JP2007211676A - Steam turbine and solar heat rankine system using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the efficiency of a steam turbine and to reduce it in size by preventing the enlargement of the disk diameter of the steam turbine and increasing a viscous force and adherence by the steam. <P>SOLUTION: This steam turbine is provided with: rotors 3 having wavelike radial cross section and rotating by steam 2 jetted out from a nozzle 1; a rotor unit 11 fixed onto a rotary shaft 4 with clearances formed between respective rotors 3 when superposing the plurality of rotors 3; an exhaust port 9 of the steam 2 provided around the rotary shaft 4 of the rotors 3; and a casing 13 constituting the nozzle 1 and the rotor unit 11 for exhausting the steam 2 from the exhaust port 9 via the clearance 7. The steam 2 jetted out form the nozzle 1 moves along the surface of the rotors whose surface area is expanded and stagnates there for a long period of time to improve the viscous force and the adherence and raise a torque applied to the rotary shaft 4 of the rotors 3. This constitution improves the efficiency of the steam turbine 16 and prevents the enlargement of the diameter of the steam turbine 16 to make the steam turbine compact. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a steam turbine of a Rankine system using solar heat.

Conventionally, in this type of steam turbine, steam flows from the outer periphery toward the shaft through a flat disk, which is densely attached to the output shaft at narrow intervals, and the disk is rotated by the viscous force and adhesion force of the steam. (For example, refer to Patent Document 1). There is also a Tesla turbine that uses only a viscosity using a flat disk.
JP 2002-174166 A

    However, in the prior art, a simple shape is formed by stacking a large number of planar disks, but by increasing the surface area of the disk in order to take advantage of the viscosity and adhesion of steam, There was a problem that the diameter increased.

  The present invention solves the above-mentioned conventional problems, and since the surface area can be increased without increasing the diameter of the rotor, the steam viscosity and adhesion are increased to improve the efficiency of the steam turbine, The purpose is to make it compact.

  In order to solve the above-described conventional problems, the present invention provides a nozzle for ejecting steam, a rotor having a wavy radial cross section rotated by the ejection of steam from the nozzle, and a plurality of the rotors. A rotor unit fixed on a rotating shaft through a gap between the rotors, a steam outlet provided around the rotating shaft of the rotor, and the steam passes through the gap between the rotors and is discharged from the outlet. Thus, the steam turbine is provided with a nozzle and a casing for housing the rotor unit.

  With this steam turbine, the steam ejected from the nozzle moves along the rotor and stays on the surface of the rotor with a large area for a long time, thereby utilizing the viscous force and adhesive force to rotate the rotor and output the rotating shaft. Since it can raise, the efficiency of a steam turbine can be improved, the expansion of the diameter of a steam turbine can be prevented, and compactness can be achieved.

  In the steam turbine of the present invention, the steam ejected from the nozzle stays on the rotor surface for a long time, and the torque applied to the rotor rotation shaft can be increased by improving the viscosity and adhesion of the steam. It is possible to reduce the size of the steam turbine by preventing the diameter of the steam turbine from expanding.

According to a first aspect of the present invention, a nozzle for ejecting steam, a radial cross section is wavy, a rotor rotating by ejecting steam from the nozzle, and a plurality of the rotors are overlapped with a gap between the rotors. And a rotor unit fixed on the rotating shaft, a steam discharge port provided around the rotating shaft of the rotor, and a nozzle and a rotor unit so that the steam passes through the gap and is discharged from the discharge port. By providing the casing, the steam ejected from the nozzle moves along the rotor and stays on the rotor surface with a large area for a long time, and uses the viscous force and adhesive force to rotate the rotor and increase the output of the rotating shaft Therefore, the efficiency of the steam turbine can be improved, and the diameter of the steam turbine can be prevented from being enlarged, thereby achieving a compact size.

    In the second invention, in particular, the crest and valley of the wave-like cross section of the rotor of the steam turbine in the first invention are made concentric with the rotation axis as the center, thereby facilitating the rotor molded into the same shape. The assembly accuracy of the rotor unit can be improved by forming a uniform gap.

  In the third aspect of the invention, in particular, the peaks and valleys of the wavy cross section of the rotor of the steam turbine in the first invention are spiraled toward the center of the rotation axis, so that the peaks and valleys of the wavy cross section are obtained. The steam flowing through the part can be guided in a spiral, and the residence time of the steam flowing through the rotor can be lengthened, and the torque applied to the rotating shaft can be increased by rotating the rotor using the viscous force and adhesion force Therefore, the efficiency of the steam turbine can be improved.

  In the fourth aspect of the invention, in particular, when a plurality of the rotors of the steam turbine according to any one of the first to third aspects are mounted on the rotating shaft, a spacer is provided between the rotors to control the size of the gap. As a result, the flow rate of the steam passing through the gaps between the rotors can be made uniform, an even force can be transmitted to the rotating shaft, and a stable rotational torque can be obtained.

  In the fifth aspect of the invention, in particular, by providing an impulse element for obtaining an impulse in the gap between the rotors of the steam turbine in any one of the first to fourth inventions, the steam moving along the rotor can be obtained. Since the impinging force is generated by colliding with the impulsive element and rotating the rotor, the kinetic energy of the steam can be efficiently transmitted to the rotating shaft, the shaft output of the steam turbine can be increased, and the efficiency of the steam turbine can be improved.

  In the sixth aspect of the invention, in particular, the fifth impulse element is also configured to serve as a spacer for managing the size of the rotor gap, whereby the size of the rotor gap can be managed without increasing the number of parts. It is possible to reduce the number of man-hours and materials required for assembly, thereby reducing the cost and reducing the rotor unit.

  In the seventh aspect of the invention, in particular, in the rotor unit of the steam turbine according to any one of the first to sixth aspects, a fixed rotor having a thickness greater than that of each rotor is disposed at the end of the rotor in which a plurality of rotors are stacked. As a result, it is possible to obtain a stable torque by increasing the rigidity of the rotor unit, preventing deflection during rotation, and stabilizing the rotation.

  In the eighth aspect of the invention, in particular, the steam turbine according to any one of the first to seventh aspects can be mounted on a solar thermal Rankine system to realize a power generation, hot water supply / heating cogeneration system.

(Embodiment 1)
FIG. 1 is a configuration diagram of a steam turbine according to a first embodiment of the present invention. Fig.1 (a) is a longitudinal cross-sectional view of a steam turbine, (b) is XX ｀ cross-sectional view of (a). FIG. 2 is a configuration diagram of the steam turbine and the solar thermal Rankine system in the first embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes a nozzle that ejects steam 2, and a plurality of rotors 3 that rotate by receiving the kinetic energy of the steam 2 ejected from the nozzle 1 are provided around a rotating shaft (output shaft) 4. ing. The steam 2 is high-temperature chlorofluorocarbon or water steam, and may be a gas body such as air. It may also be a supercritical fluid such as high temperature and pressure CO2. The rotor 3 has a shape having a peak portion 5 (shown by a broken line) and a recessed valley portion 6 (shown by an alternate long and short dash line) that are raised with respect to the reference plane when viewed from one side in the axial direction. It is said. By setting it as such a shape, the surface area is expanded, without enlarging the diameter of the rotor 3. FIG. The peak portion 5 and the valley portion 6 are formed concentrically around the rotation axis 4. A gap 7 is formed which has the same width when a plurality of the rotors 3 are stacked in the center of the rotor 3 so as to pass through the rotation shaft 4. Spacers 8 are provided between the rotors 3 to form the gaps 7. The spacer 8 extends to the vicinity of the outer periphery of the rotor 3 and is in close contact with the gap 7 between the rotor 3 and the rotor 3 so that there is no gap, and the impulsive force that causes the steam 2 from the nozzle 1 to collide and rotate the rotor 3 is provided. It is also an impulsive element for creating. The rotor 3, the rotating shaft 4 and the spacer 8 are made of a heat-resistant and corrosion-resistant material. For example, the material is made of a metal material such as stainless steel, titanium or alumina, ceramic or glass. The rotor 3 has a thin thickness (for example, 1 mm or less) in order to reduce weight. Further, the gap 7 constituted by the rotor 3 and the rotor 3 is narrow (for example, 1 mm or less) so that the viscous force and the adhesion force of the steam 2 moving along the surface of the rotor 3 work. In the vicinity of the rotating shaft 4 of the rotor 3, a plurality of steam discharge ports 9 are provided. The steam 2 moves in the gap 7 while turning along the rotor surface 6 from the outer periphery of the rotor 3, converges in the vicinity of the rotation shaft 4, and escapes from the rotor 3 to the outside of the rotor 3. The spacer 8 constitutes a guide for the steam 2 so that the steam 2 can efficiently escape from the discharge port 9. A plurality of fixing rotors 10 that are thicker than the respective rotors 3 are provided at both ends of the rotor 3 and the spacer 8 that are overlapped. When the fixing rotor 10 and the rotating shaft 4 are fixed, the rotor 3 and the spacers are fixed. The rotor unit 11 is configured by tightening 8 to increase the rigidity of the rotor unit 11 and prevent the rotor unit 11 from being bent. When the rotor unit 11 is configured, a plurality of discharge ports 9 provided in each rotor 3 are provided so as to communicate coaxially. A plurality of discharge ports 12 communicating with the discharge ports 9 are provided on one side of the fixing rotor 10. The other of the fixing rotors 10 is not provided with a discharge port 12 so as to prevent the steam 2 from flowing out.

  The nozzle 1 is provided so that the steam 2 is ejected substantially perpendicularly to the rotating shaft 4 and collides with the outer peripheral portion of the rotor 3 from the tangential direction. The nozzle 1 has a single hole (can be round or slit) to eject the steam 2 toward the entire outer periphery of the rotor 3 or a plurality of nozzles 1 to eject the steam 2 into each of the gaps 5 between the rotors 3. Is provided. From the nozzle 1, the vapor | steam 2 is ejected at sound speed. As the shape of the nozzle 1, a single-hole nozzle, a tapered nozzle, a divergent nozzle, or the like used in an ordinary steam turbine is used. The nozzle 1 is also configured to have a diffuser portion so that the inner diameter is gradually increased from the throat portion toward the downstream in order to accelerate the flow velocity of the steam 2 from the sonic velocity to the supersonic velocity.

  A casing 13 is provided so as to prevent the steam 2 from leaking outside while covering the periphery of the nozzle 1, the rotating shaft 4 and the rotor unit 11. The gap 14 between the rotor unit 11 and the casing 13 is managed at such an interval that the steam 2 does not flow due to a short circuit. In the casing 13, bearings 15 for supporting the rotation of the rotating shaft 4 are provided at both ends of the rotating shaft 4. The bearing 15 uses a seal bearing or a non-contact fluid bearing. The components stored in the casing 13 constitute a steam turbine 16. The material of the casing 13 is composed of a heat-resistant and corrosion-resistant material like the rotor 3, and the material is composed of a metal material such as stainless steel, titanium, alumina, or ceramic, for example. Further, an annular discharge passage 18 through which the steam 2 discharged from the discharge port 9 of the rotor 3 and the discharge port 12 of the fixing rotor 10 flows is provided in one of the rotor units 11 of the casing 13. A discharge pipe 19 is provided in a part of the discharge passage 18 to take out the steam 2 after rotating the steam turbine 16 and send it again to the means for heating the steam 2.

A generator 17 that generates electric power by receiving the rotation of the rotating shaft 4 is provided outside the bearing 15 for the rotating shaft 4 of the steam turbine 16. For example, an outer rotor type three-phase AC generator is used as the generator, and this AC output is subjected to current control by an inverter (not shown) after full-wave rectification so as to obtain a stable current. Yes.

  In FIG. 2, reference numeral 20 denotes a heat collector that receives and collects solar heat, and in order to transmit the heat of the heat collector 20 to the heat storage tank 21, a first heat medium circuit 23 (closed) provided with a circulation pump 22 in the middle. Circuit). The heat collector 20 includes a tubular heat collector, a vacuum glass tube heat collector, a heat pipe heat collector, or the like. The first heat medium 24 circulating in the first heat medium circuit 23 is made of a liquid such as chlorofluorocarbon or water. (The first heat medium 24 may use CO2 or liquid air in a supercritical state.) The first heat medium 24 is heated by the heat collector 20 to become steam and sent to the heat storage tank 21, where heat exchange is performed. To condense and become liquid. The first heat medium 24 is sent again to the heat collector 20 by the circulation pump 22. By repeating this operation, heat is stored in the heat storage tank 21. The heat storage tank 21 is 100 ° C. or higher by using a latent heat type using a phase change of a molten salt having a high melting point, a sensible heat type using a molten salt, oil, or the like, or a steam accumulator for storing steam in the form of pressure water. To store the high temperature heat. Reference numeral 25 denotes a supply pump for supplying the steam 2 of the second heat medium 26 formed by using the heat of the heat storage tank 21 to the nozzle 1 of the steam turbine 16. The second heat medium 26 discharged from the steam turbine 16 is again supplied. It is provided in the middle of the second heat medium circuit 27 (closed circuit) sent to the heat storage tank 21. The second heat medium 26 circulating in the second heat medium circuit 27 is composed of a liquid such as chlorofluorocarbon or water and its vapor. (The second heat medium 26 may use CO2 or liquid air in a supercritical state.) A hot water storage tank 28 is provided in the middle of the steam turbine 16 and the supply pump 25 of the second heat medium circuit 27 to provide a steam turbine. Hot water is stored in the hot water storage tank 28 using the heat of the high-temperature steam 2 after giving kinetic energy to 16. The second heat medium 26 condenses into a liquid when transferring heat to the hot water storage tank 28, and is sent again to the heat storage tank 21 to be heated to form the vapor 2. By repeating this operation, hot water is stored in the hot water storage tank 28 while generating power by the generator 17 provided in the steam turbine 16. Hot water stored in the hot water storage tank 28 is supplied by the water supply pump 29 for hot water supply or heating.

  About the solar thermal Rankine system by the steam turbine comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.

    First, in order to form the steam 2 to be supplied to the nozzle 1 of the steam turbine 16, the circulation pump 22 is operated, the first heat medium 24 is circulated in the first heat medium circuit 23, and the solar heat is received. It heats with the heat collector 20, forms high temperature vapor | steam (or what mixed liquid, vapor | steam, and liquid etc.), and sends to the thermal storage tank 21. FIG. The heat storage tank 21 receives this steam and accumulates an amount of heat of about 200 ° C. The vapor of the first heat medium 24 condenses in the heat storage tank 21 to become a liquid, and is sent again to the heat collector 20 by the circulation pump 22 to be heated. This operation is repeated while solar heat can be supplied, so that the necessary amount of heat is maintained in the heat storage tank 21.

When a predetermined amount of heat is accumulated in the heat storage tank 21, the second heat medium 26 is circulated by the supply pump 25 provided in the second heat medium circuit 27, and the steam of the second heat medium 26 at about 200 ° C. in the heat storage tank 21. 2 is ejected from the nozzle 1 of the steam turbine 20. The steam 2 ejected from the nozzle 1 has kinetic energy at the speed of sound and rotates inside the gap 7 formed between the rotors 3 along the rotor surface 6 while colliding with the surface of the rotor 3 of the steam turbine 16. The gas is discharged from a discharge port 9 provided around the rotary shaft 4. At this time, the rotor unit 11 is rotated by the viscosity force or adhesion force of the steam 2 and is transmitted as torque of the rotating shaft 4. At the same time, the steam 2 moving along the surface of the rotor 3 collides with the spacer 8 as an impulse element, and further generates an impulse for rotating the rotor 3. The generator 17 is rotated using the torque of the rotating shaft 4 to generate power. The steam 2 of the second heat medium 26 discharged from the steam turbine 16 is sent to the hot water storage tank 28 to exchange heat with water, and the heat is stored in the hot water storage tank 28 as hot water. The steam 2 condenses in the hot water storage tank 28, becomes a liquid, is sent to the heat storage tank 21 by the supply pump 25, and is heated again to form the steam 2.
By repeating this operation, hot water is stored in the hot water storage tank 28 while generating electricity with the steam turbine 16, and when the hot water supply or heating is necessary, the water supply pump 29 is operated to use the hot water so as to constitute a cogeneration system. I have to.

  As described above, in the present embodiment, the nozzle 1 that ejects the steam 2 of the second heat medium 26, the rotor 3 that is rotated by the steam 2 that is ejected from the nozzle 1, and the radial cross section of the rotor are wavy. Therefore, the surface area of the rotor 3 can be increased without increasing the diameter of the rotor 3. The steam 2 ejected from the nozzle 1 moves along the rotor surface 6 and stays on the rotor surface 6 having a large surface area for a long time, and the torque applied to the rotating shaft 4 is increased by rotating the rotor 3 using the viscous force and the adhesive force. In addition, the efficiency of the steam turbine 16 can be improved, and the diameter of the rotor 3 can be prevented from expanding, and the steam turbine 16 can be made compact. Further, the steam 2 ejected from the nozzle 1 stays on the rotor surface 6 for a long time, increases the viscous force and the adhesion force, and increases the torque applied to the rotating shaft 4, so that the power generation amount of the generator 17 can be increased. .

  Further, the peak portion 5 and the valley portion 6 of the rotor 3 are formed concentrically around the rotating shaft 4. Since each of the plurality of rotors 3 has the same shape and is symmetrical with respect to the axis, it is not necessary to precisely align the positions of the rotors 3 when they are stacked and assembled, and they are easily stacked. Can be assembled.

  In addition, since the spacer 8 is provided between the rotors 3 to control the size of the gaps, the flow rate of the steam passing through the gaps between the rotors is made uniform, and an even force is transmitted to the rotating shaft, so that a stable rotational torque can be obtained. Obtainable.

  Further, since the steam 2 moving along the surface of the rotor 3 collides with the spacer 8 as an impulse element and further generates an impulse for rotating the rotor 3, the kinetic energy of the steam 2 is efficiently transmitted to the rotating shaft 4, The torque of the steam turbine 16 can be increased, and the efficiency of the steam turbine 16 can be improved.

  The spacer 8 as the impulse element has a plurality of blade shapes so as to divide the surface of the rotor 3 like a blade of a turbofan, but is configured in a scroll shape that is continuous with one blade on the surface of the rotor. It is also possible to do.

  Note that the shape of the impulse element 30 in the vicinity of the rotating shaft 4 is configured so that the steam 2 can easily escape from the discharge port 9, but the structure may also generate reaction force and increase the torque of the steam turbine 16. Is possible.

  Moreover, since the independent 1st heat-medium circuit 23 for heat collection is comprised and the solar heat obtained with the heat collector 20 can always be stored and maintained in the thermal storage tank 21 irrespective of operation | movement of the steam turbine 16, power generation When necessary, the steam 2 required by the steam turbine 16 can be taken out at any time.

  Further, since the hot water storage tank 28 is provided in the middle of the second heat medium circuit 27, it is possible to store the heat of the heat storage tank 21 as hot water in the hot water storage tank 28 regardless of power generation. It can be taken out.

  Further, when the maximum power generation amount is increased, it is possible to increase the number of rotors 3 to be overlapped, and since there is no addition of a complicated shape, an increase in cost can be suppressed.

Further, the steam 2 ejected from the nozzle 1 stays on the rotor surface 6 for a long time, and increases the viscous force and adhesion force to increase the torque applied to the rotating shaft 4, so that the steam operating at a low temperature (about 200 ° C.). The turbine 16 can be realized. Moreover, since electric power is generated using solar heat, it can be an effective means for reducing CO2 emissions.
(Embodiment 2)
FIG. 3 is a configuration diagram of a steam turbine according to the second embodiment of the present invention. Fig.3 (a) is a longitudinal cross-sectional view of a steam turbine, (b) is XX ｀ cross-sectional view of (a). FIG. 4 is a configuration diagram of the steam turbine and the solar thermal Rankine system in the first embodiment of the present invention.

  The basic structure is the same as that of the first embodiment, and different points will be mainly described. In FIG. 3, the rotor 3 has a shape having a peak portion 5 (shown by a broken line) and a recessed valley portion 6 (shown by a one-dot chain line) that are raised with respect to the reference plane when viewed from one side in the axial direction. The cross section is wavy. By setting it as such a shape, the surface area is expanded, without enlarging the diameter of the rotor 3. FIG. The peak portion 5 and the valley portion 6 are formed in a spiral shape toward the center direction of the rotating shaft 4, and are two spirals of the peak portion 5 and the valley portion 6. A spacer 8 is brought into contact with a flat portion near the center of the rotor 3, and the rotor 3 is overlapped with a constant gap 7. In the rotor unit 11 configured by stacking a plurality of rotors 3 and spacers 8, a fixed rotor 10 having a thickness greater than that of each rotor is disposed at an end portion of the rotor 3 stacked in a plurality. The rotor unit 11 is fixed by tightening the rotor 3 and the spacer 8 when the fixing rotor 10 and the rotating shaft 4 are fixed to constitute the rotor unit 11. Since the crests 5 and troughs 6 of the rotor 3 are spiral, they need to be stacked in the same direction rather than in an axially symmetric shape. Therefore, when the plurality of rotors 3 and the spacers 8 constituting the gaps 7 are overlapped, The position where the plurality of discharge ports 9 provided in each rotor 3 communicate with the guide position of the steam 2 by the spacer 8 is aligned, the fixed rotor 10 is disposed at both ends, and the rotating shaft 4 is screwed and tightened. ing.

  In FIG. 4, the heat medium circuit 32 is formed so as to directly supply the steam 2 from the heat medium 31 heated in the heat collector 20 to the steam turbine 16. About the solar thermal Rankine system by the steam turbine comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.

  The heat medium 31 heated in the heat collector 20 becomes steam 2 and is directly supplied to the nozzle 1 in the steam turbine 16. The vapor 2 accelerated to the sonic speed in the nozzle 1 flows along the peaks and valleys of the wavy cross section along the spiral, and is discharged from the discharge port 9 provided around the rotating shaft 4. At this time, the rotor unit 11 is rotated by the viscosity force or adhesion force of the steam 2 and is transmitted as torque of the rotating shaft 4. The residence time of the steam flowing through the rotor becomes longer, and the torque applied to the rotating shaft can be increased by using the viscous force and the adhesion force to rotate the rotor, so that the efficiency of the steam turbine can be improved.

  As described above, in the present embodiment, the peaks and valleys of the wave-like cross section of the rotor 3 are spiraled toward the central direction of the rotating shaft 4 so that the peaks and valleys of the wave-like cross section are obtained. It is possible to increase the torque applied to the rotating shaft by rotating the rotor by using the viscous force and the adhesive force by increasing the residence time of the steam flowing through the rotor 3. As a result, the efficiency of the steam turbine can be improved.

Further, when the plurality of rotors 3 and the spacers 8 constituting the gaps 7 are overlapped, the position where the plurality of discharge ports 9 provided in the respective rotors 3 communicate with the guide position of the steam 2 by the spacers 8 is matched. 10 is arranged at both ends, and the rotary shaft 4 is screwed and tightened to form the rotor unit 11 with the gaps 14 equally spaced by overlapping the non-axisymmetric rotor 3 in the same direction. . In order to prevent displacement of the rotor 3 or the spacer 8 during rotation, a protrusion or groove is formed on the rotating shaft 4, and the protrusion or groove is formed and tightened on the insertion portion of the rotating shaft 4 of the rotor 3 or spacer 8. Is also possible.

  It should be noted that the present invention is not limited to the above-described embodiment, and in particular, the shape of details, the operating conditions of the apparatus, the material of each component, etc. are merely examples, and various modifications can be made without departing from the scope of the present invention. These variations or modifications are possible.

  As described above, since the steam turbine according to the present invention can operate the steam turbine by using heat with low energy density such as solar heat, it can be applied to exhaust heat recovery of automobiles and fuel cells to obtain electric power. Or get the axis output.

The block diagram of the steam turbine in the 1st Embodiment of this invention The block diagram of the steam turbine and solar Rankine system in a 1st embodiment of the present invention The block diagram of the steam turbine in the 2nd Embodiment of this invention The block diagram of the other steam turbine and solar thermal Rankine system in the 2nd Embodiment of this invention

Explanation of symbols

1 Nozzle 2 Steam 3 Rotor 4 Rotating shaft 7 Gap 8 Spacer (Impulse element)
9 Discharge port 10 Rotor for fixing 11 Rotor unit 13 Casing 16 Steam turbine

Claims (8)

A nozzle for jetting steam, a rotor having a wave-shaped cross section rotating by jetting steam from the nozzle, and a rotor fixed on a rotating shaft via a gap between the rotors when a plurality of the rotors are overlapped A unit, a steam discharge port provided around the rotation shaft of the rotor, and a casing that houses the nozzle and the rotor unit so that the steam passes through a gap between the rotors and is discharged from the discharge port. Steam turbine. The steam turbine according to claim 1, wherein the peaks and valleys of the wavy cross section of the rotor are concentric with the rotation axis as a center. The steam turbine according to claim 1, wherein the peaks and valleys of the wavy cross section of the rotor are spiraled toward the center of the rotation axis. The steam turbine according to any one of claims 1 to 3, wherein a spacer is provided between the rotors to control the size of the gap when the plurality of rotors are attached to the rotating shaft. The steam turbine according to any one of claims 1 to 4, further comprising an impulse element for obtaining an impulse between the rotors. The steam turbine according to claim 5, wherein the steam turbine is configured to also serve as a spacer for managing a dimension of a gap by an impulse element between the rotors. The steam turbine according to any one of claims 1 to 6, wherein a fixed rotor having a thickness greater than that of each rotor is disposed at an end of the rotor in which a plurality of rotors are overlapped. A solar thermal Rankine system configured to perform a power generation and hot water supply / heating cogeneration system using the steam turbine according to claim 1.

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