Variable-curvature arc noise reduction volute structure

Abstract

The invention discloses a variable-curvature arc noise reduction volute structure, and relates to the technical field of new energy automobile air conditioners. Comprising a volute shell, a variable-curvature arc-shaped structure and an efficiency ring. The volute shell is provided with an air inlet and an air outlet, and a volute flow channel is formed in the volute shell; the variable-curvature arc-shaped structure is arranged on the inner wall of the volute shell, the curvature radius of the variable-curvature arc-shaped structure gradually changes in the air flowing direction, and the variable-curvature arc-shaped structure is used for guiding air flow to flow stably The efficiency ring is arranged at the air inlet part, is of an annular structure and is used for restraining airflow entering the volute runner and restraining airflow separation. Through the composite design of the variable-curvature arc-shaped structure and the efficiency ring, the air flowing state of the impeller volute area is optimized, on the premise that the air supply amount is not reduced, the pneumatic noise is reduced, the structure is simple, the method is compatible with an existing injection molding process, and the method is particularly suitable for a new energy automobile air conditioning system.

Description

Technical Field

[0001] This invention relates to the field of air conditioning technology for new energy vehicles, and in particular to a variable curvature arc-shaped noise-reducing volute structure, which is suitable for the optimized design of the volute of an automotive air conditioning blower. It can effectively improve the aerodynamic noise in the impeller volute area and enhance driver and passenger comfort while ensuring the air volume of the air conditioner. Background Technology

[0002] The automotive air conditioning system is an important component of modern automobiles, and its air delivery function relies on a blower for power. The blower's motor outputs mechanical energy, driving the impeller to rotate. When the impeller does work on the air, it converts mechanical energy into the air's kinetic and pressure energy. The kinetic energy propels the air along the flow channel, and the pressure energy pressurizes the air, ultimately completing the air delivery and meeting the basic requirement of the air conditioning system to deliver air into the vehicle.

[0003] During the operation of a blower, the flow channel formed by the impeller and volute is the core area of ​​airflow and the main source of aerodynamic noise. From a flow characteristic perspective, the air velocity is highest near the impeller and volute structure. The impeller rotation directly drives air acceleration, and because the volute flow channel transitions from a circular to a diffused shape, and there is dynamic-static interference between the impeller and volute, this region easily forms turbulent and vortex zones. The irregular movement of air particles in turbulence, and the generation and breakdown of vortices, cause flow field disturbances, which are directly converted into aerodynamic noise.

[0004] From the perspective of driver and passenger experience, this type of noise is a key factor affecting in-vehicle comfort. Prolonged exposure to air conditioning noise can easily lead to auditory fatigue, distraction, and even reduced driving safety. Therefore, reducing noise in the impeller and volute area while ensuring sufficient airflow is a core requirement of automotive air conditioning design. This requirement is particularly prominent in the field of new energy vehicles, as these vehicles lack the masking effect of engine noise, making air conditioning noise even more noticeable.

[0005] Current optimizations for noise reduction in blower housings mostly focus on single structural adjustments, which have significant limitations. For example, CN215566921U discloses a noise reduction structure for an automotive air conditioning blower, which absorbs noise by wrapping the casing with sound-absorbing cotton. However, this increases the weight and cost of the casing, and the material is prone to falling off due to long-term airflow impact, affecting the stability of the air conditioning system. CN203430870U discloses a noise reduction structure with a baffle at the air inlet of the blower housing, but a single baffle structure cannot effectively solve the turbulence problem inside the casing. CN217207041U discloses a structure with noise-reducing blocks on the outer surface of the blower housing, which mainly targets surface vibration noise reduction, but has limited effect on improving aerodynamic noise inside the casing.

[0006] The shortcomings of existing technologies are mainly reflected in the following aspects: if only the size of the volute flow channel is optimized, the air velocity may decrease due to excessive expansion of the flow channel, thereby reducing the air supply volume; if only sound-absorbing materials are added to reduce noise, the weight and cost of the volute will increase; if only local structures such as the inlet radius are adjusted, it is difficult to comprehensively improve the airflow state of the entire volute flow channel. Therefore, it is urgent to develop a composite noise reduction structure that can optimize the airflow state inside the volute as a whole. Summary of the Invention

[0007] The purpose of this invention is to provide a variable curvature arc-shaped noise reduction volute structure. By combining the variable curvature arc structure with the efficiency ring, the airflow state in the impeller volute area is optimized, and aerodynamic noise is effectively improved without reducing the air volume, thus overcoming the limitations of existing single-structure optimization of volutes.

[0008] To achieve the above objectives, the present invention provides a variable curvature arc-shaped noise reduction volute structure, comprising: a volute shell having an air inlet and an air outlet, wherein an airflow channel for airflow is formed inside the volute shell; a variable curvature arc-shaped structure disposed on the inner wall of the volute shell, wherein the radius of curvature of the variable curvature arc-shaped structure is gradually changed along the airflow direction to guide the airflow to flow smoothly and reduce turbulence; and an efficiency ring disposed at the air inlet of the volute shell, wherein the efficiency ring has an annular structure to constrain the airflow entering the volute channel and suppress airflow separation.

[0009] In a preferred embodiment of the present invention, the radius of curvature of the variable curvature arc structure gradually increases along the airflow direction, with the radius of curvature of the inlet section being smaller than that of the outlet section. The radius of curvature of the inlet section is designed to adapt to the high-speed airflow at the impeller outlet, while the radius of curvature of the outlet section is designed to guide the smooth diffusion of the airflow. This gradual curvature design is based on the Dean number De=Re. Based on the principles of fluid dynamics, where Re is the Reynolds number, rc is the characteristic radius of the flow channel, and R is the radius of curvature of the flow channel centerline, the relative relationship between the centrifugal force and viscous force of the airflow is optimized by controlling the curvature change, thereby reducing secondary flow and turbulence generation.

[0010] As a preferred embodiment of the present invention, the thickness of the variable curvature arc-shaped structure is 3mm to 13mm. According to the flow continuity equation v=Q / A, where v is the wind speed, Q is the air volume, and A is the internal cross-sectional area of ​​the volute, with a constant air volume, a smaller internal cross-sectional area of ​​the volute (i.e., a larger arc-shaped structure thickness) results in higher wind speeds, more severe turbulence, and greater noise. Therefore, the thickness of the arc-shaped structure needs to strike a balance between air guiding effect and flow channel cross-sectional area. The present invention, through CFD simulation optimization, determined the optimal thickness range of 3mm to 13mm.

[0011] As a preferred embodiment of the present invention, the gap between the variable curvature arc structure and the blower impeller is greater than 4mm. Maintaining an appropriate gap can avoid dynamic and static interference between the impeller and the arc structure, and reduce airflow compression and increased noise caused by an excessively small gap.

[0012] As a preferred embodiment of the present invention, the efficiency ring is disposed on the outer side and / or inner side of the air inlet. The efficiency ring can be flexibly arranged according to actual noise reduction requirements. Disposing it on the outer side of the air inlet can pre-constrain the airflow entering the volute, while disposing it on the inner side of the air inlet can further stabilize the airflow that has already entered the volute.

[0013] In a preferred embodiment of the present invention, the number of efficiency rings is one or more, and the plurality of efficiency rings are arranged sequentially along the axial direction of the air inlet. The plurality of efficiency rings can form multi-level airflow constraints, gradually stabilizing the airflow and further improving the noise reduction effect.

[0014] In a preferred embodiment of the present invention, the radius of the efficiency ring is greater than or equal to the radius of the air inlet. According to the fluid resistance formula F... D =½ρv 2 AC D F D Where ρ is the fluid resistance, ρ is the fluid density, v is the airflow velocity, A is the characteristic area of ​​the efficiency ring, and C is the fluid resistance. D As the drag coefficient, the radius of the efficiency ring is matched with the inner and outer diameters of the impeller, which can effectively constrain the airflow without increasing too much flow resistance.

[0015] In a preferred embodiment of the present invention, the ring width of the efficiency ring is 1 / 8 to 1 / 4 of the radius of the volute shell. The ring width is the axial dimension of the efficiency ring. An appropriate ring width can form an effective turbulence constraint zone. If the ring width is too small, the constraint effect will not be obvious, and if the ring width is too large, it will increase the flow resistance.

[0016] As a preferred embodiment of the present invention, the efficiency ring has a length of either a full circle or a partial arc segment. The efficiency ring can be customized based on the turbulence concentration region determined by CFD simulation results. A full-circumference efficiency ring provides airflow constraint in the entire circumference, while a partial arc segment efficiency ring is optimized for turbulence regions in a specific orientation.

[0017] As a preferred embodiment of the present invention, the variable curvature arc structure and the efficiency ring are integrally formed with the volute housing. This integrated design is achieved through injection molding, eliminating assembly gaps and avoiding secondary airflow disturbances caused by gaps, further reducing potential noise sources. It also simplifies the assembly process and reduces manufacturing costs.

[0018] In a preferred embodiment of the present invention, the volute housing includes an upper volute housing and a lower volute housing, which are fixed together to form the volute flow channel. The efficiency ring is disposed on the upper volute housing, and the variable curvature arc structure is disposed on the inner wall of the lower volute housing. This split housing design facilitates the installation and maintenance of the blower. Furthermore, by separately placing the efficiency ring and the variable curvature arc structure on the upper and lower housings, their synergistic noise reduction effect can be better utilized.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) Significant noise reduction effect: The variable curvature arc structure guides the airflow through the gradual curvature, reducing the generation of turbulence and eddies; the efficiency ring constrains the separation of inlet and outlet airflow, forming a turbulence constraint zone, which reduces the aerodynamic noise of the air conditioner by 3-5dB at low speed, effectively improving the comfort of drivers and passengers.

[0020] (2) Stable air volume: The variable curvature design avoids local expansion of the flow channel and causes vortices. The height of the efficiency ring is matched and does not obstruct the main airflow. The measured air volume is reduced by no more than 1% compared with the traditional volute, which meets the air volume performance requirements of air conditioning.

[0021] (3) Simple and easy to implement: No additional sound-absorbing components are required. Noise reduction is achieved through the optimization of the volute structure itself. It is compatible with existing injection molding processes. Material costs and production costs are reduced to a certain extent, making it suitable for mass production.

[0022] (4) Advantages of integrated design: The variable curvature arc structure and efficiency ring are integrally formed with the volute shell, with no assembly gap, avoiding secondary airflow disturbance and further improving the noise reduction effect.

[0023] (5) Wide range of applications: This invention is particularly applicable to air conditioning systems of new energy vehicles, and can significantly improve the quietness of the vehicle interior in environments where engine noise is not masked. Attached Figure Description

[0024] Figure 1 This is an exploded view of the air conditioning blower module structure used in the variable curvature arc-shaped noise reduction volute structure of the present invention. Figure 2 This is a schematic diagram showing the position and shape of the efficiency ring on the outer side of the air inlet of the volute according to the present invention; Figure 3 This is a schematic diagram showing the shape of the efficiency ring of the present invention at two positions inside the air inlet of the volute. Figure 4 This is a schematic diagram showing the position and shape of the variable curvature arc structure of the present invention inside the volute; Figure 5 Comparison of measured noise levels of the air conditioner before and after adding an efficiency loop and a variable curvature arc structure to the air conditioner blower module; Figure 6 Comparison of noise distribution cloud maps (greater than 90 dB) before and after adding an efficiency loop and a variable curvature arc structure to the air conditioning blower module, based on CFD analysis.

[0025] In the diagram: 101 - blower; 102 - lower casing of volute; 103 - upper casing of volute; 201 - first efficiency ring; 301 - second efficiency ring; 302 - third efficiency ring; 401 - variable curvature arc structure. Detailed Implementation

[0026] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. 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.

[0027] In the description of this invention, it should be understood that the terms "upper", "lower", "inner", "outer", "axial", "radial", "circumferential", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing this invention 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. Therefore, they should not be construed as limitations on this invention.

[0028] Example 1 Please see Figures 1 to 4 This embodiment provides a variable curvature arc-shaped noise reduction volute structure, including a volute shell, a variable curvature arc structure 401, and an efficiency ring.

[0029] like Figure 1 As shown, this embodiment is applied to an automotive air conditioning blower module. The air conditioning blower module consists of a blower 101, a lower volute housing 102, and an upper volute housing 103. The lower volute housing 102 and the upper volute housing 103 are fixed to each other to form the volute housing, and an airflow channel is formed inside the volute housing for air flow. The volute housing has an air inlet and an air outlet. The air inlet is located on one side of the upper volute housing 103, and the air outlet is located in the tangential direction of the volute housing. The blower 101 is mounted on the lower volute housing 102, and the impeller of the blower 101 is located inside the volute flow channel.

[0030] like Figure 4As shown, a variable curvature arc structure 401 is disposed on the inner wall of the lower casing 102 of the volute. The radius of curvature of the variable curvature arc structure 401 is gradually set along the airflow direction, specifically, the radius of curvature is smaller in the inlet section and gradually increases from the middle section to the outlet section. The small radius of curvature in the inlet section is designed to adapt to the high-speed airflow at the impeller outlet, so that the airflow can smoothly transition from the impeller outlet to the volute flow channel; the large radius of curvature in the outlet section is designed to guide the airflow to diffuse smoothly and avoid vortices caused by abrupt changes in the flow channel.

[0031] In this embodiment, the design of the variable curvature arc structure 401 is based on the Dean number De=Re. The fluid dynamics principle is used. By controlling the gradual change of the radius of curvature R, the relative relationship between the centrifugal force and viscous force of the airflow is optimized, reducing secondary flow and turbulence generation. The thickness of the variable curvature arc structure 401 is 8mm, which is within the preferred range of 3mm to 13mm. The gap between the variable curvature arc structure 401 and the impeller of the blower 101 is 5mm, which is greater than the minimum gap requirement of 4mm, to avoid dynamic and static interference between the impeller and the arc structure.

[0032] like Figure 2 and Figure 3 As shown, the efficiency ring is disposed at the air inlet of the upper housing 103 of the volute. In this embodiment, three efficiency rings are provided, namely a first efficiency ring 201, a second efficiency ring 301, and a third efficiency ring 302. The first efficiency ring 201 is located on the outer side of the air inlet, and the second efficiency ring 301 and the third efficiency ring 302 are located on the inner side of the air inlet, arranged sequentially along the axial direction of the air inlet.

[0033] The efficiency loop design is based on the fluid resistance formula F D =½ρv 2 AC D The radius of the efficiency ring is slightly larger than the radius of the air inlet, matching the inner and outer diameters of the blower impeller 101. The ring width of the efficiency ring is 1 / 6 of the volute casing radius, preferably within the range of 1 / 8 to 1 / 4. The first efficiency ring 201 is a full-circle structure, while the second efficiency ring 301 and the third efficiency ring 302 are designed as partially arc-shaped structures based on the turbulence concentration regions determined by CFD simulation results.

[0034] When airflow passes through the efficiency ring, a turbulence constraint zone is formed, reducing airflow separation at the outlet and suppressing resonance noise. The variable curvature arc structure 401 works in conjunction with the efficiency ring to ensure that airflow through the efficiency ring and the variable curvature arc structure 401 improves airflow turbulence, thereby reducing the overall sound pressure level and optimizing order noise.

[0035] In this embodiment, the variable curvature arc structure 401 and the efficiency ring are integrally molded with the volute housing, manufactured through injection molding. This integrated design eliminates assembly gaps, avoiding secondary airflow disturbances caused by gaps and further reducing potential noise sources.

[0036] Example 2 This embodiment provides an automotive air conditioning blower module, including a blower 101 and the variable curvature arc-shaped noise reduction volute structure described in Embodiment 1. The blower 101 is a centrifugal blower, installed inside the volute housing. The impeller of the blower 101 is located inside the volute flow channel, and the outer diameter of the impeller matches the radius of the efficiency ring.

[0037] Working principle: When the blower 101 is working, the motor drives the impeller to rotate, and the impeller does work on the air, converting mechanical energy into the kinetic and pressure energy of the air. Air is drawn into the volute flow channel from the air inlet of the upper casing 103.

[0038] When air enters the volute, it first passes through the outer constraint of the first efficiency ring 201, forming an orderly inflow. Subsequently, the airflow continues to pass through the second efficiency ring 301 and the third efficiency ring 302, forming a multi-stage turbulence constraint zone, further stabilizing the airflow state and reducing airflow separation.

[0039] Once stabilized, the airflow flows along the volute channel under the centrifugal force generated by the impeller's rotation. When the airflow passes through the variable curvature arc structure 401, the gradual curvature of the arc structure guides the airflow through a smooth transition. The small radius of curvature in the inlet section adapts to the high-speed airflow at the impeller outlet, while the large radius of curvature in the outlet section guides the airflow to diffuse smoothly. This design avoids vortices caused by abrupt changes in the flow channel, reduces turbulent kinetic energy, and suppresses specific order noise.

[0040] Finally, the air, after being guided and stabilized, is discharged from the volute outlet and enters the subsequent air duct system of the car's air conditioning system.

[0041] Noise reduction effect verification: like Figure 5 As shown, the measured noise data of the air conditioner were compared before and after adding an efficiency ring and a variable curvature arc structure to the air conditioner blower module. The test results show that, at all speeds, the aerodynamic noise of the air conditioner is significantly reduced after adopting the variable curvature arc noise reduction volute structure of this invention, with a noise reduction of 3-5 dB at low speeds.

[0042] like Figure 6 As shown in the figure, the distribution cloud map comparison of noise greater than 90dB in CFD analysis shows that after adding the efficiency ring and the variable curvature arc structure, the noise source greater than 90dB in the volute is significantly reduced, and the area of ​​the high noise region is greatly reduced. This fully verifies that the composite design of the present invention can effectively optimize the airflow state in the impeller volute region and achieve effective improvement of aerodynamic noise.

[0043] Meanwhile, the measured air volume decreased by no more than 1% compared with the traditional volute, meeting the air volume performance requirements of air conditioning, proving that the present invention maintains good air delivery performance while reducing noise.

[0044] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Contents not described in detail in this specification belong to prior art known to those skilled in the art.

Claims

1. A variable curvature arc-shaped noise-reducing volute structure, characterized in that, include: The volute housing has an air inlet and an air outlet, and an airflow channel is formed inside the volute housing for air flow. A variable curvature arc structure is provided on the inner wall of the volute shell. The radius of curvature of the variable curvature arc structure is gradually set along the air flow direction to guide the airflow to flow smoothly and reduce turbulence. An efficiency ring is disposed at the air inlet of the volute housing. The efficiency ring has a ring structure and is used to constrain the airflow entering the volute flow channel and suppress airflow separation.

2. The variable curvature arc-shaped noise-reducing volute structure according to claim 1, characterized in that, The radius of curvature of the variable curvature arc structure gradually increases along the airflow direction, with the radius of curvature of the inlet section being smaller than that of the outlet section; the radius of curvature of the inlet section is designed to adapt to the high-speed airflow at the impeller outlet, and the radius of curvature of the outlet section is designed to guide the airflow to diffuse smoothly.

3. The variable curvature arc-shaped noise-reducing volute structure according to claim 1, characterized in that, The thickness of the variable curvature arc structure is 3 mm to 13 mm.

4. The variable curvature arc-shaped noise-reducing volute structure according to claim 1, characterized in that, The gap between the variable curvature arc structure and the blower impeller is greater than 4mm.

5. The variable curvature arc-shaped noise-reducing volute structure according to claim 1, characterized in that, The efficiency ring is located on the outer and / or inner side of the air inlet.

6. The variable curvature arc-shaped noise-reducing volute structure according to claim 1, characterized in that, The number of efficiency rings is one or more, and the multiple efficiency rings are arranged sequentially along the axial direction of the air inlet.

7. The variable curvature arc-shaped noise-reducing volute structure according to claim 1, characterized in that, The radius of the efficiency ring is greater than or equal to the radius of the air inlet; the ring width of the efficiency ring is 1 / 8 to 1 / 4 of the radius of the volute casing.

8. The variable curvature arc-shaped noise-reducing volute structure according to claim 1, characterized in that, The efficiency loop has a length of either a full circle or a partial arc segment.

9. The variable curvature arc-shaped noise-reducing volute structure according to any one of claims 1-8, characterized in that, The variable curvature arc structure and the efficiency ring are integrally formed with the volute shell.

10. The variable curvature arc-shaped noise-reducing volute structure according to claim 9, characterized in that, The volute housing includes an upper volute housing and a lower volute housing, which are fixed to each other to form the volute flow channel. The efficiency ring is disposed on the upper volute housing, and the variable curvature arc structure is disposed on the inner wall of the lower volute housing.

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