Multiphase multiphase pump supercharging unit capable of inhibiting blade tip leakage flow

Abstract

The utility model provides a multiphase multiphase pump supercharging unit capable of restraining blade top leakage flow. The multiphase multiphase pump supercharging unit comprises an impeller and a guide blade. The impeller blades are arranged on the peripheral face of the impeller hub and spirally extend in the axial direction of the impeller hub, each impeller blade is provided with a first end and a second end in the extending direction, and each impeller blade is provided with an impeller hub side connected with the impeller hub and a rim side away from the impeller hub. A mounting angle is formed between the tangent line of the axial surface streamline of each impeller blade and the plane perpendicular to the axis of the impeller hub; and the starting ends of the impeller blades are uniformly distributed along the outer circumferential surface of the impeller hub. The number of the guide vane blades is eleven, and the starting ends of the guide vane blades are evenly distributed along the outer circumferential face of the guide vane hub. According to the utility model, the clearance leakage loss of the multiphase multiphase pump is reduced, the working efficiency of the multiphase multiphase pump is improved, and the hydraulic performance and the stability of the multiphase multiphase pump are further improved.

Description

Technical Field

[0001] The utility model belongs to the field of multiphase flow transportation, and specifically relates to a multiphase mixed flow pump booster unit capable of suppressing blade tip leakage flow, and is a spiral blade multiphase mixed flow pump widely used in oil and gas mixed transportation in oil and gas fields. Background Art

[0002] At present, multiphase mixed flow technology has gradually become a hot topic in domestic research. When the axial flow impeller machinery is running, in order to avoid friction and collision between the impeller blades and the end wall of the impeller chamber, there will be a certain distance of blade tip gap between the impeller and the pump body of the multiphase mixed flow pump. The leakage flow formed will be sucked together with the mainstream to form a gap leakage vortex, which will greatly affect the hydraulic performance of the mixed flow pump. Utility Model Content

[0003] The purpose of the utility model is to provide a multiphase mixed flow pump booster unit that can suppress the tip leakage flow, so that the influence of the tip leakage flow on the hydraulic performance of the mixed flow pump can be fundamentally improved by designing grooves on the tip of the blade, and the hydraulic performance and stability of the multiphase mixed flow pump can be further improved. It not only provides theoretical support for effectively suppressing the influence of the tip leakage vortex of the spiral axial flow multiphase mixed flow pump on the flow in its main flow channel, but also has important engineering practical value for improving the performance of the spiral axial flow multiphase mixed flow pump. At the same time, it also provides technical support for better application of the spiral axial flow multiphase mixed flow pump in engineering practice, and has the economic and social benefits of increasing the service life of the pump and reducing production costs.

[0004] The specific technical solutions are:

[0005] A multiphase mixed pump booster unit capable of suppressing blade tip leakage flow comprises an impeller and a guide vane; the impeller is located at an inlet section, and the guide vane is located at an outlet section;

[0006] The impeller includes an impeller hub and impeller blades; the impeller blades are arranged on the outer circumference of the impeller hub, and the impeller blades extend spirally along the axial direction of the impeller hub, the impeller blades have a first end and a second end in the extension direction, the impeller blades have an impeller hub side connected to the impeller hub and a rim side away from the impeller hub, and a placement angle is formed between the tangent of the axial streamline of the impeller blade and the plane perpendicular to the axis of the impeller hub. The impeller blades are arranged in three, and the starting ends of the three impeller blades are evenly arranged along the outer circumference of the impeller hub. The multiphase mixed pump booster unit capable of suppressing tip leakage flow, each impeller blade tip has the same groove.

[0007] The guide vane comprises a guide vane hub and guide vane blades; the guide vane blades are arranged in eleven numbers, and the starting ends of the eleven guide vane blades are evenly arranged along the outer circumferential surface of the guide vane hub.

[0008] There is a radial tip clearance between the impeller blades and the inner wall of the pump body.

[0009] The blade tops of the impeller blades are provided with grooves.

[0010] The utility model discloses a multiphase mixed pump booster unit which can suppress the blade tip leakage flow, introduces a structural modification method of blade tip grooves, designs a multiphase mixed pump booster unit with blade tip grooves, which has obvious effects on reducing the gap leakage loss of the multiphase mixed pump, improving the working efficiency of the multiphase mixed pump, and further improving the hydraulic performance and stability of the multiphase mixed pump. Practice has proved that the blade tip groove design can effectively improve the head and hydraulic efficiency of the mixed flow pump. The head and hydraulic efficiency of the mixed flow pump after the blade tip groove are increased by 8.15% and 1.4% respectively compared with the original model; (the influence of the blade tip leakage flow on the flow in the axial rear half of the impeller of the mixed flow pump is much greater than the influence on the flow in the axial front half of the impeller, especially the influence on the middle and rear position of the impeller flow channel is the greatest; the blade tip groove can inhibit the leakage flow from the pressure surface of the impeller blade to the suction surface in the opposite direction, and the gap leakage flow of the model with the blade tip groove is smaller than that of the original model. On each axial section of the blade tip in the rear half, the blade tip groove has a significant inhibitory effect on the leakage vortex, and the blade tip groove design will reduce the energy loss caused by flow in the main flow channel. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a structural schematic diagram of the utility model;

[0012] Figure 2 It is a schematic diagram of the blade tip groove of the impeller blade of the utility model;

[0013] Figure 3 It is the external characteristic curve of the mixed pump before and after the blade tip slots of the utility model. DETAILED DESCRIPTION

[0014] The specific technical solution of the utility model is explained in conjunction with the accompanying drawings.

[0015] like Figure 1 As shown, a multiphase mixed flow pump booster unit capable of suppressing blade tip leakage flow comprises an impeller 2 and a guide vane 3; the impeller 2 is located at the inlet section 1, and the guide vane 3 is located at the outlet section;

[0016] The impeller 2 comprises an impeller hub 21 and impeller blades 22; the impeller blades 22 are arranged on the outer circumferential surface of the impeller hub 21, and the impeller blades 22 extend spirally along the axial direction of the impeller hub 21, the impeller blades 22 have a first end and a second end in the extension direction, the impeller blades 22 have an impeller hub 21 side connected to the impeller hub 21 and a rim side away from the impeller hub 21, a placement angle is formed between the tangent of the axial streamline of the impeller blades 22 and the plane perpendicular to the axis of the impeller hub 21, the impeller blades 22 are set to three, and the starting ends of the three impeller blades 22 are evenly arranged along the outer circumferential surface of the impeller hub 21.

[0017] The guide vane 3 comprises a guide vane hub 31 and guide vane blades 32 ; the guide vane blades 32 are arranged in eleven numbers, and the starting ends of the eleven guide vane blades 32 are evenly arranged along the outer circumferential surface of the guide vane hub 31 .

[0018] Each blade top of the impeller blade 22 is provided with a same groove 23 .

[0019] There is a tip clearance between the impeller blades 22 and the inner wall of the pump body in the radial direction.

[0020] like Figure 2 As shown, the blade tip of the impeller blade 22 is provided with a groove 23 .

[0021] Table 1 Parameter settings

[0022]

[0023]

[0024] The specific parameter settings of this embodiment are shown in Table 1. The tip clearance is the radial clearance between the impeller blades 22 and the inner wall of the pump body. According to the manufacturing, installation and operation requirements, a certain tip clearance must be left. In this utility model, the tip clearance is set to 1mm. The design flow rate of the spiral axial flow multiphase mixed pump selected by this utility model is 90m 3 ·h -1 , the design speed is 3000r·min -1 The design impeller outer diameter is 161mm. The utility model is special in that the blade tip clearance is 1mm, initially set at a ratio of 1:1, and based on a single booster unit of a spiral axial flow multiphase mixed pump, the blade tips of the three blades 22 on the model are grooved with a groove depth of 1mm.

[0025] Compared with the blades of the conventional spiral axial flow multiphase mixed pump, the special feature of the present invention is that the blade tip clearance is 1 mm, and the blade tip clearance is set at a ratio of 1:1. Based on the single booster unit of the spiral axial flow multiphase mixed pump, the blade tips of the three blades on the model are adjusted as follows: Figure 2 The groove depth shown is 1 mm.

[0026] By modifying the impeller blade structure of the spiral axial flow multiphase mixed pump, the gap leakage loss of the multiphase mixed pump is reduced, thereby improving the working efficiency of the multiphase mixed pump.

[0027] Firstly, the external characteristics of the multiphase mixed pump before and after the modification were compared and analyzed. Figure 3 The head and hydraulic efficiency curves of the original model and the model with blade tip groove design at different flow rates. H1 and η1 represent the head and hydraulic efficiency of the original model, and H2 and η2 represent the head and hydraulic efficiency of the blade tip groove model. Figure 3 It can be seen that the head curve and hydraulic efficiency curve before and after the blade top slot have the same change trend. The head decreases with the increase of flow rate, and the efficiency increases first and then decreases with the increase of flow rate. 3 The flow condition is the optimal efficiency point. It can also be seen that the head curve and hydraulic efficiency curve after the blade top is slotted are higher than the head curve and hydraulic efficiency curve of the original model. 3 At the flow rate of / h, the head of the original model is 9.08m, and the head of the blade tip groove model is 9.82m. The head is increased by 8.15% after the blade tip groove is designed; the hydraulic efficiency of the original model is 46.64%, and the hydraulic efficiency of the blade tip groove model is 48.04%. The hydraulic efficiency is increased by 1.4% after the blade tip groove is designed. This shows that the blade tip groove design can effectively improve the head and hydraulic efficiency of the multiphase mixed pump and improve its hydraulic performance.

[0028] Secondly, the flow characteristics of the blade tip leakage flow of the multiphase mixed pump before and after optimization are compared and analyzed:

[0029] (1) By setting points on the intersection of the extended surface of the blade suction surface and the middle surface of the blade tip gap, where the monitoring points are divided into 50 equal parts by the arc length of the intersection, all monitoring points are used to monitor the axial component of the incoming flow velocity. The axial velocity at the monitoring point is equal to the sum of the mainstream axial velocity (the same direction as the mainstream flow, the value is positive) and the leakage flow axial velocity (opposite to the mainstream flow direction, the value is negative). The results obtained by numerical calculation are plotted into a curve with the relative arc length as the horizontal axis and the gap flow axial velocity as the vertical axis to analyze the influence of the blade tip groove on the leakage flow velocity distribution law. It is concluded that the influence of the blade tip leakage flow on the flow in the axial rear half of the mixed flow pump impeller is much greater than the influence on the flow in the axial front half of the impeller, especially the influence on the middle and rear position of the impeller flow channel is the greatest.

[0030] (2) Divide the suction side of the blade tip clearance into 25 equal parts according to the arc length. The calculation formula is: (where ρ is the density of the fluid, V represents the average velocity of the fluid when it flows through each section, and ΔA is the cross-sectional area), calculate the leakage flow value on each equally divided section And according to the inlet flow The dimensionless distribution curve of the gap leakage flow along the blade tip is obtained according to the calculation results, and the influence of the blade tip groove on the gap leakage flow is analyzed through the curve. It is found that when the blade tip gap flow is in the same direction as the mainstream flow, the axial velocity of the model with the blade tip groove at the same monitoring point is greater than the axial velocity of the gap flow of the original model; when the blade tip gap flow is in the opposite direction to the mainstream flow, the axial velocity of almost all monitoring points on the blade tip groove model is less than the axial velocity of the gap flow of the original model, indicating that the blade tip groove plays a role in inhibiting the leakage flow from the pressure surface of the impeller blade to the suction surface.

[0031] (3) A complete blade is selected and divided into ten equal parts at 20° from the leading edge to the trailing edge, thus obtaining 11 axial sections. By observing the streamline distribution in the gap at different sections, it can be seen that obvious vortices are formed in the blade tip groove, and these vortices develop and change in the groove, and then study how the groove affects the flow of the blade tip gap leakage. It is found that at the leading edge of the impeller blade, the leakage flow at the blade tip gap of the original model and the blade groove model is negative, indicating that there is no gap leakage flow at this position, that is, the flow direction of the fluid at the blade leading edge gap is the same as the mainstream flow direction; with the increase of the relative arc length, the gap leakage flow appears, and the leakage flow flow increases first and then decreases, and the leakage flow reaches the maximum at the relative arc length of 0.6; from the leading edge to the trailing edge of the blade, the gap leakage flow of the blade tip groove model is smaller than that of the original model. At the relative arc length of 0.2-0.4, the groove has the most obvious effect on the suppression of leakage flow.

[0032] (4) According to the theory of axial flow pump blade tip leakage vortex structure, the velocity vector diagram of the axial section of the impeller section of the multiphase mixed flow pump can be divided into four regions: leakage jet zone, leakage shear zone, axial mainstream zone and leakage vortex core zone. The area close to the pump casing end wall is defined as the leakage jet zone, and its velocity vector direction is opposite to the axial mainstream direction. The shear vortex zone below it formed by the interaction between the jet and the axial mainstream is defined as the leakage shear zone. The vortex formed by the shear zone is transported to the leakage vortex core zone with the leakage flow. The area with smooth flow at the bottom is defined as the axial mainstream zone. The three-dimensional vortex structure in the two impellers identified by the Q criterion is directly analyzed to analyze the influence of the blade tip groove on the blade tip leakage vortex. Then, by observing the vortex cloud diagrams on different axial sections of the two models of the original model impeller and the blade tip groove model impeller, the change of the blade tip leakage vortex intensity can be more clearly understood. It is found that the leakage vortex intensity of the blade tip groove model is significantly lower than that of the original model on each axial section of the rear half of the blade tip, indicating that the blade tip groove has an inhibitory effect on the leakage vortex in this area.

[0033] Finally, a comparative analysis of the energy dissipation characteristics in the flow channel of the multiphase mixed flow pump before and after optimization was conducted. According to the second law of thermodynamics, entropy generation is a parameter that characterizes the mechanical energy dissipation caused by irreversible factors during energy conversion. The entropy generation theory is linked to the mechanical energy dissipation during the flow process in hydraulic machinery to find out the location and magnitude of mechanical energy dissipation. It is found that the entropy generation generated in the area near the rim of the blade tip groove model is significantly smaller than the entropy generation in the area near the rim of the original model. The blade tip groove design will reduce the energy loss caused by flow in the main flow channel, but the blade tip groove design has little effect on the entropy generation of the blade surface and will not affect the work performance of the blade.

[0034] Through the analysis of the above experimental results, it can be known that the multiphase mixed pump booster unit capable of suppressing blade tip leakage flow of the utility model can effectively suppress the influence of blade tip leakage flow on the flow in the main flow channel, thereby improving the hydraulic performance of the pump.

Claims

1. A multiphase mixed flow pump booster unit capable of suppressing blade tip leakage flow, characterized in that: It comprises an impeller (2) and a guide vane (3); the impeller (2) is located at the inlet section (1), and the guide vane (3) is located at the outlet section; The impeller (2) comprises an impeller hub (21) and impeller blades (22); the impeller blades (22) are arranged in three numbers, and the starting ends of the three impeller blades (22) are evenly arranged along the outer circumferential surface of the impeller hub (21).

2. A multiphase mixed flow pump booster unit capable of suppressing blade tip leakage flow according to claim 1, characterized in that: A blade tip clearance is left between the impeller blades (22) and the inner wall of the pump body in the radial direction.

3. A multiphase mixed flow pump booster unit capable of suppressing blade tip leakage flow according to claim 1, characterized in that: Each blade top of the impeller blade (22) is provided with an identical groove (23).

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