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.

Ultra-efficient propulsor with an augmentor fan circumscribing a turbofan

Abstract: An ultra-efficient “green” aircraft propulsor utilizing an augmentor fan is disclosed. A balanced design is provided combining a fuel efficient and low-noise high bypass ratio augmentor fan and a low-noise shrouded high bypass ratio turbofan. Three mass flow streams are utilized to reduce propulsor specific fuel consumption and increase performance relative to conventional turbofans. Methods are provided for optimization of fuel efficiency, power, and noise by varying mass flow ratios of the three mass flow streams. Methods are also provided for integration of external propellers into turbofan machinery.

Noise Reduction Technologies for Turbofan Engines

Abstract: Significant progress continues to be made with noise reduction for turbofan engines. NASA has conducted and sponsored research aimed at reducing noise from commercial aircraft. Since it takes many years for technologies to be developed and implemented, it is important to have aggressive technology goals that lead the target entry into service dates. Engine noise is one of the major contributors to the overall sound levels as aircraft operate near airports. Turbofan engines are commonly used on commercial transports due to their advantage for higher performance and lower noise. The noise reduction comes from combinations of changes to the engine cycle parameters and low noise design features. In this paper, an overview of major accomplishments from recent NASA research programs for engine noise will be given.

Thrust control apparatus for obtaining maximum thrust reversal in minimum time upon landing of an aircraft

Abstract: The thrust control apparatus of the present invention is employed on an aircraft having a wing and a turbofan engine mounted on a strut extending downwardly and forwardly from the wing. The thrust control apparatus includes (a) a rearwardly opening turbine engine nozzle for directing primary turbine exhaust effluent rearwardly from the engine, (b) a fan and an annular fan duct surrounding the forward portion of the turbine engine, (c) a primary fan air duct being coupled to the annular fan air duct, extending upwardly and rearwardly from the annular fan duct, and terminating in a separate rearwardly opening fan air nozzle for directing the secondary fan effluent rearwardly from the engine, and (d) a first auxiliary duct being coupled to the primary fan air duct, extending upwardly therefrom, and terminating in an upwardly opening auxiliary fan air nozzle for directing fan air flowing through the first auxiliary duct upwardly in front of the aircraft wing. During cruise operation, a valve associated with the coupling between the primary duct and the first auxiliary duct is positioned to close the first auxiliary duct, allowing all of the fan effluent to be exhausted through the fan air nozzle. Upon approach to landing, the valve associated with the coupling of the primary duct and the first auxiliary duct is adjusted to a position where it bifurcates the fan effluent between the primary duct and the first auxiliary duct. At the same time the engine throttle is advanced, calling for the turbofan engine to generate near maximum r.p.m. A plurality of vanes in the first auxiliary nozzle directs the fan effluent flowing through the first auxiliary duct upwardly and rearwardly over the upper airfoil surface of the wing. Upon touchdown of the aircraft on the landing field, the valve associated with the coupling between the primary duct and the first auxiliary duct closes the primary duct diverting the entire flow of fan effluent through the first auxiliary duct. At the same time the plurality of vanes in the first auxiliary nozzle are shifted to direct the fan effluent upwardly and forwardly relative to the engine and the wing, thus reversing the flow direction of the fan effluent and providing a reverse thrust component to brake the aircraft.

A Light Gradient Boosting Machine for Remainning Useful Life Estimation of Aircraft Engines

Abstract: The turbofan engine is a crucial component of the aircraft. In order to provide an appropriate maintenance for the turbofan engine to improve the reliability of the system, it is necessary to estimate the remaining useful life (RUL) of the engine. In this paper, a data-based RUL prediction method is proposed using the Light Gradient Boosting Machine (LightGBM). To capture more degradation information, the time window of row data and runtime of the turbofan engine are used as inputs to the proposed method after normalization. LightGBM works very well with these high-dimensional inputs and the model is easy to interpret. Moreover, LightGBM is insensitive to noise and can deal with redundant information in the time-window-size data, which facilitate the application of the proposed method to turbofan engines. In order to demonstrate the effectiveness of the proposed method, experiments are performed on C-MAPSS datasets provided by NASA, and the high prognostic accuracy is obtained. By comparing with the existing methods using the same dataset, the promising prospects of the proposed method in industry applications are illustrated.

Adaptive fan system for a variable cycle turbofan engine

Abstract: One embodiment of the present invention is a unique gas turbine engine. Another embodiment is a unique variable cycle gas turbine engine. Another embodiment is a unique adaptive fan system for a variable cycle turbofan engine having at least one turbine. Another embodiment is a unique method for operating a variable cycle gas turbine engine. Other embodiments include apparatuses, systems, devices, hardware, methods, and combinations for gas turbine engines and related systems.