This paper presents a numerical investigation of lobed mixer performance at experimentally validated low speed conditions and conditions representative of high speed engine operation. The purpose of this study was to first assess and understand how variations in bypass-to-core area ratio (AR) can affect engine performance, then isolate those effects to determine the efficacy of increasing the number of mixer lobes. The area ratio was manipulated via adjustment of the lobe crest and valley radiuses. No other geometric features were altered in any of the 5 mixers studied (12-lobe AR of 3, 2.5 and 3.5, 16-lobe AR of 3 and 18-lobe AR of 3). Results indicate that performance can be affected by area ratio. Low-speed results showed that pressure loss and thrust output were improved at lower area ratios. High speed results showed the opposite. This behavior is believed to be the result of a bypass-to-core momentum ratio difference between the two test conditions. These effects were avoided when studying the number of lobes by maintaining a constant area ratio. Results indicate that adding lobes enhanced exhaust mixing but hampered performance at low speed conditions. No appreciable performance difference was observed at high speed conditions. Fluid viscosity and associated viscous mixing losses are believed to be the parameters at fault for the reduced low-speed performance results.
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ASME Turbo Expo 2014: Turbine Technical Conference and Exposition
June 16–20, 2014
Düsseldorf, Germany
Conference Sponsors:
- International Gas Turbine Institute
ISBN:
978-0-7918-4557-8
PROCEEDINGS PAPER
Isolating Effects of Area Ratio From Lobe Number for Turbofan Engine Exhaust Systems
Alex Wright,
Alex Wright
National Research Council of Canada, Ottawa, ON, Canada
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Ali Mahallati,
Ali Mahallati
National Research Council of Canada, Ottawa, ON, Canada
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Julio Militzer
Julio Militzer
Dalhousie University, Halifax, NS, Canada
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Alex Wright
National Research Council of Canada, Ottawa, ON, Canada
Ali Mahallati
National Research Council of Canada, Ottawa, ON, Canada
Julio Militzer
Dalhousie University, Halifax, NS, Canada
Paper No:
GT2014-27200, V01AT01A044; 16 pages
Published Online:
September 18, 2014
Citation
Wright, A, Mahallati, A, & Militzer, J. "Isolating Effects of Area Ratio From Lobe Number for Turbofan Engine Exhaust Systems." Proceedings of the ASME Turbo Expo 2014: Turbine Technical Conference and Exposition. Volume 1A: Aircraft Engine; Fans and Blowers. Düsseldorf, Germany. June 16–20, 2014. V01AT01A044. ASME. https://doi.org/10.1115/GT2014-27200
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