This book presents research on Boundary Layer Ingestion (BLI). BLI is an aircraft-engine integration technique that aims at integrating the aircraft and the propulsion system such that the overall aircraft fuel consumption can be reduced. In this research, theoretical analysis suggests that the minimization of total power consumption should be used as a design criterion for aircraft utilizing BLI rather than focusing on the minimization of drag. Numerical simulations are performed, and the simulation results are processed using the PBM to support the theoretical analysis. Furthermore, an experimental study is carried out with a focus on the power conversion processes involved for a propulsor operating in the wake. Stereoscopic PIV is employed in order to visualize the flow and understand the physics. The so-called Power-based Method is used to quantify the power conversion mechanisms. The results prove that the dominant mechanism responsible for the efficiency enhancement is due to the utilization of body wake energy by the wake ingesting propeller. In short, the importance of wake energy flow rate in understanding the BLI phenomenon is highlighted. This book will be useful for researchers in the field of aircraft propulsion, aircraft aerodynamics, and airframe propulsion integration.

The primary human activities that release carbon dioxide (CO2) into the atmosphere are the combustion of fossil fuels (coal, natural gas, and oil) to generate electricity, the provision of energy for transportation, and as a consequence of some industrial processes. Although aviation CO2 emissions only make up approximately 2.0 to 2.5 percent of total global annual CO2 emissions, research to reduce CO2 emissions is urgent because (1) such reductions may be legislated even as commercial air travel grows, (2) because it takes new technology a long time to propagate into and through the aviation fleet, and (3) because of the ongoing impact of global CO2 emissions. Commercial Aircraft Propulsion and Energy Systems Research develops a national research agenda for reducing CO2 emissions from commercial aviation. This report focuses on propulsion and energy technologies for reducing carbon emissions from large, commercial aircraftâ€" single-aisle and twin-aisle aircraft that carry 100 or more passengersâ€"because such aircraft account for more than 90 percent of global emissions from commercial aircraft. Moreover, while smaller aircraft also emit CO2, they make only a minor contribution to global emissions, and many technologies that reduce CO2 emissions for large aircraft also apply to smaller aircraft. As commercial aviation continues to grow in terms of revenue-passenger miles and cargo ton miles, CO2 emissions are expected to increase. To reduce the contribution of aviation to climate change, it is essential to improve the effectiveness of ongoing efforts to reduce emissions and initiate research into new approaches.

This thesis will examine potential propulsive and aerodynamic benefits of integrating a Boundary-layer Ingestion (BLI) propulsion system with a typical commercial aircraft using the Common Research Model geometry and the NASA Tetrahedral Unstructured Software System (TetrUSS). The Numerical Propulsion System Simulation (NPSS) environment will be used to generate engine conditions for CFD analysis. Improvements to the BLI geometry will be made using the Constrained Direct Iterative Surface Curvature (CDISC) design method. Previous studies have shown reductions of up to 25% in terms of propulsive power required for cruise for other axisymmetric geometries using the BLI concept. An analysis of engine power requirements, drag, and lift coefficients using the baseline and BLI geometries coupled with the NPSS model are shown. Potential benefits of the BLI system relating to cruise propulsive power are quantified using a power balance method and a comparison to the baseline case is made. Iterations of the BLI geometric design are shown and any improvements between subsequent BLI designs presented. Simulations are conducted for a cruise flight condition of Mach 0.85 at an altitude of 38,500 feet and an angle of attack of 2° for all geometries. A comparison between available wind tunnel data, previous computational results, and the original CRM model is presented for model verification purposes along with full results for BLI power savings. Results indicate a 14.3% reduction in engine power requirements at cruise for the BLI configuration over the baseline geometry. Minor shaping of the aft portion of the fuselage using CDISC has been shown to increase the benefit from boundary-layer ingestion further, resulting in a 15.6% reduction in power requirements for cruise as well as a drag reduction of eighteen counts over the baseline geometry.

Introduction to the Theory of Flow Machines details the fundamental processes and the relations that have a significant influence in the operating mechanism of flow machines. The book first covers the general consideration in flow machines, such as pressure, stress, and cavitation. In the second chapter, the text deals with ducts; this chapter discusses the general remarks, types of flow, and mixing process. Next, the book tackles the types of cascades, along with its concerns. The closing chapter covers the flow machine and its components, such as turbine, wheels, engines, and propellers. The text will be of great use to mechanical engineers and technicians.

As recently as the summer of 2001, many travelers were dreading air transportation because of extensive delays associated with undercapacity of the system. That all changed on 9/11, and demand for air transportation has not yet returned to peak levels. Most U.S. airlines continue to struggle for survival, and some have filed for bankruptcy. The situation makes it difficult to argue that strong action is urgently needed to avert a crisis of undercapacity in the air transportation system. This report assesses the visions and goals for U.S. civil aviation and technology goals for the year 2050.

Sustainable aviation is a long-term strategy to provide innovative solutions to the industry’s environmental challenges. The International Symposium on Sustainable Aviation is a multi-disciplinary symposium that presents research on current sustainability-based issues and future trends in aviation from an economic, social, and environmental perspective. The conference provides a platform offering insights on a broad range of current issues in aviation, such as aviation and environment, commercial air transport, regulations and policy, sustainable aerospace vehicles and technologies, and environmental modeling and measurements. The ISSA symposium allows researchers, scientists, engineers, practitioners, policymakers, and students to exchange information, present new technologies and developments, and discuss future direction, strategies, and priorities in sustainable aviation topics.

Green Aviation is the first authoritative overview of both engineering and operational measures to mitigate the environmental impact of aviation. It addresses the current status of measures to reduce the environmental impact of air travel. The chapters cover such items as: Engineering and technology-related subjects (aerodynamics, engines, fuels, structures, etc.), Operations (air traffic management and infrastructure) Policy and regulatory aspects regarding atmospheric and noise pollution. With contributions from leading experts, this volume is intended to be a valuable addition, and useful resource, for aerospace manufacturers and suppliers, governmental and industrial aerospace research establishments, airline and aviation industries, university engineering and science departments, and industry analysts, consultants, and researchers.

This thesis presents the results of experiments carried out at NASA Langley Research Center (LaRC) 14'x22' Subsonic Wind Tunnel to determine the aerodynamic boundary layer ingestion (BLI) benet for the D8 aircraft advanced transport concept. The experiments involved a back-to-back comparison between two D8 aircraft configurations: a podded propulsion system (non-BLI) and a fuselage integrated propulsion system (BLI). The BLI benet was evaluated from ow surveys upstream and downstream of the propulsor using a rotating rake system for the two configurations. The BLI benefit, defined as the mechanical flow power saving at cruise conditions (zero net streamwise force), from the BLI configuration relative to the non-BLI configuration, was found to be 8.2% +/- 0:8%. The experimental-computational approach and the sensitivity analysis of the estimated BLI benefit to uncertainties such as flow angles and instrumentation errors are described in the thesis. The benefits and drawbacks of the rotating rake measurement technique used in the D8-series powered model aircraft experiments are also discussed.

The book is written for engineers and students who wish to address the preliminary design of gas turbine engines, as well as the associated performance calculations, in a practical manner. A basic knowledge of thermodynamics and turbomachinery is a prerequisite for understanding the concepts and ideas described. The book is also intended for teachers as a source of information for lecture materials and exercises for their students. It is extensively illustrated with examples and data from real engine cycles, all of which can be reproduced with GasTurb (TM). It discusses the practical application of thermodynamic, aerodynamic and mechanical principles. The authors describe the theoretical background of the simulation elements and the relevant correlations through which they are applied, however they refrain from detailed scientific derivations.