Stator for pump comprising primary vane and secondary vane

Abstract

The invention relates to a pump stator comprising a hub and a housing coaxial about a longitudinal axis, an axial inlet and an axial outlet, a first set of primary blades (50) and a second set of secondary blades (60), the generatrix of the primary blades (50) and secondary blades (60) extending substantially axially, the secondary blades (60) being circumferentially interposed between the primary blades (50), the leading edges of the primary blades (50) being on a single first transverse plane. Furthermore, the leading edge of the secondary blade (60) is positioned on a second transverse plane parallel to the first transverse plane, which second transverse plane is located in the direction of said axial outlet at a first predetermined distance from the first transverse plane, which first predetermined distance is between 0.1 and 0.3 times the axial length (Lm) of the primary blade (50). The invention also relates to a pump having such a stator.

Description

Technical Field

[0001] This invention relates to the field of fluid compression or pumping devices, and more particularly to a stator for a fluid compression or pumping device.

[0002] A compression unit typically comprises one or more compression stages. Each compression stage includes at least one moving part with a rotating wheel (also referred to as a "rotor" or "impeller") and at least one stationary part (a straightener, also referred to as a "stator" or "diffuser"). These components may be installed inside the compression unit housing.

[0003] The stator is located downstream of the impeller and is used to straighten the fluid flow exiting the impeller, which is driven to rotate by the impeller. Its purpose is to feed the next compression stage (another rotating wheel downstream of the stator) or to use the fluid flow directly. The stator is used to convert the kinetic energy of the fluid into potential energy. To do this, the stator typically includes blades.

[0004] The stator is static, meaning it is fixed relative to the outer casing of the compressor, while the rotating wheels are movable and rotate about a longitudinal axis. The purpose of these rotating wheels is to increase the kinetic and potential energy of the fluid. They are typically attached to the rotating shaft and usually include blades.

[0005] More specifically, the present invention relates to a pump and a pump stator designed to pump compressible fluids, particularly CO2. Background Technology

[0006] Figure 1 It was obtained from patent application US2018 / 106270 AA. The figure illustrates a system including at least one or more compression stages ( Figure 1 An example of a multiphase pump (with only one stage shown) is illustrated, each stage comprising an impeller 1 and a stator 2. The impeller is attached to a hub 10. The impeller 1 may include multiple blades 3, and the stator 2 may include multiple blades 4. In this figure, the direction of fluid flow is indicated by arrow S.

[0007] Due to the geometry of certain compression devices, the flow can form a very large angle (e.g., approximately 60 to 70 degrees) with the axis of rotation of the device at the dynamic outlet of the rotating wheel. The geometry of the stator attempts to limit the residual angle with the axis of rotation of the device at the stator outlet.

[0008] Patent application US2018 / 106270 AA relates to a pump stator. The stator may consist of two consecutive parts axially positioned one behind the other and separated by an intermediate piece forming an axial distance between the two consecutive parts. However, the space formed between the upstream blades of the upstream part of the stator and the downstream blades of the downstream part of the stator causes a significant performance loss.

[0009] Patent application CN 115 388 038 A relates to a stator for a centrifugal compressor having a radial inlet and an axial outlet. The stator includes two sets of blades.

[0010] The object of the present invention is to improve the performance of the stator of a pump (such as a multiphase pump) by limiting separation phenomena, particularly for compressible fluids such as CO2, wherein the fluid flow is substantially axial along the pump and stator. Summary of the Invention

[0011] This invention relates to a pump stator comprising: a hub and a housing coaxially about a longitudinal axis; an axial inlet for introducing fluid into the stator and an axial outlet for discharging fluid from the stator; a first series of main blades and a second series of auxiliary blades, the main blades and auxiliary blades extending radially from the hub to the housing, the generatrices of the main blades and auxiliary blades extending substantially axially; the auxiliary blades being circumferentially inserted between the main blades; and the leading edges of the main blades being on the same first transverse plane. Furthermore, the leading edges of the auxiliary blades are positioned on a second transverse plane parallel to the first transverse plane, the second transverse plane being axially positioned along the direction of the axial outlet at a first predetermined distance from the first transverse plane, the first predetermined distance being between 0.1 and 0.3 times, preferably between 0.15 and 0.25 times, the axial length of the main blades.

[0012] Preferably, the axial length of the secondary blade is less than or equal to the axial length of the main blade.

[0013] Advantageously, the trailing edge of the secondary blade forms a third transverse plane, which is positioned at a second predetermined distance from the fourth transverse plane formed by the trailing edge of the main blade. This second predetermined distance is between -0.3 times and +0.3 times the axial length of the main blade, preferably between -0.1 times and +0.1 times, and preferably, the second predetermined distance is zero.

[0014] Advantageously, the secondary blades are offset circumferentially from the main blades directly in front of them by a certain angle, which is between 0.2 and 0.5 times, preferably between 0.25 and 0.35 times, the circumferential angle offset of the main blades.

[0015] Preferably, the ratio between the axial outlet cross section and the axial fluid inlet cross section is between 0.5 and 2.5, and more preferably between 0.5 and 1.5.

[0016] According to an advantageous configuration of the invention, the ratio between the axial length of the main blade and the outer radius at the leading edge of the main blade is between 0.36 and 1.80, preferably between 0.65 and 1.64.

[0017] According to a preferred variant of the invention, the outer diameter of the main blade and / or auxiliary blade decreases from the axial inlet to the axial outlet.

[0018] Advantageously, the inner diameter of the main blade and / or auxiliary blade decreases from the axial inlet to the axial outlet.

[0019] Preferably, the main blades are offset two at a time along the circumferential direction by a circumferential angular deviation. This essentially verifies that: in It is the circumferential angle deviation of the main blade, which basically corresponds to the circumferential angle deviation generated between the leading and trailing edges of each main blade; ALR: The ratio between the axial length of the main blade and the outer radius at the leading edge of the main blade, where a and b are predetermined values.

[0020] The present invention also relates to a pump, preferably a multiphase pump, comprising an outer casing, an axially arranged series of stationary and rotating parts inside the outer casing, a first axial inlet opening for introducing fluid into the pump, and a second axial outlet opening for discharging fluid from the pump. At least one stationary part comprises a stator as described above, preferably the outer casing corresponding to a stator housing.

[0021] Preferably, the outer casing includes at least one portion having an inner surface with a strictly decreasing inner diameter along the direction of axial fluid flow through the pump, and preferably, the outer casing includes several portions, each having an inner surface with a strictly decreasing inner diameter along the direction of axial fluid flow through the pump. Attached Figure Description

[0022] Other features and advantages of the stator and / or pump according to the invention will become apparent from the following description of non-limiting examples of embodiments with reference to the accompanying drawings.

[0023] Figure 1 An example of a multiphase pump according to the prior art is shown (as already described).

[0024] Figure 2 A first example of a pump according to the present invention is shown.

[0025] Figure 3 A second example of a pump according to the invention is shown.

[0026] Figure 4 A longitudinal view of the pump stator according to the present invention is shown.

[0027] Figure 5The illustration shows a view of a pump stator with certain parameters according to the present invention, interpreted along the circumferential direction.

[0028] Figure 6 The illustration shows a device with the present invention having the following features: Figure 5 A view illustrating the additional parameters of the pump stator along the circumferential direction, in addition to the parameters of the pump stator itself.

[0029] Figure 7 The figure illustrates the performance curves for the pump stator according to the invention as a function of the axial offset of the leading edge of the secondary blade relative to the leading edge of the main blade.

[0030] Figure 8 The figure illustrates the performance curve of the pump stator according to the present invention as a function of the circumferential angular offset of the leading edge of the secondary blade relative to the leading edge of the main blade.

[0031] Figure 9 Figure a) illustrates the outline of the pump stator hub and casing along the longitudinal axis, and Figure b) illustrates the outline of the blades on the various parts that connect to the hub and casing.

[0032] Figure 10 The illustration shows a comparison of the axial velocity fields in the longitudinal plane of a prior art stator (a) and a stator (b) of the present invention. Detailed Implementation

[0033] The terms "axial" and "axially" generally mean along or parallel to the longitudinal axis, while the terms "radial" and "radially" generally mean perpendicular to the longitudinal axis. For example, axial length refers to a distance measured along or parallel to the longitudinal axis, and radial length corresponds to a distance measured radially (i.e., perpendicular to the longitudinal axis). Referring to the accompanying drawings, the terms "top," "bottom," "above," "below," and variations thereof are used for convenience without impairing their spatial positioning in use and do not require any particular orientation of the component.

[0034] In this document, the term "fluid compression device" refers to compressors and pumps, which are designed to compress or pump fluids, respectively. These devices can be surface, subsea, or downhole (i.e., in underground formations).

[0035] The terms "upstream" and "downstream" refer to the direction of fluid flow through the stator or pump.

[0036] The leading edge is the fluid-facing edge of the blade. It splits the fluid reaching the upstream of the blade into two flows, one flowing along one side of the blade (e.g., the upper surface called the dome) and the other flowing along the opposite side (e.g., the lower surface).

[0037] The trailing edge is the edge of the blade opposite the leading edge. At the trailing edge, two flows that separated at the leading edge can merge again to form a single flow. In other words, the leading edge is at the upstream end of the blade, and the trailing edge is at the downstream end of the blade.

[0038] The generatrix of a blade is its centerline, which is located at equidistant points from both the upper (arched) and lower (inner) surfaces. It is typically curved and extends substantially axially.

[0039] The upper surface (arched back) is the convex outer surface of the blade, while the lower surface (inner arc surface) is the concave inner surface of the blade.

[0040] For the purposes of this description, the transverse plane is a plane orthogonal to the longitudinal axis of the stator or pump.

[0041] This invention relates to a stator (also referred to as a "rectifier" or "diffuser") for a pump, preferably a multiphase pump, the stator comprising: - A hub (or "inner hub") and a casing (also called "outer hub") that are coaxial around a longitudinal axis. - An axial inlet used to introduce fluid into the stator. - An axial outlet for discharging fluid from the stator. - First series of main blades - and the second series of auxiliary blades.

[0042] Therefore, in the stator of the present invention, the fluid flow extends substantially axially from the axial inlet to the axial outlet. Thus, this type of stator is suitable for pumps, such as so-called "multiphase" pumps, i.e., pumps capable of pumping multiphase fluids.

[0043] According to the invention, the main blade and the auxiliary blade extend radially from the hub to the casing, and the generatrices of the main blade and the auxiliary blade extend substantially axially. "Substantially axially" means that the blade and its generatrices are curved and therefore do not extend solely in the axial direction.

[0044] The main and secondary blades may preferably not have any openings (such as holes and / or grooves) in order to limit performance losses in the stator and pump. This is especially true when the purpose of the stator is to convert kinetic energy into potential energy, as openings would create turbulence.

[0045] Furthermore, the auxiliary blades are circumferentially distributed among the main blades. Therefore, the stator of the present invention includes as many main blades as the auxiliary blades, and comprises an alternating arrangement of main blades and auxiliary blades circumferentially. Thus, the distributed auxiliary blades serve to limit fluid separation between the main blades.

[0046] Furthermore, the leading edges of the main blades lie on the same first transverse plane; in other words, their projections onto the longitudinal axis form a single point on the longitudinal axis. Similarly, the leading edges of the secondary blades are positioned on a second transverse plane parallel to the first transverse plane. In other words, the projections of the leading edges of the secondary blades onto the longitudinal axis also form a single point on the longitudinal axis.

[0047] According to the invention, the second transverse plane is axially positioned along the direction of the axial outlet at a first predetermined distance from the first transverse plane, i.e., downstream of the first transverse plane. This first predetermined distance is between 0.1 and 0.3 times the axial length of the main blade, preferably between 0.15 and 0.25 times. This improves the pressure recovery coefficient C. p To improve the performance of the stator and thus the associated pump, the pressure recovery coefficient is defined as follows: in: ΔP statique The static pressure difference between the fluid at the axial outlet and the axial inlet. P dynamiquein Axial inlet fluid dynamic pressure P s,out The static pressure of the fluid at the axial outlet and the dynamic pressure of the fluid at the axial inlet. P s, in The static pressure of the fluid at the axial inlet P t, in Total fluid pressure at the axial inlet.

[0048] Therefore, the pressure recovery coefficient C p This reflects the stator's ability to convert dynamic pressure caused by the kinetic energy of the fluid into static pressure.

[0049] The higher this coefficient, the higher the stator's performance.

[0050] The position of the leading edge of the secondary blades relative to the leading edge of the main blades defines the stator trapping zone, which lies between the first and second transverse planes. Increasing this trapping zone increases the stator's potential operating range by reducing its sensitivity to high angles of attack. High angles of attack cause fluid to separate from the upper surface of the blades, thus blocking the diffuser inlet. With a large trapping area, the separated fluid can be transported more easily within the stator. Depending on the fluid's viscosity, significant separation can occur. This is especially true when the viscosity is relatively low, such as that of CO2.

[0051] The invention also maintains the stator's restoring capability by reducing the tangential velocity of the fluid leaving the rotor: the tangential velocity of the fluid is reduced at the stator outlet compared to the velocity of the fluid at the stator inlet.

[0052] Therefore, compared to a stator design without secondary blades, the stator of the present invention has fewer main blades. In other words, the stator has essentially the same total number of blades, but includes half that number of main blades and the other half of secondary blades. This increases the capture area upstream of the secondary blades, and then improves flow support in the stator thanks to the secondary blades.

[0053] According to one variation of the invention, the axial length of the secondary blades may be less than or equal to the axial length of the primary blades. This makes it possible to limit the size of the stator and achieve a good trade-off between the stator's desired performance, its compactness, and therefore its cost.

[0054] Preferably, the trailing edge of the secondary blade can form a third transverse plane, which is positioned at a second predetermined distance from the fourth transverse plane formed by the trailing edge of the main blade, and this second predetermined distance can then be between -0.3 times and +0.3 times, preferably between -0.1 times and +0.1 times, the axial length of the main blade. With the trailing edges of the main blade and the secondary blade close together, space requirements can be limited and good performance can be achieved.

[0055] Preferably, the second predetermined distance can be zero. In other words, the trailing edges of the main blades and the secondary blades are on the same transverse plane in order to limit the overall size of the stator while maximizing its performance.

[0056] According to one configuration of the invention, the secondary blades are circumferentially offset from the primary blade immediately preceding them in the circumferential direction (the circumferential direction is defined as from the leading edge to the trailing edge, and the orientation of the inner arc surface and the dome is the same for all primary and secondary blades) by an angle between 0.2 and 0.5 times, preferably between 0.25 and 0.35 times, the circumferential angular offset of the primary blade. In other words, the secondary blades are angled closer to the upper surface of the preceding primary blade rather than closer to the lower surface of the following primary blade. This configuration also improves the pressure recovery coefficient C as defined above. p Specifically, by limiting the possibility of separation on the upper surface of the main blade.

[0057] Advantageously, the ratio between the axial outlet cross-sectional area and the axial fluid inlet cross-sectional area can be between 0.5 and 2.5, preferably between 0.5 and 1.5. This is because an excessive increase in the outlet cross-sectional area will cause separation and thus a loss of performance, while an excessive decrease in the outlet cross-sectional area will reduce diffusion potential.

[0058] Advantageously, the ratio between the axial length of the main blade and the outer radius at the leading edge of the main blade can be between 0.36 and 1.80, preferably between 0.65 and 1.64, to ensure a good trade-off between performance and compactness. In fact, an excessively large ratio reduces compactness and also causes significant frictional losses on the blade. Conversely, an excessively small ratio improves compactness but forces excessive deflection (with significant curvature) over short distances, resulting in separation.

[0059] According to one embodiment of the invention, the outer diameter of the main blade and / or auxiliary blades can decrease from the axial inlet to the axial outlet. By reducing the diameter, the outlet cross-section is reduced, thereby allowing for better fluid compression. This is particularly advantageous in the case of compressible fluids such as CO2.

[0060] Advantageously, the inner diameter of the main blades and / or auxiliary blades can be reduced from the axial inlet to the axial outlet, such that the inner diameter on the axial outlet side is compatible, i.e., substantially equal to the inner diameter of the impeller downstream of the stator, in order to limit pressure losses that may result from sudden changes in cross-section.

[0061] Preferably, the main blades can be continuously offset in pairs along the circumferential direction by a circumferential angular offset. Thus, the following is basically satisfied: in It is the circumferential angular offset of the main blade, which basically corresponds to the circumferential angular offset produced between the leading and trailing edges of the blade in question (in this case, the main blade). ALR : The ratio between the axial length of the main blade and the outer radius at the leading edge of the main blade, where a and b are predetermined values.

[0062] a and b can be determined based on numerical simulations or experimental tests. For example, we can make... a=1.16 And b = 0.57.

[0063] The term "basically verified" means "as close as possible." This is because the number of blades must be an integer, and therefore the above equation can only be determined as close as possible given that integer.

[0064] Surprisingly, despite the many possible parameters for optimization and the complexity of numerical simulations and phenomena, this formulation based on the linearization of the OL parameters as a function of the ALR ratio makes it possible to obtain the optimal position.

[0065] Advantageously, the main blades can have similar generatrices, that is, the generatrices of different main blades can overlap.

[0066] Preferably, the secondary blades may also have similar generatrices, that is, the generatrices of different secondary blades may overlap.

[0067] Preferably, the main blade and the auxiliary blade may have at least partially similar generatrices: for example, when the trailing edge of the auxiliary blade is upstream of the trailing edge of the main blade, the generatrices of the auxiliary blade then overlap a portion of the generatrices of the main blade. Conversely, when the trailing edge of the auxiliary blade is downstream of the trailing edge of the main blade, the portion of the auxiliary blade generatrices located between the second transverse plane and the fourth transverse plane overlaps a portion of the main blade generatrices.

[0068] When the busbars have similar curvature (between the main blades and / or auxiliary blades), flow disturbances and therefore energy losses are limited.

[0069] The present invention also relates to a pump, preferably a multiphase pump, comprising an outer housing and an axially arranged series of compression stages within the outer housing. Each compression stage includes stationary and rotating parts.

[0070] The pump also includes a first axial inlet opening for introducing fluid into the pump and a second axial outlet opening for discharging fluid from the pump. Additionally, at least one stationary component (preferably each stationary component) includes a stator as described above.

[0071] The pump of this invention allows for the pumping of both multiphase and single-phase fluids, particularly compressible fluids, including CO2. The use of a stator as described above improves the pump's performance.

[0072] The pump casing can be used as the stator housing. In other words, the pump casing can advantageously correspond to the stator housing described above to limit the number of parts and simplify assembly.

[0073] Preferably, the outer casing may include at least one portion having an inner surface with a substantially decreasing inner diameter along the direction of axial fluid flow through the pump (i.e., the portion having a substantially decreasing inner diameter between the first axial inlet opening and the second axial outlet opening). This portion of the outer casing may be positioned particularly relative to the stator of the invention to improve compressibility. This is particularly advantageous in cases where the fluid is compressible (such as CO2).

[0074] Preferably, the outer casing may comprise several sections, each having an inner surface with a strictly decreasing inner diameter along the direction of axial fluid flow through the pump (i.e., the section has a strictly decreasing inner diameter between the first axial inlet opening and the second axial outlet opening). These sections of the outer casing may be positioned particularly relative to each of the pump stators to improve compressibility. This is especially advantageous in cases where the fluid is compressible (such as CO2).

[0075] For example, the outer casing may include a series of cylindrical members opposite each rotating part, and a portion opposite each stator, each portion having an inner surface with a strictly decreasing inner diameter (i.e., the portion has a strictly decreasing inner diameter between the first axial inlet opening and the second axial outlet opening). This configuration is preferred for efficiently compressing compressible gases (such as CO2).

[0076] Figure 2 A first example of a multiphase pump according to the present invention is illustrated schematically and non-limitingly.

[0077] The multiphase pump 100 (shown here in a longitudinal view, where Z(m) represents the pump's position along the longitudinal axis and R(m) represents the radial position) comprises several moving rotors Ro1, Ro2, and Ro3, and several stationary stators St1, St2, and St3. Therefore, the multiphase pump 100 here has three compression stages (but may include a different number of compression stages), each compression stage comprising a rotor followed by a stator.

[0078] The multiphase pump 100 also includes an outer casing 101 (in which various rotors Ro1, Ro2, and Ro3, and various stators St1, St2, and St3 are inserted), which can also serve as a stator housing. In this example, the outer casing is formed of a cylindrical member with a constant inner diameter.

[0079] Figure 3 A second example of a multiphase pump according to the invention is illustrated schematically and non-limitingly.

[0080] The multiphase pump 100 (shown here in a longitudinal view, where Z(m) represents the pump's position along the longitudinal axis and R(m) represents the radial position) comprises several moving rotors Ro1, Ro2, and Ro3, and several stationary stators St1, St2, and St3. Therefore, the multiphase pump 100 here has three compression stages (but may include a different number of compression stages), each compression stage comprising a rotor followed by a stator.

[0081] The flow through the pump begins at rotor Ro1, then stator St1, followed by rotor Ro2 and stator St2. The fluid is then passed through rotor Ro3 and stator St3. Therefore, in the diagram, the flow moves from left to right.

[0082] The multiphase pump 100 also includes an outer casing 101 (in which various rotors Ro1, Ro2, and Ro3, and various stators St1, St2, and St3 are inserted), which can also serve as a stator housing. In this example, the outer casing is formed of a cylindrical member having an inner diameter that decreases between the pump inlet and outlet. The outer casing includes a portion 102 opposite each stator St1, St2, and St3, in which the inner diameter decreases along the longitudinal axis in the direction of fluid flow through the pump. This configuration is particularly advantageous for highly compressible fluids such as CO2. This high compressibility results in a reduction in volume, which necessitates a reduction in cross-sectional area. Therefore, the rotors Ro1, Ro2, and Ro3 are adapted according to the reduction in the volumetric flow rate of the fluid.

[0083] Figure 4 A schematic and non-limiting view of the stator according to the invention in the longitudinal plane is shown. Z(m) represents the position along the longitudinal axis.

[0084] The leading edge 10 of the main blade is positioned upstream of the leading edge 20 of the secondary blade (where fluid flows from left to right), and the trailing edge 30 of the secondary blade is positioned upstream of the trailing edge 40 of the main blade (alternately, the trailing edge 30 of the secondary blade may be downstream of the trailing edge 40 of the main blade or positioned in the same transverse plane as the trailing edge 40 of the main blade).

[0085] The stator includes an inlet section A1 and an outlet section A2.

[0086] r 1h , r 1t , r 2h and R 2t These represent the hub radius at the stator inlet, the casing radius at the stator inlet, the hub radius at the stator outlet, and the casing radius at the stator outlet, respectively.

[0087] L d This indicates the axial length of the stator.

[0088] Figure 5 A schematic and non-limiting view of the stator according to the invention is shown. Z(m) represents the position along the longitudinal axis, and θ represents the evolution of the stator's azimuth angle.

[0089] The catchment area ZC is the region between the first transverse plane defined by the leading edge of the main blade 50 and the second transverse plane defined by the leading edge of the secondary blade 60. Therefore, it corresponds to the shaded area.

[0090] The first transverse plane is defined by the zLEm position, which corresponds to the position of the leading edge of the main blade 50 along the longitudinal axis.

[0091] The second transverse plane is defined by the zLEs position, which corresponds to the position of the leading edge of the secondary blade 60 along the longitudinal axis.

[0092] The trailing edge of the secondary blade 60 defines a third transverse plane, which corresponds to the zTEs position along the longitudinal axis.

[0093] The trailing edge of the main blade 50 defines a fourth transverse plane, which corresponds to the zTEm position along the longitudinal axis.

[0094] Therefore, the stator shown includes a circumferential series of main blades 50 and secondary blades 60 (only a portion of these blades are shown; of course, the stator includes as many main blades 50 as secondary blades 60, and the number of main blades 50 and secondary blades 60 depends on the application selected).

[0095] The main blade 50 has an axial length L m Furthermore, the secondary blade 60 has an axial length L s The axial length L s The axial length L is strictly less than 50 mm of the main blade. m .

[0096] The generatrices of the main blades 50 (represented by the dashed curves) are similar: they can be superimposed. The generatrices of the secondary blades 60 can be superimposed on the generatrices of the main blades 50 over an axial length Ls between a second transverse plane and a third transverse plane defined by the trailing edge of the secondary blades 60.

[0097] In addition, the main blades have an angular deviation of 50° between the leading and trailing edges of each main blade. Limited, and the stator is determined by the angular overlap. The angular overlap is defined as the distance between the trailing edge of the main blade 50 and the leading edge of the next main blade 50 (directly along the circumferential direction, from the arched blade to the lower surface).

[0098] Surprisingly, the amount of overlap at this angle... Defined by a linear equation based on the ALR parameter, which is the ratio between the axial length of the main blade and the outer radius at the leading edge of the main blade, as expressed below: For example, among them a = 1.16 and b =-0.57.

[0099] When pointing to (+), It can be positive: in this case, there is partial overlap of the main blades 50. When pointing to (-), it can also be negative: in this case, there is no overlap of the main blades, but there is an offset.

[0100] Numerical simulations have shown that, despite the numerous influential parameters in these complex multi-parameter simulations, this linearization makes it possible to obtain optimal results.

[0101] Angular deviation directly between two consecutive main blades The distance between the generatrices of these two blades can be defined as follows: Figure 6 A schematic and non-limiting view of a stator with other parameters according to the invention is shown. Z(m) represents the position along the longitudinal axis, and X=rθ represents the azimuth evolution of the stator, where r is the radial position and θ is the circumferential angle.

[0102] The first transverse plane is defined by position zLEm, which corresponds to the position of the leading edge of the main blade 50 along the longitudinal axis.

[0103] The second transverse plane is defined by position zLEs, which corresponds to the position of the leading edge of the secondary blade 60 along the longitudinal axis.

[0104] The trailing edge of the secondary blade 60 defines a third transverse plane, which corresponds to position zTEs along the longitudinal axis.

[0105] The trailing edge of the main blade 50 defines a fourth transverse plane, which corresponds to the position zTEm along the longitudinal axis.

[0106] Therefore, the stator shown includes a circumferential series of main blades 50 and secondary blades 60 (only a portion of these blades are shown; of course, the stator includes as many main blades 50 as secondary blades 60, and the number of main blades 50 and secondary blades 60 depends on the application selected).

[0107] The main blade 50 has an axial length L m Furthermore, the secondary blade 60 has an axial length L s The axial length L s The axial length L is strictly less than 50 mm of the main blade. m (However, the axial length L) s The length of the secondary blade can be greater than or equal to the axial length L of the primary blade. m ).

[0108] The generatrices of the main blades 50 (represented by the dashed curves) are similar: they can overlap. The generatrices of the secondary blades 60 can extend along their axial length L between the second and third transverse planes. s The third transverse plane overlaps with the generatrix of the main blade 50 and is defined by the trailing edge of the secondary blade 60.

[0109] In addition, the secondary blade 60 is defined by the axial offset of its leading edge.

[0110] and trailing edge These are relative to the leading and trailing edges of the main blade 50, respectively. Therefore, these axial offsets can be defined by the following formula: and : In addition, the secondary blade 60 is also offset by the circumferential distance between the upper surface of the main blade and the lower surface of the intermediate blade. The main blades are limited, and the circumferential distance between the main blades is also determined. ΔX m limited.

[0111] Numerical studies have shown that optimal results were obtained for the following criteria. - And preferably - And preferably - And preferably Figure 7 The illustration is schematic and not exhaustive, as previously shown in Figure 6 The pressure recovery coefficient C is a function of the SLES parameters defined in the description. p The curve.

[0112] The Ref curve represents the coefficient of restitution C of a prior art stator (without secondary blades, only primary blades). p The curve. The characteristics of the main blade are the same as those used in this invention (except that the number of blades is twice that of the main blade).

[0113] Sim points represent the results of numerical simulations of the stator from this invention, and FC curves represent the curves that best fit the Sim points.

[0114] The dashed Ref+10 curve represents the pressure recovery coefficient C of the Ref curve. pThe 10% increase. It can be seen that at least a 10% increase is achieved when the SLES parameter is between 0.1 and 0.3, and the increase is greatest when the SLES parameter is between 0.15 and 0.25.

[0115] This increase has little or no effect on the fluid outlet angle, which means that the fluid flow recovery performance can be maintained.

[0116] Figure 8 The illustration is schematic and without limitation depicting the previous... Figure 6 The pressure recovery coefficient C, a function of the SCP parameters defined in the description. p The curve.

[0117] The Ref curve represents the coefficient of restitution curve of a prior art stator (without secondary blades, only main blades). The characteristics of the main blades are the same as those used in this invention (except that the number of blades is twice that of the main blades).

[0118] The CFD_points represent the results of numerical simulations of the stator from this invention, and the black curve represents the curve that best fits the CFD_points.

[0119] The figure shows the gain when the SCP parameter is less than 0.5, and the more significant gain when the SCP parameter is between 0.25 and 0.35.

[0120] Figure 9 Examples of the hub and casing profiles and blade profiles of the stator according to the invention are shown in an illustrative and non-limiting manner.

[0121] Figure a) illustrates the outlines of hub P1 (black curve) and casing P2 (light gray) as a function of position Z (m) along the longitudinal axis and as a function of radial position R (m).

[0122] Figure b) illustrates the profiles of the main blade at hub P1 and shroud P2 as a function of position Z (m) along the longitudinal axis and as a function of circumferential position X (m), which depends on the azimuth angle and radial position.

[0123] The table below summarizes the geometric data for the various parameters defined in this description and determined by the profiles of these main blades. (rad) (m) (m) ALR P1 0.840 0.143 0.110 0.77 P2 0.604 0.143 0.110 0.77

[0124] The stator of the present invention includes, for example, 13 main blades and 13 auxiliary blades.

[0125] The secondary blades are defined by the following parameters, which are also defined in the description above. SLES STES SCP 0.2 0. 0.3

[0126] Example The stator of the present invention, particularly having the features described above, Figure 9 The stator with the described parameters is compared with a stator of the prior art. For the stator of the prior art, the main blades are the same in terms of their characteristics, and for the stator of the prior art, the number of main blades is twice the number of main blades of the stator of the present invention.

[0127] Numerical simulations have the following input conditions: - The fluid is CO2; - The inlet pressure in the stator is 23 bar (i.e., 2.3 10). 6 Pa); - The density of the fluid is: 1061.89 kg / m³ 3 ; - The viscosity of the fluid is: 1.5567 10 -4 Pas.; - The flow angle at the stator inlet is 71.14°; - The mass flow rate at the stator inlet is 31.7 kg / s.

[0128] The pressure coefficient indicates the stator's ability to convert dynamic flow pressure into static pressure. The outlet angle provides information about its ability to correct DC flow (return it to the axial direction) for the next pump stage. The addition of secondary vanes will increase the pressure recovery coefficient (C). p The pressure recovery coefficient (C) increased by more than 38% (from 0.52 to 0.72), thus demonstrating the stator's effective ability to convert dynamic flow pressure into static pressure. Compared to existing technologies without secondary blades, the fluid outlet angle is maintained within + / -10%, ensuring adequate flow straightening. p The significant improvement can be directly attributed to the modification of the flow topology within the stator of the present invention, which is achieved by shifting the leading edge of the secondary blades downstream of the leading edge of the primary blades.

[0129] Figure 10 The figures illustrate longitudinal views of the axial velocity fields of a prior art stator (Figure (a)) and a stator of the present invention (Figure (b)). In Figure (a), low-velocity regions 210 and 220 associated with flow separation can be observed. In Figure (b), a significant reduction in the low-velocity regions (and therefore a reduction in flow separation) can be seen by using the auxiliary blades according to the present invention.

Claims

1. A pump stator (St1, St2, St3), comprising: A hub and housing coaxial around a longitudinal axis, an axial inlet (A1) for introducing fluid into the stator and an axial outlet (A2) for draining the fluid from the stator, a first set of main blades (50) and a second set of auxiliary blades (60), the main blades (50) and auxiliary blades (60) extending radially from the hub to the housing, the generatrices of the main blades (50) and auxiliary blades (60) extending substantially axially, the auxiliary blades (60) being circumferentially sandwiched between the main blades (50), the leading edges (10) of the main blades (50) being on the same first transverse plane, characterized in that the leading edges (20) of the auxiliary blades (60) are positioned on a second transverse plane parallel to the first transverse plane, the second transverse plane being axially positioned along the direction of the axial outlet (A2) at a first predetermined distance (δz) from the first transverse plane. TE At the first predetermined distance (δz) TE Between the axial length (L) of the main blade (50) m The ratio is between 0.1 and 0.3 times, preferably between 0.15 and 0.25 times.

2. The pump stator (St1, St2, St3) according to claim 1, wherein, The axial length (L) of the secondary blade (60) s The axial length (L) of the main blade (50) is less than or equal to that of the main blade (50). m ).

3. The pump stator (St1, St2, St3) according to any one of the preceding claims, wherein, The trailing edge (30) of the secondary blade (60) forms a third transverse plane, which is positioned at a second predetermined distance (δz) from the fourth transverse plane formed by the trailing edge (40) of the main blade (50). TE At the second predetermined distance (δz) TE ) between the axial length (L) of the main blade (50) m The distance is between -0.3 times and +0.3 times, preferably between -0.1 times and +0.1 times, and preferably, the second predetermined distance (δz) is between -0.3 times and +0.3 times. TE The value is zero.

4. The pump stator (St1, St2, St3) according to any one of the preceding claims, wherein, The auxiliary blades (60) are offset circumferentially from the main blades (50) directly in front of them along the circumferential direction by a certain angle, the angle being the circumferential angular offset of the main blades (50) by Δθ. mis The ratio is between 0.2 and 0.5 times, preferably between 0.25 and 0.35 times.

5. The pump stator (St1, St2, St3) according to any one of the preceding claims, wherein, The ratio between the axial outlet region (A2) and the axial inlet region (A1) of the fluid is between 0.5 and 2.5, preferably between 0.5 and 1.

5.

6. The pump stator (St1, St2, St3) according to any one of the preceding claims, wherein, The axial length (L) of the main blade (50) m The ratio between the outer radius of the blade and the outer radius at the leading edge of the main blade is between 0.36 and 1.80, preferably between 0.65 and 1.

64.

7. The pump stator (St1, St2, St3) according to any one of the preceding claims, wherein, The outer diameter of the main blade (50) and / or the secondary blade (60) decreases from the axial inlet (A1) to the axial outlet (A2).

8. The pump stator (St1, St2, St3) according to any one of the preceding claims, wherein, The inner diameter of the main blade (50) and / or the secondary blade (60) decreases from the axial inlet (A1) to the axial outlet (A2).

9. The pump stator (St1, St2, St3) according to any one of the preceding claims, wherein, The main blade (50) is continuously offset by two circumferential angular deviations along the circumferential direction. This essentially verifies that: and in It is the circumferential angle deviation of the main blade, which basically corresponds to the circumferential angle deviation generated between the leading and trailing edges of each main blade (50); ALR: The axial length (L) of the main blade (50) m The ratio between the outer radius of the blade (50) and the leading edge of the main blade (50), and a and b are predetermined values.

10. A pump (100), preferably a multiphase pump, the pump comprising an outer casing (101), an axially arranged series of fixed and rotating parts (Ro1, Ro2, Ro3) inside the outer casing (101), a first axial inlet opening for allowing fluid to enter the pump, and a second axial outlet opening for allowing the fluid to exit the pump, wherein, At least one fixed component includes a stator (St1, St2, St3) according to any one of the preceding claims, preferably the outer casing (101) corresponds to the stator housing.

11. The pump (100) according to the preceding claim, wherein, The outer casing (101) includes at least one portion (102) having an inner surface with a strictly decreasing inner diameter in the direction of axial flow of fluid through the pump (100). Preferably, the outer casing (101) includes several portions (102), each having an inner surface with a strictly decreasing inner diameter in the direction of axial flow of fluid through the pump (100).

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