Turbomachine with improved inlet guide vane

Abstract

A turbine for compressing a fluid, in particular air, is disclosed. The turbine includes an intake duct and an impeller for pressurizing a fluid, both housed within a housing body. The air inlet duct is equipped with an inlet for air entry and a flow path duct that directs incoming air towards the impeller. The intake duct incorporates a stator element defining a flow path and an adjustable inlet guide vane.

Description

Technical Field

[0001] This disclosure relates to the field of turbines. Specifically, this disclosure relates to variable inlet guide vanes for turbines (e.g., centrifugal compressors). Background Technology

[0002] In modern industry, turbines are fundamental components implemented in a wide range of applications. These mechanical devices, including turbines, compressors, and pumps, are capable of transferring energy between a rotor and a fluid, each playing a different role in fields ranging from power generation and aerospace to water resource management and treatment plants.

[0003] The ever-growing demand for energy efficiency and optimization has driven innovation in turbomachinery design and operation.

[0004] A turbine typically includes a flow path for a fluid, which includes an inlet, one or more impellers arranged for rotation within a casing, and an outlet. In a compressor (such as a centrifugal compressor), mechanical power is used to rotate the impellers and compress the fluid, while in an expander, the compressed fluid expands and drives the impellers to rotate to generate mechanical power.

[0005] Some turbines (such as centrifugal compressors) include variable inlet guide vanes (also known as IGVs) arranged at the inlet of the first (i.e., upstream) impeller. When the turbine's operating conditions change, such as when the rotational speed increases or decreases relative to the design operating point, the geometry of the inlet guide vanes can be controlled and changed to maximize the turbine's efficiency.

[0006] Furthermore, the demand for specialized compressors in industrial supercritical carbon dioxide (sCO2) applications is growing, particularly for IGC (Integrated Gear Compressor) type compressors. These centrifuges are distinguished by their high power density and are tuned to operate over a wide range on their characteristic curves, covering surge to choke conditions. IGV systems are typically integrated on the impeller's suction side, designed to skillfully regulate the inflow rate. However, conventional IGV designs have limitations. Reduced blade density and convergence of the flow path tend to accelerate fluid flow behind the IGV blades. This rapid acceleration subsequently leads to reduced flow directionality, thus compromising the desired efficiency.

[0007] An actuation system is provided to act simultaneously on each inlet guide vane and change its inclination as needed. The variable inlet guide vanes and associated actuation system are complex mechanical components that need to be assembled within the turbine casing, typically between the inlet filling chamber and the inlet side of the first impeller. However, in some cases, while the desired performance is improved, it is not entirely satisfactory.

[0008] It would be beneficial to improve the IGV system and related actuation systems to enhance their performance and improve impeller operation. Summary of the Invention

[0009] In one aspect, the subject matter disclosed herein relates to a turbine for compressing gases, such as air. The turbine may include: an impeller rotatable about an axial direction for pressurizing a gas flow path and housed within a housing; and an inlet assembly in airflow communication with the impeller. The inlet assembly includes: an inlet through which the gas to be pressurized can enter; and a flow path conduit configured to direct fluid entering through the inlet of the inlet conduit toward the impeller. The inlet assembly may include: a stator element defining a flow path conduit through which the gas flow can pass; and one or more inlet guide vanes. Each inlet guide vane includes a rod rotatably coupled to the stator element and movable blades fixed to the rod. The inlet assembly also includes one or more fixed blades, each corresponding to a corresponding guide vane arrangement. The inlet guide vanes and the fixed blades are arranged to adjust the angle of incidence of the fluid flow path before it enters the impeller.

[0010] On the other hand, this document discloses a head flange that includes a stator element and defines a circular inlet for airflow entry, wherein the head flange is fixed to the receiving body. Furthermore, the stem portion of each inlet guide vane is radially arranged in the stator element, and the inlet assembly may also include an electric actuator operatively coupled to a fixed portion to rotate the fixed portion about a rotation axis radially relative to the axial direction.

[0011] Another aspect of this disclosure relates to a rod portion that may include each inlet guide vane. The associated movable vane may pivot or rotate about the associated rod portion. The rod portion may engage an electric actuator, which may be an electric ring engaged with the rod portion. The actuator may be operated by engaging a lever connected to the rod portion.

[0012] On the other hand, the subject matter disclosed herein relates to a turbine in which each fixed blade may be arranged corresponding to a corresponding guide vane. Furthermore, the inlet assembly may include a apex arranged axially into a flow path duct. Each fixed blade may have a first end fixed to the apex and a second end fixed to the inner surface of the flow path duct. Each fixed blade may have a section adapted to intercept the flow path and direct it to a corresponding movable blade.

[0013] Another aspect of this disclosure relates to a turbine in which the inlet assembly includes a guiding element that is not only systematically positioned along the axial direction but also designed to significantly reduce turbulence caused by fluid deviation via movable blades of the inlet guide vanes. The guiding element, having an end connected to a apex and an opposite end oriented at the impeller inlet, continuously guides the flow path, thus demonstrating a strategic method for maintaining optimal, stable, and streamlined fluid flow within the turbine.

[0014] On the other hand, the subject matter disclosed herein relates to a guide element comprising a main portion and a terminal portion, the main portion having a cylindrical shape and the terminal portion having a larger cross-section than the main portion but also designed to correspond to the impeller inlet.

[0015] On the other hand, this paper discloses a turbine in which the spire and the guiding element are composed of individual pieces, forming a whole to manage and guide fluid flow.

[0016] On the other hand, the subject matter disclosed herein relates to an inlet assembly for regulating airflow through a turbine. The inlet assembly includes a stator element that defines a flow path duct, a path through which airflow can pass; the inlet assembly is further characterized by one or more inlet guide vanes. Each of these inlet guide vanes consists of a fixed portion and a movable blade rotatably coupled to the fixed portion, thereby regulating the angle of incidence of the fluid flow path before it enters the impeller. Attached Figure Description

[0017] When considered in conjunction with the accompanying drawings, the embodiments disclosed in this invention and their many accompanying advantages will become better understood by referring to the following detailed description, thereby readily providing a more comprehensive understanding of them, wherein:

[0018] Figure 1 A side view of a portion of a turbine according to a first embodiment is shown;

[0019] Figure 2 Examples Figure 1 A cross-sectional view of the turbine;

[0020] Figure 3 Examples Figure 1 A perspective view of a cross-section of a turbine;

[0021] Figure 4 Examples Figure 1 A front view of the turbine's air intake duct;

[0022] Figure 5 A schematic diagram illustrating the control of an electric actuator is shown.

[0023] Figure 6An example perspective view of a portion of a turbine according to a second embodiment is shown; and

[0024] Figure 7 yes Figure 6 A front view of the turbine's air intake duct. Detailed Implementation

[0025] This disclosure describes an axially oscillating inlet guide vane (IGV). The IGV resembles a series of blades designed to help guide the flow of fluid; in the case of air discussed herein. Conventional designs feature a single solid blade, but this innovation employs a unique approach. The blade is divided into two sections: the front section, closest to the inlet flow, remains stationary, while the rear section is movable. This separation not only enhances the blade but also provides finer control over the direction and rate of fluid flow.

[0026] This split-blade design offers several advantages, such as enhancing the overall structure of the blades, thereby allowing for more precise control over the incoming air.

[0027] Now for reference Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 The turbine 1 is shown in several views. The turbine 1 is primarily designed for compressing fluids, such as air. The turbine 1 provides greater efficiency and improved control over the fluid flow path as it transitions through the various sections of the turbine.

[0028] The turbine 1 includes a housing body 2. The housing body 2 serves as a protective shell for the internal components of the turbine 1 and is used to absorb and disperse mechanical vibrations of the moving parts during operation.

[0029] Within the housing 2, an impeller 3 and an inlet assembly 4 are arranged. The impeller 3 is capable of rotating about an axial direction A. When the impeller 3 rotates, it pressurizes the fluid entering it, thereby accelerating the fluid and increasing its pressure. The design considerations for the impeller 3 can vary based on the desired application, with some alternatives including radial, axial, and mixed-flow designs.

[0030] The turbine 1 also includes an inlet assembly 4, which, as mentioned, is located within the body 2. The inlet assembly 4 guides and compresses the fluid before it enters the impeller 3.

[0031] Inlet assembly 4 has an inlet 41 that allows fluid (such as air) to be drawn into turbine 1. Following inlet 41, the airflow is guided by flow path conduit 42. Flow path conduit 42 serves as a guide path, directing the fluid in a controlled manner toward impeller 3, as better explained below.

[0032] The inlet assembly 4 also includes a stator element 43 that defines a flow path conduit 42. The stator element 43 is a stationary component. It helps define the flow path conduit 42 and stabilizes the flow of fluid as it approaches the impeller 3. One or more inlet guide vanes 44 are integrated into the stator element 43. Each inlet guide vane 44 is movable and includes a rod 441 and movable blades 442. The rod 441 is coupled to the stator element 43. The inlet guide vane 44 is rotatably coupled to the stator element 43 and its position is adjustable. This movement allows the inlet guide vane 44 to deviate from or adjust the direction of the fluid flow path before it enters the impeller 3, thus allowing the machine operator better control over the angle of incidence of the fluid on the impeller 3. Tests have shown that changing the angle of incidence according to a specific algorithm or formula improves the compression efficiency of the impeller 3.

[0033] The movable blades 442 of the inlet guide vane 44 are housed in the flow path conduit 42 and converge toward the center (i.e. toward the axial direction A).

[0034] For some turbines, the inlet assembly 4 may include a head flange 45 fixed to the receiving body 2. The head flange 45 surrounds the stator element 43 and defines a circular inlet 451 for fluid entry.

[0035] In some embodiments, the rod portion 441 of each inlet guide vane 44 is radially oriented within the stator element 43. To enhance control over the inlet guide vanes 44, the inlet assembly 4 includes an electric actuator 49 (see [link to original document]). Figure 5 ).

[0036] The electric actuator is designed to move the movable blade 442 of the inlet guide vane 44 and is connected to and controlled by a control logic unit U, which may be part of the control system of the turbine 1 or integrated into the control system of the turbine 1.

[0037] Specifically, the control logic unit U can be implemented in various digital platforms, such as microprocessors or FPGA (Field Programmable Gate Array) devices. As is known, the function of the control logic unit U is to execute instructions to implement the passed algorithm and generate control signals to drive the electric actuator 49.

[0038] For FPGA implementations, hardware description languages ​​such as VHDL or Verilog can be used to reconfigure the logic. This allows users to program the control logic unit U to meet specific application requirements without significant hardware changes. Optimization techniques have been incorporated into the design of the control logic unit U to ensure minimal propagation delay and reduced power consumption.

[0039] The control logic unit U may also include standard communication interfaces, such as SPI (Serial Peripheral Interface) or I2C (Internal Integrated Circuit), to facilitate convenient communication with other digital components of the turbine 1.

[0040] One embodiment of actuator 49 features an electric motor coupled to a gearbox (not shown). This configuration allows for a reduced rotational speed of the motor while increasing its torque, thereby providing the necessary force to move the movable blades 442 of the inlet guide vane 44. Depending on the specific advantages desired in terms of torque transmission, the gearbox can be designed using various configurations, such as spur gear, worm gear, or planetary gear systems.

[0041] Another implementation integrates a feedback system (such as a potentiometer or rotary encoder) into the actuator. These components allow continuous monitoring of the position of the movable blade 442, providing real-time data to the control unit. Using this information, the actuator can precisely adjust the position of the inlet guide vane 44, ensuring that the blade is always in the optimal position for the current operating conditions. This feedback mechanism not only improves efficiency but also extends the blade's lifespan by preventing excessive wear and tear.

[0042] In another embodiment, the electric actuator 49 is designed with a fault protection mechanism. In the event of a power outage or system failure, the actuator can move the blade 44 to a predetermined "safe" position. This feature ensures that the machine can be safely stopped.

[0043] Considering actuator control, some implementations can incorporate advanced algorithms in the control unit U and control strategies in the onboard microcontroller. By analyzing data from the feedback system and other sensors, the control logic unit U can dynamically adjust the inlet blade position in real time to meet changing operational requirements.

[0044] These actuators 49 move the movable blades 442 of the inlet guide vane 44, causing the movable blades 442 to rotate about a specified axis, thereby helping to fine-tune the entry angle of the fluid on the impeller 3.

[0045] Furthermore, the rod portion 441 of each inlet guide vane 44 engages with the bushing 443. For example... Figure 3 As shown, rod 441 is constrained by bolt 444. Movable blade 442 rotates and is associated with rod 441. The axis of each rod 441 is perpendicular to the axial direction A of the inlet assembly 4. Specifically, considering the cross-section of the flow path pipe 42, a circle is obtained, in which the axial direction A passes through the center, and each rod 441 is located on the radius of this circle.

[0046] Actuator 49 can be of two different types, as detailed herein. Figure 3As illustrated, the actuator 49 of the first type is characterized by an electric ring construction. This design allows for seamless engagement with the rod 441. The electric ring 49 surrounds the rod 441 and engages directly with the rod, thereby facilitating the smooth and efficient transmission of rotational motion to the rod 441.

[0047] Upon startup, the electric ring 49 rotates, which in turn causes the engaged rod 443 to rotate, thereby enabling the rotation of the movable blade 442 of the inlet guide vane 44.

[0048] Figure 6 and Figure 7 The second type of actuator 49 illustrated operates by engaging with a lever 491. Unlike the electric ring configuration, this design utilizes a different mechanical interface to actuate the associated system or component. In this configuration, the actuator is strategically positioned to apply force to the lever, thereby actuating the rod 443 of the inlet guide vane 44 and the movable blade 442. This engagement with the lever allows for precise control and operation.

[0049] Continue to refer to Figure 3 or Figure 6 The flow path duct 42, which varies only depending on the actuator implemented, can be seen as being adapted to guide and optimize the flow path F of air or fluid before it reaches the impeller 3. The flow path duct 42 has a tapered design toward its rear section (i.e., the section facing the impeller 3).

[0050] Conversely, the front of the duct is wider, allowing for the intake of a large volume of air. As the air advances through the flow path duct 42, it encounters a tapered section that gradually narrows towards the rear. This tapered design is based on the principles of fluid dynamics, where the velocity increases when a given volume of fluid or gas (in this case, air) is forced through a gradually decreasing cross-sectional area. Therefore, the air accelerates as it passes through the narrowing duct passage.

[0051] This acceleration of the airflow offers several advantages. In fact, it ensures a high-speed, uniform flow path F to the impeller 3, thereby improving its efficiency and performance. Furthermore, the tapered design helps to ensure a uniform pressure distribution along the pipe length, thus preventing potential low-pressure areas that could lead to cavitation or other undesirable aerodynamic phenomena.

[0052] In the illustrated embodiment, the inlet assembly 4 includes a apex 46 arranged along the axial direction A, and one or more fixed blades 47.

[0053] When combined with the fixed blade 47, the tip 46 can optimize fluid flow. Each fixed blade can interact with the fluid flow path F to produce specific technical effects that further enhance machine performance; its design properties are not yet detailed.

[0054] The fixed blade 47 has the function of separating the flow path F before it reaches the inlet guide vane 44, and the structural function of connecting the tip 46 to the stator element 43.

[0055] The number of fixed blades 47 is variable. In the described embodiment (reference...) Figure 4 The fixed number of blades is five, but different numbers can be considered.

[0056] The fixed blades 47 also have a structural function of supporting the tip 46 (such fixed blades 47 act as struts). The fixed blades 47 have an aerodynamic function because they direct gas toward the corresponding movable blades 442.

[0057] To suppress turbulence and achieve greater fluid flow control, some embodiments may include a guide element 48 located within the inlet assembly 4 and specifically arranged along the axial direction A between the tip 46 and the impeller inlet 31. The guide element 48 guides the fluid to minimize deviated turbulence, thereby ensuring a smoother transition into the impeller inlet 31. In another embodiment, the guide element 48 includes a cylindrical portion 481 and an extended section 482 adjacent to the impeller inlet 31.

[0058] During operation, as fluid enters through inlet 41, it initially encounters the tip 46 and stationary blades 47. These components further regulate the flow, ensuring smooth and controlled delivery to impeller 3.

[0059] Additionally, as described above, the flow path F accelerates when passing through the flow path conduit 42, potentially leading to turbulence. To reduce this turbulence, in addition to the action of the tip 46 and the fixed blades 47, the inlet guide vanes 44 also deflect the fluid flow path F. Specifically, the movable blades 442 of the inlet guide vanes 44 can be adjusted, thereby affecting the flow direction of the fluid and the angle of incidence at the inlet 31 on the impeller 3. This adjustable system ensures optimal interaction between the fluid and the impeller 3, thereby maximizing or improving the efficiency of the impeller 3 itself.

[0060] Adjusting the airflow angle at the inlet of impeller 3 has several beneficial effects. Specifically, modifying the airflow angle helps optimize the efficiency of impeller 3 by ensuring that air enters the blades at the optimal angle, reducing losses due to drag and friction.

[0061] Furthermore, adjusting the airflow angle can improve the pressure distribution on impeller 3, thereby enhancing performance and reducing wear on the impeller blades, thus extending the impeller's service life. Changing the airflow angle also allows for adjustment of the flow velocity through impeller 3. This is necessary in various applications where different flow velocities are required for different operations or conditions.

[0062] Another advantage of adjusting the airflow angle is that it improves the aerodynamic performance of the impeller 3 by reducing undesirable effects such as flow separation, turbulence, and eddies, thereby making operation smoother and more efficient.

[0063] On the other hand, the guiding element 48 controls and reduces the turbulence in the flow path F before it enters the impeller 3.

[0064] When the fluid finally reaches the impeller 3, its rotational motion accelerates and pressurizes it. The fluid then exits the turbine 1 at a higher pressure, ready for its intended application with greater compression. The inlet guide vanes 44 and guiding elements 48 allow laminar flow conditions to be maintained and prevent turbulence, such that the shape of the flow path duct 42 ensures that the air remains streamlined, thereby minimizing energy loss and maximizing the performance of the impeller 3.

[0065] advantage

[0066] A key benefit of this disclosure is the increased blade density. Higher blade density translates into stronger and more resilient blades, capable of withstanding various operating pressures. This enhances the overall integrity and durability of the machine.

[0067] This disclosure also provides better control over machine functions. It facilitates precise control over the flow of the medium and the angle at which the medium enters the impeller. This means that the machine can operate consistently under optimal conditions, thereby providing a level of performance that is both efficient and reliable.

[0068] Furthermore, the proposed design increases the machine's downsizing range. This expanded range means the machine can operate efficiently under a wider range of conditions, adapting to different needs and ensuring greater flexibility.

[0069] Another advantage of this disclosure is that it enables the management of machine operation even using a single inlet guide vane. This simplifies the control mechanism, making it easier to operate and more cost-effective in terms of maintenance and potential replacement.

[0070] While various aspects of the invention have been described with reference to specific embodiments, it will be apparent to those skilled in the art that numerous modifications, variations, and omissions are possible without departing from the spirit and scope of the claims. Furthermore, unless otherwise specified herein, the sequence or order of any process or method steps may be altered or rearranged according to alternative embodiments.

[0071] Reference has been made in detail to embodiments of this disclosure, one or more examples of which are illustrated in the accompanying drawings. Each example is provided by way of interpretation and not limitation of this disclosure. Indeed, it will be apparent to those skilled in the art that various modifications and variations can be made to this disclosure without departing from its scope or substance. Throughout this specification, references to “one embodiment” or “some embodiments” mean that a particular feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment of the disclosed subject matter. Therefore, the phrases “in one embodiment” or “in some embodiments” appearing in various places throughout this specification do not necessarily refer to the same embodiment. Furthermore, in one or more embodiments, a particular feature, structure, or characteristic may be combined in any suitable manner.

[0072] When describing the elements of various embodiments, the articles “a,” “the,” and “the” are intended to mean that one or more of the elements are present. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that additional elements may be present in addition to those listed.

Claims

1. A turbine (1) for compressing fluids such as air, carbon dioxide (CO2), hydrogen (H2), and / or methane (CH4), said turbine comprising: Accommodating the main body (2); Impeller (3), which is capable of rotating about an axial direction (A) to pressurize a gas flow path (F), is housed within the housing body (2); and An inlet assembly (4), which is housed in the housing body (2) and in airflow communication with the impeller (3), wherein the inlet assembly (4) comprises: Inlet (41), through which the airflow to be pressurized can enter; Flow path conduit (42), which is configured to direct fluid entering through the inlet (41) of the intake conduit (41) to the impeller (3). The inlet component (4) is characterized in that it comprises: Stator element (43), which defines the flow path duct (42) through which airflow can pass; One or more inlet guide vanes (44), wherein each inlet guide vane (44) includes: The rod (441) is rotatably connected to the stator element (43), and Movable blade (442), said movable blade being fixed to said rod (441); and One or more fixed blades (47), each fixed blade corresponding to a corresponding guide vane (44) arrangement; The one or more inlet guide vanes (44) and the one or more fixed vanes (47) are arranged to adjust the angle of incidence of the fluid flow path (F) before it enters the impeller (3).

2. The turbine (1) according to claim 1, wherein the inlet assembly (4) includes a head flange (45) that includes the stator element (43) and defines a circular inlet (451) for the airflow to enter, wherein the head flange (45) is fixed to the receiving body (2).

3. The turbine (1) according to any one of the preceding claims. The rod portion (441) of each inlet guide vane (44) is radially arranged in the stator element (43), and The inlet assembly (4) further includes an electric actuator (49) operatively coupled to a stationary portion to cause the stationary portion to rotate about a rotation axis (R) radially relative to the axial direction (A).

4. The turbine (1) according to claim 3, wherein each inlet guide vane (44) includes a rod portion (443), and The associated movable blade (442) pivots or rotates around the associated rod (443).

5. The turbine (1) according to claim 4, The rod (443) engages with the bushing (444), and the electric actuator (49) is an electric ring that engages with the rod (443); or The actuator (49) is operated by engaging with a lever (491) connected to the rod (443).

6. The turbine (1) according to any one of the preceding claims, wherein each fixed blade (47) corresponds to a corresponding guide vane (44) arrangement.

7. The turbine (1) according to any one of the preceding claims. The inlet assembly (4) includes a spire (46) arranged along the axial direction (A) into the flow path conduit (42), and Each fixed blade (47) has a first end (471) fixed to the tip (46) and a second end (472) fixed to the inner surface of the flow path pipe (42). Each fixed blade (47) has a section suitable for intercepting the flow path (F) and directing it to the corresponding movable blade (442).

8. The turbine (1) according to any one of the preceding claims, wherein the inlet assembly (4) includes a guide element (48) arranged along the axial direction (A). The guide element (48) has one end connected to the tip (46) and another end disposed at the inlet of the impeller (3). The guiding element (48) is designed to guide the flow path (F) to reduce turbulence of the fluid after the movable blades (442) of one or more inlet guide vanes (44) have deviated.

9. The turbine (1) according to any one of claims 7 or 8, wherein the guide element (48) has a main portion (481) and an end portion (482), the main portion having a cylindrical shape, and the end portion having a larger cross-section than the main portion (481) and being adapted to match the inlet (31) of the impeller (3).

10. The turbine (1) according to any one of claims 7 to 9, wherein the spire (46) and the guide element (48) are made of a single piece.

11. An entry component (4), comprising: Stator element (43), which defines a flow path duct (42) through which airflow can pass, and One or more inlet guide vanes (44), wherein each inlet guide vane (44) includes: A rod (441) rotatably connected to the stator element (43); and Movable blade (442), said movable blade being fixed to said rod (441), said rod engaging with bushing (443); and One or more fixed blades (47), each fixed blade corresponding to a corresponding guide vane (44) arrangement; The one or more inlet guide vanes (44) and the one or more fixed vanes (47) are arranged to adjust the incident angle of the fluid flow path (F) before it enters the impeller (3).

12. The inlet assembly (4) of claim 11, wherein the air intake duct (42) includes a head flange (45) that includes the stator element (43) and defines a circular inlet (451) for the airflow to enter, wherein the head flange (45) is fixed to the receiving body (2).

13. The inlet component (4) according to any one of claims 11 or 12. The fixed portion (441) of each inlet guide vane (44) is radially arranged in the stator element (43), and The inlet assembly (4) further includes an actuator (49) operatively coupled to the fixed portion to cause the fixed portion to rotate about a rotation axis (R) radially relative to the axial direction (A).

14. The inlet assembly (4) according to any one of claims 11 or 12, comprising a spire (46) arranged along the axial direction (A) into the flow path conduit (42), Each fixed blade (47) has a first end (471) fixed to the tip (46) and a second end (472) fixed to the inner surface of the flow path pipe (42).

15. The inlet assembly (4) according to any one of the preceding claims, comprising a guide element (48) arranged along the axial direction (A). The guide element (48) has one end connected to the tip (46) and another end disposed at the inlet of the impeller (3). The guiding element (48) is designed to guide the flow path (F) to reduce turbulence in the fluid after the movable blades (442) of the one or more inlet guide vanes (44) have deviated. The guide element (48) has a main portion (481) and an end portion (482), the main portion having a cylindrical shape, and the end portion having a larger cross-section than the main portion (481) and being adapted to match the inlet (31) of the impeller (3).

16. The turbine (1) according to claim 15, wherein the spire (46) and the guide element (48) are made of a single piece.

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