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.

Distributed Control of Turbofan Engines

Abstract: : The purpose of this paper is to develop control theoretic concepts for distributed control of gas turbine engines, and develop a dynamic engine model incorporating distributed components in compressor dynamics, engine cycles, and engine control. The latest results in distributed control combined with adaptive control theory are extended for turbofan engine distributed control. Concepts and architectures for distributed control are developed that create tangible benefits from the distribution of closed-loop feedback around the engine.

Nonvolatile particulate matter emissions of a business jet measured at ground level and estimated for cruising altitudes

Abstract: Business aviation is a relatively small but steadily growing and little investigated emission source. Regarding emissions, aircraft turbine engines rated at and below 26.7 kN thrust are certified only for visible smoke and are excluded from the nonvolatile particulate matter (nvPM) standard. Here, we report nvPM emission characteristics of a widely used small turbofan engine determined in a ground test of a Dassault Falcon 900EX business jet. These are the first reported nvPM emissions of a small in-production turbofan engine determined with a standardized measurement system used for emissions certification of large turbofan engines. The ground-level measurements together with a detailed engine performance model were used to predict emissions at cruising altitudes. The measured nvPM emission characteristics strongly depended on engine thrust. The geometric mean diameter increased from 17 nm at idle to 45 nm at take-off. The nvPM emission indices peaked at low thrust levels (7 and 40% take-off thrust in terms of nvPM number and mass, respectively). A comparison with a commercial airliner shows that a business jet may produce higher nvPM emissions from flight missions as well as from landing and take-off operations. This study will aid the development of emission inventories for small aircraft turbine engines and future emission standards.

Air-cooled oil cooler for turbofan engine

Abstract: A turbofan gas turbine engine comprises a nacelle cowl and a core engine. A bypass duct is between an outer surface of a casing of the core engine, and an inner surface of the nacelle cowl. An air channel is in the nacelle cowl, an inlet and an outlet of the air channel being in an outer surface of the nacelle cowl. An oil cooler has at least one oil passage for oil circulation, the air cooler having a first heat exchange surface in the air channel exposed to air circulating in the air channel, the air channel having a second heat exchange surface in the bypass duct exposed to air circulating in the bypass duct. A method for cooling oil in a turbofan gas turbine engine is also provided.

Method and apparatus for quieting a turbojet engine

Abstract: A noise suppressor for attachment to the aft end of an existing turbojet engine. The noise suppressor includes a free-running turbofan wheel which includes a turbine section mounted for reaction to the exhaust gas from the jet engine, and a concentric outer fan section extending within an air duct concentric with the turbofan wheel. The jet exhaust from normal operation of the jet engine spins the free-running turbofan wheel, and the fan section of that wheel produces a flow of compressed air through the duct to surround and mix with the jet exhaust, thereby reducing the noise emission of the jet engine. A thrust reverser and an afterburner are optional for use with the noise suppressor.