Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
  • F01D11/00—Preventing or minimising internal leakage of working-fluid, e.g. between stages
  • F01D11/001—Preventing or minimising internal leakage of working-fluid, e.g. between stages for sealing space between stator blade and rotor
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
  • F01D5/00—Blades; Blade-carrying members; Heating, heat-insulating, cooling or antivibration means on the blades or the members
  • F01D5/12—Blades
  • F01D5/22—Blade-to-blade connections, e.g. for damping vibrations
  • F01D5/225—Blade-to-blade connections, e.g. for damping vibrations by shrouding
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
  • F01D5/00—Blades; Blade-carrying members; Heating, heat-insulating, cooling or antivibration means on the blades or the members
  • F01D5/12—Blades
  • F01D5/28—Selecting particular materials; Particular measures relating thereto; Measures against erosion or corrosion
  • F01D5/282—Selecting composite materials, e.g. blades with reinforcing filaments
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
  • F01D5/00—Blades; Blade-carrying members; Heating, heat-insulating, cooling or antivibration means on the blades or the members
  • F01D5/12—Blades
  • F01D5/28—Selecting particular materials; Particular measures relating thereto; Measures against erosion or corrosion
  • F01D5/284—Selection of ceramic materials
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
  • F01D5/00—Blades; Blade-carrying members; Heating, heat-insulating, cooling or antivibration means on the blades or the members
  • F01D5/34—Rotor-blade aggregates of unitary construction, e.g. formed of sheet laminae
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02C—GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS
  • F02C1/00—Gas-turbine plants characterised by the use of hot gases or unheated pressurised gases, as the working fluid
  • F02C1/04—Gas-turbine plants characterised by the use of hot gases or unheated pressurised gases, as the working fluid the working fluid being heated indirectly
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02K—JET-PROPULSION PLANTS
  • F02K7/00—Plants in which the working fluid is used in a jet only, i.e. the plants not having a turbine or other engine driving a compressor or a ducted fan; Control thereof
  • F02K7/10—Plants in which the working fluid is used in a jet only, i.e. the plants not having a turbine or other engine driving a compressor or a ducted fan; Control thereof characterised by having ram-action compression, i.e. aero-thermo-dynamic-ducts or ram-jet engines
  • F02K7/18—Composite ram-jet/rocket engines
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
  • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
  • F05D2300/00—Materials; Properties thereof
  • F05D2300/20—Oxide or non-oxide ceramics
  • F05D2300/22—Non-oxide ceramics
  • F05D2300/224—Carbon, e.g. graphite
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
  • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
  • F05D2300/00—Materials; Properties thereof
  • F05D2300/60—Properties or characteristics given to material by treatment or manufacturing
  • F05D2300/603—Composites; e.g. fibre-reinforced
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
  • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
  • F05D2300/00—Materials; Properties thereof
  • F05D2300/60—Properties or characteristics given to material by treatment or manufacturing
  • F05D2300/603—Composites; e.g. fibre-reinforced
  • F05D2300/6033—Ceramic matrix composites [CMC]

Definitions

• the present disclosure relates to rotors for turbomachines such as turbine rotors or compressor rotors and engines including such rotors.
• SSTO single stage to orbit
• One example of this may be an aircraft having an engine with two modes of operation: an air-breathing mode and a rocket mode capable of propelling the aircraft to speeds beyond Mach 5, e.g. into orbit.
• Embodiments of the present disclosure attempt to mitigate at least some of the above-mentioned problems.
• a turbomachine apparatus (such as a turbine, e.g. for driving a compressor) comprising at least one rotor stage and at least one retaining element, wherein the at least one rotor stage comprises a plurality of blades and is configured to rotate about an axis, and wherein the at least one retaining element is configured to retain the at least one rotor stage with the blades thereof at least partly or wholly in radial compression during rotation thereof.
• the at least one retaining element may be configured to support a centrifugal load on the at least one rotor stage.
• the at least one retaining element may be a shroud ring.
• the at least one retaining element may be formed of a circumferentially-reinforced fibre material.
• the at least one retaining element may be formed of carbon-carbon (or a matrix of graphite reinforced with carbon fibres). Other materials of suitable strength and
• weight/density may also be used to form the retaining element.
• the at least one retaining element may be configured to force the plurality of blades into compression.
• the plurality of blades may be formed of a ceramic material.
• the ceramic material may be silicon nitride.
• the at least one rotor stage may further comprise a hub to which the plurality of blades may be fixed.
• the turbomachine may be a gas turbine.
• the gas turbine may be adapted to run on helium.
• the at least one rotor stage may be adapted to receive gas, such as helium, for example between 900K and 1500K.
• gas such as helium
• the temperature may be 1200K being an example.
• the blades and the at least one retaining element may be separately formed components, which may have been joined together after the separate manufacture thereof.
• the blades and the at least one retaining element may be joined by diffusion bonding or brazing or any other suitable material joining process.
• the blades and the hub may be separately formed components, which may have been joined together after the separate manufacture thereof. [0021] The blades and the hub may be joined by diffusion bonding.
• the blades may be configured to withstand a compressive load applied thereto by the at least one retaining element.
• the blades may be configured to withstand the operational temperature of the turbine substantially without degradation due to temperature.
• the turbomachine may be a contra-rotating turbine.
• Another aspect provides a rotor stage having a plurality of blades and at least one retaining element configured to retain the blades in radial compression during rotation thereof.
• an engine comprising a turbomachine according to previous aspects of the disclosure.
• a further aspect comprises a flying machine including such an engine.
• the turbomachine may be a turbine arranged for use in at least an air-breathing mode of the engine.
• the turbine runs at extremely high temperatures, which traditional metal alloy parts cannot easily endure. Metal parts are also generally of high weight relative to ceramic materials. Ceramic turbine blades are useful due to the favourable temperature resistance and low density of ceramic materials relative to metallic materials. Despite low tensile strength and the brittle nature of ceramic matrix material, the devices in accordance with the embodiments disclosed herein can withstand the loads and temperatures encountered during operation.
• Figure 1 shows in cross-section part of a turbine blade arrangement according to an embodiment.
• FIG. 1 depicts a turbine blade arrangement according to an embodiment.
• the contra- rotating turbine 100 comprises stator blades 102, rotor blades 104, drum 106 and shroud ring 108.
• Stator blades 102 and rotor blades 104 are formed of a monolithic ceramic material, for example silicon nitride. In other embodiments, other ceramic materials are used.
• Shroud ring 108 is formed of a circumferential-fibre-reinforced material, specifically carbon-carbon in the form of a carbon fibre reinforced graphite matrix of material.
• the carbon-carbon is not oxidised during operation.
• Carbon-carbon also has a low density relative to metallic materials and suitably high tensile stress relative to monolithic ceramic materials.
• other materials are used.
• Each of the components is manufactured separately.
• components may be manufactured as a single unit.
• the blades 102 and 104 are joined to the drum 106 and to the shroud ring 108 by diffusion bonding. In other embodiments, other bonding processes are used.
• helium is passed through the stator and rotor stages of the turbine.
• the helium may arrive at the turbine at 1200K.
• the rotor rotates at speeds between 5000rpm and 20000rpm.
• the rotor blades 104 experience a centrifugal load.
• the load is between 50,000N/kg and 200,000N/kg.
• the rotor blades 104 are fixed at a hub, in the embodiment at around 450mm from the axis of rotation of the rotor.
• the hub to tip length of the rotor blades 104 in the embodiment, is around 500mm.
• the rotor blades 104 are restrained at the tip by the shroud ring 108 and are forced into compression.
• the shroud ring 108 carries the centrifugal load of the assembly. As ceramics have poor tensile strength and fracture toughness, the shroud ring 108 reduces the risk of failure of the rotor blades 104.
• the circumferential fibres of the shroud ring 108 support the circumferential load present in the shroud ring.
• Ceramic blades 102 and 104 are able to withstand high temperatures.
• silicon nitride is capable of withstanding temperatures over 1500K. Therefore the temperature of the helium through the turbine 100 can be increased in relation to conventional turbines. Furthermore, there is no need for cooling of the blades 102 and 104. Higher temperatures of operation also increase the efficiency of the engine, and reduce specific fuel consumption. Silicon nitride is also of low density relative to metallic materials, thus the weight of the engine is reduced.
• silicon nitride can be manufactured easily and with a generally smooth surface.
• Ceramic blades 102 and 104 are also lighter than conventional metal blades.
• the centrifugal load on the shroud ring 108 is reduced.
• the overall weight of the turbine 100 is also reduced.
• the increased strength to weight ratio of the system permits an increase in turbine tip speed of around 25%, resulting in further improvements in the power to weight ratio of the engine. Joints between the blades 102 and 104, the drum 106 and the shroud ring 108 may be easily manufactured due to the radial clamping load provided by the radial restraint of the shroud ring 108.
• This system is applicable to any turbomachine rotor, for example, axial flow compressors and turbines or centrifugal flow compressors and turbines.
• Application to high hub/tip ratio turbines may be particularly relevant due to the high resistance to buckling of short turbine blades.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Materials Engineering (AREA)
• Combustion & Propulsion (AREA)
• Ceramic Engineering (AREA)
• Composite Materials (AREA)
• Structures Of Non-Positive Displacement Pumps (AREA)
• Turbine Rotor Nozzle Sealing (AREA)

Applications Claiming Priority (3)

Publications (1)

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Family Applications (1)

Country Status (4)

Family Cites Families (17)

• 2013
  • 2013-10-11 GB GB1318103.7A patent/GB2521588A/en not_active Withdrawn
• 2014
  • 2014-06-05 US US14/296,611 patent/US20150104316A1/en not_active Abandoned
  • 2014-10-10 WO PCT/GB2014/000403 patent/WO2015052467A1/en not_active Ceased
  • 2014-10-10 EP EP14784334.6A patent/EP3055508A1/de not_active Withdrawn

Non-Patent Citations (1)

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