Active Flow Control and Computation Adaptive Design (AFC-CAD) of Aggressive Offset Diffuser Configurations using a Novel, Programmable Inlet Test Facility
Abstract
Inlet/airframe integration in advanced subsonic and supersonic aircraft over the past 2-3 decades underscored the need for extremely compact, complex-aperture inlet system technologies. Recently, highly compact inlet concepts with aggressive offset diffuser designs were proposed for future Navy aircraft that will use embedded turbomachinery for aerodynamic efficiency. These new diffusers will extend the diffuser centerline angle much beyond present established design guideline regimes including the Classical Moore-KlineDiffusers, Serpentine Diffusers, and Aggressive-Offset Diffusers. It is clear that the performance of these advanced inlet systemswill be hindered by adverse flow characteristics including shock waves, intense streamwise vortices and unsteady, separating flows at the duct turns with substantial losses and distortion. Absent active flow control (AFC), the effects can compromise the turbomachinery#s performance, efficiency, and operability.The proposed Georgia Tech (GT)-NAWCAD experimental-computational research program with support by Boeing IRAD will focus on the development of a radically new approach to the design process of compact inlet systemsfor future Navy aircraft that will be enabled by AFC-Computation Adaptive Design (AFC-CAD) methodologies in which AFC is an integral part of the design stage. These AFC technologies will be incorporated from the inception of diffusers geometric design rather than provide an ad-hoc, post-design performance improvement of a constrained configuration as done in the past. The proposed investigations will develop a reconfigurable surrogate diffuser design testbed integrated with AFC and coupled with numerical simulation design tools that will enable rapid variations of desired design characteristics and thus rapid, cost-effective exploration of diffuserdesigns. Inherent performance shortcomings associated with internal flow will be overcome by iterations of the diffuser geometry and integrated AFC using validated numerical design tools. The AFC-CAD design approach is the culmination of earlier ONR experimental/numerical programs at Georgia Tech, NAWCAD and Boeing that yielded fundamental understanding of the AFC approaches for alleviatingthe adverse effects of the internal flow on propulsion performance.The proposed 3-year research program will demonstrate the utility of the new AFC-CAD approach to diffuser design at takeoff conditions. An daptively programmable, surrogate diffuser testbed integrated with AFC technologies will be designed and constructed at GT using existing infrastructure. The planned experimental/numerical research will use aggressive settings of the programmable diffuser and will characterize the evolution of the internal flow and its sensitivity to alterations of the base configuration and the integrated AFC technologies will be explored to correct for flow distortions and enhance recovery. In parallel, NAWCAD will use RANS, DES, and WMLES with NAWCAD#s computational design tools to simulaeand validate the flow in the programmable diffuser in absence and presence of AFC. Experiments and simulations will iterate parametric settings of the diffuser and AFC to optimize its performance based on the flow#s distortion. The utility of AFC-CAD will be demonstrated experimentally and numerically by coupling a submerged inlet aperture. The proposed research will be supported by BoeingIRAD with consulting on the diffuser design, test matrix development, guidance on inlet geometries, and manufacturing resources. Boeing will integrate GT-NAWCAD data into its framework for conceptual aircraft design exploration. It is anticipated that the proposed collaboration between GT, NAWCAD, and Boeing will help define the design space and geometries of diffusers that are uniquely enabled by AFC and support assessment of their performance benefits. Approved for Public Release.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Sep 11, 2023
- Source ID
- N000142312821
Entities
People
- Ari Glezer
Organizations
- Georgia Tech Research Corporation
- Office of Naval Research
- United States Navy