Session: 01-01: Aero-engine Operation in Harsh Environments

Submission Number: 179147

Experimental Characterization of Vibrational Behavior in Unmanned Aircraft Micro-Turbojet Engines 

This paper presents an experimental investigation into the vibrational behavior of micro-turbojet engines. Excessive vibrations in turbomachinery have the possibility to shorten the life of critical components, such as bearings, which may result in catastrophic failure during operation. Though there is ample literature on large-scale turbomachinery such as gas turbine engines for large aircraft and ground power applications, little is known about the vibrational characteristics of small-scale micro-turbojets. Therefore, there is a critical need to understand these characteristics in order to develop mitigation strategies for vibration in micro-turbojet powered unmanned aircraft applications. For the purposes of this study, “Micro-Turbojet” encompasses engines that typically operate at rotational speeds greater than 60,000 rpm and have a mass flow rate less than 5 lbm/sec. The micro-turbojet engines tested in this study ranged from 15-lbf to 70-lbf thrust class. Vibration data was acquired using a monitoring system utilizing accelerometers and a data acquisition program written for recording high-frequency response and real-time analysis. The accelerometers were fixed directly to the case of each engine and testing was done outside on a mobile, static test stand designed for micro-turbojet research. Systematic characterization of vibrational modes was performed during operation from idle to maximum throttle in order to capture all modes present through the rotational speed range. The vibration analysis revealed that the smaller engines exhibited distinct subsynchronous features associated with structural or acoustic modes, while the larger engines were increasingly dominated by higher-order harmonic content and aerodynamic forcing.

Presenting Author: Jarred Henderson Oklahoma State University

Presenting Author Biography: Second-year master's student with prior industry experience in jet engine balancing. Graduate research focuses on vibration analysis in micro-turbojet engines, emphasizing rapid design methodologies and integrated engine health monitoring systems. Current work involves developing compact propulsion architectures with embedded diagnostic capabilities for experimental and operational environments.

Authors:

Jarred Henderson Oklahoma State University
Brody Richarrdson Oklahoma State University
Connor Schmitt Oklahoma State University
Ryan Hough Oklahoma State University
Sam Mooney Oklahoma State University
Kurt Rouser Oklahoma State University