Mixed flow fan and ducted fan

Abstract

The application discloses a mixed-flow fan and a ducted air conditioner, and relates to the technical field of air conditioners. The mixed-flow fan comprises a volute, a flow collector, an impeller, and the like. The flow collector is arranged at an air inlet position of the volute, and has a flow guide channel in communication with the interior of the volute. The inner diameter of the air inflow end of the flow guide channel is D1. The impeller is arranged in the interior of the volute, and the maximum diameter of the impeller is D2. The ratio of D1 / D2 is in the range of 0.8-0.9. The mixed-flow fan adjusts the ratio of the inner diameter of the air inflow end of the flow guide channel and the maximum outlet diameter of the impeller, so that the air flow encounters smaller resistance and generates less turbulence during the process of flowing through the flow collector and the impeller. Under the condition that the volume of the whole mixed-flow fan is limited, the air volume is increased by nearly 6%, the pressure head is increased by nearly 8%, and the calculation efficiency is increased by nearly 6%. The power of the mixed-flow fan is greatly improved, and the efficiency of the mixed-flow fan is higher.

Description

Technical Field

[0001] This invention relates to the field of air handling equipment technology, specifically to a mixed-flow fan and a duct fan. Background Technology

[0002] Ductless air conditioners are a type of air conditioning system. To improve comfort, some ductless air conditioners use a top-discharge cooling and bottom-discharge heating method, which can achieve waterfall-style cooling and carpet-style heating. To achieve this air outlet method, the air outlet of the ductless air conditioner needs to be reversible. Among the existing ductless air conditioners with reversible air outlets, cross-flow mixed-flow fans and centrifugal mixed-flow fans are usually used. However, due to the design of the fan blades of these mixed-flow fans, the airflow direction cannot be reversed after reversing. Therefore, at least two mixed-flow fans must be set up, one responsible for forward air outlet and one responsible for reverse air outlet. This not only makes the mixed-flow fan structure larger but also increases the cost.

[0003] To reduce costs, mixed-flow fans need to be miniaturized. A mixed-flow fan is a type of fan that falls between an axial mixed-flow fan and a centrifugal mixed-flow fan. The impeller of a mixed-flow fan causes the air to undergo both centrifugal and axial motions. The airflow motion inside the casing combines both axial and centrifugal motions, hence the name "mixed-flow." Moreover, mixed-flow fans can not only be made smaller in size, but also maintain the airflow direction and air pressure.

[0004] However, due to size limitations, the air delivery effect of existing mixed-flow fans is limited. How to improve air delivery efficiency under the existing size limitations is an urgent problem to be solved in this field. Summary of the Invention

[0005] This invention discloses a mixed-flow fan and duct fan, which solves the problem that the air delivery effect of existing mixed-flow fans is limited due to size constraints.

[0006] According to one aspect of the present invention, a mixed-flow fan is disclosed, comprising: a volute; a collector disposed at the air inlet of the volute, the collector having a guide channel communicating with the interior of the volute, the inner diameter of the airflow inlet end of the guide channel being D1; and an impeller disposed inside the volute, the impeller having a maximum diameter of D2, and the ratio of D1 / D2 being in the range of 0.8 to 0.9.

[0007] Furthermore, the flow guiding channel also has an airflow outlet end, and the inner diameter of the flow guiding channel at the airflow outlet end is D3, with the range of D1 / D3 being 1.2 to 1.

[0008] Furthermore, the distance from the airflow inlet to the airflow outlet is H1, and the range of H1 / D2 is 0.1 to 0.3.

[0009] Furthermore, the flow channel also has a contraction section located between the airflow inlet end and the airflow outlet end, and the flow area of ​​the contraction section gradually decreases in the direction from the airflow inlet end to the airflow outlet end.

[0010] Furthermore, in the direction from the airflow inlet to the airflow outlet, the rate of change of the flow area of ​​the contraction section gradually decreases.

[0011] Furthermore, in the direction from the airflow inlet to the airflow outlet, the rate of change of the shrinkage area of ​​the contraction section remains unchanged.

[0012] Furthermore, the flow channel also has a straight section connected to the contraction section, and the straight section is located between the contraction section and the airflow outlet end.

[0013] Furthermore, the impeller includes blades, the maximum height of which is H2 in the direction of the impeller axis, and the range of H2 / D2 is 0.38 to 0.48.

[0014] Furthermore, the impeller also includes a wheel cover, the inside of which forms an airflow channel, and the blades are located within the airflow channel; the airflow channel has an expansion section, which is located between the air inlet end and the air outlet end of the airflow channel, and the flow area of ​​the expansion section gradually increases in the direction from the air inlet end to the air outlet end of the airflow channel.

[0015] Furthermore, the volute is also provided with an air outlet; the distance between the airflow inlet end of the guide channel and the air outlet is A, and the ratio of H2 / A is in the range of 0.37 to 0.47.

[0016] Furthermore, along the radial direction of the impeller, the maximum diameter of the volute is B, and the ratio of B / D2 ranges from 1.1 to 1.25.

[0017] Furthermore, the line connecting the center of the airflow inlet end of the guide channel and the center of the air outlet is collinear with the axis of the impeller.

[0018] Furthermore, the surface of the blade has pits and / or protrusions.

[0019] According to a second aspect of the present invention, a duct fan is disclosed, comprising the aforementioned mixed-flow fan.

[0020] The mixed-flow fan of the present invention adjusts the ratio of the inner diameter of the airflow inlet end of the guide channel to the maximum outlet diameter of the impeller, so that the airflow encounters less resistance and generates less turbulence during the flow of the collector and impeller. Under the condition of limited overall mixed-flow fan volume, the air volume is increased by nearly 6%, the pressure head is increased by nearly 8%, and the calculation efficiency is increased by nearly 6%, which greatly improves the work capacity of the mixed-flow fan and makes the mixed-flow fan more efficient. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of the mixed-flow fan according to Embodiment 1 of the present invention;

[0022] Figure 2 This is a schematic diagram of the impeller structure of the mixed-flow fan according to Embodiment 1 of the present invention;

[0023] Figure 3 This is a schematic diagram of the collector of the mixed-flow fan according to Embodiment 2 of the present invention;

[0024] Legend: 10. Volute; 11. Air outlet; 20. Collector; 21. Guide channel; 30. Impeller; 31. Blade; 32. Wheel cover. Detailed Implementation

[0025] The present invention will be further described below with reference to embodiments, but is not limited to the contents of the specification.

[0026] In existing mixed-flow fans, a collector is typically installed at the air inlet. The collector smoothly and evenly guides the gas from the inlet side into the fan, reducing flow losses and improving efficiency. Therefore, the collector's structure affects the fan's performance. A well-designed collector results in minimal flow losses, while a poorly designed one deteriorates inlet conditions, leading to performance degradation.

[0027] Currently, conventional optimization methods for the collector structure mainly focus on its height, inlet size, outlet size, and guide surface shape. While these improvements can enhance the air delivery efficiency of mixed-flow fans to some extent, the applicant's research on airflow principles and analysis of simulation data revealed that these conventional improvements to the collector's structural parameters have a very limited impact on the mixed-flow fan's airflow. The reason for this is that during operation, the airflow entering and exiting the mixed-flow fan is a continuous, integrated process. Therefore, when considering improvements, one cannot simply optimize the parameters of a single component while neglecting the coordination between the collector's parameters and those of other components of the mixed-flow fan. Ironically, this neglected coordination between the collector's parameters and other components of the mixed-flow fan is precisely where improvements can effectively increase the fan's airflow.

[0028] Based on the above reasons, such as Figure 1 and Figure 2 The first embodiment of the present invention shown discloses a mixed-flow fan, including a volute 10, a collector 20, and an impeller 30. The collector 20 is connected to the volute 10 and is located at the air inlet of the volute 10. The collector 20 has a guide channel 21 communicating with the inside of the volute 10, and the inner diameter of the airflow inlet end of the guide channel 21 is D1. The impeller 30 is located inside the volute 10, and the maximum diameter of the impeller 30 is D2. The range of D1 / D2 is 0.8 to 0.9.

[0029] The mixed-flow fan of the present invention achieves superior performance data by setting the ratio of D1 / D2 to 0.8-0.9. In this embodiment, the inner diameter of the airflow inlet end of the guide channel 21 is D1, meaning D1 is the inlet diameter of the entire mixed-flow fan, and D2 is the maximum outlet diameter of the impeller 30. With a reasonable ratio between these two values, the mixed-flow fan can obtain relatively excellent performance data. Simulation data are as follows:

[0030] D1 / D2 Rotational speed (rpm) <![CDATA[Calculated air volume (m 3 / h)]]> Calculate the pressure head (Pa). Computational efficiency (%) 0.78 2200 482 84.9 64.7 0.80 2200 501 86.3 67.2 0.84 2200 510 90.4 69.1 0.90 2200 498 87.9 66.3 0.93 2200 485 83.5 64.3

[0031] Simulation data shows that when the D1 / D2 value is between 0.8 and 0.9, while ensuring the intake volume, the airflow can enter the impeller 30 smoothly and evenly. This results in less resistance and less turbulence encountered by the airflow as it flows through the collector 20 and impeller 30, reducing the intake resistance of the impeller 30. Consequently, the working capacity of the impeller 30 increases, leading to improvements in the airflow and head of the mixed-flow fan, as well as increased computational efficiency. Specifically, when the D1 / D2 value is 0.84, the intake volume is larger, but the turbulence is minimized, and the intake resistance of the impeller 30 is lowest. Therefore, the airflow, head, and computational efficiency are significantly improved, with the airflow increasing by nearly 6%. The pressure head increases by nearly 8%, and the computational efficiency increases by nearly 6%. When D1 / D2 decreases to 0.78, the flow surface at the air inlet is reduced too much, affecting the air intake. Therefore, the air volume and pressure head of the mixed-flow fan are severely reduced, and the efficiency of the mixed-flow fan is also significantly reduced, reaching a state where it cannot be used. When D1 / D2 increases to 0.93, although the air intake is guaranteed, the impeller 30 is too large, which means that the uniform airflow field cannot completely cover the impeller 30, resulting in more turbulence and increased resistance. This reduces the performance of the impeller 30, severely reducing the air volume and pressure head of the mixed-flow fan, and the efficiency of the mixed-flow fan is also significantly reduced.

[0032] The mixed-flow fan of the present invention increases the airflow rate, reduces resistance, and generates less turbulence during the airflow process as it passes through the collector 20 and impeller 30 by adjusting the ratio of the inner diameter of the airflow inlet end of the guide channel 21 to the maximum outlet diameter of the impeller 30. Under the condition of limited overall mixed-flow fan volume, this increases the airflow by nearly 6%, the pressure head by nearly 8%, and the calculation efficiency by nearly 6%, greatly improving the work capacity of the mixed-flow fan and making it more efficient.

[0033] Furthermore, the guide channel 21 also has an airflow outlet end, and the inner diameter of the guide channel 21 at the airflow outlet end is D3, with the D1 / D3 ratio ranging from 1.2 to 1. In this invention, the mixed-flow fan uses a D1 / D3 ratio ranging from 1.2 to 1. For the collector 20, the size of D1 is generally larger than the size of D3. However, to ensure the rotatable function of the mixed-flow fan, a larger D1 / D3 value will increase the external dimensions of the mixed-flow fan, affecting the overall layout. Conversely, a smaller D1 / D3 value will not achieve the function of collecting airflow, and the performance of the mixed-flow fan will decrease. Simulation experiments were conducted on the mixed-flow fan of this embodiment, changing the D1 / D3 values. The simulation results are as follows:

[0034] D1 / D3 Rotational speed (rpm) <![CDATA[Calculated air volume (m 3 / h)]]> Calculate the pressure head (Pa). Computational efficiency (%) 1.15 2200 510 90.4 69.1 1.00 2200 476 83.6 65.2 0.99 2200 460 82.1 64.3

[0035] Simulation data shows that a D1 / D3 value greater than 1.2 affects the overall layout of the mixed-flow fan and is therefore not considered. When the D1 / D3 value is 1.15, while ensuring the intake volume, the airflow enters the impeller 30 smoothly and evenly. This minimizes the resistance encountered by the airflow as it flows through the collector 20 and impeller 30, resulting in minimal turbulence and significantly reducing the intake resistance of the impeller 30. Therefore, the impeller 30 performs optimally, and the mixed-flow fan achieves the highest airflow and head. The mixed-flow fan has the highest efficiency. When D1 / D3 decreases to 1.00, the size of the inlet end decreases, the air intake is affected, and the air intake resistance increases significantly. Therefore, the air volume and pressure head of the mixed-flow fan decrease significantly, and the efficiency of the mixed-flow fan also decreases significantly. When the value of D1 / D3 decreases to 0.99, since the collector 20 cannot perform the function of collecting air, it can be seen from the table above that the air volume of the mixed-flow fan is severely reduced, and the pressure head and efficiency of the mixed-flow fan are much lower than the data with a ratio of 1.15.

[0036] It should be noted that when the values ​​of D1 / D2 are between 0.8 and 0.9 and the values ​​of D1 / D3 are between 1.2 and 1, the uniform velocity field generated by the collector 20 can completely cover the rotation range of the impeller 30. This makes the airflow resistance at each position of the impeller 30 more even when it rotates, avoiding excessive local resistance when the impeller 30 rotates. As a result, the air volume and pressure head of the mixed flow fan are significantly increased, and the efficiency of the mixed flow fan is significantly improved.

[0037] The mixed-flow fan of this invention optimizes the relationship between the inner diameter of the airflow inlet and outlet of the guide channel, resulting in less resistance and less turbulence encountered by the airflow as it flows through the collector guide channel 10. Under the condition of limited overall mixed-flow fan volume, this increases the airflow by nearly 11%, the pressure head by 10%, and the computational efficiency by nearly 5%, significantly improving the working capacity and efficiency of the mixed-flow fan. Furthermore, since the airflow is increased at the same rotational speed, the rotational speed can be reduced accordingly, thereby reducing noise during operation.

[0038] Furthermore, the distance from the airflow inlet to the airflow outlet is H1, and the ratio of H1 / D2 ranges from 0.1 to 0.3. In this invention, the mixed-flow fan sets the range of H1 / D2 to 0.1 to 0.3. If the height H1 of the collector 20 is too high relative to the maximum diameter D2 of the impeller 30, it will affect the layout and distribution of the mixed-flow fan; if H1 is too small, it will increase the intake loss of the mixed-flow fan and affect its performance. A simulation experiment was conducted on the mixed-flow fan in this example, changing the value of H1 / D2. The simulation results are as follows:

[0039] H1 / D2 Rotational speed (rpm) <![CDATA[Calculated air volume (m 3 / h)]]> Calculate the pressure head (Pa). Computational efficiency (%) 0.35 2200 495 86.1 62.9 0.30 2200 498 87.6 64.7 0.20 2200 504 88.2 67.5 0.12 2200 510 90.4 69.1 0.09 2200 496 85.5 61.4

[0040] Simulation data shows that when H1 / D2 is in the range of 0.1 to 0.3, the airflow can enter the impeller 30 smoothly and uniformly. This results in less resistance and less turbulence encountered by the airflow as it flows through the collector 20 and impeller 30, reducing the inlet resistance of the impeller 30. Consequently, the working capacity of the impeller 30 increases, thereby improving the airflow and head of the mixed-flow fan, and also increasing the computational efficiency. Specifically, when H1 / D2 is 0.12, the airflow field is the most stable and uniform, with the least turbulence, and the inlet resistance of the impeller 30 is reduced. When the air resistance is minimized, the air volume, pressure head, and computational efficiency are significantly improved. When H1 / D2 decreases to 0.09, the collector 20 becomes ineffective in collecting air, affecting the intake volume, which decreases by about 3%. As a result, the air volume and pressure head of the mixed-flow fan are severely reduced, and the efficiency of the mixed-flow fan is also significantly reduced. When H1 / D2 increases to 0.35, the collector 20 compresses the space of the impeller 30, reducing the performance of the impeller blades, which in turn severely reduces the air volume and pressure head of the mixed-flow fan, and the efficiency of the mixed-flow fan is also significantly reduced.

[0041] like Figure 1As shown, the guide channel 21 also has a contraction section, which is located between the airflow inlet and the airflow outlet. The flow area of ​​the contraction section gradually decreases in the direction from the airflow inlet to the airflow outlet. As the flow area of ​​the contraction section of the guide channel 21 gradually decreases, a gradually narrowing flow channel is formed, which accelerates the airflow and forms a uniform velocity and pressure field, thereby reducing flow losses and improving the efficiency of the mixed-flow fan.

[0042] Along the direction from the airflow inlet to the airflow outlet, the rate of decrease in the flow area of ​​the contraction section gradually decreases. In other words, the inner wall of the guide channel 21 in the contraction section is an arc-shaped inner wall, and the curvature of the inner wall gradually decreases along the direction from the airflow inlet to the airflow outlet. Under the influence of the arc of the inner wall of the collector 20, the airflow converges from the inlet of the collector 20 to the outlet of the collector 20. This arc not only guides the airflow but also reduces the flow resistance of this section to a certain extent, thereby increasing the airflow volume.

[0043] exist Figure 3 In the second embodiment shown, the rate of change of the flow area reduction in the contraction section remains constant in the direction from the airflow inlet to the airflow outlet. That is to say, the inner wall of the guide channel 21 in the contraction section is planar, and in the direction from the airflow inlet to the airflow outlet, this straight segment can also play the role of airflow guidance and concentration like an arc, and it is simple to process and has low cost.

[0044] exist Figure 1 In the illustrated embodiment 1, the flow guide channel 21 also has a straight section connected to the contraction section, located between the contraction section and the airflow outlet. This straight section is located at the tail of the collector, where the flow of the aggregated gas is relatively chaotic. This straight section can suppress the mixed airflow, thereby improving the intake conditions of the mixed-flow fan to a certain extent.

[0045] like Figure 1 and Figure 3 As shown, the impeller 30 includes blades 31. The maximum height of blades 31 along the axis of the impeller 30 is H2, and the H2 / D2 ratio ranges from 0.38 to 0.48. The value of H2 / D2 also affects the basic layout of the entire mixed-flow fan. When the value of H2 / D2 is too small, due to the insufficient H2 height of the impeller 30, an effective pressurization channel cannot be formed, and the impeller 30 cannot sufficiently diffuse the gas, resulting in insufficient pressurization capacity of the mixed-flow fan, and the blade profile of blades 31 will be more axial. When the value of H2 / D2 is too large, a large amount of radial space will be wasted to meet the rotation requirements, affecting the basic dimensions of the gas section of the mixed-flow fan. A simulation experiment was conducted on the mixed-flow fan of this embodiment, changing the value of H2 / D2. The simulation results are as follows:

[0046] H2 / D2 Rotational speed (rpm) <![CDATA[Calculated air volume (m 3 / h)]]> Impeller head (Pa) Impeller efficiency (%) 0.38 2200 501 114.3 78.3 0.40 2200 510 126.8 87.1 0.48 2200 503 115.4 79.2 0.50 2200 497 111.9 74.6

[0047] Simulation data shows that when H2 / D2 is between 0.38 and 0.48, impeller 30 can form an effective pressurization channel, sufficiently diffuse the gas, and improve the pressurization capacity of the mixed-flow fan. This results in increased airflow, pressure head, and computational efficiency. Specifically, when H2 / D2 is 0.12, impeller 30 exhibits the best gas diffusion effect, leading to the highest pressurization capacity of the mixed-flow fan and a significant improvement in airflow, pressure head, and computational efficiency. When H2 / D2 is less than 0.38, impeller 30... If the height of H2 is insufficient (0), an effective pressurization channel cannot be formed, and the impeller 30 cannot sufficiently diffuse the gas, resulting in insufficient pressurization capacity of the mixed-flow fan. Consequently, the air volume and pressure head of the mixed-flow fan are significantly reduced, and the efficiency of the mixed-flow fan is also significantly reduced. When H2 / D2 increases to 0.50, the performance of the impeller 30 actually decreases, causing the air volume and pressure head of the mixed-flow fan to decrease significantly, and the efficiency of the mixed-flow fan is also significantly reduced. In addition, increasing the size will waste a lot of radial space to meet the rotation requirements, affecting the basic dimensions of the gas section of the mixed-flow fan.

[0048] The impeller 30 also includes a cover 32, inside which an airflow channel is formed, and the blades 31 are located within the airflow channel. The airflow channel has an expansion section located between the inlet and outlet ends of the airflow channel. The flow area of ​​the expansion section gradually increases from the inlet to the outlet end of the airflow channel. By incorporating the expansion section, the static pressure of the airflow can be increased, thereby improving the efficiency of the mixed-flow fan.

[0049] The volute 10 is also equipped with an air outlet 11; the distance between the airflow inlet end of the guide channel 21 and the air outlet 11 is A, and the ratio of H2 / A ranges from 0.37 to 0.47. Here, distance A can also be understood as the length of the volute 10. Figure 1 In the vertical direction shown, the length of the volute 10 is A. A simulation experiment was conducted on the mixed-flow fan in this example, changing the value of H2 / A. The simulation results are as follows.

[0050] H2 / A Rotational speed (rpm) <![CDATA[Calculated air volume (m 3 / h)]]> Impeller head (Pa) Diffusion loss (Pa) 0.30 2200 468 91.4 49.6 0.35 2200 482 104.3 41.3 0.41 2200 510 126.8 36.2 0.48 2200 493 121.9 62.1 0.52 2200 485 116.7 73.3

[0051] Simulation data shows that when H2 / A ranges from 0.35 to 0.48, the impeller 30 has a large working surface for the airflow, ensuring the pressure-carrying capacity of the mixed-flow fan. Therefore, the airflow and pressure head of the mixed-flow fan are increased, while diffusion losses are reduced. Specifically, when H2 / A is 0.41, the mixed-flow fan has the strongest pressure-carrying capacity, resulting in a significant increase in airflow and pressure head, and a significant decrease in diffusion losses. When H2 / A decreases to 0.30, the working area of ​​the impeller 30 is insufficient, leading to insufficient pressure-carrying capacity of the mixed-flow fan. Therefore, the airflow and pressure head of the mixed-flow fan are severely reduced, and diffusion losses increase significantly. Conversely, when H2 / A increases to 0.52, the mixed-flow fan struggles to effectively convert the high dynamic pressure generated by the impeller 30 into static pressure, resulting in a deficiency in the pressure-carrying capacity of the mixed-flow fan. This leads to a severe reduction in airflow and pressure head, and conversely, a significant increase in diffusion losses.

[0052] Since the mixed-flow fan in this embodiment is installed inside the ducted air conditioner, there are process requirements and structural fit requirements for the size and shape of the volute 10 of the mixed-flow fan. Therefore, the volute 10 of the mixed-flow fan is further improved to maximize the air volume of the mixed-flow fan while meeting the above requirements of the ducted air conditioner. In this embodiment, the maximum diameter of the volute 10 along the radial direction of the impeller 30 is B, and the ratio of B / D2 ranges from 1.1 to 1.25. See also... Figure 1 As shown, the maximum diameter B of the volute 10 directly determines the shape of the volute of the mixed-flow fan, and the value of the maximum diameter B also has a corresponding relationship with the impeller 30. That is, controlling the gap between the impeller 30 and the volute in the radial direction within a certain range can increase the airflow of the mixed-flow fan. A simulation experiment was conducted on the mixed-flow fan of this embodiment, changing the value of B / D2. The simulation results are as follows.

[0053] B / D2 Rotational speed (rpm) <![CDATA[Calculated air volume (m 3 / h)]]> Impeller head (Pa) Diffusion loss (Pa) 1.04 2200 496 123.4 58.4 1.10 2200 502 124.6 50.3 1.19 2200 510 126.8 36.2 1.25 2200 504 123.7 47.6 1.30 2200 498 120.3 53.1

[0054] The airflow undergoes work through impeller 30, initially carrying high dynamic pressure. This dynamic pressure requires sufficient space to release, and a portion of it is converted into static pressure to continue flowing. Simulation data shows that when B / D2 ranges from 1.1 to 1.25, the pressure release space is ample, and the proportion of dynamic pressure converted to static pressure is relatively large, resulting in larger airflow and head, and smaller diffusion losses for the mixed-flow fan. Specifically, when B / D2 is 1.19, the proportion of dynamic pressure converted to static pressure is the highest, thus significantly increasing the airflow and head of the mixed-flow fan. The performance of the mixed-flow fan is significantly improved, and the diffusion loss is significantly reduced. When B / D2 decreases to 1.04, the pressure relief space is insufficient, which leads to a smaller ratio of dynamic pressure to static pressure. Therefore, the air volume and pressure head of the mixed-flow fan are significantly reduced, and the diffusion loss is also significantly increased. When B / D2 increases to 1.30, the fan blade performance is reduced, which leads to a significant reduction in the air volume and pressure head of the mixed-flow fan, and a significant increase in diffusion loss. Moreover, it will further increase the overall size of the mixed-flow fan and compress the basic size of other components, which is not conducive to improving the performance of the mixed-flow fan.

[0055] Preferably, in this embodiment, the volute 10 of the mixed-flow fan is a frustum structure, and the maximum diameter of the volute 10 is equal to the diameter of the frustum structure. The two bottom surfaces of the volute 10 are the airflow inlet end and the air outlet 11 of the guide channel 21, respectively. By adopting the frustum structure of the volute 10, the size of the mixed-flow fan can be minimized, thereby ensuring the air delivery effect of the mixed-flow fan.

[0056] The line connecting the center of the airflow inlet of the guide channel 21 and the center of the outlet 11 is collinear with the axis of the impeller 30.

[0057] The surface of blade 31 has pits and / or protrusions. The pits and protrusions can improve airflow, reduce noise, and increase air volume.

[0058] According to Embodiment 3 of the present invention, a duct air conditioner is disclosed, including the aforementioned mixed-flow fan. The mixed-flow fan is a type of fan intermediate between axial mixed-flow fans and centrifugal mixed-flow fans. The impeller of the mixed-flow fan causes the air to undergo both centrifugal and axial motion, and the airflow within the volute combines both axial and centrifugal motions, hence the name "mixed-flow." Because mixed-flow fans can not only be made smaller in size but also maintain the airflow direction and pressure, they can be installed within a duct air conditioner to achieve reversible airflow and change the outlet direction.

[0059] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is impossible to exhaustively list all embodiments here. All obvious variations or modifications derived from the technical solutions of the present invention are still within the protection scope of the present invention.

Claims

1. A mixed-flow fan, characterized in that, include: volute (10); A collector (20) is provided at the air inlet of the volute (10). The collector (20) has a guide channel (21) communicating with the interior of the volute (10). The inner diameter of the airflow inlet end of the guide channel (21) is D1. Impeller (30), the impeller (30) is disposed inside the volute (10), the maximum diameter of the impeller (30) is D2, and the range of D1 / D2 is 0.8 to 0.

9.

2. The mixed-flow fan according to claim 1, characterized in that, The flow channel (21) also has an airflow outlet end, and the inner diameter of the flow channel (21) at the airflow outlet end is D3, and the range of D1 / D3 is 1.2 to 1.

3. The mixed-flow fan according to claim 2, characterized in that, The distance from the airflow inlet to the airflow outlet is H1, and the range of H1 / D2 is 0.1 to 0.

3.

4. The mixed-flow fan according to claim 2, characterized in that, The flow channel (21) also has a contraction section located between the airflow inlet end and the airflow outlet end, and the flow area of ​​the contraction section gradually decreases in the direction from the airflow inlet end to the airflow outlet end.

5. The mixed-flow fan according to claim 4, characterized in that, In the direction from the airflow inlet to the airflow outlet, the rate of change of the flow area of ​​the contraction section gradually decreases.

6. The mixed-flow fan according to claim 4, characterized in that, In the direction from the airflow inlet to the airflow outlet, the rate of change of the shrinkage area of ​​the contraction section remains constant.

7. The mixed-flow fan according to claim 4, characterized in that, The flow channel (21) also has a straight section connected to the contraction section, and the straight section is located between the contraction section and the airflow outlet end.

8. The mixed-flow fan according to claim 1, characterized in that, The impeller (30) includes blades (31), the maximum height of the blades (31) in the axial direction of the impeller (30) is H2, and the range of H2 / D2 is 0.38 to 0.

48.

9. The mixed-flow fan according to claim 8, characterized in that, The impeller (30) also includes a cover (32), the inside of which forms an airflow channel, and the blades (31) are located inside the airflow channel; The airflow channel has an expansion section located between the air inlet end and the air outlet end of the airflow channel. The flow area of ​​the expansion section gradually increases in the direction from the air inlet end to the air outlet end of the airflow channel.

10. The mixed-flow fan according to claim 9, characterized in that, The volute (10) is also provided with an air outlet (11); The distance between the airflow inlet of the guide channel (21) and the air outlet (11) is A, and the ratio of H2 / A is in the range of 0.37 to 0.

47.

11. The mixed-flow fan according to claim 10, characterized in that, Along the radial direction of the impeller (30), the maximum diameter of the volute (10) is B, and the ratio of B / D2 ranges from 1.1 to 1.

25.

12. The mixed-flow fan according to claim 10, characterized in that, The line connecting the center of the airflow inlet of the guide channel (21) and the center of the air outlet (11) is collinear with the axis of the impeller (30).

13. The mixed-flow fan according to claim 8, characterized in that, The surface of the blade (31) has pits and / or protrusions.

14. A ducted air conditioner, characterized in that, The mixed-flow fan includes any one of claims 1 to 13.

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