Induced wheel with periodically varying wall

Abstract

The application discloses an inducer wheel with periodically changed wall surface. The inducer wheel comprises two inducer blades, a wheel hub and a periodic shell, the wheel hub is coaxially arranged in the inner center of the periodic shell, the two inducer blades are arranged between the wheel hub and the inner wall surface of the inducer shell, and the radial inner ends of the two inducer blades are connected to the outer side circumferential surface of the wheel hub. The inducer wall surface structure scheme is designed by changing the inducer wall surface parameters on the basis of the basic model of the inducer, the sinusoidal curve is uniformly distributed on the wall surface of the original inducer, and the inducer reaches the modification purpose. The inducer after modification has a range of blade tip clearance instead of a fixed value, so that the inducer after modification has the advantages of small and large blade tip clearance, avoids the large inducer inlet backflow caused by large blade tip clearance and energy loss, and also avoids the large wheel hub flow split caused by small blade tip clearance and energy loss.

Description

Technical Field

[0001] This invention relates to an inducer wheel, and more specifically to an inducer wheel with periodically changing wall surface. Background Technology

[0002] The inducer in a centrifugal pump, also known as a pre-implantation impeller, is an axial-flow impeller installed at the front of the centrifugal pump impeller. The centrifugal pump utilizes the head generated by the inducer to boost the pressure of the subsequent impeller. Currently, adding an inducer at the inlet is one of the most effective and commonly used methods to improve the cavitation performance of a centrifugal pump. The inducer improves the suction performance of the centrifugal pump; its small inlet angle of attack, fewer blades, low blade load, and high blade density not only result in good cavitation performance itself but also increase the inlet fluid energy of the centrifugal impeller. Furthermore, when the cavitation margin of the device is insufficient, it can extend the service life of flow components such as the impeller, pump body, and cover plate. In a centrifugal pump inducer, a small blade tip clearance leads to a large flow diversion at the inducer hub, causing severe flow instability and resulting in energy loss. Simultaneously, cavitation mainly occurs at the tip of the inducer blades, and the smaller the clearance, the easier it is for cavitation to occur. Conversely, a large blade tip clearance results in a larger inlet return flow area, also causing flow instability and energy loss. Whether the blade tip clearance is large or small, it will have a negative impact on the performance of the inducer.

[0003] In actual industrial production, the shell of traditional inducer is often round. Although this can avoid the adverse effects of excessively large or small gaps to a certain extent, it cannot take into account the advantages of the inducer under different blade tip clearances. Therefore, the existing process structure needs to be improved. Summary of the Invention

[0004] To address the problems existing in the background art, the present invention provides an inducer with periodically varying blade clearance. The modified inducer has a periodically varying blade tip clearance within a certain range, while taking into account the advantages of the inducer under different blade tip clearances, allowing for further optimization of the inducer design and improving the cavitation performance of the centrifugal pump.

[0005] The technical solution adopted in this invention is:

[0006] The inducer wheel with periodically changing wall surface of the present invention includes two inducer wheel blades, a hub and a periodic outer shell. The hub is coaxially mounted at the inner center of the periodic outer shell. The two inducer wheel blades are located between the inner wall surface of the hub and the inducer wheel outer shell. The radial inner ends of the two inducer wheel blades are connected to the outer circumferential surface of the hub.

[0007] The periodic outer shell is a cylindrical structure with two open ends and a periodically varying wall surface. The cross-section of the periodic outer shell is a circular cross-section composed of sine curves with a preset period and amplitude. This inducer wheel is based on a basic inducer wheel model, with only the inducer wheel wall parameters modified without altering other geometric parameters. The periodic outer shell uses the circumference of the prototype inducer wheel wall as a baseline, on which sine curves are evenly arranged, transforming the wall surface from a circular shape to a periodically varying one. The blade tip clearance between the inducer wheel blades and the inner wall of the inducer wheel outer shell varies periodically during rotation, ranging from 0.3 to 0.7 mm.

[0008] The tip clearance ratio of the inducer blades is 12.2% to 28.6%, which is equal to the ratio between the tip clearance and the radius of the inducer blades. The periodic outer shell changes periodically to achieve a periodic change in the tip clearance, thereby simultaneously avoiding the adverse effects caused by excessively large or small tip clearances.

[0009] The two inducer blades are parallel to each other and evenly distributed with equal pitch along the length of the hub, with a gap between the radial outer ends of the two inducer blades and the inner wall of the inducer housing.

[0010] The two inducer blades have similar structures and shapes, and both are spirally ascending blades.

[0011] The hub is conical, with the end of the periodic outer shell near the apex of the hub being the inlet and the end away from the apex being the outlet. As the hub and the two inducer blades rotate, the fluid enters the inducer from the inlet and flows out from the outlet.

[0012] The inner edges of the two inducer blades are welded to the circumferential side of the upper part of the hub to form a hub inducer structure. The tops of the two inducer blades are fixedly connected to the upper end of the hub, so that the two inducer blades rotate with the hub as the axis center.

[0013] The beneficial effects of this invention are:

[0014] The periodically varying wall surface in this invention is a modification of the prototype inducer. Because the wall surface is periodically varied, the blade tip clearance also varies periodically. This design takes into account the advantages of the inducer under different blade tip clearances, allowing for further optimization of the inducer design and improving the cavitation and cavitation performance of the centrifugal pump.

[0015] This invention is based on the basic model of an inducer. Without changing other geometric parameters, only the inducer wall parameters are modified to design an inducer wall structure scheme. Using the perimeter of the prototype inducer wall as a baseline, sine curves are evenly distributed on it to achieve the purpose of modifying the inducer. The modified inducer blade tip clearance is not a constant value but a range. Therefore, the modified inducer combines the advantages of both small and large blade tip clearances, avoiding the large inlet backflow caused by a large blade tip clearance, which would result in energy loss; at the same time, it also avoids the large hub flow diversion caused by a small blade tip clearance, which would result in energy loss. Attached Figure Description

[0016] Figure 1 This is a perspective view of the periodic outer shell of the present invention;

[0017] Figure 2 This is a front view of the periodic outer shell of the present invention;

[0018] Figure 3 This is a front view of the inducer wheel of the present invention;

[0019] Figure 4 This is a rear view of the inducer wheel of the present invention;

[0020] Figure 5 This is a cross-sectional view of the inducer wheel of the present invention;

[0021] Figure 6 This is a perspective view of the inducer wheel of the present invention;

[0022] In the diagram: 1. Inducer blades, 2. Hub, 3. Periodic outer shell. Detailed Implementation

[0023] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0024] The inducer wheel of the present invention with periodic wall changes includes two inducer wheel blades 1, a hub 2 and a periodic outer shell 3. The hub 2 is coaxially mounted in the inner center of the periodic outer shell 3. The two inducer wheel blades 1 are located between the inner wall surfaces of the hub 2 and the inducer wheel outer shell 3. The radial inner ends of the two inducer wheel blades 1 are connected to the outer circumferential surface of the hub 2.

[0025] The periodic outer shell 3 is a cylindrical structure with two open ends and a periodically varying wall surface. The cross-section of the periodic outer shell 3 is a circular cross-section composed of sine curves with a preset period and amplitude. This inducer wheel is based on the basic inducer wheel model, with only the inducer wheel wall parameters modified without altering other geometric parameters. The periodic outer shell 3 uses the perimeter of the prototype inducer wheel wall as a baseline, on which sine curves are uniformly arranged, transforming the wall surface from a circle to a periodically varying shape.

[0026] When the inducer blade 1 rotates, the blade tip clearance between it and the inner wall of the inducer housing 3 changes periodically, and the blade tip clearance varies from 0.3 to 0.7 mm.

[0027] The tip clearance ratio of the inducer blade 1 is 12.2% to 28.6%, which is equal to the ratio between the tip clearance and the radius of the inducer blade 1. The periodic outer shell 3 changes periodically to achieve a periodic change in the tip clearance, thereby avoiding the adverse effects caused by both excessively large and excessively small tip clearances.

[0028] The two inducer blades 1 are parallel to each other and evenly distributed with equal pitch along the length of the hub 2. A gap is left between the radial outer ends of the two inducer blades 1 and the inner wall of the inducer housing 3. The two inducer blades 1 have similar structures and shapes and are both spirally ascending blades.

[0029] The hub 2 is conical. The end of the periodic outer shell 3 near the apex of the hub 2 is the inlet end, and the end away from the apex of the hub 2 is the outlet end. When the hub 2 and the two inducer blades 1 rotate, the fluid enters the inducer from the inlet end and flows out of the inducer from the outlet end.

[0030] The inner edges of the two inducer blades 1 are welded to the circumferential side of the upper part of the hub 2 to form a hub inducer structure. The tops of the two inducer blades 1 are fixedly connected to the upper end of the hub 2, so that the two inducer blades 1 rotate with the hub 2 as the axis center.

[0031] like Figure 1 and Figure 2 As shown, the periodically changing outer shell of this invention is derived from the circular wall of the prototype inducer. Using the circumference of the prototype wall as a baseline, sinusoidal curves are uniformly distributed on it. The number of periods and amplitude of the distributed sinusoidal curves can be changed. This invention selects a period number of 48 and an amplitude of 0.4. By determining these two parameters, the final outer wall surface is obtained. Figure 3 and Figure 4 The image shows the front and rear views of the modified inducer. The front view shows the fluid inlet, and the rear view shows the fluid outlet.

[0032] like Figure 5 and Figure 6As shown, the tip clearance of the inducer is 0.3–0.7 mm. This avoids the energy loss caused by excessively small tip clearance leading to large flow diversion at the hub, while cavitation mainly occurs at the tip of the inducer blades, and the smaller the clearance, the easier it is to cause cavitation. Conversely, excessively large tip clearance leads to large backflow at the inducer inlet, also causing energy loss. The periodic outer shell changes periodically, and therefore the tip clearance also changes periodically. This design balances the advantages of different tip clearances for the inducer, allowing for further optimization of the inducer design and improving the cavitation and cavitation performance of the centrifugal pump.

Claims

1. A wall periodic variation inducing wheel, characterized in that: The inducer wheel comprises two inducer blade (1), hub (2) and periodic shell (3), the hub (2) is coaxially installed in the inside center of the periodic shell (3), two inducer blade (1) is located between the hub (2) and the inner wall of the periodic shell (3), the radial inner end of two inducer blade (1) is connected on the outer side of the hub (2) circumferential surface; The periodic shell (3) is a through cylinder structure with wall surface periodic variation, the cross section of the periodic shell (3) is a circular cross section composed of a sine curve with a preset period and a preset amplitude; The inducer blade (1) is periodically changed between the inducer blade (1) and the inner wall of the periodic shell (3) when rotating, and the range of the tip clearance is 0.3-0.7mm.

2. The inducer wheel of claim 1, wherein: The inducer blade (1) is periodically changed between the inducer blade (1) and the inner wall of the periodic shell (3) when rotating, and the range of the tip clearance is 0.3-0.7mm.

3. The inducer wheel of claim 1, wherein: The inducer blade (1) is periodically changed between the inducer blade (1) and the inner wall of the periodic shell (3) when rotating, and the range of the tip clearance is 0.3-0.7mm.

4. The inducer wheel of claim 1, wherein: The inducer blade (1) is periodically changed between the inducer blade (1) and the inner wall of the periodic shell (3) when rotating, and the range of the tip clearance is 0.3-0.7mm.

5. The inducer wheel of claim 1, wherein: The inducer blade (1) is periodically changed between the inducer blade (1) and the inner wall of the periodic shell (3) when rotating, and the range of the tip clearance is 0.3-0.7mm. The inducer blade (1) is periodically changed between the inducer blade (1) and the inner wall of the periodic shell (3) when rotating, and the range of the tip clearance is 0.3-0.7mm. The inducer blade (1) is periodically changed between the inducer blade (1) and the inner wall of the periodic shell (3) when rotating, and the range of the tip clearance is 0.3-0.7mm.

Images