A Performance Study of a Super-cruise Engine with Isothermal Combustion inside the Turbine

dc.contributor.authorChiu, Ya-Tienen
dc.contributor.committeechairKing, Peter S.en
dc.contributor.committeememberSexton, Michael R.en
dc.contributor.committeememberThole, Karen A.en
dc.contributor.committeememberVandsburger, Urien
dc.contributor.committeememberO'Brien, Walter F. Jr.en
dc.contributor.departmentMechanical Engineeringen
dc.date.accessioned2014-03-14T20:21:00Zen
dc.date.adate2005-01-05en
dc.date.available2014-03-14T20:21:00Zen
dc.date.issued2004-12-09en
dc.date.rdate2005-01-05en
dc.date.sdate2004-12-21en
dc.description.abstractCurrent thinking on the best propulsion system for a next-generation supersonic cruising (Mach 2 to Mach 4) aircraft is a mixed-flow turbofan engine with afterburner. This study investigates the performance increase of a turbofan engine through the use of isothermal combustion inside the high-pressure turbine (High-Pressure Turburner, HPTB) as an alternative form of thrust augmentation. A cycle analysis computer program is developed for accurate prediction of the engine performance and a supersonic transport cruising at Mach 2 at 60,000 ft is used to demonstrate the merit of using a turburner. When assuming no increase in turbine cooling flow is needed, the engine with HPTB could provide either 7.7% increase in cruise range or a 41% reduction in engine mass flow when compared to a traditional turbofan engine providing the sane thrust. If the required cooling flow in the turbine is almost doubled, the new engine with HPTB could still provide a 4.6% increase in range or 33% reduction in engine mass flow. In fact, the results also show that the degradation of engine performance because of increased cooling flow in a turburner is less than half of the degradation of engine performance because of increased cooling flow in a regular turbine. Therefore, a turbofan engine with HPTB will still easily out-perform a traditional turbofan when even more cooling than currently assumed is introduced. Closer examination of the simulation results in off-design regimes also shows that the new engine not only satisfies the thrust and efficiency requirement at the design cruise point, but also provides enough thrust and comparable or better efficiency in all other flight regimes such as transonic acceleration and take-off. Another finding is that the off-design bypass ratio of the new engine increases slower than a regular turbofan as the aircraft flies higher and faster. This behavior enables the new engine to maintain higher thrust over a larger flight envelope, crucial in developing faster air-breathing aircraft for the future. As a result, an engine with HPTB provides significant benefit both at the design point and in the off-design regimes, allowing smaller and more efficient engines for supersonic aircraft to be realized.en
dc.description.degreePh. D.en
dc.identifier.otheretd-12212004-091959en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-12212004-091959/en
dc.identifier.urihttp://hdl.handle.net/10919/30202en
dc.publisherVirginia Techen
dc.relation.haspartMathCAD.zipen
dc.relation.haspartReadme.txten
dc.relation.haspartDissertation.pdfen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectSuper-cruise Engineen
dc.subjectTurbine Coolingen
dc.subjectIsothermal Combustionen
dc.subjectIdeal Gas Mixtureen
dc.subjectCycle Analysisen
dc.subjectOff-design Performanceen
dc.titleA Performance Study of a Super-cruise Engine with Isothermal Combustion inside the Turbineen
dc.typeDissertationen
thesis.degree.disciplineMechanical Engineeringen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.leveldoctoralen
thesis.degree.namePh. D.en

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