Protruding part design method of air-blowing optical cable based on air pushing compensation and air-blowing optical cable

Abstract

The invention provides a convex part design method of an air-blowing optical cable based on air pushing compensation and the air-blowing optical cable, the optical cable comprises a circular cable body, a plurality of convex parts are uniformly distributed on the cable body in the circumferential direction, a concave part is formed between two adjacent convex parts, the contour of each convex part is in a semi-elliptical shape, and two end points of the semi-elliptical shape in the tangential direction of the cable body are located on a dedendum circle. The convex part design method comprises the following steps that an air-blowing compensation coefficient of the optical cable is introduced, the lower limit of the air-blowing compensation coefficient is close to the minimum value of the ratio of the friction force per unit length of the optical cable to the thrust force per unit length of air, and the upper limit of the air-blowing compensation coefficient is the maximum value of the ratio of the arc length of the convex part to the arc length of the overlapped part of the convex part and a dedendum circle; calculating the minimum number of the convex parts by taking constants in an air-blowing compensation coefficient range; and substituting the minimum number into a calculation formula of the number of the convex parts to obtain a relational expression of the half first axis length and the half second axis length, and selecting a value based on the value range, the step length, the relational expression and the demand of the half first axis length and the half second axis length.

Description

Technical Field

[0001] The present invention relates to the technical field of air-blown optical cables, and in particular to a convex portion design method of an air-blown optical cable based on air-push compensation and the air-blown optical cable. Background Art

[0002] In air-blowing cable technology, optical cables are fed into pipelines via high-pressure airflow. During this process, the cables are subjected to both gas thrust and friction. The core mechanical equilibrium condition for this process is that the gas thrust is greater than or equal to the friction. If the gas thrust is insufficient, the optical cable may become stuck, reducing installation efficiency and even damaging the cable sheath.

[0003] When designing optical cables for large-mass or long-distance installations, traditional methods rely on adding protrusions (such as spiral ribs, corrugated structures, discrete bumps, etc.) to the cable's outer surface to compensate for insufficient gas thrust. However, in actual design, the following problems inevitably arise: the calculation process is complex, there is a lack of universal models, and the design process relies on numerical simulations (such as CFD) or extensive experiments, resulting in low efficiency; thrust compensation lacks a quantitative basis, and the optimization of the protrusion structure is often based on empirical formulas or historical cases, lacking unified design standards and relying heavily on empirical design; and during long-distance installations, accumulated errors can render thrust compensation ineffective, impacting construction efficiency. Therefore, existing thrust compensation technology for air-blown optical cables is still in a semi-empirical stage, and a systematic design theory and standardized methods are urgently needed to improve the reliability and cost-effectiveness of large-mass optical cable installations. Summary of the Invention

[0004] The object of the present invention is to provide a method for designing a convex portion of an air-blown optical cable based on air-push compensation and an air-blown optical cable to solve the above-mentioned problems.

[0005] The technical solution adopted in the present invention is: A method for designing convex parts of an air-blown optical cable based on air-thrust compensation is disclosed. The optical cable comprises a circular cable body with a plurality of convex parts evenly distributed along the circumference of the cable body. A concave part is formed between two adjacent convex parts. The circle on which the cable body lies is the tooth root circle, and the circle formed by the ends of the convex parts away from the cable body is the tooth tip circle. The contour of the convex part is a semi-ellipse, and the two end points of the semi-ellipse in the tangent direction of the cable body are located on the tooth root circle. The design steps are as follows: S1. Introduce air blowing compensation coefficient α 缆 , , ……(one); F 摩 is the friction force per unit length of the optical cable, F 气推 is the thrust per unit length of the gas; ……(two); 凸 is the arc length of a convex part, 重合 It is the arc length of the part where a convex part coincides with the tooth root circle; ……(three); e is the eccentricity of the half ellipse, E(e) is the complete elliptic integral of the second kind, H is the length of the longest axis of the half ellipse in the radial direction of the cable, 0.2mm≤H≤0.4mm, W is half the length of the two endpoints of the half ellipse in the tangent direction of the cable body, 0.15mm≤W≤0.4mm; ……(Four); R 齿根 is the tooth root circle radius; Substitute formulas (3) and (4) into formula (2) to establish a mathematical model of H, W, and α2; set the step size △H = 0.01mm, △W = 0.01mm, traverse the values ​​of H and W and substitute them into the above mathematical model, and take the maximum value of the calculated results as α2; S2. Calculate the minimum number of convex parts N min + ; Number of convex parts ……(five); α0 is a constant between [α1, α2], 缆min is the minimum wet perimeter length of the optical cable; according to the step lengths △H and △W, traverse the values ​​of H and W and substitute them into formula (5), and calculate the minimum value N min Round up to get N min + ; S3.N min + Substituting into formula (5) yields the relationship f(H, W) between H and W. Select the values ​​of H and W based on their range, step size, f(H, W), and requirements.

[0006] As a further improved technical solution of the present invention, ……(six), in, 缆 is the wet perimeter of the optical cable.

[0007] As a further improved technical solution of the present invention, α 缆max =3.

[0008] As a further improved technical solution of the present invention, ……(ten), Among them, λ is the resistance coefficient along the way, ρ 气 is the density of the gas in the pipe, v 气 is the velocity of gas flow, and dl is the unit length.

[0009] As a further improved technical solution of the present invention, , Where Re is the Reynolds number, , Among them, μ 气 is the dynamic viscosity of the gas, , Where ε is the absolute roughness of the inner wall of the pipe.

[0010] As a further improved technical solution of the present invention, ……(eleven), Where G is the weight of the cable, g is the acceleration of gravity, g=9.8m / s 2 , μ is the friction coefficient.

[0011] As a further improved technical solution of the present invention, ……(seven).

[0012] An air-blown optical cable, wherein the convex portion of the optical cable can be designed according to the convex portion design method of an air-blown optical cable based on air push compensation.

[0013] As a further improved technical solution of the present invention, the sum of the areas of all the recesses of the optical cable S 凹 for: ……(nineteen), Among them, R 齿尖 is the radius of the tooth tip circle.

[0014] As a further improved technical solution of the present invention, 5.2673mm 2 ≤S 凹 ≤6.9523mm 2 .

[0015] The beneficial effects of the present invention are: Through the above technical solution, based on the theory of mechanics and fluid dynamics, a universal thrust compensation model was established, and the compensation coefficient α was predicted by the critical thrust threshold. 缆 , according to the compensation coefficient α 缆 Directly linking optical cable parameters with convex structure parameters, quantifying the thrust compensation relationship, providing a standardized design method, reducing manual trial and error costs, simplifying the calculation process, avoiding construction interruptions caused by insufficient thrust, and improving design efficiency and installation success rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic diagram of the forces acting on the optical cable in the pipeline during cable delivery; Figure 2 It is a radial cross-sectional view of the optical cable; Figure 3 It is a structural diagram of the convex part.

[0017] Among them: 1-optical cable, 2-convex part, 3-concave part, 4-gas, 5-pipeline. DETAILED DESCRIPTION

[0018] The present invention will be described in detail below with reference to the specific embodiments shown in the accompanying drawings. However, these embodiments do not limit the present invention, and any structural, methodological, or functional changes made by those skilled in the art based on these embodiments are all within the scope of protection of the present invention.

[0019] If the present invention involves directions (e.g., up, down, left, right, front, back, outside, inside, etc.), the directions involved must be defined. For example, "To clearly express the positions and directions described in this invention, the end closest to the operator is the proximal end, and the end away from the operator is the distal end." Alternatively, the paper can be used as a reference for definition. Of course, if the subsequent description defines the positional relationship between the two by reference, this definition does not need to be included here.

[0020] An air-blown optical cable, such as Figures 2 and 3 As shown, the optical cable 1 is an approximately circular optical cable 1, which includes a cable body with a circular cross-section. A plurality of arc-shaped protrusions 2 are evenly distributed circumferentially on the cable body, and a recess 3 is formed between two adjacent protrusions 2. The circle where the cable body is located is defined as the root circle, and the circle formed by the collection of the ends of the protrusions 2 away from the center of the optical cable 1 is defined as the tooth tip circle. The outline of the protrusion 2 is semi-elliptical and the semi-ellipse partially coincides with the root circle. The above-mentioned partial coincidence is that the two end points of the semi-ellipse in the tangent direction of the cable body are located on the root circle, that is, the outline of the protrusion 2 is semi-elliptical, the semi-ellipse is symmetrical in the radial direction of the root circle, and the two end points of the semi-ellipse farthest from the axis of symmetry are located on the root circle.

[0021] Based on the above-mentioned air-blown optical cable, the present invention provides a convex portion design method of an air-blown optical cable based on air push compensation, the design method comprising the following steps: S1. Introducing an air blowing compensation coefficient α of optical cable 1 缆 , and calculate the air blowing compensation coefficient α 缆 The value range of is: ; Air blowing compensation coefficient α 缆That is, when the size and mass of the optical cable 1 are large, and there is no structure on the optical cable 1 that helps to increase the gas thrust, the gas thrust is less than the friction force and the cable cannot be sent. Therefore, it is necessary to compensate the gas thrust to meet the cable sending condition that the gas thrust is greater than or equal to the friction force. This compensation is determined by the gas blowing compensation coefficient α. 缆 From this we can see that the air blowing compensation coefficient α 缆 The minimum limit value is the ratio of friction force to gas thrust when no structure that helps to increase gas thrust is provided on the optical cable 1.

[0022] therefore, ……(one); Among them, F 摩 is the friction force per unit length of cable 1, F 气推 is the thrust per unit length of gas 4; In the above, the compensation method for gas thrust is to add the aforementioned protrusion 2 on the outer circumference of the optical cable 1, and the gas blowing compensation coefficient α 缆 It is reflected in the size and number of the protrusions 2. Therefore, the air blowing compensation coefficient α 缆 It is also limited by the tight arrangement of the protrusions 2 on the outer circumference of the optical cable 1 .

[0023] therefore, ……(two); in, 凸 is the arc length of the half ellipse corresponding to a convex part 2, 重合 is the arc length of the part where the convex part 2 coincides with the tooth root circle; 凸 The calculation method is: ……(three); in, ; ; Wherein, e is the eccentricity corresponding to the half ellipse where the convex portion 2 is located, E(e) is the complete elliptic integral of the second kind, H is the length of the semi-first axis corresponding to the half ellipse where the convex portion 2 is located, the semi-first axis is the longest axis of the semi-ellipse in the radial direction of the optical cable 1, 0.2mm≤H≤0.4mm, W is the length of the semi-second axis corresponding to the half ellipse where the convex portion 2 is located, 0.15mm≤W≤0.4mm, the second axis is half of the longest axis perpendicular to the semi-first axis in the semi-ellipse, that is, half of the length of the two endpoints of the semi-ellipse in the tangent direction of the cable body; 重合 The calculation method is: ……(Four); Among them, R 齿根 is the radius of the tooth root circle; Substitute formula (3) and formula (4) into formula (2) to establish the mathematical model of H, W and α2; Set the step size △H=0.01mm, △W=0.01mm, and obtain several calculation results of the mathematical model by traversing the values ​​of H and W and substituting them into the above mathematical model. The maximum value of the calculation results is taken as α2.

[0024] The step size is 0.01mm here because if the step size is too large, it will affect the final forming accuracy of the product, which may cause assembly failure or functional defects; and the step size of 0.01mm is set to reserve a buffer margin for uncertain factors in the production process to ensure dimensional consistency during mass production; if the step size is too small, the existing processing equipment cannot meet the processing requirements, but will lead to a decrease in processing stability.

[0025] S2. Calculate the minimum number N of convex parts 2 min + ; Each time a convex portion 2 is added to the circumference of the optical cable 1, the wetted circumference length of the optical cable 1 increases by △ , and △ = 凸 - 重合 , then, the calculation formula for the number N of convex parts 2 is: ……(five); Among them, α0 is a constant between [α1, α2], 缆min is the minimum wet perimeter length of optical cable 1; According to the step lengths △H and △W, by traversing the values ​​of H and W and substituting them into formula (5), several calculation results of formula (5) are obtained, and the minimum value N of the calculation results is min Round up to get the minimum number N of convex parts 2 min + ; When the number of protrusions 2 is at the minimum value, the basic driving force requirements of the air blowing process can be met. From the perspective of mechanical properties, although increasing the number of protrusions 2 can increase the air blowing force on the optical cable 1, it will also increase the dynamic load on the sheath of the optical cable 1. This is because the increase in the number of protrusions 2 will lead to a relative decrease in the volume proportion of a single protrusion 2. Under the condition that the material distribution density remains unchanged, the overall strength of the structure of the protrusions 2 will show a trend of attenuation. In order to cope with uncertain factors in complex construction environments (such as pipeline corner friction, air pressure fluctuations, etc.), as few protrusions 2 as possible should be used under the premise of meeting the air blowing conditions, and the number of protrusions 2 should be gradually increased only when the measured air blowing force is insufficient.

[0026] S3. Obtain the relationship between the half length of the first axis H and the half length of the second axis W; The minimum number N of convex parts 2 min + Substituting into formula (5), we obtain the relationship between the half-first axis length H and the half-second axis length W, f(H, W). Select the values ​​of the half-first axis length H and the half-second axis length W based on the value range of the half-first axis length H, the value range of the half-second axis length W, the step size (△H and △W), f(H, W), and usage requirements.

[0027] At this point, through the above steps, 缆 Take any value α0 within the given range and obtain the minimum number N of convex parts 2 min + , and in N min + The relationship between the semi-first axis length H and the semi-second axis length W under the conditions of α0 is f(H, W). Since the semi-first axis length H and the semi-second axis length W have an initial value range and a value step, the N min + The number of groups of half-first axis length H and half-second axis length W under the conditions of α0, f(H, W) is limited, and each group can meet the air-blowing requirements. Users can select any group from the above data to implement the design of air-blown optical cable according to actual needs and processing technology.

[0028] Regarding the half first axis length H and half second axis length W and their value ranges, if the half first axis length H is less than 0.2 mm, the wetted area of ​​the optical cable 1 in contact with the airflow is 缆If the semi-secondary axis length W is too small, the gas thrust is insufficient to propel the optical cable 1. If the semi-primary axis length H is greater than 0.4mm, current extrusion processes cannot produce a smooth, stable protrusion 2. Furthermore, excessively large semi-primary axis length H can easily cause deformation. While the semi-primary axis length H remains constant, if the semi-secondary axis length W is too small, the protrusion 2 will form a tall, thin structure with an excessively large aspect ratio (H / W). This reduces the curvature radius of the protrusion 2, increases the surface stress concentration factor, and reduces the compressive strength. Once subjected to external forces, the outer surface of the protrusion 2 becomes extremely fragile and easily damaged, potentially causing other structures to rupture. If the semi-secondary axis length W is too large, the specific surface area of ​​the protrusion 2 increases, increasing the actual contact area between the optical cable 1 and the pipe 5. This increases the friction between the optical cable 1 and the pipe 5 while maintaining a constant dynamic friction coefficient. Furthermore, the surface roughness of the optical cable 1 increases, and the gas flow field forms a turbulent separation zone on the leeward side of the protrusion 2, reducing the effective wetted perimeter of the gas 4 and the optical cable 1, affecting the transmission efficiency of the air blowing force.

[0029] Furthermore, the air blowing compensation coefficient α 缆 The parameters of optical cable 1 are as follows: ……(six), in, 缆 is the wet perimeter length of optical cable 1, 缆min The theoretical minimum value is the wetted circumference of the optical cable 1 when there is no convex portion 2, that is, the circumference of the tooth root circle of the optical cable 1: ……(seven), In the above steps, we can calculate 凸 and 重合 The maximum value of the ratio is α2. To save calculation time, 凸 and 重合 The ratio is simplified to , it can be calculated that , considering the curvature of the convex portion 2, the limit value of α2 can be taken as about 3.

[0030] Considering the actual production process, if the protrusions 2 are designed too compactly, in actual production, the roots of adjacent protrusions 2 may fuse during processing. This fused area will destroy the airflow seal and reduce gas thrust, which will not only affect the air blowing effect or even make air blowing impossible, but also cause the protrusions 2 to have an irregular shape, affecting the uniformity and dimensional accuracy of the outer diameter of the optical cable 1, impairing the structural strength of the optical cable 1, and reducing the mechanical properties of the optical cable 1. Therefore, a balance must be struck between process feasibility, structural reliability, and functional realization. α2 = 2.5 is recommended to ensure good yield and performance stability.

[0031] Next, we will calculate α1, as Figure 1 As shown in FIG. 1 , during the air blowing installation of the optical cable 1 , the gas 4 in the pipe 5 is fully developed to form a steady flow state with a stable velocity. According to the force conditions in the pipe 5 , the corresponding fluid microelement force balance equation is established as follows: F 气推 =F 惯 +F 反推 +F 管阻 +F 缆阻 , Among them, F 惯 is the inertial force generated during the flow of gas 4, which can be expressed as follows: , Among them, ρ 气 is the density of gas 4 in pipe 5, A 气 is the cross-sectional area of ​​the gas 4 flowing in the pipe 5, dl is the unit length, dv 气 is the change in the flow rate of gas 4, t is time, and since the gas flow rate is constant, dv 气 =0, so F 惯 =0; F 反推 is the reverse thrust on gas 4, which can be expressed as follows: , Among them, P 气 is the pressure of gas 4 in pipeline 5; F 管阻 is the pipe resistance encountered by gas 4 during its flow, which can be expressed as follows: , in, 管 is the wetted perimeter of pipe 5, τ 管 is the shear stress of pipeline 5; F 缆阻 is the cable resistance encountered by gas 4 during its flow, which can be expressed as follows: , in, 缆 is the wet perimeter of the optical cable 1, τ 缆 is the shear stress of optical cable 1.

[0032] Since the pipe 5 and the optical cable 1 are mostly made of similar thermoplastic materials (such as HDPE, PVC or modified polyolefins), and due to the similar molecular structure and processing technology of the materials, the pipe 5 and the optical cable 1 have similar roughness. Therefore, according to the Coulomb friction model, when the hardness and roughness of the contact surface materials are similar, the dynamic friction coefficient μ tends to be consistent, so that the shear stress between the optical cable 1 and the pipe 5 remains stable during the air blowing process. The shear stresses of the two are also similar, which can be regarded as τ 管 =τ 缆 , so the parameter τ is introduced 均 Instead of τ 管 and τ 缆 The numerical value of .

[0033] Then the above fluid infinitesimal force balance equation can be simplified to: ……(eight).

[0034] Since the gas flow rate is constant, the inertial force generated by the movement of gas 4 is zero. Therefore, the above-mentioned fluid infinitesimal force balance equation is simplified to: , in, 总 express 缆 and 管 sum.

[0035] According to the Darcy-Weisbach formula, , Among them, d h is the hydraulic diameter, λ is the resistance coefficient along the way, , Among them, R h is the water conservancy radius, , Therefore, the above fluid infinitesimal force balance equation can be simplified as: ……(Nine).

[0036] Therefore, the thrust of gas 4 can be deduced as: ……(ten).

[0037] The drag coefficient λ along the path can be calculated based on the Reynolds number Re and the Colebrook formula.

[0038] , Wherein, Re is the Reynolds number. During the air-blown cable installation process, in order to push the optical cable 1 to move in the pipe 5, the air flow velocity is usually high. The diameter of the pipe 5 used by the optical cable 1 is usually large, which will lead to a large Reynolds number. The Reynolds number is usually much greater than 4000, and the air flow is mostly in a turbulent state.

[0039] , Among them, μ 气 is the dynamic viscosity of gas 4, , Wherein, ε is the absolute roughness of the inner wall of the pipe 5 .

[0040] Through the above steps, F can be calculated 气推 .

[0041] When the optical cable 1 is installed in the pipe 5, the friction force per unit length is: ……(eleven), Where: G is the weight of the optical cable 1, g is the acceleration due to gravity, and g is 9.8m / s 2 , μ is the friction coefficient, which is determined according to the material.

[0042] The above calculations give F 摩 With F 气推 The minimum value of the ratio is α 缆 The lower limit of the value of 缆 After the value range of F 气推min With α 缆min The minimum thrust required is obtained by multiplying the product of and to achieve a balance with the friction force.

[0043] The present invention further provides an air-blown optical cable, wherein the convex portion 2 of the optical cable 1 can be designed according to the convex portion design method of an air-blown optical cable based on air push compensation as described above.

[0044] Based on the above calculation method, the sum of the areas of all convex portions 2 can be calculated as 凸 The sum of the areas of all recesses 3 is S 凹 .

[0045] The sum of the areas of all convex portions 2 on the radial cross section is S 凸 is the area A of a single convex portion 2 凸 Multiply by the number N of convex portions 2 .

[0046] The area A of a convex portion 2 凸 The area is similar to that of half an ellipse, but in fact, there is an overlap between the half ellipse and the tooth root circle. Therefore, the actual area A of a convex portion 2 is凸 It is the area of ​​half the ellipse minus the area of ​​the portion where the half ellipse overlaps with the tooth root circle, that is: ……(twelve), Among them, the area of ​​half ellipse is A 半个椭圆 for: ……(Thirteen), The area of ​​the overlapping part A 重合 for: ……(fourteen); Therefore, substituting formula (13) and formula (14) into formula (12) yields: ……(fifteen).

[0047] Therefore, the area S of all the recesses 3 is 凹 The area of ​​the tooth tip circle minus the area of ​​the tooth root circle minus the sum of the areas of all convex parts 2 S 凸 , that is, the area S of all recesses 3 凹 for: ……(sixteen); Area of ​​tooth tip circle S 齿尖 for: ...(seventeen), The area of ​​the tooth root circle S 齿根 for: ……(eighteen); Among them, R 齿尖 is the radius of the tooth tip circle; Then, by substituting formula (15), formula (17), and formula (18) into formula (16), the sum of the areas of all recesses 3 of the optical cable 1, S 凹 for: ……(nineteen).

[0048] Based on the above calculation method, under the condition of meeting the demand for air-blown cable delivery, the wetted perimeter ratio α of the existing large-core optical cable 1 (144 cores and above) is calculated. 缆 , minimum number of teeth N min+ The sum of the areas of all recesses 3 S 凹 The results are shown in the following table:

[0049] From the above table we can see that: 144-core optical cable can use S 凹 The range is 3.9125mm2 ~7.0268mm 2 ; 288 core optical cable can use S 凹 The range is 4.1025mm 2~ 7.0600mm 2 ; 432 core optical cable can use S 凹 The range is 4.4357mm 2 ~7.3966mm 2 ; 864 core optical cable can use S 凹 The range is 5.2673mm 2 ~6.9523mm 2 ; 1008 core optical cable can use S 凹 The range is 5.7821mm 2 ~7.4693mm 2 .

[0050] Therefore, under the condition of meeting the requirements of air blowing cable delivery, the sum of the areas of all recesses 3 can be set to S 凹 The range is 5.2673mm 2 ≤S 凹 ≤6.9523mm 2 More suitable.

[0051] Under the existing processing conditions, the key to optimizing the air blowing cable delivery effect is to reasonably control the total area S of the concave portion 3 on the surface of the optical cable 1. 凹 This parameter needs to be set within an appropriate range. Too large or too small will have an adverse effect on the air blowing performance.

[0052] If the concave area S 凹 If it is too small, it will first be limited by the current high-temperature and high-pressure extrusion process. During the processing, the small spacing between the concave parts 3 will easily cause the materials of the adjacent convex parts 2 to adhere, thereby destroying the structural integrity of the surface of the optical cable 1. Secondly, from the perspective of aerodynamic performance, the insufficient space of the concave parts 3 will reduce the effective cross-sectional area of ​​the airflow channel, reduce the contact wet perimeter of the gas 4 and the optical cable 1, and thus weaken the gas thrust. In addition, S 凹 The small size can be reflected in the insufficient number of recesses 3, so the number N of protrusions on the surface of the optical cable 1 will be large, which will increase the contact points and contact area between the optical cable 1 and the inner wall of the pipe 5, aggravate the adhesion effect between the inner wall of the pipe 5 and the protrusions 2, and further reduce the air blowing efficiency.

[0053] On the contrary, if the concave area S 凹If it is too large, it will also bring a series of problems. Too many recesses 3 will reduce the number of protrusions N, so that a single protrusion 2 needs to bear greater support force and friction stress, which may not only exceed the structural strength limit of the protrusion 2, accelerate the wear of the sheath material, but also affect the stability of the air blowing process. At the same time, an excessively large recess 3 will make the tooth root circle area of ​​the optical cable 1 more likely to directly contact the pipe wall, increasing friction resistance. From the perspective of fluid mechanics, an excessively large recess area S 凹 This reduces the wetted contact area between the airflow and the optical cable 1, reducing the additional thrust generated by the gas 4, making it difficult to balance the frictional resistance of the pipe wall, resulting in a decrease in transmission efficiency. More seriously, if the recess 3 is too high, it will result in insufficient support points, which will reduce the positioning and support of the optical cable 1 in the pipe 5, seriously affecting the air blowing performance.

[0054] Therefore, the air blowing compensation coefficient α obtained by designing this technical solution is 缆 The parameters of the convex portion 2 and the concave portion 3 can meet the existing air-blowing cable delivery requirements for large-core optical cables 1. For optical cables 1 with 1008 cores or more, air-blowing cable delivery is usually not used.

[0055] The convex portion design method of the air-blown optical cable based on air-thrust compensation and the air-blown optical cable provided by the present invention provide a universal thrust compensation model for the laying arrangement of the air-blown optical cable based on the theory of mechanics and fluid dynamics, and predict the air-blowing compensation coefficient α through the critical thrust threshold. 缆 , avoid construction interruption caused by insufficient thrust in advance, reduce rework rate and resource waste. 缆 It directly associates the relevant parameters of the optical cable 1 with the structural parameters of the protrusion 2 (such as shape), clarifies the mathematical relationship between the size and distribution of the protrusion 2 and the gas thrust, provides a standardized parameter matching method, reduces the cost of manual trial and error, simplifies the calculation process, improves design efficiency, avoids the limitations of empirical formulas, and increases the success rate of one-time laying. It provides the industry with a reusable technical framework and achieves comprehensive improvement in efficient calculation, precise compensation, reliable construction, and cost optimization, which is especially suitable for the laying scenario of large-core optical cables 1.

[0056] It should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each implementation method can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0057] The series of detailed descriptions listed above are only specific descriptions of feasible implementation methods of the present invention. They are not intended to limit the scope of protection of the present invention. Any equivalent implementation methods or changes that do not deviate from the technical spirit of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for designing a convex portion of an air-blown optical cable based on air push compensation, characterized in that: The optical cable (1) includes a circular cable body, a plurality of convex parts (2) are evenly distributed on the circumference of the cable body, a concave part (3) is formed between two adjacent convex parts (2), the circle where the cable body is located is the tooth root circle, the circle formed by the ends of the convex parts (2) away from the cable body is the tooth tip circle, the outline of the convex parts (2) is a semi-ellipse and the two end points of the semi-ellipse in the tangent direction of the cable body are located on the tooth root circle, and the design steps are as follows: S1. Introduce air blowing compensation coefficient α 缆 , , ……(one); F 摩 is the friction force per unit length of the optical cable (1), F 气推 is the thrust per unit length of gas (4); ……(two); 凸 is the arc length of a convex part (2), 重合 is the arc length of the portion where a convex portion (2) coincides with the tooth root circle; ……(three); e is the eccentricity of the half ellipse, E(e) is the complete elliptic integral of the second kind, H is the length of the longest axis of the half ellipse in the radial direction of the optical cable (1), 0.2mm≤H≤0.4mm, W is half the length of the two end points of the half ellipse in the tangent direction of the cable body, 0.15mm≤W≤0.4mm; ……(Four); R 齿根 is the tooth root circle radius; Substitute formulas (3) and (4) into formula (2) to establish a mathematical model of H, W, and α2; set the step size △H = 0.01mm, △W = 0.01mm, traverse the values ​​of H and W and substitute them into the above mathematical model, and take the maximum value of the calculated results as α2; S2. Calculate the minimum number N of convex parts (2) min + ; Quantity of convex parts (2) ...(5); α0 is a constant between [α1, α2], 缆min is the minimum wet perimeter length of the optical cable (1); According to the step size △H and △W, traverse the values ​​of H and W and substitute them into formula (5), and calculate the minimum value N min Round up to get N min + ; S3.N min + Substituting into formula (5) yields the relationship f(H, W) between H and W. Select the values ​​of H and W based on their range, step size, f(H, W), and requirements.

2. The method for designing a convex portion of an air-blown optical cable based on air push compensation according to claim 1, characterized in that: ……(six), in, 缆 is the wet perimeter of the optical cable (1).

3. The method for designing a convex portion of an air-blown optical cable based on air push compensation according to claim 2, characterized in that: α2=3。 4. The method for designing a convex portion of an air-blown optical cable based on air push compensation according to claim 1, characterized in that: ……(ten), Among them, λ is the resistance coefficient along the way, ρ 气 is the density of the gas (4) in the pipe (5), v 气 is the velocity of gas (4) flow, and dl is the unit length.

5. The method for designing a convex portion of an air-blown optical cable based on air push compensation according to claim 4, characterized in that: ， Where Re is the Reynolds number, ， Among them, μ 气 is the dynamic viscosity of gas (4), ， where ε is the absolute roughness of the inner wall of the pipe (5).

6. The method for designing a convex portion of an air-blown optical cable based on air push compensation according to claim 1, characterized in that: ……(eleven), Where G is the weight of the optical cable (1), g is the acceleration due to gravity, g=9.8m / s 2 , μ is the friction coefficient.

7. The method for designing a convex portion of an air-blown optical cable based on air push compensation according to claim 1, characterized in that: ……(seven).

8. An air-blown optical cable, characterized in that: The convex portion (2) of the optical cable (1) can be designed according to any one of the convex portion design methods of an air-blown optical cable based on air-push compensation according to claims 1 to 7.

9. The air-blown optical cable according to claim 8, characterized in that: The sum of the areas of all recesses (3) of the optical cable (1) is S 凹 for: ……(nineteen), Among them, R 齿尖 is the radius of the tooth tip circle.

10. The air-blown optical cable according to claim 9, characterized in that: <h2 style=";text-align:left;direction:ltr">5.2673mm<h2 style=";text-align:left;direction:ltr"> 2 <h2 style=";text-align:left;direction:ltr"> ≤S<h2 style=";text-align:left;direction:ltr"> 凹 <h2 style=";text-align:left;direction:ltr"> ≤6.9523mm<h2 style=";text-align:left;direction:ltr"> 2 <h2 style=";text-align:left;direction:ltr"> 。

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