Range hood and design method thereof

Abstract

The present invention discloses a range hood and a design method thereof. The range hood includes a smoke collecting chamber and a fan assembly disposed above the smoke collecting chamber. The smoke collecting chamber is connected to the fan assembly. The fan assembly includes a fan frame and a centrifugal fan disposed on the fan frame. The centrifugal fan is obliquely disposed in the fan frame along the height direction of the range hood. A guide area is formed between the centrifugal fan and a rear cover plate of the fan frame corresponding to the outlet direction of the smoke collecting chamber, and the inlet of the centrifugal fan is disposed toward the guide area. By obliquely disposing the centrifugal fan in the fan frame and forming the guide area corresponding to the outlet direction of the smoke collecting chamber, compared to a method in which the centrifugal fan is parallel to the smoke collecting chamber, the angle between the axis of the centrifugal fan and the smoke collecting chamber is correspondingly reduced, the resistance of oil smoke entering the centrifugal fan from the outlet of the smoke collecting chamber is reduced, the flow loss inside the range hood is reduced, the work efficiency of the centrifugal fan is improved, and the noise is reduced.

Description

Technical Field

[0001] The present invention particularly relates to a range hood and a design method thereof. Background Art

[0002] As a kitchen appliance, the range hood is mainly used to exhaust the oil smoke generated during cooking to the outside. Existing range hoods can be divided into low-suction, side-suction and top-suction types according to the position of the air inlet. With the improvement of living standards, people have higher requirements for the performance, appearance and noise of range hoods. For low-suction range hoods, especially those with ultra-thin smoke collection chambers, in order to free up the operating space above the stove, the thickness of the smoke collection chamber is usually set to be smaller, so that the range hood can free up the operating space above the stove and the air inlet is located relatively close to the stove. Such range hoods can "capture" the oil smoke into the air intake channel at the early stage of diffusion and have better smoke collection capabilities. Therefore, they have been favored by users in recent years.

[0003] For range hoods with top-mounted fans (the fan is located above the smoke collection chamber), in order to balance noise performance at both times (at the store and when used by users), larger dual-inlet multi-blade centrifugal fans are generally placed vertically in the fan frame. The smoke collection chamber of low-suction, ultra-thin range hoods is designed to have a narrow channel, causing the airflow in the chamber to flow vertically upward under the drive of the negative pressure of the top-mounted fan. Compared with range hoods with other smoke collection chamber types, the flow rate is relatively large and has a certain degree of directionality. When the airflow reaches the fan inlet and impeller inlet, it turns, making it more likely to produce flow separation and vortexes, affecting the performance and noise of the range hood. In addition, the narrow design of the smoke collection chamber increases the resistance at the front end of the centrifugal fan's inlet, which can easily cause flow losses at the centrifugal fan inlet under high flow conditions. In other words, the flow entering the centrifugal fan is insufficient, which in turn affects the smoke exhaust effect of the entire machine and increases operating noise, preventing the centrifugal fan from fully exerting its performance and affecting the user experience.

[0004] To address the above issues, the prior art generally improves the lower box structure (or smoke collecting chamber) solution. Although the resistance of the smoke collecting chamber is improved to a certain extent, it does not deviate from the design of the ultra-thin lower box, and the structure is complex, which increases the design cost. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a range hood and a design method thereof in order to overcome the defect in the prior art that the smoke collecting chamber is narrow and the inlet front end resistance of the centrifugal fan is obvious.

[0006] The present invention solves the above technical problems through the following technical solutions:

[0007] A range hood, comprising a smoke collecting chamber and a fan assembly disposed above the smoke collecting chamber, the smoke collecting chamber being in communication with the fan assembly, the fan assembly comprising a fan frame and a centrifugal fan disposed on the fan frame, the centrifugal fan being obliquely disposed in the fan frame along the height direction of the range hood, a guide area being formed between the centrifugal fan and a rear cover of the fan frame corresponding to the outlet direction of the smoke collecting chamber, and an inlet of the centrifugal fan being disposed toward the guide area; an angle θ formed between the centrifugal fan and the rear cover of the fan frame is calculated according to formula (1), which is: Wherein, L is the thickness of the fan frame, H is the height of the fan frame, B is the thickness of the volute of the centrifugal fan, and K is the height of the volute of the centrifugal fan.

[0008] In this solution, by tilting the centrifugal fan in the fan frame and forming a guide area in the direction of the smoke collection chamber outlet corresponding to the back plate of the fan frame, the angle between the axis of the centrifugal fan and the smoke collection chamber is reduced accordingly compared to the method in which the centrifugal fan is arranged along the height direction of the range hood and parallel to the smoke collection chamber, and the resistance of the oil smoke entering the centrifugal fan from the smoke collection chamber outlet is reduced, thereby reducing the internal flow loss of the range hood in the range hood with a relatively narrow smoke collection chamber, improving the work efficiency of the centrifugal fan, and improving the aerodynamic performance of the oil smoke extraction. In addition, the tilted centrifugal fan also makes the oil smoke turn less when it passes through the centrifugal fan inlet, reducing flow separation and vortex, and thus reducing the noise of the range hood under the same working conditions and air volume. The above formula is used to calculate the tilt angle of the centrifugal fan based on the size of the fan frame and the volute.

[0009] Preferably, the outlet of the volute has a first plane and a second plane arranged opposite to each other, the first plane is arranged in parallel with the second plane, and the first plane and the second plane are inclined toward the side of the volute away from the inlet of the centrifugal fan.

[0010] In this solution, the aforementioned arrangement of the inclined first and second planes at the volute outlet improves the centrifugal fan's intake airflow, which is relatively concentrated in the outlet area of ​​the volute rotating surface, compared to a case where the volute outlet and the volute surface are arranged flush with each other. This prevents the volute outlet airflow from shifting toward the side of the volute away from the inlet due to the tilted placement of the centrifugal fan, avoids an increase in the airflow velocity gradient in the volute outlet area, reduces turbulent motion, and improves the performance of the centrifugal fan.

[0011] Preferably, the volute includes an upper cover plate, a lower cover plate and an annular wall located between the upper cover plate and the lower cover plate, the first plane is inclined to the upper cover plate through a bending line, the second plane is inclined to the lower cover plate through a bending line, the bending line includes a first end point and a second end point, wherein the first end point is located at the outlet of the volute and close to the volute tongue of the volute, and the second end point is located at the outlet section on the volute profile line.

[0012] In this solution, by connecting the outlet areas of the upper and lower cover plates of the volute to the first and second planes via a bending line, and by tilting the first plane relative to the upper cover plate and the second plane relative to the lower cover plate, the volute outlet airflow shifts toward the volute lower cover plate when the centrifugal fan is tilted. This prevents an increase in the airflow velocity gradient in the volute outlet area, reduces turbulent motion, and improves the performance of the centrifugal fan. In addition, the outlet section with the second endpoint located on the volute profile ensures the area of ​​the first and second planes, improving the airflow at the volute outlet.

[0013] Preferably, a coordinate system is formed from the impeller axis of the volute along the height direction of the volute and perpendicular to the height direction of the volute, wherein the axis extending along the height direction of the volute toward the outlet of the volute is the positive direction of the Y axis, the axis extending perpendicular to the height direction of the volute and away from the outlet of the volute is the positive direction of the X axis, and the angle between the second endpoint and the positive direction of the X axis of the coordinate system is greater than 180°.

[0014] In this solution, through the above arrangement, compared with the case where the angle between the second endpoint and the positive direction of the X-axis of the coordinate system is less than 180°, the second endpoint is further away from the volute tongue, so that the areas of the first plane and the second plane are guaranteed.

[0015] Preferably, the range hood further comprises an air outlet hood, which is arranged at the outlet of the volute; and / or the air outlet hood comprises a bent section, which is located between the two ends of the air outlet hood.

[0016] In this solution, an air outlet hood is provided to guide the airflow at the volute outlet, that is, the oil smoke sucked from the smoke collection chamber by the range hood, and discharge it into the flue to prevent the oil smoke from escaping. In order to better guide the airflow at the volute outlet, a bent section, i.e., a curved structure, is provided between the two ends of the air outlet hood.

[0017] Preferably, the end of the air outlet hood connected to the outlet of the volute is arranged perpendicular to the plane where the outlet of the volute is located; and / or the end of the air outlet hood away from the outlet of the volute is arranged perpendicular to the plane where the air outlet of the range hood is located.

[0018] In this solution, the above-mentioned configuration is used to reduce the airflow loss at the volute outlet. The centrifugal fan is tilted in the range hood to improve the airflow state of the range hood, thereby enhancing the aerodynamic performance of the entire range hood.

[0019] A range hood design method, the design method being applied to the range hood as described above, is characterized in that the range hood design method comprises the following steps:

[0020] S1. Through geometric parameter modeling, the finite element analysis software is used to simulate the flow field in the range hood to obtain the effect of α, β, and θ on the total pressure P of the whole machine. t and the total pressure efficiency η, where P t is the sum of the static pressure and dynamic pressure at the outlet of the centrifugal fan, η is the output power / input power of the centrifugal fan, α is the angle between the second end point of the volute of the centrifugal fan and the positive direction of the X-axis of the coordinate system, β is the angle between the first plane of the volute facing the upper cover plate and the upper cover plate, and / or between the second plane of the volute facing the lower cover plate and the lower cover plate, and θ is the angle between the centrifugal fan and the rear cover plate of the fan frame;

[0021] S2. Determine the optimal range of α, β, and θ based on single factor analysis.

[0022] In this scheme, by analyzing α, β, θ, the total pressure P of the whole machine is t The influence relationship between α, β and θ is determined based on the single factor analysis, which is convenient for designers to optimize and determine the value range of α, β and θ.

[0023] Preferably, step S2 specifically includes:

[0024] Based on the above influence relationship, the Box-Beknken experimental design is used to obtain the influence of α, β and θ on the total pressure P of the whole machine. t The three-variable linear regression equation of total pressure efficiency η is:

[0025] P t =81.36+0.5475α-0.5925β+1.37θ;

[0026] η=33.02-0.0984α+0.027β+0.5689θ.

[0027] In this scheme, the optimization ranges of α, β and θ are determined based on single factor analysis, and the Box-Beknken experimental design is used to obtain the effects of α, β and θ on the total pressure P of the whole machine. t Ternary linear regression equation of total pressure efficiency η and optimal parameter combination scheme.

[0028] Preferably, when calculating the ternary linear regression equation, a large sample size approach is used for optimization.

[0029] In this scheme, the method of looking for a large sample target is adopted to obtain a more beneficial value and obtain the optimized total pressure P t and the total pressure efficiency η are improved compared with the prototype, which enhances the optimization effect.

[0030] The positive progress of the present invention lies in that: by arranging the centrifugal fan at an angle within the fan frame and forming a guide area with the back plate of the fan frame in the direction of the smoke collection chamber outlet, the angle between the axis of the centrifugal fan and the smoke collection chamber is correspondingly reduced compared to the method of arranging the centrifugal fan along the height direction of the range hood and parallel to the smoke collection chamber, thereby reducing the resistance of oil smoke entering the centrifugal fan from the smoke collection chamber outlet. In addition, in range hoods with relatively narrow smoke collection chambers, the internal flow loss of the range hood is reduced, the work efficiency of the centrifugal fan is improved, and the aerodynamic performance of the oil smoke extraction is enhanced. In addition, the inclined centrifugal fan also makes the oil smoke turn less when it enters the centrifugal fan inlet, reducing flow separation and vortex, thereby reducing the noise of the range hood under the same working conditions and air volume. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 FIG1 is a perspective view of a range hood according to a preferred embodiment of the present invention.

[0032] Figure 2 This is a three-dimensional diagram of a volute according to a preferred embodiment of the present invention.

[0033] Figure 3 It is a front view of a volute according to a preferred embodiment of the present invention.

[0034] Figure 4 FIG. 1 is a top view of a volute according to a preferred embodiment of the present invention.

[0035] Figure 5 This is a three-dimensional diagram of a fan assembly according to a preferred embodiment of the present invention.

[0036] Figure 6 This is a front view of a fan assembly according to a preferred embodiment of the present invention.

[0037] Figure 7 This is a side view of a fan assembly according to a preferred embodiment of the present invention.

[0038] Description of reference numerals:

[0039] Range hood 100

[0040] Smoke chamber 10

[0041] Fan assembly 20

[0042] Wind rack 21

[0043] rear cover 211

[0044] Front cover 212

[0045] Top plate 213

[0046] Base plate 214

[0047] Centrifugal fan 22

[0048] Volute 221

[0049] Upper cover 2211

[0050] Lower cover 2212

[0051] Ring wall 2213

[0052] Snail tongue 2214

[0053] Diversion area 1

[0054] First plane 2

[0055] Second plane 3

[0056] Bending line 4

[0057] First endpoint 41

[0058] Second endpoint 42

[0059] Air outlet hood 5

[0060] Bending section 51 DETAILED DESCRIPTION

[0061] The present invention is further described below by way of examples, but the present invention is not limited to the scope of the examples.

[0062] This embodiment provides a range hood 100, the specific structure of which is as follows Figure 1 、 Figure 2 、 Figure 3 、 Figure 4 、 Figure 5 、 Figure 6 and Figure 7 As shown, the range hood 100 includes a smoke collecting chamber 10 and a fan assembly 20 arranged above the smoke collecting chamber 10. The smoke collecting chamber 10 is connected to the fan assembly 20. The fan assembly 20 includes a fan frame 21 and a centrifugal fan 22 arranged on the fan frame 21. The centrifugal fan 22 is arranged in the fan frame 21 at an angle along the height direction of the range hood 100. A guide area 1 is formed between the centrifugal fan 22 and the rear cover plate 211 of the fan frame 21 corresponding to the outlet direction of the smoke collecting chamber 10, and the inlet of the centrifugal fan 22 is arranged toward the guide area 1.

[0063] Specifically, the smoke collection chamber 10 is arranged below the fan assembly 20 along the height direction of the range hood 100. The thickness of the smoke collection chamber 10 is less than that of the fan assembly 20 and extends toward the stove, so as to be close to the stove while reducing the space occupied in the projection direction of the stove, so that the oil smoke generated by the stove cooking can be quickly introduced into the range hood 100 through the smoke collection chamber 10 in the early stage of generation. This is a prior art and will not be described in detail here. In this embodiment, the smoke collection chamber 10 and the side wall of the fan assembly 20 on the side close to the wall are arranged flush, and the side wall of the fan assembly 20 on the side close to the wall is the rear cover 211 of the fan frame 21. The fan frame 21 is a rectangular parallelepiped structure and the centrifugal fan 22 is tilted in the fan frame 21. The inlet of the centrifugal fan 22 is located at the axis of the centrifugal fan 22 and faces the rear cover 211. It is arranged at an angle to the rear cover 211, so that the centrifugal fan 22 is tilted relative to the rear cover 211 to form a guide area 1 in the fan frame 21. The diversion area 1 is a triangular area when viewed from the side. The diversion area 1 corresponds to the outlet direction of the smoke collecting chamber 10. Due to the shrinkage of the flow area of ​​the smoke collecting chamber 10, the flow velocity here is relatively high. The inclined centrifugal fan 22 reduces the turning angle of the oil smoke flowing from the smoke collecting chamber 10 into the fan assembly 20 when entering the inlet of the centrifugal fan 22. Compared with the method in which the centrifugal fan 22 is arranged along the height direction of the range hood 100 and parallel to the smoke collecting chamber 10, the angle between the axis of the centrifugal fan 22 and the smoke collecting chamber 10 is correspondingly reduced from the vertical arrangement. The resistance of the oil smoke entering the centrifugal fan 22 from the outlet of the smoke collecting chamber 10 is reduced, thereby reducing the internal flow loss of the range hood 100 in the relatively narrow smoke collecting chamber 10, improving the work efficiency of the centrifugal fan 22, giving full play to the performance of the centrifugal fan 22, and improving the aerodynamic performance of the oil smoke extraction.

[0064] In addition, in this embodiment, the inclined centrifugal fan 22 also makes the oil smoke turn less when entering the centrifugal fan 22, reducing the separation and vortex of the air flow in the fan frame 21, thereby reducing the noise of the range hood 100 under the same working conditions and air volume, and realizing the noise reduction function of the range hood 100.

[0065] It can be understood that in this embodiment, both the oil smoke and the airflow are gases, which represent that the range hood 100 is in different working conditions, namely, inside the store and in the kitchen. This embodiment places the centrifugal fan 22 at an angle to improve the aerodynamic performance and noise reduction effect of the range hood 100 under different working conditions.

[0066] In this embodiment, the angle θ between the centrifugal fan 22 and the rear cover 211 of the fan frame 21 is calculated according to formula (1), which is: Wherein, L is the thickness of the fan frame, H is the height of the fan frame, B is the thickness of the volute of the centrifugal fan, and K is the height of the volute of the centrifugal fan.

[0067] Specifically, if Figure 3 、 Figure 4 and Figure 7 As shown, the centrifugal fan 22 includes a volute 221, which includes an upper cover plate 2211, a lower cover plate 2212 and an annular wall 2213 located between the upper cover plate 2211 and the lower cover plate 2212. The volute 221 has an inlet and an outlet, wherein the outlet section of the volute 221 is located on the side of the volute 221, and the inlet of the volute 221 is located at the axis of the volute 221. The fan frame 21 includes a front cover plate 212 corresponding to the rear cover plate 211, as well as a top plate 213 and a bottom plate 214 of the fan frame 21. The volute 221 is located in a space enclosed by the front cover plate 212, the rear cover plate 211, the top plate 213, the bottom plate 214 and the side plates. It should be noted that the centrifugal fan 22 includes components such as the volute 221, an impeller (not shown in the figure) and a collector (not shown in the figure), and the inlet of the volute 221 is the inlet of the centrifugal fan 22. That is to say, when the centrifugal fan 22 is tilted in the fan frame 21, the volute 221 is also tilted in the fan frame 21.

[0068] The angle θ between the centrifugal fan 22 and the rear cover 211 of the fan frame 21 is calculated by formula (1), that is, the angle θ between the volute 221 and the rear cover 211 of the fan frame 21 is calculated. By substituting the actual size of the fan frame 21 and the actual size of the volute 221 of the centrifugal fan 22 into the formula In order to calculate the value of the angle θ, in this embodiment, L=316mm, H=420mm, B=190mm, and K=390mm are used as an example for explanation, but the range of values ​​is not limited. Calculation shows that θ≤21.99°.

[0069] In other embodiments, the value can be determined based on the actual size of the fan rack 21, which will not be elaborated on here. It should be noted that through simulation and experimental research using simulation software in the prior art, it can be seen that when θ is small, the range hood 100 with an ultra-thin smoke collection chamber 10 structure does not significantly reduce the resistance at the inlet of the centrifugal fan 22, and does not achieve the purpose of performance improvement or noise reduction. In addition, since the outlet of this type of range hood 100 is generally vertically upward, when θ is large, the flow loss of the airflow turning at the outlet of the centrifugal fan 22 will increase, affecting the performance improvement and noise reduction effect of the entire machine. Therefore, in the case of changes in the values ​​of L, H, B and K in other fan racks 21, the value range of θ is usually above 4° and below 30°, that is, 4°≤θ≤30°.

[0070] Furthermore, in this embodiment, the outlet of the volute 221 has a first plane 2 and a second plane 3 that are relatively arranged, the first plane 2 and the second plane 3 are arranged in parallel, and the first plane 2 and the second plane 3 are inclined toward the inlet side of the volute 221 away from the centrifugal fan 22.

[0071] Specifically, the upper cover plate 2211 and the lower cover plate 2212 of the volute 221 are arranged in parallel and form an angle θ with the rear cover plate 211 of the fan frame 21, while the first plane 2 and the upper cover plate 2211, and the second plane 3 and the lower cover plate 2212 are arranged at an angle and are arranged toward the side of the volute 221 away from the inlet. Compared with the case where the outlet of the volute 221 is arranged as a flush plane with the upper cover plate 2211 and the lower cover plate 2212 of the volute 221, the situation in which the intake airflow of the centrifugal fan 22 is relatively concentrated in the outlet area of ​​the rotating surface of the volute 221 is improved. This prevents the outlet airflow of the volute 221 from moving toward the side of the volute 221 away from the inlet due to the tilt of the centrifugal fan 22, avoids the increase of the airflow velocity gradient in the outlet area of ​​the volute 221, reduces turbulent motion, and improves the performance of the centrifugal fan 22.

[0072] It should be noted that the intake air flow of the centrifugal fan 22 is relatively concentrated in the outlet area of ​​the rotating surface of the volute 221, and the meridian surface is close to the lower cover plate 2212 area. The impeller outlet air flow in the volute 221 moves toward the lower cover plate 2212 of the volute 221, which increases the velocity gradient in the outlet area of ​​the volute 221 and intensifies the turbulent motion. It can be seen from the simulation and experimental research using simulation software in the existing technology that this is the existing technology and will not be elaborated on here.

[0073] In this embodiment, the first plane 2 is inclined with the upper cover plate 2211 through the bending line 4, and the second plane 3 is inclined with the lower cover plate 2212 through the bending line 4. The bending line 4 includes a first endpoint 41 and a second endpoint 42, wherein the first endpoint 41 is located at the outlet of the volute 221 and is close to the volute tongue 2214 of the volute 221, and the second endpoint 42 is located at the outlet section on the volute 221 profile line.

[0074] Specifically, a volute tongue 2214 is provided near the outlet of the volute 221. The volute tongue 2214 is formed by enclosing the first plane 2, the second plane 3, and the annular wall 2213. The first plane 2 and the second plane 3 are integrally formed with the upper cover plate 2211 and the lower cover plate 2212 via a bending line 4. From the appearance, the area where the first plane 2 and the second plane 3 are located is inclined relative to the main body of the volute 221 and is inclined toward the side away from the inlet of the centrifugal fan 22, so as to form a bending structure on the volute 221. The bending structure improves the situation where the airflow at the outlet of the volute 221 moves toward the lower cover plate 2212 of the volute 221 when the centrifugal fan 22 is tilted, thereby preventing the airflow velocity gradient in the outlet area of ​​the volute 221 from increasing, reducing turbulent motion, and improving the performance of the centrifugal fan 22. This prevents the aerodynamic performance of the centrifugal fan 22 from being offset by the loss at the outlet of the volute 221 when the centrifugal fan 22 is tilted.

[0075] It can be understood that in order to ensure the drainage effect on the airflow at the outlet of the volute 221, by locating the second endpoint 42 at the outlet section on the volute 221 profile line, the bending line 4 formed by the line connecting the first endpoint 41 and the second endpoint 42 can ensure the area of ​​the first plane 2 and the second plane 3, thereby improving the airflow condition at the outlet of the volute.

[0076] In this embodiment, a coordinate system is formed from the impeller axis of the volute 221 along the height direction of the volute 221 and perpendicular to the height direction of the volute 221, wherein the axis extending along the height direction of the volute 221 toward the outlet of the volute 221 is the positive direction of the Y axis, and the axis extending perpendicular to the height direction of the volute 221 and away from the outlet of the volute 221 is the positive direction of the X axis, and the angle between the second endpoint 42 and the positive direction of the X axis of the coordinate system is greater than 180°.

[0077] Specifically, the origin of the coordinate system is the axis of the impeller, the positive direction of the Y-axis of the coordinate system is the axis extending along the height direction of the volute 221 toward the outlet of the volute 221, the negative direction of the Y-axis of the coordinate system is the axis extending along the height direction of the volute 221 away from the outlet of the volute 221, the positive direction of the X-axis of the coordinate system is perpendicular to the height direction of the volute 221 and away from the outlet of the volute 221, and the negative direction of the X-axis of the coordinate system is perpendicular to the height direction of the volute 221 and toward the outlet of the volute 221. It can be understood that the negative direction of the X-axis and the positive direction of the Y-axis are close to the outlet of the volute 221, and the second endpoint 42 is arranged at the outlet section on the volute 221 profile and forms an angle greater than 180° with the positive direction of the X-axis. Compared with the angle less than 180° between the second endpoint 42 and the positive direction of the X-axis of the coordinate system, the second endpoint 42 is farther away from the volute tongue 2214, so that the areas of the first plane 2 and the second plane 3 are guaranteed.

[0078] It can be understood that the establishment of the coordinate system is achieved through simulation software in the prior art, and its purpose is to determine the angle between the second endpoint 42 and the line connecting the impeller axis and the positive direction of the X-axis, and then determine the position of the second endpoint 42, and ensure the area of ​​the first plane 2 and the second plane 3. On this basis, when the centrifugal fan 22 is tilted, the airflow at the outlet of the volute 221 moves toward the side of the lower cover plate 2212 of the volute 221, thereby avoiding an increase in the airflow velocity gradient in the outlet area of ​​the volute 221, reducing turbulent motion, and improving the performance of the centrifugal fan 22.

[0079] Furthermore, the second endpoint 42 forms an angle α with the positive direction of the X-axis of the coordinate system, the first plane 2 forms an angle β with the side of the upper cover plate 2211 and the side of the second plane 3 forms an angle β with the side of the lower cover plate 2212.

[0080] This embodiment also provides a range hood design method, which is used for the range hood described above. The range hood design method includes the following steps:

[0081] S1. Through geometric parameter modeling, the finite element analysis software is used to simulate the flow field in the range hood and obtain the effect of α, β, and θ on the total pressure P of the whole machine. t and the total pressure efficiency η, where P t is the sum of the static pressure and dynamic pressure at the outlet of the centrifugal fan, η is the output power / input power of the centrifugal fan, α is the angle between the second end point of the volute of the centrifugal fan and the positive direction of the X-axis of the coordinate system, β is the angle between the first plane of the volute facing the upper cover plate and the upper cover plate, and / or between the second plane of the volute facing the lower cover plate and the lower cover plate, and θ is the angle between the centrifugal fan and the rear cover plate of the fan frame;

[0082] S2. Determine the optimal range of α, β, and θ based on the single factor analysis. The obtained parameter optimization range is used as the parameter range for response surface optimization, as shown in Table 1:

[0083] Table 1 Optimization range of structural parameters

[0084]

[0085] The Box-Behnken method was used for experimental design, and the experimental data are shown in Table 2:

[0086] Table 2 Test results

[0087]

[0088]

[0089] According to the sample data in Table 1 and Table 2, linear equation fitting is used to obtain the effects of α, β and θ on the total pressure P of the whole machine. t And the three-variable linear regression equation of total pressure efficiency η:

[0090] P t =81.36+0.5475α-0.5925β+1.37θ;

[0091] η=33.02-0.0984α+0.027β+0.5689θ.

[0092] The regression equation was solved by using a large sample method to obtain the optimal combination of structural parameters: α = 196°, β = 10°, θ = 22°.

[0093] It can be understood that, in this embodiment, the design parameters of the first plane 2 and the second plane 3 are the same, that is, the angle β is the same.

[0094] In this embodiment, the range hood 100 further includes an air outlet hood 5 , which is disposed at the outlet of the volute 221 .

[0095] Specifically, the inlet of the air outlet hood 5 is connected to the outlet of the volute 221, and the outlet of the air outlet hood 5 extends to the top of the range hood 100 and extends out of the fan assembly 20. By setting the air outlet hood 5, the airflow at the outlet of the volute 221, that is, the oil smoke sucked into the smoke collecting chamber 10 by the range hood 100, is guided and discharged into the flue to prevent the oil smoke from escaping.

[0096] Furthermore, the air outlet cover 5 includes a bending section 51 , and the bending section 51 is located between two ends of the air outlet cover 5 .

[0097] Specifically, the outlet of the volute 221 is formed by the first plane 2, the second plane 3 and the annular wall 2213. The outlet of the volute 221 is formed with four edges, and the air outlet hood 5 is provided with four curves corresponding to the four edges. The four curves are respectively located at the four corners of the air outlet hood 5 to form a bending section 51, that is, a curved structure, and then the airflow at the outlet of the volute 221 is discharged to avoid affecting the aerodynamic performance of the outlet of the volute 221.

[0098] In this embodiment, the end of the air hood 5 connected to the outlet of the volute 221 is arranged perpendicular to the plane of the outlet of the volute 221. By providing the bent section 51, the inlet end of the air hood 5 is arranged perpendicular to the plane of the outlet of the volute 221, thereby reducing the air flow loss at the outlet of the volute 221.

[0099] In this embodiment, the end of the air hood 5 away from the outlet of the volute 221 is arranged perpendicular to the plane of the air outlet of the range hood 100. It is understood that the plane of the air outlet of the range hood 100 is horizontal, while the end of the air hood 5 away from the outlet of the volute 221 is arranged perpendicular to the horizontal direction. In other words, the end of the air hood 5 away from the outlet of the volute 221 is arranged in the vertical direction. This achieves the purpose of adjusting the air outlet state of the range hood 100 while improving the aerodynamic performance and noise of the range hood 100 by tilting the centrifugal fan 22 in the range hood 100, facilitating air flow into the flue, and preventing the escape of oil smoke that may occur when the air outlet of the range hood 100 is tilted relative to the vertical direction.

[0100] Although specific embodiments of the present invention have been described above, those skilled in the art will appreciate that these are merely illustrative and that the scope of the present invention is defined by the appended claims. Those skilled in the art may make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, and such changes and modifications are intended to fall within the scope of the present invention.

Claims

1. A range hood comprising a smoke collecting chamber and a fan assembly disposed above the smoke collecting chamber, wherein the smoke collecting chamber is in communication with the fan assembly, the fan assembly comprising a fan frame and a centrifugal fan disposed on the fan frame, characterized in that: The centrifugal fan is arranged in the fan frame at an angle along the height direction of the range hood, and a guide area is formed between the centrifugal fan and the rear cover of the fan frame corresponding to the outlet direction of the smoke collecting chamber, and the inlet of the centrifugal fan is arranged toward the guide area; the angle θ between the centrifugal fan and the rear cover of the fan frame is calculated according to formula (1), which is: Wherein, L is the thickness of the fan frame, H is the height of the fan frame, B is the thickness of the volute of the centrifugal fan, and K is the height of the volute of the centrifugal fan.

2. The range hood according to claim 1, wherein: The outlet of the volute has a first plane and a second plane that are arranged opposite to each other. The first plane is arranged in parallel with the second plane, and the first plane and the second plane are inclined toward the side of the volute away from the inlet of the centrifugal fan.

3. The range hood according to claim 2, wherein: The volute includes an upper cover plate, a lower cover plate and an annular wall located between the upper cover plate and the lower cover plate, the first plane is inclined to the upper cover plate via a bending line, the second plane is inclined to the lower cover plate via a bending line, the bending line includes a first end point and a second end point, wherein the first end point is located at the outlet of the volute and close to the volute tongue of the volute, and the second end point is located at the outlet section on the volute profile line.

4. The range hood according to claim 3, wherein: A coordinate system is formed from the impeller axis of the volute along the height direction of the volute and perpendicular to the height direction of the volute, wherein the axis extending along the height direction of the volute toward the outlet of the volute is the positive direction of the Y axis, the axis extending perpendicular to the height direction of the volute and away from the outlet of the volute is the positive direction of the X axis, and the angle between the second endpoint and the positive direction of the X axis of the coordinate system is greater than 180°.

5. The range hood according to claim 2, wherein: The range hood further comprises an air outlet hood, which is arranged at the outlet of the volute; and / or the air outlet hood comprises a bent section, which is located between two ends of the air outlet hood.

6. The range hood according to claim 5, wherein: The end of the air outlet hood connected to the outlet of the volute is arranged perpendicular to the plane where the outlet of the volute is located; and / or the end of the air outlet hood away from the outlet of the volute is arranged perpendicular to the plane where the air outlet of the range hood is located.

7. A range hood design method, the design method being applied to the range hood according to claim 4, characterized in that: The range hood design method comprises the following steps: S1. Through geometric parameter modeling, the finite element analysis software is used to simulate the flow field in the range hood to obtain the effect of α, β, and θ on the total pressure P of the whole machine. t and the total pressure efficiency η, where P t is the sum of the static pressure and dynamic pressure at the outlet of the centrifugal fan, η is the output power / input power of the centrifugal fan, α is the angle between the second end point of the volute of the centrifugal fan and the positive direction of the X-axis of the coordinate system, β is the angle between the first plane of the volute facing the upper cover plate and the upper cover plate, and / or between the second plane of the volute facing the lower cover plate and the lower cover plate, and θ is the angle between the centrifugal fan and the rear cover plate of the fan frame; S2. Determine the optimal range of α, β, and θ based on single factor analysis.

8. The range hood design method according to claim 7, wherein: Step S2 specifically includes: Based on the above influence relationship, the Box-Beknken experimental design is used to obtain the influence of α, β and θ on the total pressure P of the whole machine. t The three-variable linear regression equation of total pressure efficiency η is: P t =81.36+0.5475α-0.5925β+1.37θ; η=33.02-0.0984α+0.027β+0.5689θ.

9. The range hood design method according to claim 8, wherein: When calculating the ternary linear regression equation, the method of large sample size is adopted for optimization.

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