Indoor unit of a wall-mounted air conditioner

Abstract

The utility model provides a kind of indoor unit of wall-mounted air conditioner, it is related to air conditioning technical field.The indoor unit of wall-mounted air conditioner includes: cabinet, the cabinet includes air outlet and the volute tongue and volute shell that limit to form cross-flow air duct;Cross-flow fan wheel, is located in cross-flow air duct;Wind deflector, rotatably is located at air outlet;Volute tongue is equipped with flow guide surface, on the axial direction perpendicular to cross-flow fan wheel section, flow guide surface includes sequentially connected windward section, volute tongue section and diffuser section, windward section is close to cross-flow fan wheel relative to diffuser section;Avoiding part, by part diffuser section recessed to form in the direction away from volute shell;Definition diffuser section is located between avoiding part and volute tongue section part as transition section, the size of transition section L1, avoiding part in the extension line direction of transition section size L2 satisfy: L2 / (L1+L2)≤0.75, L2 / (L1+L2)≥0.5;The arch height h of avoiding part satisfies: h≥0.08(L1+L2), h≤0.12(L1+L2).The setting effectively balances avoiding space and air duct performance, avoids the modification of volute tongue to cause negative influence to air duct performance.

Description

Technical Field

[0001] This utility model belongs to the field of air conditioning technology, and in particular relates to a wall-mounted air conditioner indoor unit. Background Technology

[0002] A typical wall-mounted air conditioner indoor unit includes a casing, an indoor heat exchanger, and a cross-flow fan. The cross-flow fan is located on the leeward side of the indoor heat exchanger and is housed within a defined cross-flow duct inside the casing. Indoor air from outside the casing enters the casing through the air inlet and exchanges heat with the indoor heat exchanger. The airflow after heat exchange is pressurized by the rotation of the cross-flow fan and then exits through the cross-flow duct. At the air outlet, it is guided by an air deflector to meet the required airflow angle.

[0003] As users' demands for comfort, energy efficiency, and quiet operation continue to rise, the market is placing higher demands on air delivery capabilities that are "wide-range, dead-zone-free, and adaptable to multiple scenarios": when cooling, "sky curtain wind" is needed—cool air diffuses along the ceiling and does not blow directly on people; when heating, "carpet wind" is needed—hot air sinks quickly and spreads along the floor. The key to achieving these functions lies in the ability of the air guide plate to rotate at a large angle and in both directions within the air outlet.

[0004] To allow the air guide plate to flip upwards and partially conceal itself within the cross-flow duct, a solution has emerged in recent years involving the fabrication of a recess at the end of the diffuser section of the volute forming the cross-flow duct. This recess provides rotational space when the air guide plate rotates, preventing interference with the wall surface and theoretically enabling the ultra-large downward tilt angle required for "carpet-like" airflow. However, current technology only addresses the "make way" aspect of the recess, lacking consideration of its coupling with the aerodynamic parameters of the cross-flow duct. This leads to significant performance degradation of the duct, excessive airflow reduction, and increased noise, becoming a bottleneck restricting the improvement of comfort in wall-mounted air conditioners. Utility Model Content

[0005] This utility model aims to at least partially solve one of the technical problems in related technologies. Therefore, This utility model provides a wall-mounted air conditioner indoor unit, which includes: The housing includes a volute tongue and a volute shell, a cross-flow air duct is formed between the volute tongue and the volute shell, and the housing includes an air outlet connected to the cross-flow air duct, the air outlet being located at the bottom front side of the housing. An indoor heat exchanger is located in the casing and exchanges heat with the air inside the casing. A cross-flow fan is installed in the cross-flow duct. As the cross-flow fan rotates, the cross-flow duct guides the heat-exchanged airflow to the air outlet. An air guide plate is rotatably disposed at the air outlet to open or close the air outlet; A drive device is mounted on the housing and connected to the air guide plate to drive the air guide plate to rotate in two directions; The volute tongue is provided with a guide surface. On a cross section perpendicular to the axial direction of the cross-flow impeller, the guide surface includes a windward section, a volute tongue section, and a diffuser section connected in sequence. The windward section is closer to the cross-flow impeller than the diffuser section. The clearance section is formed by a portion of the diffuser section that is recessed away from the volute, and is used to clear the air guide plate that rotates into the cross-flow duct. The portion of the diffuser section located between the clearance section and the volute tongue section is defined as the transition section. The size of the transition section is L1. The size L2 of the clearance section in the extension direction of the transition section satisfies: L2 / (L1+L2)≤0.75, L2 / (L1+L2)≥0.5; the arch height h of the clearance section satisfies: h≥0.08(L1+L2), h≤0.12(L1+L2).

[0006] The above technical solution has the following advantages or beneficial effects: by setting a recessed clearance part, the air guide plate can be flipped upward and embedded into the cross-flow duct, realizing a bidirectional flipping function, improving the air supply range, achieving effects such as skylight wind and carpet wind, and avoiding dead zones in air supply. The size ratio of the clearance part needs to be strictly controlled. If the ratio of L2 to (L1+L2) is too large, it means that the clearance part occupies too high a proportion in the upper profile of the volute tongue, that is, the clearance part is too close to the volute tongue section, which will cause the airflow to separate too early when passing through this point, and it will not be able to adhere to the wall surface, thus generating strong vortices, resulting in significant loss of air volume and increased noise; conversely, if the ratio is too small, the space provided by the clearance part is insufficient, which will not meet the movement stroke required for the effective upward flipping of the air guide plate, thus limiting its flipping function. Similarly, an excessively large arch height (h) means that the protrusion of the avoidance section is too high, severely disrupting the originally stable airflow. This causes the airflow to separate violently at the apex of the avoidance section, generating large-scale vortices, significantly increasing flow resistance and pressure loss, and consequently resulting in a severe reduction in airflow and a significant increase in noise. Conversely, if the arch height is too small, the protrusion of the avoidance section is insufficient, failing to provide the necessary depth for the guide plate to flip up. This causes interference between the guide plate and the upper wall of the cross-flow duct, preventing it from reaching the preset flip angle and ultimately causing the upward airflow function to fail. By setting L2 / (L1+L2) within the range of 0.5 to 0.75 and the arch height (h) within the range of 0.08 to 0.12 times (L1+L2), the upward flip function of the guide plate is achieved while minimizing the negative impact of modifications to the volute structure on the original performance of the cross-flow duct, ensuring almost no loss in airflow and noise levels.

[0007] According to an embodiment of this disclosure, the volute tongue segment is arc-shaped, and the radius of the volute tongue segment is R1, where L1 satisfies: L1 > 1.5R1.

[0008] The above technical solution has the following advantages or beneficial effects: If L1≤1.5R1, the transition section is too short, which will affect the airflow guiding effect at the volute tongue section, leading to increased noise, reduced airflow, or even unstable airflow. By setting the size L1 of the transition section to be greater than 1.5R1, the transition length between the volute tongue section and the avoidance part is ensured to be long enough, avoiding the generation of vortices in the airflow near the avoidance part, ensuring airflow stability, and reducing noise.

[0009] According to an embodiment of this disclosure, the avoidance portion is arranged in an arc shape.

[0010] The above technical solution has the following advantages or beneficial effects: the arc-shaped avoidance part can match the arc-shaped movement trajectory of the air guide plate, reducing the risk of mechanical interference when the air guide plate flips, while reducing airflow disturbance and resistance, reducing airflow impact noise, and avoiding the degradation of air duct performance.

[0011] According to an embodiment of this disclosure, the radius of the avoidance part is R2, and the outer diameter of the cross-flow fan is D2, wherein R2 satisfies: R2≤0.55D2, R2≥0.45D2.

[0012] The above technical solution has the following advantages or beneficial effects: Under the same chord length L2, the larger the radius R2, the smaller the recess depth of the avoidance part. When R2 > 0.55D2, the recess of the avoidance part is relatively gentle, and the air guide plate cannot be completely flipped up into the cross-flow duct, limiting the flipping angle. When R2 < 0.45D2, the recess of the avoidance part is too steep, the local diffusion angle increases sharply, and the airflow easily forms vortices in the avoidance part, resulting in obvious cavity noise and increased overall noise. By linking the radius R2 of the avoidance part with the outer diameter of the cross-flow impeller and setting the radius R2 within the range of 0.45D2 to 0.55D2, repeated calculations are unnecessary, significantly shortening the development cycle. At the same time, the numerical range of the above radius ensures that the shape of the avoidance part is always kept in the optimal range of "lowest vortex shedding, no airflow attenuation, and large flipping angle," maximizing the preservation of the duct performance advantages.

[0013] According to an embodiment of this disclosure, the central angle α corresponding to the avoidance portion satisfies: α ≥ 55°, α ≤ 65°.

[0014] The above technical solution has the following advantages or beneficial effects: If α > 65°, the opening of the clearance section is too large, excessively encroaching on the length of the diffuser section, causing sudden diffusion of the outlet airflow of the volute section, resulting in reduced airflow and increased noise. If α < 55°, the opening of the clearance section is too small, limiting the space for the air guide plate to rotate, causing most of the air guide plate to be exposed outside the cross-flow duct, reducing the maximum upward rotation angle, and resulting in insufficient downward pressure angle of the "carpet wind" during heating, affecting the air delivery effect. By setting the central angle α within the range of 55°~65°, the opening angle of the clearance section is matched with the rotation trajectory of the air guide plate, ensuring that the air guide plate rotates into the cross-flow duct to obtain a large upward rotation angle, while also ensuring a smooth transition of the airflow boundary layer. Airflow, noise, and structural strength are all within the optimal range, thus achieving better duct performance.

[0015] According to an embodiment of this disclosure, the air guide plate has a closed position where the air outlet is closed, and an upper limit position where it is flipped upwards to its limit. The angle β through which the air guide plate rotates from the closed position to the upper limit position satisfies: β≥65°, β≤115°.

[0016] The above technical solution has the following advantages or beneficial effects: If β < 65°, the upward tilt angle of the air guide plate is relatively small, affecting the air delivery range and effect during heating. If β > 115°, the upward tilt angle of the air guide plate is relatively large; the larger the tilt angle, the greater the airflow loss, affecting the duct performance. By setting the included angle β between 65° and 115°, a very wide stepless adjustment range can be provided, achieving multi-angle heating carpet airflow, making the air delivery more precise and user-friendly while avoiding airflow loss.

[0017] According to an embodiment of this disclosure, the air guide plate is an arc-shaped plate.

[0018] The above technical solution has the following advantages or beneficial effects: the air guide plate is arc-shaped, and the air guide plate cooperates with the arc-shaped avoidance part to improve the guiding effect of airflow.

[0019] According to an embodiment of this disclosure, the straight-line distance K between the front edge and the rear edge of the air guide plate satisfies: K≤1.5L2, K≥L2; wherein, the rotation center of the air guide plate is located on the perpendicular bisector of the line connecting the front edge and the rear edge.

[0020] The above technical solution has the following advantages or beneficial effects: If K < L2, it cannot be guaranteed that the air guide plate has sufficient length to utilize the clearance space and achieve the air guiding function; if K > 1.5L2, it means that the air guide plate is too long, which may lead to motion interference or sluggish response. By limiting the ratio of the chord length K of the air guide plate to the chord length L2 of the clearance part, the optimal geometric fit between the air guide plate and the clearance part is achieved, ensuring that the air guide plate can be smoothly embedded in the clearance part, while ensuring that the size of the air guide plate is large enough to effectively guide the airflow.

[0021] According to an embodiment of this disclosure, L1 satisfies: L1≤0.5K.

[0022] The above technical solution has the following advantages or beneficial effects: Under the constraint of a relatively fixed upper profile of the entire cross-flow duct, if L1 > 0.5K, it directly leads to the corresponding compression of L2 of the avoidance section, resulting in insufficient avoidance space for the guide plate to flip up. This restricts the movement trajectory of the guide plate, preventing it from rotating to the preset limit position, thereby reducing the upper limit angle of the guide plate and ultimately weakening the function of achieving large-angle "carpet wind" air delivery. By setting L1 ≤ 0.5K, it indirectly ensures that the airflow path from the volute section to the outlet will not cause unnecessary diffusion or energy loss due to an excessively long transition section, which helps maintain the adhesion and directionality of the airflow. At the same time, it provides reliable and sufficient avoidance space for the avoidance section, ensuring the functionality of core air delivery modes such as "carpet wind".

[0023] According to embodiments of this disclosure, a wall-mounted air conditioner indoor unit is also provided, comprising: The housing includes a volute tongue and a volute shell, a cross-flow air duct is formed between the volute tongue and the volute shell, and the housing includes an air outlet connected to the cross-flow air duct, the air outlet being located at the bottom front side of the housing. An indoor heat exchanger is located in the casing and exchanges heat with the air inside the casing. A cross-flow fan is installed in the cross-flow duct. As the cross-flow fan rotates, the cross-flow duct guides the heat-exchanged airflow to the air outlet. An air guide plate is rotatably disposed at the air outlet to open or close the air outlet; A drive device is mounted on the housing and connected to the air guide plate to drive the air guide plate to rotate in two directions; The volute tongue includes a windward section, a volute tongue portion, and a diffuser portion connected in sequence. The windward section is disposed near the cross-flow impeller relative to the diffuser portion. The volute tongue portion further includes: A clearance portion is connected to the end of the diffuser that is away from the cross-flow impeller. The clearance portion is recessed relative to the diffuser and is formed in a direction away from the volute. It is used to clear the air guide plate that rotates into the cross-flow duct. In a cross section perpendicular to the axial direction of the cross-flow impeller, the dimension of the diffuser in its own extension direction is L1, and the dimension L2 of the clearance part in the extension direction of the diffuser satisfies: L2 / (L1+L2)≤0.75, L2 / (L1+L2)≥0.5; the arch height h of the clearance part satisfies: h≥0.08(L1+L2), h≤0.12(L1+L2).

[0024] The above technical solution has the following advantages or beneficial effects: By setting a recessed clearance section, the air guide plate can be flipped upwards and embedded into the cross-flow duct, achieving bidirectional flipping. When the air guide plate flips upwards, a heating "carpet wind" effect can be achieved; when it flips downwards, a cooling "canopy wind" effect can be achieved. Furthermore, the clearance section can provide multiple flipping and downward pressing angles, making the air guiding range more diverse, significantly improving the airflow downward pressing effect, and effectively avoiding dead air zones, breaking through the limitation of traditional air guide plates that can only flip downwards. Further, the dimension L2 of the clearance section in the direction of the diffuser should not be too large, otherwise it will lead to airflow loss and increased noise. By setting L2 / (L1+L2) in the range of 0.5~0.75 and the arch height h in the range of 0.08~0.12 times (L1+L2), while achieving the upward flipping function of the air guide plate, the negative impact of the modification of the volute structure on the original performance of the cross-flow duct is minimized, ensuring almost no loss of airflow and noise levels. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the appearance of a wall-mounted air conditioner indoor unit according to one embodiment of the present disclosure; Figure 2 This is a front view of the indoor unit of a wall-mounted air conditioner according to one embodiment of this disclosure; Figure 3 yes Figure 2 Structural diagram omitting the air guide plate; Figure 4 yes Figure 2 Sectional view at point AA; Figure 5 yes Figure 4 Structural diagram omitting the air guide plate; Figure 6 This is a partial structural diagram of the housing according to one embodiment of the present disclosure; Figure 7 This is a schematic diagram of the structure of the air guide plate installed on the housing according to one embodiment of the present disclosure; Figures 8-10 This is a cross-sectional view of a wall-mounted air conditioner indoor unit according to one embodiment of this disclosure; Figure 11 This is a schematic diagram of the indoor unit of a wall-mounted air conditioner in heating mode according to an embodiment of this disclosure; Figure 12 This is a schematic diagram of the indoor unit of a wall-mounted air conditioner in cooling mode according to an embodiment of this disclosure; Figure 13 This is a partial cross-sectional view of the air guide plate in the closed position according to an embodiment of the present disclosure; Figure 14 This is a partial cross-sectional view of the air guide plate at its upper limit position according to an embodiment of this disclosure; Figure 15 This is a schematic diagram of the upward tilting angle of the air guide plate according to one embodiment of the present disclosure.

[0026] In the above figures: indoor unit of wall-mounted air conditioner 100; casing 10; cross-flow fan 20; indoor heat exchanger 30; air inlet 1; air outlet 2; air guide plate 3; rotating shaft 31; air guide surface 32; air inlet grille 4; volute 5; volute tongue 6; windward section 61; volute tongue section 62; diffuser section 63; transition section 631; clearance section 64; cross-flow duct 7. Detailed Implementation

[0027] The present invention will now be described in detail through exemplary embodiments. However, it should be understood that, without further description, elements, structures, and features in one embodiment may be advantageously incorporated into other embodiments.

[0028] In this utility model, the reference to "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this application may be combined with other embodiments without conflict.

[0029] In the description of this utility model, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0030] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature.

[0031] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0032] The wall-mounted air conditioner indoor unit 100 provided in this utility model embodiment can have various implementation forms, as detailed below. Figures 1-15 The indoor unit 100 of the air conditioner is described.

[0033] It should be noted that the indoor unit 100 of the wall-mounted air conditioner is part of the air conditioner. The indoor unit 100 is installed indoors and is used for heat exchange with the indoor environment. In addition, the air conditioner also includes an outdoor unit, which is usually installed outdoors and is used to carry heat from indoors to outdoors.

[0034] refer to Figures 1-3 In one illustrative embodiment of the wall-mounted air conditioner indoor unit 100 provided by this utility model, the wall-mounted air conditioner indoor unit 100 may include a housing 10. The housing 10 is installed indoors, and the housing 10 forms the overall appearance of the wall-mounted air conditioner indoor unit 100.

[0035] The housing 10 is rectangular, with the left and right ends being the two ends of the housing 10 along its own length.

[0036] The housing 10 has an internal receiving space. This receiving space is used to house and fix various components in the wall-mounted air conditioner indoor unit 100, which can prevent external objects from colliding with the various components inside the housing 10, thereby improving the reliability of the wall-mounted air conditioner indoor unit 100 during transportation or installation.

[0037] In some embodiments of this application, reference is made to Figure 1 The housing 10 may include an air inlet 1.

[0038] The air inlet 1 is connected to the housing space. The air inlet 1 serves as the entrance for external air to flow into the housing 10, allowing indoor air to enter the housing space through the air inlet 1.

[0039] In some embodiments of this application, reference is made to Figure 3 The housing 10 may include an air outlet 2.

[0040] The air outlet 2 is connected to the housing space. The air outlet 2 serves as the outlet for airflow within the housing 10, allowing airflow within the housing space to flow out through the air outlet 2.

[0041] In some embodiments of this application, the air inlet 1 is located at the top of the housing 10. The air outlet 2 may be located at the bottom front side of the housing 10.

[0042] The air outlet 2 is elongated and can extend along the length of the casing 10, improving the aesthetics of the wall-mounted air conditioner indoor unit 100. In this embodiment, when the wall-mounted air conditioner indoor unit 100 is working, it draws in air from the top and discharges air towards the bottom front, facilitating installation.

[0043] It should be noted that the directions described in the text are based on the direction in which the user faces the indoor unit 100 of the wall-mounted air conditioner. Specifically, the side of the indoor unit 100 facing the user when in use is defined as the front side, and the opposite side is defined as the rear side. The left and right sides are distinguished by the direction in which the user faces the indoor unit 100 of the wall-mounted air conditioner.

[0044] In some embodiments of this application, reference is made to Figure 4 The indoor unit 100 of the wall-mounted air conditioner may include an indoor heat exchanger 30. The indoor heat exchanger 30 extends along the length of the casing 10 and is disposed inside the casing 10 for heat exchange with the airflow inside the casing 10.

[0045] In some embodiments of this application, reference continues to be made to Figure 4 The indoor unit 100 of the wall-mounted air conditioner may include a cross-flow fan 20.

[0046] The cross-flow fan 20 is installed in the housing space and is used to drive the indoor air outside the housing 10 into the housing space inside the housing 10 through the air inlet 1. The cross-flow fan 20 drives the airflow in the housing space to flow along the air inlet 1 towards the air outlet 2.

[0047] In some embodiments of this application, the indoor heat exchanger 30 is located closer to the air inlet 1 than the cross-flow fan 20. (See reference...) Figure 4 The indoor heat exchanger 30 can be located inside the air inlet 1, and the cross-flow fan 20 is located on the leeward side of the indoor heat exchanger 30. In the airflow direction inside the casing 10, the cross-flow fan 20 is located downstream of the indoor heat exchanger 30.

[0048] When the indoor unit 100 of the wall-mounted air conditioner is running, the indoor air enters the containment space through the air inlet 1 under the rotation of the cross-flow fan 20. The indoor air in the containment space flows through the indoor heat exchanger 30 for heat exchange. The heat-exchanged airflow is discharged to the outside of the room through the air outlet 2, thereby enabling the air conditioner to cool and heat, play a role in regulating the indoor temperature, and achieve the user's comfortable temperature.

[0049] In some embodiments of this application, reference is made to Figure 1 The indoor unit 100 of the wall-mounted air conditioner may include an air inlet grille 4.

[0050] The air intake grille 4 is located at the air intake 1 to filter the air and prevent larger impurities from entering the containment space.

[0051] An outdoor unit for an air conditioner may include an outdoor unit housing. The outdoor unit housing may contain an installation cavity.

[0052] The outdoor unit housing may include an outdoor air inlet. The outdoor air inlet may communicate with the mounting cavity. The outdoor air inlet can be used to introduce outdoor air into the mounting cavity.

[0053] The outdoor unit housing may include an outdoor air outlet. The outdoor air outlet may communicate with the mounting cavity. The outdoor air outlet can be used to exhaust air from inside the mounting cavity to the outside of the mounting cavity.

[0054] An outdoor unit for an air conditioner may include an outdoor heat exchanger. The outdoor heat exchanger may be located inside an installation cavity.

[0055] An outdoor unit for an air conditioner may include an outdoor fan. The outdoor fan may be installed inside the mounting cavity.

[0056] The rotation of the outdoor fan causes outdoor air to enter the installation cavity through the outdoor air inlet and exchange heat with the outdoor heat exchanger. After heat exchange, the outdoor air flows out of the installation cavity through the outdoor air outlet.

[0057] An air conditioner may include a compressor. The compressor is located within the mounting cavity.

[0058] Air conditioners may include a throttling device. The throttling device is used to limit airflow. The throttling device may be provided in the indoor unit 100 or the outdoor unit of a wall-mounted air conditioner.

[0059] Air conditioners execute a refrigeration cycle using a compressor, condenser, throttling device, and evaporator. The refrigeration cycle involves a series of processes including compression, condensation, expansion, and evaporation, supplying refrigerant to the conditioned and heat-exchanged air.

[0060] The compressor compresses the refrigerant gas at low temperature and low pressure and discharges it at high temperature and high pressure. The discharged refrigerant gas flows into the condenser.

[0061] The condenser condenses the compressed refrigerant into a liquid phase, and the heat is released to the surrounding environment through the condensation process.

[0062] The throttling device causes the high-temperature, high-pressure liquid refrigerant condensed in the condenser to expand into a low-pressure liquid refrigerant.

[0063] The evaporator evaporates the refrigerant that expands in the throttling device and returns the refrigerant gas, which is in a low-temperature and low-pressure state, to the compressor.

[0064] An evaporator achieves a cooling effect by exchanging heat with the material being cooled using the latent heat of refrigerant evaporation. Throughout the cycle, the air conditioner regulates the temperature of the indoor space.

[0065] Of the indoor heat exchanger 30 and the outdoor heat exchanger, one is a condenser and the other is an indoor heat exchanger 30. When the indoor heat exchanger 30 is used as a condenser, the air conditioner is used as a heater in heating mode. When the indoor heat exchanger 30 is used as an indoor heat exchanger 30, the air conditioner is used as a cooler in cooling mode.

[0066] In some embodiments of this application, the housing 10 may include a volute tongue 6, which is disposed in a receiving space. The volute tongue 6 is generally tongue-shaped.

[0067] The housing 10 may include a volute 5, which is disposed in the receiving space, as shown in the reference. Figure 4 The volute 5 is located behind the volute tongue 6.

[0068] Continue to refer to Figure 4 A cross-flow duct 7 is formed between the volute 5 and the volute tongue 6, and the cross-flow duct 7 is connected to the air outlet 2. The cross-flow impeller 20 is located in the cross-flow duct 7 between the volute 5 and the volute tongue 6. With the rotation of the cross-flow impeller 20, the cross-flow duct 7 guides the heat-exchanged airflow to the air outlet 2, and the heat-exchanged airflow flows into the indoor environment through the air outlet 2.

[0069] The volute 5 forms the rear sidewall of the cross-flow duct 7, and the volute tongue 6 forms the front sidewall of the cross-flow duct 7. At the air outlet 2, the volute 5 and the volute tongue 6 are distributed on both sides of the width direction of the air outlet 2.

[0070] In some embodiments of this application, the volute tongue 6 is provided with a guide surface. (See reference...) Figure 5 In a cross section perpendicular to the axial direction of the cross-flow impeller 20, the guide surface may include the windward section 61.

[0071] refer to Figure 5 The windward section 61 is positioned facing the cross-flow impeller 20, serving as the windward surface of the volute tongue 6. Exemplarily, in this embodiment, the windward section 61 is arc-shaped. By setting the windward section 61 to an arc shape, when an eccentric vortex is generated, the airflow of the eccentric vortex can pass more smoothly through the windward section 61, reducing wind resistance.

[0072] Continue to refer to Figure 5 The airflow guiding surface may include a diffuser section 63, which is positioned close to the air outlet 2 relative to the windward section 61, in order to achieve a linear guiding effect on the airflow in the cross-flow duct 7 and avoid the problem of airflow loss at the air outlet 2 during the operation of the indoor unit 100 of the wall-mounted air conditioner.

[0073] The guide surface may include a volute tongue section 62, which connects the windward section 61 and the diffuser section 63. For example, the volute tongue section 62 may be an arc, and the diffuser section 63 and the windward section 61 are connected by an arc transition to form the volute tongue 6.

[0074] In this embodiment, on a cross section perpendicular to the axial direction of the cross-flow impeller 20, the guiding surface includes a windward section 61, a volute section 62, and a diffuser section 63 connected in sequence, with the windward section 61 being closer to the cross-flow impeller 20 than the diffuser section 63.

[0075] In some embodiments of this application, the volute tongue segment 62 is arranged in an arc shape. The arc-shaped volute tongue segment 62 makes the channel between the windward section 61 and the outer contour of the cross-flow impeller 20 smoother, and the airflow transition is more natural and smooth, thereby further improving the airflow stability of the cross-flow impeller 20.

[0076] In some embodiments of this application, reference is made to Figure 4 The indoor unit 100 of the wall-mounted air conditioner may include an air guide plate 3, which is rotatably disposed at the air outlet 2 to open or close the air outlet 2. The air guide plate 3 is rotatably connected to the casing 10.

[0077] In this embodiment, when the air outlet 2 is opened by the air guide plate 3, the air guide plate 3 is used to guide the heat exchange airflow. The air guide plate 3 with the air outlet 2 open can guide the outlet direction of the heat exchange airflow at different angles.

[0078] In some embodiments of this application, the wall-mounted air conditioner indoor unit 100 may include a drive device (not shown), which is mounted on the housing 10. The drive device is connected to the air guide plate 3 and is used to drive the air guide plate 3 to rotate in two directions.

[0079] In this embodiment, the driving device can drive the air guide plate 3 to rotate bidirectionally along the rotation axis to achieve multiple air supply modes such as cooling "sky curtain wind" and heating "carpet wind", avoiding cold air blowing directly on the human body and expanding the air supply range.

[0080] To enable the air guide plate 3 to rotate bidirectionally along the rotation axis, in some embodiments of this application, the wall-mounted air conditioner indoor unit 100 may include a clearance portion 64. (See reference...) Figures 5-7 The clearance section 64 is formed by a recess in the diffuser section 63 in a direction away from the volute 5. The clearance section 64 is used to avoid the air guide plate 3 that rotates into the cross-flow duct 7.

[0081] In this embodiment, by providing a recessed clearance portion 64, the air guide plate 3 can be flipped upwards and embedded into the cross-flow duct 7, achieving bidirectional flipping. (Reference) Figure 11 When the air guide plate 3 is flipped upwards, a "carpet breeze" heating effect can be achieved. (Reference) Figure 12When the air guide plate 3 is flipped down, it can achieve a cooling "sky curtain wind" effect. In addition, the avoidance part 64 can also provide a variety of flipping and pressing angles, making the air guiding range more diversified, significantly improving the airflow pressing effect, and effectively avoiding air delivery dead angles, breaking through the limitation of the traditional air guide plate 3 being able to only flip down.

[0082] In some embodiments of this application, reference is made to Figure 8 The portion of the diffuser section 63 located between the clearance section 64 and the volute tongue section 62 is defined as the transition section 631. The size of the transition section 631 is L1. The size L2 of the clearance section 64 in the extension direction of the transition section 631 satisfies: L2 / (L1+L2)≤0.75, L2 / (L1+L2)≥0.5.

[0083] The size ratio of the clearance section needs to be strictly controlled. If the ratio of L2 to (L1+L2) is too large, it means that the clearance section 64 occupies too high a proportion in the upper profile of the volute tongue 6 and is too close to the volute tongue section 62. This will cause the airflow to separate too early when it passes through this area and will not be able to adhere to the wall surface, thus generating strong vortices, resulting in significant loss of air volume and increased noise. Conversely, if the ratio of L2 to (L1+L2) is too small, it means that the space provided by the clearance section is insufficient, which will not meet the movement stroke required for the wind deflector to effectively flip upward, thus limiting its flipping function.

[0084] refer to Figure 9 The arch height h of the clearance section 64 satisfies: h≥0.08(L1+L2), h≤0.12(L1+L2).

[0085] If the arch height h of the clearance section is greater than 0.12(L1+L2), it means that the protrusion height of the clearance section 64 is too high. Although it can meet the clearance requirements of the air guide plate 3 to a certain extent, it will excessively damage the air duct structure and severely weaken the guiding effect of the guide surface. The excessively high protrusion will severely disrupt the originally stable airflow, causing it to separate severely at the apex of the clearance section, generating large-scale vortices, significantly increasing flow resistance and pressure loss, and even inducing abnormal noise in the cavity, resulting in a significant decrease in the outlet air volume and a significant increase in operating noise.

[0086] If the arch height h of the clearance section is less than 0.08(L1+L2), the protrusion height is insufficient, the clearance section is too shallow and flat, and it cannot provide enough storage space for the air guide plate 3. During the upward flipping process of the air guide plate 3, its front end will mechanically interfere with the wall of the cross-flow duct, resulting in the inability to reach the preset upward flipping angle. As a result, the heat exchange airflow during heating cannot be effectively guided to the ground, ultimately causing the upward flipping air supply function to fail.

[0087] In this embodiment, by setting the arch height h between 0.08(L1+L2) and 0.12(L1+L2), and setting L2 / (L1+L2) between 0.5 and 0.75, it is ensured that the clearance part 64 has a sufficiently large space (determined by h and L2) to reliably accommodate the upward-turned air guide plate, while not excessively damaging the profile of the upper wall of the air duct, avoiding serious airflow separation and vortex generation, minimizing the negative impact of the modification of the volute tongue structure on the original performance of the cross-flow air duct, and ensuring that there is almost no loss in air volume and noise indicators.

[0088] In some other embodiments, the volute tongue 6 may include a windward portion, a volute tongue portion, and a diffuser portion connected in sequence, with the windward portion positioned relative to the diffuser portion and close to the cross-flow impeller 20. The volute tongue 6 may also include a clearance portion 64, which is connected to the end of the diffuser portion furthest from the cross-flow impeller 20.

[0089] The clearance portion 64 is recessed relative to the diffuser portion in a direction away from the volute 5 to avoid the air guide plate 3 rotating into the cross-flow duct 7. In a cross section perpendicular to the axial direction of the cross-flow impeller 20, the dimension of the diffuser portion in its own extension direction is L1, and the dimension L2 of the clearance portion 64 in the extension direction of the diffuser portion satisfies: L2 / (L1+L2)≤0.75, L2 / (L1+L2)≥0.5; the arch height h of the clearance portion 64 satisfies: h≥0.08(L1+L2), h≤0.12(L1+L2). While achieving the above-mentioned functions of the air guide plate 3, the negative impact on the original performance of the cross-flow duct 7 is minimized, ensuring that there is almost no loss in air volume and noise levels.

[0090] In some embodiments of this application, reference continues to be made to Figure 8 The radius of the cochlear tongue segment 62 is R1, and L1 satisfies: L1 > 1.5R1.

[0091] The transition section 631 provides a stable and smooth transition channel for the high-speed airflow exiting the volute tongue section 62, allowing it to fully adhere to and accelerate towards the outlet 2. Therefore, L1 cannot be too small. If it is too small, the transition section 631 will be too short, affecting the guiding effect of the volute tongue section 62. At the same time, if L1 is too small, the airflow will encounter the avoidance part 64 too early, resulting in airflow separation, generating huge vortices, and affecting the stability of the airflow.

[0092] If L1≤1.5R1, then the transition section 631 is too short, which will affect the airflow guiding effect at the volute tongue section 62, leading to airflow reduction or even unstable airflow.

[0093] In this embodiment, by setting the size L1 of the transition section 631 to be greater than 1.5R1, the transition length between the volute tongue section 62 and the clearance section 64 is ensured to be sufficiently long, allowing the airflow to have enough distance to re-stabilize and reattach after passing through the volute tongue section 62. When this stable heat exchange airflow encounters the clearance section 64, its anti-interference ability is stronger, and it can better follow the Coanda effect, flowing along the inner wall of the clearance section 64, thereby minimizing airflow disturbance and separation, ensuring airflow volume and reducing noise, thus achieving better duct performance.

[0094] In some embodiments of this application, the radius of the cochlear tongue segment 62 is R1, and L1 satisfies: L1 > 2.0R1.

[0095] By setting L to be greater than 2.0R1, compared to embodiments with L greater than 1.5R1, the longer transition section 631 provides a more sufficient stabilization distance for the airflow, ensuring that it is in optimal flow condition before reaching the avoidance section 64. L1 > 2.0R1 minimizes the disturbance of the airflow by the avoidance section 64, resulting in minimal airflow loss, extremely low airflow attenuation, smooth airflow, fewer eddies, and better noise performance.

[0096] In some embodiments of this application, the avoidance portion 64 is arranged in an arc.

[0097] In this embodiment, the arc-shaped clearance portion 64 can match the arc-shaped movement trajectory of the air guide plate 3 during its flipping motion, reducing the risk of mechanical interference when the air guide plate 3 flips. At the same time, the arc-shaped clearance portion 64 is easy to manufacture and its aerodynamic characteristics are relatively mature, which is conducive to guiding the airflow smoothly, reducing airflow impact noise, and avoiding the degradation of air duct performance.

[0098] In some embodiments of this application, reference is made to Figure 9 The radius of the clearance part 64 is R2, and the outer diameter of the cross-flow impeller 20 is D2, wherein R2 satisfies: R2≤0.55D2, R2≥0.45D2.

[0099] It should be noted that the outer diameter of the cross-flow wind turbine 20 is the distance from the outer edge of the blades of the cross-flow wind turbine 20 to the axis of rotation of the cross-flow wind turbine 20.

[0100] When the clearance part 64 is arc-shaped, under the same chord length L2, the larger the radius R2, the smaller the recess depth of the clearance part 64.

[0101] If R2 > 0.55D2, the recess of the avoidance part 64 is relatively gentle and cannot provide effective avoidance space for the air guide plate 3 to flip upward. When the air guide plate 3 flips upward, it will directly hit the front side wall of the cross-flow duct 7, making it unable to achieve its core function of flipping upward into the cross-flow duct 7. The upward angle is limited, affecting the air delivery range and air delivery effect of the heated carpet.

[0102] If R2 < 0.45D2, the indentation of the clearance section 64 is too steep, the local diffusion angle increases sharply, the airflow is prone to form vortices in the clearance section 64, the cavity sound is obvious, and the overall noise of the machine increases.

[0103] In this embodiment, by associating the radius R2 of the avoidance section 64 with the outer diameter of the cross-flow impeller 20, and setting the radius R2 within the range of 0.45D2 to 0.55D2, it is ensured that it provides sufficient space to avoid the air guide plate 3 without excessively damaging the duct structure due to excessive curvature, thus achieving a balance between avoidance function and duct performance. The aforementioned radius R2 range ensures that the shape of the avoidance section 64 is always kept in the optimal range of "lowest vortex shedding, no airflow attenuation, and large rotation angle," maximizing the preservation of duct performance advantages.

[0104] In some embodiments of this application, reference is made to Figure 10 The central angle α corresponding to the avoidance part 64 satisfies: α≥55°, α≤65°.

[0105] If α > 65°, the opening of the avoidance section 64 will be too large, excessively encroaching on the length of the diffuser section 63, causing the outlet airflow of the volute tongue section 62 to suddenly diffuse and the air volume to decrease significantly. At the same time, the airflow is prone to form a large-scale and stable backflow vortex region in the avoidance section 64. The violent airflow separation and vortex disturbance will generate significant vortex noise, and the noise of the whole machine will increase sharply.

[0106] If α < 55°, the opening of the avoidance part 64 is too small, the avoidance space of the avoidance part 64 is insufficient, most of the air guide plate 3 is still exposed outside the cross-flow air duct 7, the upward limit angle is reduced accordingly, and it cannot be flipped upward to the expected limit position, which in turn leads to insufficient downward pressure angle of the "carpet wind" when heating, causing the carpet wind air supply mode to fail or its effect to be greatly reduced.

[0107] In this embodiment, by setting the central angle α within the range of 55° to 65°, the opening angle of the avoidance part 64 is matched with the flipping trajectory of the air guide plate 3. This ensures that the air guide plate 3 flips up to the cross-flow duct 7 to obtain a larger expected flipping angle, while also ensuring a smooth transition of the airflow boundary layer. The air volume, noise, and structural strength are all in the optimal range at the same time, thereby achieving better duct performance.

[0108] It should be noted that in the cross section perpendicular to the axis of the cross-flow wind turbine 20, the vertical distance between the arc chord of the clearance part 64 and the apex of the arc is the arch height h.

[0109] In some embodiments of this application, the air guide plate 3 has a closed position that closes the air outlet 2 (e.g. Figure 13 As shown), and flipped upwards to the upper limit position (as shown). Figure 14 (As shown). The air guide plate 3 is rotatably connected to the housing 10 via a rotating shaft 31.

[0110] It should be noted that in this embodiment, the closed position is the initial position of the indoor unit 100 of the wall-mounted air conditioner when it is turned off. (Reference) Figure 13 On a cross section perpendicular to the axial direction of the cross-flow impeller 20, at this position, the angle between the line connecting the bottom end of the guide surface 32 and the rotation axis of the guide plate and the horizontal plane is a preset angle α.

[0111] The angle β through which the air guide plate 3 rotates from the closed position to the upper limit position satisfies: β≥65°, β≤115°, which can provide a very wide stepless adjustment space. Within this angle range, the most suitable downward pressure angle can be selected to achieve multi-angle heating carpet air, making the air delivery more precise and user-friendly.

[0112] refer to Figure 15 The air guide plate 3 is provided with an air guide surface 32, which is the side of the air guide plate 3 facing the cross-flow duct 7 when it is in the closed position. In the closed position, the bottom end of the air guide surface 32 is point A, and in the upper limit position, the air outlet end of the air guide surface 32 is point B. The angle formed by points A and B and the rotation axis is the aforementioned angle β.

[0113] It should be noted that the upper limit position of the air guide plate 3 is the position where the air guide plate 3 can no longer rotate in the upward direction.

[0114] If the included angle β < 65°, the upward tilt angle of the air guide plate 3 will be limited, greatly reducing the adjustable range of the air supply angle and affecting the air supply range and effect of the air conditioner during heating.

[0115] If the included angle β > 115°, the upward tilt angle of the air guide plate 3 will be larger. The larger the upward tilt angle, the greater the air volume loss, which will affect the performance of the air duct.

[0116] In this embodiment, β ≥ 65° ensures that in heating mode, the air guide plate 3 can flip upwards to a sufficient angle, thereby giving the exhaust airflow a clear and sufficient downward component to force the hot exhaust air to be directed to the ground, forming an effective carpet breeze. This solves the problem of hot air suspension during heating, significantly improving comfort and energy efficiency. It also enables multi-angle heated carpet breezes. β ≤ 115° not only ensures that the air guide plate 3 can smoothly flip upwards into the cross-flow duct 7, maintaining the basic duct performance and avoiding excessive airflow loss.

[0117] In some embodiments of this application, the air guide plate 3 can be an arc-shaped plate. The arc shape of the air guide plate 3 allows it to cooperate with the arc-shaped clearance portion 64, which can improve the guiding effect of airflow and help improve air delivery efficiency and noise reduction.

[0118] The straight-line distance K between the leading and trailing edges of the air guide plate 3 satisfies: K ≤ 1.5L², K ≥ L². The center of rotation of the air guide plate 3 lies on the perpendicular bisector of the line connecting the leading and trailing edges. (Reference) Figure 14 The straight-line distance K between the front and rear edges of the air guide plate 3 is the chord length of the air guide plate 3.

[0119] If K < L2, the air guide plate 3 is too short, which not only fails to make full use of the clearance space provided by the clearance part 64, limiting its actual upward flipping effect and air delivery angle, but also affects the aesthetic appearance.

[0120] If K > 1.5L2, it means that the air guide plate 3 is too long. When the air guide plate 3 and the avoidance part 64 are flipped up, they will collide or get stuck. In addition, the rotational inertia is large, which puts high demands on the motor in the drive device.

[0121] In this embodiment, by limiting the ratio of the chord length K of the air guide plate 3 to the chord length L2 of the clearance part 64, such that K≤1.5L2 and K≥L2, the optimal geometric fit between the air guide plate 3 and the clearance part 64 is achieved, ensuring that the air guide plate 3 can be smoothly embedded into the clearance part 64, while also ensuring that the size of the air guide plate 3 is large enough to effectively guide the airflow.

[0122] In some embodiments of this application, the size of the transition segment is L1, which satisfies: L1≤0.5K.

[0123] Under the constraint of a relatively fixed upper profile of the entire cross-flow duct, if L1 > 0.5K, it will directly cause L2 corresponding to the avoidance part 64 to be compressed accordingly, resulting in insufficient avoidance space for the air guide plate 3 to flip up. This will restrict the movement trajectory of the air guide plate 3, preventing it from rotating to the preset limit position, thereby reducing the upper limit angle of the air guide plate 3 and ultimately weakening the function of achieving large-angle "carpet wind" air delivery.

[0124] In this embodiment, by setting L1≤0.5K, it is indirectly ensured that the path of airflow from the volute tongue section 62 to the air outlet 2 will not cause unnecessary diffusion or energy loss due to the excessive length of the transition section 631. This helps to maintain the adhesion and directionality of the airflow. At the same time, it enables the avoidance section 64 to provide reliable and sufficient avoidance space, ensuring the functionality of core air supply modes such as "carpet wind".

[0125] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

[0126] For ease of explanation, the above description has been provided in conjunction with specific embodiments. However, the above exemplary discussion is not intended to be exhaustive or to limit the embodiments to the specific forms disclosed above. Various modifications and variations can be obtained based on the above teachings. The selection and description of the above embodiments are for the purpose of better explaining the principles and practical applications, thereby enabling those skilled in the art to better utilize the described embodiments and various different variations of embodiments suitable for specific use considerations.

Claims

1. A wall-mounted air conditioner indoor unit, characterized in that, include: The housing includes a volute tongue and a volute shell, a cross-flow air duct is formed between the volute tongue and the volute shell, and the housing includes an air outlet connected to the cross-flow air duct, the air outlet being located at the bottom front side of the housing. An indoor heat exchanger is located in the casing and exchanges heat with the air inside the casing. A cross-flow fan is disposed in the cross-flow duct. Under the rotation of the cross-flow fan, the cross-flow duct guides the heat-exchanged airflow to the air outlet. An air guide plate is rotatably disposed at the air outlet to open or close the air outlet; A drive device is mounted on the housing and connected to the air guide plate to drive the air guide plate to rotate in two directions; The volute tongue is provided with a guide surface. On a cross section perpendicular to the axial direction of the cross-flow impeller, the guide surface includes a windward section, a volute tongue section, and a diffuser section connected in sequence. The windward section is closer to the cross-flow impeller than the diffuser section. The clearance section is formed by a portion of the diffuser section that is recessed away from the volute, and is used to clear the air guide plate that rotates into the cross-flow duct. The portion of the diffuser section located between the clearance section and the volute tongue section is defined as the transition section. The size of the transition section is L1. The size L2 of the clearance section in the extension direction of the transition section satisfies: L2 / (L1+L2)≤0.75, L2 / (L1+L2)≥0.5; the arch height h of the clearance section satisfies: h≥0.08(L1+L2), h≤0.12(L1+L2).

2. The wall-mounted air conditioner indoor unit according to claim 1, characterized in that, The volute tongue segment is arc-shaped, and the radius of the volute tongue segment is R1, where L1 satisfies: L1 > 1.5R1.

3. The wall-mounted air conditioner indoor unit according to claim 1, characterized in that, The avoidance section is arranged in an arc shape.

4. The wall-mounted air conditioner indoor unit according to claim 3, characterized in that, The radius of the avoidance part is R2, and the outer diameter of the cross-flow wind turbine is D2. R2 satisfies: R2≤0.55D2, R2≥0.45D2.

5. The wall-mounted air conditioner indoor unit according to claim 3, characterized in that, The central angle α corresponding to the avoidance part satisfies: α≥55°, α≤65°.

6. The wall-mounted air conditioner indoor unit according to claim 1, characterized in that, The air guide plate has a closed position that closes the air outlet and an upper limit position that flips upward to the limit. The angle β through which the air guide plate rotates from the closed position to the upper limit position satisfies: β≥65°, β≤115°.

7. The wall-mounted air conditioner indoor unit according to claim 1, characterized in that, The air guide plate is an arc-shaped plate.

8. The wall-mounted air conditioner indoor unit according to any one of claims 1 to 7, characterized in that, The straight-line distance K between the front and rear edges of the air guide plate satisfies: K≤1.5L2, K≥L2; wherein, the rotation center of the air guide plate is located on the perpendicular bisector of the line connecting the front and rear edges.

9. The wall-mounted air conditioner indoor unit according to claim 8, characterized in that, L1 satisfies: L1≤0.5K.

10. A wall-mounted air conditioner indoor unit, characterized in that, include: The housing includes a volute tongue and a volute shell, a cross-flow air duct is formed between the volute tongue and the volute shell, and the housing includes an air outlet connected to the cross-flow air duct, the air outlet being located at the bottom front side of the housing. An indoor heat exchanger is located in the casing and exchanges heat with the air inside the casing. A cross-flow fan is disposed in the cross-flow duct. Under the rotation of the cross-flow fan, the cross-flow duct guides the heat-exchanged airflow to the air outlet. An air guide plate is rotatably disposed at the air outlet to open or close the air outlet; A drive device is mounted on the housing and connected to the air guide plate to drive the air guide plate to rotate in two directions; The volute tongue includes a windward section, a volute tongue portion, and a diffuser portion connected in sequence. The windward section is disposed near the cross-flow impeller relative to the diffuser portion. The volute tongue portion further includes: A clearance portion is connected to the end of the diffuser that is away from the cross-flow impeller. The clearance portion is recessed relative to the diffuser and is formed in a direction away from the volute. It is used to clear the air guide plate that rotates into the cross-flow duct. In a cross section perpendicular to the axial direction of the cross-flow impeller, the dimension of the diffuser in its own extension direction is L1, and the dimension L2 of the clearance part in the extension direction of the diffuser satisfies: L2 / (L1+L2)≤0.75, L2 / (L1+L2)≥0.5; the arch height h of the clearance part satisfies: h≥0.08(L1+L2), h≤0.12(L1+L2).

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