A method for predicting the driving force of pipeline straight pig dynamic operation

Abstract

The present invention relates to a method for predicting the dynamic operating driving force of a pipeline straight-plate pig. The method comprises the following steps: obtaining basic parameters of the pipeline and the straight-plate pig, cyclically executing a driving force prediction process for all straight plates and accumulating the results; first, calculating the equivalent deflection angle, equivalent deflection angular velocity, and equivalent deflection angular acceleration; second, using the straight-plate deformation and deformation rate formulas to calculate the vertical deformation, vertical deformation rate, horizontal deformation, and horizontal deformation rate; and further selecting different calculation formulas for bending force and compression force according to different operating states. The bending force and compression force are then introduced into different driving force prediction formulas to calculate the straight-plate driving force. The instantaneous driving force of the straight-plate pig during dynamic operation is the driving force obtained by the final accumulation. Compared with the prior art, the present invention provides a simple and easy-to-use driving force prediction method. Only one auxiliary test is required. The input parameters can be simply calculated according to the process to achieve high computational efficiency, a wide range of applicable working conditions, and convenient large-scale engineering applications.

Description

Technical Field

[0001] The present invention belongs to the technical field of pigging and detecting oil and gas pipelines, and in particular relates to a method for predicting the dynamic operation driving force of a pipeline straight-plate pig. Background Art

[0002] The booming oil and gas industry is placing higher demands on the equipment supporting pipeline safety management. Pipeline pigging provides a comprehensive understanding of the actual condition of subsea pipelines, effectively identifies defects, and improves pipeline safety management. Pipeline pigging primarily relies on pigs, of which the straight-plate pig is a key type. The straight-plate pig operates by creating an interference fit between its sealing element, the straight plate, and the inner wall of the pipeline. Driven by a fluid-driven pressure differential, the pig operates through friction, cutting away impurities within the pipeline to achieve its cleaning purpose. Blockage is one of the most common and potentially most detrimental issues encountered during pig operation. A stuck pig creates an obstruction within the pipeline, slowing or even blocking the flow of the medium, causing pressure buildup or condensation, and in severe cases, even rendering the entire pipeline useless. Therefore, prior to pigging, it is crucial to understand the driving force required for the straight-plate pig to ensure smooth operation and avoid blockages.

[0003] Before pigging a pipeline, a ball-sending and receiving drum is typically connected to the pipe opening. The ball-sending and receiving drum is a variable diameter pipe. The ball-sending drum facilitates the transition of the pig from a non-interference state to a uniform interference state, while the ball-sending drum operates in the opposite direction. Because the interference state between the pig and the pipeline changes dynamically during this process, the required driving force of the pig also changes dynamically. This is a common operating condition for all pigs, including straight-plate pigs. Predicting the driving force under dynamic operating conditions is crucial to ensure a smooth pigging process. Currently, this technical challenge is primarily addressed through laboratory testing and finite element numerical simulation. However, due to the complexity of the pig and pipeline test systems, and the need for different test systems for different pigging conditions, laboratory testing is unrealistic for large-scale engineering applications. Similarly, numerical simulation methods also require repeated modeling for different operating conditions, requiring high-quality computational personnel and incurring high computational time costs. Therefore, numerical simulation is not a viable solution. Therefore, a simple and reliable method is urgently needed to predict the driving force of straight-plate pigs during dynamic operation. Summary of the Invention

[0004] In order to overcome the defects of the prior art, the present invention provides a method for predicting the dynamic operation driving force of a pipeline straight plate pig.

[0005] To achieve the above object, the technical solution of the present invention is as follows:

[0006] A method for predicting the driving force of a straight-plate pipeline pig during dynamic operation is provided, wherein the pig element is a straight plate, and the pigging function is achieved through interference friction between the straight plate and the pipeline. The method for predicting the instantaneous driving force of the straight-plate pipeline pig during dynamic operation comprises the following steps:

[0007] 1) Obtain the basic parameters of the pipeline and straight pig required for prediction;

[0008] 2) The counting variable i is initially 1, and the instantaneous driving force F of the dynamic operation of the straight pipe pig is d Initially it is 0, and the following 3)-6) operation flow is executed cyclically to calculate the dynamic operation transient driving force F of each straight board. di , each cycle will be the driving force F of the i-th straight plate di Accumulated to F d , the loop execution condition is i≤n(number of straight boards), until the driving forces of all straight boards have been accumulated;

[0009] 3) Calculate the equivalent deflection angle θ of the i-th straight plate b (t), equivalent deflection angular velocity Equivalent deflection angular acceleration

[0010] 4) The equivalent deflection angle θ calculated in 3) is b (t), equivalent deflection angular velocity Substitute the straight plate deformation and deformation rate formula to calculate the vertical deformation δ of the i-th straight plate b (t), vertical deformation rate Horizontal deformation f b (t), horizontal deformation rate

[0011] 5) Determine the operating status of the i-th straight board and select different calculation formulas for bending force and compression force according to the operating status to calculate the bending force F b and compression force F c , in the steep rise stage, select the first bending force calculation formula and the first compression force calculation formula, in the sudden drop stage, select the second bending force calculation formula and the second compression force calculation formula, in the slow drop stage, select the third bending force calculation formula and the third compression force calculation formula, and in the stable stage, select the fourth bending force calculation formula and the fourth compression force calculation formula;

[0012] 6) According to the operating state of the i-th straight plate, the bending force and compression force calculated in 5) are substituted into the dynamic operation instantaneous driving force prediction formula of the straight plate pig to calculate the driving force of the i-th straight plate. The first dynamic operation instantaneous driving force prediction formula is used for calculation in the steep rise stage, sudden drop stage, and slow drop stage, and the first dynamic operation instantaneous driving force prediction formula is used for calculation in the steady state stage;

[0013] 7) The counting variable i>n, the loop ends, and the final accumulated F in 2) d This is the prediction result of the instantaneous driving force of the straight pig in dynamic operation.

[0014] The present invention has the following beneficial effects:

[0015] (1) The method for predicting the dynamic operation driving force of a pipeline straight-plate pipe cleaner described in the present invention provides a semi-empirical formula prediction method for the field of pipeline cleaning technology. By combining a set of experimental reverse deduction of some parameters, the pipeline and straight-plate pipe cleaner parameters are input and the dynamic operation driving force of the pipeline straight-plate pipe cleaner can be simply predicted according to the process. Compared with the laboratory test method and the finite element numerical simulation method, the economic cost and time cost are significantly saved.

[0016] (2) The method for predicting the dynamic operation driving force of a pipeline straight plate pipe cleaner described in the present invention is simple and easy to use. For the same straight plate pipe cleaner, only one test is required to obtain the parameters, which can be repeatedly used for the driving force prediction work under different pipe cleaning conditions. The method has good universality.

[0017] (3) The method for predicting the dynamic operation driving force of a pipeline straight plate pig described in the present invention does not restrict the interference and friction coefficient and has a wide range of applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A schematic diagram of a method for predicting the driving force of a pipeline straight pig in dynamic operation according to the present invention;

[0019] Figure 2 Schematic diagram of the change of the equivalent deflection angle of a single straight plate of the pipe cleaning device of the present invention from the ball barrel to the straight pipe over time;

[0020] Figure 3 Schematic diagram of the four driving state changes of a single straight plate of the pipe cleaning device of the present invention. DETAILED DESCRIPTION

[0021] The present invention is described in further detail below with reference to the accompanying drawings:

[0022] like Figure 1 As shown, the present invention provides a method for predicting the driving force of the dynamic operation of a pipeline straight plate pig, which is characterized in that the pig element is a straight plate, and the pigging function is achieved through the interference friction between the straight plate and the pipeline, such as Figure 2 As shown in FIG, the method for predicting the instantaneous driving force of the dynamic operation of the straight pipe pig includes the following steps:

[0023] 1) Obtain the basic parameters of the pipeline and straight-plate pig required for prediction, including: the number of straight plates n; the length of the free end of the straight plate l, unit: m; the equivalent mass m of n single-plate pigs for a pig with n straight plates, unit: kg; the running speed of the pig is v, unit: m / s; the inclination angle of the inner wall of the ball launcher is θ L , unit: rad; friction coefficient μ; vertical stiffness coefficient E of the straight plate v , unit: N·m -1 ; Horizontal stiffness coefficient E of the straight plate h , unit: N·m -1 , the vertical damping coefficient η of the straight plate v1 and η v2 (η v1 >>η v2 ), unit: N·s·m -1 ; Horizontal damping coefficient η of the straight plate h1 and η h2 (η h1 >>η h2 ), unit: N·s·m -1 ; The relaxation time t required for the damping of the straight plate to reach a steady state s , unit: s; pipeline length L P ,μ is the friction coefficient. Prediction of the vertical stiffness coefficient E of the basic parameters straight plate v , horizontal stiffness coefficient E of the straight plate h , vertical damping coefficient η of the straight plate v1 and η v2 , horizontal damping coefficient η of the straight plate h1 and η h2 , the relaxation time t required for the damping of the straight plate to reach a steady state s , which is characterized by the fact that the parameters are related to the material and thickness of the straight plate of the pig element. For a certain pig, a set of laboratory high-speed pulling tests are required to obtain the driving force-time curve. Several typical points on the curve are selected and substituted into the dynamic operation driving force prediction formula of the straight plate pig of this patent to infer a set of vertical stiffness coefficients E of the straight plate. v , horizontal stiffness coefficient E of the straight plate h , vertical damping coefficient η of the straight plate v1 and η v2 , horizontal damping coefficient η of the straight plate h1 and η h2 , the relaxation time t required for the damping of the straight plate to reach a steady state s Preferably, the vertical parameters and the horizontal parameters can be assumed to be in a proportional relationship to reduce the number of independent parameters.

[0024] 2) The counting variable i is initially 1, and the instantaneous driving force F of the dynamic operation of the straight pipe pig is dInitially it is 0, and the following 3)-6) operation flow is executed cyclically to calculate the dynamic operation transient driving force F of each straight board. di , each cycle will be the driving force F of the i-th straight plate di Accumulated to F d The loop execution condition is i≤n(number of straight boards), until the driving forces of all straight boards have been accumulated.

[0025] 3) Calculate the equivalent deflection angle θ of the i-th straight plate b (t), equivalent deflection angular velocity Equivalent deflection angular acceleration The following formulas (1)-(3) are used for calculation respectively.

[0026] The equivalent deflection angle expression is:

[0027]

[0028] The equivalent deflection angular velocity expression is:

[0029]

[0030] The equivalent deflection angular acceleration expression is:

[0031]

[0032] Among them, θ b (t) is the equivalent deflection angle at time t, unit: rad; is the equivalent deflection angular velocity at time t, unit: rad / s; is the equivalent deflection angular acceleration at time t, unit: rad / s 2 ; v is the running speed of the pig, unit: m / s; θ L is the inclination angle of the inner wall of the serving tube, unit: rad; the free end length l of the straight plate, unit: m.

[0033] 4) The equivalent deflection angle θ calculated in 3) is b (t), equivalent deflection angular velocity Substitute the straight plate deformation and deformation rate formulas and use equations (4)-(7) to calculate the vertical deformation δ of the i-th straight plate. b (t), vertical deformation rate Horizontal deformation f b (t), horizontal deformation rate The expression of vertical deformation is:

[0034] δ b (t) = l - lcosθ b (4)

[0035] The expression of vertical deformation rate is:

[0036]

[0037] The expression of horizontal deformation is:

[0038]

[0039] The expression of horizontal deformation rate is:

[0040]

[0041] Among them, δ b (t) is the vertical deformation, unit: m; is the vertical deformation rate, unit: m / s; f b (t) is the horizontal deformation, unit: m; is the horizontal deformation rate, unit: m / s; v is the running speed of the pipe cleaner, unit: m / s; l is the free end length of the straight plate, unit: m; t is the running time of the pipe cleaner, unit: s.

[0042] 5) If Figure 3 As shown, the running state of the i-th straight board is judged, and different calculation formulas for bending force and compression force are selected according to the running state to calculate the bending force F b and compression force F c In the steep rise stage, the first bending force calculation formula and the first compression force calculation formula are selected; in the sudden drop stage, the second bending force calculation formula and the second compression force calculation formula are selected; in the slow drop stage, the third bending force calculation formula and the third compression force calculation formula are selected; in the stable stage, the fourth bending force calculation formula and the fourth compression force calculation formula are selected. The different bending force and compression force calculation formulas are shown as follows (8)-(15).

[0043] During the steep rise phase:

[0044] The first bending force calculation formula is:

[0045]

[0046] The first compression force calculation formula is:

[0047]

[0048] During the slump phase:

[0049] The second bending force calculation formula is:

[0050] F b (t) = 2E h f(t) (10)

[0051] The second compression force calculation formula is:

[0052] F c (t) = 2E v δ b (t) (11)

[0053] During the descent phase:

[0054] The third bending force calculation formula is:

[0055]

[0056] The third compression force calculation formula is:

[0057]

[0058] During the stabilization phase:

[0059] The fourth bending force calculation formula is:

[0060]

[0061] The fourth compression force calculation formula is:

[0062]

[0063] In the above formula, τ v and τ h The expressions are as follows (16) and (17)

[0064]

[0065]

[0066] Among them, F b (t) is the bending force, unit: N; F c (t) is the compression force, unit: N; δ b (t) is the vertical deformation, unit: m; f b (t) is the horizontal deformation, unit: m; is the vertical deformation rate, unit: m / s; is the horizontal deformation rate, unit: m / s; t is the running time of the pig, unit: s; t s The relaxation time required for the damping of the straight plate to reach a steady state, unit: s; E v is the vertical stiffness coefficient of the straight plate, unit: N·m -1 ;E h is the horizontal stiffness coefficient of the straight plate, unit: N·m -1 , η v1 and η v2 (η v1 >>η v2) is the vertical damping coefficient of the straight plate, unit: N·s·m -1 ;η h1 and η h2 (η h1 >>η h2 ) is the horizontal damping coefficient of the straight plate, unit: N·s·m -1 .

[0067] 6) If Figure 3 As shown, according to the operating state of the i-th straight plate, the bending force and compression force calculated in 5) are brought into the dynamic operation instantaneous driving force prediction formula of the straight plate pipe cleaner to calculate the driving force of the i-th straight plate. The first dynamic operation instantaneous driving force prediction formula (18) is used to calculate the steep rise stage, sudden drop stage, and slow drop stage, and the first dynamic operation instantaneous driving force prediction formula (19) is used to calculate the steady state stage.

[0068]

[0069]

[0070] Among them, F di is the instantaneous driving force of a bar in dynamic operation, N; F b is the bending force, unit: N; F c is the compression force, unit: N; θ b is the equivalent deflection angle, unit: rad; is the equivalent deflection angular acceleration, unit: rad / s 2 θ L is the inclination angle of the inner wall of the ball-serving tube, unit: rad; l is the length of the free end of the straight plate, unit: m; m is the equivalent mass of n single-straight-plate pigs for a pig with n straight plates, unit: kg; g is the acceleration due to gravity, unit: kg·m / s; μ is the friction coefficient.

[0071] 7) The counting variable i>n, the loop ends, and the final accumulated F in 2) d This is the prediction result of the instantaneous driving force of the straight pig in dynamic operation.

[0072] The following is described with specific examples:

[0073] Example 1:

[0074] The state of the straight-plate pipe cleaner at a certain moment that needs to be predicted in this embodiment is: the first three straight plates have entered the straight pipe and are in a stable stage, and the fourth straight plate is about to enter the straight pipe from the ball barrel and is in a steep rising stage.

[0075] 1) Obtain the basic parameters of the pipeline and pig required for prediction: the number of straight plates n = 4, the free end length of the straight plate l = 0.0355 mm, the running speed of the pig v = 1 m / s, and the inclination angle of the inner wall of the ball launcher θ L =π / 9rad, friction coefficient μ=0.2; Based on a set of high-speed pulling test data, the material parameters are obtained by reverse deduction using this patented method. Assuming that the horizontal parameter is 0.1 of the vertical parameter, the vertical stiffness coefficient E of the straight plate is obtained by reverse deduction. v =520N·m -1 , the horizontal stiffness coefficient E of the straight plate h =52N·m -1 , the vertical damping coefficient η of the straight plate v1 =1000N·s·m -1 , η v2 =70N·s·m -1 , the horizontal damping coefficient η of the straight plate h1 =100N·s·m -1 , η h2 =7N·s·m -1 .

[0076] 2) The counting variable i is initially 1, and the instantaneous driving force F of the dynamic operation of the straight pipe pig is d Initially it is 0, and the following 3)-6) operation flow is executed cyclically to calculate the dynamic operation transient driving force F of each straight board. di , each cycle will be the driving force F of the i-th straight plate di Accumulated to F d , the loop execution condition is i≤4, until all the cantilever driving forces have been accumulated.

[0077] 3) Calculate the equivalent deflection angle θ of the i-th straight plate b (t), equivalent deflection angular velocity Equivalent deflection angular acceleration

[0078] 4) The equivalent deflection angle θ calculated in 3) is b (t), equivalent deflection angular velocity Substitute the straight plate deformation and deformation rate formula to calculate the vertical deformation δ of the i-th straight plate b (t), vertical deformation rate Horizontal deformation f b (t), horizontal deformation rate

[0079] 5) Determine the operating status of the i-th straight board and select different calculation formulas for bending force and compression force according to the operating status to calculate the bending force F b and compression force F cFor the first three cycles corresponding to i=1-3, the straight board is in a stable stage. The fourth bending force calculation formula and the fourth compression force calculation formula are used to calculate the bending force F. b and compression force F c For the cycle i=4, the fourth straight board is in the steep rising stage, and the first bending force calculation formula and the first compression force calculation formula are used to calculate the bending force F b and compression force F c .

[0080] 6) According to the operating state of the i-th straight plate, the bending force and compression force calculated in 5) are substituted into the dynamic operation instantaneous driving force prediction formula of the straight plate pig to calculate the driving force of the i-th straight plate. The first dynamic operation instantaneous driving force prediction formula is used for the steep rise stage, sudden drop stage, and slow drop stage, and the second dynamic operation instantaneous driving force prediction formula is used for the steady state stage. For the first three cycles corresponding to i=1-3, the straight plate is in the stable stage, and the second dynamic operation instantaneous driving force prediction formula is used to calculate the driving force F di For the cycle i=4, the fourth straight board is in the steep rising stage, and the first dynamic operation instantaneous driving force prediction formula is selected to calculate the driving force F di .

[0081] 7) The counting variable i>4, the loop ends, and the final accumulated F in 2) d This is the prediction result of the instantaneous driving force of the straight pig in dynamic operation. The final prediction result of this embodiment is F d =14.22kN.

[0082] Example 2:

[0083] The state of the straight plate pig at a certain moment that needs to be predicted in this embodiment is: all four straight plates have entered the straight pipe and are in a stable stage.

[0084] 1) Obtain the basic parameters of the pipeline and pig required for prediction: the number of straight plates n = 4, the free end length of the straight plate l = 0.0355 mm, the running speed of the pig v = 1 m / s, and the inclination angle of the inner wall of the ball launcher θ L =π / 9rad, friction coefficient μ=0.2; Based on a set of high-speed pulling test data, the material parameters are obtained by reverse deduction using this patented method. Assuming that the horizontal parameter is 0.1 of the vertical parameter, the vertical stiffness coefficient E of the straight plate is obtained by reverse deduction. v =520N·m -1 , the horizontal stiffness coefficient E of the straight plate h =52N·m -1 , the vertical damping coefficient η of the straight plate v1 =1000N·s·m -1 , η v2 =70N·s·m-1 , the horizontal damping coefficient η of the straight plate h1 =100N·s·m -1 , η h2 =7N·s·m -1 .

[0085] 2) The counting variable i is initially 1, and the instantaneous driving force F of the dynamic operation of the straight pipe pig is d Initially it is 0, and the following 3)-6) operation flow is executed cyclically to calculate the dynamic operation transient driving force F of each straight board. di , each cycle will be the driving force F of the i-th straight plate di Accumulated to F d , the loop execution condition is i≤4, until all the cantilever driving forces have been accumulated.

[0086] 3) Calculate the equivalent deflection angle θ of the i-th straight plate b (t), equivalent deflection angular velocity Equivalent deflection angular acceleration

[0087] 4) The equivalent deflection angle θ calculated in 3) is b (t), equivalent deflection angular velocity Substitute the straight plate deformation and deformation rate formula to calculate the vertical deformation δ of the i-th straight plate b (t), vertical deformation rate Horizontal deformation f b (t), horizontal deformation rate

[0088] 5) Determine the operating status of the i-th straight board and select different calculation formulas for bending force and compression force according to the operating status to calculate the bending force F b and compression force F c For all four cycles corresponding to i=1-4, the straight board is in a stable stage. The fourth bending force calculation formula and the fourth compression force calculation formula are used to calculate the bending force F. b and compression force F c .

[0089] 6) According to the operating state of the i-th straight plate, the bending force and compression force calculated in 5) are substituted into the dynamic operation instantaneous driving force prediction formula of the straight plate pig to calculate the driving force of the i-th straight plate. The first dynamic operation instantaneous driving force prediction formula is used for the steep rise stage, sudden drop stage, and slow drop stage, and the second dynamic operation instantaneous driving force prediction formula is used for the steady state stage. For all four cycles corresponding to i = 1-4, the straight plate is in the stable stage, and the second dynamic operation instantaneous driving force prediction formula is used to calculate the driving force F di .

[0090] 7) The counting variable i>4, the loop ends, and the final accumulated F in 2) d This is the prediction result of the instantaneous driving force of the straight pig in dynamic operation. The final prediction result of this embodiment is F d =5.11kN.

[0091] The above describes the embodiments of the present invention in detail with reference to the accompanying drawings and specific embodiments, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions, and variations of these embodiments within the scope of the principles and technical ideas of the present invention are still within the scope of protection of the present invention.

Claims

1. A method for predicting the driving force of a pipeline straight pig in dynamic operation, characterized in that: The pigging element is a straight plate, which realizes the pigging function through the interference friction between the straight plate and the pipeline. The method for predicting the instantaneous driving force of the straight plate pig in dynamic operation includes the following steps: 1) Obtain the basic parameters of the pipeline and straight pig required for prediction; 2) The counting variable i is initially 1, and the instantaneous driving force F of the dynamic operation of the straight pipe pig is d Initially it is 0, and the following 3)-6) operation flow is executed cyclically to calculate the dynamic operation transient driving force F of each straight board. di , each cycle will be the driving force F of the i-th straight plate di Accumulated to F d , the loop execution condition is i≤n, until all the cantilever driving forces have been accumulated; 3) Calculate the equivalent deflection angle θ of the i-th straight plate b (t), equivalent deflection angular velocity Equivalent deflection angular acceleration 4) The equivalent deflection angle θ calculated in 3) is b (t), equivalent deflection angular velocity Substitute the straight plate deformation and deformation rate formula to calculate the vertical deformation δ of the i-th straight plate b (t), vertical deformation rate Horizontal deformation f b (t), horizontal deformation rate 5) Determine the operating status of the i-th straight board and select different calculation formulas for bending force and compression force according to the operating status to calculate the bending force F b (t) and compression force F c (t), in the steep rise stage, the first bending force calculation formula and the first compression force calculation formula are selected; in the sudden drop stage, the second bending force calculation formula and the second compression force calculation formula are selected; in the slow drop stage, the third bending force calculation formula and the third compression force calculation formula are selected; in the stable stage, the fourth bending force calculation formula and the fourth compression force calculation formula are selected; 6) According to the operating state of the i-th straight plate, the bending force and compression force calculated in 5) are substituted into the dynamic operation instantaneous driving force prediction formula of the straight plate pig to calculate the driving force of the i-th straight plate. The first dynamic operation instantaneous driving force prediction formula is used for calculation in the steep rise stage, sudden drop stage, and slow drop stage, and the second dynamic operation instantaneous driving force prediction formula is used for calculation in the stable stage; 7) The counting variable i>n, the loop ends, and the final accumulated F in 2) d This is the prediction result of the instantaneous driving force of the straight pig in dynamic operation.

2. The method for predicting the dynamic operation driving force of a pipeline straight plate pig according to claim 1, characterized in that: The basic parameters of the pipeline and straight-plate pig required for the prediction mainly include: the number of straight plates n; the free end length l of the straight plate, unit: m; the equivalent mass m of n single-plate pigs equivalent to a pig with n straight plates, unit: kg; the friction coefficient μ; the running speed of the pig, v, unit: m / s; the inclination angle of the inner wall of the ball launcher, θ L , unit: rad; vertical stiffness coefficient E of the straight plate v , unit: N·m -1 ; Horizontal stiffness coefficient E of the straight plate h , unit: N·m -1 , the vertical damping coefficient η of the straight plate v1 and η v2 (η v1 >>η v2 ), unit: N·s·m -1 ; Horizontal damping coefficient η of the straight plate h1 and η h2 (η h1 >>η h2 ), unit: N·s·m -1 ; The relaxation time t required for the damping of the straight plate to reach a steady state s , unit: s; pipeline length L P , unit: m.

3. The method for predicting the dynamic operation driving force of a pipeline straight plate pig according to claim 1, characterized in that: The predicted basic parameter is the vertical stiffness coefficient E of the straight plate v , horizontal stiffness coefficient E of the straight plate h , vertical damping coefficient η of the straight plate v1 and η v2 , horizontal damping coefficient η of the straight plate h1 and η h2 , the relaxation time t required for the damping of the straight plate to reach a steady state s The parameters are related to the material and thickness of the straight plate of the pig element. For a certain pig, a set of laboratory high-speed pulling tests need to be carried out to obtain the driving force-time curve. 2-6 typical data points on the curve are selected and substituted into the dynamic operation driving force prediction formula of the straight plate pig to infer a set of vertical stiffness coefficients E of the straight plate. v , horizontal stiffness coefficient E of the straight plate h , vertical damping coefficient η of the straight plate v1 and η v2 , horizontal damping coefficient η of the straight plate h1 and η h2 , the relaxation time t required for the damping of the straight plate to reach a steady state s Alternatively, based on the above method, the vertical parameters and the horizontal parameters are set to a proportional relationship to reduce the calculation equations and further reverse the parameters.

4. The method for predicting the dynamic operation driving force of a pipeline straight pig according to claim 1, characterized in that: The equivalent deflection angle θ b (t), equivalent deflection angular velocity Equivalent deflection angular acceleration The expression is as follows: The equivalent deflection angle expression is: The equivalent deflection angular velocity expression is: The equivalent deflection angular acceleration expression is: Among them, θ b (t) The unit is rad; The unit is rad / s; The unit is rad / s 2 ; v is the running speed of the pig, unit: m / s; θ L is the inclination angle of the inner wall of the serving tube, unit: rad; l is the length of the free end of the straight plate, unit: m.

5. The method for predicting the dynamic operation driving force of a pipeline straight plate pig according to claim 1, characterized in that: The straight plate deformation and deformation rate formula are shown below: The expression of vertical deformation is: δ b (t)=l-lcosθ b (t) The expression of vertical deformation rate is: The expression of horizontal deformation is: The expression of horizontal deformation rate is: Among them, δ b (t) is the vertical deformation, unit: m; is the vertical deformation rate, unit: m / s; f b (t) is the horizontal deformation, unit: m; is the horizontal deformation rate, unit: m / s; v is the running speed of the pipe cleaner, unit: m / s; l is the free end length of the straight plate, unit: m; t is the running time of the pipe cleaner, unit: s.

6. The method for predicting the dynamic operation driving force of a pipeline straight plate pig according to claim 1, characterized in that: The calculation formulas for the bending force and the compressive force are as follows: During the steep rise phase: The first bending force calculation formula is: The first compression force calculation formula is: During the slump phase: The second bending force calculation formula is: F b (t)=2E h f b (t) The second compression force calculation formula is: F c (t)=2E v δ b (t) During the descent phase: The third bending force calculation formula is: The third compression force calculation formula is: During the stabilization phase: The fourth bending force calculation formula is: The fourth compression force calculation formula is: In the above formula, τ v and τ h The expression is Among them, F b (t) is the bending force, unit: N; F c (t) is the compression force, unit: N; δ b (t) is the vertical deformation, unit: m; f b (t) is the horizontal deformation, unit: m; is the vertical deformation rate, unit: m / s; is the horizontal deformation rate, unit: m / s; t is the running time of the pig, unit: s; t s The relaxation time required for the damping of the straight plate to reach a steady state, unit: s; E v is the vertical stiffness coefficient of the straight plate, unit: N·m -1 ;E h is the horizontal stiffness coefficient of the straight plate, unit: N·m -1 , η v1 and η v2 (η v1 >>η v2 ) is the vertical damping coefficient of the straight plate, unit: N·s·m -1 ;η h1 and η h2 (η h1 >>η h2 ) is the horizontal damping coefficient of the straight plate, unit: N·s·m -1 .

7. The method for predicting the dynamic driving force of a pipeline straight pig according to claim 1, characterized in that: The first dynamic operation instantaneous driving force prediction formula is as follows: Where, F di is the instantaneous driving force of a bar in dynamic operation, N; F b (t) is the bending force, unit: N; F c (t) is the compression force, unit: N; θ b (t) is the equivalent deflection angle, unit: rad; is the equivalent deflection angular acceleration, unit: rad / s 2 θ L is the inclination angle of the inner wall of the serving tube, unit: rad; l is the length of the free end of the straight plate, unit: m; m is the equivalent mass of n single-straight-plate pigs when the pig has n straight plates, in kg; g is the acceleration due to gravity, in kg·m / s; and μ is the friction coefficient.

8. The method for predicting the dynamic driving force of a pipeline straight pig according to claim 1, characterized in that: The second dynamic operation instantaneous driving force prediction formula is as follows: Where, F di is the instantaneous driving force of a bar in dynamic operation, N; F b (t) is the bending force, unit: N; F c (t) is the compression force, unit: N; θ b (t) is the equivalent deflection angle, unit: rad; l is the length of the free end of the straight plate, unit: m; m is the equivalent mass of n single-straight-plate pigs when the pig has n straight plates, in kg; g is the acceleration due to gravity, in kg·m / s; and μ is the friction coefficient.

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