Showing papers on "Ram air turbine published in 2008"

Ultraminiaturized High-Speed Permanent-Magnet Generators for Milliwatt-Level Power Generation

Abstract: This paper presents the design, fabrication, and characterization of millimeter-scale rotary electromagnetic generators. The axial-flux synchronous machines consist of a three-phase microfabricated surface-wound copper coil and a multipole permanent-magnet (PM) rotor measuring 2 mm in diameter. Several machines with various geometries and numbers of magnetic poles and turns per pole are designed and compared. Moreover, the use of different PM materials is investigated. Multipole magnetic rotors are modeled using finite element analysis to analyze magnetic field distributions. In operation, the rotor is spun above the microfabricated stator coils using an off-the-shelf air-driven turbine. As a result of design choices, the generators present different levels of operating frequency and electrical output power. The four-pole six-turn/pole NdFeB generator exhibits up to 6.6 mWrms of ac electrical power across a resistive load at a rotational speed of 392 000 r/min. This milliwatt-scale power generation indicates the feasibility of such ultrasmall machines for low-power applications. [2008-0078].

Turbine drive system with lock-up clutch and method

Abstract: A pneumatically driven turbine drive system is coupled to a gas turbine engine that includes low and high pressure compressors, low and high pressure turbines, a lock-up clutch, and at least one engine accessory driven by the high pressure compressor. The pneumatically driven turbine drive system selectively bleeds air discharged from the high pressure compressor and supplies it to an air turbine that is coupled to the at least one engine accessory. Thus, the system selectively reduces the power extracted from the high pressure compressor and is capable of supplying power back to the engine core. This, coupled with the bleed air that is diverted from the high pressure turbine and the low pressure turbine, allows the high pressure spool and the low pressure spool to run at lower speeds when high engine thrust is not needed or desired, but when the at least one engine accessory is still needed.

Power generating plant

Abstract: During operation of a power generating plant, which essentially comprises a gas turbogroup, a compressed air accumulator, an air turbine which is equipped with at least one generator, the compressed air which is extracted from the compressed air accumulator is directed through a heat exchanger, which acts on the outflow side of the gas turbogroup, and is thermally conditioned there. This compressed air then charges the air turbine, wherein during a “black out” or other shutdown of the power generating plant, the electric current energy which can be obtained by means of the thermally conditioned compressed air in the air turbine, via a power line is used directly for start-up of the gas turbogroup.

Power augmentation of combustion turbines by injection of cold air upstream of compressor

Abstract: A combustion turbine power generation system (10) includes a combustion turbine assembly (11) including a main compressor (12) for receiving ambient inlet air, a main expansion turbine (14) associated with the main compressor, a combustor (16) for receiving compressed air from the main compressor and to feed the main expansion turbine, and an electric generator (15) associated with the main expansion turbine for generating electric power. Pressure reducing structure (28) reduces pressure of compressed air from a source of compressed air to atmospheric pressure and thus to reduce a temperature of the compressed air from the source of compressed air to a temperature below ambient temperature when exhausted from the pressure reducing structure. Structure (32) is associated with the pressure reducing structure to permit mixing of the air exhausted from the pressure reducing structure and the ambient inlet air to reduce a temperature of inlet air to the main compressor and thus increase the combustion turbine assembly power.

Sensorless Operation of a Permanent-Magnet Generator for Aircraft

Abstract: This paper considers the operation and control of a brushless AC prototype embedded aircraft generator that has been designed for use as an alternative to the emergency run air turbine. To meet the wide operating speed requirements, the generator utilizes a hybrid rotor construction comprising permanent magnet and variable reluctance sections. The constant current source characteristics of the design are exploited to derive the phase information required by the AC vector controller, thus avoiding the use of a shaft-mounted rotor position sensor. The methodology behind the controller operation is presented together with test results taken from a prototype generator system, and this is contrast with the results taken from the conventionally controlled machine with resolver position feedback.

Gas turbine power generator plant and silencer for the same

Abstract: A gas turbine power generator plant, intended to reduce its noise by making small the intake and exhaust outlets of the cooing air channel of a case, comprises an engine core in which a turbine, a compressor and a generator are installed on the same axis, a combustor for burning air for combustion compressed by the compressor and supplying the air to the turbine, a radiator for cooling a coolant or a lubricant, a cooling fan for ventilating the radiator with cooling air, an electric power converter for converting electric power generated by the generator, and the case for housing these constituent elements. And, a combustion air channel passing the compressor, the combustor and the turbine and a cooling air channel passing the radiator, the cooling fan and the electric power converter are formed as mutually independent channels from intake to exhaust.

Development of a vaned-type novel air turbine:

Abstract: Worldwide depletion of fossil fuel due to its greater utilization is causing a serious threat to the environment. This has drawn global attention to its conservation, and the search for an alternative to fossil fuel driven engines. Compressed air is a potential working fluid for generating shaft work, and it can be a viable alternative to run light motor vehicles with reasonably small inbuilt compressed air tanks. In this article, the details of the development of a small air turbine with vaned-type rotor are presented. The proposed air turbine has been developed, and is in the process of being tested. Results based on its testing are presented here.

Humid air turbine, humid air turbine control system, and humid air turbine control method

Abstract: The present invention provides a humid air turbine having a compressor, a humidificator for generating humid air by adding moisture to compressed air supplied from the compressor, a combustor, a turbine, a recuperator for effecting heat exchange between exhaust from the turbine and the humid air, an economizer for effecting heat exchange between exhaust from the recuperator and water, and a system for supplying the water heated by the economizer to the humidificator. The humid air turbine includes a temperature measurement device for measuring the temperature of gas discharged from the economizer, and a control device for adjusting the amount of moisture to be supplied to the humidificator in accordance with a temperature signal from the temperature measurement device. The present invention assures low NOx of combustor and flame stability before and after water addition to the humid air turbine.

Method and systems for operating a combined cycle power plant

Abstract: An embodiment of the present invention may provide a variable speed booster, which receives air from a compressor of a gas turbine through an intercooler, to supply air at a relatively constant pressure to an air processing unit. An embodiment of the present invention may provide a speed adjustable booster turbine to energize a variable speed booster; which provides air at a relatively constant pressure to an air processing unit.

A Study on the Effects of Blade Profile and Non-Uniform Tip Clearance of the Wells Turbine

Abstract: Several of wave energy devices being studied under many wave energy programs in the United Kingdom, Japan, Portugal, India and other countries make use of the principle of an oscillating water column (OWC). In such wave energy devices, a water column which oscillates due to wave motion is used to drive an oscillating air column which is converted into mechanical energy. The energy conversion from the oscillating air column can be achieved by using a self-rectifying air turbine. Wells turbine is a self-rectifying air turbine which is expected to be widely used in wave energy devices with OWC. There are many reports which describe the performance of Wells turbine both at starting and running characteristics. According to these results, Wells turbine has inherent disadvantages: lower efficiency, poorer starting and higher noise level in comparison with conventional turbines. In order to enhance the performance of Wells turbine, some rotor blade profiles have been recommended by various researchers. The aim of this study is to investigate the effect of rotor blade profile on the performance of Wells turbine. In the study, four kinds of blade profile were selected and tested by model testing under steady flow condition. The types of blade profile are as follows: NACA0020; NACA0015; modified NACA0015; and modified Eppler472. The experimental investigations have been performed by use of test section with a casing diameter of 300 mm. Further, the effect of non-uniform tip clearance on the turbine performance was tested and the result was compared with that of the case of Wells turbine with uniform tip clearance. As an additional experiment, the effects of blade profile and non-uniform tip clearance on the performance under unsteady flow condition have been investigated numerically by using a quasi-steady analysis.Copyright © 2008 by ASME

Gas turbine aircraft engine with power variability

Abstract: A gas turbine aircraft engine with power variability is provided. The gas turbine aircraft engine comprises a compressor and a turbine mounted on a common shaft, and, a continuously variable transmission coupled to the shaft for transmitting power to a propulsion load.

Test Results From the Advanced Humid Air Turbine System Pilot Plant: Part 2—Humidification, Water Recovery and Water Quality

Abstract: The AHAT (advanced humid air turbine) system has been studied to improve thermal efficiency of gas turbine power generation. This is an original gas turbine power generation system which substitutes the WAC (water atomization cooling) system for the intercooler system of the HAT cycle. A pilot plant was built to verify feasibility of the AHAT system, which is composed of a gas turbine, a humidification tower, a recuperator and a water recovery system. Firstly, characteristics of the humidification tower were examined. The experimental results of the humidification rate agreed with the calculation results within a deviation of 1%. Humidification increased the heat recovery, and the electrical efficiency exceeded 40%. Secondly, characteristics of the spray-type water recovery system were examined. 95% of water consumed by the humidification tower was recovered, and a significant reduction of the make-up water for the HAT cycle was confirmed. Thirdly, concentrations of impurities within the circulating water of the AHAT system were measured when the recovered water was recycled without any purification process.Copyright © 2008 by ASME

Ocean Wave Energy Systems Design: Conceptual Design Methodology for the Operational Matching of the Wells Air Turbine

Abstract: The paper has set out a conceptual design methodology that was employed in the design of a Wells air turbine for OWC ocean wave energy plants. In particular, the operational matching of the performance of the turbine is used as the premise in achieving an optimal design configuration and sizing, given the range and frequency of power bands presented to the turbine over long periods of time. This is in contrast to designing the turbine to accommodate the average power rating delivered by the OWC. It was seen that this resulted in a 5% improvement in power output with the optimal size of the turbine required to be slightly larger than the average pneumatic power rating would suggest.

Test Results From the Advanced Humid Air Turbine System Pilot Plant: Part 1 — Overall Performance

Abstract: The AHAT (advanced humid air turbine) system is based on a recuperated cycle using high-humidity air. This system improves thermal efficiency by using the high-humidity air as working gas. After many studies and elemental tests, a 4MW-class pilot plant was planned and built in order to verify feasibility of the AHAT system from the viewpoints of heat cycle characteristic and engineering. This plant consists of a gas turbine, a recuperator, a humidification tower, a water recovery system, an economizer, and other components. The gas turbine consists of a two-stage centrifugal compressor (pressure ratio of 8), a reverse-flow type single-can combustor, and a two-stage axial-flow turbine. In overall performance tests, the plant thermal efficiency exceeded 40%LHV.Copyright © 2008 by ASME

High-speed air spindle

Abstract: A high-speed air spindle including a spindle 1 supported by a first bearing 3 at the leading end side in the axial direction and a second bearing 2 at the rear end side, a driving air turbine 4 fixed in a spindle portion between the first bearing 3 and the second bearing 2, a speed-increasing air turbine 5 fixed in a spindle portion ahead of the first bearing 3, and an air passage 9 of an exhaust of compressed air supplied in the driving air turbine 4, flowing in the sequence of the first bearing 3 and the speed-increasing air turbine 5.

Off-shore wind turbine generator and off-shore wind farm

Abstract: An object is to provide an off-shore wind turbine generator capable of obtaining accurate information about the situation of a wind turbine itself, surrounding weather conditions, and the like. The off-shore wind turbine generator of the present invention generates power by driving a generator mechanism through the rotation of a rotor head to which wind turbine blades are attached and includes a monitoring apparatus (10) for monitoring the wind turbine generator itself and its surrounding circumstances.

Wave power conversion

Abstract: A wave power generator device comprises tubes (114) which are open at their lower end to allow water to enter the tubes (114) as a wave passes. The tubes may be carried on a floating vessel (100) having hulls (104). As the water level in the tubes rises, air exits the tube via non-return outlet valves into an air chamber (116). As the water level in the tube falls, air feeds into the tube via non-return inlet valves. The air may be fed from the chamber (116) and used to drive an air turbine (108) and electricity generator (110). A system for removably supporting the tubes (114) between the hulls (104) is also disclosed.

Ram air turbine

Abstract: A ram air turbine for a vehicle comprises a turbine 2 mounted within a compartment 3 to the side of a fluid stream 5 in use, the turbine 2 being selectively deployable from the compartment 3 and into the fluid stream to provide drag and/or electrical power through an electrical machine associated with the turbine 2. The compartment may have a door 6 which is displaced when the turbine 2 is deployed. The vehicle may be an aircraft and the turbine 2 may be deployed during a period of descent or deceleration of the aircraft. The ram air turbine may directly power electrical systems of the vehicle, possibly by pulse activation. Alternatively the power generated may be stored electrically (batteries), mechanically or pneumatically (compressed gas). The ram air turbine may provide a power supply distinct in terms of current, voltage or frequency from other power supply systems in the vehicle. The turbine 2 may have variable pitch blades 8, and the angle of the turbine 2 in the fluid flow may be adjustable. The vehicle could also be ship, the ram air turbine being used to assist steering or braking as well as electrical power generation.

Method and apparatus for operating an aircraft landing system

Abstract: A method and apparatus is disclosed in which an aircraft landing system is at least partly primarily powered by power provided by a ram air turbine (RAT).

Resonance reduction device for ram air turbine

Abstract: A ram air turbine assembly includes a preferentially located mass that modifies the resonance frequency of the assembly so that vibration is reduced to desired levels. The example mass can be fixed in a specific location on the ram air turbine or can be deployable once the ram air turbine is moved to an operating position.

Development of Elemental Technologies for Advanced Humid Air Turbine System

Abstract: The advanced humid air turbine (AHAT) system improves the thermal efficiency of gas turbine power generation by using a humidifier, a water atomization cooling (WAC) system, and a heat recovery system, thus eliminating the need for an extremely high firing temperature and pressure ratio. The following elemental technologies have been developed to realize the AHAT system: (1) a broad working range and high-efficiency compressor that utilizes the WAC system to reduce compression work, (2) turbine blade cooling techniques that can withstand high heat flux due to high-humidity working gas, and (3) a combustor that achieves both low NOx emissions and a stable flame condition with high-humidity air. A gas turbine equipped with a two-stage radial compressor (with a pressure ratio of 8), two-stage axial turbine, and a reverse-flow type of single-can combustor has been developed based on the elemental technologies described above. A pilot plant that consists of a gas turbine generator, recuperator, humidification tower, water recovery system, WAC system, economizer, and other components is planned to be constructed, with testing slated to begin in October 2006 to validate the performance and reliability of the AHAT system. The expected performance is as follows: thermal efficiency of 43% (LHV), output of 3.6MW, and NOx emissions of less than 10ppm at 15% O2. This paper introduces the elemental technologies and the pilot plant to be built for the AHAT system.

Electric motor driven lubrication pump control system and method for turbomachine windmill operation

Abstract: A system and method are provided to selectively control lubricant supply flow to a rotating machine that is installed in an aircraft having ram air turbine that is movable between at least a deployed position and a stowed position. A controller determines at least when the ram air turbine is in the deployed position, and determining when rotational speed of the rotating machine exceeds a predetermined value. The electric motor driven lubrication pump is at least selectively energized to control the measured lubricant pressure to a predetermined minimum pressure at least when the ram air turbine is deployed and the rotational speed exceeds the predetermined value.

Air turbine for a wave power station

Abstract: The invention relates to an air turbine for a wave power station, which is driven by a bidirectional current of air and which comprises at least one rotor arrangement having a first rotor, and at least one second rotor arrangement having a second rotor; the first rotor and the second rotor maintaining their sense of rotation, independent of the direction of incoming air, when the air turbine is operated, and defining an axially flown rotor pair in a flow channel, one of the rotors being the upstream rotor and the other rotor being the downstream rotor depending on the direction of incoming air. The air turbine is characterized in that guide vanes are arranged between the first rotor and the second rotor and reduce the spin of the air current produced by the upstream rotor.

Free Turbine Generator For Aircraft

Abstract: A turbine engine for an aircraft is disclosed. The turbine includes a turbine generator which is not connected to the low or high pressure spools of the turbine engine. The generator is used to create power for use in electrical systems in the aircraft. In some embodiments, the free-turbine airfoils receive the core air through an array of variable-pitch vanes. The pitch of these vanes is alterable to control the core air so that the speed of the free turbine remains substantially constant even though engine speed fluctuates.

Stoichiometric compression ignition engine with increased power output

Abstract: A stoichiometric compression ignition engine has a turbocharger coupled to it so that the exhaust from the engine feeds the turbine and the compressor provides combustion air past a throttle and intercooler to the engine intake manifold. An exhaust after treatment device is positioned before the exhaust of the engine. A power turbine is connected in parallel relation to the turbocharger turbine and is controlled by a valve to operate the power turbine whenever either the turbocharger compressor boost or the turbocharger turbine back pressure exceed given limits. The power turbine is connected by a power transmission device to either couple to the engine output or to an electrical generator. An EGR loop may be driven by a pump also connected to the power turbine to lower in cylinder pressures.

Power generation system for an aircraft

Abstract: A power generation system for propelling, and generating electrical power in, an aircraft, using a gas turbine engine (14) coupled to a turbine starter/generator unit (50) having therein an electrical machine capable of being selected to be alternatively a motor and an electrical power generator and having a coupling shaft (51) extending therefrom to be engaged with the air compressor (23) in the gas turbine engine and further having an interconnection conductor for electrical energization. An internal combustion engine (34) provided as an intermittent combustion engine in the aircraft has an air intake (32) coupled through an air transfer duct (30) connected to the air compressor (23) to allow the transfer of compressed air thereto, and has in connection therewith a supply starter/generator unit (44) with a coupling shaft (43) extending therefrom to be engaged with the intermittent combustion engine power shaft (40). An interconnection conductor (45') therein for electrical energization is electrically interconnected with the turbine starter/generator unit interconnection conductor.