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Showing papers on "Afterburner published in 2009"


Patent
23 Sep 2009
TL;DR: In this article, a two-stage turbocharger was used to extract excess power from the exhaust of a hydrogen-fueled powerplant, and a control system controlled the operation of the motor-generator to maintain the engine at a speed selected based on controlling the engine equivalence ratio.
Abstract: A hydrogen fueled powerplant including an internal combustion engine that drives a motor-generator, and has a two-stage turbocharger, for an aircraft. A control system controls the operation of the motor-generator to maintain the engine at a speed selected based on controlling the engine equivalence ratio. The control system controls an afterburner, an intercooler and an aftercooler to maximize powerplant efficiency. The afterburner also adds power to the turbochargers during high-altitude restarts. The turbochargers also include motor-generators that extract excess power from the exhaust.

50 citations


Journal ArticleDOI
TL;DR: In this article, the authors report results of a study to advance the methods used for detailed characterization of military aircraft emissions, and provide emission factors for two aircraft: the F-15 fighter and the C-130 cargo plane.

27 citations


Journal ArticleDOI
TL;DR: In this article, a gas-fed internal reforming solid oxide fuel cell system with ejector, heater exchanger and afterburner is presented, and a parametric analysis is performed to evaluate the effect of various parameters such as the current density, operating temperature, the operating pressure, the fuel utilization factor, the air utilization factor and the S/C ratio on system performance.
Abstract: The aim of this work is to analyze nature gas-fed internal reforming solid oxide fuel cell system. The system consists of ejector, heater exchanger, solid oxide fuel cell (anode and cathode) and afterburner, and models by Aspen PlusTM. A parametric analysis also performed to evaluate the effect of various parameters such as the current density, the operating temperature, the operating pressure, the fuel utilization factor, the air utilization factor and the S/C ratio on system performance.

23 citations


Journal ArticleDOI
TL;DR: In this article, a simulation of a hybrid solid oxide fuel cell-gas turbine (SOFC-GT) power generation system fueled by natural gas is presented, and the relevant plant performance indicators have been analyzed to evaluate the incremental increase in efficiency brought about by the introduction of the gas turbine and heat regeneration system.
Abstract: The paper presents a simulation of a hybrid solid oxide fuel cell-gas turbine (SOFC-GT) power generation system fueled by natural gas. In the system considered, the unreacted fuel from a topping solid oxide fuel cell is burnt in an afterburner to feed a bottoming gas turbine and produce additional power. Combustion gas expands in the gas turbine after having preheated the inlet air and fuel and it is used to generate steam required by the reforming reactions. A novel thermodynamic model has been developed for the fuel cell and implemented into the library of a modular object-oriented Process Simulator, CAMELPro™. The relevant plant performance indicators have been analyzed to evaluate the incremental increase in efficiency brought about by the introduction of the gas turbine and heat regeneration system. Simulations were performed for different values of the main plant parameters. This paper is an updated version of a paper published in the ECOS'08 proceedings.

14 citations


Journal ArticleDOI
TL;DR: In this paper, the transient behavior of an oxygen mixed conducting membrane (OMCM)-based gas turbine (GT) power plant is investigated for part-load operation and two strategies are analyzed: (i) reduction in mass flow of air to the GT in conjunction with reduced fuel supply to the afterburner while keeping the turbine exit temperature (TET) constant (TTE control strategy), and (ii) reduction of fuel supply at constant air supply to GT while the TET is allowed to vary (turbine inlet temperature (TIT) control strategy).

13 citations


Dissertation
01 Jan 2009
TL;DR: In this paper, an active control technique for high Re, high Mach number compressible jetflows is proposed, where a discrete number of small radially penetrating jets are introduced around the primary jet periphery at nozzle exit and the control jets may be steady or pulsed.
Abstract: The field of jet mixing enhancement has interested researchers for a long time because of its practical significance in many engineering areas: combustion, noise reduction, IR signature reduction. In the military aircraft context, the largest sources of IR radiation are the engine afterburner, propulsion nozzle, and jet exhaust plume, where gas and metal temperatures are highest. Rapid mixing of the jet plume with the ambient air offers a number of interesting possibilities for IR reduction, including noise reduction as an added benefit. Many techniques to achieve enhanced jet mixing have been proposed; all have limitations and no technique has been clearly proven to be optimum. An active control technique which has shown promise is the use of control jets - a discrete number of small radially penetrating jets introduced around the primary jet periphery at nozzle exit. The control jets may be steady or pulsed. However, the literature to date largely covers studies on control jet effectiveness at low Reynolds numbers and mostly under low Mach number, essentially incompressible, conditions - far removed from the regime of practical application. The fact that control jets can be designed according to requirements, and in particular can be turned off when not required, argues that this technique is worthy of further investigation, but with a specific emphasis on high Re, high Mach number compressible jet flows. This is the focus of the current study, which constituted both experimental and computational investigations. [Continues.]

3 citations


Jin Jie1
01 Jan 2009
TL;DR: In this article, two sets of propulsion concept were analyzed based the existent low bypass ratio augmented turbofan engine with mixed exhaust nozzle, in order to meet the mission requirements on the low Mach propulsion system (Ma≤3.5) in the hypersonic transportation.
Abstract: Two sets of propulsion concept were analyzed based the existent low bypass ratio augmented turbofan engine with mixed exhaust nozzle,in order to meet the mission requirements on the low Mach propulsion system(Ma≤3.5) in the hypersonic transportation.The result shows: as for the turbofan(TF) concept,by means of optimizing the control law of the base turbofan engine,total pressure difference between the two streams at the mixed zone was effectively reduced,contributing to flow organization at the afterburner inlet and flame stability.Also,the optimized control law contributes to lower specific fuel consumption.As for the turbofan/ramjet combined cycle engine concept with over-under configuration compared with the TF concept,independent inlet and nozzle were both required for the two engine models due to the aerodynamic mismatch during mode transition,which would increase the structure complexity,weight and technology risk.

3 citations


Proceedings ArticleDOI
05 Jan 2009
TL;DR: In this article, the authors discuss the relative importance of these reactant properties and points the way to a successful application of a Radical Jet Generator (RJG) based flame holder.
Abstract: Conventional flame holders in afterburners cause non-negligible stagnation pressure losses throughout a mission even though the afterburner is only in use for less than a minute at a time. In addition, the hot metal of the flame holder becomes a source of IR radiation that an enemy missile can hone in on throughout the flight. This makes the plasma based Radical Jet Generator (RJG) an attractive alternative, because it is only deployed while the afterburner is in use. The RJG consists of a cavity, which is supplied with a combustible gas mixture that is ignited with a high frequency (HF) spark. Hot combustion products carrying radicals that are generated by partial combustion in the cavity are injected through an orifice into a combustible main flow. There the hot, reacting jet stabilizes the main combustion process. To improve flame holding the jet must penetrate well into the main flow. This can be achieved by accelerating the flow through a small nozzle. Unfortunately, this causes a combustion instability in the cavity, which significantly affects the radical concentration and, hence, the flame holding capability of the jet. Careful examination of the processes in the RJG indicates that when a spark is first originated it creates a partially conducting channel that is convected downstream by the flow. As the spark path grows so does the breakdown voltage until the energy required to form as new, more direct spark path is lower than that for the extended channel. At that instant, a new spark channel is established and the process repeats. Direct observations have shown that each HF spark channel ignites a flame kernel that grows as it propagates downstream. This produces pockets of reactants separated by products, which propagate downstream. Once the velocity in the RJG exceeds the threshold required for the combustion process to become unstable its frequency depends only on the equivalence ratio in the RJG, and not on further changes in the flow velocity or in the frequency of the HF spark. While the flow speed determines the residence time in the reactor, the equivalence ratio affects the ignition delay time and the flame speed. The interplay of these reactant properties affects the frequency of the combustion instabilities. This paper discusses the relative importance of the above mechanisms and points the way to a successful application of a RJG based flame holder.

2 citations


Patent
20 Dec 2009
TL;DR: In this paper, the authors proposed an engine consisting of first and second stages, inner and after shafts with blower fitted on inner shaft, and compressor fitted on outer shaft, high and low-pressure turbines with cooling system, combustion chamber, heat exchanger and jet nozzle.
Abstract: FIELD: engines and pumps ^ SUBSTANCE: proposed engine comprises first and second stages, inner and after shafts with blower fitted on inner shaft, and compressor fitted on outer shaft, high- and low-pressure turbines with cooling system, combustion chamber, heat exchanger and jet nozzle Combustion chamber is arranged between compressor and high-pressure turbine Heat exchanger is mounted ahead of combustion chamber Note that additional compressor is arranged between high- and low-pressure turbines Heat exchanger-heater is mounted right behind said additional compressor to communicate, via hear carrier pipelines, with nuclear reactor Afterburner heat exchanger is arranged behind jet nozzle to communicate, also, with nuclear reactor ^ EFFECT: higher thrust in afterburning, increased efficiency and reliability ^ 3 cl, 4 dwg

2 citations


Patent
10 Jun 2009
TL;DR: In this article, a ring of nozzles is installed in the main flow and is made of ring sectors installed substantially in continuous sequence on blades of flame stabiliser and comprising fuel supply guide and collector chambers, and facilities for air supply in collector chambers and fuel to supply guide.
Abstract: FIELD: engines and pumps. ^ SUBSTANCE: device for supply of air and fuel to ring of nozzles in afterburner in double-circuit turbojet engine comprises multiple blades of flame stabiliser installed in afterburner and passing radially around chamber axis in the main flow from external body. Ring of nozzles is installed in the main flow and is made of ring sectors installed substantially in continuous sequence on blades of flame stabiliser and comprising fuel supply guide and collector chambers, and facilities for air supply in collector chambers and fuel to fuel supply guide. Facilities for air and fuel supply pass between ring of nozzles and external body of afterburner inside blades of flame stabiliser and are connected to collector chambers and fuel supply guide via ends of ring sectors. ^ EFFECT: increased efficiency of turbojet engine by means of main flow head losses limitation and by means of improvement of conditions, under which fuel is injected into main flow via ring of nozzles. ^ 9 cl, 6 dwg

1 citations


Journal ArticleDOI
TL;DR: In this article, the effects of nozzle scale, total temperature, and an afterburner on jet noise characteristics from a pre-cooled turbojet engine are investigated experimentally.
Abstract: 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.

Patent
18 Nov 2009
TL;DR: In this article, the authors propose a fuel cell system with at least one fuel cell, a gas generator, and an afterburner for providing reformate from a hydrocarbon-containing fuel.
Abstract: A fuel cell system has at least one fuel cell (12), a gas generating system (14) for providing the reformate from a hydrocarbon-containing fuel (16) and a in an exhaust line (42) downstream of the fuel cell (12), the afterburner (18) at least of a proportion of the exhaust gas of the fuel cell (12) is passed and are thermally reacted in the combustible constituents of the exhaust gas. It is an exhaust gas recirculation (20) downstream of the afterburner (18) to the input side (26) of the gas generating system (14), so that at least part of the exhaust gas is fed to the feed stream of the gas generating system (14). The fuel cell system (10; 10 ') is designed such that the entire operation in the fuel cell system (10; 10') of water required by the operation of the fuel cell system (10; 10 ') is provided in gaseous form.



Journal Article
TL;DR: In this paper, a comparative analysis of several combustion models indicated that there exist greater differences among them, and the combustion time was calculated by means of the Brooks model, and other parameters of the particle-trajectory models were obtained.
Abstract: It is very complex and difficult to measure combustion time of aluminum particles in steam.The comparative calculations of several combustion models indicated that there exist greater differences among them.Based on comparative analysis,the combustion time was calculated by means of Brooks model,and other parameters of the particle-trajectory models were obtained. The flow field of afterburner of a water ramjet was numerically simulated and the calculated temperature field was in agreement with the test results,which indicate that the method is feasible.The presented numerical models can be used as the references for combustion organizing study.

01 Jan 2009
TL;DR: In this article, a numerical simulation of turbulent combustion in the afterburner of a solid rocket ramjet was performed by applying the probability density function non-premixed mode, and the simulation results indicated that the afferburner has complicated three-dimensional chemical reaction flow and the effects of the nose backflow and axial swirl on the dilution combustion.
Abstract: The numerical simulation of turbulent combustion in the afterburner of solid rocket ramjet was performed by applying the probability density function non -premixed mode.The simulation results indicate that the afferburner has complicated three-dimensional chemical reaction flow and the effects of the nose backflow and axial swirl on the dilution combustion.In the afterburner,the complicated temperature distribution has close relation with the dilution,combustion and flow of the air and gas.The intensity of the gas backflow and axial swirl and the dilution in the afterburner are enhanced by increasing the air-to-fuel ratio,and then the combustion efficiency is improved.

Patent
01 Apr 2009
TL;DR: In this paper, a motor vehicle consisting of a reformer with a burner unit is described. But the afterburner unit is identical to the burner unit of the reformer.
Abstract: The Intention relates to a fuel cell system comprising a reformer with a burner unit for reacting fuel with oxidant in an exothermic oxidation reaction to form a product gas which downstream of the burner unit is mixable with additional fuel, the resulting gas mixture being reformable in the reformer into a reformate; a fuel cell stack for receiving a supply of the reformate; and an afterburner for receiving a supply of the substances reacted in the fuel cell stack, with a burner unit for reacting fuel with oxidant in an exothermic oxidation reaction. In accordance with the invention it is provided for the burner unit of the reformer is engineered identical to the burner unit of the afterburner. In addition, the invention relates to a motor vehicle comprising one such fuel cell system.