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Subsonic Performance of Ejector Systems

Weil, Samuel P
http://rave.ohiolink.edu/etdc/view?acc_num=ucin1428048770

Abstract Details

2015, MS, University of Cincinnati, Engineering and Applied Science: Aerospace Engineering.
Combined cycle engines combining scramjets with turbo jets or rockets can provide efficient hypersonic flight. Ejectors have the potential to increase the thrust and efficiency of combined cycle engines near static conditions. A computer code was developed to support the design of a small-scale, turbine-based combined cycle demonstrator with an ejector, built around a commercially available turbojet engine. This code was used to analyze the performance of an ejector system built around a micro-turbojet. With the use of a simple ejector, net thrust increases as large as 20% over the base engine were predicted. Additionally the specific fuel consumption was lowered by 10%. Increasing the secondary to primary area ratio of the ejector lead to significant improvements in static thrust, specific fuel consumption (SFC), and propulsive efficiency. Further ejector performance improvements can be achieved by using a diffuser. Ejector performance drops off rapidly with increasing Mach number. The ejector has lower thrust and higher SFC than the turbojet core at Mach numbers above 0.2. When the nozzle chokes a significant drop in ejector performance is seen. When a diffuser is used, higher Mach numbers lead to choking in the mixer and a shock in the nozzle causing a significant decrease in ejector performance. Evaluation of different turbo jets s hows that ejector performance depends significantly on the properties of the turbojet. Static thrust and SFC improvements can be achieved with increasing ejector area for all engines, but size of increase and change in performance at higher Mach numbers depend heavily on the turbojet. The use of an ejector in a turbine based combined cycle configuration also increases performance at static conditions with a thrust increase of 5% and SFC decrease of 5% for the tested configuration.
Mark Turner, Sc.D. (Committee Chair)
Shaaban Abdallah, Ph.D. (Committee Member)
Paul Orkwis, Ph.D. (Committee Member)
93 p.
Aerospace Materials
Propulsion; Turbine Based Combined Cycle; Ejector

Recommended Citations

Citations

  • Weil, S. P. (2015). Subsonic Performance of Ejector Systems [Master's thesis, University of Cincinnati]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1428048770

    APA Style (7th edition)

  • Weil, Samuel. Subsonic Performance of Ejector Systems. 2015. University of Cincinnati, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ucin1428048770.

    MLA Style (8th edition)

  • Weil, Samuel. "Subsonic Performance of Ejector Systems." Master's thesis, University of Cincinnati, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1428048770

    Chicago Manual of Style (17th edition)

ucin1428048770
359
© 2015, all rights reserved.
This open access ETD is published by University of Cincinnati and OhioLINK.