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Showing papers on "Turbofan published in 1991"


Patent
22 Feb 1991
TL;DR: In this article, a propulsion system for a V/STOL type aircraft is described, which comprises a turbofan engine including a fan section (46), compressor section (65), combustion section (74), turbine section (58), and nozzle section (34).
Abstract: The invention is a propulsion system for a V/STOL type aircraft. In detail, the invention comprises a turbofan engine (31) including a fan section (46), compressor section (65), combustion section (74), turbine section (58) and nozzle section (34). The turbine section (58) comprises a low-pressure turbine portion (56) coupled to and driving the fan section (46) and a high-pressure turbine portion (68) coupled to and driving the compressor section (65). A lift fan (36) is coupled to the fan section (46) by means of a drive shaft (52). A clutch (108) is incorporated for de-coupling the lift fan (36) from the fan section (46). A mechanism (80) is incorporated for extracting additional power from the low-pressure turbine portion (56) of the turbine section (58) to drive the lift fan (36) that augments the basic engine thrust for V/STOL operation.

93 citations


Patent
26 Sep 1991
TL;DR: In this article, a structure for removing bending caused by an inlet lift load in the engine core of an aircraft having a support frame which is attached to a frame mount which connects to the pylon floor is presented.
Abstract: A structure for removing bending caused by an inlet lift load in the engine core of an aircraft having a support frame which is attached to a frame mount which connects to the pylon floor The frame mount is located between a forward mount and a rear mount and to the front of the engine core As a result of the frame mount, the moment created by the inlet lift load is not reacted through the engine core so engine performance is not affected

44 citations


Journal ArticleDOI
TL;DR: In this paper, an extensive analytical and experimental program has been undertaken to investigate the Foreign Object Damage resistance capabilities of external components for small gas turbofan engines, and a transient nonlinear impact analysis has been used to predict the structural response of fan blades under bird ingestion conditions.
Abstract: An extensive analytical and experimental program has been undertaken to investigate the Foreign Object Damage resistance capabilities of external components for small gas turbofan engines. A transient nonlinear impact analysis has been used to predict the structural response of fan blades under bird ingestion conditions. This analysis is based on finite elements, a three-dimensional bird load model, and an interactive structure-to-bird contact algorithm. Experiments were designed and carried out to record large blade deformations during bird impact, and were used to validate and calibrate the analytical models. The analytical models and testing program are described, and dominant fan blade response and failure modes are presented. Predicted results demonstrate good correlation with tests. Analysis application to fan blade design and other engine components is recommended.

35 citations


01 Feb 1991
TL;DR: In this paper, the effects of the seventh-stage compressor bleed on the performance of the F100 afterburning turbofan engine were investigated for intermediate, partial, and maximum afterburning for Mach numbers between 0.6 and 2.2 and for altitudes of 30,000, 40,000 and 50,000 ft.
Abstract: A study was conducted to determine the effects of seventh-stage compressor bleed on the performance of the F100 afterburning turbofan engine. The effects of bleed on thrust, specific fuel consumption, fan turbine inlet temperature, bleed total pressure, and bleed total temperature were obtained from the engine manufacturer's status deck computer simulation. These effects were determined for power settings of intermediate, partial afterburning, and maximum afterburning for Mach numbers between 0.6 and 2.2 and for altitudes of 30,000, 40,000, and 50,000 ft. It was found that thrust loss and specific fuel consumption increase were approximately linear functions of bleed flow and, based on a percent-thrust change basis, were approximately independent of power setting.

23 citations


01 Jun 1991
TL;DR: In this article, a Kalman filter design is presented for estimating two performance parameters that account for engine deterioration: high and low pressure turbine delta efficiencies, which can be estimated with an accuracy of + or - 0.25 percent.
Abstract: Deterioration of engine components may cause off-normal engine operation. The result is an unecessary loss of performance, because the fixed schedules are designed to accommodate a wide range of engine health. These fixed control schedules may not be optimal for a deteriorated engine. This problem may be solved by including a measure of deterioration in determining the control variables. These engine deterioration parameters usually cannot be measured directly but can be estimated. A Kalman filter design is presented for estimating two performance parameters that account for engine deterioration: high and low pressure turbine delta efficiencies. The delta efficiency parameters model variations of the high and low pressure turbine efficiencies from nominal values. The filter has a design condition of Mach 0.90, 30,000 ft altitude, and 47 deg power level angle (PLA). It was evaluated using a nonlinear simulation of the F100 engine model derivative (EMD) engine, at the design Mach number and altitude over a PLA range of 43 to 55 deg. It was found that known high pressure turbine delta efficiencies of -2.5 percent and low pressure turbine delta efficiencies of -1.0 percent can be estimated with an accuracy of + or - 0.25 percent efficiency with a Kalman filter. If both the high and low pressure turbine are deteriorated, the delta efficiencies of -2.5 percent to both turbines can be estimated with the same accuracy.

20 citations


Proceedings ArticleDOI
01 Jun 1991
TL;DR: In this article, a performance seeking control (PSC) algorithm has undergone initial flight test evaluation in subsonic operation of a PW 1128 engined F-15, and the flight test results have verified a thrust specific fuel consumption reduction of 1 pct, up to 100 R decreases in FTIT, and increases of as much as 12 pct in maximum thrust.
Abstract: A performance seeking control (PSC) algorithm has undergone initial flight test evaluation in subsonic operation of a PW 1128 engined F-15. This algorithm is designed to optimize the quasi-steady performance of an engine for three primary modes: (1) minimum fuel consumption; (2) minimum fan turbine inlet temperature (FTIT); and (3) maximum thrust. The flight test results have verified a thrust specific fuel consumption reduction of 1 pct., up to 100 R decreases in FTIT, and increases of as much as 12 pct. in maximum thrust. PSC technology promises to be of value in next generation tactical and transport aircraft.

20 citations


Journal ArticleDOI
TL;DR: In this article, the results of a full-scale engine demonstration of a sensor failure detection algorithm are presented, which detects, isolates, and accommodates sensor failures using analytical redundancy.
Abstract: In the paper, the results of a full-scale engine demonstration of a sensor failure detection algorithm are presented. The algorithm detects, isolates, and accommodates sensor failures using analytical redundancy. The experimental hardware, including the F100 engine, is described. Demonstration results were obtained over a large portion of a typical flight envelope for the F100 engine. They include both subsonic and supersonic conditions at both medium and full, nonafter burning, power. Estimated accuracy, minimum detectable levels of sensor failures, and failure accommodation performance for an F100 turbofan engine control system are discussed.

19 citations


01 Jan 1991
TL;DR: The potential to simulate the entire engine operation on a computer without the aid of data is demonstrated by numerically generating "performance maps" for a fan component using two flow models of varying fidelity.
Abstract: In this paper, a heterogeneous propulsion system simulation method is presented. The method is based on the formulation of a cycle model of a gas turbine engine. The model includes the nonlinear characteristics of the engine components via use of empirical data. The potential to simulate the entire engine operation on a computer without the aid of data is demonstrated by numerically generating "performance maps" for a fan component using two flow models of varying fidelity. The suitability of the fan models were evaluated by comparing the computed performance with experimental data. A discussion of the potential benefits and/or difficulties in connecting simulations solutions of differing fidelity is given.

18 citations


PatentDOI
TL;DR: A noise suppressor for attachment to the aft end of an existing turbojet engine is described in this paper, which includes a free-running turbofan wheel and a turbine section mounted for reaction to the exhaust gas from the jet 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.

16 citations


Proceedings ArticleDOI
03 Jun 1991
TL;DR: In this paper, a variable cycle jet engine for a supersonic STOVL aircraft is described, which is the selective bleed turbofan, a two shaft three compressor engine.
Abstract: A new concept in aircraft propulsion is described in this paper. A variable cycle jet engine is being investigated for a supersonic STOVL aircraft. The engine is the selective bleed turbofan, a two shaft three compressor engine. At low flight speeds this engine operates as a medium bypass turbofan, and for the supersonic cruise condition it operates as a low bypass ratio turbofan in the dry mode.In this paper, the performance of the engine and some of the components is analysed. Off-design engine performance characteristics are explained, compressor running lines are shown, and variable geometry requirements are described.The performance analysis shows that fuel savings are significant, thus reducing aircraft take-off weight. The major advantage of this engine is that all the components are employed all the time, for all operating modes, thus incurring low weight penalties.Copyright © 1991 by ASME

14 citations


Journal ArticleDOI
S. F. Powel1
TL;DR: In this paper, the overall design concept of the F404 afterburning turbofan engine is reviewed together with some of the lessons learned from over 2 million flight hours in service.
Abstract: In this paper the overall design concept of the F404 afterburning turbofan engine is reviewed together with some of the lessons learned from over 2 million flight hours in service. GE Aircraft Engines' derivative and growth plans for the F404 family are then reviewed including the Building Block component development approach. Examples of advanced technologies under development for introduction into new F404 derivative engine models are presented in the areas of materials, digital and fiber optic controls systems, and vectoring exhaust nozzles. The design concept and details of the F404-GE-402, F412-GE-400, and other derivative engines under full-scale development are described. Studies for future growth variants and the benefits of the F404 derivative approach to development of afterburning engines in the 18,000-24,000 lb (80--107 kN) thrust class and non- afterburning engines in the 12,000--19,000 lb (53--85 kN) class are discussed.

Patent
24 Sep 1991
TL;DR: The turbo-fan engine has a fan rotor, a booster compressor located downstream of the fan rotor and a drive section with a core compressor and turbine as mentioned in this paper, and a working turbine is connected to the rotor via a drive shaft.
Abstract: The turbo-fan engine has a fan rotor, a booster compressor located downstream of the fan rotor, and a drive section with a core compressor and turbine. A working turbine is connected to the fan rotor via a drive shaft. The booster compressor is formed as a precompressor stage (16), of the core compressor (9), and is removably connected to it. The fan engine (1) has two fan rotors (3, 4). These are driven via two coaxial drive shafts (5a, b) by an opposite working turbine (13). ADVANTAGE - Flexible variation of pressure ratio.

Proceedings ArticleDOI
03 Jun 1991
TL;DR: In this article, a mathematical model by which the off-design performance of turbofans can be predicted, knowing just the design point parameters is described, making the use of compressor and turbine maps redundant.
Abstract: This paper describes a mathematical model by which the off-design performance of turbofans can be predicted, knowing just the design point parameters. Off-design performance has been estimated by using gas-dynamic properties of the exhaust nozzles, which regulate the aerothermodynamic behaviour of the upstream components. Approximate overall performance of a turbofan at typical cruising conditions can be estimated, making the use of compressor and turbine maps redundant.Copyright © 1991 by ASME

Patent
20 May 1991
TL;DR: In the non-augmented mode the flow for combustion is stopped and the cooling air is used to cool the tail cone and exit guide vanes as mentioned in this paper, thereby reducing infrared radiation.
Abstract: A turbofan engine uses fan air to cool bounding surfaces of the exhaust duct at all times. A portion of the fan air flow is used for augmentor combustion in the augmentation mode. In the non-augmented mode the flow for combustion is stopped and the cooling air is used to cool the tail cone and exit guide vanes. Infrared radiation is thereby reduced when non-augmented.

Proceedings ArticleDOI
07 Jan 1991
TL;DR: In this article, a combined analytical and experimental study was conducted to establish an analytical procedure for optimizing the design of forced mixers for application to high bypass ratio turbofan engines.
Abstract: A combined analytical and experimental study was conducted to establish an analytical procedure for optimizing the design of forced mixers for application to high bypass ratio turbofan engines. This two part study involved the application of a fully three-dimensional viscous procedure to a series of mixer configurations, followed by an experimental program to validate the analytical procedure. The viscous analysis used for this study involved combining two robust and versatile codes: PARC-3D, a flow solver, with INGRID-3D grid generation code. Comparison between the Navier-Stokes solution and detailed experimental measurements were made for five different mixer configuration. Both global performance parameters and detailed temperature distributions were compared. Predicted results were found to be in excellent agreement with test data. Gross thrust coefficient, defined in Section 4 Specific heat at constant pressure Thrust coefficient, defined in Section4 Diameter of mixing duct at lobe exit plane Gross thrust Length of mixing duct b s s flow rate Pressure Total pressure Radius of shroud Total temperature Velocity Radial distance measured from center body surf ace

Proceedings ArticleDOI
01 Sep 1991
TL;DR: In this article, a comparison of the turbine bypass engine and the mixed flow turbofan for a Mach 2.4 cruise application is presented, and a parametric assessment is conducted for each cycle.
Abstract: A comparison of the turbine bypass engine and the mixed flow turbofan for a Mach 2.4 cruise application is presented. A parametric assessment is conducted for each cycle. Parameters that are investigated for the turbine bypass engine include design bypass, combustor exit temperature, and overall pressure ratio. Parameters that are investigated for the mixed flow turbofan include fan pressure ratio, mixer design pressure ratio, and combustor exit temperature. The engines are analyzed for a 5000-nautical-mile, all supersonic cruise mission to determine the aircraft takeoff gross weights. The effects of takeoff noise, cruise emissions, the addition of subsonic cruise legs, and constrained supersonic cruise altitudes are also evaluated.

01 Sep 1991
TL;DR: In this article, a procedure for generating three-dimensional grids for advanced turbofan engine fan section geometries is presented, which is consistent with aerodynamic analyses utilizing the average-passage equation system developed by Dr. John Adamczyk.
Abstract: A procedure is studied for generating three-dimensional grids for advanced turbofan engine fan section geometries. The procedure constructs a discrete mesh about engine sections containing the fan stage, an arbitrary number of axisymmetric radial flow splitters, a booster stage, and a bifurcated core/bypass flow duct with guide vanes. The mesh is an h-type grid system, the points being distributed with a transfinite interpolation scheme with axial and radial spacing being user specified. Elliptic smoothing of the grid in the meridional plane is a post-process option. The grid generation scheme is consistent with aerodynamic analyses utilizing the average-passage equation system developed by Dr. John Adamczyk of NASA Lewis. This flow solution scheme requires a series of blade specific grids each having a common axisymmetric mesh, but varying in the circumferential direction according to the geometry of the specific blade row.

Proceedings ArticleDOI
01 Sep 1991
TL;DR: In this paper, the potential application of hybrid laminar flow to modern commercial transport aircraft was successfully flight tested on a Boeing 757 aircraft in a limited demonstration, in which only part of the upper surface of the swept wing was designed for the attainment of LFL flow, significant local drag reduction was measured.
Abstract: Recently, the concept of the application of hybrid laminar flow to modern commercial transport aircraft was successfully flight tested on a Boeing 757 aircraft In this limited demonstration, in which only part of the upper surface of the swept wing was designed for the attainment of laminar flow, significant local drag reduction was measured This paper addresses the potential application of this technology to laminarize the external surface of large, modern turbofan engine nacelles which may comprise as much as 5-10 percent of the total wetted area of future commercial transports A hybrid-laminar-flow-control (HLFC) pressure distribution is specified and the corresponding nacelle geometry is computed utilizing a predictor/corrector design method Linear stability calculations are conducted to provide predictions of the extent of the laminar boundary layer Performance studies are presented to determine potential benefits in terms of reduced fuel consumption

Journal ArticleDOI
TL;DR: In this paper, a new concept of combined cycle propulsion system is proposed, in which a turbojet (or turbofan) type engine provides compressed air as part or the whole oxidizer to the rocket engine at takeoff and part of the acceleration and climb.
Abstract: A new concept of combined cycle propulsion system is proposed. In the proposed system, a turbojet (or turbofan) type engine provides compressed air as part or the whole oxidizer to the rocket engine at takeoff and part of the acceleration and climb. At the same time, the turbo-engine provides a portion of the thrust. The system performance shows little sensitivity to rocket chamber pressure, shows comparable performance to turbojet, and is capable to shifting to pure rocket mode at any desired point in the flight trajectory.

Journal ArticleDOI
TL;DR: The upper surface blowing STOL aircraft named ASKA was developed and flight tested by the National Aerospace Laboratory of Japan between 1977-1989 as mentioned in this paper, which was a conversion of the Kawasaki C-1 medium transport, with four newly developed FJR710/600S turbofan engines on the wing.
Abstract: The Upper Surface Blowing STOL aircraft named ASKA was developed and flight tested by the National Aerospace Laboratory of Japan between 1977-1989. The aircraft was a conversion of the Kawasaki C-1 medium transport, with four newly developed FJR710/600S turbofan engines on the wing. The short takeoff and landing performance, including the stability and control augmentation system and boundary-layer control, was intensively examined by the flight test. Flight-test data were obtained at altitude and converted to the standard sea level conditions to compare with the design data. From the viewpoint of the lift-and-drag and related performances, the design STOL capability was proven by the flight-test program.

25 Mar 1991
TL;DR: In this paper, the authors describe the design of a multivariable control for an aeroplane turbofan engine based on working line control, which is illustrated by means of engine test results, and the emphasis is on the control structure, which must include the essential features of a complete flightworthy system, such as all the necessary limiters and a pilot's lever-driven range control, using scheduled gains capable of accommodating parameter variations across the flight envelope.
Abstract: This paper describes the design of a multivariable control for an aeroplane turbofan engine based on working line control. The method starts with the identified engine. Controller performance is illustrated by means of engine test results. The emphasis is on the control structure, which must include the essential features of a complete flight-worthy system, such as all the necessary limiters and a pilot's lever-driven range control, using scheduled gains capable of accommodating parameter variations across the flight envelope. Less importance is attached, at this stage, to the system response attributable to the design of the individual multivariable compensators. In the first instance they were designed as simple P+I controllers. Any changes in the design of the individual compensators can be accommodated within the overall scheme.< >

Journal ArticleDOI
TL;DR: In this article, pylon shaping and nacelle bypass ratio studies for turbofan transports, nacelles and wing contouring, and propeller location effects for turboprop transports, empennage effects, and thrust vectoring for high-performance aircraft were conducted in NASA Langley's 16-Foot Transonic Tunnel at Mach numbers up to 1.20.
Abstract: A significant level of research is ongoing at NASA's Langley Research center on integrating the propulsion system with the aircraft. This program has included nacelle/pylon/wing integration for turbofan transports, propeller/nacelle/wing integration for turboprop transports, and nozzle/afterbody/empennage integration for high-performance aircraft. The studies included in this paper focus more specifically on pylon shaping and nacelle bypass ratio studies for turbofan transports, nacelle and wing contouring, and propeller location effects for turboprop transports, empennage effects, and thrust vectoring for high-performance aircraft. The studies were primarily conducted in NASA Langley's 16-Foot Transonic Tunnel at Mach numbers up to 1.20.

Proceedings ArticleDOI
24 Jun 1991


Patent
27 Nov 1991
TL;DR: In this article, the authors presented a utility model for petroleum gas liquefaction, which consists of an air heat exchanger, a turbo compressor, a light hydrocarbon separator, and a liquefied natural gas separator.
Abstract: The utility model relates to a separating device for petroleum gas liquefaction, belonging to oilfield and the processing unit of the gas processing plant, which is composed of an air heat exchanger, a turbo compressor, a light hydrocarbon separator, a liquefied natural gas separator. The utility model is characterized in that the utility model is provided with a compressor, a birotor aircraft turbofan engine which is incorporated with the prime motor, a power turbine, a power turbine, a deep cooling expansion turbine, an intermediate pressure compressor, a generator, a gas vessel and a heat transfer cold box which are driven by the birotor aircraft turbofan engine. The utility model liquidizes the processed gas by the two-stage refrigeration of the by-pass air of the aerial engine and the compressed medium pressure air of the intermediate pressure compressor. The utility model can be directly modified from an aerial engine in order to decrease the cost of designing and manufacture.


Patent
25 Feb 1991
TL;DR: In this article, a power plant is provided with a first compressor 20 producing a downstream axial flow and a second compressor 22 installed on downstream side, and on the downstream side of the second compressor 24, a combustor 24 is installed.
Abstract: PURPOSE: To facilitate conversion of an aircraft turbofan engine to a non-aircraft turbofan engine by disposing two compressors in series and two turbines on the downstream side of a combustor in series respectively, and connecting a first turbine to a second compressor and a second turbine to a first compressor respectively. CONSTITUTION: This power plant is provided with a first compressor 20 producing a downstream axial flow and a second compressor 22 installed on the downstream side, and on the downstream side of the second compressor 22, a combustor 24 is installed. A first and second turbines 28, 36 are driven sequentially by high temperature and pressure combustion gas produced by the combustor 24. The second and first compressors 22, 20 are driven respectively through a first and second shafts 32, 40 by the first and second turbines 28, 36. Load such as a generator, a compressor or a propulsion propeller for ship is connected to a connecting means 44 connected to the second shaft 40.

Proceedings ArticleDOI
24 Jun 1991


01 Oct 1991
TL;DR: The first year of data collection was from October 1986 through September 1987 as discussed by the authors, and the first year extended from the Boeing 737 model aircraft to the CFM International CFM56 large inlet area turbofan engine.
Abstract: : The Federal Aviation Administration (FAA) Technical Center initiated a study in October 1986 to determine the numbers, sizes, and types of birds which are being ingested into medium and large inlet area turbofan engines and to determine what damage, if any, results. Bird ingestion data are being collected for the Boeing-737 model aircraft which uses either the Pratt and Whitney JT8D medium inlet area turbofan engine or the CFM International CFM56 large inlet area turbofan engine. This interim report analyzes the first of 3 years of data collection. The first year extends from October 1986 through September 1987. Keywords: Bird ingestion; Turbofan engine; Statistical analysis.