Power-Based Study of Boundary Layer Ingestion for Aircraft Application

Description

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. Preface Acknowledgements Contents Nomenclature Latin Symbols Greek Symbols Subscripts Abbreviations 1 Introduction 1.1 Growth in Aviation 1.2 The Main Power Requirements of Aircraft 1.3 Opportunities in Propulsion Integration 1.4 Research Objective 1.5 Book Overview References 2 Propulsion Integration 2.1 Characteristics of Uninstalled Propulsion 2.2 Introduction to Propulsion Integration 2.2.1 Thrust/Drag Bookkeeping 2.2.2 Propulsion Integration for Aircraft with Turbofan Engines 2.2.3 Propulsion Integration for Aircraft with Turboprop Engines 2.3 Historical Survey of Propellers in the Wake 2.3.1 Ship Propellers 2.3.2 Pusher Propellers for Aircraft 2.4 Possible Benefits of Boundary Layer Ingestion 2.5 The Challenges of Boundary Layer Ingestion 2.5.1 Inlet Distortion 2.5.2 Noise Emission Issues 2.5.3 Losses in the Inlet 2.5.4 Other Installation Issues References 3 A Theoretical Analysis of Boundary Layer Ingestion and Wake Ingestion 3.1 Introduction 3.2 Power Balance Method and Wake System 3.3 The Impact of WI on Power Consumption 3.3.1 Power Balance for a General Wake Ingestion Actuator Disc 3.3.2 Power Conservation for a WI Integrated Vehicle 3.4 Integration Issues for the BLI Configuration 3.4.1 Interaction Impact on Body Profile Drag 3.4.2 Power Balance for the Aircraft Utilizing BLI 3.5 Conclusions References 4 Power-Based Analysis of Boundary Layer Ingestion Through Numerical Simulations 4.1 Power Balance Method in Computation Fluid Dynamics 4.1.1 Compatibility Between Finite Volume Method and Power Balance Analysis 4.1.2 Computational Domain 4.1.3 Power Balance Analysis of a Simple Jet in Laminar Flow 4.2 Mechanisms of Boundary Layer Ingestion in Laminar Flow 4.2.1 An Actuator Disc Model in Laminar Flow 4.2.2 A Flat Plate Model in Laminar Flow 4.2.3 An Integrated Vehicle in Laminar Flow 4.3 Power Bookkeeping in Turbulent Flows 4.3.1 A Flat Plate in Turbulent Flow 4.3.2 An Integrated Vehicle in Turbulent Flow 4.4 Summary of Numerical Simulations References 5 Experimental Study of the Flow Mechanisms Associated with a Propulsor Ingesting a Body Wake 5.1 Introduction 5.2 Experimental Set-Up and Procedure 5.2.1 Test Configurations 5.2.2 Wind Tunnel and Experimental Models 5.2.3 Stereoscopic PIV Measurement Set-Up 5.2.4 Pressure Measurements Using the Pitot-Static Tube 5.2.5 Measurement Uncertainties 5.3 Experimental Results and Analysis 5.3.1 Results of the Sensor Measurement 5.3.2 PIV-Based Flow Field Analysis 5.3.3 Comparison and Discussion 5.4 Conclusions References 6 Conclusions and Recommendations 6.1 Observations in Theoretical, Numerical, and Experimental Research 6.2 Conclusions 6.3 Recommendations Appendix Integral Force and Power Terms of the Flow Field