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Two-Stage Combustor Design for Low Emission

Most of the man-made emissions are generated on the earth’s surface and emitted into the atmospheric boundary layer  up to about one kilometer. A large fraction of these pollutants return to the surface through wet or dry deposition.  However, some penetrate  beyond  into the free troposphere and further depending on their atmospheric residence time.  Aircrafts are the only high altitude man-made source of emissions. The effect of NO_x on ozone creation or depletion is highly altitude dependent.  Subsonic airplanes cruise at altitudes of 8-13 km whereas supersonic ones cruise at higher altitudes of around 20 km.  The NO_x emissions from subsonic aircrafts are considered to produce ozone, which is a  strong greenhouse gas. However, the concern over environmental impact of aircrafts is not just due to the point of release of the emissions but also the  projected rapid growth of the aviation industry. The uniqueness of the aircraft engine emission comes from the following factors.  First, air traffic growth exceeds ground traffic growth rate. Second, pollutants of air traffic are emitted at high altitudes where they have a greater influence than those at the ground level. Third, increasing engine operating conditions (higher combustion chamber pressure and combustor inlet temperature) of modern highly-efficient gas turbine engine designs tend to increase the quantity of  NO_x per unit of fuel consumed.   

Aircraft engines are regulated on the amount of pollutants they produce. The International Civil Aviation Organization (ICAO) sets the standards. The species that are regulated are NO_x, CO, unburned hydrocarbon, and smoke. The increasingly stringent emission regulations remain the major driving force for civil aircraft gas turbine combustion research. While the best annular combustor technology is able to meet current regulations, the double annular combustors (DAC) have demonstrated a substantial reduction in NOx production. These low pollutant engines (already in service) are the starting point for ultra low emission combustors. A solid understanding of the mechanism of pollutants formations in the combustion chamber along with thorough knowledge of fuel combustion and design issues in gas turbine combustors are the main objectives of this seminar.

This seminar starts with a concise yet effective review of the combustion issues and terminology in engines to establish a uniform knowledge base. This requires sufficient knowledge on fuels, in particular, unique requirements of aviation fuels, and air quality at different altitudes. Fundamentals of combustion thermodynamics are effectively discussed next. Concepts such as equilibrium, adiabatic temperature, and heating values are explained. Then the focus is turned on the combustion chemistry in which topics such as reaction rate, autoignition, and reaction mechanisms are discussed. Flame propagation, stabilization, and quenching are covered next followed by some basic knowledge on liquid fuel drop evaporation and burning issues. Stirred reactor concept and efficiencies (combustion, thermal, propulsion) are adequately discussed with some examples. Detailed discussion of combustion, pollutant formation mechanisms, liquid fuel atomization and their complex interactions are presented next. Ignition issues such as altitude relight are sufficiently covered. A simple design problem is presented to describe the methodology. Near-term and long-term trends in combustor designs and their rational are fully presented towards the end of the seminar.

Individuals interested in this seminar should contact Advanced Technology Consultants (ATC) directly. Due to ATC's low overhead, direct-contact clients are offered a competitive and cost-effective package. Alternatively, these seminars are also sponsored by American Institute of Aeronautics and Astronautics (AIAA) (page 27) and Society of Automotive Engineers organizations. Also, look at page 28 of the AIAA Professional Development Catalog.

 

 

 

 

 

 

 

 

Electronic and hard copies of the seminar materials can be purchased and are only available through ATC. Contact ATC for price and shipping.

 

NOTE: Professionally-prepared "audio-video Powerpoint-type presentations" of these seminars are available for purchase by the companies. Each slide is presented with a clear audio by the consultant, describing the subject, while a digital pointer guides the audience to where the attention is to be focused. Companies can put such audio-video presentations on their intranet to be used by their employees. It is a cost effective way approaching  professional training which also contributes towards R&D, design, and intelligent new product development. Presentations are updated every year at a fraction of the original cost.  For a sample presentation click on the word "IGNITION" in the picture (High-speed internet access is recommended) to get a feel of how information is transferred. The actual copy sold is of high resolution with high quality sound. For more details and pricing please contact ATC.

 

 

 

 

 

Benefits of Attending

·        Upon completion of this seminar, you will:

·        Gain a comprehensive understanding of the important processes in gas turbine engine combustor and its relation to engine performance, efficiency, and emission

·        Receive a concise yet effective overview of the combustion in combustion engine

·        Develop the background and necessary foundation to educate yourself beyond the depth and topics covered

·        Learn strategies for reduction of pollutant species from gas turbine engines

·        Understand the effects of combustor design and engine operating conditions on combustion and emission

·        Be able to communicate effectively with engineers working on ignition, combustion, and emission aspects in your company

·        Grasp the technology and the logic behind the current and future engine combustor designs

·        Effectively contribute to the design of critical components such as compressor, combustion chamber, turbine, and exhaust systems

·        Identify key factors for optimum combustion chamber design and low engine emission of pollutants.

Who Should Attend

This seminar will be especially valuable for engineers, technical and project managers, researchers, and academicians involved in combustion/emission aspects of the gas turbine engines. Currently, the design of many components in these engines are affected by combustion and emission control measures to meet customer’s, federal, and international demands and regulations. Therefore, engineers working on the design of components for high efficiency and performance of these combustion engines as well as those directly and indirectly involved in ignition and emission reduction strategies will highly benefit from this seminar. Additionally, this seminar provides adequate background for engineers and managers in contact with those directly involved in ignition, combustion, and emission issues and will prepare them for a more efficient and intelligent communication style in an interdisciplinary environment. Engineers desiring to expand their understanding of combustion and fluid/heat transfer processes and their impact on performance and emissions from the engines will highly benefit by attending this seminar.

How to Arrange for a Presentation:
 

Due to ATC's low overhead, direct-contact clients are offered a  competitive and cost-effective package.  Individuals interested in these seminars should contact Advanced Technology Consultants (ATC) directly.

 

Table of Contents

Day one

Fuel

Pure hydrocarbon fuels

Overview of petroleum refining process

Gas turbine fuels (0-GT, 1-GT, 2-GT, 3-GT, 4-GT)

Civil & military aviation fuels (JET A-1, JET A, JET B; JP-4, JP-5, JP-8)

Role of fuel additives stability, distillation range, vapor pressure, volatility, flash point, freezing point, autoignition temperature, etc.

Air

Combustion thermodynamics 

Stoichiometry

First law (energy equation)

Adiabatic temperature and heating value

Thermodynamic equilibrium

Combustion chemistry

Reaction rate (Arrenhenius equation)

Autoignition and generalized kinetic model

Hydrogen-oxygen reaction mechanism

Hydrocarbon reaction mechanism

Day two 

Flame

Laminar burning speed (S_L)

Effects of some key parameters on (S_L )

Flame quenching

Flame stabilization mechanism (flash back and blow off)

A movie of combustion and flame stabilization in a swirl-stabilized combustor

Droplet evaporation and flame burning

Stirred reactor theory

Combustion efficiency

Basic concept

Effects of primary and secondary zones

Applications

Thermal and propulsion efficiencies

Combustion in gas turbine engines

Combustion chamber requirements

Sources of pollutants

Emission standards

Landing and takeoff (LTO) cycle

Typical emission results

Effects of turbine inlet and overall pressure ratio on sfc

 

Primary, intermediate and dilution zones

Health and environmental impacts of different pollutants

Different combustor designs

Evolutionary history of combustor geometry

Key processes and their time scales

Introduction to liquid fuel atomization and fuel nozzle designs

Nitric oxides formation mechanisms (Zeldovich and others)

CO formation mechanism

HC and smoke formation mechanisms

Flame holding and stabilization inside the combustor

Fuel and air staging

Exhaust emission measurements and their relationship to combustor processes

Detailed combustor flow and species measurements and interpretations 

Day three 

Ignition

Ignition system and performance

Ignition energy, spark duration and rate

Igniter location

Ignition theory

Homogeneous

Heterogeneous (liquid spray ignition)

Effects of design and operating conditions on minimum ignition energy

Ignition performance

Ignition system

Flow variables

Fuel parameters

Ignition/relight envelope and measures to improve relight

Alternative ignition strategies

An example of a simple design methodology

Effects of variations in equivalence ratio  (φ)

Mixedness parameter effects

Performance requirement & design variables

Pressure loss factor

Combustor loading parameter

Primary zone equivalence ratio  (φ_pz)

Fuel nozzle performance factors

Combustion zone length (or volume)

Dilution zone length (or volume)

Ignition parameters

Combustion efficiency

Others

Near-term and long-term trends in combustor design

Minor changes to liner and/or fuel nozzle designs

Minor changes in combustor airflow pattern and location of injector

Improvements in engine turbomachinery

Major changes to liner and/or fuel nozzle designs

Staged combustion

Lean premixed prevaporization (LPP)

Rich- quench-lean (RQL) design

Catalytic combustion

Hot wall and recuperative cooling combustors

Advanced topics

Combustion instability

Health monitoring

Others (topics vary based on current research)

Summary and conclusions

Instructor: Bruce Chehroudi

Instructor:  Bruce Chehroudi  

Dr. Chehroudi, has accumulated years of technical and leadership experiences in different capacities and organizations. This includes such positions as a Principal Scientist and Group Leader appointment at the Air Force Research Laboratory (AFRL) ERCInc, a Chief Scientist at Raytheon STX, a Visiting Technologist at Ford’s Advanced Manufacturing Technology Development (AMTD) center, a tenured Professor of Mechanical Engineering at Kettering University and University of Illinois, and served as a Senior Research Staff/Research Fellowship at Princeton University. Dr. Chehroudi directed numerous multimillion dollar interdisciplinary projects in areas involving chemically reacting flows, combustion and emission of pollutants, sustainable and alternative energy sources, distributed ignition, material/fuel injection, advanced pollution reduction technologies, propulsion concepts, gas turbine and liquid rocket engines, combustion instability, laser optical diagnostics, spectroscopy, supercritical fluids and applications in environmental and propulsion systems, advanced composites, MEMS, nanotechnology, and micro fluidics. He has won many merit and leadership awards by such prestigious organizations as the Society of Automotive Engineers (1. Arch. T. Colwell Merit Award for technical excellence only to top 1% yearly, 2. Ralph R. Teetor Award for outstanding teaching/research/leadership, 3. Forest R. McFarland Award for sustained leadership in professional and educational service and a key contributor to the Continuing Professional Development Group, 4. Appreciation Award for 10 years of dedicated and inspiring  service and commitment to providing quality technical education, and  5. Outstanding Faculty Advisor), American Institute of Aeronautics and Astronautics (Best Publication Award of the Year), Air Force Research Laboratories (1. Outstanding Technical Publication Award, and 2. STAR Team Award for demonstrating world-class combined scientific and leadership achievements), Institute of Liquid Atomization and Sprays Systems (Marshall Award for best publication with lasting contributions), Liquid Propulsion Sub-committee of Joint Army-Navy-NASA-Air Force (JANNAF) (Best Liquid Propulsion Paper Award involving undergraduate/graduate students),  and the 2nd International Symposium on Turbulence and Shear Flow Phenomena (Top 10 Technical Publication Award). He has been a consultant with many organizations such as, Ford, GM, Honda R&D, AFRL, Honeywell, NASA, AFOSR, VW, Bosch, Siemens, NGK, Cummins, and TRW. Through professional societies, Dr. Chehroudi delivers invited professional seminars on Management of R&D Teams and Organizations, Management of Innovation, Combustion and Emission of Pollutants in Automotive and Gas Turbine Engines, Ignition Issues, Gasoline Direct Injection engines, R&D on Homogeneously-Charged Compression Ignition (HCCI) engines, and Liquid Injection Technologies. He has a PhD in Mechanical & Aerospace Engineering and Post-Doctoral Fellow (Princeton University), MS in Mechanical Engineering (Southern Methodist University, Summa Cum Laude), MS in Economics (Swiss Finance Institute, Magna Cum Laude), a senior member of American Institute of Aeronautics and Astronautics Propellant & Combustion Committee (2008-present), and is an Associate Fellow of American Institute of Aeronautics and Astronautics. Dr. Chehroudi acts as a reviewer for many scientific and engineering journals and publishers, has delivered over 200 presentations in technical meetings and to nontechnical audiences, over 20 technical reports (Princeton University, General Motors, Ford Motor Co, Department of Energy, NASA, Air Force Research Laboratory), five 600-plus-page monographs on combustion and emission of pollutants from mobile power plants, ignition technologies, liquid material injection, and nanotechnology,   two book chapters on propulsion system combustion instability and applications of graphene (a nanotech product) in ignition and combustion of fuels, ground-breaking patents on applications and synergy between nanotechnology, light, and chemical reaction for a light-activated distributed ignition of fuel-air mixtures, and has more than 150 publications with extensive experience in both scientific and management areas and intensive trainings in finance and financial engineering

 

 

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