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Showing papers on "Afterburner published in 2004"


Proceedings ArticleDOI
11 Jul 2004
TL;DR: In this article, the afterburner on a modern aircraft gas turbine engine provides significant thrust augmentation critical to the performance and mission of tactical aircraft, and the authors describe some of the fundamental technical challenges being faced by augmentor designers.
Abstract: The afterburner on a modern aircraft gas turbine engine provides significant thrust augmentation critical to the performance and mission of tactical aircraft. Higher exhaust temperatures and survivability requirements for advanced aircraft have resulted in new constraints on the augmentor design which dramatically changes the design architecture. Many of the design methods established for afterburners over the past 50 years are insufficient for the augmentor configurations being developed today. This paper will describe some of the fundamental technical challenges being faced by augmentor designers, and will outline critical needs in terms of fundamental combustion sciences and engineering that needs to be acquired to support new design methods for advanced augmentors.

110 citations


01 Jan 2004
TL;DR: In this paper, the authors developed a dynamic SOFC/GT model and calibrated it with experimentally obtained data from a single-cell experiment performed on a Siemens Westinghouse tubular SOFC.
Abstract: This thesis focuses on three main areas within the field of SOFC/GT-technology:• Development of a dynamic SOFC/GT model• Model calibration and sensitivity study• Assessment of the dynamic properties of a SOFC/GT power plantThe SOFC/GT model developed in this thesis describes a pressurised tubular Siemens Westinghouse-type SOFC, which is integrated in a gas turbine cycle. The process further includes a plate-fin recuperator for stack air preheating, a prereformer, an anode exhaust gas recycling loop for steam/carbon-ratio control, an afterburner and a shell-tube heat exchanger for air preheating. The fuel cell tube, the recuperator and the shell-tube heat exchanger are spatially distributed models. The SOFC model is further thermally integrated with the prereformer. The compressor and turbine models are based on performance maps as a general representation of the characteristics. In addition, a shaft model which incorporates moment of inertia is included to account for gas turbine transients.The SOFC model is calibrated against experimentally obtained data from a single-cell experiment performed on a Siemens Westinghouse tubular SOFC. The agreement between the model and the experimental results is good. The sensitivity study revealed that the degree of prereforming is of great importance with respect to the axial temperature distribution of the fuel cell.Types of malfunctions are discussed prior to the dynamic behaviour study. The dynamic study of the SOFC/GT process is performed by simulating small and large load changes according to three different strategies;• Load change at constant mean fuel cell temperature• Load change at constant turbine inlet temperature• Load change at constant shaft speedOf these three strategies, the constant mean fuel cell temperature strategy appears to be the most rapid load change method. Furthermore, this strategy implies the lowest degree of thermal cycling, the smoothest fuel cell temperature distribution and the lowest current density at part-load. Thus, this strategy represents the overall lowest risk with respect to system malfunctions and degradation. In addition, the constant mean fuel cell temperature strategy facilitates high efficiency part-load operation. The constant turbine inlet temperature strategy proved to lead to unstable operation at low load, and thus it is considered to be the least adequate method for load change. For both the constant mean fuel cell temperature strategy and the constant TIT strategy, surge might be a problem for very large load reductions. The slowest response to load changes was found for the constant shaft speed strategy. Furthermore, this strategy leads to very low fuel cell temperatures at low loads. This in combination with a possible higher degradation rate makes the constant shaft speed strategy unsuited for large load variations. Nevertheless, operation at constant shaft speed may be facilitated by air bypass, VIGV or compressor blow off.

15 citations


Patent
19 May 2004
TL;DR: In this paper, a retractable afterburner cover for a jet engine has been proposed, which is affixed by a plurality of moveable support arms to the outer surface of the engine.
Abstract: The present invention is a retractable afterburner shroud for use upon a jet engine. The retractable shroud conforms to an outer surface of a jet engine. The afterburner shroud is affixed by a plurality of moveable support arms. The afterburner shroud is retractable. During operation of the afterburner shroud, the afterburner shroud is extended rearward toward the exhaust of the jet engine. A storage tank provides liquid oxygen through the support arms to a mixing ring located within the afterburner shroud. The mixing ring mixes the liquid oxygen and fuel to form a combustible mixture. The combustible mixture is injected into the exhaust wherein the mixture is ignited. The ignited mixture provides additional thrust for the jet engine.

8 citations


Journal Article
TL;DR: In this paper, a simulation of reacting flows in an aero-engine afterburner is performed using computational fluid dynamics (CFD) for calculating the three-dimensional reacting flow fields in a gas turbine after- burner.
Abstract: In this paper, reacting flows in an aero-engine afterburner are analyzed using computational fluid dynamics (CFD). A computationalprocedure is described for calculating the three-dimensional reacting flow fields in a gas turbine after- burner.The computations are based on numerical solution of time-averaged transport equations for mass, momentum, tur- bulentkinetic energy and dissipation rate using a finite volume formulation. The numerical calculations are performed using SIMPLE(Semi Implicit Method for Pressure Linked Equations). The RNG (Re-normalization Group Theory) k-s model is usedfor turbulence modeling. Combustion is modeled using PDF (Probability Density Function). The results for air-fuel ratioof 30 and 46 are obtained and analyzed. he amplitude an 'ace and helps i nship between, urface roughnes" In aircraft applications, larger thrust for a small dura- tion is required sometimes. This can be achieved in two ways. One way is to increase the mass flow rate. 'E Magazine MarchiThe other way is to add energy by burning additional , fuel in the tail pipe between turbine exhaust and the -387. entrance section of the exhaust nozzles. This way of

7 citations


Patent
18 Aug 2004
TL;DR: In this paper, a force-controlled throttle for adjusting the engine thrust of a combat aircraft with a handle for operation by a pilot and with a signal generating device that is connected to the handle for generating a control signal used for adjusting engine thrust.
Abstract: A force-controlled throttle for adjusting the engine thrust of a combat aircraft with a handle for operation by a pilot and with a signal generating device that is connected to the handle for generating a control signal used for adjusting the engine thrust. The signal generating device is provided for generating the control signal as a function of the force exerted by the pilot on the handle in operation. The throttle may include force-controlled elements for control of an afterburner.

4 citations


Patent
05 Feb 2004
TL;DR: In this paper, a swirl generator is used to convert oxidant flow into turbulent, three-dimensional flow field into which the fuel is introduced, and the generator is configured in a backward-flowing manner that carries heat and combustion byproducts upstream to continuously ignite a combustible fuel/oxidizer mixture in adjacent shear layers.
Abstract: PROBLEM TO BE SOLVED: To provide an afterburner apparatus that is relatively short and light, and has better fuel rate. SOLUTION: The afterburner apparatus utilizes a swirl generator for rapidly and efficiently atomizing, vaporizing, and mixing fuel into an oxidant. The swirl generator converts oxidant flow into turbulent, three-dimensional flow field into which the fuel is introduced. The swirl generator effects a toroidal outer recirculation zone and a central recirculation zone, which is positioned within the outer recirculation zone. These recirculation zones are configured in a backward-flowing manner that carries heat and combustion byproducts upstream where they are employed to continuously ignite a combustible fuel/oxidizer mixture in adjacent shear layers. The recirculation zones accelerate flame propagation to allow afterburning to be completed in a relatively short length. Inherent with this swirl afterburner concept are design compactness, light weight, lower cost, smooth and efficient combustion, high thrust output, wide flammability limits, continuous operation at stoichiometric fuel/oxidizer mixture ratios, no combustion instabilities, and relatively low pressure losses. COPYRIGHT: (C)2004,JPO&NCIPI

3 citations


Patent
17 Nov 2004
TL;DR: In this paper, the afterburner is formed as a surface burner and a heat exchanger warms up the air flow supplied to the fuel cell using the exhaust gas from the after-burner.
Abstract: The system includes a fuel cell (1), and an afterburner (6) for its exhaust gas, to which air is supplied as an oxidizing agent. A heat exchanger (9) warms up the air flow supplied to the fuel cell using the exhaust gas from the afterburner. A unit (23) containing the heat exchanger, a unit (22b) containing the afterburner, and a unit (21) containing the fuel cell are arranged one above the other to form a stack. The afterburner is formed as a surface burner.

3 citations


Patent
22 Sep 2004
TL;DR: In this paper, a method and system for clean burning organic or synthetic material, particularly vulcanized rubber, where fuel is ignited and the heat and smoke byproduct is maximized by controlling the amount of oxygen available to the fire.
Abstract: A method and system for clean burning organic or synthetic material, particularly vulcanized rubber, where fuel is ignited and the heat and smoke by-product is maximized by controlling the amount of oxygen available to the fire. The smoke by-product in an afterburner is reacted with steam, producing hydrogen and carbon monoxide, the products may be collected and stored. The extreme heat in the afterburner reduces the amount of pollutants and toxins in the air. Excess heat generated by burning the fuel may be used to power an engine.

2 citations


Patent
06 Feb 2004
TL;DR: In this paper, a swirl generator is used to convert an oxidant flow into a turbulent, three-dimensional flowfield into which the fuel is introduced, and the generator is configured in a backward-flowing manner that carries heat and combustion byproducts upstream to continuously ignite a combustible fuel/oxidizer mixture in adjacent shear layers.
Abstract: An afterburner apparatus (10) that utilizes a novel swirl generator (30) for rapidly and efficiently atomizing, vaporizing, as necessary, and mixing a fuel into an oxidant. The swirl generator (30) converts an oxidant flow into a turbulent, three-dimensional flowfield into which the fuel is introduced. The swirl generator (30) effects a toroidal outer recirculation zone (640) and a central recirculation zone (610), which is positioned within the outer recirculation zone. These recirculation zones are configured in a backward-flowing manner that carries heat and combustion byproducts upstream where they are employed to continuously ignite a combustible fuel/oxidizer mixture in adjacent shear layers. The recirculation zones accelerate flame propagation to allow afterburning to be completed in a relatively short length. Inherent with this swirl afterburner concept are design compactness, light weight, lower cost, smooth and efficient combustion, high thrust output, wide flammability limits, continuous operation at stoichiometric fuel/oxidizer mixture ratios, no combustion instabilities, and relatively low pressure losses.

2 citations


Patent
05 Feb 2004
TL;DR: In this article, an afterburning method for combustion ash and an afterburner device for efficiently processing the ash containing uncombusted portion in a fluidized bed combustion furnace was proposed.
Abstract: PROBLEM TO BE SOLVED: To provide an afterburning method for combustion ash and an afterburner device for efficiently processing the ash containing uncombusted portion in a fluidized bed combustion furnace. SOLUTION: The ash containing uncombusted portion produced through combustion in the fluidized bed combustion furnace A and gathered by a dust collecting machine 12 is supplied to a fine powder burning combustion furnace B, and the combustible component of the ash is burnt in a different burning environment. The fine powder burning combustion furnace B is furnished with a supplying means C for the ash containing uncombusted portion from the fluidized bed combustion furnace A. COPYRIGHT: (C)2004,JPO

1 citations


Patent
16 Jul 2004
TL;DR: In this article, the engine has an afterburner with an annular fuel injection ramp (34), and a spark plug mounted in the vicinity of the ramp, with a jet pipe for pulverization of fuel.
Abstract: The engine has an afterburner with an annular fuel injection ramp (34), and a spark plug (42) mounted in the vicinity of the ramp. The afterburner has an ignition injector (48) installed opposite to the plug and having a jet pipe for pulverization of fuel. The injector is connected to a conduit (49) that delivers fuel to the injector from a fuel source, under a controlled pressure independent of the supply conditions of the ramp.