Optimal Shape Design of Mail-Slot Nacelle on N3-X Hybrid Wing-Body Configuration

System studies show that a N3–X hybrid wing-body aircraft with a turboelectric distributed propulsion system using a mail-slot inlet/nozzle nacelle can meet the environmental and performance goals for N+3 generation transports (three generations beyond the current air transport technology level) set by NASA’s Subsonic Fixed Wing Project. In this study, a Navier-Stokes flow simulation of N3–X on hybrid unstructured meshes was conducted, including the mail-slot propulsor. The geometry of the mail-slot propulsor was generated by a CAD (Computer-Aided Design)-free shape parameterization. A novel body force model generation approach was suggested for a more realistic and efficient simulation of the flow turning, pressure rise and loss effects of the fan blades and the inlet-fan interactions. Flow simulation results of the N3-X demonstrates the validity of the present approach. An optimal Shape design of the mail-slot nacelle surface was conducted to reduce strength of shock waves and flow separations on the cowl surface.

[1]  Rodrick V. Chima,et al.  Rapid Calculations of Three-Dimensional Inlet/Fan Interaction , 2007 .

[2]  Kazuhiro Nakahashi,et al.  Direct Surface Triangulation Using Stereolithography Data , 2002 .

[3]  Kazuhiro Nakahashi,et al.  Unstructured adjoint method for Navier-Stokes equations , 2005 .

[4]  David Rodriguez,et al.  A multidisciplinary optimization method for designing boundary layer ingesting inlets , 2001 .

[5]  Kidambi Sreenivas,et al.  Demonstration of Sub-system Level Simulations: A Coupled Inlet and Turbofan Stage , 2012 .

[6]  Ronald T. Kawai.  Acoustic Prediction Methodology and Test Validation for an Efficient Low-Noise Hybrid Wing Body Subsonic Transport , 2011 .

[7]  Garret N. Vanderplaats,et al.  Numerical Optimization Techniques for Engineering Design: With Applications , 1984 .

[8]  Kazuhiro Nakahashi,et al.  Multiple Marching Direction Approach to Generate High-Quality Hybrid Meshes , 2007 .

[9]  B. Kulfan.  Universal Parametric Geometry Representation Method , 2008 .

[10]  Jeff Defoe.  Inlet swirl distortion effects on the generation and propagation of fan rotor shock noise , 2011 .

[11]  Garret N. Vanderplaats,et al.  Numerical optimization techniques for engineering design , 1999 .

[12]  F. Menter.  Two-equation eddy-viscosity turbulence models for engineering applications , 1994 .

[13]  Yifang Gong,et al.  A computational model for rotating stall and inlet distortions in multistage compressors , 1999 .

[14]  Meng-Sing Liou,et al.  Flow Simulation of Supersonic Inlet with Bypass Annular Duct , 2010 .

[15]  M. A. Sargeant,et al.  Airframe Design for Silent Fuel-Efficient Aircraft , 2010 .

[16]  Gerald V. Brown,et al.  An Examination of the Effect of Boundary Layer Ingestion on Turboelectric Distributed Propulsion Systems , 2011 .

[17]  Meng-Sing Liou,et al.  Comparison of the AUSM(+) and H-CUSP Schemes for Turbomachinery Applications , 2003 .

[18]  Yifang Gong,et al.  Actuator duct model of turbomachinery components for powered-nacelle Navier-Stokes calculations , 2000 .

[19]  Thomas K. Walker.  The development and requirements of a body force database from two-dimensional and streamline curvature calculations , 2009 .

[20]  R. H. Liebeck,et al.  Design of the Blended Wing Body Subsonic Transport , 2002 .

[21]  Y. Saad,et al.  GMRES: a generalized minimal residual algorithm for solving nonsymmetric linear systems , 1986 .

[22]  Rodrick V. Chima.  Calculation of Multistage Turbomachinery Using Steady Characteristic Boundary Conditions , 1998 .

[23]  Christopher E. Hughes,et al.  Aerodynamic Performance of Scale-Model Turbofan Outlet Guide Vanes Designed for Low Noise , 2002 .

[24]  Meng-Sing Liou,et al.  A sequel to AUSM, Part II: AUSM+-up for all speeds , 2006, J. Comput. Phys..