Failure mode analysis of ceramic heating elements and pre-chamber ignition of aviation fuels

The CI (Compression Ignition) engine is a highly utilized system in military aviation and ground vehicles and the primary propulsion system for UAVs (Unmanned Aerial Vehicles). This engine system can effectively operate vehicles on heavy fuel types that fulfill the requirements of the DoD (Department of Defense) single fuel policy, implemented to simplify supply logistics. The practical limitation of the CI engine is that the fuels implemented in these systems require high chemical and physical properties standards to maintain ignitability. During military operations in other parts of the world, procured fuels are not always able to be characterized to meet fuel property standards and thus hamper the performance of the refueled vehicles. Previous studies have demonstrated that sustaining sufficiently high temperatures in ignition assistant devices can mitigate the drawbacks of insufficient fuel quality. However, this results in the accelerated failure of the ignition assistant device. This study analyzes the mechanism that induces accelerated failure in state-of-the-art ceramic COTS (Commercial-Off-The-Shelf) glow plugs in an actual and simulated engine environment to ascertain the material causes that induce accelerated failure in ceramic heating elements. The findings of this study show that the primary failure mechanism in co-annular heating elements is from sintering aid migration and the resulting oxidation of the conductive phase, along with the ignition process in the combustion environments. Additionally, a pre-chamber system is designed and implemented to investigate the effects of more extended fuel-to-air interactions with the glow plug; the results demonstrate that earlier injection times yield similar ignition behavior of kerosene-based aviation of differing reactivities with the glow plug tip at the same temperature. Implementing this injection scheme can potentially reduce the temperature demands of the heating element, reducing degradation.

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

2024

Author dc:creator

• Philippe, Cory

Contributors dc:contributor

• Lee, Tonghun

• Co-annular Heating Element
• Pre-chamber

Statement dc:rights

• Copyright 2024 Cory Philippe

Language dc:language

en, eng

Handle dc:identifier

https://hdl.handle.net/2142/127284

OAI record oai:identifier

https://www.ideals.illinois.edu/oai-pmh?verb=GetRecord&metadataPrefix=etdms&identifier=oai%3Awww.ideals.illinois.edu%3A2142%2F127284