Embedded air conditioner indoor unit and embedded air conditioner

Abstract

The invention relates to the technical field of electric appliances, particularly provides an indoor unit of an embedded air conditioner and the embedded air conditioner, and aims to solve the problems of insufficient air volume, non-uniform air flow distribution and high operation noise caused by unreasonable distance design between an air outlet of a centrifugal fan and a heat exchanger. Therefore, the embedded air conditioner indoor unit comprises a shell, a centrifugal fan and a heat exchanger, the centrifugal fan and the heat exchanger are located in the shell and perpendicularly installed on a bottom plate of the shell, the heat exchanger surrounds the centrifugal fan in the circumferential direction of the centrifugal fan, and the heat exchanger and an air outlet of the centrifugal fan are oppositely arranged; the shortest distance L1 is formed between at least one position of the heat exchanger and the air outlet, D1 is larger than or equal to 0.74 L1 and smaller than or equal to 0.78 L1, and D1 is the diameter of the centrifugal fan. Therefore, the high-speed airflow blown by the fan can be uniformly and stably blown to the surface of the heat exchanger at enough dynamic pressure, so that the total air quantity penetrating through the heat exchanger is obviously increased, and the aerodynamic noise is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electrical appliances, and particularly provides an embedded air conditioner indoor unit and an embedded air conditioner. BACKGROUND

[0002] In the field of commercial and residential buildings, ceiling embedded air conditioners (referred to as embedded machines) have become the mainstream air conditioning form in supermarkets, office buildings, shops and other places with high floor height due to their concealed installation, high efficiency of refrigeration and heating, and wide range of air conditioning capacity. Such products drive indoor air circulation through centrifugal fan blades: after the air flow is worked by the centrifugal fan blades, it is first discharged from the blade outlet along the vertical direction (90° turn), flows through the indoor heat exchanger for heat exchange, and is then blown out through the air outlet flow channel after a second 90° turn, thereby finally achieving temperature regulation of the indoor environment.

[0003] However, there is a key performance bottleneck in the prior art: the installation distance between the centrifugal fan outlet and the heat exchanger has a significant impact on the system air volume, air flow uniformity and operating noise. Specifically, when the distance between the two is too small, the air flow cannot be fully diffused, resulting in uneven distribution of wind speed on the surface of the heat exchanger, insufficient air volume in local areas, and reduced heat exchange efficiency; when the distance is too large, the air flow is prone to boundary layer separation or vortex during flow, which not only increases the wind resistance loss and reduces the air volume, but also causes abnormal noise due to turbulent air flow.

[0004] Therefore, there is a need in the art for a new technical solution to solve the above problems. SUMMARY

[0005] The present application aims to solve the above technical problems, i.e., to solve the problems of insufficient air volume, uneven air flow distribution and high operating noise caused by the unreasonable design of the distance between the centrifugal fan outlet and the heat exchanger in the existing ceiling embedded air conditioner.

[0006] In a first aspect, the present application provides an embedded air conditioner indoor unit, comprising a shell, a centrifugal fan and a heat exchanger located in the shell and vertically installed on the bottom plate of the shell, the heat exchanger surrounds the centrifugal fan along the circumference of the centrifugal fan, and the heat exchanger is arranged opposite to the air outlet of the centrifugal fan, and the heat exchanger has at least one shortest distance L1 from the air outlet, 0.74L1≤D1≤0.78L1, wherein D1 is the diameter of the centrifugal fan.

[0007] In the preferred technical solution of the above embedded air conditioner indoor unit, the heat exchanger has a rectangular shape, the heat exchanger has dimensions L2 and L3 along a first direction and a second direction respectively, and L2≥L3, 0.74L3≤D1≤0.78L3, and the first direction is perpendicular to the second direction.

[0008] In the preferred technical scheme of the embedded air conditioner indoor unit, the centrifugal fan comprises a wheel cover and a fan wheel disc arranged oppositely in the vertical direction, a plurality of blades are arranged between the wheel cover and the fan wheel disc, the plurality of blades are distributed along the circumference of the fan wheel disc, an air inlet is formed in the wheel cover, the diameter of the air inlet is D2, and 0.78D1≤D2≤0.8D1.

[0009] In the preferred technical scheme of the embedded air conditioner indoor unit, the height of the heat exchanger is H1, the vertical height between the outer side surface of the wheel cover and the outer side surface of the fan wheel disc is H2, and 0.67H1≤H2≤0.71H1.

[0010] In the preferred technical scheme of the embedded air conditioner indoor unit, the wheel cover comprises a ring-shaped base body and a wind guide part arranged at the edge of the ring-shaped base body along the circumference of the ring-shaped base body, the ring-shaped base body has the air inlet in the middle, the wind guide part overlaps the blades in the vertical direction, along the radial direction of the ring-shaped base body, the connecting line of the two ends of the wind guide part forms a preset included angle with the horizontal plane on which the ring-shaped base body is located, the vertical height between the end of the wind guide part away from the ring-shaped base body and the fan wheel disc is the air outlet height H3 of the air outlet, and 0.71H2≤H3≤0.75H2.

[0011] In the preferred technical scheme of the embedded air conditioner indoor unit, the blades comprise a leading edge and a trailing edge, the leading edge is used for introducing external air between the plurality of blades, the trailing edge is used for discharging air between the plurality of blades,

[0012] In the preferred technical scheme of the embedded air conditioner indoor unit, among the two adjacent blades, the windward surface of one blade has an outlet characteristic line from top to bottom, the outlet characteristic line is formed by connecting the points on the windward surface of the blade closest to the trailing edge of the adjacent blade, the trailing edge of the blade corresponds to the position of the outlet characteristic line of the adjacent blade, and the two form the air outlet of the centrifugal fan, and the width of the air outlet decreases first and then increases from top to bottom.

[0013] In the preferred technical scheme of the embedded air conditioner indoor unit, among the two adjacent blades, the trailing edge of one blade comprises a first segment and a second segment distributed from top to bottom, the first segment is inclined from top to bottom towards the windward side of the blade, the second segment is inclined from top to bottom towards the leeward side of the blade, the outlet characteristic line of the other blade is curved into an arc from top to bottom towards the windward side, the first segment has a first feature point P1, the width of the air outlet at the first feature point P1 is the smallest, and the width of the top end of the air outlet is smaller than the width of the bottom end of the air outlet.

[0014] In the preferred technical scheme of the embedded air conditioner indoor unit, the first section further has a second feature point P2, the second feature point P2 is located above the first feature point P1, the second feature point P2 and the first feature point P1 divide the first section from top to bottom into a first sub-segment, a second sub-segment and a third sub-segment, and the inclination of the first sub-segment, the second sub-segment and the third sub-segment increases in turn.

[0015] In the preferred technical scheme of the embedded air conditioner indoor unit, from the top end of the leading edge to the bottom end of the leading edge, the leading edge is in an arc shape with a gradually increasing tangent slope, and / or

[0016] The leading edge is inclined towards the leeward side of the blade.

[0017] In the second aspect, the application provides an embedded air conditioner, comprising an outdoor unit and the embedded air conditioner indoor unit described in any one of the above, the outdoor unit is connected with the embedded air conditioner indoor unit.

[0018] As can be understood by those skilled in the art, the technical scheme of the application provides an embedded air conditioner indoor unit. In the case of using the above technical scheme, the application can solve the problems of insufficient air volume, uneven airflow distribution and large operating noise caused by unreasonable design of the distance between the centrifugal fan outlet and the heat exchanger. Specifically, by accurately controlling D1 within the range of 0.74L1 to 0.78L1, it is ensured that the high-speed airflow blown by the fan is neither excessively diffused (losing kinetic energy) nor excessively limited (increasing resistance) when reaching the surface of the heat exchanger, and the airflow can maintain sufficient dynamic pressure and speed, efficiently and smoothly penetrating the fin gap of the heat exchanger, maximizing the effective ventilation cross-sectional area, thereby significantly increasing the total air volume passing through the heat exchanger; in addition, uniform and stable airflow reduces airflow separation, thereby avoiding the aerodynamic noise caused by high-speed airflow impacting the nearby surface or forcibly passing through the extremely narrow gap.

[0019] Further, the shape of the heat exchanger is rectangular, the dimensions of the heat exchanger along the first direction and the second direction are L2 and L3 respectively, and L2≥L3, 0.74L3≤D1≤0.78L3, the first direction is perpendicular to the second direction. By this setting, the uniformity of airflow distribution around the entire heat exchanger is improved, so that the airflow is not blocked in the short side and not separated in the long side, and the sharp noise and severe vortex shedding noise caused by the direct high-speed airflow impacting the nearby heat exchanger surface are avoided.

[0020] Further, the centrifugal fan of the present application comprises a wheel cover and a fan wheel arranged opposite to each other in the vertical direction, a plurality of blades being arranged between the wheel cover and the fan wheel, the plurality of blades being distributed along the circumference of the fan wheel, the wheel cover being provided with an air inlet, the diameter of the air inlet being D2, 0.78D1≤D2≤0.8D1. Through the above arrangement, a large enough air inlet area is ensured to minimize the air inlet resistance, allowing sufficient air flow to smoothly enter between the blades, and the air suction capacity of the centrifugal fan is significantly improved. BRIEF DESCRIPTION OF DRAWINGS

[0021] The preferred embodiments of the present application will be described below with reference to the accompanying drawings, in which:

[0022] Figure 1 is a structural schematic diagram of the indoor unit of the embedded air conditioner of the present application;

[0023] Figure 2 is a sectional view of the indoor unit of the embedded air conditioner of the present application;

[0024] Figure 3 is a structural schematic diagram of the centrifugal fan of the present application;

[0025] Figure 4 is a front view of the centrifugal fan of the present application;

[0026] Figure 5 is a schematic diagram of the position relationship between the trailing edge and the outlet characteristic line of the present application.

[0027] LIST OF REFERENCE NUMERALS

[0028] 1, housing;

[0029] 2, heat exchanger;

[0030] 3, centrifugal fan; 31, wheel cover; 311, annular base body; 312, air guide part; 32, fan wheel; 33, blade; 331, leading edge; 332, trailing edge; 3321, first section; 3322, second section; 333, outlet characteristic line; 34, air outlet; 35, air inlet. DETAILED DESCRIPTION

[0031] The preferred embodiments of the present application will be described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present application, and are not intended to limit the protection scope of the present application. For example, although the following embodiments are introduced in combination with the embedded air conditioner, the provided indoor unit of the embedded air conditioner of the present application is also applicable to other products which need to solve the problems of insufficient air volume, uneven air flow distribution and large operation noise caused by the unreasonable design of the distance between the outlet of the centrifugal fan and the heat exchanger.

[0032] It should be noted that in the description of the present application, unless otherwise expressly specified and limited, the terms "arrangement", "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integral connection. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0033] Based on the problems of insufficient air volume, uneven airflow distribution and large running noise caused by unreasonable spacing between the centrifugal fan outlet and the heat exchanger of the existing ceiling embedded air conditioner pointed out in the background art. The present application provides an embedded air conditioner indoor unit, which aims to effectively solve the problems of insufficient air volume, uneven airflow distribution and large running noise caused by unreasonable spacing between the centrifugal fan outlet and the heat exchanger by reasonably setting the spacing between the centrifugal fan outlet and the heat exchanger.

[0034] As shown in Figure 1 The present application provides an embedded air conditioner indoor unit, which comprises a shell 1, a centrifugal fan 3 and a heat exchanger 2 located in the shell 1 and vertically installed on the bottom plate of the shell 1, the heat exchanger 2 surrounds the centrifugal fan 3 along the circumference of the centrifugal fan 3, and the heat exchanger 2 is arranged opposite to the outlet 34 of the centrifugal fan 3, and the heat exchanger 2 has at least one shortest spacing L1 with the outlet 34, 0.74L1≤D1≤0.78L1, wherein D1 is the diameter of the centrifugal fan 3.

[0035] In the traditional design, if the minimum spacing (L1) between the centrifugal fan outlet 34 and the surrounding heat exchanger 2 and the fan diameter (D1) is too large, the airflow blown by the fan will be excessively diffused before reaching the heat exchanger 2, the dynamic pressure loss will be too large, the airflow velocity will be significantly reduced, and the effective air volume passing through the heat exchanger 2 will be reduced; if the above spacing is too small, the airflow passage is too narrow, the flow resistance increases sharply, which also limits the air volume, and the fan needs more power to push the same air volume, which is low in efficiency.

[0036] In addition, if the spacing is unreasonable, the airflow will separate, swirl or deviate when entering the fin channel of the heat exchanger 2. The airflow velocity in some areas is too high, while in other areas, low-speed areas or dead zones may be formed. This not only reduces the overall heat exchange efficiency, but also causes problems such as uneven temperature at the outlet 34, turbulent noise, etc.

[0037] The present application precisely controls D1 within the range of 0.74L1 to 0.78L1, which ensures that the high-speed airflow blown by the fan is neither excessively diffused (losing kinetic energy) nor excessively limited (increasing resistance) when reaching the surface of the heat exchanger 2, the airflow can maintain sufficient dynamic pressure and velocity, efficiently and smoothly penetrate the fin gap of the heat exchanger 2, maximize the effective ventilation cross-sectional area, thereby significantly increasing the total air volume passing through the heat exchanger 2. Under the same fan power, more air can be delivered.

[0038] In addition, at this optimized distance, the air flow can be more uniform and smooth to the surface of the surrounding heat exchanger 2, reducing the occurrence of air flow separation, vortex and deviation, so that the fin gap of each part of the heat exchanger 2 can obtain relatively uniform air flow, so that the area of the heat exchanger 2 can be more fully utilized, and the heat exchange between the air and the refrigerant is more uniform and efficient, thereby improving the refrigeration / heating capacity and energy efficiency ratio of the air conditioner.

[0039] Further, uniform and smooth air flow reduces air flow separation, thereby avoiding the aerodynamic noise caused by high-speed impact on the surface or forced through the extremely narrow gap (outlet chamber between the heat exchanger 2 and the centrifugal fan 3).

[0040] Preferably, as shown in the drawings, the shape of the heat exchanger 2 is rectangular, the dimensions of the heat exchanger 2 along the first direction and the second direction are L2 and L3 respectively, and L2≥L3, 0.74L3≤D1≤0.78L3, the first direction is perpendicular to the second direction. Figure 1 Since the short side (L3) is closer to the fan, the air flow diffusion distance is short, the kinetic energy loss is small, and the air flow passage is narrower. Therefore, the short side area is the area most prone to high flow rate impact, turbulent noise, and air flow obstruction.

[0041] The present application ensures that in the short side direction where the space is the most cramped and the air flow speed is the highest, the fan diameter and the air flow passage width are optimally matched by precisely controlling D1 within the range of 0.74L3 to 0.78L3, ensuring that the air flow in this area can pass smoothly without being excessively limited or impacted too strongly.

[0042] In addition, since L2≥L3, the space in the long side direction (L2) is naturally more relaxed than that in the short side direction (L3). After optimizing the short side, the space in the long side direction (L2) must be greater than that in the optimized short side direction, which means that the air flow passage in the long side direction is wide enough and the air flow diffusion and flow resistance problems are relatively small. Thus, after the air flow is uniformly blown out from the centrifugal fan 3, a relatively reasonable and balanced flow state can be obtained in both the long side and short side directions of the rectangle, greatly improving the uniformity of the air flow distribution around the entire heat exchanger 2 (the four sides of the rectangle), so that the air flow is not blocked in the short side and not separated in the long side.

[0043] Further, since the high flow rate air flow impact and turbulence in the short side area are one of the main noise sources, the present application can prevent the distance from being too small to avoid sharp noise and violent vortex shedding noise caused by high-speed impact of the air flow directly on the nearby heat exchanger 2 surface, and can also prevent the distance from being relatively too large to avoid excessive dynamic pressure loss due to too fast diffusion.

[0044]

[0045] ​Preferably, as shown in Figures 2 to 4 The centrifugal fan 3 comprises a wheel cover 31 and a fan wheel disc 32 arranged opposite in the vertical direction, a plurality of blades 33 are arranged between the wheel cover 31 and the fan wheel disc 32, the plurality of blades 33 are distributed along the circumference of the fan wheel disc 32, and an air inlet 35 is formed in the wheel cover 31, the diameter of the air inlet 35 is D2, and 0.78D1≤D2≤0.8D1.

[0046] If the air inlet 35 is too small (D2 is too small), the flow area of the air entering the impeller is limited, the air intake resistance is increased, the amount of air sucked is insufficient, and finally the total air volume is limited; if the air inlet 35 is too large (D2 is too large), air flow separation is easy to occur at the root of the blade 33 (the end of the blade 33 connected with the fan wheel disc 32), vortex is formed, flow loss and noise are increased, and efficiency and air volume are also reduced.

[0047] The diameter D2 of the air inlet 35 is accurately controlled in the range of 0.78D1 to 0.80D1, which ensures a large enough air inlet area to minimize air intake resistance, allows sufficient air flow to smoothly enter between the blades 33, while avoiding the negative effects caused by the air inlet 35 being too large, so that the air flow entering the impeller can be more smoothly and more closely guided to the root of the blade 33, creating good starting conditions for the air flow to be effectively accelerated and thrown out in the impeller, thereby significantly improving the air suction capacity of the centrifugal fan 3.

[0048] The diameter D2 of the air inlet 35 is accurately controlled in the range of 0.78D1 to 0.80D1, which can also reduce the severe contraction, acceleration and vortex formation of the air flow at the inlet, significantly reducing the air intake vortex noise.

[0049] In addition, the upper limit of D2 is set to 0.80D1, which prevents the central hole of the wheel cover 31 from being too large, ensures that the wheel cover 31 has sufficient structural strength and rigidity to withstand the air flow force, centrifugal force and possible vibration during operation, improves the reliability and service life of the fan, and reduces the risk of additional noise caused by deformation or vibration of the wheel cover 31.

[0050] Preferably, as shown in Figure 2 The height of the heat exchanger 2 is H1, the vertical height between the outer side surface of the wheel cover 31 and the outer side surface of the fan wheel disc 32 is H2, and 0.67H1≤H2≤0.71H1.

[0051] The present application controls the height H2 of the fan blade 33 area between 0.67 to 0.71 times the height H1 of the heat exchanger 2, so that the distribution range of the airflow generated by the fan in the vertical direction is highly matched with the range covered by the heat exchanger 2, and the airflow can more evenly cover the vertical height of the entire heat exchanger 2, avoiding the occurrence of serious airflow low-speed area or dead zone at the upper and lower parts of the heat exchanger 2, and also avoiding a large amount of airflow impacting the structure outside the range of the heat exchanger 2, so that the wind speed distribution on the surface of the fins of the entire heat exchanger 2 is more uniform.

[0052] Uniform airflow coverage means that almost all the fin surface area of the heat exchanger 2 can effectively participate in heat exchange, fully utilizing the capacity of the heat exchanger 2, and the design of 0.67H1≤H2≤0.71H1 ensures that most of the airflow generated by the fan can effectively flow through the heat exchanger 2, thereby improving the heat exchange efficiency.

[0053] In addition, uniform airflow distribution and matched size relationship greatly reduce airflow separation, vortex and turbulence at the upper and lower edges of the heat exchanger 2, avoid impact noise generated by high-speed airflow directly impacting the structure outside the range of the heat exchanger 2, and significantly reduce the aerodynamic noise generated by the air conditioner indoor unit when it is running.

[0054] Preferably, as shown in Figure 2 and 4 The wheel cover 31 includes an annular base body 311 and a wind guide portion 312 arranged at the edge of the annular base body 311 in the circumferential direction of the annular base body 311, the annular base body 311 has an air inlet 35 in the middle, the wind guide portion 312 overlaps the blade 33 in the vertical direction, and along the radial direction of the annular base body 311, the connecting line of the two ends of the wind guide portion 312 forms a preset angle with the horizontal plane where the annular base body 311 is located, and the vertical height between the end of the wind guide portion 312 away from the annular base body 311 and the fan wheel disc 32 is the air outlet height H3 of the air outlet 34, and 0.71H2≤H3≤0.75H2.

[0055] The present application defines the vertical distance between the outermost end (the end away from the annular base body 311) of the wind guide portion 312 and the outer surface of the fan wheel disc 32 as the air outlet height H3 of the air outlet 34, that is, H3 is the axial height of the airflow actually and effectively flowing out of the fan impeller. 0.71H2≤H3≤0.75H2 ensures that the airflow can smoothly and efficiently transition into the outlet chamber between the heat exchanger 2 and the centrifugal fan 3, and maximally reduces the flow loss and noise generation of the airflow in the outlet chamber.

[0056] Exemplarily, the preset angle in the present application is 30°-40°.

[0057] The inclination angle in the angle range of 0°-40° provides the best curvature, enabling the high-speed radial airflow to change direction smoothly and gradually, significantly reducing airflow impact loss, flow separation loss and vortex dissipation, converting more fan input energy into useful wind pressure and wind volume, improving the aerodynamic efficiency of the fan, reducing airflow instability and possible backflow, and helping to maintain more stable wind volume output and more uniform air outlet.

[0058] In addition, the angle range of 30°-40° ensures that the airflow enters the outlet chamber in a more uniform and more designed direction, reducing the turbulent noise generated at the outlet chamber due to sudden speed changes, direction disorder and local vortex, and improving user comfort.

[0059] Preferably, as shown in Figures 3 to 5 The blade 33 includes a leading edge 331 for introducing external air between the plurality of blades 33 and a trailing edge 332 for discharging air between the plurality of blades 33. In adjacent two blades 33, the windward surface of one blade 33 has an outlet characteristic line 333 from top to bottom, which is formed by connecting the points on the windward surface of the blade 33 closest to the trailing edge 332 of the adjacent blade 33. The trailing edge 332 of the blade 33 corresponds to the position of the outlet characteristic line 333 of the adjacent blade 33, and the two form an air outlet 34 of the centrifugal fan 3, and the width of the air outlet 34 decreases first and then increases from top to bottom.

[0060] For example, for each blade 33, a "virtual line" is found on its pressure surface (windward surface), and each point on the line is the closest point from the point to the trailing edge 332 of the adjacent blade 33. Connecting this series of "closest points" gives the outlet characteristic line 333. Compared with the prior art, the air outlet 34 is no longer a simple "trailing edge 332-trailing edge 332" channel, but a three-dimensional slit formed by the trailing edge 332 and the outlet characteristic line 333.

[0061] During operation of the centrifugal fan 3, gas is sucked from the air inlet 35 and flows radially out after working on the blade 33. Due to the non-uniform distribution of the width of the air outlet 34 in the vertical direction (the height direction of the blade 33) (similar to an hourglass shape), the contraction section increases the airflow speed, reduces the displacement thickness of the boundary layer, and reduces the blockage; the expansion section avoids flow separation caused by excessive expansion. Therefore, under the same speed and power consumption, the effective flow area is increased and the wind volume is improved.

[0062] In addition, in traditional fans, the air outlet area of ​​each layer at the same blade height 33 is the same, but due to the influence of boundary layer and radial pressure gradient, the flow rate at the top and bottom is different, resulting in discrete noise. This design designs the width of the air outlet 34 from top to bottom as "first decrease and then increase", so that the outlet area at each axial position matches the actual flow rate, thereby "flattening" the flow peak and balancing the flow rate in each area, thus significantly reducing discrete frequency noise.

[0063] Preferably, such as Figure 5 As shown, in two adjacent blades 33, the trailing edge 332 of one blade 33 includes a first segment 3321 and a second segment 3322 distributed vertically. The first segment 3321 is inclined from top to bottom toward the windward side of the blade 33, and the second segment 3322 is inclined from top to bottom toward the leeward side of the blade 33. The outlet feature line 333 of the other blade 33 is curved into an arc from top to bottom toward the windward side. The first segment 3321 has a first feature point P1. The width of the air outlet 34 is the smallest at the first feature point P1, and the width of the top of the air outlet 34 is smaller than the width of the bottom of the air outlet 34.

[0064] Understandably, in two adjacent blades 33, the first segment 3321 of one blade 33 tilts downwards towards the windward side (the pressure side of the blade 33), while the second segment 3322 tilts downwards towards the leeward side (the suction side of the blade 33). Overall, the trailing edge 332 is shaped like an "S" or an inverted "S," resulting in different angles and distances between the trailing edge 332 and the exit feature line 333 at different axial heights. The exit feature line 333 on the other blade 33 is an arc curving downwards towards the windward side, which dynamically matches the segmented structure of the trailing edge 332 of the adjacent blade 33. This arc design coordinates the tilt angle of the exit feature line 333 with that of the first segment 3321, guiding the airflow along a specific path.

[0065] The first section 3321 is tilted towards the windward side, allowing the airflow to transition along a smoother path when leaving the blade 33, reducing airflow separation at the trailing edge 332; the second section 3322 is tilted towards the leeward side, forming an expansion channel that allows the airflow to fully diffuse after leaving the blade 33, suppressing the formation of wake vortices. This significantly reduces the intensity of the vortex at the trailing edge 332, thereby significantly reducing energy loss.

[0066] The arc-shaped structure of the outlet feature line 333 matches the inclination angle of the first segment 3321 of the trailing edge 332, forming a "contraction-expansion" flow channel structure. The airflow accelerates when passing through the narrowest point (P1), and then decelerates and increases pressure in the expansion section, conforming to the Venturi effect principle. This makes the pressure distribution at the outlet 34 more uniform, avoiding backflow caused by local high-pressure areas or airflow adsorption caused by low-pressure areas.

[0067] Furthermore, the width of the air outlet 34 is smallest at P1, forming a "throat" structure that accelerates airflow and enhances centrifugal projection capability; the narrower width at the top maintains high-speed airflow, while the wider width at the bottom allows more gas to be discharged, resulting in an overall increase in air volume. Compared to a traditional air outlet 34 with a uniform width, this design can significantly increase air volume.

[0068] Preferably, the first segment 3321 also has a second feature point P2, which is located above the first feature point P1. The second feature point P2 and the first feature point P1 divide the first segment 3321 into a first sub-segment, a second sub-segment, and a third sub-segment from top to bottom, and the inclination of the first sub-segment, the second sub-segment, and the third sub-segment increases sequentially.

[0069] This invention divides the first segment 3321 into three sub-segments with progressively increasing inclination, allowing the airflow to undergo a gradual process as it passes through each segment. This design conforms to the principle of "laminar acceleration" in fluid dynamics, preventing separation or vortices caused by sudden contraction or expansion of the airflow. This results in a smoother gradient of contraction and expansion from top to bottom at the outlet 34, avoiding uneven flow caused by excessively rapid contraction and expansion in local areas, thereby improving acceleration efficiency. Preferably, both the first segment 3321 and the second segment 3322 are Bézier curves or B-spline curves.

[0070] By using Bézier curves or B-spline curves for both the first segment 3321 and the second segment 3322, high-order continuity within the curve and between segments is ensured, providing an extremely smooth flow guiding surface, significantly improving flow stability, suppressing turbulence and separation, and effectively reducing high-frequency noise induced by geometric factors.

[0071] It should be noted that in other embodiments, the first segment 3321 and the second segment 3322 can also be straight segments. The present invention does not limit the specific shape of the first segment 3321 and the second segment 3322, as long as it can satisfy the requirements of reducing the noise of the centrifugal fan 3 during operation and improving the uniformity of the air volume and air flow.

[0072] Preferably, such as Figure 3 As shown, from the top of the leading edge 331 to the bottom of the leading edge 331, the leading edge 331 is an arc with a gradually increasing tangential slope, and the leading edge 331 is tilted towards the leeward side of the blade 33.

[0073] From the top end to the bottom end of the leading edge 331, the leading edge 331 is arc-shaped with gradually increasing tangent slope, in this embodiment, it means that from the top end close to the wheel cover 31 to the bottom end close to the fan wheel disc 32 along the height direction of the blade 33, the tangent slope of the leading edge 331 gradually increases, that is, at the position close to the wheel cover 31 (top end), the leading edge 331 is relatively flat, at the position close to the fan wheel disc 32 (bottom end), the leading edge 331 is relatively steep, and from the top end to the bottom end, the bending degree of the leading edge 331 is continuously and smoothly gradually steepened.

[0074] The present application matches the relative speed direction when the relative speed is low at the bottom end close to the fan wheel disc 32 by designing the leading edge 331 to be steeper, significantly reduces the attack angle of the airflow entering the flow passage of the blade 33, and makes it closer to the ideal small attack angle or zero attack angle state. Therefore, the airflow can flow more smoothly on the suction surface of the blade 33, eliminating separation vortex, so that the airflow can also effectively pass through the bottom area of the flow passage, the effective flow area is increased and the flow loss is reduced, the volumetric efficiency of the fan is improved, thereby effectively eliminating the noise during air intake, and significantly increasing the air intake and exhaust flow.

[0075] At the top end close to the wheel cover 31, the leading edge 331 is designed to be relatively flat (small tangent slope). This is more suitable for the relative speed direction when the relative speed is high at this position. Therefore, the airflow impact and possible micro-separation at the blade tip area are reduced, the gentle top end leading edge 331 helps the airflow to enter smoothly, avoids the noise caused by the sudden impact of air on the blade 33, and makes the air intake along the entire height direction of the blade 33 (from the wheel cover 31 to the fan wheel disc 32) more reasonable and uniform.

[0076] The present application can significantly reduce the attack angle of the airflow impacting the leading edge 331 of the blade 33 by tilting the leading edge 331 towards the leeward side, so that the airflow flows more smoothly and closely into the flow passage between the blades 33, so that the air has a more suitable direction and speed when entering the blade 33 area, further optimizing the air introduction process, and helping to improve the air pumping capacity of the fan.

[0077] In addition, the tilting of the leading edge 331 towards the leeward side makes the air entering the blade 33 area from the outside have a more stable transition. The air will not be suddenly blocked by the leading edge 331 of the blade 33 to produce strong impact and pressure change, and this stable transition reduces the noise caused by the sudden change of pressure, making the fan run more quietly.

[0078] In addition, the present application provides an embedded air conditioner, which comprises an outdoor unit and the embedded air conditioner indoor unit described above, and the outdoor unit is connected with the embedded air conditioner indoor unit.

[0079] The technical scheme of the present application has been described in combination with the preferred embodiments shown in the drawings, but it is easy for those skilled in the art to understand that the protection scope of the present application is obviously not limited to these specific embodiments. Those skilled in the art can make equivalent changes or replacements to the related technical features without departing from the principles of the present application, and the technical schemes after the changes or replacements will all fall within the protection scope of the present application.

Claims

1. An embedded air conditioner indoor unit, characterized in that, The device includes a housing (1) and a heat exchanger (2) and a centrifugal fan (3) located inside the housing (1) and vertically mounted on the bottom plate of the housing (1). The heat exchanger (2) surrounds the centrifugal fan (3) circumferentially, and the heat exchanger (2) is arranged opposite to the air outlet (34) of the centrifugal fan (3). The heat exchanger (2) forms a minimum distance L1 with the air outlet (34) at least at one point, where 0.74L1≤D1≤0.78L1, and D1 is the diameter of the centrifugal fan (3).

2. The embedded air conditioner indoor unit according to claim 1, characterized in that, The heat exchanger (2) is rectangular in shape, and the dimensions of the heat exchanger (2) along the first direction and the second direction are L2 and L3 respectively, and L2≥L3, 0.74L3≤D1≤0.78L3, and the first direction is perpendicular to the second direction.

3. The embedded air conditioner indoor unit according to claim 1, characterized in that, The centrifugal fan (3) includes a wheel cover (31) and a fan disc (32) arranged opposite each other in the vertical direction. Multiple blades (33) are spaced apart between the wheel cover (31) and the fan disc (32). The multiple blades (33) are distributed circumferentially along the fan disc (32). An air inlet (35) is provided on the wheel cover (31). The diameter of the air inlet (35) is D2, where 0.78D1≤D2≤0.8D1.

4. The embedded air conditioner indoor unit according to claim 3, characterized in that, The height of the heat exchanger (2) is H1, and the vertical distance between the outer surface of the wheel cover (31) and the outer surface of the fan wheel (32) is H2, where 0.67H1≤H2≤0.71H1.

5. The embedded air conditioner indoor unit according to claim 4, characterized in that, The wheel cover (31) includes an annular base (311) and a guide section (312) arranged circumferentially around the edge of the annular base (311). The annular base (311) has an air inlet (35) in the middle. The guide section (312) overlaps with the blade (33) in the vertical direction. Along the radial direction of the annular base (311), the line connecting the two ends of the guide section (312) forms a preset angle with the horizontal plane where the annular base (311) is located. The vertical height between the end of the guide section (312) away from the annular base (311) and the fan wheel (32) is the air outlet height H3 of the air outlet (34), where 0.71H2≤H3≤0.75H2.

6. The embedded air conditioner indoor unit according to claim 3, characterized in that, The blade (33) includes a leading edge (331) and a trailing edge (332), the leading edge (331) being used to introduce outside air between the plurality of blades (33). In two adjacent blades (33), one of the blades (33) has an outlet feature line (333) from top to bottom on its windward surface. The outlet feature line (333) is formed by connecting the points on the windward surface of the blade (33) that are closest to the trailing edge (332) of the adjacent blade (33). The trailing edge (332) of the blade (33) corresponds to the outlet feature line (333) of the adjacent blade (33), and the two form the air outlet (34) of the centrifugal fan (3). The width of the air outlet (34) decreases first and then increases from top to bottom.

7. The embedded air conditioner indoor unit according to claim 6, characterized in that, In two adjacent blades (33), the trailing edge (332) of one blade (33) includes a first segment (3321) and a second segment (3322) distributed vertically. The first segment (3321) is inclined from top to bottom toward the windward side of the blade (33), and the second segment (3322) is inclined from top to bottom toward the leeward side of the blade (33). The outlet feature line (333) of the other blade (33) is curved into an arc from top to bottom toward the windward side. The first segment (3321) has a first feature point P1. The width of the air outlet (34) is the smallest at the first feature point P1, and the width of the top of the air outlet (34) is smaller than the width of the bottom of the air outlet (34).

8. The embedded air conditioner indoor unit according to claim 7, characterized in that, The first segment (3321) also has a second feature point P2, which is located above the first feature point P1. The second feature point P2 and the first feature point P1 divide the first segment (3321) into a first sub-segment, a second sub-segment and a third sub-segment from top to bottom, and the inclination of the first sub-segment, the second sub-segment and the third sub-segment increases sequentially.

9. The embedded air conditioner indoor unit according to claim 6, characterized in that, From the top end to the bottom end of the leading edge (331), the leading edge (331) forms an arc with a gradually increasing tangent slope, and / or The leading edge (331) is inclined toward the leeward side of the blade (33).

10. An embedded air conditioner, characterized in that, It includes an outdoor unit and an embedded air conditioning indoor unit as described in any one of claims 1 to 9, wherein the outdoor unit is connected to the embedded air conditioning indoor unit.

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