Agricultural axial flow fan with guide cone structure

Abstract

The application belongs to the field of mechanical application equipment, and relates to an agricultural axial flow fan with a guide cone structure, which comprises a motor (1), front guide vanes (2), a rotating shaft (3), a hub (4), blades (5), a flow collector (6) and a guide cone (7). The flow collector (6) is a cylinder with equal diameters of an inlet and an outlet. The motor (1) is arranged at the center of the flow collector (6) and is fixed on the wall surface of the flow collector (6) through a motor support. The roots of the four front guide vanes (2) are fixed on the outer wall of the motor (1), and the adjacent front guide vanes (2) are spaced by 90 degrees. The guide cone (7) is fixed on the rear end of the motor (1). The front end of the motor (1) is provided with the rotating shaft (3), and the hub (4) and the rotating shaft (3) are rotatably connected. The roots of the blades (5) are arranged in the grooves reserved in the hub (4) and are fixed on the hub (4). The application can effectively improve the vortex structure of the flow field in the fan and improve the performance of the fan.

Description

Technical Field

[0001] This invention belongs to the field of mechanical application equipment, and specifically relates to an agricultural axial flow fan with a guide cone structure. Background Technology

[0002] Axial flow fans are widely used for ventilation in mines, factories, farms, warehouses, offices, and residences. They are also used for temperature control in systems such as evaporators, condensers, and misting systems. With the widespread application of axial flow fans, their efficiency has become a crucial issue. The actual average operating efficiency of these fans is only 40% to 60%, and some even only 30% to 40%. The low operating efficiency of axial flow fans directly leads to increased energy consumption and waste. Therefore, improving the operating efficiency of these axial flow fans is essential.

[0003] However, current research on axial flow fans is mostly concentrated in the fields of air conditioning and temperature control, and mining. Research on agricultural axial flow fans is relatively limited, and even then, it primarily focuses on optimizing blades, hubs, and hub ratios, with less emphasis on optimizing the outer casing (collector). The collector gradually accelerates the air inside the fan, achieving a uniform and low-loss intake velocity field. Therefore, improving fan performance by optimizing the collector is feasible.

[0004] Although axial flow fans consist of a collector, streamlined shroud (guide cone), front guide vanes, impeller, rear guide vanes, casing, and diffuser, in agricultural applications, manufacturers often omit the guide cone structure to save on manufacturing costs, neglecting its role in improving fan performance. This has resulted in virtually no research on guide cones in the field of agricultural axial flow fans. Therefore, adopting a guide cone design based on the von Kármán curve formula can help improve fan performance. Summary of the Invention

[0005] To address the aforementioned technical problems, the purpose of this invention is to provide an agricultural axial flow fan with a guide cone structure. Through numerical simulation and the establishment of a function model, the length L of the collector inlet section is obtained. W1 Length L of the exit section W2 and the length L of the guide cone D The optimal combination significantly improves the performance of agricultural axial flow fans.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] An agricultural axial flow fan with a guide cone structure includes a motor 1, a front guide vane 2, a rotating shaft 3, a hub 4, blades 5, a collector 6, and a guide cone 7; wherein,

[0008] The collector 6 is a cylinder with the same diameter at both the inlet and outlet; the motor 1 is positioned at the center of the collector 6 and fixed to the wall of the collector 6 via a motor bracket; the roots of four front guide vanes 2 are fixed to the outer wall of the motor 1, with adjacent front guide vanes 2 spaced 90 degrees apart; the guide cone 7 is fixed to the rear end of the motor 1; the front end of the motor 1 is provided with a rotating shaft 3, and the hub 4 is rotatably connected to the rotating shaft 3; the roots of the blades 5 are arranged in a pre-reserved groove in the hub 4 and fixed to the hub 4; wherein,

[0009] The collector length L of collector 6 W and the length L of the guide cone D Determined by the following steps:

[0010] Step S1: Given different collector lengths L of the prototype wind turbine. W Then, modeling is performed, and numerical simulations are conducted on the different fan models to obtain the fan's ventilation volume Q and energy efficiency ratio N. The appropriate collector length L for collector 6 is then selected through numerical simulation. W ;

[0011] Wherein, the distance from the inlet end of the fan to the outlet end of the fan is the collector length L. W Using the front end face of motor 1 as the boundary, the collector length L of collector 6 is... W Divided into inlet section length L W1 and the length L of the exit section W2 Two parts: The distance from the inlet end of the fan to the front end face of motor 1 is the length L of the collector inlet section. W1 The distance from the front end of motor 1 to the outlet end of the fan is the length L of the collector outlet section. W2 Single-factor analysis was performed on these two parts separately, using the fan ventilation volume Q and energy efficiency ratio N as evaluation indicators, to obtain the optimal value ranges for each factor:

[0012] Step S1.1: Given the length L of the collector inlet section W1 Different values ​​correspond to different fan models, and numerical simulations are performed to obtain the fan's ventilation volume Q and energy efficiency ratio N;

[0013] Step S1.2: Given the length L of the collector outlet section W2 Different values ​​correspond to different fan models, and numerical simulations are performed to obtain the fan's ventilation volume Q and energy efficiency ratio N;

[0014] Step S1.3: Based on the numerical simulation results of steps S1.1 and S1.2, select the set of parameters that have the highest ventilation volume Q and energy efficiency ratio N under the same conditions, and finally screen out the suitable inlet section length L of the collector. W1 and the length L of the collector outlet section W2 ;

[0015] Step S2: Given different guide cone lengths L D Based on the known parameter, the radius R of motor 1, the cross-sectional profile of the corresponding guide cone 7 is obtained using the von Kármán curve formula.

[0016] The von Kármán curve formula is as follows:

[0017] Formula 1

[0018] In Formula 1, θ is the angle corresponding to the x-coordinate of the point (x,y), used to determine the y-coordinate, and the unit is radians; L is the x-coordinate of a point on the cross-sectional profile of guide cone 7, in mm; L is the length L of guide cone 7. D The unit is mm; R is the ordinate of a point on the cross-sectional profile of guide cone 7, in mm; R is the radius of motor 1, in mm; π is pi.

[0019] Given the length L of the guide cone D Different values ​​yield the corresponding guide cone cross sections according to the von Kármán curve formula;

[0020] Step S3: Using the cross-sectional profile of the guide cone 7 obtained in step S2, model the fan with different guide cone 7 lengths, and then perform numerical simulation to obtain the fan's ventilation volume Q and energy efficiency ratio N. The appropriate guide cone length L is then selected through numerical simulation. D ;

[0021] Among them, the ventilation volume Q and energy efficiency ratio N obtained from numerical simulation are used as evaluation criteria to evaluate the length L of the guide cone. D Single-factor analysis was performed, and the length L of the guide cone was finally obtained. D The optimal value range;

[0022] Step S4: Using ventilation volume Q and energy efficiency ratio N as optimization objectives, solve the functional model of the installation combination of collector 6 and guide cone 7;

[0023] Step S5: Based on the function model of the collector and guide cone installation combination obtained in step S4, install the collector 6 and guide cone 7 onto the prototype agricultural axial flow fan to obtain the optimal combination fan.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] 1) The agricultural axial flow fan with guide cone structure of the present invention selects a suitable combination structure of collector and guide cone, and through the function model of ventilation volume and energy efficiency ratio with the parameters of the combination structure of collector and guide cone, the ventilation volume and energy efficiency ratio of the fan can be significantly improved.

[0026] 2) Compared with the prototype agricultural axial flow fan, the agricultural axial flow fan with guide cone structure of the present invention can increase the ventilation volume of the agricultural axial flow fan by 7.39% and the energy efficiency ratio by 2.6% under the target working condition (105.38Pa).

[0027] 3) The agricultural axial flow fan with guide cone structure of the present invention can effectively improve the vortex structure of the internal flow field of the fan, reduce the size of the vortex structure at the tail of the inlet motor, reduce the flow loss caused by vortices, and improve the performance of the fan. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the guide cone structure of the agricultural axial flow fan with guide cone structure of the present invention;

[0029] Figure 2a This is a schematic diagram of the agricultural axial flow fan with guide cone structure of the present invention;

[0030] Figure 2b This is a left-side structural schematic diagram of the agricultural axial flow fan with guide cone structure of the present invention;

[0031] Figure 2c This is a front view schematic diagram of the agricultural axial flow fan with guide cone structure of the present invention;

[0032] Figure 3a This is a static pressure-ventilation volume relationship curve of the agricultural axial flow fan with guide cone structure of the present invention.

[0033] Figure 3b This is a graph showing the ventilation volume improvement rate of the agricultural axial flow fan with guide cone structure of the present invention.

[0034] Figure 3c This is a static pressure-energy efficiency ratio curve of the agricultural axial flow fan with guide cone structure of the present invention.

[0035] Figure 3d This is a graph showing the improvement rate of energy efficiency ratio of the agricultural axial flow fan with guide cone structure of the present invention.

[0036] Figure 3e This is a diagram of the internal flow field vortex structure of the agricultural axial flow fan with guide cone structure of the present invention.

[0037] The reference numerals in the attached diagram are as follows: 1. Motor; 2. Front guide vane; 3. Shaft; 4. Hub; 5. Blade; 6. Collector; 7. Guide cone; LW, Collector length; LD, Guide cone length; LW1, Collector inlet section length; LW2, Collector outlet section length; R, Motor radius. Detailed Implementation

[0038] To make the technical features of the present invention clearer, the present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0039] like Figure 2a , Figure 2b and Figure 2c As shown, the agricultural axial flow fan with guide cone structure of the present invention includes a motor 1, front guide vanes 2, a rotating shaft 3, a hub 4, blades 5, a collector 6, and a guide cone 7. The collector 6 is a cylinder with the same diameter at the inlet and outlet; the motor 1 is arranged at the center of the collector 6 and fixed to the wall of the collector 6 by a motor bracket; the roots of the four front guide vanes 2 are fixed to the outer wall of the motor 1, with adjacent front guide vanes 2 spaced 90 degrees apart; the guide cone 7 is fixed to the rear end of the motor 1; the front end of the motor 1 is provided with a rotating shaft 3, and the hub 4 and the rotating shaft 3 are rotatably connected; the roots of the blades 5 are arranged in a pre-reserved groove in the hub 4 and fixed to the hub 4.

[0040] Among them, the collector length L of collector 6 W and the length L of the guide cone D Determined by the following steps:

[0041] Step S1: Given different collector lengths L of the prototype wind turbine. W Then, modeling is performed, and numerical simulations are conducted on the different fan models to obtain the fan's ventilation volume Q and energy efficiency ratio N. The appropriate collector length L for collector 6 is then selected through numerical simulation. W ;

[0042] Wherein, the distance from the inlet end of the fan to the outlet end of the fan is the collector length L. W Using the front end face of motor 1 as the boundary, the collector length L of collector 6 is... W Divided into inlet section length L W1 and the length L of the exit section W2 Two parts: The distance from the inlet end of the fan to the front end face of motor 1 is the length L of the collector inlet section. W1 The distance from the front end of motor 1 to the outlet end of the fan is the length L of the collector outlet section. W2 Single-factor analysis was performed on these two parts separately, using the fan ventilation volume Q and energy efficiency ratio N as evaluation indicators, to obtain the optimal value ranges for each factor:

[0043] Step S1.1: Given the length L of the collector inlet section W1 Different values ​​correspond to different fan models, and numerical simulations are performed to obtain the fan's ventilation volume Q and energy efficiency ratio N;

[0044] Step S1.2: Given the length L of the collector outlet section W2 Different values ​​correspond to different fan models, and numerical simulations are performed to obtain the fan's ventilation volume Q and energy efficiency ratio N;

[0045] Step S1.3: Based on the numerical simulation results of steps S1.1 and S1.2, select the set of parameters that have the highest ventilation volume Q and energy efficiency ratio N under the same conditions, and finally screen out the suitable inlet section length L of the collector. W1 and the length L of the collector outlet section W2 ;

[0046] Step S2: Given different guide cone lengths L D Based on the known parameter, the radius R of motor 1, the cross-sectional profile of the corresponding guide cone 7 is obtained using the von Kármán curve formula.

[0047] The von Kármán curve formula is as follows:

[0048] Formula 1

[0049] In Formula 1, θ is the angle corresponding to the x-coordinate of the point (x,y), used to determine the y-coordinate, and the unit is radians; L is the x-coordinate of a point on the cross-sectional profile of guide cone 7, in mm; L is the length L of guide cone 7. D The unit is mm; R is the ordinate of a point on the cross-sectional profile of guide cone 7, in mm; R is the radius of motor 1, in mm; π is pi.

[0050] Given the length L of the guide cone D Different values ​​yield the corresponding guide cone cross sections according to the von Kármán curve formula;

[0051] Step S3: Using the cross-sectional profile of the guide cone 7 obtained in step S2, model the fan with different guide cone 7 lengths, and then perform numerical simulation to obtain the fan's ventilation volume Q and energy efficiency ratio N. The appropriate guide cone length L is then selected through numerical simulation. D ;

[0052] Among them, the ventilation volume Q and energy efficiency ratio N obtained from numerical simulation are used as evaluation criteria to evaluate the length L of the guide cone. D Single-factor analysis was performed, and the length L of the guide cone was finally obtained. D The optimal value range;

[0053] Step S4: Using ventilation volume Q and energy efficiency ratio N as optimization objectives, solve the functional model of the installation combination of collector 6 and guide cone 7;

[0054] Step S5: Based on the function model of the collector and guide cone installation combination obtained in step S4, install the collector 6 and guide cone 7 onto the prototype agricultural axial flow fan to obtain the optimal combination fan.

[0055] Example

[0056] Step S1: Given different collector lengths L of the prototype wind turbine. W Then, modeling is performed, and numerical simulations are conducted on the different fan models to obtain the fan's ventilation volume Q and energy efficiency ratio N. The appropriate collector length L for collector 6 is then selected through numerical simulation. W ;

[0057] A 550mm cylindrical agricultural axial flow fan (referred to as the prototype fan). The prototype fan has an inlet and outlet diameter (also the collector diameter) of 550mm, a total length (also the collector length) of 300mm, a motor diameter of 125mm, and a hub diameter of 98mm.

[0058] Under the target operating conditions (static pressure 105.38 Pa, speed 1435 r / min), the prototype fan has a ventilation volume Q of 5401.47 m³ / min. 3 / h, energy efficiency ratio N is 9.23m 3 / (h·W).

[0059] Among them, the collector length L is defined by taking the front end face of motor 1 as the boundary. W Divided into collector inlet section length L W1 and the length L of the collector outlet section W2 Two parts, such as Figure 2b As shown, single-factor analyses were performed on these two parts respectively, using the fan ventilation volume Q and energy efficiency ratio N as evaluation indicators, to obtain the optimal value ranges for each factor:

[0060] Step S1.1: Given the length L of the collector inlet section W1 Different values ​​of 242, 252, 262, 272 and 281 mm were used to model the wind turbine and perform numerical simulations.

[0061] Step S1.2: Given the length L of the collector outlet section W2 The wind turbine was modeled and numerically simulated for different values ​​of 128, 138, 148, 158 and 168 mm.

[0062] Step S1.3: Using the ventilation volume Q and energy efficiency ratio N of the fan obtained from numerical simulation as the screening criteria, under the same conditions, the higher the ventilation volume Q and energy efficiency ratio N, the better the fan performance. Finally, the suitable inlet section length L of the collector is selected. W1 The length is 252mm, and the suitable length range is 242~262mm; the suitable collector outlet section length L W2 The diameter is 148mm, and the suitable range is 138~158mm;

[0063] Step S2: Given different guide cone lengths LD Based on the radius R of motor 1, the corresponding guide cone 7 section profile parameters are calculated using the von Kármán curve formula.

[0064] The von Kármán curve formula is as follows:

[0065] Formula 1

[0066] In Formula 1, θ is the angle corresponding to the x-coordinate of the point (x,y), used to determine the y-coordinate, and the unit is radians; L is the x-coordinate of a point on the cross-sectional profile of guide cone 7, in mm; L is the length L of guide cone 7. D The unit is mm; R is the ordinate of a point on the cross-sectional profile of guide cone 7, in mm; R is the radius of motor 1, in mm; π is pi.

[0067] Given the length L of the guide cone D Different values ​​of 35, 45, 55, 65, 75, 85, 95, and 100 mm were used to obtain the corresponding guide cone sections using the von Kármán curve formula, as shown below. Figure 1 As shown;

[0068] The radius R of motor 1 is 62.5mm;

[0069] Step S3: Using the cross-sectional profile of the guide cone 7 obtained in step S2, model the fan with different guide cone 7 lengths, and then perform numerical simulation to obtain the fan's ventilation volume Q and energy efficiency ratio N. The appropriate guide cone length L is then selected through numerical simulation. D ;

[0070] Among them, the ventilation volume Q and energy efficiency ratio N obtained from numerical simulation are used as evaluation criteria to evaluate the length L of the guide cone. D A single-factor analysis was performed to obtain the appropriate guide cone length L. D The optimal value is 65mm, with a better range of 55~75mm.

[0071] Step S4: Using ventilation volume Q and energy efficiency ratio N as optimization objectives, solve the functional model of the installation combination of collector 6 and guide cone 7;

[0072] Step S5: Based on the function model of the collector and guide cone installation combination obtained in step S4, install the collector 6 and guide cone 7 onto the prototype agricultural axial flow fan to obtain the optimal combination fan.

[0073] The optimal combination parameters for the wind turbine are finally obtained as follows: the length L of the inlet section of collector 6. W1 The length L of the collector outlet section of collector 6 is 252mm. W2 The length of the guide cone is 148mm.D It is 65mm, such as Figures 2a-2c As shown.

[0074] Compared to the prototype fan, the agricultural axial flow fan of this invention achieves a ventilation volume of 5794.02 m³ / min under the target operating conditions (static pressure 105.38 Pa, speed 1435 r / min). 3 / h, an increase of 7.39%; energy efficiency ratio of 9.37m 3 / (h·W), increased by 2.6%, such as Figures 3a-3d As shown, the vortex structure of the internal flow field of the optimal combination fan is as follows: Figure 3e As shown.

Claims

1. An agricultural axial flow fan with a guide cone structure, characterized in that: The agricultural axial flow fan includes a motor (1), a front guide vane (2), a rotating shaft (3), a hub (4), blades (5), a collector (6), and a guide cone (7); among which, The collector (6) is a cylinder with the same diameter at the inlet and outlet; the motor (1) is arranged at the center of the collector (6) and fixed to the wall of the collector (6) by a motor bracket; the roots of the four front guide vanes (2) are fixed to the outer wall of the motor (1), and the adjacent front guide vanes (2) are spaced 90 degrees apart; the guide cone (7) is fixed to the rear end of the motor (1); the front end of the motor (1) is provided with a rotating shaft (3), and the hub (4) and the rotating shaft (3) are rotatably connected; the roots of the blades (5) are arranged in the grooves reserved in the hub (4) and fixed on the hub (4); among them, The collector length L of collector (6) W and the length L of the guide cone D Determined by the following steps: Step S1: Given different collector lengths L of the prototype wind turbine. W Then, modeling is performed, and numerical simulations are conducted on the different fan models to obtain the fan's ventilation volume Q and energy efficiency ratio N. The appropriate collector length L of the collector (6) is selected through numerical simulation. W ; Wherein, the distance from the inlet end of the fan to the outlet end of the fan is the collector length L. W Using the front end face of the motor (1) as the boundary, the collector length L of the collector (6) is... W Divided into inlet section length L W1 and the length L of the exit section W2 Two parts: The distance from the inlet end of the fan to the front end face of the motor (1) is the length L of the collector inlet section. W1 The distance from the front end of the motor (1) to the outlet end of the fan is the length L of the collector outlet section. W2 Single-factor analysis was performed on these two parts separately, using the fan ventilation volume Q and energy efficiency ratio N as evaluation indicators, to obtain the optimal value ranges for each factor: Step S1.1: Given the length L of the collector inlet section W1 Different values ​​correspond to different fan models, and numerical simulations are performed to obtain the fan's ventilation volume Q and energy efficiency ratio N; Step S1.2: Given the length L of the collector outlet section W2 Different values ​​correspond to different fan models, and numerical simulations are performed to obtain the fan's ventilation volume Q and energy efficiency ratio N; Step S1.3: Based on the numerical simulation results of steps S1.1 and S1.2, select the set of parameters that have the highest ventilation volume Q and energy efficiency ratio N under the same conditions, and finally screen out the suitable inlet section length L of the collector. W1 and the length L of the collector outlet section W2 ; Step S2: Given different guide cone lengths L D Based on the known parameters of the motor (1) radius R, the cross-sectional profile of the corresponding guide cone (7) is obtained using the von Kármán curve formula; The von Kármán curve formula is as follows: Official 1 In Formula 1, θ is the angle corresponding to the x-coordinate of the point (x,y), used to determine the y-coordinate, and the unit is radians; L is the abscissa of a point on the cross-sectional profile of the guide cone (7), in mm; L is the length L of the guide cone (7). D The unit is mm; R is the ordinate of a point on the cross-sectional profile of the guide cone (7), in mm; R is the radius of the motor (1), in mm; π is pi. Given the length L of the guide cone D Different values ​​yield the corresponding guide cone cross sections according to the von Kármán curve formula; Step S3: Using the cross-sectional profile of the guide cone (7) obtained in step S2, model the fan with different guide cone (7) lengths, and then perform numerical simulation to obtain the fan's ventilation volume Q and energy efficiency ratio N. Select a suitable guide cone length L through numerical simulation. D ; Among them, the ventilation volume Q and energy efficiency ratio N obtained from numerical simulation are used as evaluation criteria to evaluate the length L of the guide cone. D Single-factor analysis was performed, and the length L of the guide cone was finally obtained. D The optimal value range; Step S4: Using ventilation volume Q and energy efficiency ratio N as optimization objectives, solve the functional model of the combined installation of the collector (6) and the guide cone (7); Step S5: Based on the function model of the collector and guide cone installation combination obtained in step S4, install the collector (6) and guide cone (7) onto the prototype agricultural axial flow fan to obtain the optimal combination fan.

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