Centrifugal pump volute with composite noise reduction structure

Abstract

The present application belongs to the field of fluid machinery, and discloses a centrifugal pump volute with a composite noise reduction structure, which comprises a volute body with a base circle radius R, a volute chamber is formed inside the volute body, and a plurality of micro guide vanes are distributed in the circumferential direction on the inner side of the inlet of the volute body; two semicircular grooves are arranged on the upstream segment of the volute chamber inner wall baffle in front and back symmetry along the spiral line; two guide plates are arranged at the baffle of the volute body, the guide plate close to the inlet side of the volute body is a front guide plate, and a plurality of guide holes are formed on the front guide plate; a plurality of cavities are uniformly arrayed on the wall surface of the baffle of the volute body; and the bending directions of the micro guide vanes and the guide plates are consistent with the water flow direction. The present application optimizes the inlet flow through the micro guide vanes, suppresses vortex through the semicircular grooves, and cooperatively reduces the pressure pulsation through the guide plate and the cavity structure, so that the fluid noise is effectively reduced while the hydraulic performance is maintained, and the comprehensive performance is obviously improved.

Description

Technical Field

[0001] This invention relates to the field of fluid machinery, and more particularly to a centrifugal pump casing with a composite noise reduction structure. Background Technology

[0002] Centrifugal pumps, widely used in industrial fluid transport, have always faced significant challenges due to operational noise, which negatively impacts equipment performance and the working environment. The volute of a centrifugal pump, a key energy conversion component, exhibits complex internal flow characteristics, making it a primary source of fluid noise. Studies show that unsteady flow within the volute generates significant broadband turbulent noise and discrete-frequency pulsating noise. Specifically, the dynamic-static interference between the impeller and the volute tongue induces strong pressure pulsations, with the fundamental frequency being the blade passing frequency (fBPF) and its harmonic components. Furthermore, secondary flows and separated flows within the volute further exacerbate flow instability, leading to a significant increase in noise levels.

[0003] Experimental data shows that under rated operating conditions, the noise radiated by the volute casing can account for more than 40% of the total pump noise, and is particularly prominent in the mid-to-high frequency range. This not only affects the stable operation of the centrifugal pump but also causes significant noise pollution to the surrounding working environment. With increasingly stringent environmental protection requirements, reducing the operating noise of centrifugal pumps has become an important issue in improving their overall performance.

[0004] Traditional noise reduction methods mainly include optimizing the volute profile or increasing the wall thickness. While these methods can reduce noise to some extent, they often fail to simultaneously meet the hydraulic performance and noise reduction requirements of centrifugal pumps. Therefore, developing a novel composite volute noise reduction structure to achieve synergistic design of flow field optimization and acoustic control has become an important research direction in the current development of centrifugal pump technology. Summary of the Invention

[0005] The purpose of this invention is to provide a centrifugal pump volute with a composite noise reduction structure, which effectively suppresses the noise generated by the unstable flow inside the volute during centrifugal pump operation, significantly reducing the noise level of the centrifugal pump, thereby making its operation more stable, and simultaneously meeting the dual goals of environmental protection requirements and equipment performance.

[0006] To achieve the above objectives, the present invention provides the following solution: a centrifugal pump casing with a composite noise reduction structure, comprising a base circle radius of... RThe volute body has a volute chamber inside, and multiple micro-guide vanes are distributed circumferentially on the inner side of the inlet of the volute body. Two semi-circular grooves are symmetrically arranged along a spiral line on the upstream section of the tongue of the inner wall of the volute body. Two guide plates are provided at the tongue of the volute body, and the guide plate near the inlet of the volute body is the front guide plate, which has several guide holes. Several cavities are evenly arrayed on the wall surface of the tongue of the volute body. The bending direction of the micro-guide vanes and the guide plates is consistent with the direction of water flow.

[0007] Multiple micro-guide vanes (3) are evenly arranged at equal angles at the inlet of the volute, with the included angle between two adjacent micro-guide vanes (3) being... α The height of the micro-guide plate (3) is 55°~60°. H 3 It is 0.2~0.3 R ,width D 5 The value is 0.05~0.08. R The number of micro-guide plates (3) is n , n for , round This indicates rounding to the nearest integer.

[0008] The outlet tangent of the micro-guide plate (3) forms a guide angle of 15°~20° with the inner wall tangent of the volute body (1). γ The profile equation of the micro-guide plate (3) is:

[0009] ,

[0010] in, The coordinates are 0~1, and the origin is the center of the base circle of the volute body (1). R 5 The radius of the rounded corner at the outlet end of the micro-guide plate (3) is given.

[0011] Optionally, the outlet end of the micro-guide plate has a rounded fillet radius. R 5 The range is 0.008~0.01 R .

[0012] Optionally, the radius of the semi-circular groove R 1 It is 0.006 R The angles of the inlet and outlet ends of the semi-circular groove β It is 0.9 α .

[0013] Optionally, the length of the front guide vane D 1 It ranges from 0.8 to 1.0.R The height is 0.8~0.84. R radius of curvature R 3 The value is between 0.36 and 0.44. R .

[0014] Optionally, the front guide vane has guide holes on its water-facing surface, the radius of which is... R 2 It is 0.01 R The number of guide holes is n 1 , n 1 =round , k =0.8~1.2, round means rounding to the nearest integer. D 1 It is the length of the front spoiler (4). H 1 The height of the front guide vane (4) is given.

[0015] Optionally, the guide vane on the side furthest from the inlet of the volute body is a rear guide vane, and the length of the rear guide vane is... D 2 The value is 0.96~1.2. R ,high H 2 The value ranges from 0.96 to 1.04. R radius of curvature R 4 The value is 0.43~0.53. R It forms a curvature radius ratio of 1.2 with the front spoiler.

[0016] Optionally, the distance between the front deflector and the rear deflector is... D , D =0.16~0.24 R .

[0017] Optionally, the profile equation of the guide vane is:

[0018]

[0019] in, ξ The coordinates range from 0 to 1, with the origin being the center of the base circle of the volute body.

[0020] Optionally, the distance from the outlet of the semi-circular groove to the leading edge of the front guide vane is... D 3 , D 3 =0.1~0.14 R .

[0021] Optionally, the cavities are arranged in a rectangular array, are cylindrical in shape, and have a diameter of D 4 It is 0.014 R Array spacing S 1 It is 0.003 R , S 2 It is 0.003 R .

[0022] Optionally, the number of cavities n 2 With the number of guide holes n 1 Satisfying the relation .

[0023] Optionally, the micro-guide plate and the guide plate are made of the same material as the volute body, namely 304 stainless steel.

[0024] Compared with the prior art, the present invention discloses at least the following beneficial effects:

[0025] This application provides a centrifugal pump volute with a composite noise reduction structure. By optimizing inlet flow with micro guide vanes, suppressing eddies with semi-circular grooves, and reducing pressure pulsation through the synergistic effect of guide plates and cavity structures, it effectively reduces fluid noise while maintaining hydraulic performance, resulting in a significant improvement in overall performance. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 A schematic diagram of the internal structure of the centrifugal pump casing provided by the present invention;

[0028] Figure 2 This is a partial enlarged view of the interior of the centrifugal pump casing of the present invention;

[0029] Figure 3 for Figure 1 A magnified view of a section at point A in the middle;

[0030] Figure 4 This is a front view of the interior of the centrifugal pump casing of the present invention;

[0031] Figure 5 for Figure 4 Sectional view at point BB;

[0032] Figure 6 This is a schematic diagram of the micro-guide vane in the centrifugal pump casing of the present invention;

[0033] Figure 7 This is a schematic diagram of the structure of the front guide vane in the centrifugal pump casing of the present invention.

[0034] In the diagram: 1. Volute body; 2. Cavity; 3. Micro-guide vane; 4. Front guide plate; 5. Semi-circular groove; 6. Rear guide plate; 7. Guide hole. Detailed Implementation

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] In existing technologies, the complexity of internal flow within the centrifugal pump casing often generates fluid noise, primarily manifested as broadband turbulent noise and discrete frequency pulsating noise. Traditional noise reduction methods, such as profile optimization or increased wall thickness, can partially alleviate the problem, but they struggle to achieve an effective balance between hydraulic performance and acoustic control. For example, under rated operating conditions, the volute-radiated noise of a certain type of centrifugal pump accounts for over 40% of the total pump noise, with significant peaks, especially in the 800-2000Hz frequency band. Existing structures cannot effectively suppress noise in this frequency band while maintaining head efficiency.

[0037] To address these issues, researchers discovered that water flow separation at the volute inlet, dynamic-static interference in the tongue region, and secondary flow development are the main causes of noise generation. Based on flow stability theory, they proposed improving the flow regime through the synergistic effect of multi-stage rectifying structures: first, flow pre-regulation is implemented at the inlet; then, shear stress control is implemented in the middle section of the flow channel; and finally, pressure pulsation attenuation is achieved in the tongue region. This approach overcomes the technical bottleneck of the limited effective range of a single noise reduction structure, forming a composite flow field control scheme.

[0038] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0039] Reference Figures 1 to 7As shown, this invention provides a centrifugal pump volute with a composite noise reduction structure, including a volute body 1, which forms a volute chamber inside. Micro-guide vanes 3 are circumferentially arranged on the inlet side of the volute body 1. Two semi-circular grooves 5 are symmetrically arranged on the upstream section of the partition tongue on the inner wall of the volute chamber. A front guide plate 4 and a rear guide plate 6 with guide holes 7 are provided at the partition tongue, and cavity structures 2 are uniformly arrayed on the partition tongue wall. The bending direction of each structure is consistent with the direction of water flow, forming a continuous flow guidance system. The micro-guide vanes 3 are thin sheet structures arranged at the volute inlet, which can be implemented using an equal-angle distribution to reduce the risk of flow separation at the inlet section by dividing the main flow into multiple sub-flows. The semi-circular grooves 5 are recessed structures symmetrically arranged along a spiral line, which can be implemented using a continuous arc surface transition design to weaken the wall shear stress gradient. The guide plates are flow straightening components set at the partition tongue, which can be implemented using a curved panel structure. The front guide plate 4 has guide holes 7 to achieve flow splitting control. Cavity 2 is a regularly arranged resonant structure, which can be implemented using a cylindrical cavity array, and produces an acoustic filtering effect through a specific volume design.

[0040] After entering the volute, the water flow is first divided by the micro-guide vanes 3, forming a stable laminar flow. Subsequently, in the helical channel, the smooth transition surface of the semi-circular grooves 5 weakens boundary layer separation and reduces turbulent kinetic energy generation. When the water flow reaches the tongue region, the diversion holes of the front guide plate 4 divide the main flow into multiple streams, reducing direct impact on the leading edge of the tongue, while the rear guide plate 6 guides the water flow to a smooth transition. At the same time, the cavity array 2 selectively attenuates pressure pulsations of specific frequencies through the Helmholtz resonance principle. The synergistic effect of these structures achieves full-process control from flow stabilization to acoustic energy dissipation.

[0041] Based on the above technical solution, this application effectively solves the broadband noise problem caused by unsteady flow within the volute. In rated operating condition testing, the inlet micro-guide vane 3 reduces the water flow separation area by 30%-40%, the semi-circular groove 5 reduces the local shear stress peak by 15%-20%, the guide plate system reduces the pressure pulsation amplitude at the tongue by 25%-30%, and the cavity array 2 attenuates 500-2500Hz noise by 3-5 dB. The synergistic effect of these structures reduces the overall pump noise level by 6-10 dB(A) while maintaining hydraulic efficiency fluctuations within ±1.5%.

[0042] In one specific embodiment, the centrifugal pump casing of this embodiment includes a base circle radius of... R The centrifugal pump volute body 1 has multiple micro-guide vanes 3 evenly arranged circumferentially at equal angles on the inner side of the volute inlet. The included angle α between two adjacent micro-guide vanes 3 is 55°~60°, and the height of the micro-guide vanes 3 is... H 3 It is 0.2~0.3 R ,width D 5The value is 0.05~0.08. R 3 micro-guide plates n Determined by rounding to the nearest integer. Specifically, n for , round This indicates rounding to the nearest integer.

[0043] Further optimization of the scheme involves controlling the central angle between two adjacent micro-guide vanes 3 within a specific range to ensure uniform water flow segmentation upon entering the vortex chamber. The included angle α between two adjacent micro-guide vanes 3 is 55°~60°, representing the angle range between the centerlines of adjacent micro-guide vanes 3. This can be achieved by adjusting the number of vanes and the spacing angle. For example, when the base circle radius is fixed, this angle range can balance the flow segmentation effect with structural strength. The height of the micro-guide vane 3... H 3 It is 0.2~0.3 R This refers to the ratio of the radial extension length of the micro-guide vane 3 to the radius of its base circle. This ratio can be determined by optimizing the fluid dynamics model, for example, by ensuring effective flow guidance while avoiding excessive resistance to the main flow. The width of the micro-guide vane 3... D 5 It is the thickness dimension of the micro-guide plate 3 along the axial direction, specifically, D 5 The value is 0.05~0.08. R, D 5 The value of can be verified through flow field simulation to ensure its rationality, for example, by reducing flow separation while avoiding boundary layer thickening. Number of micro-guide vanes 3 n The rounding method determines the circumference by rounding the theoretical value calculated based on the base circle circumference and the included angle α. For example, the nearest integer is taken after calculation using a mathematical formula to ensure circumferential uniformity.

[0044] It should be understood that, in practical applications, by arranging the micro-guide vanes 3 at equal angles and optimizing their size ratio, the water flow can be more effectively divided into multiple stable sub-flows, significantly reducing flow separation and eddy intensity in the inlet region. This suppresses broadband noise generated by flow separation at the volute inlet and reduces the impact intensity of the water flow on the tongue region through uniform guiding, thereby reducing discrete frequency noise caused by dynamic-static interference.

[0045] The design was further optimized by rounding the outlet end of the micro-guide plate 3, with a rounding radius of [missing information]. R 5, R The range of 5 is 0.008~0.01. RThe rounding process involves machining a rounded transition structure at the trailing edge of the micro-guide vane 3, which can be achieved through mechanical grinding or CNC machining. This process creates a gradual flow separation as the water flows away from the guide vane, avoiding abrupt flow separation caused by sharp edges. (Rounded corner radius) R The range is set to 0.008 to 0.01 times the base circle radius. This ratio ensures that the flow separation point is controllable while maintaining the structural strength of the guide vanes, allowing the high-speed water flow to form a continuous velocity gradient distribution after detaching from the guide vanes. This effectively extends the starting position of flow separation, making the water flow velocity gradient more gradual and significantly reducing broadband noise caused by eddy shedding.

[0046] Further optimization involves creating a guiding angle γ between the outlet tangent of the micro-guide vane 3 and the inner wall tangent of the volute body 1. This guiding angle is controlled within the range of 15° to 20°, and the profile equation of the micro-guide vane 3 is defined as follows:

[0047] , ;

[0048] in, The coordinates range from 0 to 1, with the origin being the center of the base circle of the volute body 1.

[0049] The guide angle γ is the angle between the outlet tangent of the micro-guide vane 3 and the inner wall tangent of the volute body 1. Specifically, it can be within the range of 15° to 20°. This angle controls the water flow direction, reducing flow separation when the water impacts the inner wall of the volute, thereby suppressing turbulent noise. The profile equation defines the geometric profile of the micro-guide vane 3 using a quadratic function curve. By adjusting the γ value, the curvature of the micro-guide vane 3 is controlled, allowing the water flow to smoothly transition along the profile, reducing the local flow velocity gradient, and thus weakening the broadband noise caused by shear stress.

[0050] Further optimization involves symmetrically arranging two semi-circular grooves 5 along a spiral line on the upstream section of the diaphragm tongue inside the volute chamber. The radius of the semi-circular grooves 5 can be 0.006 times the radius of the base circle. The angles at the inlet and outlet ends of the semi-circular grooves 5 are... β It is 0.9 α This angle can be 0.9 times the included angle between adjacent micro-guide vanes 3. This angle range ensures a continuous transition between the rectified flow area of ​​the trench and the flow guiding area of ​​the micro-guide vane 3, avoiding flow interference.

[0051] Specifically, two semi-circular grooves 5 are symmetrically arranged in the upstream region of the tongue on the inner wall of the volute. The grooves are arranged along the spiral direction of the volute, and their radius of curvature is proportional to the radius of the base circle, for example, this ratio can be 0.006. The circumferential coverage angle between the inlet and outlet ends of the grooves maintains a specific proportional relationship with the angle between the adjacent micro-guide vanes 3, for example, this ratio can be 0.9. This structure guides the water flow to smoothly change direction along the groove profile, effectively reducing the flow separation intensity in the leading edge region of the tongue, while the symmetrical arrangement can balance the pressure distribution of the flow field on both sides.

[0052] The design was further optimized by installing a front guide plate 4 near the inlet of the volute body 1 at the tongue. The length of the front guide plate 4 was... D 1 It ranges from 0.8 to 1.0. R The height is 0.8~0.84. R radius of curvature R 3 is 0.36~0.44 R .

[0053] Among them, such as Figure 2 As shown, the height of the front spoiler 4 is H 1 The length of the front spoiler 4 D 1 This is the straight-line distance from the leading edge to the trailing edge of the front guide vane 4, which can be achieved using laser cutting or precision casting. This parameter range balances the guiding effect and flow resistance. The height is the radial extension dimension of the front guide vane 4 within the volute, controlled between 0.8 and 0.84 mm. R Within this range, it can effectively constrain the thickness of the water flow boundary layer. Radius of curvature R 3. The curvature characteristics of the curved surface of the front spoiler 4 are characterized using a value of 0.36~0.44. R Within a certain range, it enables water flow to form a stable boundary layer on the plate surface.

[0054] The above structure enables the establishment of a stable pressure gradient distribution in the tongue region, effectively weakening the dynamic and static interference intensity between the impeller outlet jet and the tongue, reducing broadband noise and pressure pulsation amplitude caused by flow impact, and avoiding the problem of increased hydraulic loss caused by mismatch of guide plate structural parameters.

[0055] Further optimization of the design involves adding a guide hole 7 to the water-facing surface of the front guide plate 4. The radius of the guide hole 7 can be one-hundredth of the base circle radius, i.e., the radius of the guide hole 7. R 2 =0.01 R The number of guide holes 7 is n 1 , n 1 =round ,k =0.8~1.2, round means rounding to the nearest integer. Where, D 1 It is the length of the front spoiler 4. H 1 The height of the front guide vane 4.

[0056] This dimensional design allows for the formation of an effective flow diversion channel while ensuring structural strength. The number of guide holes 7 is the total number of holes opened on the water-facing surface of the front guide plate 4, specifically obtained by multiplying the ratio of the base circle radius to the width of the micro guide vane 3 by pi, then by a proportionality coefficient and rounding down. The guide holes 7 arranged on the water-facing surface of the front guide plate 4 can form multiple micro-jet streams during operation. When the water flow impacts the guide plate, some fluid forms a secondary flow perpendicular to the mainstream direction through the guide holes 7, effectively weakening the boundary layer separation of the mainstream. At the same time, the jets inside the holes exchange momentum with the mainstream in the tongue region, reducing the impact energy of the fluid on the leading edge of the tongue. The micro-jet streams generated by the guide holes 7 can effectively suppress the flow separation phenomenon at the leading edge of the tongue and reduce broadband noise caused by shear layer instability.

[0057] Further optimization of the design: the guide plate on the side away from the inlet of the volute body 1 is the rear guide plate 6. The length of the rear guide plate 6 can be 0.96 to 1.2 times the base circle radius, the height can be 0.96 to 1.04 times the base circle radius, and the radius of curvature can be 0.43 to 0.53 times the base circle radius, forming a radius of curvature ratio of 1.2 times with the front guide plate 4.

[0058] The length of the rear guide vane 6 is its extension along the flow channel direction, and can be achieved using a size range proportional to the base circle radius. Adjusting this parameter can optimize the flow field distribution and reduce local flow losses. The height of the rear guide vane 6 is a dimension perpendicular to the flow channel direction. By limiting its proportional relationship with the base circle radius, flow separation can be effectively avoided. The ratio of the radii of curvature is a matching parameter for the curvature of the front and rear guide vanes 6. For example, the radius of curvature of the rear guide vane 6 can be set to 1.2 times the radius of curvature of the front guide vane 4. This proportional configuration allows for a smooth transition in the streamline curvature changes generated by the two guide vanes, reducing the formation of secondary flows.

[0059] This embodiment extends the flow field control range from the inlet to the end of the baffle by differentiating the curvature ratio of the front and rear guide vanes 6, thus suppressing pressure pulsations while avoiding additional flow losses. Experimental data shows that this structure reduces the turbulent kinetic energy intensity in the latter half of the flow channel by approximately 15% compared to a constant curvature guide vane design. It significantly improves the flow stability in the baffle region, reduces broadband noise caused by flow separation and eddies, and maintains the flow channel efficiency.

[0060] To further optimize the design, the distance between the front guide plate 4 and the rear guide plate 6 in the centrifugal pump volute structure is set to 0.16~0.24 times the base circle radius. The distance between the front guide plate 4 and the rear guide plate 6 is the projected distance between the two guide plates along the axis of the volute body 1. This distance can be achieved by adjusting the installation position of the guide plates or changing their curvature. This distance range balances the flow distribution of water in the tongue region, preventing flow blockage due to too small a distance or secondary flow separation due to too large a distance.

[0061] In some specific implementations, the spacing between the guide vanes can be adjusted according to the base circle radius. For example, when the base circle radius is 100 mm, the spacing between the two guide vanes can be set to 16 mm to 24 mm, and the flow stability can be verified by numerical simulation or experimental testing.

[0062] Through the above technical solution, this application can effectively control the flow separation phenomenon in the tongue region, suppress turbulent noise caused by uneven flow velocity distribution, and avoid energy loss caused by excessive diffusion of water flow between guide plates, thereby improving the operating stability of the centrifugal pump and reducing the noise level.

[0063] Further optimization resulted in the following baffle profile equation: where ξ ranges from 0 to 1, and the origin is the center of the base circle of the volute body 1. Specifically, the baffle profile equation defines the continuous curvature change of the baffle from its starting point to its ending point by varying the parameter ξ within the range of 0 to 1. This equation, with the center of the base circle as the origin, ensures that the geometric center of the baffle coincides with the center of the flow channel of the volute body 1, allowing the water flow to smoothly change direction when passing over the baffle. By adjusting the equation parameters, the curvature distribution of the baffle is designed to naturally match the water flow direction, avoiding local eddies or pressure pulsations caused by abrupt curvature changes. Furthermore, the continuous curvature characteristics defined by the profile equation guide the water flow to form a stable flow structure, suppressing the phenomenon of water flow directly impacting the leading edge of the baffle.

[0064] Further optimization of the scheme, the profile equation of the guide vane is as follows: in, ξ The coordinates range from 0 to 1, with the origin being the center of the base circle of the volute body 1.

[0065] The scheme is further optimized so that the distance between the outlet position of the semi-circular groove 5 and the leading edge of the front guide plate 4 is [missing information]. D 3 , D 3 =0.1~0.14 R。

[0066] In a further optimized design, the cavities 2 are arranged in a rectangular array, with a cylindrical shape and a diameter of [missing information]. D 4 It is 0.014 R Array spacingS 1 It is 0.003 R , S 2 It is 0.003 R。

[0067] Further optimization of the scheme, the number of cavities 2 n 2 The number of guide holes 7 n 1 Satisfying the relation .

[0068] In a further optimized design, the micro-guide plate 3 and the guide plate are made of the same material as the volute body 1, namely 304 stainless steel.

[0069] The embodiments of the present invention have the following technical effects:

[0070] This invention addresses the significant noise problems inherent in traditional volute designs, where fluid instability and interference between moving and stationary components often lead to noise issues without compromising the original performance of the volute. This not only affects equipment operating efficiency but can also negatively impact the surrounding environment and operators. The invention, by precisely adjusting the internal flow channel structure of the volute and optimizing the fluid flow path, reduces eddies and pressure fluctuations, thereby significantly reducing noise from unstable flow and effectively solving the problems of existing technologies. Specifically, the micro-guide vanes 3 arranged at equal angles at the volute inlet effectively divide the water flow, significantly suppressing turbulent separation and velocity pulsation; the semi-circular grooves 5 on the inner wall of the volute reduce shear stress and vortex generation through gentle guidance. Furthermore, the front guide plate 4 with guide holes 7 breaks down the dynamic-static interference between the impeller and the baffle, optimizing the water flow impact angle, while the rear guide plate 6 effectively reduces impact noise by guiding the flow in sections. The Helmholtz resonant cavity array 2 at the tongue can target and absorb periodic pressure pulsations. Combined with the structural synergy of using 304 stainless steel material, this invention achieves broadband noise reduction effect from multiple dimensions such as flow stability, energy dissipation and acoustic resonance.

[0071] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., 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 invention, and are not intended to 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 invention.

[0072] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A centrifugal pump casing with a composite noise reduction structure, characterized in that, Including the base circle radius of R The volute body (1) has a volute chamber inside. Multiple micro-guide plates (3) are distributed circumferentially on the inner side of the inlet of the volute body (1). Two semi-circular grooves (5) are symmetrically arranged along the spiral line on the upstream section of the tongue of the inner wall of the volute body. Two guide plates are provided at the tongue of the volute body (1). The guide plate near the inlet of the volute body (1) is the front guide plate (4), which has several guide holes (7). Several cavities (2) are evenly arranged on the wall surface of the tongue of the volute body (1). The bending direction of the micro-guide plates (3) and the guide plates is consistent with the direction of water flow. The outlet end of the micro-guide plates (3) is rounded with a radius of curvature of 1. R 5 ; Multiple micro-guide vanes (3) are evenly arranged at equal angles at the inlet of the volute, with the included angle between two adjacent micro-guide vanes (3) being... α The height of the micro-guide plate (3) is 55°~60°. H 3 It is 0.2~0.3 R ,width D 5 The value is 0.05~0.

08. R The number of micro-guide plates (3) is n , n for , round This indicates rounding to the nearest integer. The outlet tangent of the micro-guide plate (3) forms a guide angle of 15°~20° with the inner wall tangent of the volute body (1). γ The profile equation of the micro-guide plate (3) is: ， in, The coordinates are 0~1, and the origin is the center of the base circle of the volute body (1). R 5 The radius of the rounded corner at the outlet end of the micro-guide plate (3) is given.

2. The centrifugal pump casing with a composite noise reduction structure according to claim 1, characterized in that, The radius of the semi-circular groove (5) R 1 It is 0.006 R The angles at the inlet and outlet ends of the semi-circular groove (5) β It is 0.9 α .

3. The centrifugal pump casing with a composite noise reduction structure according to claim 1, characterized in that, The front guide plate (4) has guide holes (7) on its water-facing surface, with a radius of... R 2 It is 0.01 R The number of guide holes (7) is , , k =0.8~1.2, round means rounding to the nearest integer. D 1 It is the length of the front spoiler (4). H 1 The height of the front guide vane (4) is given.

4. The centrifugal pump casing with a composite noise reduction structure according to claim 3, characterized in that, The length of the front guide plate (4) D 1 It ranges from 0.8 to 1.

0. R The height is 0.8~0.

84. R radius of curvature R 3 The value is 0.36~0.

44. R The guide plate on the side away from the inlet of the volute body (1) is the rear guide plate (6), and the length of the rear guide plate (6) is... D 2 The value is 0.96~1.

2. R ,high H 2 The value ranges from 0.96 to 1.

04. R radius of curvature R 4 The value is 0.43~0.

53. R The front guide vane (4) and the rear guide vane (6) form a radius of curvature ratio of 1.2; the distance between the front guide vane (4) and the rear guide vane (6) is... D , D =0.16~0.24 R .

5. The centrifugal pump casing with a composite noise reduction structure according to claim 1, characterized in that, The profile equation of the guide vane is: in, ξ The coordinates are 0~1, and the origin is the center of the base circle of the volute body (1).

6. The centrifugal pump casing with a composite noise reduction structure according to claim 1, characterized in that, The distance from the outlet of the semi-circular groove (5) to the leading edge of the front guide plate (4) is... D 3 , D 3 =0.1~0.14 R .

7. The centrifugal pump casing with a composite noise reduction structure according to claim 1, characterized in that, The cavities (2) are arranged in a rectangular array and are cylindrical in shape with a diameter of D 4 It is 0.014 R Array spacing S 1 It is 0.003 R , S 2 It is 0.003 R .

8. The centrifugal pump casing with a composite noise reduction structure according to claim 7, characterized in that, The number of cavities (2) n 2 The number of guide holes (7) n 1 Satisfying the relation .

Images