusion can be obtained by analyzing the physics characteristics of flow that the engine jet not only changes local flow fluid of flap after the engine but also changes the local flow fluid on the upper surface of nacelle and main wing and the local angle of attack of horizontal tail.Given the conclusion obtained above,during the procession of designing high-lift configuration of STOL transport airplane,for the lift characteristics the effect of engine jet on the local flow fluid of each part has to be considered;for the pitch moment characteris-tics the reverse effect of engine jet increasing nose-down pitching moment of

  10. Modelling and numerical simulation of two-phase flow processes and combustion processes in a ram-jet engine with boron as a solid fuel; Modellierung und numerische Simulation der zweiphasigen Stroemungs- und Verbrennungsvorgaenge in einem Staustrahltriebwerk mit Bor als Festtreibstoff

    Energy Technology Data Exchange (ETDEWEB)

    Hussmann, Bjoern

    2009-07-01

    The contribution under consideration contacts engineers and scientists within the range of numeric simulation of dense multiphase flows and in the area of the particle combustion. The first part of the contribution describes the flows arising in ram-jet engines with solid propellant such as particle-particle collisions and transsonic nozzle flows with a high load. The second part of the contribution is dedicated to the combustion processes at high-energy boron particles as fuel additive. The second part also gives a comprehensive review of the literature to this topic and compares the existing models. One of these models is extended by a more exact consideration of kinetics as well as diffusion processes at the particle and validated on the basis of experimental data from the literature. Finally, the author reports on the chemistry-turbulence coupling of particles combusting in turbulent flows.

  11. Measurements of Jets in ALICE

    CERN Document Server

    Nattrass, Christine

    2016-01-01

    The ALICE detector can be used for measurements of jets in pp , p Pb, and Pb–Pb collisions. Measurements of jets in pp collisions are consis- tent with expectations from perturbative calculations and jets in p Pb scale with the number of nucleon–nucleon collisions, indicating that cold nuclear matter effects are not observed for jets. Measurements in Pb–Pb collisions demonstrate suppression of jets relative to expectations from binary scaling to the equivalent number of nucleon–nucleon collisions

  12. Jet lag prevention

    Science.gov (United States)

    ... medlineplus.gov/ency/patientinstructions/000719.htm Jet lag prevention To use the sharing features on this page, ... Headache Irritability Stomach upset Sore muscles Tips for Prevention Before your trip: Get plenty of rest, eat ...

  13. Study on diesel cylinder-head cooling using nanofluid coolant with jet impingement

    Directory of Open Access Journals (Sweden)

    Su Zhong-Gen

    2015-01-01

    Full Text Available To improve the heat-transfer performance of a diesel-engine cylinder head, nanofluid coolant as a new fluid was investigated, and jet impingement technology was then used to study on how to better improve heat-transfer coefficient at the nose bridge area in the diesel-engine cylinder head. Computational fluid dynamic simulation and experiments results demonstrated that using the same jet impingement parameters, the different volume shares of nanofluids showed better cooling effect than traditional coolant, but the good effect of the new cooling method was unsuitable for high volume share of nanofluid. At the same volume share of nanofluid, different jet impingement parameters such as jet angles showed different heat-transfer performance. This result implies that a strong association exists between jet impingement parameters and heat-transfer coefficient. The increase in coolant viscosity of the nanofluid coolant using jet impingement requires the expense of more drive-power cost.

  14. Jets and QCD

    CERN Document Server

    Ali, Ahmed

    2010-01-01

    The observation of quark and gluon jets has played a crucial role in establishing Quantum Chromodynamics [QCD] as the theory of the strong interactions within the Standard Model of particle physics. The jets, narrowly collimated bundles of hadrons, reflect configurations of quarks and gluons at short distances. Thus, by analysing energy and angular distributions of the jets experimentally, the properties of the basic constituents of matter and the strong forces acting between them can be explored. In this review we summarise the properties of quark and gluon jets and the impact of their observation on Quantum Chromodynamics, primarily the discovery of the gluons as the carriers of the strong force. Focusing on these basic points, jets in $e^+ e^-$ collisions will be in the foreground of the discussion. In addition we will delineate the role of jets as tools for exploring other particle aspects in $ep$ and $pp/p\\bar{p}$ collisions - quark and gluon densities in protons, measurements of the QCD coupling, fundam...

  15. Jet Mass Spectra in Higgs + One Jet at NNLL

    CERN Document Server

    Jouttenus, Teppo T; Tackmann, Frank J; Waalewijn, Wouter J

    2013-01-01

    The invariant mass of a jet is a benchmark variable describing the structure of jets at the LHC. We calculate the jet mass spectrum for Higgs plus one jet at the LHC at next-to-next-to-leading logarithmic (NNLL) order using a factorization formula. At this order, the cross section becomes sensitive to perturbation theory at the soft m_jet^2/p_T^jet scale. Our calculation is exclusive and uses the 1-jettiness global event shape to implement a veto on additional jets. The dominant dependence on the jet veto is removed by normalizing the spectrum, leaving residual dependence from non-global logarithms depending on the ratio of the jet mass and jet veto variables. For our exclusive jet cross section these non-global logarithms are parametrically smaller than in the inclusive case, allowing us to obtain a complete NNLL result. Results for the dependence of the jet mass spectrum on the kinematics, jet algorithm, and jet size R are given. Using individual partonic channels we illustrate the difference between the je...

  16. UNIFYING THE ZOO OF JET-DRIVEN STELLAR EXPLOSIONS

    Energy Technology Data Exchange (ETDEWEB)

    Lazzati, Davide; Blackwell, Christopher H. [Department of Physics, NC State University, 2401 Stinson Drive, Raleigh, NC 27695-8202 (United States); Morsony, Brian J. [Department of Astronomy, University of Wisconsin-Madison, 2535 Sterling Hall, 475 N. Charter Street, Madison WI 53706-1582 (United States); Begelman, Mitchell C. [JILA, University of Colorado, 440 UCB, Boulder, CO 80309-0440 (United States)

    2012-05-01

    We present a set of numerical simulations of stellar explosions induced by relativistic jets emanating from a central engine sitting at the center of compact, dying stars. We explore a wide range of durations of the central engine activity, two candidate stellar progenitors, and two possible values of the total energy release. We find that even if the jets are narrowly collimated, their interaction with the star unbinds the stellar material, producing a stellar explosion. We also find that the outcome of the explosion can be very different depending on the duration of the engine activity. Only the longest-lasting engines result in successful gamma-ray bursts. Engines that power jets only for a short time result in relativistic supernova (SN) explosions, akin to observed engine-driven SNe such as SN2009bb. Engines with intermediate durations produce weak gamma-ray bursts, with properties similar to nearby bursts such as GRB 980425. Finally, we find that the engines with the shortest durations, if they exist in nature, produce stellar explosions that lack sizable amounts of relativistic ejecta and are therefore dynamically indistinguishable from ordinary core-collapse SNe.

  17. Technical Possibilities of Noise Reduction in Material Cutting by Abrasive Water-jet

    OpenAIRE

    Radvanská, Agáta; Ergić, Todor; IVANDIĆ, Željko; Hloch, Sergej; Valiček, Jan; Mullerova, Jana

    2009-01-01

    The technical procedure of noise reduction in material cutting by abrasive water-jet is described in this paper. The paper is aimed at the implementation of technical possibilities of noise reduction in the cutting of material by abrasive water-jet technology. Both the theoretical and experimental investigations were performed to verify and specify the new findings in the reduction of acoustic sound pressure at abrasive water-jet machining of engineering materials. By means of identification,...

  18. Experimental study of a vertical jet in a vegetated crossflow.

    Science.gov (United States)

    Ben Meftah, Mouldi; De Serio, Francesca; Malcangio, Daniela; Mossa, Michele; Petrillo, Antonio Felice

    2015-12-01

    Aquatic ecosystems have long been used as receiving environments of wastewater discharges. Effluent discharge in a receiving water body via single jet or multiport diffuser, reflects a number of complex phenomena, affecting the ecosystem services. Discharge systems need to be designed to minimize environmental impacts. Therefore, a good knowledge of the interaction between effluents, discharge systems and receiving environments is required to promote best environmental management practice. This paper reports innovative 3D flow velocity measurements of a jet discharged into an obstructed crossflow, simulating natural vegetated channel flows for which correct environmental management still lacks in literature. In recent years, numerous experimental and numerical studies have been conducted on vegetated channels, on the one hand, and on turbulent jets discharged into unvegetated crossflows, on the other hand. Despite these studies, however, there is a lack of information regarding jets discharged into vegetated crossflow. The present study aims at obtaining a more thorough understanding of the interaction between a turbulent jet and an obstructed crossflow. In order to achieve such an objective, a series of laboratory experiments was carried out in the Department of Civil, Environmental, Building Engineering and Chemistry of the Technical University of Bari - Italy. The physical model consists of a vertical jet discharged into a crossflow, obstructed by an array of vertical, rigid, circular and threaded steel cylinders. Analysis of the measured flow velocities shows that the array of emergent rigid vegetation significantly affects the jet and the ambient flow structures. It reduces the mean channel velocity, allowing the jet to penetrate higher into the crossflow. It significantly increases the transversal flow motion, promoting a major lateral spreading of the jet within the crossflow. Due to the vegetation array effects, the jet undergoes notable variations in its

  19. GRMHD Simulations of Disk/Jet Systems: Application to Collapsars

    CERN Document Server

    De Villiers, J P; Ouyed, R; Villiers, Jean-Pierre De; Staff, Jan; Ouyed, Rachid

    2005-01-01

    We have carried out 2D and 3D general relativistic magnetohydrodynamic simulations of jets launched self-consistently from accretion disks orbiting Kerr black holes. The accretion flow generates energetic jets in the axial funnel region of the disk/jet system, as well as a substantial coronal wind. The jets feature knot-like structures of extremely hot, ultra-relativistic gas; the gas in these knots begins at moderate velocities near the central engine, and is accelerated to ultra-relativistic velocities (Lorentz factors of 50, and higher) by the action of the magnetic field in the axial funnel. The increase in jet velocity takes place in an acceleration zone extending to at least a few hundred gravitational radii from the central engine. The overall energetics of the jets are strongly spin-dependent, with high-spin black holes producing the highest energy and mass fluxes. In addition, with high-spin black holes, the ultra-relativistic outflow is cylindrically collimated within a few hundred gravitational rad...

  20. B-jets and z + b-jets at CDF

    Energy Technology Data Exchange (ETDEWEB)

    Jeans, Daniel; /Rome U.

    2006-06-01

    The authors present CDF cross-section measurements for the inclusive production of b jets and the production of b jets in association with a Z{sup 0} boson. Both measurements are in reasonable agreement with NLO QCD predictions.

  1. Establishing Consensus Turbulence Statistics for Hot Subsonic Jets

    Science.gov (United States)

    Bridges, James; Werner, Mark P.

    2010-01-01

    Many tasks in fluids engineering require knowledge of the turbulence in jets. There is a strong, although fragmented, literature base for low order statistics, such as jet spread and other meanvelocity field characteristics. Some sources, particularly for low speed cold jets, also provide turbulence intensities that are required for validating Reynolds-averaged Navier-Stokes (RANS) Computational Fluid Dynamics (CFD) codes. There are far fewer sources for jet spectra and for space-time correlations of turbulent velocity required for aeroacoustics applications, although there have been many singular publications with various unique statistics, such as Proper Orthogonal Decomposition, designed to uncover an underlying low-order dynamical description of turbulent jet flow. As the complexity of the statistic increases, the number of flows for which the data has been categorized and assembled decreases, making it difficult to systematically validate prediction codes that require high-level statistics over a broad range of jet flow conditions. For several years, researchers at NASA have worked on developing and validating jet noise prediction codes. One such class of codes, loosely called CFD-based or statistical methods, uses RANS CFD to predict jet mean and turbulent intensities in velocity and temperature. These flow quantities serve as the input to the acoustic source models and flow-sound interaction calculations that yield predictions of far-field jet noise. To develop this capability, a catalog of turbulent jet flows has been created with statistics ranging from mean velocity to space-time correlations of Reynolds stresses. The present document aims to document this catalog and to assess the accuracies of the data, e.g. establish uncertainties for the data. This paper covers the following five tasks: Document acquisition and processing procedures used to create the particle image velocimetry (PIV) datasets. Compare PIV data with hotwire and laser Doppler

  2. Combined Thermo-Hydraulic Analysis of a Cryogenic Jet

    CERN Document Server

    Chorowski, M

    1999-01-01

    A cryogenic jet is a phenomenon encountered in different fields like some technological processes and cryosurgery. It may also be a result of cryogenic equipment rupture or a cryogen discharge from the cryostats following resistive transition in superconducting magnets. Heat exchange between a cold jet and a warm steel element (e.g. a buffer tank wall or a transfer line vacuum vessel wall) may result in an excessive localisation of thermal strains and stresses. The objective of the analysis is to get a combined (analytical and experimental) one-dimensional model of a cryogenic jet that will enable estimation of heat transfer intensity between the jet and steel plate with a suitable accuracy for engineering applications. The jet diameter can only be determined experimentally. The mean velocity profile can be calculated from the fact that the total flux of momentum along the jet axis is conserved. The proposed model allows deriving the jet crown area with respect to the distance from the vent and the mean veloc...

  3. Relativistic AGN jets I. The delicate interplay between jet structure, cocoon morphology and jet-head propagation

    NARCIS (Netherlands)

    Walg, S.; Achterberg, A.; Markoff, S.; Keppens, R.; Meliani, Z.

    2013-01-01

    Astrophysical jets reveal strong signs of radial structure. They suggest that the inner region of the jet, the jet spine, consists of a low-density, fast-moving gas, while the outer region of the jet consists of a more dense and slower moving gas, called the jet sheath. Moreover, if jets carry angul

  4. The dental water jet: a product ahead of its time.

    Science.gov (United States)

    Ciancio, Sebastian G

    2009-03-01

    The dental water jet was invented by Dr. Gerald Moyer, a dentist, and John Mattingly, an engineer, in Ft. Collins, Colorado, in the late 1950s. The dental water jet, also known as an oral irrigator, was introduced to the dental profession in Texas during the 1962 Dallas Dental Convention. Numerous studies measuring the irrigator's efficacy in different cohorts have been published in peer-reviewed journals. The results of those studies are discussed in this article. The bulk of research has been conducted on one product (Waterpik dental water jet, Water Pik, Inc, Fort Collins, CO). This article is designed to provide dental professionals with the evidence essential to making an informed decision on the oral health benefits and expected outcomes of the dental water jet.

  5. Gravitational Waves of Jet Precession in Gamma-ray Bursts

    CERN Document Server

    Sun, Mou-Yuan; Gu, Wei-Min; Lu, Ju-Fu

    2012-01-01

    The physical nature of gamma-ray bursts (GRBs) are believed to involve an ultra-relativistic jet. The observed complex structure of light curves motivate the idea of jet precession. In this work, we study the gravitational waves of jet precession based on neutrino-dominated accretion disks around black holes, which may account for the central engine of GRBs. In our model, the jet and the inner part of the disk may precess along with the black hole, which is driven by the outer part of the disk. Gravitational waves are therefore expected to be significant from this black hole-inner disk precession system. By comparing our numerical results with the sensitivity of some detectors, we find that it is possible for DECIGO and BBO to detect such gravitational waves, particularly for GRBs in the Local Group.

  6. The supernova-gamma-ray burst-jet connection.

    Science.gov (United States)

    Hjorth, Jens

    2013-06-13

    The observed association between supernovae and gamma-ray bursts represents a cornerstone in our understanding of the nature of gamma-ray bursts. The collapsar model provides a theoretical framework for this connection. A key element is the launch of a bipolar jet (seen as a gamma-ray burst). The resulting hot cocoon disrupts the star, whereas the (56)Ni produced gives rise to radioactive heating of the ejecta, seen as a supernova. In this discussion paper, I summarize the observational status of the supernova-gamma-ray burst connection in the context of the 'engine' picture of jet-driven supernovae and highlight SN 2012bz/GRB 120422A--with its luminous supernova but intermediate high-energy luminosity--as a possible transition object between low-luminosity and jet gamma-ray bursts. The jet channel for supernova explosions may provide new insights into supernova explosions in general.

  7. Jet Substructure by Accident

    CERN Document Server

    Cohen, Timothy; Lisanti, Mariangela; Lou, Hou Keong

    2012-01-01

    We propose a new search strategy for high-multiplicity hadronic final states. When new particles are produced at threshold, the distribution of their decay products is approximately isotropic. If there are many partons in the final state, it is likely that several will be clustered into the same large-radius jet. The resulting jet exhibits substructure, even though the parent states are not boosted. This "accidental" substructure is a powerful discriminant against background because it is more pronounced for high-multiplicity signals than for QCD multijets. We demonstrate how to take advantage of accidental substructure to reduce backgrounds without relying on the presence of missing energy. As an example, we present the expected limits for several R-parity violating gluino decay topologies. This approach allows for the determination of QCD backgrounds using data-driven methods, which is crucial for the feasibility of any search that targets signatures with many jets and suppressed missing energy.

  8. Multichannel discharge between jet electrolyte cathode and jet electrolyte anode

    NARCIS (Netherlands)

    Shakirova, E. F.; Gaitsin, Al. F.; Son, E. E.

    2011-01-01

    We present the results of an experimental study of multichannel discharge between a jet electrolyte cathode and jet electrolyte anode within a wide range of parameters. We pioneer the reveal of the burning particularities and characteristics of multichannel discharge with jet electrolyte and droplet

  9. Relativistic AGN jets I. The delicate interplay between jet structure, cocoon morphology and jet-head propagation

    Science.gov (United States)

    Walg, S.; Achterberg, A.; Markoff, S.; Keppens, R.; Meliani, Z.

    2013-08-01

    Astrophysical jets reveal strong signs of radial structure. They suggest that the inner region of the jet, the jet spine, consists of a low-density, fast-moving gas, while the outer region of the jet consists of a more dense and slower moving gas, called the jet sheath. Moreover, if jets carry angular momentum, the resultant centrifugal forces lead to a radial stratification. Current observations are not able to fully resolve the radial structure, so little is known about its actual profile. We present three active galactic nuclei jet models in 2.5D of which two have been given a radial structure. The first model is a homogeneous jet, the only model that does not carry angular momentum; the second model is a spine-sheath jet with an isothermal equation of state; and the third jet model is a (piecewise) isochoric spine-sheath jet, with constant but different densities for jet spine and jet sheath. In this paper, we look at the effects of radial stratification on jet integrity, mixing between the different jet components and global morphology of the jet-head and surrounding cocoon. We consider steady jets that have been active for 23 Myr. All jets have developed the same number of strong internal shocks along their jet axis at the final time of simulation. These shocks arise when vortices are being shed by the jet-head. We find that all three jets maintain their stability all the way up to the jet-head. The isothermal jet maintains part of its structural integrity at the jet-head where the distinction between jet spine and jet sheath material can still be made. In this case, mixing between jet spine and jet sheath within the jet is fairly inefficient. The isochoric jet, on the other hand, loses its structural jet integrity fairly quickly after the jet is injected. At its jet-head, little structure is maintained and the central part of the jet predominantly consists of jet sheath material. In this case, jet spine and jet sheath material mix efficiently within the jet

  10. Resolving boosted jets with XCone

    Energy Technology Data Exchange (ETDEWEB)

    Thaler, Jesse; Wilkason, Thomas F. [Center for Theoretical Physics, Massachusetts Institute of Technology,Cambridge, MA, 02139 (United States)

    2015-12-09

    We show how the recently proposed XCone jet algorithm http://dx.doi.org/10.1007/JHEP11(2015)072 smoothly interpolates between resolved and boosted kinematics. When using standard jet algorithms to reconstruct the decays of hadronic resonances like top quarks and Higgs bosons, one typically needs separate analysis strategies to handle the resolved regime of well-separated jets and the boosted regime of fat jets with substructure. XCone, by contrast, is an exclusive cone jet algorithm that always returns a fixed number of jets, so jet regions remain resolved even when (sub)jets are overlapping in the boosted regime. In this paper, we perform three LHC case studies — dijet resonances, Higgs decays to bottom quarks, and all-hadronic top pairs — that demonstrate the physics applications of XCone over a wide kinematic range.

  11. Resolving boosted jets with XCone

    Science.gov (United States)

    Thaler, Jesse; Wilkason, Thomas F.

    2015-12-01

    We show how the recently proposed XCone jet algorithm [1] smoothly interpolates between resolved and boosted kinematics. When using standard jet algorithms to reconstruct the decays of hadronic resonances like top quarks and Higgs bosons, one typically needs separate analysis strategies to handle the resolved regime of well-separated jets and the boosted regime of fat jets with substructure. XCone, by contrast, is an exclusive cone jet algorithm that always returns a fixed number of jets, so jet regions remain resolved even when (sub)jets are overlapping in the boosted regime. In this paper, we perform three LHC case studies — dijet resonances, Higgs decays to bottom quarks, and all-hadronic top pairs — that demonstrate the physics applications of XCone over a wide kinematic range.

  12. Resolving Boosted Jets with XCone

    CERN Document Server

    Thaler, Jesse

    2015-01-01

    We show how the recently proposed XCone jet algorithm smoothly interpolates between resolved and boosted kinematics. When using standard jet algorithms to reconstruct the decays of hadronic resonances like top quarks and Higgs bosons, one typically needs separate analysis strategies to handle the resolved regime of well-separated jets and the boosted regime of fat jets with substructure. XCone, by contrast, is an exclusive cone jet algorithm that always returns a fixed number of jets, so jet regions remain resolved even when (sub)jets are overlapping in the boosted regime. In this paper, we perform three LHC case studies---dijet resonances, Higgs decays to bottom quarks, and all-hadronic top pairs---that demonstrate the physics applications of XCone over a wide kinematic range.

  13. Structural Transition in the NGC 6251 Jet: an Interplay with the Supermassive Black Hole and Its Host Galaxy

    Science.gov (United States)

    Tseng, Chih-Yin; Asada, Keiichi; Nakamura, Masanori; Pu, Hung-Yi; Algaba, Juan-Carlos; Lo, Wen-Ping

    2016-12-01

    The structure of the NGC 6251 jet on the milliarcsecond scale is investigated using images taken with the European VLBI Network and the Very Long Baseline Array. We detect a structural transition of the jet from a parabolic to a conical shape at a distance of (1-2) × 105 times the Schwarzschild radius from the central engine, which is close to the sphere of gravitational influence of the supermassive black hole (SMBH). We also examine the jet pressure profiles with the synchrotron minimum energy assumption to discuss the physical origin of the structural transition. The NGC 6251 jet, together with the M87 jet, suggests a fundamental process of structural transition in the jets of active galactic nuclei (AGNs). Collimated AGN jets are characterized by their external galactic medium, showing that AGN jets interplay with the SMBH and its host galaxy.

  14. Structural Transition in the NGC 6251 Jet: An Interplay with the Supermassive Black Hole and Its Host Galaxy

    CERN Document Server

    Tseng, Chih-Yin; Nakamura, Masanori; Pu, Hung-Yi; Algaba, Juan-Carlos; Lo, Wen-Ping

    2016-01-01

    The structure of the NGC 6251 jet at the milliarcsecond scale is investigated using the images taken with the European VLBI Network and the Very Long Baseline Array. We detect a structural transition of the jet from a parabolic to a conical shape at a distance of (1-2) x 10^5 times the Schwarzschild radius from the central engine, which is close to the sphere of gravitational influence (SGI) of the supermassive black hole (SMBH). We also examine the jet pressure profiles with the synchrotron minimum energy assumption to discuss the physical origin of the structural transition. The NGC 6251 jet, together with the M 87 jet, suggests a fundamental process of the structural transition in active galactic nuclei (AGN) jets. The collimated AGN jets are characterized by their external galactic medium, showing that AGN jets interplay with the SMBH and its host galaxy.

  15. Jet Photoproduction at THERA

    OpenAIRE

    Klasen, M.

    2001-01-01

    We demonstrate that a future high-energy electron-proton collider like THERA could largely extend the current HERA program in jet photoproduction of testing QCD and determining the partonic structure of the proton and the photon. Depending on the electron beam energy (250-500 GeV) and the collider mode ($ep$ or $\\gamma p$), the range in the hard transverse energy scale of the jets could be increased by a factor of 2-3 and the reach in the momentum fraction $x$ of the partons in the proton or ...

  16. Jet Physics in ATLAS

    CERN Document Server

    Sandoval, C; The ATLAS collaboration

    2012-01-01

    Measurements of hadronic jets provide tests of strong interactions which are interesting both in their own right and as backgrounds to many New Physics searches. It is also through tests of Quantum Chromodynamics that new physics may be discovered. The extensive dataset recorded with the ATLAS detector throughout the 7 TeV centre-of-mass LHC operation period allows QCD to be probed at distances never reached before. We present a review of selected ATLAS jet physics measurements. These measurements constitute precision tests of QCD in a new energy regime, and show sensitivity to the parton densities in the proton and to the value of the strong coupling, alpha_s.

  17. OPAL Jet Chamber Prototype

    CERN Multimedia

    OPAL was one of the four experiments installed at the LEP particle accelerator from 1989 - 2000. OPAL's central tracking system consists of (in order of increasing radius) a silicon microvertex detector, a vertex detector, a jet chamber, and z-chambers. All the tracking detectors work by observing the ionization of atoms by charged particles passing by: when the atoms are ionized, electrons are knocked out of their atomic orbitals, and are then able to move freely in the detector. These ionization electrons are detected in the dirfferent parts of the tracking system. This piece is a prototype of the jet chambers

  18. On the afterglow from the receding jet of γ-ray bursts

    Science.gov (United States)

    Wang, X.; Huang, Y. F.; Kong, S. W.

    2009-10-01

    According to popular progenitor models of gamma-ray bursts, twin jets should be launched by the central engine, with a forward jet moving toward the observer and a receding jet (or the counter jet) moving backwardly. However, in calculating the afterglows, usually only the emission from the forward jet is considered. Here we present a detailed numerical study on the afterglow from the receding jet. Our calculation is based on a generic dynamical description, and includes some delicate ingredients such as the effect of the equal arrival time surface. It is found that the emission from the receding jet is generally rather weak. In radio bands, it usually peaks at a time t ≥ 1000 d, with the peak flux nearly 4 orders of magnitude lower than the peak flux of the forward jet. Also, it usually manifests as a short plateau in the total afterglow light curve, but not as an obvious rebrightening as once expected. In optical bands, the contribution from the receding jet is even weaker, with the peak flux being ~23 mag lower than the peak flux of the forward jet. We thus argue that the emission from the receding jet is very difficult to detect. However, in some special cases, i.e., when the circum-burst medium density is very high, or if the parameters of the receding jet are quite different from those of the forward jet, the emission from the receding jet can be significantly enhanced and may still emerge as a marked rebrightening. We suggest that the search for receding jet emission should mostly concentrate on nearby gamma-ray bursts, and the observation campaign should last for at least several hundred days for each event.

  19. Studies of ultracompact jets with space VLBI

    Science.gov (United States)

    Lobanov, Andrei

    Imaging and polarimetry of radio emission on microarcsecond scales provided by VSOP-2 and RadioAstron will offer a range of possibilities for studying ultracompact regions of relativistic jets and extreme vicinity of the central supermassive bodies in AGN. Both missions will address a number of outstanding problems in AGN physics, including the site and the mechanism of jet formation, acceleration of relativistic flows, structure of magnetic field in the vicinity of the central engine of AGN, and the fundamental question of the physical nature of the central massive objects in galaxies. Combining space VLBI observations with variability studies made in the X-ray, and gamma-ray bands will enable locating accurately the sites of high-enenrgy continuum production in AGN. Prospects and potentials of these lines of study with space VLBI will be reviewed.

  20. Numerical Modelling of Jets and Plumes

    DEFF Research Database (Denmark)

    Larsen, Torben

    1993-01-01

    An overview on numerical models for prediction of the flow and mixing processes in turbulent jets and plumes is given. The overview is structured to follow an increasing complexity in the physical and numerical principles. The various types of models are briefly mentioned, from the one-dimensiona......An overview on numerical models for prediction of the flow and mixing processes in turbulent jets and plumes is given. The overview is structured to follow an increasing complexity in the physical and numerical principles. The various types of models are briefly mentioned, from the one......-dimensional integral method to the general 3-dimensional solution of the Navier-Stokes equations. Also the predictive capabilities of the models are discussed. The presentation takes the perspective of civil engineering and covers issues like sewage outfalls and cooling water discharges to the sea....

  1. Exo-Skeletal Engine: Novel Engine Concept

    Science.gov (United States)

    Chamis, Cristos C.; Blankson, Isaiah M.

    2004-01-01

    The exo-skeletal engine concept represents a new radical engine technology with the potential to substantially revolutionize engine design. It is an all-composite drum-rotor engine in which conventionally heavy shafts and discs are eliminated and are replaced by rotating casings that support the blades in spanwise compression. Thus the rotating blades are in compression rather than tension. The resulting open channel at the engine centerline has immense potential for jet noise reduction and can also accommodate an inner combined-cycle thruster such as a ramjet. The exo-skeletal engine is described in some detail with respect to geometry, components, and potential benefits. Initial evaluations and results for drum rotors, bearings, and weights are summarized. Component configuration, assembly plan, and potential fabrication processes are also identified. A finite element model of the assembled engine and its major components is described. Preliminary results obtained thus far show at least a 30-percent reduction of engine weight and about a 10-dB noise reduction, compared with a baseline conventional high-bypass-ratio engine. Potential benefits in all aspects of this engine technology are identified and tabulated. Quantitative assessments of potential benefits are in progress.

  2. Jet substructure using semi-inclusive jet functions within SCET

    CERN Document Server

    Kang, Zhong-Bo; Vitev, Ivan

    2016-01-01

    We propose a new method to evaluate jet substructure observables in inclusive jet measurements based upon semi-inclusive jet functions within the framework of Soft Collinear Effective Theory (SCET). In this work we consider the jet fragmentation function, where a hadron $h$ is identified inside a fully reconstructed jet as a first example. We introduce a new semi-inclusive fragmenting jet function ${\\mathcal G}^h_i(z= \\omega_J/\\omega,z_h=\\omega_h/\\omega_J,\\omega_J, R,\\mu)$ which depends on the jet radius $R$ and the large light-cone momenta of the parton '$i$' initiating the jet ($\\omega$), the jet ($\\omega_J$), and the hadron $h$ ($\\omega_h$). We are then able to express the jet fragmentation function as a semi-inclusive jet observable rather than as an exclusive one, which is closer to the actual experimental measurements. We demonstrate the consistency of the effective field theory treatment and standard perturbative QCD calculations at next-to-leading order (NLO). We further derive the renormalization gro...

  3. Intermonsoonal equatorial jets

    Digital Repository Service at National Institute of Oceanography (India)

    Muraleedharan, P.M.

    Three transects each from the cruises of R V Pioneer (84 , 88 degrees and 92 degrees E) during May-June 1964 and R V Vityaz (77 , 84 degrees and 94 degrees E) during October-November 1962 were used to compare pre and postmonsoon equatorial jets...

  4. Fluid Jet Polishing

    NARCIS (Netherlands)

    Booij, S.M.

    2003-01-01

    The goal of this thesis research was to investigate the possibilities and limitations of the Fluid Jet Polishing (FJP) technique. FJP is a new optical fabrication technique that is capable of making shape corrections and reducing the surface roughness of glass and other materials. The principle of o

  5. Fluid Jet Polishing

    NARCIS (Netherlands)

    Booij, S.M.

    2003-01-01

    The goal of this thesis research was to investigate the possibilities and limitations of the Fluid Jet Polishing (FJP) technique. FJP is a new optical fabrication technique that is capable of making shape corrections and reducing the surface roughness of glass and other materials. The principle of

  6. Jet-Images: Computer Vision Inspired Techniques for Jet Tagging

    CERN Document Server

    Cogan, Josh; Strauss, Emanuel; Schwarztman, Ariel

    2014-01-01

    We introduce a novel approach to jet tagging and classification through the use of techniques inspired by computer vision. Drawing parallels to the problem of facial recognition in images, we define a jet-image using calorimeter towers as the elements of the image and establish jet-image preprocessing methods. For the jet-image processing step, we develop a discriminant for classifying the jet-images derived using Fisher discriminant analysis. The effectiveness of the technique is shown within the context of identifying boosted hadronic W boson decays with respect to a background of quark- and gluon- initiated jets. Using Monte Carlo simulation, we demonstrate that the performance of this technique introduces additional discriminating power over other substructure approaches, and gives significant insight into the internal structure of jets.

  7. Jet-images: computer vision inspired techniques for jet tagging

    Energy Technology Data Exchange (ETDEWEB)

    Cogan, Josh; Kagan, Michael; Strauss, Emanuel; Schwarztman, Ariel [SLAC National Accelerator Laboratory,Menlo Park, CA 94028 (United States)

    2015-02-18

    We introduce a novel approach to jet tagging and classification through the use of techniques inspired by computer vision. Drawing parallels to the problem of facial recognition in images, we define a jet-image using calorimeter towers as the elements of the image and establish jet-image preprocessing methods. For the jet-image processing step, we develop a discriminant for classifying the jet-images derived using Fisher discriminant analysis. The effectiveness of the technique is shown within the context of identifying boosted hadronic W boson decays with respect to a background of quark- and gluon-initiated jets. Using Monte Carlo simulation, we demonstrate that the performance of this technique introduces additional discriminating power over other substructure approaches, and gives significant insight into the internal structure of jets.

  8. Acoustic measurements of models of military style supersonic nozzle jets

    NARCIS (Netherlands)

    Kuo, C.W.; Veltin, J.; McLaughlin, D.K.

    2014-01-01

    Modern military aircraft jet engines are designed with variable-geometry nozzles to provide optimal thrust in different operating conditions, depending on the flight envelope. However, acoustic measurements for such nozzles are scarce, due to the cost involved in making full-scale measurements and

  9. Acoustic measurements of models of military style supersonic nozzle jets

    NARCIS (Netherlands)

    Kuo, C.W.; Veltin, J.; McLaughlin, D.K.

    2014-01-01

    Modern military aircraft jet engines are designed with variable-geometry nozzles to provide optimal thrust in different operating conditions, depending on the flight envelope. However, acoustic measurements for such nozzles are scarce, due to the cost involved in making full-scale measurements and t

  10. Jet substructure using semi-inclusive jet functions in SCET

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Zhong-Bo [Theoretical Division, Los Alamos National Laboratory,Los Alamos, NM 87545 (United States); Department of Physics and Astronomy, University of California,Los Angeles, CA 90095 (United States); Ringer, Felix; Vitev, Ivan [Theoretical Division, Los Alamos National Laboratory,Los Alamos, NM 87545 (United States)

    2016-11-25

    We propose a new method to evaluate jet substructure observables in inclusive jet measurements, based upon semi-inclusive jet functions in the framework of Soft Collinear Effective Theory (SCET). As a first example, we consider the jet fragmentation function, where a hadron h is identified inside a fully reconstructed jet. We introduce a new semi-inclusive fragmenting jet function G{sub i}{sup h}(z=ω{sub J}/ω,z{sub h}=ω{sub h}/ω{sub J},ω{sub J},R,μ), which depends on the jet radius R and the large light-cone momenta of the parton ‘i’ initiating the jet (ω), the jet (ω{sub J}), and the hadron h (ω{sub h}). The jet fragmentation function can then be expressed as a semi-inclusive observable, in the spirit of actual experimental measurements, rather than as an exclusive one. We demonstrate the consistency of the effective field theory treatment and standard perturbative QCD calculations of this observable at next-to-leading order (NLO). The renormalization group (RG) equation for the semi-inclusive fragmenting jet function G{sub i}{sup h}(z,z{sub h},ω{sub J},R,μ) are also derived and shown to follow exactly the usual timelike DGLAP evolution equations for fragmentation functions. The newly obtained RG equations can be used to perform the resummation of single logarithms of the jet radius parameter R up to next-to-leading logarithmic (NLL{sub R}) accuracy. In combination with the fixed NLO calculation, we obtain NLO+NLL{sub R} results for the hadron distribution inside the jet. We present numerical results for pp→(jet h)X in the new framework, and find excellent agreement with existing LHC experimental data.

  11. Relativistic AGN jets II. Jet properties and mixing effects for episodic jet activity

    CERN Document Server

    Walg, Sander; Markoff, Sera; Keppens, Rony; Porth, Oliver

    2013-01-01

    Various radio galaxies show signs of having gone through episodic jet outbursts in the past. An example is the class of double-double radio galaxies (DDRGs). However, to follow the evolution of an individual source in real-time is impossible due to the large time scales involved. Numerical studies provide a powerful tool to investigate the temporal behavior of episodic jet outbursts in a (magneto-)hydrodynamical setting. We simulate the injection of two jets from active galactic nuclei (AGN), separated by a short interruption time. Three different jet models are compared. We find that an AGN jet outburst cycle can be divided into four phases. The most prominent phase occurs when the restarted jet is propagating completely inside the hot and inflated cocoon left behind by the initial jet. In that case, the jet-head advance speed of the restarted jet is significantly higher than the initial jet-head. While the head of the initial jet interacts strongly with the ambient medium, the restarted jet propagates almos...

  12. Real vs. simulated relativistic jets

    CERN Document Server

    Gómez, J L; Agudo, I; Marscher, A P; Jorstad, S G; Aloy, M A

    2005-01-01

    Intensive VLBI monitoring programs of jets in AGN are showing the existence of intricate emission patterns, such as upstream motions or slow moving and quasi-stationary componentes trailing superluminal features. Relativistic hydrodynamic and emission simulations of jets are in very good agreement with these observations, proving as a powerful tool for the understanding of the physical processes taking place in the jets of AGN, microquasars and GRBs. These simulations show that the variability of the jet emission is the result of a complex combination of phase motions, viewing angle selection effects, and non-linear interactions between perturbations and the underlying jet and/or ambient medium. Both observations and simulations suggest that shock-in-jet models may be an overly simplistic idealization when interpreting the emission structure observed in actual jets.

  13. Turbulent jet in confined counterflow

    Indian Academy of Sciences (India)

    M Sivapragasam; M D Deshpande; S Ramamurthy; P White

    2014-06-01

    The mean flowfield of a turbulent jet issuing into a confined, uniform counterflow was investigated computationally. Based on dimensional analysis, the jet penetration length was shown to scale with jet-to-counterflow momentum flux ratio. This scaling and the computational results reproduce the well-known correct limit of linear growth of the jet penetration length for the unconfined case when the momentum flux ratio is small. However, for the high momentum flux ratio case corresponding to the confinement, the jet penetration length is shown to reach an asymptotic limit of about 3.57 times the confining duct diameter. This conclusion is contrary to the existing results which predict indefinite growth. A simple modification of an existing similarity solution for the jet in an unconfined counterflow provides a convenient framework for presenting the results of the flowfield and jet penetration length.

  14. Pileup subtraction for jet shapes.

    Science.gov (United States)

    Soyez, Gregory; Salam, Gavin P; Kim, Ji-Hun; Dutta, Souvik; Cacciari, Matteo

    2013-04-19

    Jets in high energy hadronic collisions often contain the fingerprints of the particles that produced them. Those fingerprints, and thus the nature of the particles that produced the jets, can be read off with the help of quantities known as jet shapes. Jet shapes are, however, severely affected by pileup, the accumulation in the detector of the residues of the many simultaneous collisions taking place in the Large Hadron Collider (LHC). We introduce a method to correct for pileup effects in jet shapes. Relative to earlier, limited approaches, the key advance resides in its full generality, achieved through a numerical determination, for each jet, of a given shape's susceptibility to pileup. The method rescues the possibility of using jet shapes in the high pileup environment of current and future LHC running, as we show with examples of quark-gluon discrimination and top tagging.

  15. Modelling of flow within a vaned channel in thermal engine; Modelisation d'un jet au sein d'un canal inter-aube de machine thermique

    Energy Technology Data Exchange (ETDEWEB)

    Georges Descombes; Fadila Maroteaux; Jacques Jullien; Michel Pluviose [Laboratoire de mecanique physique, Universite Pierre et Marie Curie, UMR 7068, 2, place de la gare de ceinture 78210 Saint Cyr l' Ecole (France)

    2005-10-01

    The results of study concerning energy transformation within the variable geometry nozzle of a turbo-charger are presented in this paper. A detailed analysis is carried out in order to study the effect of losses on the permeability characteristics of the vaned channel, and to observe the flow-turbine structure interaction resulting at the rotor. Particular attention is paid to the local jet structure at outlet from the variable geometry channel when sonic conditions are likely to be reached at the diffuser throat. A supersonic flow layer can be observed in the mixing zone at the rotor inlet, this phenomenon generates high losses in this region. (authors)

  16. Analysis of gas jetting and fumarole acoustics at Aso Volcano, Japan

    Science.gov (United States)

    McKee, Kathleen; Fee, David; Yokoo, Akihiko; Matoza, Robin S.; Kim, Keehoon

    2017-06-01

    The gas-thrust region of a large volcanic eruption column is predominately a momentum-driven, fluid flow process that perturbs the atmosphere and produces sound akin to noise from jet and rocket engines, termed ;jet noise;. We aim to enhance understanding of large-scale volcanic jets by studying an accessible, less hazardous fumarolic jet. We characterize the acoustic signature of 2.5-meter wide vigorously jetting fumarole at Aso Volcano, Japan using a 5-element infrasound array located on the nearby crater. The fumarole opened on 13 July 2015 on the southwest flank of the partially collapsed pyroclastic cone within Aso Volcano's Naka-dake crater and had persistent gas jetting, which produced significant audible jet noise. The array was 220 m from the fumarole and 57.6° from the vertical jet axis, a recording angle not typically feasible in volcanic environments. Array processing is performed to distinguish fumarolic jet noise from wind. Highly correlated periods are characterized by sustained, low-amplitude signal with a 7-10 Hz spectral peak. Finite difference time domain method numerical modeling suggests the influence of topography near the vent and along the propagation path significantly affects the spectral content, complicating comparisons with laboratory jet noise. The fumarolic jet has a low estimated Mach number (0.3 to 0.4) and measured temperature of 260 °C. The Strouhal number for infrasound from volcanic jet flows and geysers is not known; thus we assume a peak Strouhal number of 0.19 based on pure-air laboratory jet experiments. This assumption leads to an estimated exit velocity of the fumarole of 79 to 132 m/s. Using published gas composition data from 2003 to 2009, the fumarolic vent area estimated from thermal infrared images, and estimated jet velocity, we estimate total volatile flux at 160-270 kg/s (14,000-23,000 t/d).

  17. Analysis of gas jetting and fumarole acoustics at Aso Volcano, Japan

    Energy Technology Data Exchange (ETDEWEB)

    McKee, Kathleen; Fee, David; Yokoo, Akihiko; Matoza, Robin S.; Kim, Keehoon

    2017-06-01

    The gas-thrust region of a large volcanic eruption column is predominately a momentum-driven, fluid flow process that perturbs the atmosphere and produces sound akin to noise from jet and rocket engines, termed “jet noise”. We aim to enhance understanding of large-scale volcanic jets by studying an accessible, less hazardous fumarolic jet. We characterize the acoustic signature of ~ 2.5-meter wide vigorously jetting fumarole at Aso Volcano, Japan using a 5-element infrasound array located on the nearby crater. The fumarole opened on 13 July 2015 on the southwest flank of the partially collapsed pyroclastic cone within Aso Volcano's Naka-dake crater and had persistent gas jetting, which produced significant audible jet noise. The array was ~ 220 m from the fumarole and 57.6° from the vertical jet axis, a recording angle not typically feasible in volcanic environments. Array processing is performed to distinguish fumarolic jet noise from wind. Highly correlated periods are characterized by sustained, low-amplitude signal with a 7–10 Hz spectral peak. Finite difference time domain method numerical modeling suggests the influence of topography near the vent and along the propagation path significantly affects the spectral content, complicating comparisons with laboratory jet noise. The fumarolic jet has a low estimated Mach number (0.3 to 0.4) and measured temperature of ~ 260 °C. The Strouhal number for infrasound from volcanic jet flows and geysers is not known; thus we assume a peak Strouhal number of 0.19 based on pure-air laboratory jet experiments. This assumption leads to an estimated exit velocity of the fumarole of ~ 79 to 132 m/s. Using published gas composition data from 2003 to 2009, the fumarolic vent area estimated from thermal infrared images, and estimated jet velocity, we estimate total volatile flux at ~ 160–270 kg/s (14,000–23,000 t/d).

  18. Engineering electromagnetics

    CERN Document Server

    Thomas, David T; Hartnett, James P; Hughes, William F

    1973-01-01

    The applications involving electromagnetic fields are so pervasive that it is difficult to estimate their contribution to the industrial output: generation of electricity, power transmission lines, electric motors, actuators, relays, radio, TV and microwave transmission and reception, magnetic storage, and even the mundane little magnet used to hold a paper note on the refrigerator are all electromagnetic in nature. One would be hard pressed to find a device that works without relaying on any electromagnetic principle or effect. This text provides a good theoretical understanding of the electromagnetic field equations but also treats a large number of applications. In fact, no topic is presented unless it is directly applicable to engineering design or unless it is needed for the understanding of another topic. In electrostatics, for example, the text includes discussions of photocopying, ink-jet printing, electrostatic separation and deposition, sandpaper production, paint spraying, and powder coating. In ma...

  19. Expected performance of ATLAS for measurements of jets, b-jets, tau-jets, and ETmis

    CERN Document Server

    Sapinski, M

    2002-01-01

    Jets and missing energy are among the most important objects of LHC physics. The accuracy of measurements of missing energy and direction and energy of jets put strong requirements on the detector performance. These requirements and the ATLAS Calorimeter system which is projected to fulfill these requirements are presented. The jet reconstruction algorithms and jet energy scale calibration are shortly discussed. Forward jet tagging, b-tagging and tau-tagging are important issues of many physical analyses. Reconstruction of resonances is an example of complex use of calorimeter performance

  20. Description of the ATLAS jet veto measurement and jet gap jet events at hadronic colliders

    CERN Document Server

    Royon, C

    2014-01-01

    We present a new QCD description of the ATLAS jet veto measurement, using the Banfi- Marchesini-Smye equation to constrain the inter-jet QCD radiation. This equation resums emis- sions of soft gluons at large angles and leads to a very good description of data. We also investigate jet gap jet events in hadron-hadron collisions, in which two jets are produced and separated by a large rapidity gap. Using a renormalisation-group improved NLL kernel implemented in the HERWIG Monte Carlo program, we show that the BFKL predictions are in good agreement with the Tevatron data, and present predictions that could be tested at the LHC.