Constructive geometry parametrization tools for computer-aided design, analysis, and optimization of aeropropulsive systems

Lauer, Matthew

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https://hdl.handle.net/2142/129238 Copy

Description

Title

Constructive geometry parametrization tools for computer-aided design, analysis, and optimization of aeropropulsive systems

Author(s)

Lauer, Matthew

Issue Date

2025-04-23

Director of Research (if dissertation) or Advisor (if thesis)

Ansell, Phillip J

Doctoral Committee Chair(s)

Ansell, Phillip J

Committee Member(s)

• Goza, Andres
• Merret, Jason M
• Allison, James

Department of Study

Aerospace Engineering

Discipline

Aerospace Engineering

Degree Granting Institution

University of Illinois Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

• Aerodynamics
• Geometry Parametrization
• Parameterization
• MDAO
• Aerodynamic Shape Optimization
• Aeropropulsion
• Aero-propulsion
• Bézier
• B-spline
• NURBS
• Airfoil
• Parametric Surface
• Aerodynamic Design Tool
• Computational Fluid Dynamics
• CFD
• MDO

Abstract

The field of sustainable aviation has enabled advances in aircraft aerodynamics and propulsion through fundamental shifts in power sources. For example, the use of batteries or fuel cells to power aircraft can allow for the use of lighter-weight electric propellers or electric ducted fans that can be distributed across the aircraft in a manner that minimizes battery usage or fuel burn. Instead of mounting these propulsive devices some distance from the aerodynamic surfaces, as is the case in conventional gas-powered turbofan aircraft, embedding these smaller, electric propulsive devices directly into the aerodynamic surfaces can provide aerodynamic benefits through several mechanisms. The concept of embedding propulsive devices into aerodynamic surfaces is referred to throughout this work as "aeropropulsion." Much research has been performed in the area of aeropropulsion in recent years. However, limited research has been done to demonstrate methods for designing and parametrizing the necessarily complex surface geometry associated with aeropropulsive aircraft. These geometries often require complex sets of direct constraints to fully define the relative position, surface shape, and blending between the aerodynamic surfaces and axisymmetric propulsive devices. Additionally, little focus has been devoted to methods for designing these surfaces to the class-A standard, which involves the enforcement of G0, G1, and G2 continuity across adjacent surface patches. Designing aeropropulsive surfaces as close to the class-A standard as possible is important to maximize aerodynamic efficiency. To this end, three software packages were created that simplify the process for designing and parametrizing these types of surfaces. The first of these is Rust-NURBS, which is a Rust library for NURBS curve and surface evaluation with Python bindings. The second is Pymead, which is a Python GUI and API for aerodynamic and aeropropulsive multi-element airfoil design, analysis, and optimization. The third is AeroCAPS, which is a lightweight, script-based CAD package written in Python for the design of class-A aerodynamic geometry using NURBS surfaces. These parametrization tools were used as a vehicle to optimize 2-D aeropropulsive geometries and identify key flow phenomena associated with 2-D and 3-D transonic, aeropropulsive geometries. A series of airfoil matching and single-airfoil shape optimization experiments in Pymead showed that high-degree, curvature-continuous, composite Bézier and B-spline curves give superior results relative to other airfoil parametrization methods. A comparison of a subsonic aeropropulsive analysis in Pymead to an aeropropulsive panel method showed excellent agreement, and comparison to wind tunnel data showed excellent agreement in matching the pressure distribution of the main airfoil. Multipoint shape optimization of a three-element aeropropulsive airfoil system in transonic flow using Pymead yielded a 35% reduction in required mechanical flow power and an 11% reduction in aerodynamic drag. Installation of this airfoil system into a 3-D, aeropropulsive wing using AeroCAPS facilitated a parametric sweep of several high-level blending parameters. Changes to individual blending parameters were shown to retain the smoothness of the wing-nacelle blend and significantly improve the aerodynamic characteristics of the geometry in some cases.

Graduation Semester

2025-05

Type of Resource

Thesis

Handle URL

https://hdl.handle.net/2142/129238

Copyright and License Information

Copyright 2025 Matthew Lauer

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