High-gas-content spiral axial flow type gas-liquid multiphase pump impeller

Abstract

The invention discloses a high-gas-content spiral axial flow type gas-liquid multiphase pump impeller which comprises a hub, blades and a rim, a plurality of arc-shaped grooves are formed in the outer wall of the hub, a plurality of arc-shaped protrusions are arranged on the inner wall of the rim, the blades comprise the first-class blades and the second-class blades which are alternately arranged, and the first-class blades and the second-class blades are arranged in a staggered mode. The first-class blades and the second-class blades adopt airfoils with inflexion characteristics in the area close to the hub, a protruding curved surface is arranged on the suction surface of the tail end of each second-class blade, a convergent flow channel is formed in each first-class blade, an inlet of each flow channel is located in the maximum thickness position of the protruding curved surface, and an air collection cavity is formed in the hub on the suction surface side of the tail end of each first-class blade. According to the spiral axial flow type gas-liquid multiphase pump, through a set of multi-assembly cooperative flow control system, the gas phase gathering process is restrained and intervened from the source, and the problem that a flow channel of the spiral axial flow type gas-liquid multiphase pump is blocked under the high gas containing rate is systematically solved.

Description

Technical Field

[0001] The present invention relates to a gas-liquid mixed transportation pump, especially an impeller of a high gas content helical axial flow gas-liquid mixed transportation pump. Background Art

[0002] In the fields of oil and gas extraction, chemical transportation, etc., the helical axial flow gas-liquid mixed transportation pump is the core equipment for simultaneously processing gas-phase and liquid-phase media. However, under the condition of high gas content, the gas-phase medium is driven by centrifugal force and inverse pressure gradient, continuously agglomerates and periodically detaches at the trailing edge of the suction surface of the moving blade row, forming serious intermittent flow channel blockage. This process causes large-amplitude and low-frequency severe pulsations in the flow rate and outlet pressure of the pump, not only resulting in flow instability characteristics similar to rotating stall in the pump unit, but also triggering serious water hammer and pressure oscillations in the downstream riser transportation system, constituting significant potential safety hazards for safe operation. Summary of the Invention

[0003] The purpose of the present invention is to provide an impeller of a high gas content helical axial flow gas-liquid mixed transportation pump to solve the technical problem of flow channel blockage in the existing gas-liquid mixed transportation pump.

[0004] The technical solution adopted by the present invention to solve its technical problems is: an impeller of a high gas content helical axial flow gas-liquid mixed transportation pump, including a hub, blades and a rim. The radius of the outer wall of the hub is R3, and the radius of the inner wall of the rim is R4. A number of arc-shaped grooves are provided on the outer wall of the hub, and a number of arc-shaped protrusions are provided on the inner wall of the rim. The centers of the grooves, protrusions and the hub are located on the same straight line. Adjacent two grooves are connected by a fillet. The blades include type-one blades and type-two blades, and the type-one blades and type-two blades are arranged alternately in sequence. The number of the type-one blades and type-two blades is the same, and each is at least two. The included angles of the type-one blades and type-two blades are both greater than 120°. The relative height in the radial direction is H, where H = 0 corresponds to the radius R3 of the outer wall of the hub, and H = 1 corresponds to the radius R4 of the inner wall of the rim. When H ≤ 0.25, both the type-one blades and type-two blades are reverse-curved airfoil structures with a concave front and a convex back. A convex curved surface is provided on the suction surface at the end of the type-two blades. When H ≥ 0.5, both the type-one blades and type-two blades are high-lift-drag airfoils without reverse-curved characteristics. When 0.25 < H < 0.5, the reverse-curved airfoil structures of the type-one blades and type-two blades smoothly transition to high-lift-drag airfoil structures. A convergent channel is provided on the type-one blades. The inlet of the channel opens on its pressure surface, and the outlet opens on its suction surface. In the flow direction, the inlet of the channel is located at the maximum thickness of the curved surface protrusion. A gas collection chamber is provided on the hub on the suction surface side at the end of the type-one blades. A jet hole is provided on the hub on the suction surface side in the middle of the type-two blades. The jet hole and the gas collection chamber are connected inside the hub.

[0005] Further improvement: When the curvature radii of the groove and the protrusion are R1, the chord length is C, the depth is h, and the central angle is α1, the following geometric relationship is satisfied: , and 0.13 < h / C < 0.17; α1 = 2arcsin(C / 2R1), and 45° < α1 < 65°, the fillet radius R2 = (0.05 - 0.15)R1, and the centers of the groove, the protrusion, and the hub are located on the same straight line.

[0006] Further improvement: The included angle between the center line of the channel and the tangent direction of the suction surface profile of the first type of blade is α2 = 10° - 20°, the position of the center line of the channel in the radial direction is 0.1 < H < 0.15, and the diameter of the channel inlet , where Q is the flow rate of the pump, ΔP is the pump boost value, ρ is the liquid phase density, the amplification factor k = 0.2 - 0.55, the split ratio β = 0.02 - 0.10, the flow coefficient C d = 0.6 - 0.75, and the outlet diameter D2 = (0.7 - 0.8)D1.

[0007] Further improvement: The gas collecting chamber is elliptical on the developed surface of the hub, the long axis direction of the gas collecting chamber is consistent with the chord direction of the blade, and the volume of the gas collecting chamber , R3 is the radius of the hub, R4 is the radius of the inner wall of the rim, L3 is the axial length of the impeller, Z is the number of blades, and the gas phase retention coefficient k v = 0.05 - 0.15, the chord length distance from the leading edge of the gas collecting chamber to the leading edge of the first type of blade is L2 = (0.65 - 0.75)L1, and the diameter of the jet hole D3 = (1.1 - 1.4)D1, where L1 is the chord length of the blade and D1 is the diameter of the channel inlet.

[0008] Advantages of the present invention: Both the hub and the rim adopt a convex-concave wavy structure, generating an additional curvature centrifugal force in the axial flow direction that is opposite to the direction of the rotational centrifugal force. This force协同 with the Coriolis force to weaken the driving force for the gas phase to transport towards the hub from the root, effectively suppressing gas-liquid separation and aggregation.

[0009] By alternately arranging the first type of blades and the second type of blades, a multi-component collaborative flow control system is formed, completely breaking the circumferential symmetry of the impeller. When the flow deteriorates in a local flow channel, the different blade configurations can prevent the synchronous propagation of disturbances in the circumferential direction, decomposing the low-frequency and global pressure fluctuations that are prone to occur in the traditional design into high-frequency and localized non-periodic disturbances. Such disturbances have dispersed energy and are more easily dissipated, suppressing and intervening in the gas phase aggregation process from the root, systematically solving the problem of flow channel blockage in the helical axial flow gas-liquid mixed transport pump under a high gas content rate, and effectively preventing the problem of flow channel blockage. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a schematic structural diagram of the present invention.

[0011] Figure 2 It is a cross-sectional view of the hub and the rim of the present invention.

[0012] Figure 3 It is the present invention Figure 2 A partial schematic diagram at position E in it.

[0013] Figure 4 It is a planar schematic diagram after the hub of the present invention is unfolded.

[0014] Figure 5 It is the present invention Figure 4 A partial schematic diagram at position F in it.

[0015] Figure 6 It is a schematic structural diagram of the channel of the present invention.

[0016] Figure 7 It is a schematic structural diagram of the position of the jet holes of the present invention.

[0017] Figure 8 It is a planar schematic diagram of the high lift-to-drag ratio airfoil structure after the hub of the present invention is unfolded.

[0018] In the figure: hub 1, groove 11, fillet 12, first type of blade 21, cambered airfoil structure 211, high lift-to-drag ratio airfoil structure 212, second type of blade 22, rim 3, protrusion 31, channel 4, air collecting chamber 5, jet hole 6, curved surface 7, pressure surface A, suction surface B. Specific embodiments

[0019] The following makes a detailed description of the present invention in conjunction with the accompanying drawings of the specification.

[0020] As Figures 1-8 shown, a high gas content spiral axial flow gas-liquid mixed transportation pump impeller includes a hub 1, blades and a rim 3. A plurality of arc-shaped grooves 11 are provided on the outer wall of the hub 1, and a plurality of arc-shaped protrusions 31 are provided on the inner wall of the rim 3. The centers of the grooves 11, the protrusions 31 and the hub 1 are located on the same straight line. Adjacent grooves 11 are connected by fillets 12. When the curvature radius of the groove 11 and the protrusion 31 is R1, the chord length is C, the depth is h, and the central angle is α1, the geometric relationship is satisfied: , and 0.13 < h / C < 0.17; α1 = 2arcsin(C / 2R1), and 45° < α1 < 65°, and the fillet radius R2 = (0.05 - 0.15)R1.

[0021] The blades include a first type of blade 21 and a second type of blade 22, which are arranged alternately in sequence. The number of the first type of blade 21 and the second type of blade 22 is the same, and each is at least two. The included angles of both the first type of blade 21 and the second type of blade 22 are greater than 120°, and the airfoil chord lengths of both types of blades are the same. The relative height in the radial direction is H, where H = 0 corresponds to the radius R3 of the outer wall of the hub, and H = 1 corresponds to the radius R4 of the inner wall of the wheel rim. Therefore, the value range of H is 0 ≤ H ≤ 1; when H ≤ 0.25 (such as Figure 4 and Figure 6 ), both the first type of blade 21 and the second type of blade 22 are reverse-curved airfoil structures 211 that are concave in the front and convex in the rear. A convex curved surface 7 is provided on the suction surface B at the end of the second type of blade 22. When H ≥ 0.5, both the first type of blade 21 and the second type of blade 22 are high-lift-drag-ratio airfoils 212 without reverse-curved features. When 0.25 < H < 0.5, the reverse-curved airfoil structure 211 of the first type of blade 21 and the second type of blade 22 smoothly transitions to the high-lift-drag-ratio airfoil structure 212.

[0022] A converging channel 4 is provided on the first type of blade 21. The inlet of the channel 4 opens on its pressure surface A, and the outlet opens on its suction surface B. In the flow direction, the inlet of the channel 4 is located at the maximum thickness of the convex curved surface 7. The included angle between the center line of the channel 4 and the tangent direction of the suction surface profile of the first type of blade 21 is α2 = 10° - 20°. The position of the center line of the channel 4 in the radial direction is 0.1 < H < 0.15. The inlet diameter of the channel 4 , where Q is the flow rate of the pump, ΔP is the pump boost value, ρ is the liquid phase density, the amplification coefficient k = 0.2 - 0.55, the split ratio β = 0.02 - 0.10, the flow coefficient C d = 0.6 - 0.75, and the outlet diameter D2 = (0.7 - 0.8)D1.

[0023] An air collection chamber 5 is provided on the hub on the suction surface side at the end of the first type of blade 21. A jet hole 6 is provided on the hub on the suction surface side in the middle of the second type of blade 22. The jet hole 6 in the hub 1 is connected to the air collection chamber 5; the air collection chamber 5 is elliptical on the developed surface of the hub 1, and the long axis direction of the air collection chamber 5 is consistent with the chord direction of the blade. The volume of the air collection chamber 5 , R3 is the radius of the hub, R4 is the radius of the inner wall of the wheel rim, L3 is the axial length of the impeller, Z is the number of blades, the gas retention coefficient k v = 0.05 - 0.15. The chord length distance from the leading edge of the air collection chamber 5 to the leading edge of the first type of blade 21 is L2 = (0.65 - 0.75)L1. The diameter D3 of the jet hole is (1.1 - 1.4)D1, where L1 is the chord length of the blade and D1 is the diameter of the inlet of the channel.

[0024] Its working principle is as follows: When the gas-liquid two-phase flow enters the impeller, the groove 11 on the hub 1 and the protrusion 31 on the inner wall of the rim 3 cause the conveyed gas-liquid medium to generate a curvature centrifugal force in the impeller. This force works in conjunction with the Coriolis force to weaken the driving force of the gas phase medium to migrate to the hub from the source, effectively suppressing gas-liquid separation and aggregation, thereby reducing the overall gas-liquid separation tendency and achieving the purpose of end wall suppression.

[0025] In the region where H ≤ 0.25, both type I blades 21 and type II blades 22 adopt a concave-convex airfoil structure 211, which can significantly slow down the trailing edge pressure recovery rate and reduce the tendency of gas stagnation. However, when H ≥ 0.5, both type I blades 21 and type II blades 22 adopt a high lift-to-drag ratio airfoil structure 212 without concave characteristics, so as to ensure overall work efficiency while suppressing gas phase adhesion.

[0026] Simultaneously, type I blades 21 and type II blades 22 are alternately arranged to construct a collaborative system of "active clearing and pressure stabilization." Type I blades 21, as high-load attack units, use a combination of a concave-convex recurved airfoil structure 211, jet holes, and gas collection chambers to actively break up, capture, and remove the gas phase accumulated on the suction surface B. Type II blades 22, as low-load pressure stabilization units, significantly reduce the risk of blockage due to their extremely low load. Through the convex curved surface 7 on their suction surface B, they enhance the guidance and energy replenishment of the jet on the working surface of adjacent type I blades 21. This results in a smoother pressure recovery in the concave area of ​​the pressure surface of type I blades 21, reducing gas phase retention near the trailing edge of type I blades 21.

[0027] At the tail of the suction surface of the first type of blade 21, the gas phase that accumulates due to the pressure gradient is guided into the gas collection chamber 5. This chamber is connected to the jet hole 6 through the interior of the hub 1, and the collected gas phase medium is directionally sprayed to the middle of the suction surface of the adjacent second type of blade 22. This jet replenishes the momentum of the suction surface of the second type of blade 22, enhances the fluid carrying capacity in this area, and thus actively reduces the degree of gas-liquid separation on the surface of the second type of blade 22 in this area.

[0028] Through the multi-level synergistic mechanism of "endwall suppression - airfoil guidance - cavity transfer - jet fragmentation" mentioned above, the gas phase in the impeller channel can be continuously managed and transported in an orderly manner, thereby significantly alleviating the intermittent gas blockage phenomenon and improving the continuity and stability of operation.

[0029] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. An impeller for a high gas content spiral axial flow gas-liquid mixing pump, comprising a hub, blades, and a rim, characterized in that: The radius of the outer wall of the hub is R3, and the radius of the inner wall of the rim is R4. A number of arc-shaped grooves are provided on the outer wall of the hub, and a number of arc-shaped protrusions are provided on the inner wall of the rim. The centers of the grooves, protrusions, and the hub are located on the same straight line. The adjacent two grooves are connected by fillets. The blades include type I blades and type II blades, and the type I blades and type II blades are arranged alternately in sequence. The number of type I blades and type II blades is the same, and each is at least two. The included angles of the type I blades and type II blades are both greater than 120°. The relative height in the radial direction is H, where H = 0 corresponds to the radius R3 of the outer wall of the hub, and H = 1 corresponds to the radius R4 of the inner wall of the rim. When H ≤ 0.25, both the type I blades and the type II blades are backward-curved airfoil structures with a concave front and a convex rear. A convex curved surface is provided on the suction surface at the end of the type II blades. When H ≥ 0.5, both the type I blades and the type II blades are high-lift-to-drag-ratio airfoils without backward-curved characteristics. When 0.25 < H < 0.5, the backward-curved airfoil structures of the type I blades and the type II blades are smoothly transitioned to high-lift-to-drag-ratio airfoil structures. A converging channel is provided on the type I blades. The inlet of the channel opens on its pressure surface, and the outlet opens on its suction surface. In the flow direction, the inlet of the channel is located at the maximum thickness of the curved surface protrusion. A gas collection cavity is provided on the hub on the suction surface side at the end of the type I blades. A jet hole is provided on the hub on the suction surface side in the middle of the type II blades. The jet hole in the hub is communicated with the gas collection cavity.

2. The impeller of a high gas content spiral axial flow gas-liquid mixing pump according to claim 1, characterized in that: When the curvature radii of the groove and the protrusion are R1, the chord length is C, the depth is h, and the central angle is α1, the following geometric relationships are satisfied: , and 0.13 < h / C < 0.17; α1 = 2arcsin(C / 2R1), and 45° < α1 < 65°, and the fillet radius R2 = (0.05 - 0.15)R1.

3. The impeller of a high gas content spiral axial flow gas-liquid mixing pump according to claim 1, characterized in that: The included angle between the center line of the said channel and the tangential direction of the suction surface profile of a certain type of blade is α2 = 10° - 20°, the radial position of the center line of the said channel is 0.1 < H < 0.15, and the inlet diameter of the said channel , where Q is the flow rate of the pump, ΔP is the pump boost value, ρ is the liquid phase density, the magnification factor k = 0.2 - 0.55, the split ratio β = 0.02 - 0.10, and the flow coefficient C d = 0.6 - 0.75, and the outlet diameter D2 = (0.7 - 0.8)D1.

4. The impeller of a high gas content spiral axial flow gas-liquid mixing pump according to claim 1, characterized in that: The air collection chamber is elliptical on the unfolded surface of the hub, and the major axis of the air collection chamber is aligned with the chord direction of the blades. The volume of the air collection chamber is... R3 is the hub radius, R4 is the radius of the inner wall of the impeller rim, L3 is the axial length of the impeller, Z is the number of blades, and k is the gas retention coefficient. v =0.05~0.15, the chord distance between the leading edge of the gas collecting cavity and the leading edge of the first type of blade is L2=(0.65~0.75)L1, and the diameter of the jet hole is D3=(1.1~1.4)D1, where L1 is the chord length of the blade and D1 is the diameter of the channel inlet.

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