Asea Brown Boveri Inc.

Bbc Brown, Boveri & Company, Limited

Asea Brown Boveri Ag

Alstom Technology Limited

Alstom (Switzerland) Ltd

Bbc Brown Boveri Ag

Abb Management Ag

Franz Kreitmeier

A power generation plant includes a conventional steam turbo train, a high temperature turbo train, and a coal fired boiler () with a fluidized bed combustor. The high temperature turbo train is particularly arranged vertically and in parallel with the coal fired boiler () and separately from the conventional turbo train. Transfer flow lines () are run from the boiler () to the high temperature turbines over minimal lengths. The arrangement of the two turbo trains separately from one another and the vertical arrangement of the high temperature turbo train are advantageous in terms of plant efficiency and fabrication and maintenance thereof.

Coal fired power generation plant

A recuperator ( ) in a thermal power installation such as, for example, a gas turbine installation or air storage power installation, having turbines ( ) and a generator (G), has sectors (S -S ) with tubes for the circulation of air. Hot exhaust gases from the turbines ( ) are supplied to the recuperator ( ) for the purpose of heating the air flowing through the sectors (S -S ). According to the invention, the recuperator ( ) has one or a plurality of external heat storage devices (HS HS HS ) which are connected between the (S -S ) of the recuperator ( ) and are heated during the normal operation of the power installation. During an outage period of the power installation, air is circulated through the installation components ( ), a temperature distribution being maintained in these components with temperature differences which are smaller than a critical magnitude with respect to transient thermal stresses in the components of the recuperator. After an outage period, the power installation can be started up to full load in a short time and without risk with respect to transient thermal stresses in the recuperator ( ), turbines ( ) and combustion chamber ( ).

Recuperator for thermal power installation

In a method for cooling a turbine ( ), the supply of the cooling medium is regulated in accordance with the third power of the rotor rotational speed. The method is particularly employed in the period while the rotors run down after the termination of the on-load operation of the turbine ( ). The method ensures that cooling takes place according to requirement and a critical phase with respect to vibrations of the long blades can not, as far as possible, be reached.

Cooling method for turbines

An axial/radial three-channel diffuser is provided with two guide vanes for dividing the diffuser into three partial diffusers that are distributed so that the distribution of the surface area over the three partial diffusers in the inlet surface area is uneven. The guide vanes are oriented in accordance with the total pressure field after the last rotating blade row and are arranged at a minimum distance from the trailing edge of the last rotating blade row. Because of its long extension in relation to the channel heights of the partial diffusers, the three-channel diffuser brings about a gentle deflection of the diffuser flow. The diffuser according to the invention results in an improved pressure recovery and increased turbine performance.

Low-pressure steam turbine with multi-channel diffuser

In a device for sealing the gap between the moving blades and the stator, designed with a conical contour, of a turbomachine, the moving blades are provided at the blade end with encircling shroud plates. These shroud plates project into a cavity in the stator and, while forming radial gaps, make a seal against the stator, which is provided with sealing strips. The cavity at the labyrinth inlet is subdivided in its radial extent into at least two axially staggered cavities. The shroud plate is of stepped design with at least two choke points with respect to the stator, the sealing strips acting on one step each while enclosing a vortex chamber. A curved sealing strip which runs at least approximately horizontally preferably acts on each step of the shroud plate.

Shroud band for an axial-flow turbine

A multi-stage blade system of an axial flow turbo machine includes a wall (10, 11), which is on either the rotor side, the stator side, or both, which bounds the flow through the channel through which flow passes. The wall is provided, immediately at the outlet of the rotor blades (La1, La2, La3), with a kink angle (A, AA). This kink angle (A, AA) is dimensioned such that the outlet flow from the rotor blades is homogenized in terms of the total pressure and outlet flow angle. The wall (10, 11) is also provided with an opposing kink angle (B, BB) at least approximately in the inlet region of the stator blades (Le2, Le3) of the following stage. This allows the labyrinth mass flow to be reduced in blade systems having covering strip sealing.

Multi-stage blade system

In a diffusor for an axial-flow steam turbine with an axial/radial diffusor, the kind angles Of the diffusor inlet both at the hub and at the cylinder of the turbo-machine are determined solely for the purpose of equalizing the total pressure profile over the channel height at the outlet of the last blade row. The diffusor is subdivided from the inlet to the outlet into an inner and an outer channel by a radially outward-curved guide plate. Within the deceleration zone of the diffusor, radial-flow flow ribs are arranged in the outer channel and diagonal-flow flow ribs are arranged in the inner channel for canceling the rotation of the rotational flow.

Diffusor for a turbo-machine with outwardly curved guide plate

In a diffusor for an axial-flow steam turbine with an axial/radial diffusor, the kink angles of the diffusor inlet both at the hub and at the cylinder of the turbo-machine are determined solely for the purpose of equalizing the total pressure profile over the channel height at the outlet of the last blade row. The diffusor is subdivided from the inlet to the outlet into an inner and an outer channel by a radially outward-curved guide plate. Within the deceleration zone of the diffusor, radial-flow flow ribs are arranged in the outer channel and diagonal-flow flow ribs are arranged in the inner channel for canceling the rotation of the rotational flow.

Diffusor for a turbo-machine with outwardly curved guided plate

In a radial-axial inlet housing of rotating thermal machines, a flow divider is disposed in the turbine or compressor inlet, in front of the inlet and opposite the first turbine guide vane row or the compressor ribs. The flow divider in this case is disposed in the central lower stagnation point of the housing flow. It has a thick-headed profile with a straight median line. The rear side of the flow divider, seen in the direction of flow, is disposed perpendicularly to the rotary shaft at a distance from the first guide vane row or the ribs. There is a gap between the radially inner side of the flow divider and the housing wall, and the chord length of the flow divider decreases radially outwardly. The leading edge of the flow divider, seen in the direction of flow, is inclined like a straightened potential line relative to the housing wall.

Flow divider for radial-axial inlet housings

A multi-zone diffuser for an axial-flow turbomachine has a minimal overall length and a first zone with a minimal diameter. The kink angles of the diffuser inlet both at the hub and at the cylinder of the turbomachine are fixed exclusively for evening out the total pressure profile over the duct height at the outlet from the last rotor blade row. In the form of streamlined struts, are provided within the deceleration zone of the diffuser for the removal of swirl from the swirling flow. A first diffusion zone extends from the outlet plane of the last rotor blade row to a plane at the outlet of the streamlined struts and is configured as a single duct and as a bell shaped diffuser. A second diffusion zone is fashioned in the form of a multi-duct diffuser part, flow guide rings being arranged downstream of the streamlined struts.

Multi-zone diffuser for turbomachine

In a device for sealing the gap between the rotor blades and the casing (2) of a turbomachine, configured with a conical profile (28), the rotor blades (6) are provided with circumferential shroud plates (11), which seal by serrations (12, 13, 14, 15) against the casing with the formation of radial gaps (16, 17, 18). The shroud plate (11), which is arranged at the end of the blade, has four throttle locations relative to the casing, the inlet end throttle location bounding a diagonal gap (19) and the outlet end throttle location forming a radial gap (16).

Shroud ring for an axial flow turbine

In a device for sealing the gap between the rotor blades and the casing (2) of a turbomachine, configured with a conical profile (28), the rotor blades (6) are fitted with circumferential shroud plates (11), which seal by virtue of serrations (12, 13, 14) against the casing by the formation of radial gaps (16, 17). The tips (24, 29) of the conical ends of the blades (6) seal against the casing (2) at the inlet and outlet ends, and the shroud plate (11) located centrally at the end of the blade has three throttle locations relative to the casing, the inlet end throttle location bounding a diagonal gap (19). The end of the blade is provided with a positive offset (31) relative to the passage profile, which protrudes into a gap relief chamber (25) located in the vane carrier (2).

In a single-shaft axial-flow gas turbine, the shaft part lying between turbine and compressor is a drum (12) which is surrounded by a drum cover (13). The annular passage (18) formed between drum and drum cover assumes the function of conducting all the rotor cooling air, tapped on the hub side behind the last moving row of the compressor, to the front end (16) of the turbine and after this to its rotor-side cooling passages. The cooling air is deflected inside the annular passage in a spin cascade (25) and accelerated to the highest possible tangential velocity. With this measure, the axial thrust of the gas turbine can be reduced on the one hand and the hitherto conventional recooler for the cooling air can be dispensed with on the other hand.

Axial-flow gas turbine cooling arrangement

An axial flow turbine, whose outlet rotor blades (12) are followed by a diffuser (13), has first means (8) within the retardation zone of the diffuser for swirl removal from the swirling flow. A row with adjustable guide vanes (11) is arranged between these first means for swirl removal in the form of aerodynamic ribs and the outlet rotor blades. These guide vanes (11) have a straight mean camber line with a symmetrical aerofoil section, are conically shaped in the radial direction and are twisted. In addition to a substantial improvement in the pressure recovery over a wide load range, this measure also permits the vortex usually occurring between the rotor blades and the aerodynamic ribs to be prevented.

Axial flow turbine

The cooling-air ducting of the axial flow gas turbine runs in the area of the last blading stage (9+14) radially inwards of the heat-accumulation segments (23, 24) inside the outer boundary of the rotor (4) and through blade root channels (21) in the blade roots of the last moving blade ring (9) and finally through a cooling-air blade ring (28) fixed to the rotor into the diffuser into which the cooling-air flow enters with a velocity vector which essentially corresponds to the average velocity vector of the exhaust-gas flow entering into the diffuser. This avoids the flow losses which occur when the cooling-air flow passes out into the exhaust-gas flow in the area of the last stage or stages. At the same time, the temperature difference between the rotor circumference and the last rotor disk (4), likewise cooled by tapped air from the compressor, is in this way reduced, as a result of which the thermal stresses in the rotor are also reduced.

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Baden, Switzerland

Franz Kreitmeier