Showing papers on "Afterburner published in 2003"

Compact swirl augmented afterburners for gas turbine engines

Abstract: An afterburner apparatus that utilizes a novel swirl generator for rapidly and efficiently atomizing, vaporizing, as necessary, and mixing a fuel into an oxidant. The swirl generator converts an oxidant flow into a turbulent, three-dimensional flowfield 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.

Emissions of batch combustion of waste tire chips: the afterburner effect

Abstract: A laboratory investigation was performed on the emissions from batch combustion of waste tire chips in fixed beds to identify techniques and conditions that minimize toxic emissions Tire derived fuel (TDF), in the form of waste tire chips (1 cm), was burned in a two-stage combustor Batches of tire chips were introduced to the primary furnace where gasification and oxidative pyrolysis took place The gaseous effluent of this furnace was mixed with streams of additional air and, subsequently, it was channeled into the secondary furnace (afterburner) where further oxidation took place The arrangement of two furnaces in series allows for independent temperature control; varying the temperature in the primary furnace influences the type and the flux of pyrolysates The additional-air mixing section between the two furnaces allows for mostly heterogeneous and fuel-lean combustion in the afterburner Results showed that both the operating temperature of the primary furnace, in the range of 500-1000 °C, and the existence of the afterburner had marked influences on the emissions of pollutants Results showed that for this fuel use of combustion staging, with an additional-air mixing section, had a very beneficial effect It drastically reduced the emissions of CO (by factors of 3-10), the particulates (by factors of 2-5) and the cumulative PAH (by factors of 2-3) Many health-hazardous PAH components were practically eliminated Overall oxidizing conditions prevailed and the minimum oxygen mole fraction never fell below 2% in the effluent of either furnace The operating primary furnace temperature (pyrolysis temperature) also proved to be important, with temperatures at the low side of the 500-1000 °C range producing fewer pollutants, upon treatment in the afterburner

Exhaust gas recirculation afterburner

Abstract: An embodiment of the invention includes an exhaust gas recirculation (EGR) valve, an intake pipe, and an afterburner. As the intake valve communicates an exhaust gas stream to an EGR valve, an afterburner affixed to an inside wall of the intake pipe captures and burns large particles contained in the exhaust gas stream to prevent obstruction of the EGR valve.

Validation of a Mixed Flow Turbofan Performance Model in the Sub-Idle Operating Range

Abstract: During turbofan development programs the evaluation of steady-state and transient engine performance is usually achieved by applying full thermodynamic engine models at least in the operating range between idle and maximum power conditions, but more recently also in the sub-idle operating range, e.g. for steady-state windmilling behavior and for starting, relight and shut down scenarios. The paper describes the setup, and in more detail the validation, of a full thermodynamic engine model for a two-spool mixed flow afterburner turbofan which is capable to run from maximum power down to zero speed and zero flow conditions in steady-state and transient mode. The validation is performed by using the model-based performance analysis procedure called ANSYN even in windmilling operation. Once the steady-state sub-idle model is validated the extension to transient sub-idle capability is achieved by simply adding the effects of rotor moment of inertia of the spools, while heat soakage effects are rather negligible without heat release in the burner. Especially lighting conditions in the burner are produced by such a validated sub-idle model inherently due to reliable data calculated at the burner entry station. The variety of applications of a validated full thermodynamic engine model is large. The performance data delivered is highly reliable and very consistent because the full operating range of the engine is covered with one model, and by appropriate means of speeding up the calculation even real-time capability may be achieved. In the paper synthesized data for an engine dry crank is compared to real engine test data as one typical application.Copyright © 2003 by ASME

Thermodynamic Modeling and Performance Analysis of a Power Generation System Based on the Solid Oxide Fuel Cell

Abstract: Performance analysis with detailed thermodynamic models of a power generation system based on the solid oxide fuel cell (SOFC) is presented. The proposed power system in this study is composed of an external reformer, a SOFC with an internal reformer, an afterburner, and preheaters. Natural gas (CH4 ) as supplied fuel to the SOFC is reformed to hydrogen (H2 ) by external and internal reformers. Necessary steam for the use in reformers is either externally supplied or internally recirculated from exit of the SOFC. Exhaust gas of the SOFC containing steam and other chemical compositions is combusted in afterburner to raise its temperature to preheat supplied fuel and air. It is found from the results of performance analysis that the system performance can be enhanced by the use of internally recirculated steam from the exhaust gas of the SOFC. It is also found that the benefit of the high-pressure operation is not so secure if the power to compress supplied air is consumed from the produced power of the system. Installation of a turbine at the system exhaust produces necessary power to pressurize supplied air and, additionally, extra power to enhance total power density of the system.Copyright © 2003 by ASME

Post-combustion device

Abstract: An afterburner, in particular for chemical reformers intended to procure hydrogen, for afterburning residual gases from a reforming and/or fuel cell process has at least one nozzle for metering fuel and combustible residual gases into a combustion chamber and at least one air supply. The combustion chamber is at least partially filled with a heat-resistant, open-pore ceramic foam.

Analysis of non-reacting flow in an aircraft gas turbine engine afterburner model using finite volume method

Abstract: This paper focuses on the aerodynamics of the non-reacting flow inside an aero-gas turbine engine afterburner by carrying out a three-dimensional CFD analysis using the finite volume approach. A 60° sector of the afterburner with all the complexities has been modelled to take advantage of the symmetry of the design. The computational methodology employed SIMPLE algorithm for pressure velocity coupling, RNG k-E model for turbulence in an unstructured and non­ uniform grid. The analysis has been carried out for sea level inlet conditions. A recirculation zone was seen to be formed behind the V -gutters and inner wall of the diffuser. The performance of the diffuser was found to be good and the Mach number just upstream of the V -gutter was found to be in line with requirements. The pressure loss was in line with successful designs and the nozzle performance was found to be satisfactory . The predicted flow fields are verified using exi sting experimental results . The results for various mass flow rates and different geometries are presented for the closed nozzle position. Military turbojets require greater thrust during take off and high speed 'dogfight' manoeuvers. Various methods of thrust augmentation exist and the principle is to either increase the mass flow rate (by injection of water, water alcohol mixture or refrigerants) , or increase the energy (by burning fuel in the turbine exhaust or air bled from compressor). The constraining factor being space and weight, as also the cost, the afterburner has become the universal choice for military turbojets. It fits into the tailpipe region and has the most favourable thrust to weight ratio. But the afterburner also entails some penalty in the form of pressure losses (cold loss) when it is not in use as also the 'hot losses' when in use. The components required for achieving the design intent in an afterburner also cause unavoidable pressure losses in the turbojet. A diffuser is provided at the turbine exit in order to decelerate the flow so as to allow combustion to initiate . Flame stabilizer is provided in order to ensure that proper combustion takes place and blowout of flame does not take place. The fuel manifolds are provided to supply the fuel into the combustion chamber. Supporting structures al so cause obstruction in the flow and cause pressure losses.

Method of operation of triple-flow aircraft turbojet engine and design of said engine

Abstract: FIELD: aero-engine manufacturing; supersonic turbojet engines. SUBSTANCE: in process of operation of proposed aircraft turbojet engine, air is delivered into outer direct flow and inner loops of engine, air is compressed in sections of main compressor and fuel is combusted in compressed air in combustion chamber and combustion products, thus formed, are expanded in turbine and propulsive jet nozzle. Combustion products are divided at combustion chamber outlet into two flows, one of which is directed to direct flow loop. Other flow is mixed with part of air from cooling loop and is directed to turbine input. Combustion products outflowing from propulsive jet nozzle of direct flow loop at supersonic speed are directed into mixing chamber to eject expanded combustion products getting of turbine. At afterburner power, temperature in combustion chamber is decreased to braking temperature, and delivery of cooling air to turbine input is decreased owing to bypassing to provide mixing of cooling air with combustion products getting into direct flow loop. In process of operation of the ground and at low altitudes air is delivered into engine inner loop from direct flow loop to input of main compressor. At increase of aircraft flight altitude higher than4000 m, air delivery into direct flow loop is cut off, and delivery of air to input of main compressor is provided through section of low-pressure additional compressor by successively connecting its stages, starting from last one, and finishing by first one at attaining designed altitude of flight. At increase of aircraft flight speed higher than supersonic speed, compressor stages are successively disconnected starting from section of low-pressure additional compressor to last stage of main compressor, and direct flow loop is cut in. Simultaneously operation of sections of compressors and turbine is coordinated owing to adjusting of propulsive jet nozzle and changing of mixing chamber passage area. Invention makes it possible to increase thrust at minimum consumption of fuel at increase of flight altitude, air single shaft engine is used, owing to preservation of constant second air consumption at all flight conditions. EFFECT: increased thrust. 7 cl, 1 dwg

Afterburner device and method for operating an afterburner device

Abstract: An afterburner device and a method for operating an afterburner device, especially for chemical reformers for obtaining hydrogen, for making heat available from fuels and/or residual gases from a reforming process and/or a fuel cell process. In this context, heat is supplied in a controlled manner from recirculated combustion gases to a first housing and/or a combustion chamber situated in it and at least in part filled with heat resistant, open-pored foamed ceramics. The regulation takes place, for instance, based on a temperature recorded in the combustion chamber using an infrared light measurement.

Improvement of the performance of a turbo-ramjet engine for UAV and missile applications

Abstract: : An existing turbo-ramjet engine was modified in order to increase the produced thrust and sustain combustion at increased freejet Mach numbers. The engine's afterburner fuel system was redesigned to improve the vaporization and atomization of the fuel. The engine performed satisfactorily at speeds up to Mach 0.3, producing 100% more thrust over the baseline turbojet. The data acquisition system of the turbo-ramjet engine's performance measurement in a freejet facility was also updated. Various Computational Fluid Dynamics models of the flow through the turbo-ramjet engine were developed to visualize the flow and to predict the engine performance at different Mach numbers.

Cyclone-type furnace extension

Abstract: FIELD: combustion of wood biomass recovery waste. SUBSTANCE: furnace extension has cyclone chamber, afterburner for large fractions of fuel, fire grate, tangential nozzles, and outlet branch pipe. Afterburner is mounted under cyclone chamber, both being separated by means of knuckle with shoulder; conical fire grate is mounted in afterburner and outlet branch pipe is disposed on side surface of the latter. Proposed furnace extension is distinguished by an extended range of effective combustion of wood waste whose moisture content is as high as 60-65%. EFFECT: enhanced completeness of fuel combustion, reduced emission of nitrogen oxides. 3 dwg

Design and Testing of a Combustor for a Turbo-Ramjet Engine for UAV and Missile Applications

Abstract: : An existing freejet facility was upgraded and its range of operation extended into the high subsonic regime for operation as a test rig for the development of a combined-cycle turbo-ramjet engine A combustor was designed developed and tested as the afterburner for the turbo-ramjet engine At subsonic speeds with the afterburner running an increase in thrust of 40% was measured over the baseline turbojet running at 80% spool speed A Computational Fluid Dynamics model of the flow through the shrouded turbojet engine was developed and successfully used to assist in predicting the bypass ratio of the engine at different Mach numbers Numerous recommendations were made to improve the operation of the test rig to improve the performance of the turbo-ramjet engine and refine the numerical models These recommended improvements will extend the present capabilities to design and analyze small combined cycle engines which have an application in unmanned aerial vehicles and missiles

Fuel cell system especially for an electric vehicle has air supply to exhaust gas after burner that conducts part of anode exhaust gas to the burner

Abstract: A fuel cell system, especially for an electric vehicle, comprises fuel cells (5) with cathode and anode exhaust gas streams, a reformer (14) and an exhaust gas after burner (18) with air supply device (19) At least part of the anode exhaust gas stream is led to the afterburner by the air supply that is connected to the fuel cells. An independent claim is also included for an operating process for the above.