Reduction of NO Emissions in a Turbojet Combustor by Direct Water
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
Failure Analysis of Gas Turbine Blades in a Gas Turbine Engine Used for Marine Applications
INTERNATIONAL JOURNAL OF International Journal of Engineering, Science and Technology MultiCraft ENGINEERING, Vol. 6, No. 1, 2014, pp. 43-48 SCIENCE AND TECHNOLOGY www.ijest-ng.com www.ajol.info/index.php/ijest © 2014 MultiCraft Limited. All rights reserved Failure analysis of gas turbine blades in a gas turbine engine used for marine applications V. Naga Bhushana Rao1*, I. N. Niranjan Kumar2, K. Bala Prasad3 1* Department of Marine Engineering, Andhra University College of Engineering, Visakhapatnam, INDIA 2 Department of Marine Engineering, Andhra University College of Engineering, Visakhapatnam, INDIA 3 Department of Marine Engineering, Andhra University College of Engineering, Visakhapatnam, INDIA *Corresponding Author: e-mail: [email protected] Tel +91-8985003487 Abstract High pressure temperature (HPT) turbine blade is the most important component of the gas turbine and failures in this turbine blade can have dramatic effect on the safety and performance of the gas turbine engine. This paper presents the failure analysis made on HPT turbine blades of 100 MW gas turbine used in marine applications. The gas turbine blade was made of Nickel based super alloys and was manufactured by investment casting method. The gas turbine blade under examination was operated at elevated temperatures in corrosive environmental attack such as oxidation, hot corrosion and sulphidation etc. The investigation on gas turbine blade included the activities like visual inspection, determination of material composition, microscopic examination and metallurgical analysis. Metallurgical examination reveals that there was no micro-structural damage due to blade operation at elevated temperatures. It indicates that the gas turbine was operated within the designed temperature conditions. It was observed that the blade might have suffered both corrosion (including HTHC & LTHC) and erosion. -
Progress and Challenges in Liquid Rocket Combustion Stability Modeling
Seventh International Conference on ICCFD7-3105 Computational Fluid Dynamics (ICCFD7), Big Island, Hawaii, July 9-13, 2012 Progress and Challenges in Liquid Rocket Combustion Stability Modeling V. Sankaran∗, M. Harvazinski∗∗, W. Anderson∗∗ and D. Talley∗ Corresponding author: [email protected] ∗ Air Force Research Laboratory, Edwards AFB, CA, USA ∗∗ Purdue University, West Lafayette, IN, USA Abstract: Progress and challenges in combustion stability modeling in rocket engines are con- sidered using a representative longitudinal mode combustor developed at Purdue University. The CVRC or Continuously Variable Resonance Chamber has a translating oxidizer post that can be used to tune the resonant modes in the chamber with the combustion response leading to self- excited high-amplitude pressure oscillations. The three-dimensional hybrid RANS-LES model is shown to be capable of accurately predicting the self-excited instabilities. The frequencies of the dominant rst longitudinal mode as well as the higher harmonics are well-predicted and their rel- ative amplitudes are also reasonably well-captured. Post-processing the data to obtain the spatial distribution of the Rayleigh index shows the existence of large regions of positive coupling be- tween the heat release and the pressure oscillations. Dierences in the Rayleigh index distribution between the fuel-rich and fuel-lean cases appears to correlate well with the observation that the fuel-rich case is more unstable than the fuel-lean case. Keywords: Combustion Instability, Liquid Rocket Engines, Reacting Flow. 1 Introduction Combustion stability presents a major challenge to the design and development of liquid rocket engines. Instabilities are usually the result of a coupling between the combustion dynamics and the acoustics in the combustion chamber. -
Water/Methanol Injection: Frequently Asked Questions
Water/Methanol Injection: Frequently Asked Questions Water/methanol injection is nothing new. It has been used as far back as World War II to help power German fighter planes. Yet it never seemed to catch on as a mainstream power adder in the hot rodding world—until recent years. Many companies are now offering easy to install water/methanol injections systems for affordable prices. Available for naturally aspirated or forced induction gasoline and diesel applications, these systems inject a roughly 50/50 mixture of methanol and water into the engine using a high-pressure pump. This magical mixture allows for more ignition timing, increases boost capability in supercharged or turbocharged applications, lowers air intake temperature, and provides an additional source of very high-octane fuel—all without increasing the chance of damaging detonation. Water injection systems are predominantly useful in forced induction (turbocharged or supercharged), internal combustion engines. Only in extreme cases such as very high compression ratios, very low octane fuel or too much ignition advance can it benefit a normally aspirated engine. The system has been around for a long time since it was already used in some World War II aircraft engines, which allowed them to produce more power and therefore fly at higher altitudes. A water injection system works similarly to a fuel injection system only it injects water instead of fuel. Water injection is not to be confused with water spraying on the intercooler's surface, water spraying is much less efficient and far less sophisticated. A turbocharger or supercharger essentially compresses the air going into the engine in order to force more air than would be possible with the atmospheric pressure. -
Dual-Mode Free-Jet Combustor
Dual-Mode Free-Jet Combustor Charles J. Trefny and Vance F. Dippold III [email protected] NASA Glenn Research Center Cleveland, Ohio USA Shaye Yungster Ohio Aerospace Institute Cleveland, Ohio USA ABSTRACT The dual-mode free-jet combustor concept is described. It was introduced in 2010 as a wide operating-range propulsion device using a novel supersonic free-jet combustion process. The unique feature of the free-jet combustor is supersonic combustion in an unconfined free-jet that traverses a larger subsonic combustion chamber to a variable throat area nozzle. During this mode of operation, the propulsive stream is not in contact with the combustor walls and equilibrates to the combustion chamber pressure. To a first order, thermodynamic efficiency is similar to that of a traditional scramjet under the assumption of constant-pressure combustion. Qualitatively, a number of possible benefits to this approach are as follows. The need for fuel staging is eliminated since the cross-sectional area distribution required for supersonic combustion is accommodated aerodynamically without regard for wall pressure gradients and boundary-layer separation. The unconstrained nature of the free-jet allows for consideration of a detonative combustion process that is untenable in a walled combustor. Heat loads, especially localized effects of shock wave / boundary-layer interactions, are reduced making possible the use of hydrocarbon fuels to higher flight Mach numbers. The initial motivation for this scheme however, was that the combustion chamber could be used for robust, subsonic combustion at low flight Mach numbers. At the desired flight condition, transition to free-jet mode would be effected by increasing the nozzle throat area and inducing separation at the diffuser inlet. -
A Comparison of Combustor-Noise Models – AIAA 2012-2087
A Comparison of Combustor-Noise Models – AIAA 2012-2087 Lennart S. Hultgren, NASA Glenn Research Center, Cleveland, OH 44135 Summary The present status of combustor-noise prediction in the NASA Aircraft Noise Prediction Program (ANOPP)1 for current- generation (N) turbofan engines is summarized. Several semi-empirical models for turbofan combustor noise are discussed, including best methods for near-term updates to ANOPP. An alternate turbine-transmission factor2 will appear as a user selectable option in the combustor-noise module GECOR in the next release. The three-spectrum model proposed by Stone et al.3 for GE turbofan-engine combustor noise is discussed and compared with ANOPP predictions for several relevant cases. Based on the results presented herein and in their report,3 it is recommended that the application of this fully empirical combustor-noise prediction method be limited to situations involving only General-Electric turbofan engines. Long-term needs and challenges for the N+1 through N+3 time frame are discussed. Because the impact of other propulsion-noise sources continues to be reduced due to turbofan design trends, advances in noise-mitigation techniques, and expected aircraft configuration changes, the relative importance of core noise is expected to greatly increase in the future. The noise-source structure in the combustor, including the indirect one, and the effects of the propagation path through the engine and exhaust nozzle need to be better understood. In particular, the acoustic consequences of the expected trends toward smaller, highly efficient gas- generator cores and low-emission fuel-flexible combustors need to be fully investigated since future designs are quite likely to fall outside of the parameter space of existing (semi-empirical) prediction tools. -
Comparison of Helicopter Turboshaft Engines
Comparison of Helicopter Turboshaft Engines John Schenderlein1, and Tyler Clayton2 University of Colorado, Boulder, CO, 80304 Although they garnish less attention than their flashy jet cousins, turboshaft engines hold a specialized niche in the aviation industry. Built to be compact, efficient, and powerful, turboshafts have made modern helicopters and the feats they accomplish possible. First implemented in the 1950s, turboshaft geometry has gone largely unchanged, but advances in materials and axial flow technology have continued to drive higher power and efficiency from today's turboshafts. Similarly to the turbojet and fan industry, there are only a handful of big players in the market. The usual suspects - Pratt & Whitney, General Electric, and Rolls-Royce - have taken over most of the industry, but lesser known companies like Lycoming and Turbomeca still hold a footing in the Turboshaft world. Nomenclature shp = Shaft Horsepower SFC = Specific Fuel Consumption FPT = Free Power Turbine HPT = High Power Turbine Introduction & Background Turboshaft engines are very similar to a turboprop engine; in fact many turboshaft engines were created by modifying existing turboprop engines to fit the needs of the rotorcraft they propel. The most common use of turboshaft engines is in scenarios where high power and reliability are required within a small envelope of requirements for size and weight. Most helicopter, marine, and auxiliary power units applications take advantage of turboshaft configurations. In fact, the turboshaft plays a workhorse role in the aviation industry as much as it is does for industrial power generation. While conventional turbine jet propulsion is achieved through thrust generated by a hot and fast exhaust stream, turboshaft engines creates shaft power that drives one or more rotors on the vehicle. -
Water Injection on Commercial Aircraft to Reduce Airport Nitrogen Oxides
NASA/TM—2010-213179 Water Injection on Commercial Aircraft to Reduce Airport Nitrogen Oxides David L. Daggett and Lars Fucke Boeing Commercial Airplane, Seattle, Washington Robert C. Hendricks Glenn Research Center, Cleveland, Ohio David J.H. Eames Rolls-Royce Corporation, Indianapolis, Indiana March 2010 NASA STI Program . in Profile Since its founding, NASA has been dedicated to the • CONFERENCE PUBLICATION. Collected advancement of aeronautics and space science. The papers from scientific and technical NASA Scientific and Technical Information (STI) conferences, symposia, seminars, or other program plays a key part in helping NASA maintain meetings sponsored or cosponsored by NASA. this important role. • SPECIAL PUBLICATION. Scientific, The NASA STI Program operates under the auspices technical, or historical information from of the Agency Chief Information Officer. It collects, NASA programs, projects, and missions, often organizes, provides for archiving, and disseminates concerned with subjects having substantial NASA’s STI. The NASA STI program provides access public interest. to the NASA Aeronautics and Space Database and its public interface, the NASA Technical Reports • TECHNICAL TRANSLATION. English- Server, thus providing one of the largest collections language translations of foreign scientific and of aeronautical and space science STI in the world. technical material pertinent to NASA’s mission. Results are published in both non-NASA channels and by NASA in the NASA STI Report Series, which Specialized services also include creating custom includes the following report types: thesauri, building customized databases, organizing and publishing research results. TECHNICAL PUBLICATION. Reports of completed research or a major significant phase For more information about the NASA STI of research that present the results of NASA program, see the following: programs and include extensive data or theoretical analysis. -
2. Afterburners
2. AFTERBURNERS 2.1 Introduction The simple gas turbine cycle can be designed to have good performance characteristics at a particular operating or design point. However, a particu lar engine does not have the capability of producing a good performance for large ranges of thrust, an inflexibility that can lead to problems when the flight program for a particular vehicle is considered. For example, many airplanes require a larger thrust during takeoff and acceleration than they do at a cruise condition. Thus, if the engine is sized for takeoff and has its design point at this condition, the engine will be too large at cruise. The vehicle performance will be penalized at cruise for the poor off-design point operation of the engine components and for the larger weight of the engine. Similar problems arise when supersonic cruise vehicles are considered. The afterburning gas turbine cycle was an early attempt to avoid some of these problems. Afterburners or augmentation devices were first added to aircraft gas turbine engines to increase their thrust during takeoff or brief periods of acceleration and supersonic flight. The devices make use of the fact that, in a gas turbine engine, the maximum gas temperature at the turbine inlet is limited by structural considerations to values less than half the adiabatic flame temperature at the stoichiometric fuel-air ratio. As a result, the gas leaving the turbine contains most of its original concentration of oxygen. This oxygen can be burned with additional fuel in a secondary combustion chamber located downstream of the turbine where temperature constraints are relaxed. -
Helicopter Turboshafts
Helicopter Turboshafts Luke Stuyvenberg University of Colorado at Boulder Department of Aerospace Engineering The application of gas turbine engines in helicopters is discussed. The work- ings of turboshafts and the history of their use in helicopters is briefly described. Ideal cycle analyses of the Boeing 502-14 and of the General Electric T64 turboshaft engine are performed. I. Introduction to Turboshafts Turboshafts are an adaptation of gas turbine technology in which the principle output is shaft power from the expansion of hot gas through the turbine, rather than thrust from the exhaust of these gases. They have found a wide variety of applications ranging from air compression to auxiliary power generation to racing boat propulsion and more. This paper, however, will focus primarily on the application of turboshaft technology to providing main power for helicopters, to achieve extended vertical flight. II. Relationship to Turbojets As a variation of the gas turbine, turboshafts are very similar to turbojets. The operating principle is identical: atmospheric gases are ingested at the inlet, compressed, mixed with fuel and combusted, then expanded through a turbine which powers the compressor. There are two key diferences which separate turboshafts from turbojets, however. Figure 1. Basic Turboshaft Operation Note the absence of a mechanical connection between the HPT and LPT. An ideal turboshaft extracts with the HPT only the power necessary to turn the compressor, and with the LPT all remaining power from the expansion process. 1 of 10 American Institute of Aeronautics and Astronautics A. Emphasis on Shaft Power Unlike turbojets, the primary purpose of which is to produce thrust from the expanded gases, turboshafts are intended to extract shaft horsepower (shp). -
Direct Injection of Water Mist in an Intake Manifold Spark Ignition Engine
International Journal of Automotive and Mechanical Engineering (IJAME) ISSN: 2229-8649 (Print); ISSN: 2180-1606 (Online); Volume 12, pp. 2809-2819, July-December 2015 ©Universiti Malaysia Pahang DOI: http://dx.doi.org/10.15282/ijame.12.2015.1.0236 Direct injection of water mist in an intake manifold spark ignition engine A.R. Babu1*, G. Amba Prasad Rao1 and T. Hari Prasad2 1Department of Mechanical Engineering, NIT, Warangal, 506004, India *Email: [email protected] Phone: +919581993346; Fax: +918572245126 2Department of Mechanical Engineering, SVEC, Tirupati, 5171024, India ABSTRACT The purpose of this study is to investigate the effects of water mist (WM) injected directly into an intake manifold spark ignition (SI) engine. WM flows through a nozzle at the throttle body of the four-cylinder four-stroke multi-point injection engine for testing the performance of exhaust emission system. The water is pumped in mist form into the intake manifold with an air-fuel mixture through the nozzle, which is located on the throttle body. Experimental work and simulation methods are combined by the presence and absence of WM addition, and the performance as well as emission produced by the engine is analyzed. The Gamma Technologies (GT) methods are used to simulate the model with and without WM addition. The experimental results indicate that the standard engine performance can be used to validate the simulation model. The engine measures include various parameters such as brake power, torque, volumetric efficiency, spark advance timing, and the concentration of CO and NOx with water and without water addition to the SI engine (i.e., the power, torque, volumetric efficiency of the engine is increased up to 10%). -
The Power for Flight: NASA's Contributions To
The Power Power The forFlight NASA’s Contributions to Aircraft Propulsion for for Flight Jeremy R. Kinney ThePower for NASA’s Contributions to Aircraft Propulsion Flight Jeremy R. Kinney Library of Congress Cataloging-in-Publication Data Names: Kinney, Jeremy R., author. Title: The power for flight : NASA’s contributions to aircraft propulsion / Jeremy R. Kinney. Description: Washington, DC : National Aeronautics and Space Administration, [2017] | Includes bibliographical references and index. Identifiers: LCCN 2017027182 (print) | LCCN 2017028761 (ebook) | ISBN 9781626830387 (Epub) | ISBN 9781626830370 (hardcover) ) | ISBN 9781626830394 (softcover) Subjects: LCSH: United States. National Aeronautics and Space Administration– Research–History. | Airplanes–Jet propulsion–Research–United States– History. | Airplanes–Motors–Research–United States–History. Classification: LCC TL521.312 (ebook) | LCC TL521.312 .K47 2017 (print) | DDC 629.134/35072073–dc23 LC record available at https://lccn.loc.gov/2017027182 Copyright © 2017 by the National Aeronautics and Space Administration. The opinions expressed in this volume are those of the authors and do not necessarily reflect the official positions of the United States Government or of the National Aeronautics and Space Administration. This publication is available as a free download at http://www.nasa.gov/ebooks National Aeronautics and Space Administration Washington, DC Table of Contents Dedication v Acknowledgments vi Foreword vii Chapter 1: The NACA and Aircraft Propulsion, 1915–1958.................................1 Chapter 2: NASA Gets to Work, 1958–1975 ..................................................... 49 Chapter 3: The Shift Toward Commercial Aviation, 1966–1975 ...................... 73 Chapter 4: The Quest for Propulsive Efficiency, 1976–1989 ......................... 103 Chapter 5: Propulsion Control Enters the Computer Era, 1976–1998 ........... 139 Chapter 6: Transiting to a New Century, 1990–2008 .................................... -
Fuel Injection and Anti-Detonation
Fuel Injection • These systems are similar to the Bendix/Stromberg pressure carburetors. • Air / fuel metering is accomplished by one device, fuel distribution occurs by intake distribution pipes. Unliscensed copyrighted material - W. North 1998 Fuel Injection • Manufacturers – Bendix – Contentintal Unliscensed copyrighted material - W. North 1998 Fuel Injection • Bendix • RS and RSA systems • Has four main sections – Air metering and regulation – fuel regulation – fuel metering – fuelUnliscensed distribution copyrighted material - W. North 1998 Fuel Injection • Uses the same A, B, C, D, pressures A = Impact air pressure B = Venturi air pressure C = Metered fuel pressure D = Fuel inlet pressure and Flow divider discharge pressure Unliscensed copyrighted material - W. North 1998 Fuel Injection • Air metering and regulation – accomplished by throttle plate and a throttle body assembly. – impact air and venturi air pressures are sourced here. – automatic mixture control valve regulates pressure value of impact air with venturi air. Unliscensed copyrighted material - W. North 1998 Fuel Injection • Fuel regulation – diaphragms and poppet valve attached to throttle assembly. – fuel inlet pressure closes poppet valve – metered fuel pressure and A - B pressure differential open poppet. Unliscensed copyrighted material - W. North 1998 Fuel Injection – balancing springs alter diaphragm values for low airflow idle conditions. – springs assist poppet valve to open for idle fuel delivery. – idle rotary valve is linked to throttle valve. Unliscensed copyrighted material - W. North 1998 Fuel Injection • Fuel metering section includes: – 74 micron finger screen – idle/enrichment fuel control rotary valve. – main and enrichment metering jets. – manual mixture and idle cut off rotary valve. Unliscensed copyrighted material - W. North 1998 Fuel Injection • Fuel distribution – metered fuel passes the poppet valve into plumbing to the flow divider where it forces open the pressurizing valve.