Bruce Chehroudi, PhD

 

Dr. Chehroudi  has accumulated years of technical and leadership experiences in different capacities and organizations. This includes such positions as Professor and Department Head, Mechanical Engineering Department at Arkansas Tech University and Interim Head for the Electrical Engineering Department at Arkansas Tech University, Managing Director at Advanced Technology Consultants, Principal Scientist and Group Leader at the Engineering Research Consultants Inc (appointed at Air Force Research Laboratory (AFRL)), Chief Scientist at Raytheon STX, Visiting Technologist at Ford’s Advanced Manufacturing Technology Development (AMTD) center, tenured Professor of Mechanical Engineering at Kettering University and University of Illinois, and served as a Senior Research Staff/Research Fellow/Post-doctorate 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 (SAE):

American Institute of Aeronautics and Astronautics (AIAA): 

 Air Force Research Laboratories (AFRL) and Air Force Office of Scientific Research (AFOSR)

 Institute of Liquid Atomization and Sprays Systems (ILASS):

 Liquid Propulsion Sub-committee of Joint Army-Navy-NASA-Air Force (JANNAF):

 2nd International Symposium on Turbulence and Shear Flow Phenomena:

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.

Dr. Chehroudi has been involved in, and managed, a number of multimillion-dollar R&D programs with successful results that are  being currently used, either as design tools for product development, or have already been incorporated in existing products. Some non-limiting samples are cited here. His rapidly-scanning laser Doppler velocimeter design was the fastest scanner at the time, which was used to characterize separated turbulent boundary layers (turbulence, auto- and cross- correlations. Journal of Fluid Mechanics) similar to what occurs on airplane wings and gas turbine compressors. Space-time correlation coefficients in the backflow region of a separated flow are reported and analyzed for the first time in the literature.  Ten (10) years after, this work passed the test of time and was  selected as an outstanding contribution in the SPIE Milestone Series in Laser Diagnostics, edited  by Ronald  J. Adrian and Brian  J. Thompson. Read about the stringent selection process here.  One of his works at Princeton University Engine and Spray Research Laboratory, working with the late Professor F. V. Bracco (also see Aerospace Research & Education at Princeton), sponsored by the Department of Energy (DOE) Direct Injection Stratified Charge (DISC) engine program, a consortium by GM Research Lab, SANDIA Combustion Research Facility, Los Alamos National Lab, and Princeton University,  was related to characterization of the dense intact core region in diesel fuel sprays. His multidisciplinary team management and innovative electrical conductivity method produced results that have also time-tested and considered highly-creative and instrumental for the modeling/simulation as well as design of fuel injectors in such engines. Results have been used in the development and validation of the fuel atomization section of the KIVA computer program, being the backbone of most combustion modeling simulation in internal combustion engines. This research, was the first that offered information on the shape of the intact core of the full-cone sprays in addition to its length. For this work he and his team members were awarded one of the most prestigious technical merit award (Arch T. Colwell Merit Award) by the Society  of Automotive Engineers (SAE). Also, another work conducted on aircraft and ground-based  gas turbine engine fuel spray combustion and emission issues was cited in the CRC Handbook of Fluid Dynamics as "significant example of applied engineering research done on the subject with many commercial applications". His interacting-sprays (or impinging-sprays) injection strategy (Sponsored by the General Motors) for simultaneous NOx and soot reduction/control, a cross fertilization of  rocket F-1 engine technology to diesel engines, is  considered an ingenious approach with highly flexible features to produce not only  "pilot and split injections," but additional strategies for emission reduction and efficiency improvements.  A chapter is dedicated to "Interacting Sprays" injection by Prof. J. B. Greenberg in the Handbook of Atomization and Sprays. This concept has recently been used in diesel engines modified for the early-injection homogeneously-charged compression ignition. His original research established a new research track on applications of interacting sprays or impinging sprays in diesel engines (watch  Chehroudi's presentation on Interacting Sprays).  See a video describing details of the Interacting Sprays Injection System Test Setup (High-speed internet is recommended).  Yet another example, is his management and technical  leadership on a program related to supercritical cryogenic liquid propellants used in H2/O2 Space Shuttle Main Engine  (SSME).

This latter work, and his team, were recognized by another highly prestigious technical merit award through Combustion and Fuel Technical Committee of the American Institute of Aeronautics and Astronautics (AIAA). He was the first to demonstrate quantitatively that the shear layer of the liquid propellants injected into thermodynamic supercritical condition grows and spreads similar to incompressible but variable-density gaseous mixing layers. This was shown through jet's initial shear layer growth rate measurements and fractal analysis. Dr. Chehroudi's seminal work implies that atomization theories based upon Rayleigh-Taylor instabilities are no longer applicable to supercritical situation where there is no longer a surface tension; instead, the fluid behavior is determined by turbulence and diffusional mixing (see Dr Josette Bellan).  In a recent book titled "Droplet Dynamics Under Extreme Ambient Conditions" edited by Schulte, K., Tropea, C., and Weigand, B, 2022,   and in a paper titled "Modeling and Simulation of a Turbulent Multi-component Two-phase Flow Involving Phase Change Processes Under Supercritical Conditions," the authors (Kuetemeier, D. and Sadiki, A.)   from Technische Universitat Darmstadt   wrote "For the model validation in this class of investigations the detailed study by Chehroudi, who neatly generated and compared various experimental data from different liquid and gas jets as function of pressures, remains state of the art." His Invited Review article on this subject is titled "Recent Experimental Efforts on High-Pressure Supercritical Injection for Liquid Rockets  and Their Implications".  Dr. Chehroudi's newly-proposed combustion instability theory for liquid rocket engines is yet another unique contributions recognized by his peers as innovative and highly creative. 

His  work also expanded into frontiers of nanotechnology  by pioneering the only nanotechnology-based light-activated volumetrically-distributed ignition system for both automotive (HCCI) and rocket engine applications. His creative /original  idea and  the R&D work directed by him, delivered an elegant answer to a technological barrier  referred to as "controlled autoignition", being at the heart of the next generation advanced HCCI engines. His imagination, initiative, leadership, and technical vision in this area have,  not only set the stage and the R&D roadmap  for new applications of nanotechnology in volumetrically-distributed fuel/propellant photo ignition for the first time in literature with subsequent followers, but also convinced program managers at AFOSR in creating a fully-funded five year program for this research work while at AFRL. Subsequent nanotech-based photo ignition efforts at AFRL were guided by his strategic plan, visionary thinking, and original  imaginations.  His work on synergy between  supercritical fluids and nanotechnology  can be found  in an invited review article titled  Supercritical Fluids: Nanotechnology and  Select Emerging Applications.

Dr Chehroudi's past research projects had contributions and impacts in a number of areas. First, on account of the multidisciplinary nature of most efforts, they enhanced inter- and intra-organizational communication and created synergistic joint efforts. Second, many of them led to fundamental understanding of the underlying physics of the problem. Third, they substantially enriched the visibility and scientific credibility of the division. Fourth, they led into tremendous performance improvement on the existing products and led to either new products/technologies or product ideas. Fifth, many of them won technical merit awards from prestigious scientific/engineering societies (listed in the AWARDS section). Sixth, sustained award-winning high-quality publications and reports with useful results which encouraged continued support by funding agencies. 

Dr. Chehroudi 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 of Technology, top 5%).  He is a senior member of the American Institute of Aeronautics and Astronautics'  Propellant & Combustion Committee (2008-present) and  was honored an Associate Fellow  title from the American Institute of Aeronautics and Astronautics (AIAA.org).

Throughout years, Dr. Chehroudi has evolved into a leader who forms synergy, cultivates a culture of innovation and collaboration, communicates unambiguously and respectfully, builds trust and consensus, injects motivation and inspiration, and guides/encourages strategic/systemic thinking. These incipient talents are those he has nurtured through interactions with colleagues/mentors which have been critical and precious elements facilitating stellar achievements from his teams. Moreover, he brings extensive level of technical leadership and presentation skills (to technical/nontechnical, ( C-level, & clients) in a broad range of disciplines/technologies, which are instrumental in leading multidisciplinary teams, in technology development, forecasting and transfer, as well as in revenue-generating new product development (NPD) and R&D efforts. Lastly, when a solid educational background (PhD/MS/BS in Mechanical/Aerospace Engineering and MS in Economics/Management) is added to the mix, the package as a whole creates a multidimensional professional who understands and quickly grasps the importance and potential of research/development activities for commercialization in a wide range of science, technology, and engineering fields and who markets such opportunities and ideas towards goals/objectives of the organization.

He acts as a reviewer for many scientific and engineering journals and publishers, has been a Technical  Editorial Director of the Powertrain International, Editorial Board of the Journal of Combustion by  Hindawi, and   has delivered over 200 presentations in technical meetings/conferences (SAE, AIAA, ASME, Professional Education Seminars, etc)  and to nontechnical audiences and has over 20 technical reports (Princeton University, General Motors, Ford Motor Co, Department of Energy, NASA, Air Force Research Laboratory).

He has also produced five 600-plus-page monographs on combustion and emission of pollutants from mobile power plants, ignition technologies, liquid fuel/material injection, and nanotechnology,   two book chapters on liquid propellants and combustion instability(*) and applications of graphene (a nanotech product) in ignition and combustion of fuels/propellants, ground-breaking patents on applications and synergy between nanotechnology, light, and chemical reaction for a light-activated volumetrically-distributed ignition of fuel-air mixtures and liquid fuel sprays with applications in Low Temperature Gasoline Combustion (LTGC) or HCCI, and liquid rocket engines.

Dr. Chehroudi has more than 150 publications with extensive experience in both scientific and management areas and intensive trainings in finance and financial engineering. His time-tested innovative contributions will continue (as it has) no matter what he does or which organization he will be affiliated. 

(*) The Encyclopedia of Aerospace Engineering represents a major publishing initiative by John Wiley and Sons Inc.,  to establish a high quality, carefully coordinated reference work that will enhance education, training and research in this complex and demanding field.

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