Green Aviation Reduction of Environmental Impact Through Aircraft Technology and Alternative Fuels

Aircraft emissions currently account for ~3.5% of all greenhouse gas emissions. The number of passenger miles has increased by 5% annually despite 9/11, two wars and gloomy economic conditions. Since aircraft have no viable alternative to the internal combustion engine, improvements in aircraft efficiency and alternative fuel development become essential. This book comprehensively covers the relevant issues in green aviation. Environmental impacts, technology advances, public policy and economics are intricately linked to the pace of development that will be realized in the coming decades. Experts from NASA, industry and academiareview current technology development in green aviation that will carry the industry through 2025 and beyond. This includes increased efficiency through better propulsion systems, reduced drag airframes, advanced materials and operational changes. Clean combustion and emission control of noise, exhaust gases and particulates are also addressed through combustor design and the use of alternative fuels. Economic imperatives from aircraft lifetime and maintenance logistics dictate the drive for "drop-in" fuels, blending jet-grade and biofuel. New certification standards foralternative fuels are outlined. Life Cycle Assessments are used to evaluate worldwide biofuel approaches, highlighting that there is no single rational approach for sustainable buildup. In fact, unless local conditions are considered, the use of biofuels can create a net increase in environmental impact as a result of biofuel manufacturing processes. Governmental experts evaluate current and future regulations and their impact on green aviation. Sustainable approaches to biofuel development are discussed for locations around the globe, including the US, EU, Brazil, China and India.

Part I. Environmental impacts of aviation 1. Noise emissions from commercial aircraft Edmane Envia1.1 Introduction 1.2 Sources of aircraft noise 1.3 Aircraft component noise levels (example) 1.4 Summary 2. Aircraft emissions: gaseous and particulate Changlie Wey and Chi-Ming Lee2.1 Introduction 2.2 Gaseous emissions 2.3 Particle emissions 2.4 Alternative fuels 2.5 Summary 3. Improvement of aeropropulsion fuel efficiency through engine design Kenneth L. Suder and James D. Heidmann3.1 Introduction 3.2 Early history of NASA Glenn Research Center aeropropulsion fuel efficiency efforts, 1943 to 1958 3.3 Introduction of turbofan engines and Improved propulsive efficiency3.4 Energy crisis of 1970s and NASA Aeronautics Response 3.5 NASA’s role in component test cases and computational fluid dynamics development 3.6 Current NASA efforts at reduced fuel consumption 3.7 Summary Part II. Technologies to mitigate environmental impacts 4. Noise mitigation strategies Dennis L. Huff4.1 Introduction 4.2 Noise reduction methods 4.3 Future Noise-Reduction Technologies 4.4 Summary 5. Advanced materials for green aviation Ajay Misra5.1 Introduction 5.2 Lightweight materials 5.3 Smart materials 5.4 High-temperature materials 5.5 Materials for electric aircraft 5.6 Summary 6. C lean combustion and emission control Changlie Wey and Chi-Ming Lee6.1 Introduction 6.2 Products of combustion 6.3 Emissions control 6.4 Engine NOx control strategies 6.5 Tradeoffs involved in reducing NOx emissions 6.6 Summary 7. Airspace systems technologies Banavar Sridhar7.1 Introduction 7.2 Current airspace operations 7.3 Advanced airspace operations concepts 7.4 Next generation air transportation system technologies 7.5 Conclusions 8. Alternative fuels and green aviation Emily S. Nelson8.1 Introduction 8.2 Aviation fuel requirements 8.3 Fuel properties 8.4 Biofuel feedstocks for aviation fuels 8.5 Manufacturing stages 8.6 Life cycle assessment 8.7 Conclusions Appendix. Basic terminology and concepts in hydrocarbon chemistry 9. Overview of alternative fuel drivers, technology options, and demand fulfillment Kirsten Van Fossen, Kristin C. Lewis, Robert Malina, Hakan Olcay and James I. Hileman9.1 Introduction 9.2 Alternative fuel drivers 9.3 Technology options 9.4 Meeting demand for alternative jet fuel 9.5 Conclusions 244 10. Biofuel feedstocks and supply chains: how ecological models can assist with design and scaleup Kristin C. Lewis, Dan F.B. Flynn and Jeffrey J. Steiner10.1 Introduction 10.2 Challenges of developing an agriculturally based advanced biofuel industry 10.3 Potential benefits of scaled-up biofuel feedstock production 10.4 Regionalized biomass production and linkage to conversion technology 10.5 Applying ecological models to biofuel production 10.6 Summary 11. Microalgae feedstocks for aviation fuels Mark S. Wigmosta, Andre M. Coleman, Erik R. Venteris and Richard L. Skaggs11.1 Introduction 11.2 Algae growth characteristics 11.3 Large-scale production potential and resource constraints 11.4 Two-billion gallon per year case study 11.5 Summary and conclusions 12. Certification of alternative fuels Mark Rumizen and Tim Edwards12.1 Introduction 12.2 Background 12.3 ASTM certification process 12.4 U.S. Federal Aviation Administration certification 12.5 Future pathways 13. Environmental performance of alternative jet fuels Hakan Olcay, Robert Malina, Kristin Lewis, Jennifer Papazian, Kirsten van Fossen, Warren Gillette, Mark Staples, Steven R.H. Barrett, Russell W. Stratton and James I. Hileman13.1 Introduction 13.2 Evaluating greenhouse gas emissions and impacts of alternative fuels on global climate change 13.3 Water 13.4 Biodiversity 13.5 Conclusions 14. Perspectives on the future of green aviation Jay E. Dryer14.1 Introduction 14.2 Key factors affecting the future of green aviation 14.3 Required technology for aircraft development and design 14.4 Required technology for greater alternative fuel utilization 14.5 Possible disruptive technologies 14.6 Forecast 14.7 Summary

Emily S. Nelson is a research engineer at the NASA Glenn Research Center (GRC) specializing in interdisciplinary research at the intersection of fluid mechanics and heat transport, materials science, biology and/or human physiology. She received her B.S. in Mechanical Engineering from the Illinois Institute of Technology, Chicago, IL (1983); M.S. in Mechanical Engineering from the Illinois Institute of Technology (1986); and her Ph.D. in Mechanical Engineering from the University of California at Berkeley (1998). Dr. Nelson has been employed as a research engineer by NASA GRC since 1989. She is conducting numerical simulations of industrial algae growth processes, which combine hydrodynamics with biokinetics to evaluate and develop system designs and operating protocols for biomass yield, consumption of waste CO2 generated by a power plant, and power requirements. Dhanireddy Ramalinga "D.R" Reddy, Chief of the Aeropropulsion Division at NASA Glenn Research Center , Cleveland, Ohio, is responsible for providing enabling capabilities to the aerospace community by leading research and developing technology in the areas of turbomachinery, combustion, fuels/propellants, icing, inlets, nozzles, propulsion system simulation, engine systems, and computational methods. He received his Bachelor of Engineering in Mechanical Engineering (1971) from Sri Venkateswara University, A. P., India; Master of Engineering in Aeronautical Engineering (1974) from Indian Institute of Science, Bangalore; and Ph.D. in Aerospace Engineering (1983) from the University of Cincinnati. Dr. Reddy joined NASA GRC in 1991, serving as Chief of the Computational Fluid Dynamics Branch and Senior Consultant, and focusing research on developing a predictive capability to accurately simulate the complex flow features of advanced aerospace propulsion systems.