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Design and control of a variable geometry turbofan with and independently modulated third stream

Simmons, Ronald Jay
http://rave.ohiolink.edu/etdc/view?acc_num=osu1243607482

Abstract Details

2009, Doctor of Philosophy, Ohio State University, Aeronautical and Astronautical Engineering.
Emerging 21st century military missions task engines to deliver the fuel efficiency of a high bypass turbofan while retaining the ability to produce the high specific thrust of a low bypass turbofan. This study explores the possibility of satisfying such competing demands by adding a second independently modulated bypass stream to the basic turbofan architecture. This third stream can be used for a variety of purposes including: providing a cool heat sink for dissipating aircraft heat loads, cooling turbine cooling air, and providing a readily available stream of constant pressure ratio air for lift augmentation. Furthermore, by modulating airflow to the second and third streams, it is possible to continuously match the engine’s airflow demand to the inlet’s airflow supply thereby reducing spillage and increasing propulsive efficiency. This research begins with a historical perspective of variable cycle engines and shows a logical progression to proposed architectures. Then a novel method for investigating optimal performance is presented which determines most favorable on design variable geometry settings, most beneficial moment to terminate flow holding, and an optimal scheduling of variable features for fuel efficient off design operation. Mission analysis conducted across the three candidate missions verifies that these three stream variable cycles can deliver fuel savings in excess of 30% relative to a year 2000 reference turbofan. This research concludes by evaluating the relative impact of each variable technology on the performance of adaptive engine architectures. The most promising technologies include modulated turbine cooling air, variable high pressure turbine inlet area and variable third stream nozzle throat area. With just these few features it is possible to obtain nearly optimal performance, including 90% or more of the potential fuel savings, with far fewer variable features than are available in the study engine. It is abundantly clear that three stream variable architectures can significantly outperform existing two stream turbofans in both fuel efficiency and at the vehicle system level with only a modest increase in complexity and weight. Such engine architectures should be strongly considered for future military applications.
Meyer Benzakein (Advisor)
Richard Bodonyi (Committee Member)
Jefrey Bons (Committee Member)
Jen-Ping Chen (Committee Member)
Nicholas Kuprowicz (Committee Member)
124 p.
Engineering
variable geometry turbofan; double bypass; three stream turbofan

Recommended Citations

Citations

  • Simmons, R. J. (2009). Design and control of a variable geometry turbofan with and independently modulated third stream [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1243607482

    APA Style (7th edition)

  • Simmons, Ronald. Design and control of a variable geometry turbofan with and independently modulated third stream. 2009. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1243607482.

    MLA Style (8th edition)

  • Simmons, Ronald. "Design and control of a variable geometry turbofan with and independently modulated third stream." Doctoral dissertation, Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1243607482

    Chicago Manual of Style (17th edition)

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© 2009, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.