EP2585684B1 - Single-casing steam turbine with reheating - Google Patents

Description

Technical area

The present invention relates to a turbine system, in particular a steam turbine system, and a method for operating the turbine system.

Background of the invention

In steam power plants, steam is used to operate steam turbines as the working medium. The steam is heated in a steam boiler and flows via pipelines into the steam turbine. In the steam turbine, the previously absorbed energy of the working medium is converted into kinetic energy. By means of kinetic energy, a generator is operated, which converts the generated mechanical power into electrical power. Thereafter, the expanded and cooled steam flows into a condenser where it is condensed by heat transfer in a heat exchanger and returned as liquid water to the steam boiler for heating.

In order to increase the efficiency of a steam power plant, the steam is reheated after a first turbine stage in a reheater before the water vapor is fed back to a second turbine stage. In the superheater, the steam is heated further beyond its evaporation temperature and fed to the following second turbine stage. In multi-stage steam turbines, such a reheating of the water vapor is carried out between the individual turbine stages. This leads to a higher efficiency, since by means of the superheated steam more efficient mechanical energy can be generated in the turbine stages.

In the implementation of reheat systems in steam turbines, the material of the outer wall in particular highly stressed between the turbine stages. At the first turbine stage, the colder water vapor is removed, fed to the reheater, and the heated water vapor is fed to the second turbine stage. In this case, high temperature differences occur in the outer wall in the transition between the first turbine stage and the second turbine stage. Since the end of the first turbine stage, from which the colder steam is removed and the beginning of the second turbine stage, in which the hot steam is supplied from the reheater, are close to each other, high thermal stresses occur in the outer wall. This can lead to leaks or cracks in the outer wall. Furthermore, there is a risk that, when the cold steam is removed from the first turbine stage, wet steam parameters prevail and, as a result, condensate is applied to the inner wall of the outer housing. The condensate additionally cools the inside of the outer wall. Thus, the thermal stress on the outer wall is increased. The temperatures of the superheated steam are therefore cooled to reduce the thermal stresses, so that the superheated steam does not cause harmful thermal stresses. This is usually done in upstream Einströmgehäusen. However, these additional inflow housing can lead to energy losses.

From the JP 06 185303 For example, a turbine system including a friction preventing device for a steam turbine seal case (2) is known. The device has a rotor shaft (1), which is surrounded by sealing lamellae (3), which are mounted on a sealing ring (2a). The sealing ring (2a) is connected via support rings (2b) to the seal housing (2) radially inwardly. The sealing ring (2a) is coupled to a heating device (4) by means of which the sealing ring can be heated. If the temperature of an auxiliary steam flow which is provided by an auxiliary steam boiler is too low, the sealing ring (2a) is heated via the heating system (4) in order to avoid a contraction of the sealing ring. In this case, the heating takes place in the mass that at the same time a rubbing of the sealing plates (5) with the rotor shaft (1) is avoided. For this purpose, the seal housing (2) has a temperature sensor (5) in order to keep the temperature of the sealing ring constant.

Presentation of the invention

It is an object of the present invention to reduce thermal stresses in an outer wall of a turbine. This object is achieved by a turbine system, in particular a steam turbine system, and a method for operating the steam turbine system according to the independent claims.

According to a first aspect of the present invention, a turbine system, in particular a steam turbine system is provided. The turbine system has a turbine shaft, a first one Turbine area and a second turbine area. The second turbine region is arranged in the axial direction of the turbine shaft after the first turbine region. Furthermore, the turbine system has a housing with an outer wall, a first partition and a second partition. The outer wall has an extension along the first turbine region and the second turbine region in the axial direction. The outer wall extends, for example, along the first turbine region and the second turbine region substantially in the axial direction. The first divider wall and the second divider wall are each coupled to the outer wall and each have a radial extension toward the turbine shaft so that the first divider wall limits the expansion of the first turbine region in the axial direction and the second turbine wall limits the extension of the second turbine region in the axial direction , The first partition wall is spaced from the second partition wall along the axial direction such that a gap is defined, which is bounded at least by a part of the outer wall, the first partition wall and the second partition wall. The first dividing wall is set up such that a first working medium can be flowed into the intermediate space from the first turbine region with a first working pressure and wherein the second dividing wall is set up such that a second working medium with a second working pressure, which is lower than the first working pressure, for example can be flowed from the second turbine region in the intermediate space, so that a fluid mixture of the first working medium and the second working medium in the intermediate space can be generated, wherein a first mass flow (m1) of the first working medium (A1) due to the formation of the first partition wall (111 ) and a second mass flow (m2) of the second working medium (A2) are adjustable such that in the intermediate space (104) the fluid mixture (Fm) has a mean temperature range with respect to the first temperature (T1) of the first working medium (A1) in the first turbine section (101) and the second en temperature (T2) of the second working medium (A2) in the second turbine section (102), and wherein the first working medium (A1) and the second working medium (A2) to the fluid mixture (Fm) are mixed, thereby characterized depending on the proportionate volume a certain fluid temperature arises, which has the temperature range between the first temperature (T1) of the first working medium (A1) and the second temperature (T2) of the second working medium (A2).

In accordance with another aspect of the present invention, a method of operating the turbine system described above described. According to the method, the first working medium with the first working pressure from the first turbine region is flowed into the intermediate space. The second working medium is at the second working pressure, which is lower than the first working pressure, flowed from the second turbine region in the intermediate space, so that a fluid mixture of the first working medium and the second working medium in the gap, and adjusting the first mass flow (m1) of the first working medium (A1) due to the formation of the first partition wall (111) and the second mass flow (m2) of the second working medium (A2) the formation of the second partition wall (112) such that in the intermediate space (104) the fluid mixture (Fm) has a mean temperature range with respect to the first temperature (T1) of the first working medium (A1) in the first turbine region (101) and the second temperature (T2 ) of the second working medium (A2) in the second turbine region (102), wherein the first working medium (A1) and the second working medium (A2) are mixed to form the fluid mixture (Fm), thereby producing a specific fluid temperature depending on the proportionate volume, which the temperature range between the first temperature (T1) of the first working medium (A1) and the second temperature (T2) of the second working medium (A2) up eist.

In an exemplary embodiment of the invention, the first working pressure in the first turbine region has a higher working pressure than a second working pressure of the second working medium. The first turbine region can therefore form the high-pressure turbine and the second turbine region the low-pressure turbine of the turbine system.

For example, the term "turbine region" describes a turbine stage. A turbine section includes, for example, functional elements such as a stator or a moving space and / or a guide for a rotor or a turbine runner. In a turbine area, an energy portion of the working medium is converted into mechanical energy. Furthermore, a combustion chamber can be set up in a turbine area.

As a working medium, for example, steam or other fluids can be used in the gaseous state. Furthermore, as a working medium and any fluid in the vapor state can be understood with liquid and gaseous components. The first working medium is understood as the working medium which flows through the first turbine region and has a first working pressure and a first temperature in the first turbine region. The second working medium is understood as the working medium which flows through the second turbine region and has a second working pressure and a second temperature.

The outer wall of the housing is understood as the one boundary of the housing, which in particular the largest radial Distance from the turbine shaft has. Furthermore, the outer wall extends in the longitudinal direction substantially parallel to the turbine shaft. In this case, the outer wall extends along the first turbine region, the second turbine region and the Gap and forms part of the lateral surface of the housing.

The axial direction can be understood as the direction which runs along the turbine shaft from the first turbine region to the second turbine region. For example, the axial direction is defined as the direction along the turbine shaft along which the working fluid flows from a first high pressure turbine region to a second lower pressure turbine region than in the first turbine region.

The term "dividing wall" is understood to mean a wall which extends essentially radially or radially expands and which extends from the outer wall in the direction of the turbine shaft. A partition wall particularly defines a turbine area in the axial direction. In other words, a turbine region is defined in the axial direction by the region which is bounded by two partitions, which extend essentially radially. The first partition wall is in particular that partition wall which delimits the first turbine area in the direction of the adjacent second turbine area. The second partition wall is the partition wall of the second turbine section which is located closest to the first partition wall.

By a spacing of the first partition in the axial direction to the second partition, the gap is formed. The space is bounded by the first partition, the outer wall and the second partition. In the radial direction, the gap is limited for example by the turbine shaft or by other radially arranged elements. The intermediate space differs, for example, from the turbine areas in that a medium in the intermediate space does no work, so that no energy of the medium in the intermediate space is converted into mechanical energy. In particular, the intermediate space has no functional internals which are involved in the energy conversion (eg rotors, Stators), on. The gap may moreover also comprise functional devices which are not directly involved in the energy conversion.

The first working medium and the second working medium can flow into the intermediate space through devices in the first dividing wall and the second dividing wall. This creates the fluid mixture in the intermediate space. Depending on the inflowing mass per unit time (mass flow) of the first working medium and the second working medium in the intermediate space for the fluid mixture respectively mixing parameters, such as a certain fluid temperature and a certain fluid pressure, which is the result of mixing the respective first and second parameters of the first and second working medium are. The intermediate space is formed, in particular, in that the fluid mixture in the intermediate space is in thermal contact with the outer wall or with the area of the outer wall which forms the intermediate space. Thus, heating or cooling of the outer wall can be produced by the fluid mixture.

With the present invention, a gap is provided between the first turbine region and the second turbine region. As a result, the region of the outer wall that runs along the first turbine region no longer directly adjoins the region of the outer wall that runs along the second turbine region. With such a direct transition of the first turbine region to the second turbine region, high temperature jumps occur in the transition on the outer wall. Due to the different temperatures between the first working medium and the second working medium therefore large temperature jumps can occur in the transition region on the outer wall, which lead to high thermal stresses in the material of the outer wall.

With the generated gap according to the present invention, the first working medium and the second working medium is now mixed to form a fluid mixture, so that ever after proportional volume, a certain fluid temperature is formed, which in particular has a temperature range between the first temperature of the first working medium and the second temperature of the second working medium. As a result, an average temperature corresponding to the fluid temperature of the fluid mixture is set in the region of the intermediate space on the outer wall. As a result, the high temperature differences between the first working medium in the first turbine region and the second working medium in the second temperature region in the transition region between the first turbine region and the second turbine region are reduced on the outer wall. Thus, the material stress of the outer wall is reduced. In other words, due to the gap, the temperature transition along the outer wall is stretched from the first turbine region to the second turbine region, or a larger transition region is provided.

Due to the lower thermal stresses on the outer wall in the transition region in particular the material stress of the outer wall is reduced. Furthermore, the thermal expansions of the outer wall are more manageable, so that small gap dimensions must be planned on the outer wall. This leads in particular to the fact that the tightness of the housing is increased.

According to a further exemplary embodiment, the outer wall is integrally formed. In particular, according to the exemplary embodiment, the outer wall is integrally formed along the first turbine section, the intermediate space, and the second turbine section. Due to the reduction of the thermal stresses by forming a gap between the first turbine region and the second turbine region, an integrally formed outer wall is possible. The material of the outer wall is reduced due to the reduced thermal stresses along the first turbine region and the second turbine region by the intervening gap, so that, for example, no expansion gaps are necessary. This can be done in one and the same Manufacturing process, for example, in one and the same casting, the outer wall are poured, so that a cheaper and faster manufacturing process of the outer wall and thus the housing is made possible. Further, mounting steps that would be necessary to mount a plurality of different outer wall parts are eliminated.

According to a further exemplary embodiment, a first mass flow of the first working medium due to the formation of the first dividing wall and a second mass flow of the second working medium due to the formation of the second partition so adjustable that in the intermediate space, the fluid mixture, a mean temperature range with respect to the first temperature of the first working medium in the first turbine region and the second temperature of the second working medium in the second temperature range can be generated. The middle temperature range comprises a temperature of the fluid mixture which is between the temperature of the first working medium and the temperature of the second working medium. With this average fluid temperature in the intermediate space, the area of the outer wall in the intermediate space is correspondingly heated. Thus, a gentler temperature transition is created from the first temperature to the second temperature, so that thermal stresses of the outer wall are reduced.

Due to their design, the dividing walls can control the mass flows by the dividing walls having, for example, an opening with a predetermined opening diameter. In addition, control valves can be installed in each of these openings in order to variably control the first mass flow or the second mass flow.

Furthermore, the first mass flow or the second mass flow can be controlled by the formation of the respective partition wall in that a radial expansion of the respective partition wall from the outer wall in the direction of the turbine shaft is predetermined, so that forms a predefined opening gap between the turbine shaft and the respective partition , Accordingly, in a further exemplary embodiment of the invention, the first partition wall is formed such that a first gap between the first partition wall and the turbine shaft is formed, so that the first working medium of the first turbine portion in the intermediate space, in particular with a predetermined first mass flow, einströmbar is. Accordingly, in a further exemplary embodiment, the second partition wall may be formed such that a second gap is formed between the second partition wall and the turbine shaft, so that the second working medium can be flowed into the intermediate space with a predetermined second mass flow from the second turbine region.

According to a further exemplary embodiment, the turbine system comprises a sealing element disposed between the first partition wall and / or the second partition wall and the turbine shaft to control the inflow of the first mass flow or the second mass flow in the gap. The sealing element may in particular be arranged in the first gap and / or the second gap, so that a predetermined first mass flow or a predetermined second mass flow is adjustable. The sealing element may be arranged non-rotatably, for example, on the turbine shaft or on the respective partition wall. The sealing element may have a sealing ring or a labyrinth seal.

According to a further exemplary embodiment, the outer wall in the first turbine region has a first opening for the outflow of the first working medium from the housing. Due to the outflow of the first working medium from the first opening, a specific first working pressure in the first turbine region can be set. In addition, the effluent working fluid can be fed to a reheater. In the reheater, for example, at a substantially constant first working pressure, the first temperature of the first working medium is increased until the first temperature corresponds to the value of the second temperature. through reheat of the working fluid increases the efficiency of the turbine system.

In a further exemplary embodiment, the outer wall in the second turbine region has a second opening for the flow of the second working medium into the housing. For example, the superheated second working medium can flow through the second opening, so that the effectiveness of the turbine system is increased. The second opening is in particular configured such that the second working medium can be supplied from the reheater. In the reheater, for example, the first working medium is supplied, then superheated and discharged as the second working medium with the second temperature and the second working pressure. The second working medium has substantially the same pressure as the first working pressure, wherein the second working medium has a significantly higher second temperature as a result of the reheating compared to the first temperature of the first working medium.

According to a further exemplary embodiment, the outer wall in the region of the intermediate space has a third opening, from which the fluid mixture can flow out of the housing. By a controlled outflow of the fluid mixture from the intermediate space, for example, the fluid pressure in the intermediate space can be adjusted.

According to a further exemplary embodiment, the outflow of the fluid mixture by means of the third opening is controllable such that a fluid pressure of the fluid mixture in the intermediate space is less than the first working pressure of the first working medium in the first turbine region and less than the second working pressure of the second working medium in the second turbine region , By adjusting the fluid pressure of the fluid mixture in the intermediate space beyond the first mass flow of the first working medium and the second mass flow of the second working medium can be adjusted. The higher the pressure gradient between the fluid pressure and the first working pressure or the second working pressure, the higher the first mass flow or the second mass flow.

According to a further exemplary embodiment, the turbine system has a control valve which is coupled to the third opening for controlling the outflow of the fluid mixture. By means of the control valve, the fluid pressure is adjustable.

According to another exemplary embodiment, the turbine system further includes a pressure chamber coupled to control the outflow of the fluid mixture to the third port. Into the pressure chamber, the fluid mixture can be flowed in from the intermediate space. The pressure chamber is adapted to adjust the fluid pressure of the fluid mixture in the pressure chamber. Depending on the fluid pressure of the fluid mixture in the pressure chamber, a mass flow of the outflowing fluid mixture can also be set. Thus, for example, the pressure difference of the fluid pressure in the intermediate space on the one hand and the first working pressure and the second working pressure on the other hand be increased or reduced, which in turn is the first mass flow and the second mass flow adjustable.

According to a further exemplary embodiment, the outer wall extends in the axial direction along a third turbine region, wherein the third turbine region is arranged in the axial direction after the second turbine region. The outer wall in the third turbine region has a fourth opening which is coupled to the third opening in such a way that the fluid mixture can be flown in from the outside of the housing into the third turbine region through the fourth opening. With the exemplary embodiment, in particular the fluid mixture can be flowed into the third turbine region for further energy release. The fluid mixture, which serves for thermal compensation of the outer wall between the first and second turbine region, can thus be further processed efficiently become. Thus, a high efficiency is generated in the entire steam cycle of the turbine system.

The third turbine region can furthermore have a further intermediate space in the region of the inflow of the fluid mixture through the fourth opening, so that the inflowing fluid mixture tempers the region along the further gap of the outer wall. Thus, the same fluid mixture can reduce thermal stresses even in a transition region of the outer wall between the second turbine region and the third turbine region.

With the present invention, a separation of the mostly colder first working medium and the intermediate overheated hotter second working medium is created on the outer wall along the gap. From the intermediate space, the fluid mixture generated in the intermediate space is removed, for example by coupling a pressure chamber to the intermediate space, wherein the fluid mixture in the pressure chamber has a lower pressure than the fluid pressure in the intermediate space. In the space adjusts itself by the inflow of the first working medium and the second working medium, a mixing temperature, whereby the temperature gradient between the usually colder first working fluid and the usually hotter second working fluid is distributed over a larger axial extent. Thus, e.g. Tightness of joints in the boundary areas of the turbine areas are better adjusted. In addition, an integrally molded outer housing can be created so that joints can be unnecessary. Furthermore, an additional inflow housing for reducing the temperature of the superheated steam can be dispensed with. Thus, larger volumes or mass flows of the working medium are manageable, in particular, since the steam connections can be connected directly to the outer housing without passing through the additional inflow housing.

It should be noted that the embodiments described herein are only a limited selection of possible Represent variants of the invention. Thus, it is possible to suitably combine the features of individual embodiments with one another, so that for the person skilled in the art with the variants of embodiment that are explicit here, a multiplicity of different embodiments are to be regarded as obviously disclosed.

Short description of the drawing

In the following, for further explanation and for a better understanding of the present invention, embodiments will be described in detail with reference to the accompanying figure.

The figure shows an exemplary embodiment of the turbine system according to an embodiment of the present invention.

Detailed description of exemplary embodiments

The same or similar components are provided in the figure with the same reference numerals. The illustration in the figure is schematic and not to scale.

The figure shows a turbine system 100, in particular a steam turbine system, according to an exemplary embodiment of the present invention. The turbine system 100 has a turbine shaft 105, a first turbine region 101 and a second turbine region 102. The second turbine region 101 is arranged in the axial direction 106 of the turbine shaft 105 after the first turbine region 101.

Furthermore, the turbine system 100 has a housing 110 with an outer wall 113, a first partition 111 and a second partition 112. The outer wall 113 has an extension along the turbine shaft 105. In particular, the outer wall 113 extends along the first turbine portion 101 and the second turbine portion 102 in the axial direction 106. The first Partition wall 111 and second partition wall 112 are respectively coupled to outer wall 113 and each have a radial extension toward turbine shaft 105 such that first partition wall 111 limits expansion of first turbine section 101 in axial direction 106 and second partition wall 112 limits expansion of the second turbine section bounded in the axial direction.

The first partition wall 111 is spaced from the second partition wall 112 along the axial direction 106 such that a gap 104 is formed, which is bounded at least by a part of the outer wall 113 of the first partition wall 111 and the second partition wall 112. The first partition wall 111 is set up such that a first working medium A1 can be flowed into the intermediate space 104 with a first working pressure P1 from the first turbine region 101. Furthermore, the second dividing wall 112 is set up in such a way that a second working medium A 2 having a second working pressure P 2, which is lower than the first working pressure P 1 for example, can be flowed into the intermediate space 104 from the second turbine region 102, so that a fluid mixture Fm of the first working medium A1 and the second working medium A2 in the intermediate space 104 can be generated.

The first partition wall 111 and / or the second partition wall 112 can be produced, for example, in one piece together with the outer wall 113, in particular by means of a casting method. In addition, the first partition wall 111 and / or the second partition wall 112 can be manufactured separately or independently of the outer wall 113 and subsequently connected to the outer wall 113, for example by means of a screw connection or by electron beam welding.

In the first turbine region 101, for example, there is a turbine device 130, such as a rotor or a stator, via which the first working medium A1 emits energy and converts it into mechanical energy. The first working medium A1 can through the first partition 111 flow through. For example, the first partition wall 111 has a flow-through opening, or, as shown in the figure, a first gap 114. The first gap 114 is defined, for example, by the distance of the radial end of the first turbine wall 111 to the turbine shaft 105. In this first gap 114, a sealing element 116, such as a labyrinth seal, may be arranged. By dimensioning the gap 114 and / or the dimensioning of the sealing element 116, a first mass flow m1 of the first working medium A1 in the intermediate space 104 can be controlled.

Accordingly, the second working medium A2 is located in the second turbine region 102. Between the second dividing wall 112 and the turbine shaft 105, a second gap 115 is provided, through which the second working medium A2 flows into the intermediate space 104. The second mass flow M2 of the second working medium A2 can be adjusted via the dimensioning of the second gap 115 and / or via a sealing element 116 arranged in the second gap 115.

In the intermediate space 104, the first working medium A1 and the second working medium A2 mix to form a fluid mixture Fm. The fluid pressure Pm of the fluid mixture Fm depends on the one hand on the size of the first mass flow m1 and the second mass flow m2. The first mass flow m1 and the second mass flow m2 in turn depend on the size of the passage in the first partition wall 111 and the second partition wall 112 and in addition on the first working pressure P1 and the second working pressure P2. In addition, the pressure Pm of the fluid mixture Fm depends on how much fluid mixture Fm flows out of the intermediate space 104, for example via a third opening 119.

Due to the supplied first and second mass flows m1, m2 and due to the first temperature T1 of the first working medium A1 and the second temperature T2 of the second working medium A2, a predetermined fluid temperature Tm is set in the gap 104. The fluid mixture Fm transfers thermal energy to the region of the outer wall 113, which extends in the longitudinal direction (axial direction 106) along the gap 104.

For example, in the first turbine region 101, a first working pressure of approximately 40-50 bar and a first temperature of approximately 300-400 ° C. prevail. In the second turbine region 102, the superheated second working medium A2 can flow in via a second opening 118. In the second turbine region 102, due to the parameters of the second working medium A2, for example, a working pressure P2 of approximately 35-45 bar and a second temperature T2 of approximately 500-600 ° C. prevail. Accordingly, the outer wall 113 is heated in the region of the first turbine region 101 with the first temperature T1 and the outer wall 113 along the second turbine region 102 with the second temperature T2. As a result of the inflow of the first working medium A1 and the inflow of the second working medium A2 into the intermediate space 104, a fluid temperature Tm of approximately 400-500 ° C. is established by controlling the first mass flow m1 and the second mass flow m2. In particular, the fluid temperature Tm is selected such that approximately the average temperature between the first temperature T1 and the second temperature T2 in the intermediate space 104 is set. Further, a fluid pressure Pm of the fluid mixture Fm in the clearance 104, which is smaller than the first working pressure P1 and the second working pressure P2, that is, is set. about 30 to 40 bar. The outer wall 113 in the region of the intermediate space 104 is heated with the fluid temperature Tm of the fluid mixture Fm. Thus, the outer wall 113 along the gap 104, the corresponding average temperature, since the outer wall 113 along the gap 104 is tempered by the fluid mixture. The introduction of the intermediate space 104 thus reduces the thermal stress in the outer wall 113 in the axial direction 106, since smaller temperature jumps occur.

The figure shows that in the first turbine region 101, the first opening 117 is arranged, through which the first working medium A1 can flow out and, for example, a heater 109 (eg reheater) can be fed.

In the heating device 109, the first working pressure P1 is kept substantially constant, while the first working medium A1 is heated to the second temperature T2. From the heating device 109, the second working medium A2 flows out, which now has the second temperature T2, which is generally higher than the first temperature T1.

Subsequently, the second working medium A2 is supplied through the second opening 118 to the second turbine section 102. The second working pressure P2 of the second working medium A2 is due to line losses usually slightly lower than the first working pressure P1 of the first working medium A1.

In the second turbine region 102, energy of the second working medium A2, for example via the turbine device 130, is converted into mechanical energy.

Via the third opening 119, the fluid mixture Fm flows out. For controlling the outflow of the fluid mixture Fm, a control valve 107 may be coupled to the third opening 119. Via the control valve 107, the outflow is controlled selectively, so that a predetermined fluid pressure Pm prevails in the intermediate space 104. This takes place in particular by the fact that a targeted flow of the fluid mixture Fm from the intermediate space 104, an inflow of the first working medium A1 with the first mass flow M1 and an inflow of the second working medium A2 with the second mass flow M2 is controllable. The more fluid mixture Fm flows out through the third opening 119, the lower the fluid pressure Pm, whereby the more of the first working medium A1 and the second working medium A2 flows into the intermediate space 104.

Alternatively or in addition to the control valve 107, a pressure chamber 108 may be coupled to the third opening 119. In the pressure chamber 108, the fluid mixture Fm is cached and further processed. Furthermore, a targeted outflow of the fluid mixture Fm through the third opening 119 can also be adjusted by means of the pressure chamber 108.

The fluid mixture Fm can either be supplied to the environment or be flowed through a conduit through a fourth opening 120 into a third turbine region 103. In this third turbine region 103, the fluid mixture Fm serves as the third working medium A3, which has a third working pressure P3 and a third temperature T3. In the third turbine region 103, energy can be extracted from the third working medium A3 via turbine device 130 and converted into mechanical energy.

Instead of flowing directly into a third turbine region 103, the fluid mixture Fm can also be supplied to a further intermediate space, which is formed, for example, between the second turbine region 102 and the third turbine region 103. Thus, thermal stresses on the outer wall 113 can also be reduced by means of the further intermediate space.

In addition, it should be noted that "inclusive" does not exclude other elements or steps, and "a" or "an" does not exclude a multitude. It should also be appreciated that features or steps described with reference to one of the above embodiments may also be used in combination with other features or steps of other embodiments described above. Reference signs in the claims are not to be considered as limiting.

Claims (13)

1. Turbine system (100) having
   a turbine shaft (105),
   a first turbine region (101),
   a second turbine region (102), which is arranged after the first turbine region (101) in the axial direction (106) of the turbine shaft (105), and
   a casing (110) with an outer wall (113), a first partition (111) and a second partition (112),
   wherein the outer wall (113) extends along the first turbine region (101) and the second turbine region (102),
   wherein the first partition (111) and the second partition (112) are each coupled to the outer wall (113) and each extend radially towards the turbine shaft (105) such that the first partition (111) bounds the extent of the first turbine region (101) in the axial direction (106) and the second partition (112) bounds the extent of the second turbine region (102) in the axial direction (106),
   wherein the first partition (111) is spaced apart from the second partition (112) in the axial direction (106) so as to form an interspace (104) which is bounded at least by part of the outer wall (113), the first partition (111) and the second partition (112),
   wherein the first partition (111) is set up such that a first working medium (A1) at a first working pressure (P1) can be made to flow from the first turbine region (101) into the interspace (104) and wherein the second partition (112) is set up such that a second working medium (A2) at a second working pressure (P2) can be made to flow from the second turbine region (102) into the interspace (104) so as to be able to generate a fluid mixture (Fm) of the first working medium (A1) and the second working medium (A2) in the interspace (104),
   wherein a first mass flow (m1) of the first working medium (A1) can be set on the basis of the design of the first partition (111) and a second mass flow (m2) of the second working medium (A2) can be set on the basis of the design of the second partition (112) such that, in the interspace (104), the fluid mixture (Fm) has an average temperature range with respect to the first temperature (T1) of the first working medium (A1) in the first turbine region (101) and the second temperature (T2) of the second working medium (A2) in the second turbine region (102), and
   wherein the first working medium (A1) and the second working medium (A2) are mixed to give the fluid mixture (Fm) such that, thereby, depending on the volume fraction, there results a certain fluid temperature in the temperature range between the first temperature (T1) of the first working medium (A1) and the second temperature (T2) of the second working medium (A2).
2. Turbine system (100) according to Claim 1,
   wherein the outer wall (113) is formed in one piece.
3. Turbine system (100) according to Claim 1 or 2,
   wherein the first partition (111) is designed such that a first gap (114) is formed between the first partition (111) and the turbine shaft (105), such that the first working medium (A1) can be made to flow from the first turbine region (101) into the interspace (104).
4. Turbine system (100) according to one of Claims 1 to 3,
   wherein the second partition (112) is designed such that a second gap (115) is formed between the second partition (112) and the turbine shaft (105), such that the second working medium (A2) can be made to flow from the second turbine region (102) into the interspace (104).
5. Turbine system (100) according to one of Claims 1 to 4, further having,
   a sealing element (116) which is arranged between the first partition (111) - or the second partition (112) - and the turbine shaft (105) in order to control the inflow of the first mass flow (m1) or of the second mass flow (m2) into the interspace (104).
6. Turbine system (100) according to one of Claims 1 to 5,
   wherein the outer wall (113) in the first turbine region (101) has a first opening (117) for the first working medium (A1) to flow out of the casing (110).
7. Turbine system (100) according to one of Claims 1 to 6,
   wherein the outer wall (113) in the second turbine region (102) has a second opening (118) for the second working medium (A2) to flow into the casing (110).
8. Turbine system (100) according to one of Claims 1 to 7,
   wherein the outer wall (113) in the region of the interspace (104) has a third opening (119) out of which the fluid mixture (Fm) can be made to flow out of the casing (110).
9. Turbine system (100) according to Claim 8,
   wherein the outflow of the fluid mixture (Fm) can be controlled by means of the third opening (119) such that a fluid pressure (Pm) of the fluid mixture (Fm) in the interspace (104) is smaller than the first working pressure of the first working medium (A1) in the first turbine region (101) and smaller than the second working pressure (P2) of the second working medium (A2) in the second turbine region (102).
10. Turbine system (100) according to Claim 8 or 9, further having
    a control valve (107) which is coupled to the third opening (119) for the purpose of controlling the outflow of the fluid mixture (Fm).
11. Turbine system (100) according to one of Claims 8 to 10, further having
    a pressure chamber (108) which is coupled to the third opening (119) for the purpose of controlling the outflow of the fluid mixture (Fm),
    wherein the fluid mixture (Fm) can be made to flow from the interspace (104) into the pressure chamber (108), and
    wherein the pressure chamber (108) is set up to set the fluid pressure (Pm) of the fluid mixture (Fm) in the pressure chamber (108).
12. Turbine system (100) according to one of Claims 8 to 11,
    wherein the outer wall (113) runs in the axial direction (106) along a third turbine region (103), wherein the third turbine region is arranged after the second turbine region (102) in the axial direction (106), and
    wherein the outer wall (113) in the third turbine region (103) has a fourth opening (120) which is coupled to the third opening (119) such that the fluid mixture (Fm) can be made to flow from outside the casing (110) into the third turbine region (103) via the fourth opening (120).
13. Method for operating a turbine system (100) according to one of Claims 1 to 12, the method comprising
    making the first working medium (A1) at the first working pressure (P1) flow from the first turbine region (101) into the interspace (104),
    making the second working medium (A2) at the second working pressure (P2) flow from the second turbine region (102) into the interspace (104) so as to generate a fluid mixture (Fm) of the first working medium (A1) and the second working medium (A2) in the interspace (104), and
    setting the first mass flow (m1) of the first working medium (A1) on the basis of the design of the first partition (111) and setting the second mass flow (m2) of the second working medium (A2) on the basis of the design of the second partition (112) such that, in the interspace (104), the fluid mixture (Fm) has an average temperature range with respect to the first temperature (T1) of the first working medium (A1) in the first turbine region (101) and the second temperature (T2) of the second working medium (A2) in the second turbine region (102), wherein the first working medium (A1) and the second working medium (A2) are mixed to give the fluid mixture (Fm) such that, thereby, depending on the volume fraction, there results a certain fluid temperature in the temperature range between the first temperature (T1) of the first working medium (A1) and the second temperature (T2) of the second working medium (A2).

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