ORCID

0009-0004-0279-3259

Keywords

Sub-ambient ammonia, Sustainable aviation, Fuel storage system, Fuel delivery system, Narrow-body aircraft, Thermal–structural analysis, Ammonia boil-off, Tank pressurization, Vacuum-jacketed piping, Aircraft systems integration

Subject Categories

Aerospace Engineering | Propulsion and Power

Abstract

This study develops an integrated design framework for a sub-ambient anhydrous-ammonia fuel storage and delivery system for narrow-body commercial aircraft, using the Boeing 737 MAX 8 as the baseline platform. Ammonia was selected because it contains no carbon in its molecular structure, benefits from an established global production and distribution infrastructure, and offers more practical storage conditions than several alternative carbon-free energy carriers. However, its relatively low energy density, toxicity, material-compatibility requirements, and combustion hazards require substantial modifications to power conventional commercial aircraft fuel storage and delivery systems.

The study proposes an integrated design and initial analysis of a sub-ambient ammonia fuel storage and delivery system suitable for installation on a Boeing 737 MAX 8 narrow-body aircraft. The design is unified by addressing tank geometry, insulation and thermal management, tank pressure dynamics, structure assessment, aircraft packaging, and preliminary design of the fuel delivery system. The approach includes the design of the tank and estimation of the heat transfer through the cabin-side and ground-side thermal resistance networks, calculation of ammonia boil-off, simulation of the pressure transient response of the enclosed tank during typical ground operations, and preliminary design of fuel delivery lines based on mass flow rate, velocity, pressure drop, pipe wall thickness, and insulation needs.

Geometries and aircraft packaging are designed in SolidWorks. Reduced-order thermal predictions were compared with ANSYS Fluent conjugate heat-transfer simulations. Transient multiphase simulations were then used to evaluate short-term heat flux, temperature evolution, vapor generation, and liquid–vapor interface behavior. A reduced-order thermodynamic model was used to predict tank pressure and temperature changes caused by ammonia vapor accumulation within the closed ullage volume. ANSYS Mechanical is used to assess the initial thermal-structural response of the dual-lined and honeycomb-reinforced tank under the selected design-pressure and temperature loads. The structural analysis is performed as a preliminary design screening rather than a thorough design and compliance assessment procedure.

The study produced a conceptual tank configuration, liquid and vapor line dimensions, a reference pump selection, and a preliminary routing architecture for the Boeing 737 MAX 8. Although a parametric optimization was not performed, the study identified the principal tradeoffs among tank mass, heat ingress, boil-off, pressure rise, structural response, line diameter, pressure loss, pump requirements, and aircraft packaging

Completion Date

2026

Semester

Summer

Committee Chair

Jayanta Kapat

Degree

Master of Science in Aerospace Engineering (M.S.A.E.)

College

College of Engineering and Computer Science

Department

Mechanical and Aerospace Engineering

Format

PDF

Document Type

Thesis

Language

English

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