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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01 Jan 2017
TL;DR: In this article, the authors propose a set of theoretical models to predict, during the conceptual design phase, the sound emitted by the fan stage of an aero-engine, covering a range of discipilnes that span between aerodynamics and acoustics.
Abstract: This thesis proposes a set of theoretical models to predict, during the conceptual design Phase, the sound emitted by the fan stage of an aero-engine. The models are analytical or semi-analytical, and cover a range of discipilnes that span between aerodynamics and acoustics. Various fan architectures, such as the conventional ducted turbofan, the ducted contra-rotating fan and the contra-rotating open Rotors, are addressed on a common basis.
This thesis presents the theoretical fundament of the fan noise prediction program PropNoise.
19 citations
25 Jul 2016
TL;DR: In this paper, the application of a model-based engine control (MBEC) methodology featuring a self-tuning on-board model for an aircraft turbofan engine simulation is discussed.
Abstract: This paper covers the application of a model-based engine control (MBEC) methodology featuring a self tuning on-board model for an aircraft turbofan engine simulation. The nonlinear engine model is capable of modeling realistic engine performance, allowing for a verification of the advanced control methodology over a wide range of operating points and life cycle conditions. The on-board model is a piece-wise linear model derived from the nonlinear engine model and updated using an optimal tuner Kalman Filter estimation routine, which enables the on-board model to self-tune to account for engine performance variations. MBEC is used here to show how advanced control architectures can improve efficiency during the design phase of a turbofan engine by reducing conservative operability margins. The operability margins that can be reduced, such as stall margin, can expand the engine design space and offer potential for efficiency improvements. Application of MBEC architecture to a nonlinear engine simulation is shown to reduce the thrust specific fuel consumption by approximately 1% over the baseline design, while maintaining safe operation of the engine across the flight envelope.
19 citations
Patent•
26 Jul 2011TL;DR: In this article, a boundary layer ejector fluidically connects boundary layer bleed slots from an external surface of an aircraft to reduce aircraft/nacelle/pylon drag, reduce jet noise and decrease thrust specific fuel consumption.
Abstract: The present inventions include a boundary layer ejector fluidically connecting boundary layer bleed slots from an external surface of an aircraft to reduce aircraft/nacelle/pylon drag, reduce jet noise and decrease thrust specific fuel consumption. In one embodiment a boundary layer withdrawn through the boundary layer bleed slots is entrained with an exhaust flow of a gas turbine engine. In another embodiment a boundary layer withdrawn through the boundary layer bleed slots is entrained with a flow stream internal to the gas turbine engine, such as a fan stream of a turbofan. Members can be provided near an outlet of a passageway conveying the withdrawn boundary layer air to locally reduce the pressure of the fluid in which the withdrawn boundary layer air is to be entrained. A lobed mixer can be used in some embodiments to effect mixing between the boundary layer and a primary fluid of the ejector.
19 citations
Patent•
12 Oct 2006TL;DR: In this paper, a turbofan engine includes a fan variable area nozzle, which includes a louver system having a multiple of slats generally transverse to the engine axis.
Abstract: A turbofan engine includes a fan variable area nozzle, which includes a louver system having a multiple of slats generally transverse to the engine axis. Each of the louver slats are pivotally mounted to the fan nacelle to vary the effective area of the fan nozzle exit area and permit efficient engine operation at predefined pressure ratios.
19 citations
TL;DR: In this article, an iterative finite element integral technique is used to predict the sound field radiated from the JT15D turbofan inlet, which is divided into two regions: the sound fields within and near the inlet which are computed using the finite element method and the radiation field beyond the INlet which is calculated using an integral solution technique.
Abstract: An iterative finite element integral technique is used to predict the sound field radiated from the JT15D turbofan inlet. The sound field is divided into two regions: the sound field within and near the inlet which is computed using the finite element method and the radiation field beyond the inlet which is calculated using an integral solution technique. The velocity potential formulation of the acoustic wave equation was employed in the program. For some single mode JT15D data, the theory and experiment are in good agreement for the far field radiation pattern as well as suppressor attenuation. Also, the computer program is used to simulate flight effects that cannot be performed on a ground static test stand.
19 citations