Liquid Atomization, Spray, and Fuel Injection in Aircraft Gas Turbine Engines


Atomization of liquids is at the heart of operations of many of the devices we use on a daily basis. From our shower in the morning (water atomization at the shower head), to liquid-fueled engines in ground transportation (gasoline and diesel engines), to gas turbine in airplanes/power stations and rocket engines. Other areas such as electrostatic car-body spray painting, agricultural crop spraying, ink jet printing, pharmaceutical nebulizers, spray drying, and chemical liquid rockets, are just a few examples of the very wide applications of the liquid spray production technology.

In the aerospace industry, the engine thrust, efficiency, and the emission levels are directly related to the performance of the liquid fuel injector designs. For this reason, R&D activities in this area have intensified in the past two decades in a quest to design and operate efficient and low-emission gas turbine engines. It is imperative then individuals involved in research, design, and operation have the requisite knowledge and training to choose intelligent and innovative approaches when it comes to liquid fuel nozzle and its optimum performance.

This seminar is about understanding the processes of liquid atomization and spray formation and relating this understanding to fuel injection systems and emission of pollutants in modern engines. The approach in this course is to build sufficient background through introduction of a consistent and widely-used terminology in sprays and atomization. Justifications, reasons, and purposes of the liquid atomization and spray formation are discussed along with presentation of different designs of atomizers and nozzles employed in various industries. Characterization methods of sprays are discussed after the definition and meaning of different averaged liquid droplet diameters are touched. Droplet size measurement devices are covered and examples are shown. Armed with these critical background information, the focus of the course is then heavily directed to gas turbine fuel nozzle designs and their performance requirements for optimum engine operation with lowest possible emission of harmful pollutants.

Key Topics:

  • Understand and be familiarized with important terminology commonly used in atomization and sprays
  • Gain a general physical understanding of the important processes in atomization and spray formation
  • Possess adequate background and foundation to educate yourself beyond the depth and topics covered
  • Be able to intelligently judge, adapt, and, transfer technological advances from one discipline to the other
  • Understand effects of fuel nozzle design and operating conditions on engine performance, combustion and emission of pollutants
  • Be able to communicate intelligently with engineers working on fuel nozzle and fuel system design aspects in your company
  • Grasp the technology and the logic behind different injector designs
  • Gain sufficient knowledge to intelligently contribute to human being's efforts in minimizing emission of pollutants and maximizing efficient usage of earth's energy resources
  • Anticipate future trends and technology developments in fuel nozzles
  • Learn and appreciate the role the fuel nozzles play in combustion and emission and how it is used to provide guidance in design of low-emission combustion systems
  • Effectively contribute to the design of the critical engine components affected by the fuel nozzle performance

Who Should Attend:

This seminar will be especially valuable for engineers, technical and project managers, researchers, and academicians in the aerospace industries. In the aviation industry, engineers working on the design of components for high efficiency and performance of combustion engines, particularly those directly and indirectly involved in reducing emission of harmful pollutants from combustion engines, will highly benefit from this course. Additionally, this course provides adequate background for engineers and managers in contact with those directly involved in the fuel nozzle systems. Therefore, this experience prepares the attendees for a more efficient and intelligent communication in an interdisciplinary technological environment. The course is also of interest to academicians wishing exposure to the field and those engineers active in development and applications of software, modeling in-cylinder injection combustion and emission processes.

General Course Information:

  • Type of Course: Instructor-Led Short Course
  • Course Level: Intermediate
  • Course Length: 2 days
  • AIAA CEU's available: Yes
  • Description of the Atomization Process
  • Disintegration of the liquid jets
  • Disintegration of liquid sheets
  • Drop breakup in air flow, turbulent flow, and viscous flow
  • Types of Atomizers and their design features
  • Spray drop size distribution and measurements
  • Drop and spray evaporation
  • Fuel spray in the combustor confines
  • Spray flame in gas turbine combustors
  • Spray flame stabilization
  • Effects of fuel nozzle design and operating parameters on spray characteristics and combustor performance
  • Effects of fuel nozzle design and operating parameters on emission of pollutants
  • Matching of Fuel spray with the combustor
  • Fuel nozzles for Lean Direct Injection
  • Advanced concepts


Dr. Bruce Chehroudi, has accumulated years of technical and leadership experiences in different capacities and organizations. This includes such positions as President at Advanced Technology Consultants, 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 Fellow at Princeton University. Dr. Chehroudi directed numerous multi-million 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, GE, Bosch, Siemens, NGK, Cummins, UTRC, 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), and BS in Mechanical Engineering (Sharif University).

He is a senior member of American Institute of Aeronautics and Astronautics Propellant & Combustion Committee (2008-present) and 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 fuel 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 training in finance and financial engineering.


AIAA Training Links