Rotary kinetic fluid motors or pumps – With passage in blade – vane – shaft or rotary distributor...
Reexamination Certificate
2001-09-28
2003-09-02
Look, Edward K. (Department: 3745)
Rotary kinetic fluid motors or pumps
With passage in blade, vane, shaft or rotary distributor...
C415S175000
Reexamination Certificate
active
06612806
ABSTRACT:
This application is the national phase under 35 U.S.C. §371 of PCT International Application No. PCT/EP00/02348 which has an International filing date of Mar. 16, 2000, which designated the United States of America, the entire contents of which are hereby incorporated by reference.
FIELD OF THE INVENTION
The invention relates to a turbomachine with a coolable arrangement, having a first wall element and having a second wall element. In addition, the invention relates to a method of using a coolant to cool an arrangement in a turbomachine, having a first wall element and having a second wall element, which bounds the first wall element.
BACKGROUND OF THE INVENTION
In a turbomachine, for example in a gas turbine, useful work is recovered from a flow of hot working fluid, for example hot gas, as a result of its expansion. With a view to increasing the efficiency of a turbomachine, attempts are made inter alia to achieve the highest possible temperature of the hot working fluid. The components directly subjected to the hot working fluid are therefore subjected to very severe thermal effects. In the case of a gas turbine, this affects, for example, the turbine blading (guide blades and rotor blades) and the turbine wall elements which bound the space with the flow of hot working fluid. For these components, therefore, it is necessary to find suitable materials which have sufficient strength at the highest possible temperatures, and to develop methods by way of which cooling of these components is possible in order to permit the high temperatures to be employed.
In a gas turbine, the coolant necessary for the cooling is usually extracted, as cooling air, from a compressor coupled to the turbine. In order to keep the efficiency loss associated with this extraction of cooling air as small as possible, cooling concepts are intensively sought which ensure the most efficient possible employment of the coolant.
The U.S. Pat. No. 4,642,024 describes a coolable gas turbine engine stator group. The stator group has an outer air seal, together with an upstream restraint and a downstream restraint. The restraints support the outer air seal by means of hook arrangements along a flow path for working medium. This produces a design division of the air seal into three parts, into an upstream and a downstream boundary region and a central region arranged between the boundary regions. In order to cool the outer air seal with cooling air, impingement cooling takes place first in the central region. The boundary regions, which cannot be directly subjected to cooling air because of the restraints, are cooled by a part of the cooling air collected being guided through the restraints in order to permit impingement cooling of the boundary regions. For this purpose, metering holes extend through the restraints in order to guide the cooling air to the upstream and downstream boundary regions of the same outer air seal.
DE 197 33 148 C1 reveals a cooling appliance for cooling, by way of cooling air, a first stage of a gas turbine having a first guide blade and a first rotor blade. The first guide blade has a platform, which represents a wall element, which bounds the flow duct with a hot working fluid. A first chamber and a second chamber, which bounds it in the flow direction, are located on the platform of the first guide blade. A wall, which is inserted in the platform of the guide blade, is arranged between these two chambers. The first chamber is supplied with a first cooling air flow from a first cooling air supply system by way of a first cooling air supply line. The first cooling air flow is guided through the platform and released via the first stage of the gas turbine into the flow duct. The second chamber is correspondingly supplied with a second cooling air flow by a second cooling air supply system by way of a second cooling air supply line, which second cooling air flow is subsequently released through the platform into the first stage and into the flow duct. In this arrangement, the first cooling air supply system is operated with compressor outlet air with a first pressure whereas the second cooling air supply system is operated with compressor air from the compressor at a second pressure from an appropriate extraction point, the second pressure being lower than the first pressure. In this way, the guide blade is subjected to and cooled by independent coolant flows with different pressures.
The U.S. Pat. No. 4,177,004 describes a coolable guide blade cascade support structure of a first stage (inlet stage) of a turbine, in particular a gas turbine. A first guide blade with a blade platform and a guide ring are sequentially arranged on the guide blade cascade support structure, the guide blade ring being at an axial distance from the blade platform, thus forming a gap. During operation of the turbine, the blade platform and the guide ring form the outer boundary for a hot gas driving the rotor of the turbine. The arrangement is cooled by cooling air from a compressor connected upstream of the turbine, the guide blade, which is hollow on the inside, being first subjected to cooling air via the blade platform and, after the cooling of the internal space, the cooling air is released into the hot gas duct via outlet openings in the blade. A partial flow of cooling air is supplied from the blade platform to the guide ring for impingement cooling via an intermediate region which bridges over the gap. A large coolant requirement is indicated by the premature release of the coolant after the blade cooling and by the leakage losses due to the emergence of coolant through the gap into the hot gas duct.
SUMMARY OF THE INVENTION
The object of the invention is to provide a turbomachine with a coolable arrangement, having a first wall element and having a second wall element. This arrangement is, in particular, intended to improve the cooling efficiency. A second object: of the invention is to provide a method of cooling an arrangement, having a first wall element and having a second wall element, in a turbomachine.
According to the invention, the object mentioned first is achieved by a turbomachine with a coolable arrangement, having a first wall element and having a second wall element, which bounds the first wall element along a longitudinal axis, each wall element having a wall with a first boundary region bounding the wall along the longitudinal axis and having a second boundary region, which is opposite to the first boundary region along the longitudinal axis, and having a hot surface, which can be exposed to a hot working fluid, and in which arrangement, a first cooling region, which faces away from the hot surface and which can be subjected to a coolant, is associated with the first wall element, and a second cooling region, which faces away from the hot surface, is associated with the second wall element, in which arrangement the first cooling region and the second cooling region have a flow connection with one another, in such a way that the coolant passes from the first cooling region into the second cooling region, while avoiding leakage losses.
The invention is based on consideration of the fact that a wall element in a turbomachine, which wall element is subjected to a hot working fluid, for example a hot gas or steam, is subjected to very severe thermal effects due to the temperature of the working fluid. In this arrangement, a wall element is used for bounding the space through which the hot working fluid flows. Using known cooling mechanisms, this wall element can be subjected to a coolant in a cooling region in order to cool the hot surface of the wall element which can be exposed to the hot working fluid. In the process, heat transfer occurs from the hot surface into the cooling region which faces away from the hot surface and in which the coolant absorbs the heat and removes it. In the process, the coolant is heated more or less strongly, depending on the cooling mechanism selected, the duration of the heat absorption by the coolant and the temperature difference between the hot surface
Bolms Hans-Thomas
Tiemann Peter
Harness & Dickey & Pierce P.L.C.
Look Edward K.
McCoy Kimya N
Siemens Aktiengesellschaft
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