Inducing wheel and blade reshaping method

Abstract

The application relates to an inducer wheel and a blade profiling method. The inducer wheel comprises a wheel shaft and a blade, the blade is arranged on the wheel shaft, and the blade is helical and rotates along a helical reference track line. Two side surfaces of the blade are a working surface and a non-working surface respectively, the non-working surface is provided with a guide flow area and a flow area, the guide flow area has an initial area line and an end area line; a plurality of flow track line segments are arranged between the initial area line and the end area line, the flow track line segments extend along the helical reference track line, the starting point of each flow track line segment is located on the initial area line, and the end point of each flow track line segment is located on the end area line. Along the height direction of the blade, the height direction of the blade is perpendicular to the helical reference track line, and the lengths of the plurality of flow track line segments gradually increase. The inducer wheel according to the application has high cavitation resistance, has lower flow resistance on the inlet side of the inducer wheel, and has high performance.

Description

Technical Field

[0001] This application relates to the field of fluid machinery technology, and in particular to an inducer and a method for modifying the blades of the inducer. Background Technology

[0002] An inducer is an impeller used in centrifugal pumps. Installed at the front end of the centrifugal impeller, it increases the inlet pressure of the centrifugal pump, thereby improving the pump's resistance to cavitation. The blades of the inducer are helical and evenly arranged along its circumference. When the inducer rotates, it transports liquid along its axial direction from one side to the other. That is, along the axial direction of the inducer, one side has an inlet, and the other side has an outlet. This can be understood as the liquid flowing from the inlet to the outlet side along the axial direction of the inducer as it rotates.

[0003] In related technologies, the inducer has low anti-cavitation capability, which leads to cavitation during operation and weakens the boosting performance of the inducer. Summary of the Invention

[0004] Therefore, it is necessary to provide an induced wheel to address the problem of low cavitation resistance.

[0005] An inducer wheel includes:

[0006] axle;

[0007] The blades are mounted on the wheel axle and are helical in shape, rotating along the helical reference trajectory line. The two sides of the blades are the working surface and the non-working surface, respectively. The non-working surface is provided with a guide area and a flow area. The guide area has an initial area line and an end area line.

[0008] There are several flow trajectory segments between the initial region line and the final region line. The flow trajectory segments extend along the helical reference trajectory line. The starting point of each flow trajectory segment is located at the initial region line, and the ending point of each flow trajectory segment is located at the final region line. Along the height direction of the blade, which is perpendicular to the helical reference trajectory line, the length of several flow trajectory segments gradually increases.

[0009] In one embodiment, the leading edge of the blade has an initial edge, and the initial region line is the line formed by the initial edge.

[0010] In one embodiment, the flow guiding region includes a flow guiding surface and a transition surface, the transition surface connecting the flow guiding surface and the flow region, and the slope of the flow guiding surface is K1, satisfying the relationship: 0.2≤K1≤0.5.

[0011] The aforementioned inducer impeller, because the flow trajectory segments of the blades extend along the helical reference trajectory line, and the length of several flow trajectory segments gradually increases along the height direction of the blades, ensures that during the process of liquid flowing from the guide region to the flow region relative to the blades, liquid at the initial region line at the same moment can simultaneously reach the final region line. This can also be understood as liquid flowing along the guide region at the same moment flowing into the flow region simultaneously, ensuring consistent liquid flow, avoiding cavitation, improving the inducer impeller's anti-cavitation capability, increasing the effective thrust area of ​​the inducer impeller, and reducing its drag. Therefore, the inducer impeller manufactured according to this application has high anti-cavitation capability, lower flow resistance on the inlet side, lower internal turbulence, and high overall performance.

[0012] This application further proposes a blade modification method based on the inducer in some of the above embodiments, the blade modification method including the following steps:

[0013] Determine the flow guiding areas in some of the above embodiments in the non-working surface;

[0014] The steps for determining the diversion area include,

[0015] Construct the axial orthographic projection plane of the inducer wheel, which has an initial region projection line in the axial orthographic projection plane;

[0016] Multiple concentric circles are constructed in the axial orthographic projection plane. The center of each concentric circle coincides with the axis of the inducer wheel. The intersection of the concentric circle and the initial region projection line is the starting reference point. The initial region projection line is the projection of the initial region line in the axial orthographic projection plane, and the starting reference point is the projection of the starting point in the axial orthographic projection plane.

[0017] Construct a connecting radial line in the axial orthographic projection plane, connecting the center of the starting reference point and its corresponding concentric circle;

[0018] Select the rotation angle θ;

[0019] In the circumferential direction of the axial orthographic projection plane, connecting radial lines are rotated by an angle θ in a direction away from the initial region projection line to construct the corresponding deflection radial lines. The intersection of the deflection radial lines and the corresponding concentric circles is the termination reference point, which is the projection of the termination point onto the axial orthographic projection plane. Multiple termination reference points are connected sequentially to form the endpoint region projection line, where adjacent termination reference points are connected by a smooth curve segment. The endpoint region projection line is the projection of the endpoint region line onto the axial orthographic projection plane. A flow trajectory projection line segment is connected between the initial reference point and the termination reference point in the same concentric circle. The curvature of the flow trajectory projection line segment is equal to the curvature of the concentric circle, and the flow trajectory projection line segment is the projection of the flow trajectory line segment onto the axial orthographic projection plane.

[0020] The initial region projection line and the final region projection line together constitute the guide region projection surface, which is the projection of the guide region onto the axial orthogonal projection surface.

[0021] Polish the flow guide area;

[0022] Inspect the diversion area.

[0023] In one embodiment, in the step of selecting the rotation angle θ, the length L1 of the projected line segment of the flow trajectory and the diameter D of the corresponding concentric circle are determined, satisfying the relationship: θ=L1 / D.

[0024] In one embodiment, the step of determining the guiding region further includes marking the guiding region, the step of marking the guiding region including,

[0025] The flow guiding area projection surface is printed in the first cover, and the first cover is attached to the non-working surface;

[0026] Remove a portion of the projected surface of the indicated flow-guiding area from the first cover;

[0027] Alternatively, a marking tool can be used to mark along the edge of the projection surface of the guide area.

[0028] In one embodiment, the step of determining the guiding region further includes marking the guiding region, the step of marking the guiding region including,

[0029] Project the image with the projection surface of the flow guide area onto the non-working surface;

[0030] The guide area is illustrated by the projection surface of the guide area onto the non-working surface;

[0031] Alternatively, a marking tool can be used to mark along the edge of the projection surface of the guide area.

[0032] In one embodiment, during the step of inspecting the flow guidance area...

[0033] Mark the flow trajectory line segments;

[0034] Select at least two measurement points within the flow trajectory segment;

[0035] Measure the thickness value H2 at each measurement point, and measure the distance L2 between the measurement point and the starting point in the same flow trajectory segment;

[0036] Compare the slope values ​​K2 at multiple measurement points, and the relationship is satisfied: K2=L2 / H2.

[0037] In one embodiment, in the step of marking the flow trajectory segment...

[0038] A strip-shaped through hole is provided in the second cover to indicate the projection line segment of the flow trajectory, so that the second cover is attached to the non-working surface;

[0039] The strip-shaped through-hole section is used to illustrate the flow trajectory line segment.

[0040] In one embodiment, in the step of marking the flow trajectory segment...

[0041] Project the image with the flow trajectory projection line segments onto the non-working surface;

[0042] The flow trajectory line segment is shown by the projection line segment of the flow trajectory onto the non-working surface. Attached Figure Description

[0043] Figure 1 This is a perspective view of the guide wheel according to an embodiment of this application.

[0044] Figure 2 This is a front view of an inducer wheel according to an embodiment of this application.

[0045] Figure 3 This is a top view of an inducer wheel according to an embodiment of this application.

[0046] Figure 4 for Figure 3 Cross-sectional view at point AA.

[0047] Figure 5 This is a flowchart of a blade modification method according to an embodiment of this application.

[0048] Figure 6 This is a schematic diagram of the axial orthographic projection of an inducer wheel according to an embodiment of this application.

[0049] Figure Labels

[0050] 100. Inducer wheel;

[0051] 1. Wheel and axle;

[0052] 2. Blade; 21. Working surface; 22. Non-working surface; 22a. Guide zone; 22b. Flow zone;

[0053] 23. Outer edge; 23a. Leading edge; 23b. Trailing edge;

[0054] 10. Spiral reference trajectory line;

[0055] 11a. Initial region line; 11b. Ending region line;

[0056] 12. Flow trajectory line segment; 12a. Starting point; 12b. Ending point;

[0057] 13a. Initial region projection lines; 13b. Ending region projection lines;

[0058] 14. Projected line segment of the flow trajectory; 14a. Starting reference point; 14b. Ending reference point;

[0059] 15a. Connecting radial lines; 15b. Deflecting radial lines;

[0060] 16. Measurement points. Detailed Implementation

[0061] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0062] In the description of this application, it should be understood that if terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0063] Furthermore, where the terms "first" and "second" appear, these terms are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, where the term "multiple" appears, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0064] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0065] In this application, unless otherwise expressly specified and limited, the use of descriptions such as "above" or "below" the second feature indicates that the first and second features are in direct contact or indirect contact via an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. Similarly, "below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0066] It should be noted that if an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. If an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. If so, the terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application are for illustrative purposes only and do not represent the only possible implementation.

[0067] See Figures 1 to 4 As shown, according to some embodiments of this application, the inducer wheel 100 includes a wheel axle 1 and blades 2, the number of blades 2 being configured to be at least two. For example, see [reference needed]. Figures 2 to 4 As shown, in one embodiment of this application, the number of inducer wheels 100 is configured to be three. Blades 2 are disposed on the axle 1, combined with... Figure 1 As shown, the blade 2 is connected to the outer peripheral surface of the axle 1. It should be noted that in some embodiments, the blade 2 and the axle 1 are integrally formed, thereby ensuring the connection strength between the blade 2 and the axle 1. A helical reference trajectory line 10 is provided in the circumferential direction of the axle 1. The helical reference trajectory line 10 extends along the axial and circumferential directions of the axle 1, so that the helical reference trajectory line 10 forms a helix on the outer peripheral surface of the axle 1. The blade 2 is a helix rotating along the helical reference trajectory line 10.

[0068] Along the axial direction of the inducer 100 (i.e., the axial direction of the axle 1), the two side surfaces of the blade 2 are the working surface 21 and the non-working surface 22, respectively. Figures 3 to 5As shown, the non-working surface 22 is provided with a guide region 22a and a flow region 22b. The guide region 22a has an initial region line 11a and an end region line 11b. There are several flow trajectory segments 12 between the initial region line 11a and the end region line 11b. The flow trajectory segments 12 extend along the helical reference trajectory line 10. It can also be understood that in the radial direction of the inducer wheel 100, the flow trajectory segments 12 are parallel to the helical reference trajectory line 10. The starting point 12a of each flow trajectory segment 12 is located at the initial region line 11a, and the ending point 12b of each flow trajectory segment 12 is located at the end region line 11b. Along the height direction of the blade 2, which is perpendicular to the helical reference trajectory line 10, the length of the several flow trajectory segments 12 gradually increases.

[0069] For example, see Figure 1 As shown in one embodiment of this application, three flow trajectory segments 12 are provided in each blade 2 as an example for illustration. However, this application is not limited to this, and the number of flow trajectory segments 12 provided in each blade 2 can be configured to be five, ten, or even countless. It should also be noted that the aforementioned flow trajectory segments 12 can be virtual segments, which can be understood as flow trajectory segments 12 not appearing on the surface of the blade 2.

[0070] For example, see Figure 1 and Figure 2 As shown, the blade 2 has an inner edge and an outer edge 23. The inner edge of the blade 2 is connected to the outer peripheral surface of the wheel shaft 1, and the inner edge of the blade 2 extends along the helical reference trajectory line 10. Along the extension direction of the blade 2, the outer edge 23 of the blade 2 includes a leading edge 23a and a trailing edge 23b. The leading edge 23a of the blade 2 is the inlet side portion, and the trailing edge 23b of the blade 2 is the portion near the outlet side. The leading edge 23a and the trailing edge 23b are connected to form the outer edge 23 of the blade 2.

[0071] Combination Figures 1 to 3 As shown, during operation, the inducer 100 rotates axially around its axis. For details, please refer to [reference needed]. Figure 3 As shown, during operation, the inducer 100 rotates clockwise, and the leading edge 23a of the blade 2 moves relative to the liquid to cut the liquid, thereby guiding the liquid to flow along the axial direction of the inducer 100 from the inlet side to the outlet side. In one embodiment, the initial region line 11a is selected to coincide with the leading edge 23a of the blade 2. During the process of the liquid flowing along the non-working surface 22 from the inlet side to the outlet side, the liquid sequentially passes through the guiding region 22a and the flow region 22b, so that the liquid flows along the axial direction of the inducer 100 from the inlet side to the outlet side.

[0072] See Figures 1 to 3 As shown, during the operation of the inducer wheel 100, when the rotational speed of the inducer wheel 100 is constant, the number of revolutions per second of the inducer wheel 100 as a whole is fixed. However, in the radial direction of the inducer wheel 100 (i.e., from the inner edge of the blade 2 to the outer edge 23 of the blade 2), as the distance between the inner edge and the outer edge 23 of the blade 2 gradually increases, the tangential velocity of the point on the outer edge 23 of the blade 2 also increases accordingly. This is because the tangential velocity (i.e., linear velocity) is the product of the rotational speed and the radius; therefore, as the radius increases, the tangential velocity of the point on the outer edge 23 of the blade 2 also increases accordingly. Thus, during the rotation and cutting of the liquid by the inducer wheel 100, the relative velocity between the liquid and the blade 2 is greater in the radial direction of the inducer wheel 100.

[0073] For the reasons mentioned above, in the inducer 100 according to this application, since the flow trajectory segment 12 of the blade 2 extends along the helical reference trajectory line 10, and along the width direction of the blade 2 (i.e., from the inner edge of the blade 2 to the outer edge 23 of the blade 2), the length of several flow trajectory segments 12 gradually increases. Therefore, during the process of liquid flowing from the guide region 22a to the flow region 22b relative to the blade 2, the liquid micro-element at the initial region line 11a at the same time can approach and simultaneously reach the endpoint region line 11b. It can also be understood that the liquid flowing along the guide region 22a at the same time can flow into the flow region 22b at the same time, ensuring that the ratio of the flow field velocity entering the flow region 22b to the diameter at the location is consistent, and no shear occurs in the blade height direction, avoiding eddies and turbulent disturbances, thereby reducing cavitation phenomena, improving the anti-cavitation capability of the inducer 100, and reducing the resistance of the inducer 100, thus improving the performance of the inducer 100.

[0074] It's important to explain that cavitation is a specific physical phenomenon occurring in liquid media, involving the generation, development, and collapse of air bubbles. Cavitation generation is a dynamic process, typically accompanied by drastic pressure changes. In the first stage of cavitation, the cavitation region is localized, forming in low-pressure areas and collapsing upon entering high-pressure areas. In the second stage, cavitation may form a large cavity on the upper surface of objects such as hydrofoils or propellers, collapsing behind the object. In the third stage, the cavity may cover the entire surface of the object, leading to a deterioration in its hydrodynamic performance. Cavitation has significant impacts on many engineering fields. In marine engineering, cavitation can cause propeller surface corrosion, increasing drag and reducing efficiency. In hydrofoil design, cavitation can worsen the hydrodynamic performance of the hydrofoil and even cause hull vibration and noise problems. Furthermore, the shock waves and microjets generated during cavitation collapse can cause erosion damage to metal surfaces, a phenomenon known as cavitation corrosion or cavitation erosion. Cavitation corrosion mainly occurs when high-speed fluids flow over complex-shaped metal surfaces, such as turbine blades and pump impellers. When a blunt object cuts a liquid at high speed, it can easily cause a sudden drop in local pressure at the shear point, triggering liquid vaporization; at the same time, it can also create vortices and turbulence, causing the diffusion of cavitation bubbles, which in turn affects the flow field over a large area.

[0075] See Figure 3 As shown, in some embodiments of this application, the leading edge 23a of the blade 2 has an initial edge, and the initial region line 11a is the line formed by the initial edge. Since the leading edge 23a is the part of the blade 2 that begins to contact the liquid, by setting the initial edge at the leading edge 23a of the blade 2 and reducing the thickness of the blade at the leading edge 23a, the occurrence of cavitation can be reduced more effectively.

[0076] See Figure 3 and Figure 4 As shown, in some embodiments of this application, the guiding region 22a includes a guiding surface and a transition surface. The transition surface connects the guiding surface and the flow region 22b. The slope of the guiding surface is K1, satisfying the relationship: 0.2≤K1≤0.5. When the inducer wheel 100 is rotating, during the movement of the liquid relative to the blade 2, the liquid moves along the guiding surface to the transition surface and then flows towards the flow region 22b. Due to the angle of the guiding surface, the thickness of the guiding surface in the blade 2 gradually increases. This reduces the resistance of the blade 2 and decreases the bluntness of the inlet edge during the cutting process of the blade 2, while ensuring the thickness of the blade 2. This allows the turbulence transition position to move closer to the inlet side, reducing the length of the transition zone and improving the stability of the flow field in the flow region, thus enhancing the performance of the inducer wheel 100. It should be further noted that, in conjunction with... Figure 3 and Figure 4 As shown, K1 = L / H, where L is Figure 3The arc length within the guide surface in the middle AA, and H is the thickness of this region. Therefore, the inclination angle of the guide surface at different positions in the radial direction of the inducer 100 is also different.

[0077] It should be noted that the transition surface is a smooth transition between the guide surface and the flow region 22b, avoiding the formation of an edge in the endpoint region line 11b. If the endpoint region line 11b is an edge, the liquid will undergo flow separation (i.e., detachment from the wall) as it flows through the endpoint region line 11b, generating separation vortices. The vortices near the wall will shear the outer streamlines, causing local turbulence and reducing the efficiency of the inducer 100. Therefore, according to some embodiments of this application, the inducer 100, by providing a smooth transition surface between the guide surface and the flow region 22b, can suppress the intensity of flow separation or increase the critical velocity at which flow separation occurs, thereby avoiding local turbulence and ensuring the efficiency of the inducer 100.

[0078] See Figure 5 As shown, the blade modification method for the inducer in some of the above embodiments includes the following steps:

[0079] S1. Determine the flow guiding area in some of the above embodiments in the non-working surface.

[0080] S2, Grind the flow guide area.

[0081] S3, Inspect the flow guidance area.

[0082] Step S1 includes:

[0083] S11. Construct the axial orthographic projection plane of the inducer wheel, which has an initial region projection line.

[0084] S12. Construct multiple concentric circles in the axial orthographic projection plane. The center of each concentric circle coincides with the axis of the inducer wheel. The intersection of the concentric circle and the initial region projection line is the starting reference point. The initial region projection line is the projection of the initial region line onto the axial orthographic projection plane, and the starting reference point is the projection of the starting point onto the axial orthographic projection plane.

[0085] S13. Construct a connecting radial line in the axial orthographic projection plane, connecting the starting reference point to the center of its corresponding concentric circle.

[0086] S14. Select the rotation angle θ.

[0087] S15. In the circumferential direction of the axial orthographic projection plane, the connecting radial line is rotated by a rotation angle θ in a direction away from the initial region projection line to construct the corresponding deflection radial line. The intersection of the deflection radial line and the corresponding concentric circle is the termination reference point, which is the projection of the termination point on the axial orthographic projection plane.

[0088] S16. Connect multiple termination reference points in sequence to form the endpoint region projection line, wherein two adjacent termination reference points are connected by a smooth curve segment, and the endpoint region projection line is the projection of the endpoint region line onto the axial orthogonal projection plane.

[0089] S17. Connect the starting reference point and the ending reference point in the same concentric circle to form a flow trajectory projection line segment. The curvature of the flow trajectory projection line segment is equal to the curvature of the concentric circle, and the flow trajectory projection line segment is the projection of the flow trajectory line segment onto the axial orthogonal projection plane.

[0090] S18. The initial region projection line and the final region projection line together form the guide region projection surface, which is the projection of the guide region onto the axial orthogonal projection surface.

[0091] According to the blade shaping method in some embodiments of this application, the inducer 100 in the above embodiments can be manufactured. The inducer 100 according to this application can avoid cavitation, improve the anti-cavitation capability of the inducer 100, increase the effective thrust area of ​​the inducer 100, and reduce the resistance of the inducer 100, thereby improving the performance of the inducer 100.

[0092] For example, see Figure 6 As shown, Figure 6 This is the axial orthographic projection plane of the inducer wheel 100 according to an embodiment of this application, and it has an initial region projection line 13a in the axial orthographic projection plane. Furthermore, a plurality of concentric circles are constructed in the axial orthographic projection plane, see reference [link to relevant documentation]. Figure 6 As shown, in one embodiment of this application, three concentric circles are constructed in the axial orthographic projection plane as an example. The center of each concentric circle coincides with the axis of the inducer wheel 100, and the intersection of the concentric circles with the initial region projection line 13a is the starting reference point 14a. That is, each initial region projection line 13a has three starting reference points 14a. It should be noted that the initial region projection line 13a is the projection of the initial region line 11a in the axial orthographic projection plane, and the starting reference point 14a is the projection of the starting point 12a in the axial orthographic projection plane.

[0093] Then, a connecting radial line 15a is constructed in the axial orthographic projection plane, connecting the starting reference point 14a to the center of its corresponding concentric circle. Next, a rotation angle θ is selected, and in the circumferential direction of the axial orthographic projection plane, the connecting radial line 15a is rotated by the rotation angle θ in a direction away from the initial region projection line 13a to construct the corresponding deflection radial line 15b. The intersection of the deflection radial line 15b and the corresponding concentric circle is the termination reference point 14b. It should be noted that the termination reference point 14b is the projection of the termination point 12b onto the axial orthographic projection plane.

[0094] Furthermore, a flow trajectory projection line segment 14 connects the starting reference point 14a and the ending reference point 14b within the same concentric circle. It should be noted that the curvature of the flow trajectory projection line segment 14 is equal to the curvature of the concentric circle, and the flow trajectory projection line segment 14 is the projection of the flow trajectory line segment 12 onto the axial orthographic projection plane. The initial region projection line 13a and the ending region projection line 13b together constitute the guide region projection plane, which is the projection of the guide region 22a onto the axial orthographic projection plane.

[0095] It should be noted that, in the above embodiment, the example of constructing three concentric circles in the axial orthographic projection plane is used for illustration, but this application is not limited to this. The number of concentric circles constructed in the axial orthographic projection plane is at least two, and the number of concentric circles can be configured to be ten, twenty, fifty, or even countless.

[0096] In some embodiments of this application, combined with Figure 6 As shown, in the step of selecting the rotation angle θ, the length L1 of the projected line segment 14 of the flow trajectory and the diameter D of the corresponding concentric circle are determined, satisfying the relationship: θ=L1 / D.

[0097] In some embodiments of this application, combined with Figure 3 As shown, the step of determining the flow guiding region 22a further includes marking the flow guiding region 22a. This step involves printing a projection surface of the flow guiding region on the first cover, attaching the first cover to the non-working surface 22, and then removing the portion of the first cover indicating the projection surface of the flow guiding region. Alternatively, a marking tool can be used to mark along the edge of the projection surface of the flow guiding region, thereby marking a portion of the flow guiding region 22a on the non-working surface 22. This facilitates the operator's polishing of the non-working surface 22 to form the flow guiding region 22a. For example, the first cover can be a transparent film.

[0098] In other embodiments of this application, combined with Figure 3 As shown, the step of marking the guide region 22a includes projecting an image of the guide region projection surface onto the non-working surface 22. The guide region 22a is illustrated by the projection surface of the guide region onto the non-working surface 22, or a marking tool is used to mark along the edge of the guide region projection surface. This marks a portion of the guide region 22a on the non-working surface 22, facilitating the operator's grinding of the non-working surface 22 to form the guide region 22a. For example, laser projection can be used to project the image of the guide region projection surface onto the non-working surface 22, and the marking tool can be a pen, a carving knife, or other tool capable of marking on the non-working surface 22.

[0099] In some embodiments of this application, combined with Figure 3As shown, the steps for inspecting the flow guiding region 22a include: first, marking the flow trajectory segment 12; then, selecting at least two measurement points 16 within the flow trajectory segment 12 and measuring the thickness value H2 at each measurement point 16; measuring the distance L2 between the measurement point 16 and the starting point 12a within the same flow trajectory segment 12; and comparing the slope values ​​K2 of multiple measurement points 16, where the relationship is satisfied: K2 = L2 / H2. If the slope value K2 of each measurement point 16 is the same, it indicates that the flow guiding region 22a is a smooth surface. Preferably, after inspection, K2 = K1.

[0100] In some embodiments of this application, combined with Figure 3 As shown, in the step of marking the flow trajectory segment 12, a strip-shaped through-hole indicating the projected flow trajectory segment 14 is provided in the second cover. The second cover is attached to the non-working surface 22 so that the strip-shaped through-hole portion is used to indicate the flow trajectory segment 12, thereby marking the flow trajectory segment 12 in the non-working surface 22, so that the operator can select the measurement point 16 in the flow trajectory segment 12 in the guide area 22a. For example, the second cover can be a transparent film.

[0101] In other embodiments of this application, combined with Figure 3 As shown, in the step of marking the flow trajectory segment 12, an image with the flow trajectory projection segment 14 drawn on it is projected onto the non-working surface 22. The flow trajectory projection segment 14 projected onto the non-working surface 22 indicates the flow trajectory segment 12, thereby marking the flow trajectory segment 12 in the non-working surface 22. This facilitates the operator in selecting the measurement point 16 within the flow trajectory segment 12 in the guide area 22a. For example, a laser projection method can be used to project an image of the guide area projection surface onto the guide area 22a, and the marking tool can be a pen or other tool capable of marking in the guide area 22a.

[0102] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0103] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for modifying the blades of an inducer, characterized in that, The inducer wheel includes: a wheel shaft and blades, the blades being disposed on the wheel shaft, and the blades being helical in shape rotating along a helical reference trajectory line; the two sides of the blades are respectively a working surface and a non-working surface, and the non-working surface is provided with a guide area and a flow area; The guiding region has an initial region line and an ending region line. Between the initial region line and the ending region line are several flow trajectory segments. These flow trajectory segments extend along the spiral reference trajectory line. The starting point of each flow trajectory segment is located at the initial region line, and the ending point of each flow trajectory segment is located at the ending region line. Along the width direction of the blade, the length of several flow trajectory segments gradually increases. The flow guiding region includes a flow guiding surface and a transition surface. The transition surface connects the flow guiding surface and the flow region. The slope of the flow guiding surface is K1, satisfying the relationship: 0.2≤K1≤0.5, where K1=L / H, L is the arc length of a certain flow trajectory segment within the flow guiding surface; H is the maximum thickness of the flow trajectory segment within the blade. The method includes the following steps: The flow guiding region is defined in the non-working surface; The step of determining the flow guidance area includes, Construct the axial orthographic projection plane of the inducer wheel, in which an initial region projection line is formed; Multiple concentric circles are constructed in the axial orthographic projection plane, and the center of each concentric circle coincides with the axis of the inducer wheel. The intersection of the concentric circle and the initial region projection line is the starting reference point. The initial region projection line is the projection of the initial region line in the axial orthographic projection plane, and the starting reference point is the projection of the starting point in the axial orthographic projection plane. A connecting radial line is constructed in the axial orthographic projection plane, the connecting radial line connecting the center of the concentric circle corresponding to the starting reference point; Select the rotation angle θ; In the circumferential direction of the axial orthographic projection plane, the connecting radial line rotates at the rotation angle θ in a direction away from the initial region projection line to construct a corresponding deflection radial line. The intersection of the deflection radial line and the corresponding concentric circle is the termination reference point, which is the projection of the termination point onto the axial orthographic projection plane. Multiple termination reference points are connected sequentially to form the endpoint region projection line, wherein adjacent termination reference points are connected by a smooth curve segment, and the endpoint region projection line is the projection of the endpoint region line onto the axial orthographic projection plane. A flow trajectory projection line segment is connected between the starting reference point and the termination reference point in the same concentric circle. The curvature of the flow trajectory projection line segment is equal to the curvature of the concentric circle, and the flow trajectory projection line segment is the projection of the flow trajectory line segment onto the axial orthographic projection plane. The initial region projection line and the final region projection line together constitute the guide region projection surface, which is the projection of the guide region onto the axial orthogonal projection surface. Polish the flow guide area; Inspect the aforementioned flow guidance area.

2. The method for modifying the blades of the inducer according to claim 1, characterized in that, The step of determining the diversion area further includes: marking the diversion area, the step of marking the diversion area includes, The image showing the projection surface of the flow guiding area is projected onto the non-working surface; The guide area is shown by a projection plane of the guide area projected onto the non-working surface; Alternatively, a marking tool can be used to mark along the edge of the projection surface of the guide area.

3. The method for modifying the blades of the inducer according to claim 1, characterized in that, The step of inspecting the flow guidance area includes: Mark the flow trajectory line segment; Select at least two measurement points within the flow trajectory segment; Measure the thickness value H2 at each of the measurement points, and measure the distance L2 between the measurement point and the starting point in the same flow trajectory segment; Compare the slope values ​​K2 of multiple measurement points, which satisfy the relationship: K2=L2 / H2.

4. The method for modifying the blades of the inducer according to claim 3, characterized in that, In the step of marking the flow trajectory segment, The image with the projected line segments of the flow trajectory drawn is projected onto the non-working surface; The flow trajectory segment is illustrated by the projection line segment of the flow trajectory onto the non-working surface.

5. The method for modifying the blades of the inducer according to any one of claims 1 to 4, characterized in that, The leading edge of the blade has an initial edge, and the initial region line is the line formed by the initial edge.

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