A method for predicting the driving force of pipeline pigs in dynamic operation

Abstract

The present invention relates to a method for predicting the dynamic operating driving force of a pipeline cup cleaner. The method comprises the following steps: obtaining basic parameters of the pipeline and the cup cleaner, executing a driving force prediction process for all cups in a cycle and accumulating the results. First, the cup deflection angle, deflection angular velocity, and deflection angular acceleration are calculated. Second, the cup deformation and deformation rate formula is used to calculate the cup lip deformation, cup lip deformation rate, cup root deformation, and cup root deformation rate. Different formulas are selected to calculate the cup lip force and cup root force depending on the operating state. Furthermore, the horizontal angle of the lip and its relationship with the inclination angle of the inner wall of the ball barrel are determined, and different formulas are selected for driving force prediction. At the end of the cycle, the accumulated driving force is the instantaneous driving force of the cup cleaner in dynamic operation. Compared with the prior art, the present invention provides a prediction method that only requires parameter calculation according to a process and only requires a single auxiliary test. This method is highly efficient, has a wide range of applicability, and can be applied on a large scale.

Description

Technical Field

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

[0002] In recent years, China's oil and gas industry has flourished, and the mileage of oil and gas pipelines has increased annually. According to the "Medium- and Long-Term Oil and Gas Pipeline Network Plan" issued in 2017 by the National Development and Reform Commission and the National Energy Administration, the total mileage of oil and gas pipelines nationwide is projected to reach 200,000 kilometers by 2030. This booming oil and gas industry has placed higher demands on supporting equipment for oil and gas 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, with the cup pig being the most important type. The cup pig operates by creating an interference fit between its sealing element, the cup, and the inner wall of the pipeline. Driven by a fluid-driven pressure differential, the pig utilizes contact friction to remove impurities within the pipeline, achieving its cleaning purpose. Blockage is one of the most common and most dangerous accidents encountered during pig operation. A stuck pig forms an obstruction within the pipeline, slowing or even blocking the flow of media, 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 to operate the pig to ensure smooth operation and avoid blockages.

[0003] Before pigging a pipeline, a ball-sending and receiving tube is typically connected to the pipe opening. The ball-sending and receiving tube is a variable diameter pipe. The ball-sending tube facilitates the transition of the pig from a non-interference state to a uniform interference state, while the ball-sending tube operates in the opposite direction. Because the interference between the pig and the pipeline changes dynamically during the ball-sending and receiving process, the required driving force of the pig also changes dynamically. Therefore, it is necessary to predict the driving force under dynamic operating conditions before pigging to ensure a smooth pigging process. Currently, this technical problem is mainly 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 face the challenge of repeated modeling for different operating conditions, requiring high-quality computational personnel and high computational time costs. Therefore, numerical simulation is not the optimal solution. Therefore, a simple and reliable method is urgently needed to predict the driving force of a pipe cup pig 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 driving force of the dynamic operation of a pipeline leather cup 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 pipeline cup pig in dynamic operation is characterized in that the pig element is a cup, and the pigging function is achieved through interference friction between the cup and the pipeline. The method for predicting the instantaneous driving force of the dynamic operation of the cup pig comprises the following steps:

[0007] 1) Obtain the basic parameters of the pipeline and 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 cup pig is d Initially it is 0, and the following 3)-6) operation process is executed cyclically to calculate the dynamic operation transient driving force F of each cup. di , each cycle will increase the driving force F of the i-th cup di Accumulated to F d , the loop execution condition is i≤n(number of cups), until all cup driving forces have been accumulated;

[0009] 3) Calculate the deflection angle θ of the i-th leather cup c (t), and then differentiate to obtain the deflection angular velocity and angular acceleration

[0010] 4) The deflection angle θ calculated in 3) is c (t), deflection angular velocity Substitute the deformation and deformation rate formula of the leather cup to calculate the lip deformation of the i-th leather cup δ l (t), deformation rate of the leather cup lip Cup root deformation δ r (t), deformation rate of the leather cup root

[0011] 5) Determine the operating state of the i-th leather cup, and select different calculation formulas for the leather cup lip force and the leather cup root force according to the operating state to calculate the leather cup lip force F cl And the force F at the base of the cup cr , in the steep rise stage, select the first leather cup lip force calculation formula and the first leather cup root force calculation formula; in the sudden drop stage, select the second leather cup lip force calculation formula and the second leather cup root force calculation formula; in the slow drop stage, select the third leather cup lip force calculation formula and the third leather cup root force calculation formula; in the stable stage, select the fourth leather cup lip force calculation formula and the fourth leather cup root force calculation formula;

[0012] 6) According to the angle θ between the lip of the i-th leather cup and the horizontal direction lh(i) In the case of different dynamic operation instantaneous driving force prediction formulas, different formulas are selected and introduced into the cup lip force and cup root force calculated in 5) to predict the driving force F of the i-th cup. di ; For the stable stage, when θ lh (i)>0, the leather cup is in the leather lip contact in the straight tube, and the first dynamic operation instantaneous driving force prediction formula is used. When θ lh (i)=0, the leather cup is in critical contact in the straight tube, and the second dynamic operation instantaneous driving force prediction formula is used. When θ lh (i)<0, the leather cup is in leather-root contact in the straight tube, and the third dynamic operation instantaneous driving force prediction formula is used; for the steep rise stage, sudden drop stage, and slow drop stage, when θ lh (i)≥0, continue to determine the angle θ between the lip of the leather cup and the horizontal direction lh (i) and the inclination angle θ of the inner wall of the ball tube L The size relationship of θ lh (i)-θ L > 0, the leather cup is in contact with the leather lip in the serving tube, and the fourth dynamic operation instantaneous driving force prediction formula is used. If θ lh (i)-θ L = 0, the cup is in critical surface-to-surface contact in the serving tube, and the fifth dynamic operation instantaneous driving force prediction formula is used. If θ lh (i)-θ L <0, the cup is in point-surface critical contact in the serving tube, and the sixth dynamic operation instantaneous driving force prediction formula is used. When θ lh (i)<0, the cup is in contact with the base of the cup in the serving tube, and the seventh dynamic operation instantaneous driving force prediction formula is used;

[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 dynamic operation of the leather cup pipe cleaning device.

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

[0015] (1) The method for predicting the dynamic operation driving force of a pipeline leather cup pipe cleaner described in the present invention provides a semi-empirical formula prediction method for the field of pipeline pipe cleaning technology. By combining a set of experimental reverse deduction of some parameters, the pipeline and leather cup pipe cleaner parameters are input and the dynamic operation driving force of the pipeline leather cup 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 driving force of the dynamic operation of a pipeline leather bowl pipe cleaner described in the present invention is simple and easy to use. For the same leather bowl pipe cleaner, only one test is required to obtain the parameters, which can be repeatedly used for the driving force prediction work of different pipe cleaning conditions. The method has good universality.

[0017] (3) The method for predicting the driving force of the dynamic operation of a pipeline leather cup cleaning device described in the present invention does not limit the interference and friction coefficient, and has a wide range of applications. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0019] Figure 2 This is a schematic diagram of some of the cup parameters and the geometric relationship parameters between the cup and the pipe of the present invention;

[0020] Figure 3 Schematic diagram of possible contact states of a single leather cup of the leather cup pipe cleaner of the present invention in a straight pipe;

[0021] Figure 4 Schematic diagram of possible contact states of a single leather cup of the leather cup pipe cleaner of the present invention in a ball serving barrel;

[0022] Figure 5 Schematic diagram of the four driving state changes of a single leather cup of the pipe cleaning device of the present invention. DETAILED DESCRIPTION

[0023] The present invention is described in further detail below with reference to the accompanying drawings:

[0024] like Figure 1 As shown, the present invention provides a method for predicting the driving force of a pipeline cup pig in dynamic operation, characterized in that the pig element is a cup, and the pigging function is achieved through interference friction between the cup and the pipeline. The method for predicting the instantaneous driving force of the dynamic operation of the cup pig includes the following steps:

[0025] 1) Obtain the basic parameters of the pipeline and cup pig required for prediction, including: the number of cups n; the length of the cup lip L l , unit: m; leather cup root length L r , unit: m; l c is the straight-line distance between the end point of the cup lip and the center of rotation, unit: m; the angle between the lip and the horizontal direction θ lh , unit: rad; angle between the root and the vertical direction θ r , unit: rad; outer diameter of leather cup D c , unit: m; a pig with n leather cups is equivalent to n single-cup pigs with an equivalent mass m, unit: kg; cup density ρ, unit: kg / m 3The speed of the pig is v, unit: m / s; the inclination angle of the inner wall of the ball tube is θ L , unit: rad; friction coefficient μ; lip stiffness coefficient E of the leather cup l , unit: N·m -1 ; Root stiffness coefficient E of the leather cup r , unit: N·m -1 , the damping coefficient of the cup lip η l1 and η l2 (η l1 >>η l2 ), unit: N·s·m -1 ; Damping coefficient η of the root of the leather cup r1 and η r2 (η r1 >>η r2 ), unit: N·s·m -1 ; Relaxation time t required for the damping of the leather cup to reach steady state s , unit: s. Prediction of basic parameters of the cup lip stiffness coefficient E l , the root stiffness coefficient E of the leather cup r , the damping coefficient of the lip of the leather cup η l1 and η l2 , the root damping coefficient η of the leather cup r1 and η r2 , the relaxation time t required for the leather cup damper to reach steady state s , which is characterized by the fact that the parameters are related to the material and thickness of the pigging element cup. 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 brought into the dynamic operation driving force prediction formula of the patented cup pig to infer a set of cup lip stiffness coefficients E. l , the root stiffness coefficient E of the leather cup r , the damping coefficient of the lip of the leather cup η l1 and η l2 , the root damping coefficient η of the leather cup r1 and η r2 , the relaxation time t required for the damping of the leather cup to reach a steady state s Preferably, the parameters of the lip and the root can be assumed to be proportional to reduce the number of independent parameters. Some of the cup parameters and the parameters of the geometric relationship between the cup and the pipe are shown as follows: Figure 2 .

[0026] 2) The counting variable i is initially 1, and the instantaneous driving force F of the dynamic operation of the cup pig is d Initially it is 0, and the following 3)-6) operation process is executed cyclically to calculate the dynamic operation transient driving force F of each cup. di , each cycle will increase the driving force F of the i-th cup diAccumulated to F d The loop execution condition is i≤n(number of cups) until the driving forces of all cups have been accumulated.

[0027] 3) Calculate the deflection angle θ of the i-th leather cup c (t), and then differentiate to obtain the deflection angular velocity and angular acceleration The deflection angle of the leather cup is θ c (t) is calculated using formula (1), the deflection angular velocity and angular acceleration MATLAB is needed for differential solution.

[0028] The equivalent deflection angle expression is:

[0029]

[0030] In the above formula, l c is the straight-line distance between the end point of the cup lip and the center of rotation, and its expression is:

[0031]

[0032] Among them, θ c is the deflection angle, unit: rad; θ lh is the angle between the skin lip and the horizontal direction, unit: rad; θ r θ is the angle between the root and the vertical direction, unit: rad; L is the inclination angle of the inner wall of the ball launcher, unit: rad; v is the running speed of the pig, unit: m / s; t is the running time of the pig, unit: s; l c L is the straight-line distance between the end point of the cup lip and the center of rotation, unit: m; l L is the length of the leather cup lip, unit: m; r The length of the leather cup root, unit: m.

[0033] 4) The deflection angle θ calculated in 3) is c (t), deflection angular velocity Substitute the deformation and deformation rate formula of the leather cup and use equations (3)-(6) to calculate the deformation of the leather cup lip δ l (t), deformation rate of the leather cup lip Cup root deformation δ r (t), deformation rate of the leather cup root The expression of the cup lip deformation is:

[0034]

[0035] The expression of the deformation rate of the cup lip is:

[0036]

[0037] The expression of the deformation of the leather cup root is:

[0038]

[0039] The expression of the deformation rate of the leather cup root is:

[0040]

[0041] in,

[0042] A=L l sin(θ lh )+L r cos(θ r ) (7)

[0043] B=L l cos(θ lh )+L r sin(θ r ) (8)

[0044] Among them, δ l (t) is the deformation of the cup lip, unit: m; is the deformation rate of the leather cup lip, unit: m / s; δ r (t) is the deformation of the leather cup root, unit: m; is the deformation rate of the leather cup root, unit: m / s; θ c is the deflection angle, unit: rad; θ lh is the angle between the skin lip and the horizontal direction, unit: rad; θ r is the angle between the root and the vertical direction, unit: rad; L l L is the length of the leather cup lip, unit: m; r The length of the leather cup root, unit: m.

[0045] 5) If Figure 5 As shown, the operating state of the i-th leather cup is judged, and different calculation formulas for calculating the leather cup lip force and the leather cup root force are selected according to the operating state to calculate the leather cup lip force F cl And the force F at the base of the cup crIn the stable stage, the fourth leather bowl lip force calculation formula and the fourth leather bowl root force calculation formula are selected; in the steep rise stage, the first leather bowl lip force calculation formula and the first leather bowl root force calculation formula are selected; in the sudden drop stage, the second leather bowl lip force calculation formula and the second leather bowl root force calculation formula are selected; in the slow drop stage, the third leather bowl lip force calculation formula and the third leather bowl root force calculation formula are selected. Different leather bowl lip force and leather bowl root force calculation formulas are shown as follows (9)-(16).

[0046] During the steep rise:

[0047] The formula for calculating the force acting on the lip of the first leather cup is:

[0048]

[0049] The formula for calculating the force acting on the root of the first leather cup is:

[0050]

[0051] During the descent phase:

[0052] The formula for calculating the force acting on the lip of the second leather cup is:

[0053] F cl (t) = 2E l δ l (t) (11)

[0054] The formula for calculating the force acting on the root of the second leather cup is:

[0055] F cr (t) = 2E r δ r (t) (12)

[0056] During the descent phase:

[0057] The calculation formula of the force acting on the lip of the third cup is:

[0058]

[0059] The calculation formula for the force acting on the root of the third leather cup is:

[0060]

[0061] During the stabilization phase:

[0062] The calculation formula for the force acting on the lip of the fourth cup is:

[0063]

[0064] The calculation formula for the force at the root of the fourth leather cup is:

[0065]

[0066] In the above formula, τ l and τ r The expressions are as follows (15) and (16)

[0067]

[0068]

[0069] Among them, F cl (t) is the force acting on the lip of the leather cup, unit: N; F cr (t) is the force acting on the base of the leather cup, unit: N; δ l (t) is the deformation of the cup lip, unit: m; δ r (t) is the deformation of the leather cup root, unit: m; is the deformation rate of the leather cup lip, unit: m / s; is the deformation rate of the leather cup root, unit: m / s; t is the running time of the pig, unit: s; t s The relaxation time required for the cup damper to reach steady state, unit: s; E l is the lip stiffness coefficient of the leather cup, unit: N·m -1 ;E r is the root stiffness coefficient of the leather cup, unit: N·m -1 , η l1 and η l2 (η l1 >>η l2 ) is the lip damping coefficient of the leather cup, unit: N·s·m -1 ;η r1 and η r2 (η r1 >>η r2 ) is the root damping coefficient of the leather cup, unit: N·s·m -1 .

[0070] 6) If Figure 3 As shown, according to the angle θ between the lip of the i-th leather cup and the horizontal direction lh (i) In the case of different dynamic operation instantaneous driving force prediction formulas, different formulas are selected and introduced into the cup lip force and cup root force calculated in 5) to predict the driving force F of the i-th cup. di ; For the stable stage, when θ lh (i)>0, the leather cup is in contact with the leather lip in the straight tube, such as Figure 3 As shown in (a), the first dynamic operation instantaneous driving force prediction formula (19) is used. When θ lh (i) = 0, the cup is in critical contact in the straight tube, such as Figure 3 As shown in (b), the second dynamic operation instantaneous driving force prediction formula (20) is used. When θ lh (i)<0, the cup is in contact with the root in the straight tube, such as Figure 3 As shown in (c), the third dynamic operation instantaneous driving force prediction formula (21) is adopted; for the steep rise stage, the sudden drop stage, and the slow drop stage, when θ lh (i)≥0, continue to determine the angle θ between the lip of the leather cup and the horizontal direction lh (i) and the inclination angle θ of the inner wall of the ball tube L The size relationship of θ lh (i)-θ L >0, the leather cup is in contact with the leather lip in the serving tube, such as Figure 4 As shown in (a), the fourth dynamic operation instantaneous driving force prediction formula (22) is used. If θ lh (i)-θ L = 0, the cup is in critical surface-to-surface contact in the serving tube, such as Figure 4 As shown in (b), the fifth dynamic operation instantaneous driving force prediction formula (23) is used. If θ lh (i)-θ L <0, the cup is in point-surface critical contact in the serving tube, such as Figure 4 As shown in (c), the sixth dynamic operation instantaneous driving force prediction formula (24) is used. When θ lh (i)<0, the cup is in contact with the root of the cup in the serving tube, such as Figure 4 As shown in (d), the seventh dynamic operation instantaneous driving force prediction formula (25) is adopted.

[0071]

[0072]

[0073]

[0074]

[0075]

[0076]

[0077]

[0078] In the above formulas, the moment of inertia J A Calculate using the following formula (26)

[0079]

[0080] Contact length L cCalculate using the following formula (27)

[0081]

[0082] Among them, F di is the instantaneous driving force of the dynamic operation of a certain leather cup, N; F cl (t) is the force acting on the lip of the leather cup, unit: N; F cr (t) is the force acting on the base of the leather cup, unit: N; θ c is the deflection angle, unit: rad; is the deflection angular acceleration, unit: rad / s 2 θ L is the inclination angle of the inner wall of the ball barrel, unit: rad; θ lh is the angle between the skin lip and the horizontal direction, unit: rad; θ r is the angle between the root and the vertical direction, unit: rad; L l L is the length of the leather cup lip, unit: m; r is the length of the leather cup root, unit: m; J A is the moment of inertia, unit, kg·m 2 ; x is the integral variable of the leather cup axial position, unit: m; ρ is the leather cup density, unit: kg / m 3 ; m is the equivalent mass of n single-cup pigs when the pig has n cups, in kg; μ is the friction coefficient; L c D is the contact length, unit: m; c is the outer diameter of the leather cup, unit: m; D is the inner diameter of the pipe, unit: m; δ l is the deformation of the leather cup lip, m.

[0083] 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 dynamic operation of the leather cup pipe cleaning device.

[0084] The following is described with specific examples:

[0085] Example 1:

[0086] The state of the leather cup pipe cleaner at a certain moment that needs to be predicted in this embodiment is: the first leather cup has entered the straight pipe and is in a stable stage, and the second leather cup is about to enter the straight pipe from the ball barrel and is in a steep rising stage.

[0087] 1) Obtain the basic parameters of the pipeline and pig required for prediction: the number of cups n = 2, the length of the cup lip L l =0.026m, length of the leather cup root L r =0.022m, angle θ between the skin lip and the horizontal direction lh=6.5°, the angle between the root and the vertical direction is θ r =44°, outer diameter of leather cup D c = 0.206m, the running speed of the cup pipe cleaner is v = 0.02m / s, and the inclination angle of the inner wall of the ball tube is θ L =π / 9rad, friction coefficient μ=0.5; 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 parameters of the leather cup lip are 0.1 of the parameters of the leather cup root, the leather cup lip stiffness coefficient E is obtained by reverse deduction. l =80N·m -1 , leather cup root stiffness coefficient E r =800N·m -1 , damping coefficient η of the cup lip l1 =6N·s·m -1 , η l2 =100N·s·m -1 , damping coefficient η at the root of the leather cup r1 =60N·s·m -1 , η r2 =1000N·s·m -1 .

[0088] 2) The counting variable i is initially 1, and the instantaneous driving force F of the dynamic operation of the cup pig is d Initially it is 0, and the following 3)-6) operation process is executed cyclically to calculate the dynamic operation transient driving force F of each cup. di , each cycle will increase the driving force F of the i-th cup di Accumulated to F d , the loop execution condition is i≤2, until all cup driving forces have been accumulated.

[0089] 3) Calculate the deflection angle θ of the i-th leather cup c (t), and then differentiate to obtain the deflection angular velocity and angular acceleration

[0090] 4) The deflection angle θ calculated in 3) is c (t), and then differentiate to obtain the deflection angular velocity and angular acceleration Substitute the cup deformation and deformation rate formula to calculate the lip deformation of the i-th cup δ l (t), deformation rate of the leather cup lip Cup root deformation δ r (t), deformation rate of the leather cup root

[0091] 5) Determine the operating state of the i-th leather cup, and calculate the leather cup lip force F by selecting different calculation formulas for the leather cup lip force and the leather cup root force according to the operating state.cl And the force F at the base of the cup cr For the first cycle corresponding to i=1, the cup is in a stable stage, and the fourth cup lip force calculation formula and the cup root force calculation formula are used to calculate F cl and F cr For the cycle i=2, the second cup is in the steep rising stage, and the formula for calculating the force on the lip of the first cup and the formula for calculating the force on the root of the first cup are used to calculate F. cl and F cr .

[0092] 6) According to the operating state of the i-th leather cup, the bowl lip force and the leather cup root force calculated in 5) are brought into the dynamic operation instantaneous driving force prediction formula of the leather cup pipe cleaner to calculate the driving force of the i-th leather cup. i=1 corresponds to the first cycle, the leather cup is in the stable stage, and θ lh =6.5°>0, the leather cup is in contact with the leather lip in the straight tube, and the driving force F is calculated using the first dynamic operation instantaneous driving force prediction formula di , for the cycle corresponding to i=2, the second leather cup is in the steep rising stage, θ lh =6.5°>0, and θ lh (i)-θ L =-37.5<0, the cup is in point-surface critical contact in the serving tube, and the driving force F is calculated using the sixth dynamic operation instantaneous driving force prediction formula. di .

[0093] 7) The counting variable i>2, the loop ends, and the final accumulated F in 2) d This is the prediction result of the instantaneous driving force of the dynamic operation of the leather cup pipe cleaner. The final prediction result of this embodiment is F d =2.16kN.

[0094] Example 2:

[0095] The state of the cup pig at a certain moment that needs to be predicted in this embodiment is: all four cups have entered the straight pipe and are in a stable stage.

[0096] 1) Obtain the basic parameters of the pipeline and pig required for prediction: Obtain the basic parameters of the pipeline and pig required for prediction: the number of cups n = 4, the length of the cup lip L l =0.026m, length of the leather cup root L r =0.022m, angle θ between the skin lip and the horizontal direction lh =6.5°, the angle between the root and the vertical direction is θ r =44°, outer diameter of leather cup D c = 0.206m, the running speed of the cup pipe cleaner is v = 2m / s, and the inclination angle of the inner wall of the ball tube is θL =π / 9rad, friction coefficient μ=0.4; 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 parameters of the leather cup lip are 0.1 of the parameters of the leather cup root, the leather cup lip stiffness coefficient E is obtained by reverse deduction. l =80N·m -1 , leather cup root stiffness coefficient E r =800N·m -1 , damping coefficient η of the cup lip l1 =6N·s·m -1 , η l2 =100N·s·m -1 , damping coefficient η at the root of the leather cup r1 =60N·s·m -1 , η r2 =1000N·s·m -1 .

[0097] 2) The counting variable i is initially 1, and the instantaneous driving force F of the dynamic operation of the cup pig is d Initially it is 0, and the following 3)-6) operation process is executed cyclically to calculate the dynamic operation transient driving force F of each cup. di , each cycle will increase the driving force F of the i-th cup di Accumulated to F d , the loop execution condition is i≤4, until all the cup driving forces have been accumulated.

[0098] 3) Calculate the deflection angle θ of the i-th leather cup c (t), and then differentiate to obtain the deflection angular velocity and angular acceleration

[0099] 4) The deflection angle θ calculated in 3) is c (t), and then differentiate to obtain the deflection angular velocity and angular acceleration Substitute the cup deformation and deformation rate formula to calculate the lip deformation of the i-th cup δ l (t), deformation rate of the leather cup lip Cup root deformation δ r (t), deformation rate of the leather cup root

[0100] 5) Determine the operating state of the i-th leather cup, and calculate the leather cup lip force F by selecting different calculation formulas for the leather cup lip force and the leather cup root force according to the operating state. cl And the force F at the base of the cup cr For all four cycles corresponding to i=1-4, the cup is in a stable stage. The fourth cup lip force calculation formula and the cup root force calculation formula are used to calculate F.cl and F cr .

[0101] 6) According to the operation state of the i-th leather cup, the bowl lip force and the leather cup root force calculated in 5) are brought into the dynamic operation instantaneous driving force prediction formula of the leather cup pipe cleaner to calculate the driving force of the i-th leather cup. i = 1-4 corresponds to four cycles. The leather cup is in a stable stage, and θ lh =6.5°>0, the leather cup is in contact with the leather lip in the straight tube, and the driving force F is calculated using the first dynamic operation instantaneous driving force prediction formula di .

[0102] 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 dynamic operation of the leather cup pipe cleaner. The final prediction result of this embodiment is F d =4.46kN.

[0103] 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 cup pig in dynamic operation, characterized in that: The pigging element is a leather cup, which realizes the pigging function through the interference friction between the leather cup and the pipeline. The method for predicting the instantaneous driving force of the leather cup pig in dynamic operation includes the following steps: 1) Obtain the basic parameters of the pipeline and pig required for prediction; 2) The counting variable i is initially 1, and the instantaneous driving force F of the dynamic operation of the cup pig is d Initially it is 0, and the following 3)-6) operation process is executed cyclically to calculate the dynamic operation transient driving force F of each cup. di , each cycle will increase the driving force F of the i-th cup di Accumulated to F d , the loop execution condition is i≤n, until all cup driving forces have been accumulated; 3) Calculate the deflection angle θ of the i-th leather cup c (t), and then differentiate to obtain the deflection angular velocity and angular acceleration 4) The deflection angle θ calculated in 3) is c (t), deflection angular velocity Substitute the deformation and deformation rate formula of the leather cup to calculate the lip deformation of the i-th leather cup δ l (t), deformation rate of the leather cup lip Cup root deformation δ r (t), deformation rate of the leather cup root 5) Determine the operating state of the i-th leather cup, and calculate the leather cup lip force F by selecting different calculation formulas for the leather cup lip force and the leather cup root force according to the operating state. cl And the force F at the base of the cup cr , in the steep rise stage, select the first leather cup lip force calculation formula and the first leather cup root force calculation formula; in the sudden drop stage, select the second leather cup lip force calculation formula and the second leather cup root force calculation formula; in the slow drop stage, select the third leather cup lip force calculation formula and the third leather cup root force calculation formula; in the stable stage, select the fourth leather cup lip force calculation formula and the fourth leather cup root force calculation formula; 6) According to the angle θ between the lip of the i-th leather cup and the horizontal direction lh (i) In the case of different dynamic operation instantaneous driving force prediction formulas, different formulas are selected and introduced into the cup lip force and cup root force calculated in 5) to predict the driving force F of the i-th cup. di ; For the stable stage, when θ lh (i)>0, the leather cup is in the leather lip contact in the straight tube, and the first dynamic operation instantaneous driving force prediction formula is used. When θ lh (i)=0, the leather cup is in critical contact in the straight tube, and the second dynamic operation instantaneous driving force prediction formula is used. When θ lh (i)<0, the leather cup is in leather-root contact in the straight tube, and the third dynamic operation instantaneous driving force prediction formula is used; for the steep rise stage, sudden drop stage, and slow drop stage, when θ lh (i)≥0, continue to determine the angle θ between the lip of the leather cup and the horizontal direction lh (i) and the inclination angle θ of the inner wall of the ball tube L The size relationship of θ lh (i)-θ L > 0, the leather cup is in contact with the leather lip in the serving tube, and the fourth dynamic operation instantaneous driving force prediction formula is used. If θ lh (i)-θ L = 0, the cup is in critical surface-to-surface contact in the serving tube, and the fifth dynamic operation instantaneous driving force prediction formula is used. If θ lh (i)-θ L <0, the cup is in point-surface critical contact in the serving tube, and the sixth dynamic operation instantaneous driving force prediction formula is used. When θ lh (i)<0, the cup is in contact with the base of the cup in the serving tube, and the seventh dynamic operation instantaneous driving force prediction formula is used; 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 dynamic operation of the leather cup pipe cleaning device.

2. The method for predicting the dynamic driving force of a pipeline cup pig according to claim 1, characterized in that: The basic parameters of the pipeline and cup pig required for the prediction mainly include: the number of cups n; the length of the cup lip L l , unit: m; leather cup root length L r , unit: m; l c is the straight-line distance between the end point of the cup lip and the center of rotation, unit: m; the angle between the lip and the horizontal direction θ lh , unit: rad; angle between the root and the vertical direction θ r , unit: rad; outer diameter of leather cup D c , unit: m; a pig with n leather cups is equivalent to n single-cup pigs with an equivalent mass m, unit: kg; cup density ρ, unit: kg / m 3 The speed of the pig is v, unit: m / s; the inclination angle of the inner wall of the ball tube is θ L , unit: rad; friction coefficient μ; lip stiffness coefficient E of the leather cup l , unit: N·m -1 ; Root stiffness coefficient E of the leather cup r , unit: N·m -1 , the damping coefficient of the cup lip η l1 and η l2 (η l1 >>η l2 ), unit: N·s·m -1 ; Damping coefficient η of the root of the leather cup r1 and η r2 (η r1 >>η r2 ), unit: N·s·m -1 ; Relaxation time t required for the damping of the leather cup to reach steady state s , unit: s.

3. The method for predicting the driving force of the dynamic operation of a pipeline cup pig according to claim 1, characterized in that: The lip stiffness coefficient E of the leather cup l , the root stiffness coefficient E of the leather cup r , the damping coefficient of the lip of the leather cup η l1 and η l2 , the root damping coefficient η of the leather cup r1 and η r2 , the relaxation time t required for the leather cup damper to reach steady state s The parameters are related to the material and thickness of the pigging element cup. For a certain pig, a set of laboratory high-speed pulling tests are needed to obtain the driving force-time curve. 2-6 typical points on the curve are selected and inserted into the dynamic driving force prediction formula of the cup pig to infer a set of cup lip stiffness coefficients E. l , the root stiffness coefficient E of the leather cup r , the damping coefficient of the lip of the leather cup η l1 and η l2 , the root damping coefficient η of the leather cup r1 and η r2 , the relaxation time t required for the damping of the leather cup to reach a steady state s Alternatively, the parameters of the lip and the root can be set to a proportional relationship to reduce the calculation equations and further infer the parameters.

4. The method for predicting the driving force of a pipeline cup pig in dynamic operation according to claim 1, characterized in that: The deflection angle θ c (t), the expression is as follows: Deflection angle θ c (t) is expressed as: The straight-line distance l between the end point of the leather cup lip and the rotation center in the above formula is c The expression is: L c =L l 2 +L r 2 +2L l L r cos(θ lh +θ r ) Among them, θ c (t) is the deflection angle, unit: rad; θ lh is the angle between the skin lip and the horizontal direction, unit: rad; θ r θ is the angle between the root and the vertical direction, unit: rad; L is the inclination angle of the inner wall of the ball launcher, unit: rad; v is the running speed of the pig, unit: m / s; t is the running time of the pig, unit: s; l c L is the straight-line distance between the end point of the cup lip and the center of rotation, unit: m; l L is the length of the leather cup lip, unit: m; r The length of the leather cup root, unit: m.

5. The method for predicting the driving force of the dynamic operation of a pipeline cup pig according to claim 1, characterized in that: The formula for the cup deformation and deformation rate is as follows: The expression of the cup lip deformation is: The expression of the deformation rate of the leather cup lip is: The expression of the deformation of the leather cup root is: d r (t)=L r cos(θ r )-L r cos[θ c (t)+θ r ] The expression of the deformation rate of the leather cup root is: in, A=L l sin(θ lh )+L r cos(θ r ) B=L l cos(θ lh )+L r sin(θ r ) In the above formulas, δ l (t) is the deformation of the cup lip, unit: m; is the deformation rate of the leather cup lip, unit: m / s; δ r (t) is the deformation of the leather cup root, unit: m; is the deformation rate of the leather cup root, unit: m / s; θ c (t) is the deflection angle, unit: rad; θ lh is the angle between the skin lip and the horizontal direction, unit: rad; θ r is the angle between the root and the vertical direction, unit: rad; L l L is the length of the leather cup lip, unit: m; r The length of the leather cup root, unit: m.

6. The method for predicting the dynamic driving force of a pipeline cup pig according to claim 1, characterized in that: The calculation formula of the force acting on the lip of the leather cup and the force acting on the root of the leather cup is as follows: In the steep rise stage: The formula for calculating the force acting on the lip of the first leather cup is: The formula for calculating the force acting on the root of the first leather cup is: During the descent phase: The formula for calculating the force acting on the lip of the second leather cup is: F cl (t)=2E l δ l (t) The formula for calculating the force acting on the root of the second leather cup is: F cr (t)=2E r δ r (t) During the descent phase: The calculation formula of the force acting on the lip of the third cup is: The calculation formula for the force acting on the root of the third leather cup is: During the stabilization phase: The calculation formula for the force acting on the lip of the fourth cup is: The calculation formula for the force at the root of the fourth leather cup is: In the above formula, τ l and τ r The expression is Among them, F cl (t) is the force acting on the lip of the leather cup, unit: N; F cr (t) is the force acting on the base of the leather cup, unit: N; δ l (t) is the deformation of the cup lip, unit: m; δ r (t) is the deformation of the leather cup root, unit: m; is the deformation rate of the leather cup lip, unit: m / s; is the deformation rate of the leather cup root, unit: m / s; t is the running time of the pig, unit: s; t s The relaxation time required for the cup damper to reach steady state, unit: s; E l is the lip stiffness coefficient of the leather cup, unit: N·m -1 ;E r is the root stiffness coefficient of the leather cup, unit: N·m -1 , η l1 and η l2 (η l1 >>η l2 ) is the lip damping coefficient of the leather cup, unit: N·s·m -1 ;η r1 and η r2 (η r1 >>η r2 ) is the root damping coefficient of the leather cup, unit: N·s·m -1 .

7. The method for predicting the driving force of the dynamic operation of a pipeline cup pig according to claim 1, characterized in that: The first dynamic operation instantaneous driving force prediction formula to the seventh dynamic operation instantaneous driving force prediction formula are as follows: The first dynamic operation instantaneous driving force prediction formula: The second dynamic operation instantaneous driving force prediction formula: The third dynamic operation instantaneous driving force prediction formula: The fourth dynamic operation instantaneous driving force prediction formula is: The fifth dynamic operation instantaneous driving force prediction formula: The sixth dynamic operation instantaneous driving force prediction formula: Seventh dynamic operation instantaneous driving force prediction formula: In the above formulas, Contact length L c Calculate using the following formula (27) Where, F di is the instantaneous driving force of the dynamic operation of a certain leather cup, N; F cl (t) is the force acting on the lip of the leather cup, unit: N; F cr (t) is the force acting on the base of the cup, unit: N; θ c (t) is the deflection angle, unit: rad; is the deflection angular acceleration, unit: rad / s 2 ; θ L is the inclination angle of the inner wall of the ball barrel, unit: rad; θ lh is the angle between the skin lip and the horizontal direction, unit: rad; θ r is the angle between the root and the vertical direction, unit: rad; L l is the length of the leather cup lip, unit: m; L r is the length of the leather cup root, unit: m; J A is the moment of inertia, unit, kg·m 2 ; x is the integral variable of the leather cup axial position, unit: m; ρ is the density of the leather cup, unit: kg / m 3 ; m is the equivalent mass of n single-cup pigs when the pig has n cups, in kg; μ is the friction coefficient; L c is the contact length, unit: m; D c is the outer diameter of the leather cup, unit: m; D is the inner diameter of the pipe, unit: m; δ l is the deformation of the leather cup lip, m.

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