Topic
Turbofan
About: Turbofan is a research topic. Over the lifetime, 4114 publications have been published within this topic receiving 39490 citations. The topic is also known as: fanjet & turbofan engine.
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09 Dec 2003TL;DR: In this paper, a method for detecting sensor faults in a turbofan engine is presented, which consists of an observer with integral action and an adaptive detection threshold, which is computed with the assumption of parametric uncertainty in the process model.
Abstract: A method for detecting sensor faults in a turbofan engine is presented. The proposed method consists of an observer with integral action and an adaptive detection threshold. The threshold is computed with the assumption of parametric uncertainty in the process model. Successful simulations with sensor data from an RM12 jet engine shows that the method is capable of detecting even a very small increase in sensor noise promptly without generating false alarms.
12 citations
01 Dec 1976
TL;DR: In this article, the static aerodynamic and acoustic characteristics of duct-burning turbofan (DBTF) exhaust nozzles are established and the inherent suppression characteristic of the unsuppressed coannular nozzle is related to the rapid mixing in the jet wake caused by the velocity profiles associated with the DBTF.
Abstract: The static aerodynamic and acoustic characteristics of duct-burning turbofan (DBTF) exhaust nozzles are established. Scale models, having a total area equivalent to a 0.127 m diameter convergent nozzle, simulating unsuppressed coannular nozzles and mechanically suppressed nozzles with and without ejectors (hardwall and acoustically treated) were tested in a quiescent environment. The ratio of fan to primary area was varied from 0.75 to 1.2. Far field acoustic data, perceived noise levels, and thrust measurements were obtained for 417 test conditions. Pressure ratios were varied from 1.3 to 4.1 in the fan stream and from 1.53 to 2.5 in the primary stream. Total temperature varied from 395 to 1090 K in both streams. Jet noise reductions relative to synthesized prediction from 8 PNdB (with the unsuppressed coannular nozzle) to 15 PNdB (with a mechanically suppressed configuration) were observed at conditions typical of engines being considered under the Advanced Supersonic Technology program. The inherent suppression characteristic of the unsuppressed coannular nozzle is related to the rapid mixing in the jet wake caused by the velocity profiles associated with the DBTF. Since this can be achieved without a mechanical suppressor, significant reductions in aircraft weight or noise footprint can be realized.
12 citations
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TL;DR: An advanced geared turbofan with year 2035 technology level assumptions was established and used for the hybridisation study, and the introduction of typical electrical power system performance characteristics and engine performance exchange rates is illustrated.
Abstract: An advanced geared turbofan with year 2035 technology level assumptions was established and used for the hybridisation study in this paper. By boosting the low-speed shaft of the turbofan with electrical power through the accessory gearbox, a parallel hybrid concept was set up. Focusing on the off-design performance of the hybridised gas turbine, electrical power input to the shaft, defined as positive hybridisation in this context, generally moves the compressor operation towards surge. On the other hand, the negative hybridisation, which is to reverse the power flow direction can improve the part-load operations of the turbofan and minimise the use of compressor handling bleeds. For the pre-defined mission given in the paper, negative hybridisation of descent, approach and landing, and taxi operations with 580 kW, 240 kW and 650 kW, respectively was found sufficient to keep a minimum compressor surge margin requirement without handling bleed.Looking at the hybridisation of key operating points, boosting the cruise operation of the baseline geared turbofan is, however, detrimental to the engine efficiency as it is pushing the cruise operation further away from the energy optimal design point. Without major modifications to the engine design, the benefit of the hybridisation appears primarily at the thermomechanical design point, the hot-day take-off. With the constraint of the turbine blade metal temperature in mind, a 500kW positive hybridisation at hot-day take-off gave cruise specific fuel consumption (SFC) reduction up to 0.5%, mainly because of reduced cooling flow requirement. Through the introduction of typical electrical power system performance characteristics and engine performance exchange rates, a first principles assessment is illustrated. By applying the strategies discussed in the paper, a 3% reduction in block fuel burn can be expected, if a higher power density electrical power system can be achieved.
12 citations
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12 Oct 2006
TL;DR: In this paper, a turbine engine with a spool supporting at least one of a compressor and a turbine is described, where the spool is arranged in a core nacelle (12) and the turbofan (20) is arranged upstream from the core nacelles.
Abstract: The invention relates to a turbine engine (10) that includes a spool (14) supporting at least one of a compressor (16) and a turbine (18). A turbofan (20) is coupled to the spool (14). The spool (14) is arranged in a core nacelle (12) and the turbofan (20) is arranged upstream from the core nacelle (12). A fan nacelle (34) surrounds the turbofan (20) and the core nacelle (12) and provides a bypass flow path (39). A structure (52) extends radially between the core (12) and fan (34) nacelles to support the core nacelle (12) relative to the fan nacelle (34). Surfaces (56) are supported relative to the fixed structure (52) and are moveable between closed and open positions to selectively obstruct bypass flow (13) through the bypass flow path (39), thereby changing the effective area of the exit nozzle (40). A change in the effective area of the nozzle exit (40) can be used to improve the efficiency and operation of the turbine engine.
12 citations
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01 Jan 1977TL;DR: In this article, the minimum time accelerations of aircraft turbofan engines are calculated using a piecewise linear engine model and an algorithm based on nonlinear programming, which allows such trajectories to be readily calculated on a digital computer with a minimal expenditure of computer time.
Abstract: Minimum time accelerations of aircraft turbofan engines are presented. The calculation of these accelerations was made by using a piecewise linear engine model, and an algorithm based on nonlinear programming. Use of this model and algorithm allows such trajectories to be readily calculated on a digital computer with a minimal expenditure of computer time.
12 citations