Patent Description:
The turbine is configured so that a high-temperature and high-pressure working medium (for example, a supercritical CO<NUM> medium) is introduced into a turbine casing, to thereby cause a turbine rotor to rotate. Here, there has been proposed to provide a cooling medium flow path through which a cooling medium flows in the turbine rotor, or the like, in consideration of heat resistance. Then, there has also been proposed to provide a throttle mechanism such as a flow rate regulating plug in order to regulate the flow rate of the cooling medium flowing through the cooling medium flow path.

In the turbine where the pressure ratio between an initial stage and a final stage changes significantly between a rated operation time and a startup time (such as a CO<NUM> turbine into which a supercritical CO<NUM> medium is introduced as the working medium), the temperature of a passage part through which the working medium flows becomes high after ignition, making it necessary to cool each part of the configuration appropriately. The turbine stage located downstream has a large differential pressure between the working medium and the cooling medium, making it necessary to increase the pressure loss for regulating the flow rate. Therefore, when the pressure loss is adjusted to the conditions at a rated operation time with a large differential pressure, the cooling medium does not easily flow to the turbine stage located downstream at a startup time with a small differential pressure, resulting in that the cooling medium supply may not occur in some cases. Therefore, changing the cross-sectional area of the flow path (cooling medium flow path) through which the fluid of the cooling medium flows by the throttle mechanism according to the operating state of the turbine is required.

However, for example, when a valve is installed in a pipe as the throttle mechanism and the valve is driven by an actuator to change the cross-sectional area of the flow path in the pipe, the configuration becomes more complex and an installation space for installing the pipe is required. Further, when the above-described pipe needs to be installed to penetrate through the turbine casing, leakage of the working medium may occur in the portion where the pipe penetrates, and at the same time, the cost may increase as a result of the installation.

Due to the above-described circumstances, it is not easy to change the cross-sectional area of the flow path according to the operating state in the past.

Therefore, the problem to be solved by the present invention is to provide a throttle mechanism that are capable of easily changing a cross-sectional area of a flow path according to an operating state.

<CIT> discloses a throttle mechanism for controlling a flow rate of a fluid flowing through a flow path, comprising a first flow path forming member in which a first through hole forming the flow path is formed and a second flow path forming member in which a second through hole forming the flow path is formed, wherein the throttle mechanism is configured to make the cross-sectional area of the flow path change autonomously according to temperature. Further documents disclosing a throttle mechanism configured to make the cross-sectional area of the flow path change autonomously according to temperature are disclosed in <CIT> and <CIT>.

The above problem is according to the invention solved by a throttle mechanism as defined in claim <NUM>.

A throttle mechanism in an embodiment is a throttle mechanism that controls a flow rate of a fluid flowing through a flow path, and is configured to make a cross-sectional area of the flow path change autonomously according to temperature.

There is explained a configuration of a throttle mechanism using <FIG>.

A throttle mechanism <NUM> includes, as illustrated in <FIG>, a pipe-shaped member <NUM>, a rod-shaped member <NUM>, and a support member <NUM>, and controls a flow rate of a fluid (such as a cooling medium) flowing through a flow path (such as a cooling medium flow path). Here, the throttle mechanism <NUM> is configured to make a cross-sectional area of the flow path (flow path area) change autonomously according to temperature. <FIG> illustrates a cross section in a plane orthogonal to the axial direction of the pipe-shaped member <NUM> and the rod-shaped member <NUM>. There are sequentially explained parts configuring the throttle mechanism <NUM>.

In the throttle mechanism <NUM>, the pipe-shaped member <NUM> is, for example, a cylindrical pipe-shaped body. The pipe-shaped member <NUM> includes thereinside an internal space SP51 forming a flow path such as a cooling medium flow path.

The rod-shaped member <NUM> is installed in the internal space SP51 of the pipe-shaped member <NUM>. Here, the rod-shaped member <NUM> is, for example, a cylindrical rod-shaped body and is arranged to be coaxial with the pipe-shaped member <NUM>.

The support member <NUM> is provided to support the rod-shaped member <NUM> in the internal space SP51 of the pipe-shaped member <NUM>. Here, the support member <NUM> is a plurality of rod-shaped bodies, each of which has one end thereof connected to an inner peripheral surface of the pipe-shaped member <NUM> and has the other end thereof connected to an outer peripheral surface of the rod-shaped member <NUM>.

The linear expansion coefficient of the material forming the pipe-shaped member <NUM> and the linear expansion coefficient of the material forming the rod-shaped member <NUM> are different from each other. Therefore, the distance between the pipe-shaped member <NUM> and the rod-shaped member <NUM> varies according to temperature in the throttle mechanism <NUM>. As a result, the cross-sectional area in a plane orthogonal to the axial directions of the pipe-shaped member <NUM> and the rod-shaped member <NUM> changes in the flow path.

Specifically, when the linear expansion coefficient of the material forming the rod-shaped member <NUM> is larger than that of the material forming the pipe-shaped member <NUM>, the distance between the inner peripheral surface of the pipe-shaped member <NUM> and the outer peripheral surface of the rod-shaped member <NUM> becomes narrower because the rod-shaped member <NUM> expands more than the pipe-shaped member <NUM> as temperature rises. As a result, the cross-sectional area of the flow path decreases. One example of the materials in this case is as follows. In this case, the linear expansion coefficient of the support member <NUM> is preferred to be closer to that of the rod-shaped member <NUM> than to that of the pipe-shaped member <NUM> (this is because in the opposite case, stress is generated at a root portion by tension).

On the other hand, when the linear expansion coefficient of the material forming the rod-shaped member <NUM> is smaller than that of the material forming the pipe-shaped member <NUM>, the distance between the inner peripheral surface of the pipe-shaped member <NUM> and the outer peripheral surface of the rod-shaped member <NUM> becomes wider because the rod-shaped member <NUM> contracts more than the pipe-shaped member <NUM> as temperature falls. As a result, the cross-sectional area of the flow path increases. One example of the materials in this case is as follows. In this case, the linear expansion coefficient of the support member <NUM> is preferred to be closer to that of the pipe-shaped member <NUM> than to that of the rod-shaped member <NUM> (this is because in the opposite case, stress is generated at a root portion by tension).

As above, the throttle mechanism <NUM> is configured to make the cross-sectional area of the flow path change autonomously according to temperature. Therefore, changing the cross-sectional area of the flow path can easily be achieved when temperature changes according to the operating state of the turbine, for example.

There is explained a throttle mechanism using <FIG>.

A throttle mechanism <NUM> includes, as illustrated in <FIG>, a pipe-shaped member <NUM>, a rod-shaped member <NUM>, and a support member <NUM> similarly to the first example, and controls a flow rate of a fluid (such as a cooling medium) flowing through a flow path (such as a cooling medium flow path). Here, the throttle mechanism <NUM> is configured to make a cross-sectional area of the flow path change autonomously according to temperature. <FIG> illustrates a top surface in a plane orthogonal to the axial direction of the pipe-shaped member <NUM> and the rod-shaped member <NUM>. <FIG> illustrates a cross section in a plane along the axial direction of the pipe-shaped member <NUM> and the rod-shaped member <NUM>.

In the throttle mechanism <NUM>, an internal space SP51 of the pipe-shaped member <NUM> has, for example, a truncated conical shape, and its cross-sectional area becomes narrower from one end (lower end) to the other end (upper end) in the axial direction of the pipe-shaped member <NUM> and the rod-shaped member <NUM>.

The rod-shaped member <NUM> is arranged to be coaxial with the internal space SP51 of the pipe-shaped member <NUM> in the internal space SP51 of the pipe-shaped member <NUM>.

The throttle mechanism <NUM> is configured so that as the support member <NUM> expands or contracts according to temperature, the rod-shaped member <NUM> moves in the internal space SP51 and the distance between the pipe-shaped member <NUM> and the rod-shaped member <NUM> varies, and thereby the cross-sectional area of the flow path changes.

For example, when temperature rises, the support member <NUM> expands with the rise in temperature, and the rod-shaped member <NUM> moves upward in the internal space SP51. Thereby, as can be seen from <FIG>, the distance between the inner peripheral surface of the pipe-shaped member <NUM> and the outer peripheral surface of the rod-shaped member <NUM> becomes short, resulting in a smaller cross-sectional area of the flow path. In contrast to this, when temperature falls, the support member <NUM> contracts with the fall in temperature, and the rod-shaped member <NUM> moves downward in the internal space SP51. Thereby, as can be seen from <FIG>, the distance between the inner peripheral surface of the pipe-shaped member <NUM> and the outer peripheral surface of the rod-shaped member <NUM> becomes long, resulting in a larger cross-sectional area of the flow path.

Regarding the linear expansion coefficient, the linear expansion coefficient of the rod-shaped member <NUM> and the support member <NUM> is preferably larger than that of the pipe-shaped member <NUM>. When only the support member <NUM> expands, the cross-sectional area of the flow path becomes small because the rod-shaped member <NUM> is pushed up. Further, when only the rod-shaped member <NUM> expands, as in the first example, the cross-sectional area of the flow path between the rod-shaped member <NUM> and the pipe-shaped member <NUM> becomes small.

The throttle mechanism <NUM> may be configured to make the cross-sectional area of the flow path large as temperature rises and make the cross-sectional area of the flow path small as temperature falls. This configuration, though not illustrated, can be fabricated by forming, for example, the internal space SP51 of the pipe-shaped member <NUM> so that its cross-sectional area increases from one end (lower end) to the other end (upper end) in the axial direction of the pipe-shaped member <NUM> and the rod-shaped member <NUM> (see <FIG>). In this case, the relationship of the linear expansion coefficient is preferably opposite to the above-described relationship.

As above, the throttle mechanism <NUM> is configured to make the cross-sectional area of the flow path change autonomously according to temperature in the same manner as in the first example. Therefore, in this example as well, changing the cross-sectional area of the flow path can easily be achieved when temperature changes according to the operating state of the turbine, for example.

There is explained a configuration of a throttle mechanism according to an embodiment in accordance with the invention using <FIG> and <FIG>.

A throttle mechanism <NUM> in this embodiment includes, unlike the first example, a first flow path forming member <NUM>, a second flow path forming member <NUM>, and a biasing member <NUM> as illustrated in <FIG> and <FIG>, and controls a flow rate of a fluid (such as a cooling medium) flowing through a flow path (such as a cooling medium flow path). The first flow path forming member <NUM> includes a first through hole H61 forming the flow path, and the second flow path forming member <NUM> includes a second through hole H62 forming the flow path. Here, the throttle mechanism <NUM> is configured to make a cross-sectional area of the flow path change autonomously according to temperature. <FIG> illustrates a cross section in a plane orthogonal to the center axis direction of the first through hole H61 and the second through hole H62. <FIG> illustrates a top surface in a plane along the center axis direction of the first through hole H61 and the second through hole H62.

In the throttle mechanism <NUM> in this embodiment, the first flow path forming member <NUM> includes a plate-shaped body portion <NUM> and a projecting portion <NUM>. In the plate-shaped body portion <NUM> of the first flow path forming member <NUM>, the first through hole H61 is formed. Of the first flow path forming member <NUM>, the projecting portions <NUM> are paired and are provided at both ends on the upper surface of the plate-shaped body portion <NUM>. In the first flow path forming member <NUM>, in which a rectangular-shaped trench T61 (recessed portion) is interposed between a pair of the projecting portions <NUM> on the upper surface of the plate-shaped body portion <NUM>, the trench T61 is located above the first through hole H61 in line with the first through hole H61 in the center axis direction of the cylindrical-shaped first through hole H61 and communicates with the first through hole H61.

The second flow path forming member <NUM> is a plate-shaped body, in which the second through hole H62 forming the flow path with the first through hole H61 is formed. In the second flow path forming member <NUM>, the second through hole H62 has a cylindrical shape, and for example, the inside diameter of the second through hole H62 is larger than that of the first through hole H61. Further, the second flow path forming member <NUM> is movably installed inside the trench T61 of the first flow path forming member <NUM>. The width in the moving direction in the second flow path forming member <NUM> is narrower than that in the moving direction in the trench T61 of the first flow path forming member <NUM>.

The biasing member <NUM> is, for example, a spring and is installed inside the trench T61 to bias the second flow path forming member <NUM> in the moving direction of the second flow path forming member <NUM>. Here, the biasing member <NUM> includes a first biasing member <NUM> and a second biasing member <NUM>.

The first biasing member <NUM> is installed inside the trench T61 on one side (left side) in the moving direction of the second flow path forming member <NUM>. The second biasing member <NUM> is installed inside the trench T61 on the other side (right side) in the moving direction of the second flow path forming member <NUM>.

The material that forms the first biasing member <NUM> and the material that forms the second biasing member <NUM> are different from each other in the tendency that a Young's modulus changes according to temperature. Therefore, the size of an overlapping portion of the first through hole H61 and the second through hole H62 varies as the second biasing member <NUM> moves inside the trench T61 according to temperature. As a result, the cross-sectional area of the flow path formed by the first through hole H61 and the second through hole H62 changes.

The material forming the second biasing member <NUM> is made larger than the material forming the first biasing member <NUM> in the rate at which the Young's modulus changes as temperature rises from one temperature to another temperature, for example. This causes the balance between a pressing force of the first biasing member <NUM> and a pressing force of the second biasing member <NUM> to change as temperature rises, and the overlapping portion of the first through hole H61 and the second through hole H62 becomes small, and thereby, the cross-sectional area of the flow path becomes small. Then, as temperature falls, the overlapping portion of the first through hole H61 and the second through hole H62 becomes large, and thereby the cross-sectional area of the flow path becomes large.

<FIG> is a view illustrating one example of characteristics of the first biasing member <NUM> and the second biasing member <NUM> in the throttle mechanism <NUM> according to the embodiment. In <FIG>, the horizontal axis indicates a temperature t and the vertical axis indicates a Young's modulus E.

As illustrated in <FIG>, the first biasing member <NUM> and the second biasing member <NUM> are different from each other in the relationship between the temperature and the Young's modulus. Here, the Young's modulus E at a temperature t0 is higher in the second biasing member <NUM> than in the first biasing member <NUM>, and there is a difference d0 between the Young's modulus E of the first biasing member <NUM> and the Young's modulus E of the second biasing member <NUM>. Then, the Young's modulus E at temperature t1, which is higher than the temperature t0, is lower in the second biasing member <NUM> than in the first biasing member <NUM>, and there is a difference d1 between the Young's modulus E of the first biasing member <NUM> and the Young's modulus E of the second biasing member <NUM>. As described above, when the temperature changes from the temperature t0 to the temperature t1, the differences d0 and d1 between the Young's modulus E of the first biasing member <NUM> and the Young's modulus E of the second biasing member <NUM> change. As a result, there is generated a difference also between a biasing force of the first biasing member <NUM> and a biasing force of the second biasing member <NUM> according to temperature, so that the second flow path forming member <NUM> moves with respect to the first flow path forming member <NUM>.

The throttle mechanism <NUM> may be configured to make the cross-sectional area of the flow path large as temperature rises and make the cross-sectional area of the flow path small as temperature falls. This configuration, though not illustrated, can be fabricated by configuring the throttle mechanism <NUM> so that, for example, the overlapping portion of the first through hole H61 and the second through hole H62 becomes large from the state where the overlapping portion is small as temperature rises.

As above, the throttle mechanism <NUM> in this embodiment is configured to make the cross-sectional area of the flow path change autonomously according to temperature in the same manner as in the first example. Therefore, in this embodiment as well, changing the cross-sectional area of the flow path can easily be achieved when temperature changes according to the operating state of the turbine, for example.

In the above-described embodiment, the characteristics of the first biasing member <NUM> and the second biasing member <NUM> are illustrated in <FIG>, but they are not limited to these.

<FIG> and <FIG> are views each illustrating one example of characteristics of a first biasing member <NUM> and a second biasing member <NUM> in a throttle mechanism according to a modified example of the embodiment. In <FIG> and <FIG>, the horizontal axis indicates the temperature t and the vertical axis indicates the Young's modulus E.

As illustrated in <FIG>, the Young's modulus E at the temperature t1 higher than the temperature t0 may be higher in the second biasing member <NUM> than in the first biasing member <NUM> unlike the case of <FIG>. Further, as illustrated in <FIG>, the Young's modulus E of the second biasing member <NUM> may vary in the rate at which the Young's modulus E changes as temperature rises between the temperature t0 and the temperature t1. Similarly to the Young's modulus E of the second biasing member <NUM>, though not illustrated, the Young's modulus E of the first biasing member <NUM> may also vary in the rate at which the Young's modulus E changes as temperature rises between the temperature t0 and the temperature t1. Even in such a case, when the temperature changes from t0 to <NUM>, the differences d0, d1 between the Young's modulus E of the first biasing member <NUM> and the Young's modulus E of the second biasing member <NUM> change, and the biasing force of the first biasing member <NUM> and the biasing force of the second biasing member <NUM> also differ from each other according to temperature. Therefore, the second flow path forming member <NUM> moves with respect to the first flow path forming member <NUM>.

Further, in the above-described embodiment, there has been explained as an example the case where the first through hole H61 and the second through hole H62 have a circular shape, but the present invention is not limited to this.

<FIG> and <FIG> are top views each schematically illustrating a configuration of the throttle mechanism according to the modified example of the embodiment.

As illustrated in <FIG>, the first through hole H61 and the second through hole H62 may have a rectangular shape, for example. Having a rectangular shape, the first through hole H61 and the second through hole H62 can be designed easily because it is easy to calculate the area where the first and second through holes overlap.

Besides, as illustrated in <FIG>, the first through hole H61 may be formed to be wider at the sides than at the center in the moving direction. As a result, the change in the area can be made larger than in the case of <FIG>.

<FIG> is a view schematically illustrating an entire configuration of a power generation system.

As illustrated in <FIG>, the power generation system is configured to generate power using a supercritical working medium (working CO<NUM> medium). There are sequentially explained respective parts configuring the power generation system.

In the power generation system, a supercritical working medium is supplied to a turbine <NUM> from a combustor <NUM>. Then, the working medium expands and performs work in the turbine <NUM>, which causes a rotating shaft of the turbine <NUM> to rotate. The medium exhausted from turbine <NUM> flows to a regenerative heat exchanger <NUM>.

A power generator <NUM> is configured to generate power by driving the turbine <NUM>. Here, a rotating shaft of the power generator <NUM> is coupled to the rotating shaft of the turbine <NUM>, and the rotation of the rotating shaft of the turbine <NUM> causes the rotating shaft of the power generator <NUM> to rotate, and thereby power is generated in the power generator <NUM>.

The medium exhausted from the turbine <NUM> and a medium discharged from a CO<NUM> pump <NUM> flow into the regenerative heat exchanger <NUM>, where heat exchange is performed between the two. Here, the medium exhausted from the turbine <NUM> is cooled by the heat exchange in the regenerative heat exchanger <NUM>. On the other hand, the medium discharged from the CO<NUM> pump <NUM> is heated by the heat exchange in the regenerative heat exchanger <NUM> to be supplied to the combustor <NUM>.

In a cooler <NUM>, the medium, which is exhausted from the turbine <NUM> and then is subjected to heat exchange in the regenerative heat exchanger <NUM>, is cooled. Thereby, in the cooler <NUM>, water vapor contained in the medium discharged from the regenerative heat exchanger <NUM> is condensed.

The medium discharged from the cooler <NUM> is supplied to a moisture separator <NUM>. The moisture separator <NUM> separates water (liquid-phase water) generated by the condensation in the cooler <NUM> from the supplied medium. The separated water is discharged to the outside from the moisture separator <NUM>. Therefore, in the moisture separator <NUM>, a medium containing high-purity CO<NUM> can be obtained.

The CO<NUM> pump <NUM> receives the medium being high-purity CO<NUM> supplied from the moisture separator <NUM> to boost the supplied medium to a supercritical pressure. A portion of the medium boosted by the CO<NUM> pump <NUM> is discharged to the outside to be used for storage, enhanced oil recovery, or the like, for example. Here, for example, CO<NUM> corresponding to the amount of CO<NUM> increased by combustion in the combustor <NUM> is discharged to the outside. Then, the rest of the medium boosted by the CO<NUM> pump <NUM> is supplied to the regenerative heat exchanger <NUM> and heated as described above.

A portion of the medium extracted from the middle of the regenerative heat exchanger <NUM> is supplied to the turbine <NUM> as a cooling medium (cooling CO<NUM> medium). Then, the rest of the medium that has passed through the regenerative heat exchanger <NUM> is led to the combustor <NUM>. In other words, in the regenerative heat exchanger <NUM>, the medium boosted by the CO<NUM> pump <NUM> is heated by heat exchange with the medium exhausted from the turbine <NUM> and then flows into the combustor <NUM>. To the combustor <NUM>, a fuel is supplied from the outside and oxygen is supplied from an oxygen generator <NUM>. In the combustor <NUM>, a combustion gas is generated by combustion, and a supercritical working medium containing the combustion gas is discharged.

There is explained one example of the turbine <NUM> using <FIG> and <FIG>.

<FIG> schematically illustrates a side surface of the turbine <NUM>. <FIG> schematically illustrates a partial cross section of the turbine <NUM>. In <FIG>, the longitudinal direction is a vertical direction z, the lateral direction is a first horizontal direction x, and the direction vertical to the paper surface is a second horizontal direction y. <FIG> schematically illustrates a partial cross section (mainly a cross section on the upper half side) of a vertical plane (xz plane).

In the turbine <NUM>, as illustrated in <FIG>, a working medium F is introduced into the inside via a combustor casing <NUM>.

As illustrated in <FIG>, the turbine <NUM> includes a turbine rotor <NUM>, a turbine casing <NUM>, and a turbine stage <NUM>. The turbine <NUM> is of a multistage type, in which a plurality of the turbine stages <NUM> are arranged side by side in an axial direction (x) along a rotation center axis AX of the turbine rotor <NUM>. In the turbine <NUM>, the working medium F is introduced into an inner casing <NUM> housed in an outer casing <NUM> of the turbine casing <NUM> via a transition piece <NUM>. Then, the introduced working medium F works sequentially in a plurality of the turbine stages <NUM> arranged side by side from an upstream side Us to a downstream side Ds.

Thereafter, the working medium F is discharged to the outside of the turbine casing <NUM> through an exhaust pipe <NUM>, as illustrated in <FIG>.

There are sequentially explained in detail parts configuring the turbine <NUM>.

The turbine rotor <NUM> is a rod-shaped body, and is supported to be rotatable by a bearing (not illustrated) so that the rotation center axis AX is along the first horizontal direction x. At the turbine rotor <NUM>, a plurality of rotor wheels <NUM> are provided on the outer peripheral surface. A plurality of the rotor wheels <NUM> are arrayed side by side in the axial direction (x) along the rotation center axis AX. Though not illustrated in <FIG>, the turbine rotor <NUM> is coupled to the power generator.

The turbine casing <NUM> has a double-casing structure including the inner casing <NUM> and the outer casing <NUM>.

In the turbine casing <NUM>, the inner casing <NUM> is installed around the turbine rotor <NUM> in a manner to surround a plurality of the turbine stages <NUM>.

In the turbine casing <NUM>, the outer casing <NUM> is configured to house the turbine rotor <NUM> via the inner casing <NUM>.

Further, in the outer casing <NUM>, a packing head <NUM> is installed on the downstream side Ds from the final-stage turbine stage <NUM> and at an inner portion in the radial direction. Here, a final-stage wheel space RW intervenes between the packing head <NUM> and the final-stage rotor wheel <NUM> in the axial direction.

The turbine stage <NUM> includes a stator blade cascade composed of a plurality of stator blades <NUM> (nozzle blades), and a rotor blade cascade composed of a plurality of rotor blades <NUM>. The turbine stage <NUM> is composed of the stator blade cascade and the rotor blade cascade adjacent to the stator blade cascade on the downstream side Ds, and a plurality of the turbine stages <NUM> are arranged side by side in the axial direction along the rotation center axis AX.

A plurality of the stator blades <NUM> (nozzle blades) forming the stator blade cascade are supported inside the inner casing <NUM>. A plurality of the stator blades <NUM> are arrayed in a rotation direction R in a manner to surround the turbine rotor <NUM> between an inner shroud <NUM> and an outer shroud <NUM>.

A plurality of the rotor blades <NUM> forming the rotor blade cascade are arrayed in the rotation direction R in a manner to surround the turbine rotor <NUM> inside the inner casing <NUM>. In the rotor blade <NUM>, an implanted part <NUM> is provided at an inner portion in the radial direction. The implanted part <NUM> is fitted on the outer peripheral surface of the rotor wheel <NUM> of the turbine rotor <NUM>. The outer periphery of the rotor blade <NUM> is surrounded by a shroud segment <NUM>. The shroud segment <NUM> is supported by the outer shroud <NUM>.

At a portion of the outer peripheral surface of the turbine rotor <NUM>, facing the stator blade <NUM>, for example, a heat insulating piece <NUM> is provided. Here, the heat insulating piece <NUM> is supported by a portion of the outer peripheral surface of the turbine rotor <NUM>, facing the inner peripheral surface of the inner shroud <NUM>. The heat insulating piece <NUM> is provided to insulate heat between a main flow path through which the working medium F flows inside the turbine casing <NUM> and the turbine rotor <NUM>.

The heat insulating piece <NUM> includes a heat insulating plate <NUM> and a leg part <NUM>, and the heat insulating plate <NUM> and the leg part <NUM> are provided in sequence as going from the outer side to the inner side in the radial direction of the turbine rotor <NUM>.

In the heat insulating piece <NUM>, the heat insulating plate <NUM> includes a portion extending along the rotation center axis AX of the turbine rotor <NUM>. The heat insulating plate <NUM> is installed to have a gap intervening between the outer peripheral surface of the heat insulating plate <NUM> and the inner peripheral surface of the inner shroud <NUM> and have a space intervening between the inner peripheral surface of the heat insulating plate <NUM> and the outer peripheral surface of the turbine rotor <NUM>. The leg part <NUM> extends in the radial direction of the turbine rotor <NUM>, and an engagement part 72a is formed on the inner side in the radial direction in the leg part <NUM>. The engagement part 72a is engaged with the turbine rotor <NUM>.

In order to seal a clearance between the inner peripheral surface of the stator blade <NUM> and the outer peripheral surface of the heat insulating plate <NUM>, a seal fin <NUM> is provided as necessary. Further, in order to seal a clearance between the outer peripheral surface of the rotor blade <NUM> and the inner peripheral surface of the shroud segment <NUM> provided in the inner casing <NUM>, the seal fin <NUM> is provided.

The turbine <NUM> includes an upstream-side gland part G1 and a downstream-side gland part G2.

The upstream-side gland part G1 is one end portion located on the upstream side Us of the working medium F of both end portions where the turbine stage <NUM> is not arranged in the axial direction in the turbine <NUM>. The downstream-side gland part G2 is one end portion located on the downstream side Ds of the working medium F of both the end portions where the turbine stage <NUM> is not arranged in the axial direction in the turbine <NUM>. In other words, a portion where the turbine stages <NUM> are arranged in the axial direction in the turbine <NUM> is sandwiched between the upstream-side gland part G1 and the downstream-side gland part G2.

In the upstream-side gland part G1 and the downstream-side gland part G2, gland sealing parts 35a, 35b, and 35c are installed. The gland sealing parts 35a, 35b, and 35c are provided to seal a clearance between a rotary body including the turbine rotor <NUM> and a stationary body including the turbine casing <NUM>.

Specifically, a plurality of the gland sealing parts 35a are installed on the inner peripheral surface of the outer casing <NUM> in a manner to seal a clearance between the inner peripheral surface of the outer casing <NUM> and the outer peripheral surface of the turbine rotor <NUM> in the upstream-side gland part G1. A plurality of the gland sealing parts 35b are installed on the inner peripheral surface of the inner casing <NUM> in a manner to seal a clearance between the inner peripheral surface of the inner casing <NUM> and the outer peripheral surface of the turbine rotor <NUM> in the upstream-side gland part G1. Further, a plurality of the gland sealing parts 35c are installed on the inner peripheral surface of the packing head <NUM> in a manner to seal a clearance between the inner peripheral surface of the packing head <NUM> installed in the inner casing <NUM> and the outer peripheral surface of the turbine rotor <NUM> in the downstream-side gland part G2.

The gland sealing parts 35a, 35b, and 35c are each configured to include, for example, a labyrinth fin. Other than that, the gland sealing parts 35a, 35b, and 35c may be formed of various seal structures such as a brush seal, a leaf seal, an abradable seal, and a honeycomb seal.

The transition piece <NUM> includes a portion extending in the radial direction in a manner to penetrate the outer casing <NUM> and the inner casing <NUM> from above the turbine casing <NUM>. The transition piece <NUM> is coupled to the initial-stage turbine stage <NUM> so as to introduce the working medium F into the initial-stage turbine stage <NUM>.

A cooling medium introduction pipe <NUM> extends, similarly to the transition piece <NUM>, in the radial direction in a manner to penetrate the outer casing <NUM> and the inner casing <NUM> from above the turbine casing <NUM>. The cooling medium introduction pipe <NUM> is installed in a manner to surround a portion extending in the radial direction in the transition piece <NUM>. The inside diameter of the cooling medium introduction pipe <NUM> is larger than the outside diameter of the portion extending in the radial direction in the transition piece <NUM>, and a cooling medium CF flows between the inner peripheral surface of the cooling medium introduction pipe <NUM> and the outer peripheral surface of the portion extending in the radial direction in the transition piece <NUM>. The cooling medium CF having flowed between the cooling medium introduction pipe <NUM> and the transition piece <NUM> is introduced into a cooling chamber R31a formed in a manner to surround, in the rotation direction R, the turbine rotor <NUM> inside the inner casing <NUM>.

In the inner casing <NUM>, an inner casing cooling medium flow path H31 is formed through which the cooling medium CF flows. The inner casing cooling medium flow path H31 is provided to supply the cooling medium CF to the stator blade <NUM> of the turbine stage <NUM>. Here, the inner casing cooling medium flow path H31 includes a first inner casing cooling medium flow path part H311 and a second inner casing cooling medium flow path part H312.

The first inner casing cooling medium flow path part H311 is a hole along the axial direction of the turbine rotor <NUM>, and has one end thereof, which is located on the upstream side Us of the working medium F, communicating with the cooling chamber R31a.

The second inner casing cooling medium flow path part H312 is a hole along the radial direction of the turbine rotor <NUM> and is formed on the inner side relative to the first inner casing cooling medium flow path part H311 in the radial direction. The second inner casing cooling medium flow path part H312 has one end thereof, which is located on the outer side in the radial direction, communicating with the first inner casing cooling medium flow path part H311. In contrast to this, the other end of the second inner casing cooling medium flow path part H312, which is located on the inner side in the radial direction, communicates with the stator blade <NUM> via the outer shroud <NUM>.

The inner casing cooling medium flow path H31 is provided one each, for example, on the upper half side and the lower half side in the turbine <NUM>. A plurality of the inner casing cooling medium flow paths H31 are preferably provided at regular intervals in the rotation direction R.

In the turbine rotor <NUM>, a rotor cooling flow path H21 is formed through which the cooling medium CF flows. The rotor cooling flow path H21 is configured so that the cooling medium CF flows from the cooling chamber R31a to the space located between the inner peripheral surface of the heat insulating plate <NUM> and the outer peripheral surface of the turbine rotor <NUM>. Here, the rotor cooling flow path H21 includes a first rotor cooling flow path part H211, a second rotor cooling flow path part H212, and a third rotor cooling flow path part H213.

The first rotor cooling flow path part H211 is a hole along the radial direction of the turbine rotor <NUM>. The first rotor cooling flow path part H211 has one end thereof, which is located on the outer side in the radial direction, communicating with the cooling chamber R31a. In contrast to this, the other end of the first rotor cooling flow path part H211, which is located on the inner side in the radial direction, communicates with the second rotor cooling flow path part H212.

The second rotor cooling flow path part H212 is a hole along the axial direction of the turbine rotor <NUM>, and provided coaxially with the rotation center axis AX of the turbine rotor <NUM>.

The third rotor cooling flow path part H213 is a hole along the radial direction of the turbine rotor <NUM>. The third rotor cooling flow path part H213 has one end thereof, which is located on the inner side in the radial direction, communicating with the second rotor cooling flow path part H212. In contrast to this, the other end of the third rotor cooling flow path part H213, which is located on the outer side in the radial direction, communicates with the space located between the inner peripheral surface of the heat insulating plate <NUM> and the outer peripheral surface of the turbine rotor <NUM>. The third rotor cooling flow path part H213 is provided to correspond to each of a plurality of the turbine stages <NUM>.

In the turbine <NUM>, throttle mechanisms 50a are provided. The throttle mechanism 50a is provided at the rotor cooling flow path H21 and the inner casing cooling medium flow path H31, which are the cooling medium flow path intended for introducing the cooling medium into the turbine stage <NUM>.

Specifically, the throttle mechanism 50a is not installed at the third rotor cooling flow path part H213 (a first cooling medium flow path part) intended for introducing the cooling medium into the turbine stage <NUM> on the upstream side Us from the final-stage turbine stage <NUM> out of a plurality of the third rotor cooling flow path parts H213 constituting the rotor cooling flow path H21. The throttle mechanism 50a is installed at the third rotor cooling flow path part H213 (a second cooling medium flow path part) intended for introducing the cooling medium into the final-stage turbine stage <NUM> out of a plurality of the third rotor cooling flow path parts H213.

Further, the throttle mechanism 50a is not installed at the second inner casing cooling medium flow path part H312 (first cooling medium flow path part) intended for introducing the cooling medium into the turbine stage <NUM> on the upstream side Us from the final-stage turbine stage <NUM> out of a plurality of the second inner casing cooling medium flow path parts H312 constituting the inner casing cooling medium flow path H31. The throttle mechanism 50a is installed at the second inner casing cooling medium flow path part H312 (second cooling medium flow path part) intended for introducing the cooling medium into the final-stage turbine stage <NUM> out of a plurality of the second inner casing cooling medium flow path parts H312.

The throttle mechanism 50a has the same configuration as that of the throttle mechanism <NUM> in the embodiment and is configured to make the cross-sectional areas of the third rotor cooling flow path part H213 and the second inner casing cooling medium flow path part h312 (second cooling medium flow path part), which are intended for introducing the cooling medium into the final-stage turbine stage <NUM>, small as temperature rises.

The flow of the cooling medium CF in the above-described turbine <NUM> is explained.

In the turbine <NUM>, as illustrated in <FIG>, the cooling medium CF is introduced into the inside of the turbine casing <NUM> from the outside via the combustor casing <NUM>. Here, the cooling medium CF is a medium that has been subjected to cooling or the like after exhausted from the turbine <NUM>, as illustrated in <FIG>, and is introduced into the turbine <NUM> in a state where it is lower in temperature than the working medium F and higher in pressure than the working medium F.

Specifically, the cooling medium CF flows into the inside of the inner casing <NUM> through the cooling medium introduction pipe <NUM> as illustrated in <FIG>. The cooling medium CF is introduced into the cooling chamber R31a provided inside the inner casing <NUM> via the clearance between the outer peripheral surface of the transition piece <NUM> and the inner peripheral surface of the cooling medium introduction pipe <NUM>.

The cooling medium CF introduced into the cooling chamber R31a leaks from the inside to the outside of the turbine casing <NUM> in the upstream-side gland part G1. Specifically, in the upstream-side gland part G1, the cooling medium CF flows from the cooling chamber R31a to the clearance between the inner peripheral surface of the inner casing <NUM> where the gland sealing parts 35b are provided and the outer peripheral surface of the turbine rotor <NUM>. Thereafter, the cooling medium CF flows between the inner peripheral surface of the outer casing <NUM> where the gland sealing parts 35a are provided and the outer peripheral surface of the turbine rotor <NUM>.

Further, the cooling medium CF introduced into the cooling chamber R31a is introduced into the rotor cooling flow path H21 formed in the turbine rotor <NUM>. Here, the cooling medium CF flows through the first rotor cooling flow path part H211, the second rotor cooling flow path part H212, and the third rotor cooling flow path part H213 in sequence in the rotor cooling flow path H21. The cooling medium CF then flows into the space located between the inner peripheral surface of the heat insulating plate <NUM> forming the heat insulating piece <NUM> and the outer peripheral surface of the turbine rotor <NUM>. Then, the cooling medium CF passes through, for example, the clearance between the implanted part <NUM> of the rotor blade <NUM> and the rotor wheel <NUM> and is introduced into the rotor blade <NUM>. Thereby, the turbine rotor <NUM> and the rotor blade <NUM> are cooled. The cooling medium CF introduced into the rotor blade <NUM> is discharged, for example, to the main flow path through which the working medium F flows inside the inner casing <NUM>.

Besides, the cooling medium CF introduced into the cooling chamber R31a passes through the inner casing cooling medium flow path H31 formed in the inner casing <NUM> to be supplied to the stator blade <NUM> in each of a plurality of the turbine stages <NUM>. Specifically, the cooling medium that has flowed into the inner casing cooling medium flow path H31 is introduced into a space provided on the outer side in the radial direction in the outer shroud <NUM>. The space provided on the outer side in the radial direction in the outer shroud <NUM> is a space communicated in a ring shape in the rotation direction R, and communicates with, for example, a cooling hole (not illustrated) formed inside each of the stator blade <NUM> and the inner shroud <NUM>. The cooling medium CF flows from the outer shroud <NUM> through the cooling holes formed in the stator blade <NUM> and the inner shroud <NUM> respectively in sequence. Thereby, the stator blade <NUM> and the like are cooled. Then, the cooling medium CF used for cooling the stator blade <NUM> is discharged to, for example, the main flow path through which the working medium F flows inside the inner casing <NUM>.

As described above, the throttle mechanism 50a is not installed at the third rotor cooling flow path part H213 intended for introducing the cooling medium into the turbine stage <NUM> on the upstream side Us from the final-stage turbine stage <NUM> out of a plurality of the third rotor cooling flow path parts H213. Similarly, the throttle mechanism 50a is not installed at the second inner casing cooling medium flow path part H312 intended for introducing the cooling medium into the turbine stage <NUM> on the upstream side Us from the final-stage turbine stage <NUM> out of a plurality of the second inner casing cooling medium flow path parts H312. However, the throttle mechanism 50a is installed at the third rotor cooling flow path part H213 and the second inner casing cooling medium flow path part H312 intended for introducing the cooling medium into the final-stage turbine stage <NUM>. Therefore, the cooling medium is introduced into the final-stage turbine stage <NUM> via the throttle mechanism 50a.

In the final-stage turbine stage <NUM>, the cooling medium CF that has flowed into the space located between the inner peripheral surface of the heat insulating plate <NUM> and the outer peripheral surface of the turbine rotor <NUM> is introduced into the rotor blade <NUM> and additionally flows to the final-stage wheel space RW located on the downstream side Ds from the final-stage rotor wheel <NUM> in the axial direction. The cooling medium CF that has flowed to the final-stage wheel space RW leaks from the inside to the outside of the turbine casing <NUM> in the downstream-side gland part G2. Specifically, in the downstream-side gland part G2, the cooling medium CF flows to the space between the inner peripheral surface of the packing head <NUM> where the gland sealing parts 35c are provided and the outer peripheral surface of the turbine rotor <NUM>.

<FIG> is a view illustrating the relationship between a temperature of the cooling medium CF (cooling temperature) and a time. <FIG> is a view illustrating the relationship between a flow rate of the cooling medium CF (cooling flow rate) and a time.

<FIG> and <FIG> each illustrate the above-described turbine <NUM> with respect to the period between the time when a startup operation starts and the time when a rated operation starts. <FIG> illustrates flow rates of the cooling medium CF supplied to the plural (four) turbine stages respectively, "STG1" indicates the case of the first-stage (initial-stage) turbine stage <NUM>, "STG2" indicates the case of the second-stage turbine stage <NUM>, "STG3" indicates the third-stage turbine stage <NUM>, and "STG4" indicates the fourth-stage (final-stage) turbine stage <NUM>. Further, in <FIG>, the case of the turbine <NUM> is illustrated by a "solid line," and unlike the turbine <NUM>, the case of the related art with no installation of the throttle mechanism 50a is illustrated by a "broken line.

As illustrated in <FIG>, the temperature of the cooling medium CF (cooling temperature) rises with the passage of time proportionally. In other words, the temperature of the cooling medium CF (cooling temperature) rises linearly during the period from the start of startup to the start of rated operation. In order to increase the cooling temperature, ignition of the combustor <NUM> (see <FIG>) is performed.

As illustrated by the broken lines in <FIG>, in the case of the related art with no installation of the throttle mechanism 50a, which is different from the turbine <NUM>, the flow rate of the cooling medium CF supplied to each of the plural (four) turbine stages <NUM> (cooling flow rate) increases with the passage of time because the pressure at a turbine inlet increases. The flow rate at which the cooling medium CF flows to each of the plural (four) turbine stages <NUM> at the beginning of startup (left side in <FIG>) decreases as the position of the turbine stage <NUM> shifts from the upstream side to the downstream side. The rate at which the flow rate of the cooling medium CF increases with time increases as the position of the turbine stage <NUM> shifts from the upstream side to the downstream side. A blade surface heat transfer coefficient is small at the beginning of startup (left side in <FIG>), and thus, the flow rate of the cooling medium CF (cooling flow rate) may be small. However, at the beginning of startup (left side in <FIG>), the flow rate of the cooling medium CF may be insufficient because of a small differential pressure between the working medium and the cooling medium CF in the turbine stage <NUM> of the fourth stage STG4 (final stage), as described above.

As illustrated by the solid lines in <FIG>, even in the case of this turbine <NUM>, the flow rate of the cooling medium CF supplied to each of the plural (four) turbine stages <NUM> at the start of rated operation (right side in <FIG>) (cooling flow rate) is the same as in the case of the related art.

In the turbine <NUM>, the throttle mechanisms 50a are installed. As described above, the throttle mechanism 50a is installed at the third rotor cooling flow path part H213 and the second inner casing cooling medium flow path part H312 intended for introducing the cooling medium into the turbine stage <NUM> of the fourth stage STG4 (final stage). The throttle mechanism 50a is configured to make the cross-sectional areas of the third rotor cooling flow path part H213 and the second inner casing cooling medium flow path part H312 (second cooling medium flow path part) small as temperature rises. As illustrated in <FIG>, the temperature of the cooling medium CF (cooling temperature) rises with the passage of time, and thus, the pressure loss increases with the passage of time in the throttle mechanism 50a. Therefore, the throttle mechanism 50a makes the cross-sectional area of the flow path through which the cooling medium CF flows larger at the beginning of startup (left side in <FIG>) than at the start of rated operation (right side in <FIG>).

As illustrated by the solid line in <FIG>, in the case of the turbine <NUM>, the flow rate of the cooling medium CF to be introduced into the turbine stage <NUM> of the fourth stage STG4 (final stage) at the beginning of startup (cooling flow rate) increases as compared to the related art. Therefore, the flow rate of the cooling medium CF to be introduced into the turbine stage <NUM> located on the upstream side (STG1 to STG3) from the fourth stage STG4 (final stage) at the beginning of startup decreases as compared to the related art.

As a result, the rate at which the flow rate of the cooling medium CF to be introduced into the turbine stage <NUM> of the fourth stage STG4 (final stage) increases according to time is lower than in the related art. In contrast to this, the rate at which the flow rate of the cooling medium CF to be introduced into another turbine stage <NUM> increases according to time is larger than in the related art.

As described above, the throttle mechanism 50a is not installed at the cooling medium flow path intended for introducing the cooling medium CF into the turbine stage <NUM> on the upstream side from the final stage, but at the cooling medium flow path intended for introducing the cooling medium CF into the final-stage turbine stage <NUM>, the throttle mechanism 50a is installed. The throttle mechanism 50a is configured to make the cross-sectional area of the cooling medium flow path small as temperature rises. Thereforeas described above, the cooling medium CF can be sufficiently introduced into the final-stage turbine stage <NUM> during the period from the beginning of startup to the start of rated operation. Further, it is possible to perform an autonomous adjustment with the temperature of fluid without external access or adjustment.

The throttle mechanism 50a is not installed at the third rotor cooling flow path part H213 (first cooling medium flow path part) intended for introducing the cooling medium into the turbine stage <NUM> on the upstream side Us side from the final-stage turbine stage <NUM> out of a plurality of the third rotor cooling flow path parts H213. Further, the throttle mechanism 50a is not installed at the second inner casing cooling medium flow path part H312 (first cooling medium flow path part) intended for introducing the cooling medium into the turbine stage <NUM> on the upstream side Us side from the final-stage turbine stage <NUM> out of a plurality of the second inner casing cooling medium flow path parts H312 constituting the inner casing cooling medium flow path H31. However, the present invention is not limited to this. The throttle mechanism 50a may be installed also at the cooling medium flow path with no installation of the throttle mechanism 50a as necessary.

Further, there has been explained the case where the third rotor cooling flow path part H213 has one end thereof, which is located on the inner side in the radial direction, communicating with the second rotor cooling flow path part H212 and has the other end thereof, which is located on the outer side in the radial direction, communicating with the space located between the inner peripheral surface of the heat insulating plate <NUM> and the outer peripheral surface of the turbine rotor <NUM>. However, the present invention is not limited to this. Of the third rotor cooling flow path part H213, the other end located on the outer side in the radial direction may directly communicate with a cooling flow path inside the rotor blade <NUM>.

Further, there has been explained the case where the throttle mechanisms 50a having the same configuration are installed at the third rotor cooling flow path part H213 and the second inner casing cooling medium flow path part H312 (second cooling medium flow path part). However, the present invention is not limited to this. As a matter of course, the throttle mechanisms 50a having different configurations may be installed at the third rotor cooling flow path part H213 and the second inner casing cooling medium flow path part H312 (second cooling medium flow path part) as necessary.

There is explained one example of a turbine <NUM> using <FIG>.

<FIG> schematically illustrates a partial cross section of the turbine <NUM> as in <FIG>.

In the turbine <NUM>, throttle mechanisms 50b are provided. The throttle mechanisms 50b are installed at positions different from those of the throttle mechanisms 50a in <FIG>. Except for this and related points, the turbine <NUM> is the same as in <FIG>. Therefore, the explanations of overlapping matters will be omitted as appropriate.

The throttle mechanism 50b is not installed at the third rotor cooling flow path part H213 (first cooling medium flow path) intended for introducing the cooling medium into the turbine stage <NUM> on the downstream side DS side from the initial-stage (first-stage) turbine stage <NUM> out of a plurality of the third rotor cooling flow path parts H213 constituting the rotor cooling flow path H21. The throttle mechanism 50b is installed at the third rotor cooling flow path part H213 (second cooling medium flow path) intended for introducing the cooling medium into the initial-stage turbine stage <NUM> out of a plurality of the third rotor cooling flow path parts H213.

Further, the throttle mechanism 50b is not installed at the second inner casing cooling medium flow path part H312 (first cooling medium flow path) intended for introducing the cooling medium into the turbine stage <NUM> on the downstream side Ds side from the initial-stage (first-stage) turbine stage <NUM> out of a plurality of the second inner casing cooling medium flow path parts H312 constituting the inner casing cooling medium flow path H31. The throttle mechanism 50b is installed at the second inner casing cooling medium flow path part H312 (second cooling medium flow path) intended for introducing the cooling medium into the initial-stage turbine stage <NUM> out of a plurality of the second inner casing cooling medium flow path parts H312.

The throttle mechanism 50b has the same configuration as that of the throttle mechanism <NUM> in the embodiment and is configured to make the cross-sectional areas of the third rotor cooling flow path part H213 and the second inner casing cooling medium flow path part H312 intended for introducing the cooling medium into the initial-stage (first-stage) turbine stage <NUM> large.

<FIG> is a view illustrating the relationship between a flow rate of the cooling medium CF (cooling flow rate) and a time in the turbine.

Similarly to <FIG>, <FIG> illustrates flow rates of the cooling medium CF supplied to the plural (four) turbine stages respectively, "STG1" indicates the case of the first-stage (initial-stage) turbine stage <NUM>, "STG2" indicates the case of the second-stage turbine stage <NUM>, "STG3" indicates the third-stage turbine stage <NUM>, and "STG4" indicates the fourth-stage (final-stage) turbine stage <NUM>. Further, in <FIG>, similarly to <FIG>, the case of the turbine <NUM> is illustrated by a "solid line," and unlike the turbine <NUM>, the case of the related art with no installation of the throttle mechanism 50b is illustrated by a "broken line.

As illustrated by the solid lines in <FIG>, even in the case of the turbine <NUM>, the flow rate of the cooling medium CF supplied to each of the plural (four) turbine stages <NUM> at the start of rated operation (cooling flow rate) (right side in <FIG>) is the same as in the case of the related art.

In the turbine <NUM>, the throttle mechanisms 50b are installed. As described above, the throttle mechanism 50b is installed at the third rotor cooling flow path part H213 and the second inner casing cooling medium flow path part H312 intended for introducing the cooling medium into the turbine stage <NUM> of the first stage STG4 (initial stage). The throttle mechanism 50b is configured to make the cross-sectional areas of the third rotor cooling flow path part H213 and the second inner casing cooling medium flow path part H312 (second cooling medium flow path part) large as temperature rises. As illustrated in <FIG>, the temperature of the cooling medium CF (cooling temperature) rises with the passage of time, and thus, the pressure loss in the throttle mechanism 50b decreases with the passage of time. Therefore, the throttle mechanism 50b makes the cross-sectional area of the flow path through which the cooling medium CF flows smaller at the beginning of startup (left side in <FIG>) than at the start of rated operation (right side in <FIG>).

As illustrated by the solid line in <FIG>, in the case of the turbine <NUM>, the flow rate of the cooling medium CF to be introduced into the turbine stage <NUM> of the first stage STG1 (initial stage) at the beginning of startup (cooling flow rate) decreases as compared to the related art. Therefore, the flow rate of the cooling medium CF to be introduced into the turbine stage <NUM> located on the downstream side (STG2 to STG4) from the first stage STG1 (initial stage) at the beginning of startup increases as compared to the related art.

As a result, the rate at which the flow rate of the cooling medium CF to be introduced into the turbine stage <NUM> of the first stage STG1 (initial stage) increases according to time is higher than in the related art. In contrast to this, the rate at which the flow rate of the cooling medium CF to be introduced into another turbine stage <NUM> increases according to time is smaller than in the related art.

As described above, the throttle mechanism 50b is not installed at the cooling medium flow path intended for introducing the cooling medium CF into the turbine stage <NUM> on the downstream side from the initial stage, but at the cooling medium flow path intended for introducing the cooling medium CF into the initial-stage turbine stage <NUM>, the throttle mechanism 50b is installed. The throttle mechanism 50b is configured to make the cross-sectional area of the cooling medium flow path large as temperature rises. Therefore, the cooling medium CF can be sufficiently introduced into the final-stage turbine stage <NUM> during the period from the beginning of startup to the start of rated operation. Further, it is possible to perform an autonomous adjustment with the temperature of fluid without external access or adjustment.

There is explained an example of a turbine <NUM> using <FIG>.

<FIG> schematically illustrates a partial cross section of the turbine <NUM> similarly to <FIG> and <FIG>.

In the turbine <NUM>, in addition to the throttle mechanism 50a, the throttle mechanism 50b is provided. Except for this and related points, this turbine <NUM> is the same as the turbine in <FIG> and the turbine in <FIG>. Therefore, the explanations of overlapping matters will be omitted as appropriate.

In this embodiment, the throttle mechanisms 50a are installed in the same manner as in <FIG>. Specifically, the throttle mechanism 50a is installed at the third rotor cooling flow path part H213 (second cooling medium flow path part) intended for introducing the cooling medium into the final-stage turbine stage <NUM> out of a plurality of the third rotor cooling flow path parts H213. Further, the throttle mechanism 50a is installed at the second inner casing cooling medium flow path part H312 (second cooling medium flow path part) intended for introducing the cooling medium into the final-stage turbine stage <NUM> out of a plurality of the second inner casing cooling medium flow path parts H312. The throttle mechanism 50a is configured to make the cross-sectional areas of the third rotor cooling flow path part H213 and the second inner casing cooling medium flow path part H312 (second cooling medium flow path part) intended for introducing the cooling medium into the final-stage turbine stage <NUM> small.

The throttle mechanisms 50b are installed in the same manner as in <FIG>. That is, the throttle mechanism 50b is installed at the third rotor cooling flow path part H213 (second cooling medium flow path part) intended for introducing the cooling medium into the initial-stage turbine stage <NUM> out of a plurality of the third rotor cooling flow path parts H213. Further, the throttle mechanism 50b is installed at the second inner casing cooling medium flow path part H312 (second cooling medium flow path part) intended for introducing the cooling medium into the initial-stage turbine stage <NUM> out of a plurality of the second inner casing cooling medium flow path parts H312. The throttle mechanism 50b is configured to make the cross-sectional areas of the third rotor cooling flow path part H213 and the second inner casing cooling medium flow path part H312 (second cooling medium flow path part) intended for introducing the cooling medium into the final-stage turbine stage <NUM> large.

Similarly to <FIG> and <FIG>, <FIG> illustrates flow rates of the cooling medium CF supplied to the plural (four) turbine stages respectively, "STG1" indicates the case of the first-stage (initial-stage) turbine stage <NUM>, "STG2" indicates the case of the second-stage turbine stage <NUM>, "STG3" indicates the third-stage turbine stage <NUM>, and "STG4" indicates the fourth-stage (final-stage) turbine stage <NUM>. Further, in <FIG>, similarly to <FIG> and <FIG>, the case of the turbine <NUM> is illustrated by a "solid line," and unlike the turbine <NUM>, the case of the related art with no installation of the throttle mechanism 50b is illustrated by a "broken line.

In the turbine <NUM>, the throttle mechanism 50a and the throttle mechanism 50b are installed. As described above, the throttle mechanism 50a makes the cross-sectional area of the flow path through which the cooling medium CF flows larger at the beginning of startup (left side in <FIG>) than at the start of rated operation (right side in <FIG>). In contrast to this, the throttle mechanism 50b makes the cross-sectional area of the flow path through which the cooling medium CF flows smaller at the beginning of startup (left side in <FIG>) than at the start of rated operation (right side in <FIG>).

The flow rate of the cooling medium CF to be introduced into the turbine stage <NUM> of the fourth stage STG4 (final stage) at the beginning of startup (cooling flow rate) increases as compared to the related art due to the function of the throttle mechanism 50a as in <FIG>.

Further, the flow rate of the cooling medium CF to be introduced into the turbine stage <NUM> of the first stage STG1 (initial stage) at the beginning of startup (cooling flow rate) decreases as compared to the related art due to the function of the throttle mechanism 50b as in <FIG>. Therefore, the flow rate of the cooling medium CF to be introduced into the turbine stage <NUM> located on the downstream side stage (STG2 to STG4) from the first stage STG1 (initial stage) at the beginning of startup increases as compared to the related art.

As a result, the flow rate of the cooling medium CF to be introduced into the turbine stage <NUM> of the fourth stage STG4 (final stage) at the beginning of startup (cooling flow rate) increases as compared to <FIG> and <FIG> due to the functions of the throttle mechanism 50a and the throttle mechanism 50b.

As described above, at the cooling medium flow path intended for introducing the cooling medium CF into the final-stage turbine stage <NUM>, the throttle mechanism 50a is installed, and at the cooling medium flow path intended for introducing the cooling medium CF into the initial-stage turbine stage <NUM>, the throttle mechanism 50b is installed. The throttle mechanism 50a is configured to make the cross-sectional area of the cooling medium flow path small as temperature rises. The throttle mechanism 50b is configured to make the cross-sectional area of the cooling medium flow path large as temperature rises. Therefore, as described above, the cooling medium CF can be sufficiently introduced into the final-stage turbine stage <NUM> during the period from the beginning of startup to the start of rated operation. Further, it is possible to perform an autonomous adjustment with the temperature of fluid without external access or adjustment.

While an embodiment has been described, this embodiment has been presented by way of example only, and is not intended to limit the scope of the invention as defined in claim <NUM>.

For example, in the above-described embodiment, there has been explained the case where the throttle mechanism <NUM> (50a, 50b) is installed in the turbine <NUM> being the CO2 turbine into which a supercritical working medium (working CO<NUM> medium) is introduced, but the present invention is not limited to this. The throttle mechanism <NUM> (50a, 50b) may be installed in the turbine <NUM> into which another medium is introduced as the working medium as necessary.

Claim 1:
A throttle mechanism (<NUM>) for controlling a flow rate of a cooling fluid flowing through a flow path of a turbine comprising:
a first flow path forming member (<NUM>) in which a first through hole (H61) forming the flow path and a trench (T61) communicating with the first through hole (H61) are formed;
a second flow path forming member (<NUM>) in which a second through hole (H62) forming the flow path is formed, the second flow path forming member (<NUM>) movably installed inside the trench (T61); and
a biasing member (<NUM>) biasing the second flow path forming member (<NUM>) in a moving direction of the second flow path forming member (<NUM>) inside the trench (T61), wherein the biasing member (<NUM>) includes:
a first biasing member (<NUM>) installed on one side in the moving direction inside the trench (T61); and
a second biasing member (<NUM>) installed on the other side in the moving direction inside the trench (T61),
a material that forms the first biasing member (<NUM>) and a material that forms the second biasing member (<NUM>) are different from each other in the tendency that a Young's modulus changes according to temperature, and
the throttle mechanism (<NUM>) is configured to make the cross-sectional area of the flow path change by an overlapping portion of the first through hole (H61) and the second through hole (H62) varying in size as the second biasing member (<NUM>) moves inside the trench (T61) according to temperature.