Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
  • F01D1/00—Non-positive-displacement machines or engines, e.g. steam turbines
  • F01D1/02—Non-positive-displacement machines or engines, e.g. steam turbines with stationary working-fluid guiding means and bladed or like rotor, e.g. multi-bladed impulse steam turbines
  • F01D1/04—Non-positive-displacement machines or engines, e.g. steam turbines with stationary working-fluid guiding means and bladed or like rotor, e.g. multi-bladed impulse steam turbines traversed by the working-fluid substantially axially
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
  • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
  • F05D2210/00—Working fluids
  • F05D2210/40—Flow geometry or direction
  • F05D2210/43—Radial inlet and axial outlet
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
  • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
  • F05D2220/00—Application
  • F05D2220/30—Application in turbines
  • F05D2220/31—Application in turbines in steam turbines

Definitions

• the present invention relates to the field of turbines for gas and steam expansion, in particular for expansion of a working fluid in an organic Rankine cycle (ORC), and specifically relates to improvements to the overall structure of a radial or axial or mixed type turbine, having one or more stages.
• ORC organic Rankine cycle
• the expansion gas and steam turbines essentially comprise a fixed body or housing having an inlet passage and an outlet passage for a working fluid, at least a first stator and any subsequent stators respectively of a first and any subsequent stages of the turbine, a shaft of the turbine rotating around an axis and carrying at least a first rotor and any subsequent rotors associated respectively to the first stator and to any subsequent stators.
• the expression tangential direction in a point of a meridian plane identifies the direction, orthogonal to the meridian plane and orthogonal to a radial direction passing through the point.
• a direction parallel to the rotation axis of the machine is defined axial direction.
• an axial stage of a turbine includes a row of stator blades and a corresponding array of rotor blades, respectively upstream and downstream relative to the direction of mass flow; in turn the flow predominantly occurs due to the axial component of the velocity within the flow.
• a radial turbine stage includes an array of stator blades and a corresponding array of rotor blades, respectively upstream and downstream, with respect to the direction of mass flow; in turn the flow predominantly occurs due to the radial component of the velocity within the flow.
• Figures 1 and 2 show a configuration example of a known type, in which are visible an inlet conduit 1 and an outlet duct 2 of a turbine 100 for ORC systems, the turbine being able to be radial, axial or mixed type. It is also visible an electric generator 3 mechanically connected to the turbine 100 directly or by interposition of a speed reducer.
• the radial outlet ducts 2 can also be of non-circular shape, for example rectangular.
• One of the characteristics of the use of an organic fluid as the working fluid for a Rankine cycle is that a high volumetric flow rates for entering and exiting the turbine it often required, so as to require large ducts especially in the turbine outlet.
• Subject of the present invention is therefore a turbine having at least one inlet duct for the working fluid feeding whose end portion is oriented along the axial direction and at least one outlet duct for the working fluid delivery, whose initial portion is oriented along the axial direction, as specified in the attached independent claim.
• FIG. 1 shows a side view of a turbine having an inlet with an axial duct and an outlet with a radial duct, according to the prior art
• FIG. 2 shows a front view of the turbine of Fig.l
• FIG. 3 shows a partial cross section of a turbine having two radial inlets, with an axial plenum and an outlet with axial duct, according to the present invention
• - Figure 4 shows a cross section of an axial turbine with inlet and outlet ducts configuration as in Figure 3 and also illustrates the path of the fluid inside the machine, which comprises at least one axial stage
• - Figure 5 shows a cross section of a radial turbine with inlet and outlet ducts configuration as in Figure 3 and also illustrates the path of the fluid inside the machine, which comprises at least one radial outflow stage;
• FIG. 6 shows a partial cross section of a turbine having an axial inlet and an axial outlet, according to a first design solution
• FIG. 7 shows a partial cross section of a turbine having a second design solution of the inlet and outlet ducts with respect to the turbine of Figure 6;
• FIG. 8 shows a partial cross section of a turbine having a third design solution of the inlet and outlet ducts with respect to the turbine of Figure 6;
• FIG. 9 shows a partial cross section of a turbine having a fourth design solution of the input and outlet ducts with respect to the turbine of Figure 6;
• FIG. 10 shows a partial cross section of a turbine having a fifth design solution of the input and outlet ducts with respect to the turbine of Figure 6;
• FIG. 11 shows a partial cross section of a turbine having a sixth design solution of the input and outlet ducts with respect to the turbine of Figure 6;
• FIG. 12 shows a partial cross section of a turbine with radial double inlet having a seventh design solution of the inlet and outlet ducts with respect to the turbine of Figure 6.
• the following description relates to a turbine 100 in which the mass transport from inlet to outlet of the fluid dynamic path where the expansion occurs is mainly due to the axial component of the fluid speed, and is referred to as axial turbine, or predominantly due to the radial component of the speed and is referred to as a radial turbine, or still as a mixed type turbine. All these types of turbines can be configured so as to have an end portion 10 "of the inlet duct 10 and an initial portion 20' of the outlet duct 20 in which the flow of the working fluid is oriented along the axial direction ( Figures 3 -12).
• FIG. 3 shows a generic turbine 100 having inlet ducts 10 in which a portion 10' is radially disposed and said portions converge in a central plenum 14.
• the outlet duct 20 and in particular its initial portion 20' is axially arranged, from the same side of the central plenum 14 with respect to the turbine 100 and has a substantially annular section, defined by an outer side wall 201 and an inner side wall 202.
• the high pressure central plenum 14 must be separated from the annular duct 20.
• This central plenum 14 of the turbine inlet can be separated by means of a flanged cover 9.
• the cover 9 (as shown in Figure 4) can have an elongated portion with function of flow distributor, possibly bladed, to confer the desired value of the tangential component to the stator inlet.
• the walls 201 and 202 can be designed to become the diffuser upstream of the exit from the turbine.
• the turbine 100 of Figure 4 is of the axial type, i.e. it comprises a housing 21, at least one stator group 22 comprising an array of stator blades 23, at least a rotor group 24, comprising a corresponding array of rotor blades 25, upstream and downstream, respectively, with respect to the direction of the working fluid, and a turbine shaft 26 that supports the rotor group.
• the flow is mainly due to the axial component of the velocity within the flow.
• the inversion 180 ° of the flow is achieved by means of shaping 13 internal to the housing 21 of the turbine 100.
• the turbine 100 of Figure 5 is of the radial centrifugal type and also comprises a housing 21, at least one stator group 22 comprising an array of stator blades 23, at least a rotor group 24, comprising a corresponding array of rotor blades 25, upstream and downstream, respectively, with respect to the direction of working fluid, and a turbine shaft 26 that supports the rotor group.
• the flow is mainly due to the radial component of the speed within the flow.
• the inversion 180 " of the flow is achieved by means of a deflector cone 15 upstream of the stator group 22 and shaping 13 downstream of the internal rotor 24 inside the housing of the turbine 100.
• the turbine 100 is shown in an alternative configuration still having an inlet duct 10 and an outlet duct 20, in the axial direction.
• the inlet duct 10 comprises a first portion 10' with a radial direction and a second end portion 10 " having an axial direction and in fluid connection with an inlet opening 101 of the turbine 100.
• the steam enters the turbine from the inlet duct 10 and exits through an annular outlet duct 20, in fluid connection with an outlet opening 102 of the turbine 100, which allows a wide outlet section.
• the annular conduit will preferably be configured so as to obtain a gradual reduction of the speed and then carry out a diffusion effect.
• the inlet duct 10 has a rigid structure due to a plurality of fixed constraints, for example weldings 5, present on the two side walls 201,202 of the annular duct 20.
• Figures 7 and 8 show two configurations having a lower structural rigidity.
• the inlet duct 10 is not constrained in a fixed manner to the annular duct 20 but is only fixed with its end portion 10 " to the inlet opening 101 of the turbine 100.
• the configuration of Figure 7 has a central chamber 8, bounded by the inner wall 202 of the outlet duct 20, at atmospheric pressure and in contact with the external environment.
• the chamber 8 is connected to the external environment by means of the hole 16 resulting from the presence of a radial duct 203 welded to the walls 201 and 202 of the outlet duct, and is sealed from the annular duct 20 by means of a seal 12, for example, a seal between the inner wall 202 of the annular duct 20 and the flanged cover 9 (figure 7).
• a seal 12 for example, a seal between the inner wall 202 of the annular duct 20 and the flanged cover 9 (figure 7).
• the configuration shown in Figure 8, show the duct 10 having an outer bellows 11 portion, to allow for thermal expansion, and a central chamber 8.
• Said central chamber 8 is in communication with the outlet opening 102 of the turbine and then has a pressure equal to the outlet of the turbine.
• the element 9 is not present not being necessary to isolate the central chamber 8 from the outlet opening 102.
• FIGS. 9 to 12 are shown configurations in which a flanged cover 9 is not required, because the central chamber 8 may be at the same pressure of the fluid leaving the turbine 100: in fact there is a clearance between the portion 10' of the inlet duct 10 and the hole 16 drilled in the duct 20 at the level of the inner wall 202. In this way, if there were a loss at the connection between the inlet duct 10 in its end portion 10 " and the inlet of the turbine 100, the loss would remain within the closed loop of the turbogenerator and should not be dispersed outside.
• the connection between the duct 10 and the outer wall of the annular duct 20 is of fixed type, made for example by means of welding.
• a further configuration presents the inlet duct 10 with a "T'shape, in which the radial portion 10' is the inlet flow and the axial portion 10" is the outlet flow.
• the presence of the bellows 11 and of tie rods 204 makes the "T" joint balanced according to the prior art, that is, a balanced thrusts compensator.
• the connection flange 205 to the turbine 100 has a certain freedom of movement with respect to the inlet duct 10' to which is bound and does not transmit the forces due to the pressure caused by the presence of two bellows 11 according to the prior art.
• a final configuration shown in Fig.12 has the inlet duct 10 realized by means of two radial portions 10' ( a double inlet is often required in the presence of larger volume flows at the turbine inlet) and a "T" element, that connects the two radial portions.
• the element 10 is the terminal portion of the duct 10 and is axially arranged. Even this element "T” is balanced with respect to the thrust of the internal pressure due to the presence of bellows 11, according to known techniques.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Turbine Rotor Nozzle Sealing (AREA)

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• 2016
  • 2016-03-01 EP EP16713990.6A patent/EP3265653B1/de active Active
  • 2016-03-01 WO PCT/IB2016/051121 patent/WO2016139574A1/en active Application Filing

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