An integrated dual-source locomotive braking resistor fan

Abstract

This invention discloses an integrated dual-source locomotive braking resistor fan, belonging to the field of rail transit equipment, comprising an inlet duct, an outlet duct, and an impeller. Multiple front guide vanes are arranged circumferentially inside the inlet duct. Multiple rear guide vanes are arranged circumferentially inside the outlet duct. The impeller is located between the inlet and outlet ducts, and has multiple blades arranged circumferentially. Through the three-stage airflow organization structure of the front guide vanes, impeller, and rear guide vanes, the air entering the fan is pre-swirled, pressurized, and rectified. Specifically, the front guide vanes guide the incoming flow direction before the air enters the impeller, allowing the airflow to enter the impeller area in a more stable and orderly state, thereby reducing inlet turbulence and impact losses. After the impeller completes the main energy conversion, the rear guide vanes further diffuse and rectify the rotating airflow, reducing the rotational component in the wake, making the airflow field more stable, and reducing outlet pulsation and secondary airflow disturbance.

Description

Technical Field

[0001] This invention belongs to the field of rail transit equipment, specifically an integrated dual-source locomotive braking resistor fan. Background Technology

[0002] In the field of rail transit locomotives, brake resistor fans are mainly used to provide forced cooling for brake resistor devices, ensuring that the brake resistors can operate continuously and stably under electric braking conditions. Existing locomotive brake resistor fans typically consist of a DC motor, impeller, and fan casing, with a relatively simple overall structure. Their design focuses primarily on meeting basic ventilation and heat dissipation requirements, while paying insufficient attention to noise and vibration control during fan operation.

[0003] In existing technologies, fan systems mostly employ standardized impellers and conventional duct structures for flow channel design. The impeller blade profile, number of blades, installation angle, and internal airflow guiding structure of the duct are all relatively traditional. During high-speed operation, strong turbulence and airflow separation easily occur at the impeller inlet, blade tip gap, and inside the duct, resulting in significant aerodynamic noise. Simultaneously, periodic pressure pulsations are easily generated during impeller rotation, further increasing fan system vibration and leading to structural resonance, abnormal casing noise, and fatigue of connecting components. Summary of the Invention

[0004] The purpose of this invention is to provide an integrated dual-source locomotive braking resistor fan to solve the problems mentioned in the prior art.

[0005] An integrated dual-source locomotive braking resistor fan is provided, comprising: The air inlet duct has multiple guide vanes arranged circumferentially inside; The air outlet duct has multiple rear guide vanes arranged circumferentially inside. An impeller is located between the air inlet and the air outlet. The impeller has multiple blades arranged circumferentially. The airfoil section of the blade has two flanges on the side closest to the pressure surface, and the two flanges have a common tangent. The common tangent forms an installation angle α with the radial plane of the impeller. In the direction of the blade's extension from the root to the tip, the blade's installation angle gradually transitions from α1 to α2, with α1 being 43.3°-44.3° and α2 being 27.3°-28.3°.

[0006] As a further embodiment of the present invention: α1 is 43.3°-43.8°, and α2 is 27.3°-27.8°.

[0007] As a further embodiment of the present invention: α1 is 43.8°-44.3°, and α2 is 27.8°-28.3°.

[0008] As a further aspect of the present invention: α1 is 43.8° and α2 is 27.8°.

[0009] As a further aspect of the present invention: the leading vane is an arc-shaped plate structure, and the arc radius of the leading vane is R310-R315.

[0010] As a further aspect of the present invention: the two endpoints of the airfoil section near the convex side form two tangents respectively, the two tangents form an aspect angle β1, and the β1 angle is 18.5°-19.5°.

[0011] As a further aspect of the present invention: the two endpoints of the airfoil section of the leading blade near the concave side form a line, and the line forms an installation angle γ1 with the radial plane of the impeller, and the angle γ1 is 80°-81°.

[0012] As a further aspect of the present invention: the rear guide vane is an arc-shaped plate structure with an arc radius of 166°-168°.

[0013] As a further aspect of the present invention: the two endpoints of the airfoil section near the convex side of the rear guide vane form two tangents respectively, and the two tangents form an aspect angle β2, with the β2 angle being 38°-39°.

[0014] As a further aspect of the present invention: the two endpoints of the airfoil section of the rear guide vane near the concave side form a line, and the line forms an installation angle γ2 with the radial plane of the impeller, and the angle γ2 is 73°-74°.

[0015] As a further aspect of the present invention: the distance between the outer diameter of the blade and the inner wall of the outer cylinder of the air inlet is 2mm-5mm, and the distance between the outer diameter of the blade and the inner wall of the outer cylinder of the air outlet is 2mm-5mm.

[0016] As a further aspect of the present invention: there is a gap of 16mm-18mm between the impeller and the opposite end face of the air inlet, and a gap of 9mm-11mm between the impeller and the opposite end face of the air outlet.

[0017] As a further aspect of the present invention, the ratio of the number of the leading vane, the blade, and the trailing vane is 12:13:19.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. Through a three-stage airflow organization structure consisting of the front guide vanes, impeller, and rear guide vanes, the air entering the fan is pre-swirled, pressurized, and rectified. Specifically, the front guide vanes guide the incoming airflow direction before it enters the impeller, allowing the airflow to enter the impeller area in a more stable and orderly state, thereby reducing inlet turbulence and impact losses. After the impeller completes the main energy conversion, the rear guide vanes further diffuse and rectify the rotating airflow, reducing the rotational component in the wake, making the airflow field more stable, and reducing outlet pulsation and secondary airflow disturbances.

[0019] 2. The installation angle α formed between the common tangent and the radial plane of the impeller determines the angle of attack of the blades on the airflow, so that the blades can provide sufficient pressure lift while avoiding stall noise caused by excessive angle of attack.

[0020] 3. As the blade extends from the root to the tip, the installation angle gradually transitions from α1 to α2. Since the linear velocity at the blade tip is much higher than at the blade root during impeller rotation, using the same installation angle at all locations can easily lead to an excessively large relative angle of attack in the blade tip region, causing flow separation and strong vortices. This design combines a larger installation angle at the root with a smaller installation angle at the tip, making the relative airflow angle of attack at different radii of the blade more consistent, thereby improving the aerodynamic consistency along the entire blade height. This design effectively reduces tip vortices, decreases airflow pulsation, and improves vibration and noise issues during fan operation, while also increasing the overall wind pressure and efficiency of the fan. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this drawing or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this drawing. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0022] Figure 1 Cross-sectional view of the integrated structure of the dual-source locomotive braking resistor fan; Figure 2 This is a structural arrangement diagram of the blades of the present invention; Figure 3 This is a structural layout diagram of the air inlet duct of the present invention; Figure 4 This is a structural layout diagram of the air outlet duct of the present invention; Figure 5 This is a cloud diagram showing the axial flow field distribution of the fan of the present invention; Figure 6 This is a cloud map showing the axial velocity distribution of the fan of the present invention; Figure 7 This is a cloud map showing the axial pressure distribution of the fan of the present invention.

[0023] In the diagram: 1. Air inlet; 11. Front guide vane; 2. Air outlet; 21. Rear guide vane; 3. Impeller; 31. Blade. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this application clearer, the application is described and illustrated below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application. All other embodiments obtained by those skilled in the art based on the embodiments provided in this application without inventive effort are within the scope of protection of this application.

[0025] Obviously, the accompanying drawings described below are merely some examples or embodiments of this application. Those skilled in the art can apply this application to other similar scenarios based on these drawings without any inventive effort. Furthermore, it is understood that although the efforts made in this development process may be complex and lengthy, for those skilled in the art related to the content disclosed in this application, any changes to design, manufacturing, or production based on the technical content disclosed in this application are merely conventional technical means and should not be construed as insufficient disclosure of the content of this application.

[0026] However, there may be instances where unnecessary detailed descriptions are omitted. For example, detailed descriptions of well-known matters or repetitive descriptions of essentially the same structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand this application and are not intended to limit the subject matter of the claims.

[0027] Please see Figures 1-2 As shown in the figure, in this embodiment of the invention, an integrated dual-source locomotive braking resistor fan includes an inlet duct 1, an outlet duct 2, and an impeller 3. Multiple front guide vanes 11 are arranged circumferentially inside the inlet duct 1. Multiple rear guide vanes 21 are arranged circumferentially inside the outlet duct 2. The impeller 3 is disposed between the inlet duct 1 and the outlet duct 2, and the impeller 3 has multiple blades 31 arranged circumferentially.

[0028] Specifically, the overall structure of the fan is arranged axially along the airflow direction, consisting of an inlet duct 1, an impeller 3, and an outlet duct 2. This creates a three-stage airflow organization structure: the front guide vane 11 pre-swirls to guide the flow, the blades 31 pressurize and perform work, and the rear guide vane 21 rectifies and diffuses the flow. Compared to traditional fan structures that rely solely on the impeller for air intake and exhaust, this design actively intervenes in the flow field before and after the impeller 3 using the front and rear guide vanes. This ensures that the airflow maintains good flow stability both before and after entering the impeller, thereby reducing airflow turbulence, pressure pulsation, and aerodynamic noise.

[0029] Furthermore, firstly, since the impeller 3 is in a high-speed rotating state, if the air directly impacts the leading edge of the blade 31, it is easy to form a large impact loss and local pressure change in the inlet area of ​​the blade 31, which in turn induces boundary layer separation, airflow separation and high-frequency noise.

[0030] Therefore, when multiple guide vanes 11 are evenly arranged around the circumference of the air inlet duct 1, they can form an annular guide array in front of the impeller 3 inlet. When air enters the air inlet duct 1, the guide vanes 11 can pre-adjust the airflow direction, so that the air no longer enters the impeller 3 directly in a completely axial or disordered state, but forms a pre-swirling airflow with a certain direction.

[0031] The pre-swirling airflow formed by the leading blade 11 can make the airflow direction closer to the inlet direction of the blade 31, thereby reducing the airflow impact at the leading edge of the blade 31 and allowing the air to flow more smoothly along the surface of the blade 31, thereby reducing inlet turbulence and the passing frequency noise of the blade 31.

[0032] Secondly, since the air output by impeller 3 has not only axial velocity but also a strong rotational component, if it is discharged directly, it is easy to form a strong wake vortex and unstable pulsating airflow in the outlet area, which in turn leads to increased vibration of the fan casing and aerodynamic noise.

[0033] Therefore, the rear guide vane 21 rectifyes and reduces the swirl of the airflow at the impeller 3 outlet through a fixed guide structure, gradually restoring the rotating airflow to a more stable axial flow. While reducing the intensity of the wake rotation, the rear guide vane 21 also diffuses the high-speed airflow, converting some kinetic energy into static pressure and improving the overall wind pressure utilization rate of the fan.

[0034] Furthermore, since there are significant differences in the circumferential velocity at different radii of the blade 31, with a lower linear velocity at the blade root and a higher linear velocity at the blade tip, if the entire blade 31 adopts a uniform installation angle, the blade tip area is prone to forming an excessively large relative angle of attack, causing severe airflow separation and blade tip leakage vortex near the blade tip, resulting in a decrease in fan efficiency and an increase in sharp whistling noise.

[0035] Therefore, the airfoil section of blade 31 has two flanges on the side near the pressure surface, and the two flanges have a common tangent. The common tangent forms an installation angle α with the radial plane of impeller 3. In the extension direction of blade 31 from root to tip, the installation angle of blade 31 gradually transitions from α1 to α2, with α1 being 43.3°-44.3° and α2 being 27.3°-28.3°.

[0036] This design employs a gradual change in the installation angle of blade 31 along the blade height direction, creating a twisted structure from the root to the tip. A larger installation angle is used at the root, while a smaller angle is used at the tip. This structure effectively compensates for differences in relative airflow velocity at different radii, allowing different regions of blade 31 to achieve a closer approximation of the actual angle of attack, thereby improving aerodynamic consistency throughout the blade height direction.

[0037] Furthermore, α1 is controlled within the range of 43.3°-44.3° to ensure sufficient pressure rise in the blade root region. However, due to the higher circumferential velocity in the blade tip region, using a larger installation angle would lead to increased airflow impact and blade tip stall. Therefore, the blade tip installation angle is reduced to 27.3°-28.3°, allowing the airflow in the blade tip region to flow more smoothly over the blade 31 surface, thereby reducing blade tip vortices and aerodynamic noise. This twisted blade 31 structure not only improves the overall efficiency of the impeller 3 but also reduces the load difference between different areas of the blade 31, lowering the periodic excitation force generated during rotation, thus mitigating wind turbine vibration.

[0038] It should be noted that the blade 31 in this patent is a three-dimensional twisted blade 31, meaning that the installation angle changes continuously from the blade root to the blade tip. Therefore, the cross-sectional shape and orientation of the blade 31 at different height positions are not actually completely the same. The airfoil cross-section of the blade 31 referred to in this invention is obtained by taking the rotation axis of the impeller 3 as the center, and at a certain radius position of the blade 31, intersecting the blade 31 with a cylindrical surface extending parallel to the axis of the impeller 3, and then unfolding this intersection line onto a plane to obtain the airfoil cross-section at that radius position.

[0039] It should be further noted that the pressure surface of the airfoil section referred to in this invention is relative to the suction surface. When air flows through the airfoil of blade 31, the side with higher pressure is called the pressure surface, and the side with lower pressure is called the suction surface. Specifically, the pressure surface is the concave side of blade 31, and the suction surface is the convex side of blade 31.

[0040] Preferably, in the direction of extension of the blade 31 from the root to the tip, the installation angle of the blade 31 gradually transitions from α1 to α2, and α1 is 43.8° and α2 is 27.8°.

[0041] In some embodiments, please refer to Figure 1 and Figure 3 As shown, the guide vane 11 has an arc-shaped plate structure with an arc radius of R310-R315. The arc-shaped plate structure allows the air entering the fan to smoothly turn along the curved surface of the guide vane 11. Compared with straight guide vanes or zigzag guide vanes, it causes less disturbance to the airflow and can reduce boundary layer separation in the inlet area.

[0042] Limiting the arc radius to a specific range means that the guide vane 11 optimizes the degree of airflow deflection. If the arc radius is too small, the airflow turns too sharply, easily causing localized flow separation and boundary layer separation; while if the arc radius is too large, the guiding effect weakens, making it impossible to effectively establish a pre-swirling flow field. This scheme limits the arc radius to R310-R315, enabling the guide vane 11 to provide stable guidance while avoiding excessive disturbance, thereby reducing airflow impact noise at the impeller 3 inlet, improving impeller intake uniformity, and mitigating vibration problems caused by inlet turbulence.

[0043] The airfoil section of the leading blade 11 has two tangents formed at its two endpoints near the convex side, which together form an aspect ratio β1 of 18.5°–19.5°. This aspect ratio controls the diffusion of airflow through the leading blade 11. An appropriate aspect ratio allows for a more uniform velocity distribution of the airflow after passing through the leading blade 11, mitigating the problem of localized high-speed airflow impacting the blade 31. If the aspect ratio is too large, the airflow expands too quickly, easily generating vortices and separation; if the aspect ratio is too small, the airflow guidance is insufficient, making it difficult to form a stable pre-swirl.

[0044] The two endpoints of the airfoil section near the concave side of the guide vane 11 form a line, and this line forms an installation angle γ1 with the radial plane of the impeller 3, with γ1 being 80°-81°. This installation angle causes the air entering the impeller 3 to form a pre-swirling airflow with a certain direction, making the incident angle of the air relative to the blade 31 more reasonable, thereby reducing the impact loss at the leading edge of the blade 31. When the airflow enters the impeller 3 directly radially, it is easy to form a strong impact at the leading edge of the blade 31, generating periodic pressure fluctuations. However, after proper pre-swirling, the airflow can flow more smoothly along the surface of the blade 31. This reduces the pulsating noise at the inlet of the impeller 3, while also reducing the vibration of the blade 31 caused by airflow impact, and improving the operational stability of the fan.

[0045] Furthermore, the above designs are all based on the structure of the front guide vane 11 inside the air inlet duct 1. They work together from three aspects: the overall curvature of the front guide vane 11, the airflow expansion characteristics, and the guiding direction. This allows the front guide vane 11 to perform stable guiding, pre-swirl organization, and inlet turbulence reduction treatment on the airflow before it enters the impeller 3, thereby reducing airflow impact, pressure pulsation, and aerodynamic noise in the inlet area of ​​the impeller 3.

[0046] From the perspective of overall coordination, the radius of the arc of the guide vane 11 determines the overall guiding trajectory of the guide vane 11, the aspect ratio β1 determines the diffusion and velocity change process of the airflow on the surface of the guide vane 11, and the installation angle γ1 ultimately determines the flow direction angle of the air entering the impeller. After the three work together, the guide vane 11 can not only make the air form a stable pre-swirl, but also prevent the airflow from separating on the guide vane surface, thereby establishing a uniform, low-turbulence inlet flow field.

[0047] In some embodiments, please refer to Figure 1 and Figure 4 As shown, the rear guide vane 21 is an arc-shaped plate structure with a radius of 166°-168°. This design guides the air to gradually change its flow direction through a continuously curved guide surface, allowing the air, which originally had a large rotational kinetic energy, to gradually return to a more stable axial flow state. Especially under high-speed operation of the fan, the air velocity is high, and the airflow is prone to forming vortices at the fan tail, thus causing high-frequency broadband noise. Therefore, the arc-shaped rear guide vane 21 structure allows the air to form a continuous adhering flow along the guide vane surface, reducing the degree of turbulence in the guide vane wake.

[0048] Furthermore, the rear guide vane 21 not only serves a guiding function but also a certain degree of diffusion. The air exiting the impeller 3 typically has a high velocity and a large proportion of kinetic energy. The rear guide vane 21, through its arc-shaped expansion structure, can gradually convert some of this kinetic energy into static pressure, thereby improving the overall air pressure utilization rate of the fan. Since the fan is used for cooling the braking resistors of locomotives, it needs to provide stable airflow and air pressure over a long period. Therefore, the diffusion stability of the rear guide vane 21 directly affects the overall heat dissipation efficiency of the unit.

[0049] Because the air discharged from impeller 3 has a high velocity and strong rotational kinetic energy, the rear guide vane 21 needs to adjust the airflow direction and reduce its velocity within a short distance. If the rear guide vane 21 expands insufficiently, the rotational component in the air cannot be effectively eliminated, and a strong swirling flow will remain in the wake, resulting in unstable outlet airflow. However, if the expansion is too large, the air flowing on the guide vane surface will experience boundary layer separation due to excessively rapid pressure recovery, leading to vortices and flow separation zones at the guide vane tail.

[0050] Therefore, the two endpoints of the airfoil section near the convex side of the rear guide vane 21 form two tangents, which together form an aspect angle β2 of 38°-39°. This larger aspect angle means that the air expands significantly inside the rear guide vane 21, thereby reducing the peak outlet airflow velocity and weakening the high-speed rotating core region in the impeller 3 wake. Since high-speed swirling flow is a significant source of howling noise at the fan tail, reducing the swirling flow intensity can effectively reduce the fan's broadband noise and wake pulsation.

[0051] Meanwhile, this angle also improves the static pressure recovery capability of the airflow output from impeller 3. Impeller 3 itself mainly inputs kinetic energy into the air, while the guide vane 21 is responsible for converting some of the kinetic energy into static pressure. When the angle is controlled within a reasonable range, the air gradually decelerates along the guide vane surface, and the static pressure gradually increases, thereby improving the stability of the fan outlet pressure. For brake resistor fans, stable air pressure ensures that cooling air continuously passes through the brake resistor area, improving heat dissipation efficiency.

[0052] The two endpoints of the airfoil section near the concave side of the rear guide vane 21 form a line, and this line forms an installation angle γ2 with the radial plane of the impeller 3, with γ2 being 73°-74°. The airflow output from the impeller 3 has a significant rotational tendency, and one of the main tasks of the rear guide vane 21 is to gradually weaken this rotational component. If the installation angle of the rear guide vane 21 is too large, the air will undergo excessive turning inside the guide vane, thus forming a new flow separation; if the installation angle is too small, the guide vane cannot effectively weaken the swirling flow. Therefore, this design controls γ2 between 80°-81°, causing the air to undergo a moderate deflection inside the rear guide vane 21, thereby gradually restoring stable axial flow.

[0053] Furthermore, unlike the leading vane 11, the trailing vane 21 has a higher wind speed than the leading vane, and the trailing vane 21 no longer emphasizes establishing pre-swirl, but rather emphasizing swirl reduction. Therefore, the installation angle of the trailing vane 21 is significantly larger than that of the leading vane 11, and the large-angle guidance can make the air turn and decelerate more quickly.

[0054] The distance between the outer diameter of the blade 31 and the inner wall of the outer cylinder of the air inlet duct 1 is 2mm-5mm, and the distance between the outer diameter of the blade 31 and the inner wall of the outer cylinder of the air outlet duct 2 is 2mm-5mm.

[0055] When the impeller 3 is working, there is a significant pressure difference between the pressure surface and the suction surface of the blades 31. Therefore, the high-pressure side air tends to leak from the blade tip gap to the low-pressure side, forming a blade tip leakage flow. This leakage flow will entrain and form a strong blade tip vortex in the blade tip region. The blade tip vortex will not only reduce the actual work capacity of the impeller 3, but also generate significant high-frequency noise and periodic pulsation.

[0056] If the blade tip clearance is too large, the leakage flow will increase, the blade tip vortex intensity will significantly increase, leading to a decrease in fan efficiency, increased blade tip screeching, aggravated wake turbulence, and increased pressure pulsation. Conversely, if the clearance is too small, although leakage will be reduced, under high-speed rotation conditions, impeller thermal expansion, bearing vibration, and manufacturing errors may cause the blades 31 to rub against and collide with the fan casing, thus affecting operational safety. Therefore, this design controls the clearance between 2mm and 5mm to effectively suppress blade tip leakage while balancing manufacturing tolerances and operational reliability.

[0057] The gap distance L1 between the impeller 3 and the opposite end face of the air inlet duct 1 is 16mm-18mm, and the gap distance L2 between the impeller 3 and the opposite end face of the air outlet duct 2 is 9mm-11mm.

[0058] Although this gap area is not part of the main flow path of the fan, and the main airflow path does not directly pass through this location, the air near the impeller end face is affected by rotational shearing due to the high-speed rotation of impeller 3, thus creating secondary flow in the gap area. If the gap design is unreasonable, local backflow, rotating vortices, and pressure pulsations can easily form near the impeller end face, thereby affecting the stability of the entire fan flow field and increasing aerodynamic noise and vibration.

[0059] Specifically, when impeller 3 rotates at high speed, its front and rear end faces drive the adjacent air to rotate synchronously. Due to the velocity difference between the end face and the fixed duct end face, the air in the gap is subjected to strong shearing. When the gap is too large, the air near the end face can easily form a large swirling backflow space, causing the air to generate annular vortices in that area. Especially for high-speed fans, end face vortices can further induce low-frequency pulsating noise and casing vibration, and may couple with the mainstream.

[0060] Therefore, this design controls the gap between the front and rear ends of impeller 3, thus limiting the rotation space of the air near the end face, thereby reducing the intensity of the backflow and the scale of local vortices at the end face. Because the gap is reduced, it becomes difficult for air to form large-scale circulating flow in the end face region, thus reducing the turbulent energy in the end face region and weakening the propagation of pressure pulsations.

[0061] On the other hand, since the impeller is rotating at high speed, bearing vibration, thermal expansion, and assembly errors will occur during operation. If the end face clearance is too small, the end face of impeller 3 is prone to friction or even collision with the end face of the inlet duct 1 or outlet duct 2 during operation. Therefore, this design retains a certain safety clearance to ensure that the impeller can maintain reliable operation under high-speed conditions.

[0062] During wind turbine operation, the blades 31 of impeller 3 periodically sweep across the front guide vane 11 and the rear guide vane 21, resulting in periodic pressure fluctuations. When the number of guide vanes and blades 31 are integer multiples of each other, the frequencies of the pressure fluctuations tend to overlap, thus forming a strong sound pressure peak at a specific frequency, known as the blade 31 passing frequency noise. This noise typically manifests as a noticeable howling sound and may induce structural resonance.

[0063] Therefore, the ratio of the number of leading vane 11, blade 31, and trailing vane 21 in this design is 12:13:19. This design ensures that there is no simple integer multiple relationship between the three sets of blades, thus effectively dispersing the interference frequency of blade 31.

[0064] Meanwhile, varying the number of blade cascades can also reduce wake synchronicity. If the number of blade cascades is the same, the wake will periodically and repeatedly act on the same position, easily forming a fixed excitation source. This scheme, by designing a non-integer multiple number of blade cascades, makes the wake's position constantly change, thereby reducing local fatigue and structural vibration.

[0065] Furthermore, this ratio also considers both guiding capacity and impeller 3 load balance. The number of leading vanes 11 affects the uniformity of inlet pre-swirl, the number of blades 31 affects the work capacity, and the number of trailing vanes 21 affects swirl reduction and rectification accuracy. The ratio of 12:13:19 means that the leading vanes 11 can form a more uniform inlet flow field, the impeller 3 maintains an appropriate blade 31 load, and the trailing vanes 21 improve wake rectification accuracy through more blades 31.

[0066] In one embodiment, the impeller 3 of the present invention has an airfoil-like blade structure 31, an impeller diameter of Φ630mm, 13 evenly distributed blades, 11 evenly distributed front guide vanes 11, and 19 evenly distributed rear guide vanes 21. The fan needs to meet a flow rate ≥8.1m³ / s. 3 / s, static pressure ≥1300Pa, rated power ≤32kW.

[0067] The performance parameters of the wind turbine at different blade installation angles of 31° are shown in the table below: Table 1 shows the performance parameters for the wind turbine impeller when the installation angle α1 is 43° and α2 is 27°:

[0068] Table 2 shows the performance parameters for the wind turbine impeller installation angles α1 and α2 when they are 43.3° and 27.3° respectively.

[0069] Table 3 shows the performance parameters when the impeller installation angle α1 is 43.8° and α2 is 27.8°:

[0070] Table 4 shows the performance parameters when the impeller installation angle α1 is 44.3° and α2 is 28.3°:

[0071] Table 5 shows the performance parameters when the impeller installation angle α1 is 47° and α2 is 31°:

[0072] A comparison of performance data for different blade installation angles (31°) under varying flow conditions reveals that the 31° installation angle significantly impacts the fan's flow rate, static pressure, efficiency, and power. Essentially, it alters the blade's airflow angle of attack and work capacity, thus affecting the overall aerodynamic matching. The following analysis considers the target operating conditions (flow rate ≥ 8.1 m³ / s, static pressure ≥ 1300 Pa, power ≤ 32 kW): When the installation angle is small, the work capacity of blade 31 for airflow is relatively insufficient. For example, when α1 is 43° and α2 is 27°, although the power is low, the static pressure margin is small in the target flow range, and the system adaptability is insufficient.

[0073] When the installation angle increases to, for example, α1 is 47° and α2 is 31°, the static pressure of the fan increases significantly within the target flow range, but the power growth accelerates significantly, gradually approaching or even exceeding the rated power limit. At the same time, the increased blade load leads to an increase in the risk of flow separation and eddy current loss, and the efficiency improvement is no longer significant.

[0074] Therefore, when α1 is 43.3°-44.3° and α2 is 27.3°-28.3°, it falls within an optimal operating range of overall balance. At this angle, the blade's angle of attack (31°) is within the high-efficiency lift-to-drag ratio range of the airfoil structure, ensuring sufficient pressure lift and flow output while avoiding aerodynamic stall and a sharp increase in power caused by large angles. Simultaneously, this angle is more rationally matched with the overall flow channel system formed by inlet duct 1 and outlet duct 2, resulting in smoother airflow inlet and outlet swirl, reducing eddies and energy loss. Under the constraints of the target operating conditions, this angle range not only stably meets the performance indicators but also achieves the best balance between efficiency, power consumption, and aerodynamic stability, thus exhibiting the characteristics of optimal overall performance.

[0075] This invention selects a wind turbine design scheme and structural combination with α1 = 43.8° and α2 = 27.8°. The wind turbine simulation test results are as follows: Figures 5-7 As shown, the aerodynamic performance of the fan operates at the normal pressure-flow point. The air volume entering the air inlet duct 1 is 8.1 m3 / s, the static pressure is ≥1300 Pa, the sound power noise is <119 dB(A), and the weight is 235 kg.

[0076] With the layout and distribution of the guide vanes and blades 31 inside the wind tunnel of the present invention, the vibration of the fan is very small. When the fan is running under rated operating conditions, the vibration velocity value of the fan is ≤2.8mm / s.

[0077] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. An integrated dual-source locomotive braking resistor fan, characterized in that, include: The air inlet duct (1) has multiple guide vanes (11) arranged circumferentially inside it. The air outlet (2) has multiple rear guide vanes (21) arranged circumferentially along its inner edge. Impeller (3) is located between air inlet (1) and air outlet (2). Impeller (3) has multiple blades (31) arranged circumferentially. The airfoil section of blade (31) has two flanges on the side near the pressure surface and the two flanges have a common tangent. The common tangent and the radial plane of impeller (3) form an installation angle α. In the direction of extension of the blade (31) from the root to the tip, the installation angle of the blade (31) gradually transitions from α1 to α2, with α1 being 43.3°-44.3° and α2 being 27.3°-28.3°.

2. The integrated dual-source locomotive braking resistor fan according to claim 1, characterized in that, The leading vane (11) is an arc plate-shaped structure with an arc radius of R310-R315.

3. The integrated dual-source locomotive braking resistor fan according to claim 1, characterized in that, The two endpoints of the airfoil section of the leading blade (11) near the convex side form two tangents, which form an angle β1 with a value of 18.5°-19.5°.

4. The integrated dual-source locomotive braking resistor fan according to claim 1, characterized in that, The two endpoints of the airfoil section of the leading blade (11) near the concave side form a line, and the line forms an installation angle γ1 with the radial plane of the impeller (3), and the angle γ1 is 80°-81°.

5. The integrated dual-source locomotive braking resistor fan according to claim 1, characterized in that, The rear guide vane (21) is an arc plate structure with an arc radius of 166°-168°.

6. The integrated dual-source locomotive braking resistor fan according to claim 1, characterized in that, The two endpoints of the airfoil section of the rear guide vane (21) near the convex side form two tangents respectively, and the two tangents form an aspect angle β2, with β2 being 38°-39°.

7. The integrated dual-source locomotive braking resistor fan according to claim 1, characterized in that, The two endpoints of the airfoil section of the rear guide vane (21) near the concave side form a line, and the line forms an installation angle γ2 with the radial plane of the impeller (3), and the angle γ2 is 73°-74°.

8. The integrated dual-source locomotive braking resistor fan according to claim 1, characterized in that, The distance between the outer diameter of the blade (31) and the inner wall of the outer cylinder of the air inlet (1) is 2mm-5mm, and the distance between the outer diameter of the blade (31) and the inner wall of the outer cylinder of the air outlet (2) is 2mm-5mm.

9. The integrated dual-source locomotive braking resistor fan according to claim 1, characterized in that, There is a gap of 16mm-18mm between the impeller (3) and the air inlet (1) and a gap of 9mm-11mm between the impeller (3) and the air outlet (2).

10. An integrated dual-source locomotive braking resistor fan according to claim 1, characterized in that, The ratio of the number of leading leaf (11), leaf blade (31), and posterior leading leaf (21) is 12:13:19.

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