Mixed flow fans and duct fans

Abstract

This invention provides a mixed-flow fan and a ducted air conditioner. The mixed-flow fan includes a volute with an air outlet; an impeller disposed within the volute; and an inner shell disposed between the impeller and the air outlet, with an annular air duct formed between the outer surface of the inner shell and the inner surface of the volute. The width of the annular air duct gradually increases along the direction from the impeller to the air outlet. The mixed-flow fan and ducted air conditioner provided by this invention, by gradually increasing the width of the annular air duct, regulate the static pressure and airflow velocity of the air outlet from the impeller, thereby effectively improving the air outlet effect of the mixed-flow fan. This ensures optimal heat exchange in both waterfall cooling and rapid heating modes of the ducted air conditioner. Simultaneously, the rear guide vane structure expands with the increase in the width of the annular air duct, ensuring the adjustment effect of the rear guide vane structure on the air outlet from the impeller.

Description

Technical Field

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

[0002] Ductless air conditioners are a type of air conditioner. 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 outlet, cross-flow fans and centrifugal fans are usually used. However, due to the design of the fan blades, the airflow direction cannot be reversed after reversing. Therefore, at least two fans must be set up, one responsible for forward air outlet and one responsible for reverse air outlet. This not only makes the ductless air conditioner structure larger but also increases the cost.

[0003] To reduce costs, fans need to be miniaturized. Mixed-flow fans are a type of fan that falls between axial and centrifugal fans. The impeller of a mixed-flow fan causes the air to undergo both centrifugal and axial motion. The airflow within 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 correct airflow direction and pressure.

[0004] The airflow channel design inside the existing mixed-flow fan is unreasonable, resulting in low energy efficiency. Summary of the Invention

[0005] This invention provides a mixed-flow fan and a duct fan to solve the problem of low energy efficiency of mixed-flow fans in the prior art.

[0006] A mixed-flow fan, comprising:

[0007] A volute, on which an air outlet is provided;

[0008] An impeller, wherein the impeller is disposed within the volute;

[0009] The inner shell is disposed between the impeller and the air outlet, and an annular air duct is formed between the outer surface of the inner shell and the inner surface of the volute.

[0010] The width of the annular air duct gradually increases along the direction from the impeller to the air outlet.

[0011] The annular air duct has a first end and a second end, the second end being connected to the air outlet, and the ratio of the width a of the first end to the width b of the second end is in the range of 0.68 < a / b < 0.88.

[0012] The mixed-flow fan also includes a rear guide vane structure, which is disposed within the annular air duct.

[0013] The rear guide vane structure includes multiple guide vanes, with the first edge of the guide vane facing the outer surface of the inner shell and the second edge of the guide vane facing the inner surface of the volute.

[0014] At least one of the guide vanes is provided with a swing shaft, the axis of the swing shaft is at an angle to the axis of the impeller, and the guide vane with the swing shaft is able to swing about the axis of the swing shaft.

[0015] The included angle is 90°.

[0016] The rear guide vane structure is provided with noise-reducing teeth.

[0017] The rear guide vane structure is provided with protrusions and / or recesses; and / or the outer surface of the inner shell is provided with protrusions and / or recesses.

[0018] The outer surface of the volute is curved.

[0019] The volute is a spherical structure, and the maximum diameter of the volute is equal to the diameter of the spherical structure.

[0020] The volute is provided with the air inlet and the air outlet at the two end faces of the table structure.

[0021] A ducted air handling unit, comprising the aforementioned mixed-flow fan.

[0022] The mixed-flow fan and duct fan provided by this invention adjust the static pressure and airflow velocity of the impeller outlet by gradually increasing the width of the annular flow channel, thereby effectively improving the air outlet effect of the mixed-flow fan. When the mixed-flow fan is applied in the duct fan, it can ensure that the optimal heat exchange effect can be achieved in both the waterfall cooling and rapid heating modes of the duct fan. At the same time, the rear guide vane structure also expands with the increase of the width of the annular flow channel, ensuring the adjustment effect of the rear guide vane structure on the air outlet of the impeller. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of a mixed-flow fan according to an embodiment of the present invention;

[0024] Figure 2 This is a schematic diagram of the annular air duct and guide vanes provided in an embodiment of the present invention;

[0025] Figure 3 A perspective view of the annular air duct and guide vanes provided in an embodiment of the present invention;

[0026] In the picture:

[0027] 1. Volute; 12. Air outlet; 2. Impeller; 4. Inner casing; 13. Annular air duct; 131. First end; 132. Second end; 33. Guide vane; 34. Swing shaft. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention.

[0029] In existing mixed-flow fans, when the impeller 2 rotates at high speed, it drives airflow out of the impeller 2 with high dynamic pressure, and the air continues to flow between the outlet of the impeller 2 and the volute 1, ultimately forming the outlet air of the mixed-flow fan. A large tangential velocity exists when the gas exits the impeller 2; this tangential velocity component is detrimental to subsequent flow. Therefore, existing technologies incorporate an anti-swirl section and a rear guide vane structure between the outlet of the impeller and the volute. The anti-swirl section guides the high-speed rotating airflow from radial to horizontal direction, and the sudden pressure release converts some of the dynamic pressure of the airflow into static pressure to support subsequent flow. Although the anti-swirl section can guide the rotating airflow horizontally, it still carries a large tangential velocity, all of which are detrimental to subsequent flow. The function of the rear guide vane structure is to convert more of the tangential velocity of the airflow into horizontal velocity and again convert the large dynamic pressure into static pressure, thereby improving the fan's pressure-carrying capacity. In existing technologies, improving the energy efficiency of fans is achieved by adjusting the structure of the impeller. However, after the applicant's research on the principle of airflow and analysis of simulation experimental data, it was found that the shape of the annular air duct formed between the inner shell and the volute can effectively change the conversion efficiency between the dynamic pressure and static pressure of the gas. Therefore, the appropriate variation in the width of the annular air duct is extremely important for improving the performance of the mixed flow fan system.

[0030] Based on the above reasons, such as Figures 1 to 3 As shown, a mixed-flow fan includes: a volute 1 with an outlet 12; an impeller 2 disposed within the volute 1; and an inner shell 4 disposed between the impeller 2 and the outlet 12, with an annular duct 13 formed between the outer surface of the inner shell 4 and the inner surface of the volute 1. The width of the annular duct 13 gradually increases along the direction from the impeller 2 to the outlet 12. By utilizing the gradually increasing width of the annular duct 13, the tangential velocity component of the gas entering the annular duct 13 gradually decreases, while the static pressure gradually increases, thereby effectively improving the fan's pressurization capacity.

[0031] The annular air duct 13 has a first end 131 and a second end 132, the second end 132 is connected to the air outlet 12, and the ratio of the width a of the first end 131 to the width b of the second end 132 is in the range of 0.68 < a / b < 0.88.

[0032] A simulation experiment was conducted on the mixed-flow fan in this example, adjusting the value of a / b. The simulation results are as follows:

[0033] a / b Rotational speed (rpm) <![CDATA[Calculated air volume (m 3 / h)]]> Impeller head (Pa) Diffusion loss (Pa) 0.62 2200 478 100.1 62.3 0.68 2200 496 114.6 48.1 0.80 2200 510 126.8 36.2 0.88 2200 493 113.4 44.8 0.92 2200 472 108.3 58.6

[0034] The simulation results show that when a / b is 0.80, the airflow and impeller head reach their maximum values, and the diffusion loss is minimal. When a / b increases to 0.88, the airflow and impeller head begin to decrease, and the diffusion loss increases. When a / b continues to increase to 0.92, the airflow and impeller head further decrease, and the diffusion loss continues to increase. When a / b decreases to 0.68, the airflow and impeller head begin to decrease, and the diffusion loss increases. When a / b continues to increase to 0.62, the airflow and impeller head further decrease, and the diffusion loss continues to increase. In other words, when the value of a / b is small, it means that the value of a is small and the value of b is large. At this time, the airflow flowing through the annular duct 13 is in a state of rapid diffusion, which will cause a rapid loss of pressure and affect the pressurized performance of the fan. At the same time, a small value of a will also affect the size of impeller 2, resulting in a decrease in the work capacity of impeller 2, which is not conducive to improving the performance of the unit. When the value of a / b is too large, it means that the value of a is too large and the value of b is too small. In this case, the diffusion capacity of the flow through the annular duct 13 is insufficient, making it difficult to effectively carry pressure, thus reducing the pressure-carrying capacity. Simultaneously, because the value of b is too small, the flow resistance through the annular duct 13 increases, leading to increased diffusion losses, which is also detrimental to the improvement of unit performance. When the value of a / b is within a suitable range (0.68...), the diffusion capacity is reduced.

[0035] The mixed-flow fan also includes a rear guide vane structure, which is disposed within the annular air duct 13.

[0036] The rear guide vane structure includes multiple guide vanes 33. The first edge of each guide vane 33 faces the outer surface of the inner shell 4, and the second edge of each guide vane 33 faces the inner surface of the volute 1. That is, the shape of the guide vane 33 only needs to be less than or equal to the width of the corresponding annular duct 13. By guiding the airflow through the guide vanes 33 and adjusting the width of the annular duct 13, the static pressure of the airflow is simultaneously regulated, thereby ultimately ensuring the airflow performance of the mixed-flow fan.

[0037] ​At least one of the guide vanes 33 is provided with a swing shaft 34, the axis of which forms an angle with the axis of the impeller 2, and the guide vane 33 with the swing shaft 34 can swing about the axis of the swing shaft 34. The function of the rear guide vane structure is to further guide the airflow from the impeller 2. When the impeller 2 operates at different speeds, the angle at which the gas flows out of the impeller 2 is different, that is, the angle at which the airflow enters the rear guide vane structure is different. By swinging the guide vane 33, the flow angle of the airflow in the rear guide vane structure also changes accordingly, further increasing the degree of fit between the rear guide vane structure and the airflow direction from the impeller 2, thereby improving the exhaust uniformity of the mixed-flow fan and ensuring that the mixed-flow fan can achieve the optimal airflow value and optimal airflow drive performance at multiple operating speeds. Preferably, the higher the speed of the impeller 2, the greater the angle at which the airflow leaves the impeller 2, and therefore the larger the angle of inclination of the guide vane 33 needs to be. Conversely, the lower the speed of the impeller 2, the smaller the angle of inclination of the guide vane 33.

[0038] The swing angle of the guide vane 33 ranges from 0° to 10°, preferably from 0° to 5°.

[0039] The outer surface of the inner shell 4 is provided with protrusions and / or pits, which reduce noise in the airflow passing through the annular duct, effectively reducing the noise of the mixed flow fan.

[0040] The rear guide vane structure is provided with noise-reducing teeth. Preferably, the edge of the guide vane 33 is provided with noise-reducing teeth to reduce the noise generated when the airflow passes through the rear guide vane structure.

[0041] The rear guide vane structure is provided with protrusions and / or recesses. Preferably, one or both sides of the guide vane 33 are provided with protrusions and / or recesses, which reduces the noise generated when the airflow passes through the rear guide vane structure.

[0042] The outer surface of the volute 1 is curved. That is, the cross-section of the outer surface of the volute is a curved segment.

[0043] The volute 1 is a spherical structure, and the maximum diameter of the volute 1 is equal to the diameter of the spherical structure. That is, the volute 1 can rotate freely within a spherical space of fixed diameter centered on the center of the spherical structure. When applied to a ducted air conditioner and the ducted air conditioner requires vertical airflow, the ducted air conditioner can provide a spherical space of fixed diameter for the mixed-flow fan provided in this application, and the rotation of the mixed-flow fan can achieve the switching of the airflow direction of the ducted air conditioner.

[0044] The volute 1 is provided with an air inlet and an air outlet 12 at the two end faces of the table tennis structure.

[0045] A ducted air handling unit, comprising the aforementioned mixed-flow fan.

[0046] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A mixed-flow fan, characterized in that: include: A volute (1) is provided with an air outlet (12); Impeller (2), the impeller (2) is disposed inside the volute (1); Inner shell (4), the inner shell (4) is disposed between the impeller (2) and the air outlet (12), and an annular air duct (13) is formed between the outer surface of the inner shell (4) and the inner surface of the volute (1); Along the direction from the impeller (2) to the air outlet (12), the width of the annular air duct (13) gradually increases; The annular air duct (13) has a first end (131) and a second end (132), the second end (132) is connected to the air outlet (12), and the ratio of the width a of the first end (131) and the width b of the second end (132) is 0.68 < a / b < 0.

88.

2. The mixed-flow fan according to claim 1, characterized in that: The mixed-flow fan also includes a rear guide vane structure, which is disposed within the annular air duct.

3. The mixed-flow fan according to claim 2, characterized in that: The rear guide vane structure includes multiple guide vanes (33), at least one of the guide vanes (33) is provided with a swing shaft, the axis of the swing shaft is at an angle to the axis of the impeller (2), and the guide vane (33) with the swing shaft can swing about the axis of the swing shaft.

4. The mixed-flow fan according to claim 3, characterized in that: The included angle is 90°.

5. The mixed-flow fan according to claim 2, characterized in that: The rear guide vane structure is provided with noise-reducing teeth.

6. The mixed-flow fan according to claim 2, characterized in that: The rear guide vane structure is provided with protrusions and / or recesses; and / or the outer surface of the inner shell (4) is provided with protrusions and / or recesses.

7. The mixed-flow fan according to claim 1, characterized in that: The outer surface of the volute (1) is curved.

8. The mixed-flow fan according to claim 1, characterized in that: The volute (1) is a ball table structure, and the maximum diameter of the volute (1) is equal to the diameter of the ball table structure.

9. The mixed-flow fan according to claim 8, characterized in that: The volute (1) is provided with an air inlet and an air outlet (12) at the two end faces of the table structure.

10. A ducted air conditioner, characterized in that: Includes the mixed-flow fan as described in any one of claims 1 to 9.

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