Computational Assessment of Flow through a High-Flow Nacelle Bypass for Low Supersonic Boom

Sonic boom minimization is a challenge faced by the aviation community to enable high- speed civilian aircraft flying supersonically over populated land. One of the concepts proposed to reduce sonic boom incorporates a high-flow secondary nacelle bypass to enclose the engine and its protrusions where the flow is diverted around a gearbox through a set of inlet and exit guide vanes. To assess the flow quality within the bypass, computational studies are conducted using traditional RANS-based methods. Three levels of geometric complexity are considered—including the full engine, only the aft vane sections, and only one channel from the aft section—to evaluate global and local flow characteristics and to evaluate the influence of different turbulence models on the flow solutions. The aft vane calculations were conducted in “clean” and “vaned” configurations which correspond to experimental models whose data were used for validation purposes. Comparisons between the full engine and detailed single channel calculations show a weak dependence on the turbulence model used for the mean flow predictions as well as strong turbulence-shock interactions. The clean and vaned aft bypass sections exhibit reasonable agreement with the experimental data but show a stronger influence of the turbulence model on predictive accuracy due to a laminar-turbulent transition affecting the inflow velocity profile.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Aerospace Engineering

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2011

Author dc:creator

• Jain, Nishan

Contributors dc:contributor

• Bodony, Daniel J.

• Reynolds-averaged Navier-Stokes (RANS)
• turbulence modeling
• sonic boom minimization
• high-flow nacelle bypass
• gearbox
• fairing
• blockage
• turbulence shock interaction

Statement dc:rights

• Copyright 2011 by Nishan Jain

Language dc:language

en

Handle dc:identifier

http://hdl.handle.net/2142/26111

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/26111