Oil-free air compressor with high cooling performance

Abstract

The invention discloses an oilless air compressor with high cooling performance, and belongs to the technical field of oilless air compressors, the oilless air compressor comprises an air compressor body, a cooling box is mounted at the top of the air compressor body, an air outlet flow guide cover is mounted on the surface of the cooling box, and a connecting mounting seat is mounted at the joint of the cooling box and the air compressor body; an air cooling mounting shaft is mounted in the position, close to the cooling box, of the air outlet flow guide cover, the surface of the air cooling mounting shaft is sleeved with a first air cooling mounting base, and a heat dissipation air cooler is mounted on the surface of the first air cooling mounting base; the inner wall of the cooling structure is designed to be of a composite curvature continuous structure with an index contraction section, a sine disturbance section and a parabolic export section, the fluid disturbance and heat exchange surface area is remarkably increased, and the overall heat exchange capacity in unit time is improved; a spiral micro-groove turbulent flow structure is introduced to the surface of the sine disturbance section, a micro-scale vortex field is formed, boundary layer disturbance is further excited, local hot spot accumulation is restrained, and equalization of temperature difference distribution is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of oil-free air compressors, and more specifically, it relates to an oil-free air compressor with high cooling performance. Background Art

[0002] As a common compressed gas device in industrial production, air compressors are widely used in fields such as new energy vehicles, numerical control machining, precision spraying, stainless steel grinding, and automated manufacturing;

[0003] With the continuous improvement of the cleanliness requirements of the oil-free compression system in high-end manufacturing, oil-free air compressors have been widely used in precision industries such as automobiles, medical, food, electroplating, and optics due to their characteristics of not generating oil mist pollution. However, the existing oil-free air compressors generally have the following problems in terms of cooling performance:

[0004] First of all, traditional models usually adopt a flow channel structure with a constant cross-section and evenly arranged heat dissipation fins, which cannot be finely optimized for air flow disturbance, boundary layer characteristics, or fluid heat transfer efficiency. This results in the heat transfer capacity per unit time of the heat dissipation components being easily limited during use;

[0005] Secondly, most of the existing fin structures are attached at a fixed angle and cannot be arranged orderly in combination with the wall surface geometric changes or thermal resistance distribution characteristics of the air compressor housing, which easily causes conduction lag in high-temperature areas and then leads to the problem of uneven local heat dissipation;

[0006] Moreover, under high heat flux density conditions, the thermal resistance of the air compressor usually distributes statically along the structural direction and cannot adapt to dynamic temperature gradient changes, which easily leads to problems such as heat accumulation, rapid temperature rise, and poor heat dissipation. Summary of the Invention

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] An oil-free air compressor with high cooling performance, comprising:

[0009] An air compressor body, a cooling box is installed on the top of the air compressor body, an air outlet guide cover is installed on the surface of the cooling box, a connection mounting seat is installed at the connection between the cooling box and the air compressor body, an air-cooled mounting shaft is installed inside the air outlet guide cover close to the cooling box, a first air-cooled mounting seat is sleeved on the surface of the air-cooled mounting shaft, and a heat dissipation air-cooler is installed on the surface of the first air-cooled mounting seat;

[0010] A heat dissipation wall, the heat dissipation wall is installed inside the cooling box, and heat dissipation fins are installed on the surface of the heat dissipation wall;

[0011] Ventilation wall, the ventilation wall is designed in a wavy shape and installed inside the air-cooled installation shaft. A second air-cooled installation seat is installed on the surface of the air-cooled installation shaft. A third air-cooled installation seat is installed below the second air-cooled installation seat. The third air-cooled installation seat and the second air-cooled installation seat are connected to the surface of the air-cooled installation shaft in the same way. A bottom air outlet block is installed at the bottom of the air-cooled installation shaft;

[0012] Further, the cross-sectional shape of the heat dissipation wall is a curved surface designed with a flow disturbance function. The heat dissipation wall is a continuous and differentiable piecewise composite curvature structure along the axial direction whose radius function is spliced by three structure functions in segments, including:

[0013] Exponential contraction section, whose cross-sectional radius satisfies a functional relationship along the axial height, used to guide the gas to accelerate into the middle section, as follows:

[0014] ; (#1)

[0015] Sine disturbance section, whose cross-sectional radius satisfies a functional relationship along the axial height, used to stimulate air flow disturbance and destroy the boundary layer to enhance heat transfer, as follows:

[0016] ; (#2)

[0017] Parabolic derivation section, whose cross-sectional radius satisfies a functional relationship along the axial height, used to achieve flow field rectification and stable derivation, as follows:

[0018] ; (#3)

[0019] The first derivatives of the three functions are continuous at the corresponding splicing points to form an overall smooth surface structure;

[0020] The heat transfer performance index per unit time of the cooling box is calculated by the following integral formula:

[0021] (#4).

[0022] Further, a plurality of micro-groove flow disturbance structures arranged in a spiral shape are provided on the inner wall surface corresponding to the sine disturbance section of the heat dissipation wall. The pitch of each groove is 10-20 mm, the depth is 0.3-1 mm, and the disturbance function parameters satisfy , used to strengthen the boundary layer disturbance and improve the heat transfer ability between the gas and the curved surface.

[0023] Further, the three-segment radius function at the splicing points , not only has continuous function values, but also its first derivative satisfies:

[0024] (#6);

[0025] To ensure smooth continuity of the structural curvature change during physical processing and air flow guiding, and to guarantee stable transition characteristics during the heat field conduction process.

[0026] Furthermore, the thermal resistance function and the local wall thickness function of the structure and the thermal conductivity of the inner wall material satisfy the following relationship:

[0027] ; (#7)

[0028] where is the structural wall thickness change function along the axial direction and is defined as:

[0029] ; (#8)

[0030] To construct the minimum thermal resistance regulation area in the sinusoidal perturbation section and improve the heat flux per unit time.

[0031] Furthermore, the heat dissipation fins are arranged and installed along the axial direction of the heat dissipation wall, the root of the heat dissipation fins is attached to the outer wall of the heat dissipation wall, and the installation angle of the heat dissipation fins satisfies the following functional relationship:

[0032] ; (#9)

[0033] where is the included angle function between the heat dissipation fin and the tangent direction of the outer wall of the cooling box at the axial position and is used to construct the alignment relationship between the heat dissipation fin and the local tangent of the outer wall of the heat dissipation wall; thus, the shortest conduction path of the heat along the minimum section of the thermal resistance function is derived to improve the overall heat release efficiency of the structure and the heat transfer balance of the outer wall.

[0034] Furthermore, the arrangement density of the heat dissipation fins and the thermal resistance function satisfy the following functional relationship:

[0035] ; (#10)

[0036] where is the arrangement density of the heat dissipation fins at the axial position , is the lower limit of the minimum arrangement density, is the density response coefficient, is the maximum thermal resistance in the structure, is the response enhancement coefficient, which is used to form a reinforcement structure layout mechanism with concentrated fin density in the area of extremely small thermal resistance.

[0037] In summary, the present invention has the following beneficial effects:

[0038] By designing the inner wall of the cooling structure as a composite curvature continuous structure of an exponential contraction section, a sine perturbation section, and a parabolic derivation section, the fluid perturbation and heat transfer surface area are significantly enhanced, and the overall heat transfer capacity per unit time is improved;

[0039] A spiral micro-groove flow disturbance structure is introduced on the surface of the sine perturbation section to form a micro-scale eddy current field, further stimulating the boundary layer disturbance and suppressing the accumulation of local hot spots, realizing the equalization of the temperature difference distribution;

[0040] Through the continuity of the first derivative of the three-section structure function at the splicing point, the sudden change of the flow field and the problem of eddy current backflow are effectively avoided. At the same time, through CAD drive and numerically controlled path continuity machining, the structural stability of the product can also be improved;

[0041] By introducing the structural wall thickness function and the inner wall thermal conductivity into the thermal resistance function model, the controllable design of the thermal resistance distribution in the axial direction is realized. A minimum thermal resistance area can be constructed in the sine perturbation section, thereby enhancing the heat conduction ability in the high heat flux density area. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0043] Figure 1 is a schematic structural diagram of the air compressor body of the present invention;

[0044] Figure 2 is a schematic cross-sectional structure diagram of the inside of the cooling box of the present invention;

[0045] Figure 3 is a schematic sectional structure diagram of the heat dissipation wall of the present invention;

[0046] Figure 4 is a schematic diagram of the micro-groove flow disturbance structure installed on the surface of the heat dissipation wall of the present invention.

[0047] In the figure:

[0048] 1. Air compressor body; 2. Cooling box; 3. Air outlet guide cover; 4. Air-cooled installation shaft; 5. Heat dissipation fins; 6. Heat dissipation wall; 7. Connection mounting seat; 8. First air-cooled mounting seat; 9. Heat dissipation air-cooling; 10. Second air-cooled mounting seat; 11. Third air-cooled mounting seat; 12. Bottom air outlet clamping block; 13. Ventilation wall. Detailed implementation mode

[0049] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0050] Embodiment:

[0051] The following is a further detailed description of the present invention in conjunction with the attached Figures 1-4 drawings.

[0052] Please refer to Figures 1-4 , the present invention provides a technical solution: an oil-free air compressor with high cooling performance, as Figures 1-4 shown, including:

[0053] Air compressor body 1, a cooling box 2 is installed on the top of the air compressor body 1, an air outlet guide cover 3 is installed on the surface of the cooling box 2, a connection mounting seat 7 is installed at the connection between the cooling box 2 and the air compressor body 1, an air-cooled installation shaft 4 is installed inside the air outlet guide cover 3 close to the cooling box 2, a first air-cooled mounting seat 8 is sleeved on the surface of the air-cooled installation shaft 4, and a heat dissipation air-cooling 9 is installed on the surface of the first air-cooled mounting seat 8;

[0054] Heat dissipation wall 6, the heat dissipation wall 6 is installed inside the cooling box 2, heat dissipation fins 5 are installed on the surface of the heat dissipation wall 6, and the heat dissipation fins 5 are installed obliquely;

[0055] Ventilation wall 13, the ventilation wall 13 is designed in a wave shape and installed inside the air-cooled installation shaft 4, a second air-cooled mounting seat 10 is installed on the surface of the air-cooled installation shaft 4, a third air-cooled mounting seat 11 is installed below the second air-cooled mounting seat 10, the third air-cooled mounting seat 11 and the second air-cooled mounting seat 10 are connected to the surface of the air-cooled installation shaft 4 in the same way, and a bottom air outlet clamping block 12 is installed at the bottom of the air-cooled installation shaft 4;

[0056] In this embodiment: When the device is actually in use, the heat dissipation air-cooling 9 is carried by the air-cooling installation shaft 4, so that when the heat dissipation air-cooling 9 is in use, it can be fixed through the movable installation of the first air-cooling installation seat 8 and the air-cooling installation shaft 4. During the process of the heat dissipation air-cooling 9 being powered on, the start of the heat dissipation air-cooling 9 is completed, so that the inside of its cooling box 2 can use the air-cooling heat dissipation effect through the heat dissipation air-cooling 9. Moreover, the setting of the bottom air outlet block 12 is used to enable the inside of the air compressor body 1 to be cooled by cold air from the bottom air outlet block 12 through the air-cooling installation shaft 4 when the top of the air-cooling installation shaft 4 penetrates the external air duct through the ventilation wall 13 and the hollow opening of the air-cooling installation shaft 4 itself, so as to achieve another purpose of use. The cooling box 2 as a whole is installed on the surface of the air compressor body 1 through the connection installation seat 7. Therefore, the connection installation seat 7 is also made of soft material to ensure the detachable connection between the cooling box 2 and the air compressor body 1. If it needs to be integrally cast during the casting process, then the connection installation seat 7 can be directly connected to the air compressor body 1 as a strengthening member of the cooling box 2.

[0057] As Figures 1-4 shown, the cross-sectional shape of the heat dissipation wall 6 is a curved surface with a spoiler function design. The heat dissipation wall 6 is a continuous and differentiable segmented composite curvature structure along the axial direction and its radius function is spliced by three structure functions in segments, including:

[0058] An exponential contraction section, whose cross-sectional radius satisfies a functional relationship along the axial height, is used to guide the gas to accelerate into the middle section, as follows:

[0059] ; (#1)

[0060] where is the inner wall radius function of the heat dissipation wall 6 at the axial height position, which is an overall curvature expression spliced by three functions in segments, is the initial radius at the entrance of the heat dissipation structure, used to define the starting size of the exponential contraction section; is the air flow guiding attenuation coefficient, which controls the contraction rate of the inner wall during the exponential contraction in the lower section. This data can be deduced by the radius before and after contraction and the length of the contraction section. The specific process is: given the starting radius , the end radius , the length of the contraction section , substitute into the formula to calculate, or it can also be modeled by a fluid simulation tool. According to the pressure drop trend, velocity field distribution, inlet recirculation length or area under different , select the optimal so that the inlet compression section can quickly compress the air flow without causing flow separation, thereby determining its design value; is the height coordinate of the inner wall in the axial direction and is the independent variable of all functions; is the first structural segment, the exponential contraction segment and the middle segment, and is also the height of the splicing position between the sine perturbation segments;

[0061] For the sine perturbation segment, its cross-sectional radius satisfies a functional relationship along the axial height and is used to excite air flow perturbation and break the boundary layer to enhance heat transfer, as follows:

[0062] ; (#2)

[0063] where is the average radius of the middle sine perturbation segment and is used as a reference for the central position of the sine function perturbation; is the sine perturbation amplitude and determines the fluctuation degree of the turbulent flow structure on the wall shape; is the wave number of the sine perturbation function and controls the frequency of the perturbation curvature in the axial direction; is the phase of the sine function and represents the starting position displacement of the perturbation; is the splicing height position between the sine perturbation segment and the parabolic derivation segment;

[0064] For the parabolic derivation segment, its cross-sectional radius satisfies a functional relationship along the axial height and is used to realize flow field rectification and stable derivation, as follows:

[0065] ; (#3)

[0066] where , , are the quadratic function coefficients of the parabolic derivation segment respectively, where controls the curvature change rate, controls the linear offset, represents the starting radius offset of the curvature of this segment, is the heat transfer performance evaluation value of the heat dissipation wall 6 in the axial interval per unit time. To ensure good continuity of the inner wall curvature at the structural segment splicing, the parameter can be constructed from the output radius value at the end of the sine perturbation segment to form the starting condition of the derivation segment structure based on the sine function output, thereby improving the stability of the flow field derivation; represents the total structural height of the heat dissipation wall 6 in the axial direction, that is, the overall inner wall range from the starting point to the outlet end position;

[0067] The first derivatives of the three functions are continuous at the corresponding splicing points to form an overall smooth surface structure;

[0068] The heat transfer performance index of the heat dissipation wall 6 per unit time is calculated by the following integral formula:

[0069] ; (#4)

[0070] Among them, is the modulation intensity parameter of the th type of spoiler, representing the weight factor of the contribution of the corresponding perturbation to heat transfer enhancement, which is obtained through experiments. Specifically:

[0071] Prepare a control experimental group, apply different spoiler structures to the same thermal structure and classify them;

[0072] At the same time, keep the air velocity, temperature difference, and material consistent, only the spoiler structure is different;

[0073] Measure the local heat flux or heat transfer coefficient, and perform normalization processing to construct:

[0074] ; or ;

[0075] In this way, it is the contribution ratio of the th type of spoiler structure relative to all spoiler structures;

[0076] is the frequency parameter of the th type of perturbation structure in the axial direction, used to describe the periodic change of air flow perturbation; is the phase starting point of the th type of perturbation, corresponding to the initial axial arrangement position of the perturbation structure;

[0077] is the modulation coefficient of the th type of spoiler on the non - linear coupling of local air flow, controlling the influence range of the spoiler on heat dissipation enhancement. It is deduced by the perturbation influence length Back - calculate. By defining the effective length of the th type of spoiler structure in the axial direction that can significantly affect heat enhancement as , then take . Here we give an example. If a certain type of spoiler structure is only effective within 20 mm near , then . If a certain type of guide - groove spoiler can affect the entire structure length of 100 mm, then . The larger

[0078] is, the more local but stronger the influence is; the smaller it is, the wider the influence area but the flatter the distribution; The pressure at the structure inlet is The pressure at is . Substituting the measured pressure value, the actual can be obtained;

[0079] is the slope derivative of the inner wall of the structure at different heights, describing the influence of local curvature on surface area gain and fluid shear rate; is the heat flux function per unit area at the axial position, which can be obtained through an actual heat flow sensor; is the local thermal resistance function per unit area at position , characterizing the heat transfer difficulty of the heat exchange interface under turbulent flow and structural deformation; is the total height of the heat dissipation wall 6 in the axial direction, determining the integration range and the total design length of the structural section;

[0080] In this embodiment: Among them, in the above formula is a piecewise continuous function composed of formulas (#1), (#2) and (#3), specifically:

[0081] ; (#5)

[0082] Among them, is the radius function of the inner wall along the axial direction, which is a continuous function spliced by three structural section functions: When is in the inlet section interval , is an exponential contraction function When is in the middle sine perturbation section , is a sine perturbation function When is in the derivation section , is a parabolic derivation function . The above splicing function is continuous in its domain of definition and is used as the main integral function in the structure input term, used to represent the influence of wall curvature change on heat transfer performance;

[0083] The following is a proof of the detailed formula of this embodiment, so as to intuitively feel the improvement of the heat dissipation efficiency of the heat dissipation wall 6:

[0084] In this embodiment, the structural parameters are set as:

[0085] Inlet radius mm, contraction section exponential coefficient m , Average radius of the sine perturbation section mm, Amplitude mm, Wave number , Phase , Splicing point mm, mm, Derivation section coefficient , Calculated connection value mm, Total structural length mm, The heat performance index per unit time obtained by numerical integration is W. Compared with the traditional straight-wall structure ( W), for the design of the heat dissipation wall 6 in this embodiment, the heat transfer efficiency is increased by about 37.796;

[0086] As Figures 1-4 shown, on the inner wall surface corresponding to the sine perturbation section of the heat dissipation wall 6, there are multiple micro-groove turbulator structures arranged in a spiral shape. The pitch of each groove is 10 - 20 mm, the depth is 0.3 - 1 mm, and the perturbation function parameters satisfy , which is used to strengthen the boundary layer perturbation and improve the heat transfer ability between the gas and the curved surface;

[0087] In this embodiment, the micro-groove turbulator structure can be formed on the inner wall of aluminum alloy or stainless steel by laser etching or CNC machining, or can be integrally generated through CAD modeling in the 3D printing additive manufacturing stage;

[0088] This micro-groove turbulator structure can break the laminar flow characteristics of the near-wall airflow, induce micro-scale eddy current structures, and can superimpose a secondary perturbation mechanism on the basis of the main perturbation of the sine perturbation, thereby effectively improving the energy exchange efficiency of the boundary layer and significantly enhancing the heat transfer flux density between the near-wall gas and the curved surface;

[0089] Moreover, this micro-groove turbulator structure can also weaken the heat accumulation in the local hot spot area. Through the airflow sweeping effect formed by the spiral perturbation, the inner wall temperature distribution can be made more uniform, thereby reducing the peak temperature difference in the high-temperature area, and further enhancing the thermal field stability and heat transfer uniformity of the entire heat dissipation wall 6 during the heat dissipation process;

[0090] We further limit this. On the inner wall surface in the axial interval mm mm) corresponding to the sine perturbation section, there are multiple micro-groove turbulator structures spirally distributed along the axis. Among them, the pitch of each groove is set to 15 mm, the depth is 0.5 mm, the width is 1 mm, and they are evenly distributed in 3 circles centered on the axis;

[0091] The perturbation function is set to =2mm, Wave number , so as to satisfy , which is used to stimulate stable flow disturbance and suppress turbulent separation. The thermal performance simulation results show that, compared with the structure with only a sinusoidal perturbation surface, in this embodiment, through the setting of the micro-groove flow disturbance structure, the average improvement in the heat transfer capacity per unit area can reach about 15%. This structure can be processed and formed by laser etching or 3D printing integrated manufacturing methods.

[0092] As Figures 1-4 shown, the three-segment radius function at the splicing points , not only has continuous function values, but also its first derivative satisfies:

[0093] (#6).

[0094] It is used to ensure that the structural curvature change has smooth continuity during physical processing and air flow guiding, and to ensure the stable transition characteristics during the heat field conduction process;

[0095] In this embodiment, the definitions of the three-segment radius function are as follows:

[0096] Exponential contraction section:

[0097] ;

[0098] Sine perturbation section:

[0099] ;

[0100] Parabolic derivation section:

[0101] ;

[0102] To ensure the derivative continuity, at set:

[0103] ;

[0104] At set:

[0105] ;

[0106] Through the above setting of the derivative continuity matching of the function, the structural curvature forms a geometrically continuous and tangentially consistent diversion channel at the splicing points, effectively avoiding problems such as local flow velocity disorder, flow field backflow or thermal stress concentration caused by structural mutations. At the same time, this derivative continuity facilitates the realization of smooth tool path control in the numerical control manufacturing process, improving the processing accuracy and the structural heat conduction balance, thus ensuring that the term in the thermal performance calculation formula does not have discontinuous jumps.

[0107] As Figures 1-4 shown, the thermal resistance function and the local wall thickness function of the structure and the thermal conductivity of the inner wall material satisfy the following relationship:

[0108] ; (#7)

[0109] where is the structural wall thickness change function in the axial direction and is defined as:

[0110] ; (#8)

[0111] where is the average wall thickness of the sine perturbation section; is the amplitude of the fluctuation modulation, that is, the maximum deviation;

[0112] to construct the minimum thermal resistance regulation area in the sine perturbation section and improve the heat flux per unit time;

[0113] In this embodiment, to construct the local thermal resistance control area of the structure and improve the heat flux efficiency per unit area in the sine perturbation section, the thermal resistance function is no longer a fixed constant but is defined as a function varying with the axis;

[0114] The structural thermal resistance regulation area is limited to the axial range [30 mm, 70 mm] corresponding to the sine perturbation section. In this area, the wall thickness function is defined as: ; its maximum value of 4 mm appears at z = 30 mm and z = 70 mm, and the minimum value of 2 mm appears at the center z = 50 mm. In the inlet and outlet structure areas outside this interval, the wall thickness is a constant value or a linear transition section, which is not involved in the thermal resistance function modeling process;

[0115] To ensure the physical continuity of the thermal conductivity and wall thickness between the thermal resistance regulation section of the structure and its front and rear inlet and outlet sections, a 5 - mm - long transition zone can be set near z = 30 mm and z = 70 mm, and a linear wall thickness gradual change structure is adopted to ensure its manufacturing feasibility and heat transfer stability;

[0116] Thus, a thermal resistance regulation distribution with the minimum thermal resistance in the middle and slow - release heat conduction at both ends is formed, which is beneficial to improving the heat flux density in the middle sine perturbation section and strengthening the local heat exchange ability;

[0117] In the above, by introducing the wall thickness function based on cosine regulation, the thermal resistance function It becomes a distributed parameter jointly driven by the structural shape and material properties, and then a dynamic heat path structure with strong heat transfer in the center and slow heat conduction at the ends is constructed, thus having high engineering feasibility in aspects such as structural manufacturing, thermal control, and performance regulation.

[0118] As Figures 1-4 shown, the heat dissipation fins 5 are arranged and installed along the axial direction of the heat dissipation wall 6. The root of the heat dissipation fin 5 is in contact with the outer wall of the heat dissipation wall 6, and the installation angle of the heat dissipation fin 5 satisfies the following functional relationship:

[0119] ; (#9)

[0120] where is the angle function between the heat dissipation fin 5 and the tangent direction of the outer wall of the cooling box 2 at the axial position , which is used to construct the alignment relationship between the heat dissipation fin 5 and the local tangent of the outer wall of the heat dissipation wall 6; thus, the shortest conduction path of the heat along the minimum section of the thermal resistance function is derived to improve the overall heat release efficiency of the structure and the heat transfer balance of the outer wall;

[0121] In this embodiment, where:

[0122] , in radians. If converted to the angular unit, the value range is (-90°, 90°), representing the direction in which the outer wall of the structure slopes outward at this point;

[0123] is the optimal normal deviation angle at which the fin should be installed, used to fit the tangent direction of the outer surface of the structure to ensure the shortest path of heat flux conduction;

[0124] If the outer wall of a certain area changes violently, is close to the extreme value, and the fin inclination angle is the largest, and key structural reinforcement should be carried out;

[0125] In the middle of the sine perturbation section, it is usually a positive and negative alternating change area, which is the angle modulation sensitive area;

[0126] We substitute a set of structural parameters for calculation, where , , , , , , , , ), the angle , is the area where the outer wall of the heat dissipation wall 6 is closest to being smooth and most conducive to heat release for the mounting angle, and at and regions, with angles of 7.8° and -3.5° respectively, corresponding to the areas with drastic changes in the curvature of the structural wall;

[0127] It should be noted that the actual manufacturing method of the heat dissipation fins 5 is as follows: The angular function is introduced into the CAD 3D modeling system, and the normal mounting angle of each heat dissipation fin 5 is defined by the function drive method. Then, the angle positioning of the fins on the installation base surface is achieved by the numerical control CNC method or the matching contour surface is directly generated during 3D printing to ensure that each fin is tangentially fitted to the tangent direction of its corresponding structural position;

[0128] To enhance the heat flux responsiveness, in the minimum value segment of the thermal resistance function and the minimum area, the fin density can be increased to 1.5 times that of other sections to cooperate with the high heat flux conduction path in this section. And the angular transition between fins is controlled by the continuity of the angular function to form a "thermal conduction funnel-like" structure, so that the heat conduction path can quickly connect from the high point of the internal heat flow to the strongest heat generation section of the heat dissipation fins;

[0129] Explanations are needed for each character in the formula:

[0130] is the optimal installation inclination angle of the heat dissipation fin at the structural axial position , is the current structural axial position, in mm, which is the axial distance of the structural heat dissipation wall 6 along the mainstream direction; is the initial outer contour radius of the exponential contraction section; represents the air flow channel diameter reduction rate and is the attenuation coefficient of the exponential contraction function; is the radius amplitude of the sine perturbation section; is the initial phase of the sine perturbation section, which determines the perturbation position offset; is the quadratic coefficient of the parabolic derivation section; is the first-order coefficient, and both together with the constant term determine the contour morphology of the structural end; is the symmetry center of the parabolic function.

[0131] As Figures 1-4 shown, the layout density of the heat dissipation fins 5 and the thermal resistance function

[0132] satisfy the following functional relationship:

[0133] where is the layout density of the heat dissipation fins 5 at the axial position ; is the lower limit of the minimum layout density, is the density response coefficient, is the maximum thermal resistance in the structure, γ is the response enhancement coefficient, which is used to form a strengthened structure layout mechanism in which the fin density is concentrated in the area with extremely small thermal resistance;

[0134] In this embodiment, among them, The calculation method of is:

[0135]

[0136] Among them, is the maximum layout density at the minimum thermal resistance point ; is obtained by adjusting through experiments or simulations;

[0137] In this formula (#10), the preferred range of γ is 1.5–2.5, which is used to enhance the density adjustment sensitivity of the section with the smallest thermal resistance, so that the fins form a high-density structure in this area to respond to the maximum heat flux release requirement.

[0138] In the description of this specification, the descriptions referring to terms such as "one embodiment", "example", "specific example", etc. mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0139] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art of this industry should understand that the present invention is not limited by the above embodiments. The above embodiments and the descriptions in the specification only illustrate the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed.

Claims

1. An oil-free air compressor with high cooling performance, characterized in that, Including: An air compressor body (1), on the top of the air compressor body (1) is installed a cooling box (2), on the surface of the cooling box (2) is installed an air outlet guide cover (3), at the connection between the cooling box (2) and the air compressor body (1) is installed a connection mounting seat (7), inside the cooling box (2) near the air outlet guide cover (3) is installed an air-cooling mounting shaft (4), on the surface of the air-cooling mounting shaft (4) is sleeved a first air-cooling mounting seat (8), and on the surface of the first air-cooling mounting seat (8) is installed a heat dissipation air-cooler (9); A heat dissipation wall (6), the heat dissipation wall (6) is installed inside the cooling box (2), and on the surface of the heat dissipation wall (6) are installed heat dissipation fins (5); A ventilation wall (13), the ventilation wall (13) is designed in a wavy shape and installed inside the air-cooling mounting shaft (4), on the surface of the air-cooling mounting shaft (4) is installed a second air-cooling mounting seat (10), below the second air-cooling mounting seat (10) is installed a third air-cooling mounting seat (11), the third air-cooling mounting seat (11) and the second air-cooling mounting seat (10) are connected to the surface of the air-cooling mounting shaft (4) in the same way, and at the bottom of the air-cooling mounting shaft (4) is installed a bottom air outlet clamping block (12).

2. The oil-free air compressor with high cooling performance according to claim 1, characterized in that: The cross-sectional shape of the heat dissipation wall (6) is a curved surface designed with a flow disturbance function, and the heat dissipation wall (6) is in the axial direction is a continuously differentiable piecewise composite curvature structure, and its radius function is pieced together by three structure functions in segments, including: an exponential contraction segment, a sine disturbance segment, and a parabolic derivation segment. The heat transfer performance index per unit time of the cooling box (2) is calculated by the following integral formula: （#4）。 3. The oil-free air compressor with high cooling performance according to claim 2, wherein: On the inner wall surface corresponding to the sine disturbance section of the heat dissipation wall (6) are provided a plurality of micro-groove flow disturbance structures arranged in a spiral shape, which are used to strengthen the boundary layer disturbance and improve the heat transfer ability between the gas and the curved surface.

4. The oil-free air compressor with high cooling performance according to claim 2, characterized in that: The radius function described in the above three paragraphs At the splicing point , , not only the function values are continuous, but also its first-order derivative satisfies: （#6）； It is used to ensure that the structural curvature change has smooth continuity during the physical processing and air flow guiding process, and to ensure the stable transition characteristics during the heat field conduction process.

5. The oil-free air compressor with high cooling performance according to claim 2, wherein: Thermal resistance function and the local wall thickness function of the structure and the thermal conductivity of the inner wall material satisfy the following relationship: （#7）； Among them is the structural wall thickness change function along the axial direction and is defined as: （#8）； To construct a minimum heat resistance regulation area in the sine disturbance section and improve the heat flux per unit time.

6. The oil-free air compressor with high cooling performance according to claim 2, characterized in that: The heat dissipation fins (5) are arranged and installed along the axial direction of the heat dissipation wall (6), the root of the heat dissipation fins (5) is attached to the outer wall of the heat dissipation wall (6), and the installation angle of the heat dissipation fins (5) satisfies the following functional relationship: （#9）； Among them, is the axial position and is the included angle function between the tangent direction of the heat dissipation fin (5) and the outer wall of the cooling box (2) at that position.

7. The oil-free air compressor with high cooling performance according to claim 6, characterized in that: The layout density of the heat dissipation fins (5) and the thermal resistance function satisfy the following functional relationship: （#10）； wherein, is the layout density of the heat dissipation fins (5) at the axial position , is the lower limit of the minimum layout density is the density response coefficient is the maximum thermal resistance in the structure is the response enhancement coefficient, which is used to form a strengthened structure layout mechanism in which the fin density is concentrated in the area with extremely small thermal resistance.

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