June 22, 2003
June 22, 2003
June 25, 2003
8.293.1 - 8.293.21
CHARACTERIZING THE PERFORMANCE OF THE SR-30 TURBOJET ENGINE
T. Witkowski, S. White, C. Ortiz Dueñas, P. Strykowski, T. Simon
University of Minnesota
“What?!!” exclaimed one student. “Thermodynamics doesn’t work! Why am I even studying this stuff ?!” She was taking her senior lab – an engine lab with the SR-30 engine – and the numbers didn’t work out… on purpose. The professor had set it up that way.
The SR-30 is a small-scale, turbojet engine which sounds and smells like a real engine used to fly commercial aircraft. With an overall length of less than 2.0 feet and an average diameter of 6.5 inches, the SR-30 is equipped with an inlet nozzle, radial compressor, counter-flow combustion chamber, turbine, and exhaust nozzle. Although it can operate on various fuels, diesel fuel is used in the studies described here, and each component is instrumented with thermocouples and pressure gages to allow a complete thermodynamic evaluation. Screaming along at 80,000 rpm and sending out exhaust gas at 500 mph, the SR-30 engine is fun science for students! However, since the SR-30 was essentially designed for one-dimensional measurement and flow analysis, students quickly learn the limitations of these assumptions.
SR-30 Thermodynamic Analysis
The SR-30 gas turbine is modeled by the Brayton cycle which employs air as the working fluid. The basic process is to compress the air, add fuel, burn the air-fuel mixture, and use the energy released to develop thrust. Since the SR-30 engine is not attached to a moving airplane, a bellmouth inlet nozzle is used to create a uniform velocity profile at the compressor inlet and minimize losses. The Brayton cycle for the SR-30 thrust turbine is composed of the following processes: 1) Isentropic acceleration through an inlet nozzle 2) Isentropic compression 3) Constant pressure heat addition through combustion chamber 4) Isentropic expansion through turbine 5) Isentropic expansion across an exhaust nozzle
“Proceedings of the 2003 American Society for Engineering Education Annual Conference & Exposition Copyright © 2003, American Society for Engineering Education”
White, S., & Strykowski, P. (2003, June), Characterizing The Performance Of The Sr 30 Turbojet Engine Paper presented at 2003 Annual Conference, Nashville, Tennessee. https://peer.asee.org/11611
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