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.

Geared counter-rotating gas turbofan engine

Abstract: A gas turbine engine includes a gear system driven by a first and second counter rotating low pressure shaft and a fan driven by the gear system.

Exhaust nozzle control and core engine fuel control for turbofan engine

Abstract: An exhaust nozzle control and core engine fuel control for a turbofan engine serving to optimize thrust during steady state and transient operation modes of a turbofan engine of the mixed flow type by adjusting or trimming the exhaust nozzle area as a function of fan pressure ratio and fan rotor speed and by adjusting or trimming the core engine fuel flow as a function of fan rotor speed and or turbine inlet temperature. The control serves to enhance stability by assuring airflow in the engine and its inlet is within a given value avoiding inlet buzz and high distortion to the engine and avoiding even transient operation in conditions that might cause compressor flow instability or stall. Fuel flow is adjusted or trimmed as a function of fan rotor speed or turbine inlet temperature limits depending on which is calling for the least amount of fuel.

Propulsion system for a V/STOL airplane

Abstract: A propulsion system for an airplane to permit it to achieve vertical and/or short take-offs and landings. The propulsion system is integrated into a wing/nacelle unit and includes a thrust vectoring system. A separate flow turbofan engine is mounted in each wing/nacelle unit. A system of three flaps is located at the rear of each wing/nacelle unit for deflecting the turbofan engine exhaust downward, rearward, or any angle in between. These three flaps are arranged to provide a main thrust nozzle in the horizontal flight position without any additional flaps between them. One flap is located at the wing/nacelle upper surface trailing edge. Two slots are provided at the leading edge of this flap. The upper forward most slot is provided as an exit nozzle for the engine turbine exhaust, which is shrouded from the fan exhaust. The second of these two slots removes a portion of the high energy fan exhaust from the fan discharge duct and ejects it over the flap upper surface. The other two flaps are positioned such that, in the horizontal position they are both aligned with the wing/nacelle lower surface and in the vertical position, one is aligned with the wing/nacelle lower surface and the other is aligned with the wing/nacelle upper surface. When the flaps are in the vertical position, the aft most slot in the upper flap and a slot formed between the upper flap and the lower aft flap provide a means of improving the turning efficiency of the fan exhaust stream.

Turbofan engine bypass and exhaust system

Abstract: A turbofan engine bypass and exhaust system has a double-hoop configuration in which a fan exhaust passageway comprises shells of a constant circular contour to resolve air pressure induced stresses and increase in bypass passageway area asymmetrically in the horizontal direction without substantially increasing the overall engine height.

Aerodynamic Design of a Dual-Flow Mach 7 Hypersonic Inlet System for a Turbine-Based Combined-Cycle Hypersonic Propulsion System

Abstract: A new hypersonic inlet for a turbine-based combined-cycle (TBCC) engine has been designed. This split-flow inlet is designed to provide flow to an over-under propulsion system with turbofan and dual-mode scramjet engines for flight from takeoff to Mach 7. It utilizes a variable-geometry ramp, high-speed cowl lip rotation, and a rotating low-speed cowl that serves as a splitter to divide the flow between the low-speed turbofan and the high-speed scramjet and to isolate the turbofan at high Mach numbers. The low-speed inlet was designed for Mach 4, the maximum mode transition Mach number. Integration of the Mach 4 inlet into the Mach 7 inlet imposed significant constraints on the low-speed inlet design, including a large amount of internal compression. The inlet design was used to develop mechanical designs for two inlet mode transition test models: small-scale (IMX) and large-scale (LIMX) research models. The large-scale model is designed to facilitate multi-phase testing including inlet mode transition and inlet performance assessment, controls development, and integrated systems testing with turbofan and scramjet engines.