Resistance-reducing antifouling microstructure centrifugal pump blade, impeller and centrifugal pump

Abstract

The microstructural centrifugal pump blade comprises a blade body, a mushroom-shaped pit array is distributed on the front edge of the suction surface of the blade body, a sharkskin placoid scale-shaped protrusion array is distributed on the tail edge of the pressure surface of the blade body, and preferably, the mushroom-shaped pit array and the sharkskin placoid scale-shaped protrusion array are distributed on the front edge of the suction surface of the blade body. The sharkskin placoid scale-shaped bulge array is positioned at the 1 / 3 part of the tail part of the pressure surface; the sharkskin placoid scale-shaped protrusion array microstructures are arranged on the tail edges of the blades, so that the blades can effectively optimize the flow characteristic of the surface of the impeller, the mushroom-shaped pit array microstructures are arranged on the front edges of the blades, the speed difference at an inlet of the impeller can be increased, and the two microstructures are compounded to improve the overall performance of the centrifugal pump; and particularly, the performance is obviously improved under the working condition of medium and high flow.

Description

Technical Field

[0001] This invention relates to the field of centrifugal pump impeller technology, and in particular to a microstructured centrifugal pump blade, impeller, and centrifugal pump with drag reduction and anti-fouling properties. Background Technology

[0002] Centrifugal pumps convert mechanical energy into the potential, pressure, and kinetic energy of a fluid through the high-speed rotation of the impeller, achieving liquid lifting or pressurization. The centrifugal pump continuously performs work through the high-speed rotation of the impeller, converting input mechanical energy into the kinetic, pressure, and potential energy of the fluid, thereby achieving the engineering goal of lifting liquid in a storage tank to a specified height or obtaining the required system pressure. As the core working component, the impeller's structure directly determines the pump's key performance characteristics. By arranging sharkskin-like microstructures on the trailing edge of the impeller blades and mushroom-shaped recesses on the leading edge, its drag reduction and anti-fouling effects can be significantly improved, resulting in higher efficiency and a longer service life.

[0003] With the increasing demands of production and daily life, people have higher requirements for the performance of centrifugal pumps (such as efficiency, service life, and safety). However, current research on centrifugal pump blades mostly focuses on single factors such as drag reduction and chemical coating for antifouling. There is a lack of research on the synergistic application of drag reduction and antifouling through physical means (microstructure arrangement) in centrifugal pump impeller applications. Therefore, theoretically, incorporating microstructures into the design of centrifugal pump blades can reduce energy loss in the impeller and enhance antifouling effects. This is of great significance for improving the drag reduction performance and service life of centrifugal pump blades.

[0004] Chinese patent "CN217633089U" provides a microstructure blade that significantly improves hydrodynamic performance (stabilizing flow and reducing drag, delaying cavitation, and reducing noise and increasing efficiency) by symmetrically setting fish-scale-shaped grooves on the suction and pressure surfaces on both sides of the leading edge. However, the impeller microstructure grooves are only arranged in the leading edge region, and the effect on turbulence suppression in the middle and rear sections of the impeller is limited.

[0005] Chinese patent "CN213684665U" discloses a biomimetic centrifugal pump blade with a Koch fractal microtexture, featuring a Koch snowflake-shaped pit texture at the tip of the blade's suction surface. This structure reduces drag and noise by inducing micro-vortices, suppresses flow separation, and comprehensively improves the centrifugal pump's performance. However, since the texture only acts on the suction and pressure surfaces without synergistic optimization, it can easily lead to pressure differential imbalances on both sides of the blade. Chinese patent "CN118030600A" discloses a microfluidic biomimetic impeller blade with a non-smooth surface featuring a biomimetic fish-scale structure. The blade's suction and pressure surfaces are designed with a tile-like fish-scale structure. This non-smooth surface can reduce drag, suppress flow, lower operating noise, and optimize flow characteristics. The patent focuses on the rear chord length of the blade (the rear third), a region prone to boundary layer thickening, flow separation, and strong shear dissipation, and also the area where vortex and shear interactions are most pronounced. While wall friction exists on both the blade's leading edge and pressure surface, the leading edge is a fluid acceleration zone where microtexture disturbances could disrupt flow adhesion. The pressure surface primarily bears the load transfer and the conversion of mechanical energy to kinetic energy; therefore, the leading edge of the pressure surface is unsuitable for this fish-scale microstructure.

[0006] To address the shortcomings of existing microstructured surface blade technology for centrifugal pumps, it is necessary to develop a centrifugal pump impeller with biomimetic sharkskin microstructured blades. This would optimize centrifugal pump performance, improve drag reduction and anti-fouling properties, and enable the production of centrifugal pumps that meet the growing industrial demand for high efficiency and long service life. Summary of the Invention

[0007] The purpose of this invention is to address the technical deficiencies in the existing technology by providing a microstructured centrifugal pump blade with drag reduction and anti-fouling properties.

[0008] Another object of the present invention is to provide a centrifugal pump impeller.

[0009] Another object of the present invention is to provide a centrifugal pump.

[0010] The technical solution adopted to achieve the purpose of this invention is: A microstructure centrifugal pump blade with drag reduction and anti-fouling features includes a blade body. The leading edge of the suction surface of the blade body is provided with a mushroom-shaped array of recesses, and the trailing edge of the pressure surface of the blade body is provided with a sharkskin shield-shaped array of protrusions. Preferably, the sharkskin shield-shaped array of protrusions is located at one-third of the tail of the pressure surface. The sharkskin shield-shaped protrusion array includes multiple protrusion units, which are arranged alternately in different rows. Each protrusion unit includes a first rib, and two second ribs, two third ribs, and two fourth ribs symmetrically distributed on both sides of the first rib.

[0011] In the above technical solution, the lengths of the first rib, the second rib, the third rib, and the fourth rib gradually decrease, while their heights and widths are the same. The spacing between the first rib and the second rib, the second rib and the third rib, and the third rib and the fourth rib is the same.

[0012] In the above technical solution, the sharkskin shield-shaped protrusion array is dimensionless, and the formula is as follows: In the formula, s+ is the distance between the first ribs of two adjacent protruding units in the same row after dimensionless transformation, and s is the spacing c; The shear rate of the pressure surface wall; This represents the shear stress on the pressure surface wall; For fluid density; The kinematic viscosity of the fluid.

[0013] In the above technical solution, the mushroom-shaped pit array includes multiple grooves arranged sequentially in the horizontal and vertical directions, and each groove includes a first circular groove and a second circular groove that are connected vertically.

[0014] In the above technical solution, the first circular groove located at the bottom and the second circular groove located at the top are coaxially arranged, and the diameter d of the first circular groove is smaller than the diameter D of the second circular groove.

[0015] Another aspect of the present invention includes a centrifugal pump impeller, comprising a front cover plate, a rear cover plate, and a plurality of microstructured centrifugal pump blades arranged circumferentially between the front cover plate and the rear cover plate, wherein an impeller inlet is provided at the center of the front cover plate, and the front cover plate and the rear cover plate are spaced apart to form an impeller outlet.

[0016] Another aspect of the invention includes a centrifugal pump comprising the centrifugal pump impeller.

[0017] Compared with the prior art, the beneficial effects of the present invention are: 1. The trailing edge of the blade of the present invention is arranged with a sharkskin shield-shaped array of microstructures, which enables the blade to effectively optimize the flow characteristics of the impeller surface. The leading edge of the blade is arranged with a mushroom-shaped array of microstructures, which can increase the velocity difference at the impeller inlet. The combination of the two microstructures improves the overall performance of the centrifugal pump, especially showing a significant performance improvement under medium and high flow conditions.

[0018] 2. The sharkskin-scale protrusion array biomimetic microstructure arranged on the trailing edge of the blade of the present invention can suppress turbulent dissipation. By regulating the flow field, the biomimetic microstructure not only reduces energy loss, but also improves energy utilization efficiency.

[0019] 3. By arranging a sharkskin-skin-shaped array of protrusions on the trailing edge of the blade, the wall shear resistance at the blade exit end is reduced. Arranging a mushroom-shaped array of pits on the leading edge can optimize the vortex structure distribution, effectively increasing the contact area between the fluid and the blade. This improves the anti-fouling characteristics without affecting the flow adhesion, increases the impeller's service life, and reduces operating costs. Attached Figure Description

[0020] Figure 1This is a schematic diagram of the overall structure of the microstructure centrifugal pump blade of the present invention.

[0021] Figure 2 This is a partially enlarged view of the trailing edge of the microstructure centrifugal pump blade of the present invention.

[0022] Figure 3 This is a schematic diagram (top view) of a single protruding unit.

[0023] Figure 4 for Figure 3 The left view.

[0024] Figure 5 This is a partial enlarged view of the leading edge of the microstructure centrifugal pump blade of the present invention.

[0025] Figure 6 This is a partial top view of the mushroom-shaped array of pits.

[0026] Figure 7 for Figure 6 AA section view.

[0027] Figure 8 This is a schematic diagram of the overall structure of a centrifugal pump impeller.

[0028] Figure 9 This is a schematic diagram of the internal structure of a centrifugal pump impeller.

[0029] Figure 10 The graph shows the torque and efficiency of the centrifugal pump impeller in Example 2 and the original impeller at various flow rates.

[0030] Figure 11 The speed cloud diagrams are for the centrifugal pump in Example 3 and the original centrifugal pump under standard operating conditions.

[0031] Figure 12 This is a diagram of the shear force on the pressure surface of a single blade of a centrifugal pump impeller.

[0032] Figure 13 This is a diagram showing the entropy production of the pressure surface of a single blade in a centrifugal pump impeller.

[0033] Wherein, 1: blade body, 2: front cover plate, 3: rear cover plate, 4: impeller inlet, 5: impeller outlet, 6: sharkskin shield scale-shaped protrusion array, 6.1: protrusion unit, 6.11: first rib, 6.12: second rib, 6.13: third rib, 6.14: fourth rib, 7: mushroom-shaped pit array, 7.1: groove unit, 7.11: first circular groove, 7.12: second circular groove. Detailed Implementation

[0034] The present invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0035] Example 1 like Figures 1-6 As shown, a microstructure centrifugal pump blade with drag reduction and anti-fouling features includes a blade body 1. The leading edge of the suction surface of the blade body 1 is provided with a mushroom-shaped pit array 7, and the trailing edge of the pressure surface of the blade body 1 is provided with a sharkskin shield scale-shaped protrusion array 6. Preferably, the sharkskin shield scale-shaped protrusion array 6 is located at one-third of the tail of the pressure surface.

[0036] like Figures 2-4 As shown, the sharkskin shield-shaped protrusion array 6 includes multiple protrusion units 6.1, which are arranged alternately in different rows. Each protrusion unit 6.1 includes a first rib 6.11, and two second ribs 6.12, two third ribs 6.13 and two fourth ribs 6.14 symmetrically distributed on both sides of the first rib 6.11.

[0037] Furthermore, the lengths of the first rib 6.11 (L1=500μm), the second rib 6.12 (L2=350μm), the third rib 6.13 (L3=180μm), and the fourth rib 6.14 (L4=40μm) gradually decrease, while their height H=70μm and width t=40μm are the same. The distance c between the first rib 6.11 and the second rib 6.12, the second rib 6.12 and the third rib 6.13, and the third rib 6.13 and the fourth rib 6.14 is 20μm. Furthermore, the sharkskin-skin-like scale-shaped protrusion array 6 is dimensionless, and the formula is as follows: In the formula, s+ is the dimensionless distance between the first ribs 6.11 of two adjacent raised units 6.1 in the same row, and s is the spacing c; The shear rate of the pressure surface wall; This represents the shear stress on the pressure surface wall; For fluid density; Let be the kinematic viscosity of the fluid. Preferably, the dimensionless sharkskin shield-shaped protrusion array 6 has a size s+ of 18.5.

[0038] like Figures 5-7 As shown, the mushroom-shaped pit array 7 includes a plurality of groove units 7.1 arranged in a horizontal and vertical sequence. Each groove unit 7.1 includes a first circular groove and a second circular groove 7.12 that are connected vertically. The centers of the first circular groove located at the bottom and the second circular groove located at the top are coaxially arranged. The diameter d of the first circular groove is smaller than the diameter D of the second circular groove 7.12.

[0039] Example 2 like Figures 8-9 As shown, this embodiment provides a centrifugal pump impeller, including a front cover plate 2, a rear cover plate 3, and a plurality of microstructure centrifugal pump blades as described in Embodiment 1 arranged circumferentially between the front cover plate 2 and the rear cover plate 3. An impeller inlet is provided at the center of the front cover plate 2, and the front cover plate 2 and the rear cover plate 3 are spaced apart to form an impeller outlet 5. Preferably, the number of microstructure centrifugal pump blades is 5, the outer diameter D1 of the front cover plate 2 or the rear cover plate 3 is 150 mm, the diameter of the inlet is D2 is 60 mm, and the gap s between the front cover plate 2 and the rear cover plate 3 is 4.7 mm.

[0040] Example 3 This embodiment provides a centrifugal pump, including the centrifugal pump impeller described in the embodiment. During the operation of the centrifugal pump, the fluid first enters from the impeller inlet at the center of the front cover plate 2, and is then pushed into the flow channel between adjacent microstructure centrifugal pump blades under the action of centrifugal force generated by rotation, and finally discharged through the impeller outlet 5 at the outer edge of the impeller.

[0041] By arranging a sharkskin-scale-shaped protrusion array6 on one-third of the pressure surface of a microstructured centrifugal pump blade, the fluid flow can be disturbed, affecting not only the boundary layer characteristics but also guiding the fluid to form a stable vortex structure on the blade surface. The vortex lift effect, as an effective flow control mechanism, can significantly improve the flow stability of the blade surface, thereby reducing energy loss caused by fluid separation. This reduces impeller energy loss and improves the efficiency of the centrifugal pump.

[0042] like Figure 10 As shown, the design speed of this embodiment is 3450 r / min, the flow rate is 15 kg / s, and the head is 34 m. The efficiency and torque values ​​of the centrifugal pump described in Example 3 under design conditions (0.4 times to 1.6 times the standard condition). Resistance increase rate. and increase efficiency The calculation formula is as follows: In the formula: The torque of the original impeller (with smooth blades); The torque of the impeller (microstructure impeller) in Example 2; The original impeller centrifugal pump (smooth blades) efficiency; The efficiency of the centrifugal pump (microstructure impeller centrifugal pump) in Example 3 is shown.

[0043] When the flow rate is lower than the design condition, the efficiency of the microstructured centrifugal pump blades in Example 1 is generally lower than that of the smooth blades, with a negative increase in efficiency. When Q / Qd = 0.4, the increase in efficiency is -1.9%, and the increase in drag is 2.63%, indicating that the microstructured centrifugal pump blades not only failed to effectively improve the flow characteristics at this stage, but also increased turbulent dissipation due to the influence of surface roughness, leading to a decrease in efficiency and an increase in resistance. At high flow rates, the performance advantages of the microstructured centrifugal pump blades gradually become apparent, and the efficiency curve begins to surpass that of the smooth blades. When Q / Qd = 1.1, the efficiency surpasses that of the smooth blades, at which point the increase in efficiency turns from negative to positive, reaching 0.18%; simultaneously, the increase in drag gradually decreases to -1.71%. The torque performance at this stage also confirms the enhanced drag reduction effect of the microstructured centrifugal pump blades.

[0044] The total torque of the microstructured centrifugal pump blades is slightly higher than that of the smooth blades at low flow rates. At Q / Qd = 0.4, the torque of the microstructured blades is approximately 4.5 N·m, while that of the smooth blades is approximately 4.3 N·m, indicating that the microstructured centrifugal pump blades do not fully demonstrate their drag reduction advantage at this stage. However, as the flow rate gradually increases, the trends of both efficiency and drag ratio gradually improve. The efficiency increases from -0.45% to 0.18%, and the drag ratio decreases from 0.8% to a minimum of -2.27%, indicating that the negative impact of the microstructured centrifugal pump blades on turbulent energy dissipation begins to gradually weaken. When Q / Qd ≈ 1.0, the torque of the microstructured centrifugal pump blades begins to be lower than that of the smooth blades, and at Q / Qd = 1.2, the efficiency reaches its highest value of 0.18%, and the drag ratio reaches -1.71%. Thereafter, this trend gradually weakens with increasing flow rate. It is evident that, in the medium to high flow rate stage, the microstructure centrifugal pump blades become increasingly effective in optimizing turbulent structure, weakening secondary flow, and suppressing boundary layer separation. This not only improves the energy utilization of the fluid but also reduces the total resistance, demonstrating its superior drag reduction and efficiency enhancement performance as well as its anti-fouling properties.

[0045] like Figure 11 As shown, comparing the velocity contour maps of the original impeller centrifugal pump (with smooth blades and no microstructure), it was found that the microstructure centrifugal pump has a larger low-velocity liquid zone at impeller inlet 4 compared to the original impeller centrifugal pump; however, the liquid velocity near the wall is higher than that of the original impeller centrifugal pump. This indicates that the arrangement of the microstructure centrifugal pump blades increases the velocity difference of the liquid flowing over the blade surface, which is more conducive to the liquid scouring the blade surface, preventing algae adhesion, and significantly improving its anti-fouling performance.

[0046] like Figures 12-13As shown, the distribution of shear force and entropy production on the pressure surface of a centrifugal pump blade under standard operating conditions indicates that the high-value areas are concentrated in the trailing third of the pressure surface. Based on this, arranging a sharkskin-skin scale-shaped protrusion array at the trailing third of the pressure surface is a low-cost and efficient solution. Results show that after introducing the sharkskin-skin scale-shaped protrusion array microstructure, the shear force on the pressure surface is significantly reduced, energy dissipation is decreased, and drag reduction and efficiency improvement are effectively achieved.

[0047] The above description is only a preferred embodiment of the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A microstructured centrifugal pump blade with drag reduction and anti-fouling properties, characterized in that, The blade body includes a mushroom-shaped array of recesses on the leading edge of the suction surface of the blade body and a sharkskin shield-shaped array of protrusions on the trailing edge of the pressure surface of the blade body. The sharkskin shield-shaped protrusion array includes multiple protrusion units, which are arranged alternately in different rows. Each protrusion unit includes a first rib, and two second ribs, two third ribs, and two fourth ribs symmetrically distributed on both sides of the first rib.

2. The microstructured centrifugal pump blade according to claim 1, characterized in that, The sharkskin-skin-like array of protruding scales is located at one-third of the tail of the pressure surface.

3. The microstructured centrifugal pump blade according to claim 1, characterized in that, The lengths of the first, second, third, and fourth ribs gradually decrease, while their heights and widths are the same.

4. The microstructured centrifugal pump blade according to claim 1, characterized in that, The spacing between the first rib and the second rib, the second rib and the third rib, and the third rib and the fourth rib is the same.

5. The microstructured centrifugal pump blade according to claim 1, characterized in that, The sharkskin shield-shaped protrusion array is dimensionless, and the formula is as follows: In the formula, s+ is the distance between the first ribs of two adjacent protruding units in the same row after dimensionless transformation, and s is the spacing c; The shear rate of the pressure surface wall; This represents the shear stress on the pressure surface wall; For fluid density; The kinematic viscosity of the fluid.

6. The microstructured centrifugal pump blade according to claim 1, characterized in that, The mushroom-shaped pit array includes multiple grooves arranged sequentially in the horizontal and vertical directions, and each groove includes a first circular groove and a second circular groove that are connected vertically.

7. The microstructured centrifugal pump blade according to claim 1, characterized in that, The centers of the first circular groove located at the bottom and the second circular groove located at the top are set coaxially.

8. The microstructured centrifugal pump blade according to claim 1, characterized in that, The diameter d of the first circular groove is smaller than the diameter D of the second circular groove.

9. A centrifugal pump impeller, characterized in that, The pump comprises a front cover plate, a rear cover plate, and a plurality of microstructured centrifugal pump blades of any one of claims 1 to 8 arranged circumferentially between the front cover plate and the rear cover plate, wherein an impeller inlet is provided at the center of the front cover plate, and the front cover plate and the rear cover plate are spaced apart to form an impeller outlet.

10. A centrifugal pump, characterized in that, Includes the centrifugal pump impeller as described in claim 9.

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