A super-large-diameter liquid slip ring prototype test device and test method

Abstract

The application provides a super-large-diameter liquid sliding ring prototype test device and a test method. The test device comprises an experimental unit, a monitoring unit and a driving unit. The experimental unit comprises a pressing plate, an ear plate, a stand column and a liquid sliding ring. The liquid sliding ring comprises an outer ring and an inner ring. The inner part of the outer ring is provided with upper and lower medium channels, and the circumferential outer wall is connected with the driving unit through the ear plate. The outer ring is also provided with a medium inlet, and the inner surface of the stand column is provided with a medium outlet. The driving unit comprises a rotary driving system and a lateral load simulation system. The lateral load simulation system is used for simulating the lateral or radial load applied by the soft steel arm to the stand column. The rotary driving system comprises a rotatable base and a rotary control motor built in the base. The monitoring unit is used for capturing the deflection distribution of the stand column and the evolution law of the stress concentration area under the simulated relative swing condition of the soft steel arm and the stand column. The application can accurately set and adjust the angle, speed and phase of the thruster relative to the rotation of the stand column.

Description

Technical Field

[0001] This invention belongs to the field of marine oil and gas equipment testing technology, specifically relating to a prototype testing device and testing method for an ultra-large diameter liquid slip ring. Background Technology

[0002] In offshore oil extraction systems, subsea wellheads transport extracted oil and natural gas to Floating Production Storage and Offloading (FPSO) units via manifolds for processing. Due to the weathervane effect, the FPSO rotates around its mooring point under the influence of wind, waves, and currents. In extreme sea conditions, the FPSO's six-degree-of-freedom motion is transmitted through the york arms, causing significant dynamic elastic deformation (bending, torsion, etc.) in the support column structure of the hydraulic slip ring. However, existing design verification and prototype testing of ultra-large diameter hydraulic slip rings for SCM systems focus on assessing conventional loads such as internal pressure and rotational torque. Systematic experimental research and sufficient verification are lacking regarding the specific impact mechanism of the coupled motion of the FPSO and mooring system under the weathervane effect on the lateral deformation of a single column and the sealing performance of the hydraulic slip ring.

[0003] Therefore, this test outline focuses on the prototype of the ultra-large diameter liquid slip ring of the SCM system, and designs and implements a special test plan to simulate and evaluate the actual impact of the key load condition of "deformation of the column caused by the action of the soft steel arm" on the performance reliability of the liquid slip ring. Summary of the Invention

[0004] To address the technical problems existing in the background art mentioned above, this invention proposes a prototype test device and test method for ultra-large diameter liquid slip rings, which aims to solve the technical defects of traditional tests, such as the distortion of working condition simulation and insufficient verification of structural deformation resistance caused by ignoring the coupled deformation load of the soft steel arm-column.

[0005] To solve the above-mentioned technical problems, the present invention provides a prototype testing device for ultra-large diameter liquid slip rings, which includes an experimental unit, a monitoring unit, and a driving unit;

[0006] The experimental unit includes a pressure plate, an ear plate, a column, and a liquid slip ring;

[0007] The top of the column is equipped with the hydraulic slip ring; a pressure plate is fixedly mounted on the axial upper end face of the hydraulic slip ring; the hydraulic slip ring includes an outer ring and an inner ring; the outer ring has an upper medium channel and a lower medium channel inside, and the ear plate is fixedly mounted on the outer circumferential wall and connected to the drive unit through the ear plate; the outer ring also has a medium inlet, and the inner surface of the column has a medium outlet; the medium inlet has two holes, one above the other, which are respectively connected to the upper medium channel and the other to the lower medium channel; the upper medium channel and the lower medium channel are separated by a sealing groove; the inner ring is rigidly connected to the column; the medium outlet connects the inner ring and the column;

[0008] The drive unit includes a rotary drive system and a lateral load simulation system; the lateral load simulation system is used to simulate the lateral or radial load applied to the column by the soft steel arm; the rotary drive system includes a rotatable base and a rotary control motor built into the base; the base is rigidly connected to the bottom end of the column; the power output end of the rotary control motor is connected to the base to drive the base to rotate and drive the column and the inner ring as a whole to rotate bidirectionally at low speed in the horizontal plane;

[0009] The monitoring unit is used to capture in real time the deflection distribution and stress concentration zone evolution of the column under simulated relative swinging conditions between the soft steel arm and the column.

[0010] As a preferred embodiment of the present invention: both the outer ring and the inner ring are made of duplex stainless steel; a lower pressure plate is welded onto the column, and the inner ring is fixed to the lower pressure plate by bolts.

[0011] As a preferred embodiment of the present invention: the outer ring is configured with multiple axial main seals, leakage detection holes and radial dust seals; the axial main seal is the axial seal between the outer ring and the inner ring; the leakage detection holes are used to monitor whether the seal has failed; the radial dust seal is the radial dust seal between the outer ring and the inner ring, used to prevent external impurities from entering; the outer ring and the inner ring are supported by axial or radial bearings to form a redundant sealing system, while reserving displacement and strain monitoring interfaces to adapt to marine equipment operating condition verification.

[0012] As a preferred embodiment of the present invention: the test device further includes a sealing system installed between the outer ring and the inner ring; the sealing system adopts a double main seal, namely an axial main seal and a radial dustproof seal, symmetrically arranged on both sides of each medium channel inside the outer ring, and a leakage detection hole is provided on its outer side; at the same time, an isolation main seal, namely a sealing groove, is provided between adjacent medium channels to block potential medium cross leakage paths; the leakage detection hole is connected to the upper medium channel and the lower medium channel and is used to detect the sealing status.

[0013] As a preferred embodiment of the present invention: the lateral load simulation system includes a slide rail mounting bracket, an arc-shaped slide rail of ±60° mounted on the slide rail mounting bracket, a thruster slidably mounted on the arc-shaped slide rail, and a torque arm fixedly mounted on one side of the top of the slide rail mounting bracket;

[0014] The slide rail mounting bracket is fixed to one side of the base with the rotation axis of the column as the center;

[0015] One end of the torque arm is fixedly connected to one side of the top of the slide rail mounting bracket, and the other end is hinged to the ear plate via a pin.

[0016] The thruster moves independently along the arc-shaped slide rail, and its force-applying end always acts on a specific loading point on the column.

[0017] The thruster employs a graded loading method to simulate the deformation behavior of the column under lateral thrust in extreme sea states.

[0018] As a preferred embodiment of the present invention: the monitoring unit consists of a non-contact full-field strain measurement system, a displacement gauge, and a resistive strain gauge sensing unit;

[0019] The non-contact full-field strain measurement system is arranged around the column for full-field strain and deformation measurement; the non-contact full-field strain measurement system and the resistive strain gauge sensing unit work together to monitor and construct a structural mechanical performance monitoring scheme for the column and the liquid slip ring, realizing strain monitoring that combines the whole and the local.

[0020] The displacement gauge is a YWC-A type displacement gauge and is matched and installed on the outer wall of one side of the outer ring of the liquid slip ring. It realizes high-precision displacement measurement by sensing the change in distance between the probe and the conductor being measured, and monitors the change in the gap of the liquid slip ring in real time.

[0021] A prototype testing method for ultra-large diameter liquid slip rings, based on the aforementioned prototype testing device for ultra-large diameter liquid slip rings, specifically includes the following steps:

[0022] 1) First, assemble all components of the experimental unit, hoist the liquid slip ring to the top of the column and fix it rigidly; install the torque arm and ear plate; install and calibrate the monitoring unit; start the external data acquisition system to verify the multi-channel synchronous acquisition function; connect the medium inlet and medium outlet on the outer ring to the external oil circuit and keep the hydraulic line unobstructed, and check the pipeline sealing.

[0023] 2) Inject test media into the lower and upper media channels of the liquid slip ring under three different operating conditions:

[0024] Operating condition ①: The upper medium channel is filled with the slip ring designed to test the pressure of the test medium, while the lower medium channel is emptied and pressure is maintained;

[0025] Operating Condition ②: The upper medium channel is emptied and pressure is maintained, while the lower medium channel is injected with the slip ring at the design pressure of the test medium.

[0026] Operating condition ③: Dual-channel simultaneous liquid injection slip ring design pressure test medium;

[0027] 3) During the static side thrust loading test and commissioning, independent repeated tests were conducted for the three working conditions in step 2) above;

[0028] 4) In the dynamic soft steel boom side thrust loading test, a motion simulation method was adopted: the rotary drive system drives the column and inner ring to rotate continuously at a set speed, while the thruster in the lateral load simulation system moves along the arc-shaped slide rail in the same speed and opposite direction as the rotary drive system, so as to accurately reproduce the dynamic relative oscillation between the soft steel boom and the column when the FPSO makes a "wind vane" turn around the mooring point in actual sea conditions.

[0029] 5) Compare the Abaqus simulation results to verify the deflection and stress distribution.

[0030] As a preferred embodiment of the present invention: In step 3), during the independent repeated tests of the three working conditions in step 2), the base remains fixed and the thruster position is locked; the overall structure of the column and the fluid slip ring is simulated using Abaqus finite element method to predict deformation and stress distribution; based on the Abaqus finite element simulation data, it is confirmed that the lateral load applied by the lateral load simulation system is optimal at 40kN, and the lateral load is applied in increments of 5kN up to 40kN, with each load level held for 10 minutes, while simultaneously monitoring the strain of the column structure and the full-field strain distribution collected by the non-contact full-field strain measurement system; to verify the performance under extreme working conditions, a dual-channel test medium is simultaneously injected at the design pressure, and a lateral load of 40kN is applied in combination, and the deformation resistance of the fluid slip ring is evaluated by monitoring the change in column deflection.

[0031] As a preferred embodiment of the present invention: the dynamic soft steel arm lateral thrust loading in step 4) is carried out separately for the three media configuration conditions in step 2). The base rotation speed is gradually increased from 0.05 rpm to 0.25 rpm, and the lateral load is increased in increments of 5 kN to 40 kN. The traction behavior of the soft steel arm is simulated by using a ±60° arc-shaped slide rail. The strain of the column structure and the strain data of the non-contact optical full-field strain are collected simultaneously by a non-contact full-field strain measurement system. Under extreme conditions, the pressure test medium is designed by injecting liquid slip rings through dual channels and a lateral load of 40 kN is applied in combination. The deformation resistance performance of the liquid slip rings and the deflection response of the column under extreme coupled loads are evaluated by the monitoring unit.

[0032] By adopting the above technical solution, the present invention has the following beneficial effects:

[0033] This invention provides a complete reliability verification basis for the engineering application of ultra-large diameter liquid slip rings in SCM systems by building a liquid slip ring prototype at a 1:3 scale. The core innovation lies in the decoupling and coordinated control of the rotational motion of the column and the sliding rail motion of the lateral thruster through a set of coordinated motion control systems.

[0034] This invention enables precise setting and adjustment of the thruster's rotation angle, speed, and phase relative to the column, thereby faithfully reproducing the complex relative motion trajectory and dynamic deformation loads of the soft steel arm-column in a real marine environment within the laboratory. This design overcomes the limitations of traditional test devices that can only apply static or unidirectional dynamic loads, achieving a comprehensive and realistic assessment of the performance of the liquid slip ring under multi-physics coupled conditions in the ocean.

[0035] The present invention also has the following advantages:

[0036] (1) A standardized template for a "complex motion-load" coupled test platform has been developed.

[0037] The architecture of the device (fixed outer ring, rotating inner ring and column, programmable lateral loading system) and the testing method of this invention have high versatility and scalability. By adjusting the slide rail curvature, load size and motion program, this platform can be adapted to test the performance of rotating connecting equipment of different sizes and in different application scenarios (such as offshore wind power and deep-water mooring) under complex motion. It is expected to develop into a standardized reliability testing platform in this field and promote the advancement of industry testing standards.

[0038] (2) A high-precision dynamic load reproduction method based on "load decoupling-motion coordination" was created.

[0039] Existing technologies for simulating dynamic loads mostly employ unidirectional rotation or fixed-angle loading, failing to accurately reproduce the complex relative motion between two objects in marine engineering (such as an FPSO and its support column). This invention, through the coordinated motion of an independently controlled rotating base and a circular arc-rail thruster, decouples and reassembles the rotation of the support column and the swing of the flexible steel arm in physical space. This method allows for arbitrary programming and reproduction of specific relative motion trajectories and load histories within the laboratory, achieving a qualitative leap in dynamic load simulation from "approximate" to "precise." Attached Figure Description

[0040] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0041] Figure 1 A schematic diagram of the overall structure of the prototype test device for an ultra-large diameter liquid slip ring;

[0042] Figure 2 This is a partial structural schematic diagram of the prototype test device for the ultra-large diameter liquid slip ring of the present invention;

[0043] Figure 3 This is a flowchart of the test procedure for the prototype test device of the ultra-large diameter liquid slip ring of the present invention;

[0044] Figure 4 This is a partial cross-sectional view of the sealing system involved in the prototype test device for the ultra-large diameter liquid slip ring of this invention.

[0045] In the diagram: 1-Upper pressure plate; 2-Outer ring; 3-Ear plate; 4-Leakage detection hole; 5-Column; 6-Flange; 7-Slide rail mounting bracket; 8-Medium inlet; 9-Inner ring; 10-Displacement gauge; 11-Medium outlet; 12-Torque arm; 13-Thruster; 14-Slide rail; 15-Base; 16-Medium channel (including upper and lower medium channels); 17-Lower pressure plate; 18-Five seals. Detailed Implementation

[0046] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0047] The present invention will be further explained below with reference to specific embodiments.

[0048] like Figure 1-4 As shown in the figure, this embodiment provides a prototype test device for an ultra-large diameter liquid slip ring, which includes an experimental unit, a monitoring unit, and a driving unit.

[0049] The experimental unit includes a pressure plate 1, an ear plate 3, a column 5, a liquid slip ring, and a sealing system.

[0050] The bottom end of the column 5 is welded with a flange 6 and is rigidly connected to the base 15 by fasteners.

[0051] The fluid slip ring is fitted onto the top of the column 5, and a pressure plate 1 is fixedly mounted on its axial upper end face. The fluid slip ring includes an outer ring 2 and an inner ring 9. The outer ring 2 adopts a dual-channel design (i.e., the fluid slip ring has two independent fluid channels inside, corresponding to the upper and lower medium channels respectively, which can simultaneously or separately introduce different media to simulate the dual-path delivery requirements in actual working conditions). Its outer circumferential wall is fixed with an ear plate 3 and connected to the drive unit (specifically, the torque arm 12 in the hinged lateral load simulation system is kept static). The medium outlet 11 is located on the inner surface of the column 5, and the medium inlet 8 is located on the outer ring 2. The medium inlet 8 has two holes, one above the other, which are connected to the upper medium channel and the other below the medium channel respectively. The upper medium channel and the lower medium channel are separated by a sealing ring. The medium outlet 11 connects the inner ring 9 and the column 5. The inner ring 9 and the column 5 are rigidly connected by bolts. Specifically, a lower pressure plate 17 is welded onto the column 5, and the inner ring 9 is fixed to the lower pressure plate 17 by bolts. The base 15 is suitable for testing large-scale or full-size liquid slip rings with a diameter smaller than the flange. Both the outer ring 2 and the inner ring 9 are made of duplex stainless steel. The outer ring 2 can be configured with multiple axial main seals (the axial seal between the outer ring 2 and the inner ring 9), a leakage detection hole 4 (used to monitor whether the seal has failed), and a radial dust seal (the radial dust seal between the outer ring 2 and the inner ring 9, used to prevent external impurities from entering). The outer ring 2 and the inner ring 9 are supported by axial or radial bearings to rotate, forming a redundant sealing system. At the same time, displacement and strain monitoring interfaces are reserved to adapt to marine equipment operating condition verification.

[0052] The sealing system is installed between the outer ring 2 and the inner ring 9. It employs a dual main seal configuration—an axial main seal and a radial dust seal—symmetrically arranged on both sides of each medium channel (divided into a lower medium channel connecting the medium inlet 8 and an upper medium channel connecting the medium outlet 11) located inside the outer ring 2. A leak detection port 4 is provided on the outer side to prevent medium leakage and cross-contamination. Simultaneously, an isolation main seal is added between adjacent medium channels (five seals 18 are arranged from top to bottom, where the first and second main seals act on the upper medium channel, the fourth and fifth main seals act on the lower medium channel, and the third main seal is the isolation main seal) to block potential cross-leakage paths. The leak detection port 4 communicates with the sealing cavity (i.e., the sealed space between the inner and outer rings, i.e., the upper and lower medium channels) to detect the sealing status. The medium inlet 8 and the medium outlet 11 are respectively connected to the upper and lower medium channels.

[0053] The drive unit includes a rotary drive system and a lateral load simulation system.

[0054] The rotary drive system is used to drive the column 5 and the inner ring 9 rigidly connected to it to rotate bidirectionally at low speed (0-0.25 rpm) in the horizontal plane. It includes a rotatable base 15 and a rotary control motor built into the base 15. The base 15 is rigidly connected to the bottom end of the column 5, specifically to a flange 51 welded to the bottom end of the column 5. The power output end of the rotary control motor is connected to the base 15 to drive the base 15 to rotate and drive the column 5 and the inner ring 9 to rotate bidirectionally at low speed in the horizontal plane.

[0055] The lateral load simulation system is used to simulate the lateral or radial loads applied to the column 5 by the soft steel arm. It includes a slide rail mounting bracket 7, a ±60° arc-shaped slide rail 14 mounted on the slide rail mounting bracket 7, a thruster 13 slidably mounted on the arc-shaped slide rail 14, and a torque arm 12 fixedly mounted on one side of the top of the slide rail mounting bracket 7. The lateral load simulation system achieves dynamic loading by moving the thruster 13 along the arc-shaped slide rail 14. The slide rail mounting bracket 7 is fixed to one side of the base 15 with the rotation axis of the column 5 as its center. One end of the torque arm 12 is fixedly connected to one side of the top of the slide rail mounting bracket 7, and the other end is hinged to the ear plate 3 provided on the outer wall of the outer ring 2 via a pin. The thruster 13 can move independently along the arc-shaped slide rail 14, and its force-applying end always acts on a specific loading point on the column 5. The thruster 13 adopts a graded loading method to simulate the deformation behavior of the column 5 under lateral thrust in extreme sea states. The thruster 13 is integrated on the arc-shaped slide rail 14 with a stroke range of ±60° to reproduce the traction effect of the soft rigid arm system on the FPSO under the multi-field coupling of wind, waves and current, and then systematically study the mechanical response characteristics of the liquid slip ring under complex stress conditions.

[0056] The monitoring unit consists of a non-contact full-field strain measurement system, a displacement gauge 10, and a resistive strain gauge sensing unit. It captures in real-time the deflection distribution and stress concentration zone evolution of column 5 under the simulated relative oscillation condition of a soft steel arm (simulated by the motion of the thruster 13 and slide rail 14, simulating the traction effect of a soft rigid arm on the column in a real object) and column 5. The non-contact full-field strain measurement system is arranged around column 5 for full-field strain and deformation measurement; the resistive strain gauge is attached to the column surface for local strain monitoring. The non-contact full-field strain measurement system and the resistive strain gauge sensing unit work together to construct a monitoring scheme for the mechanical properties of column 5 and the liquid slip ring structure, achieving integrated overall and local strain monitoring. The displacement gauge 10 is a YWC-A type displacement gauge, matched and installed on the outer wall of the outer ring 2 of the liquid slip ring. It achieves high-precision displacement measurement by sensing the change in distance between the probe and the conductor being measured, and monitors the change in the liquid slip ring gap in real time.

[0057] This invention discloses a prototype testing method for an ultra-large diameter liquid slip ring, involving dynamic soft rigid arm side thrust loading tests. Before the formal testing, static side thrust loading tests are used as preparatory adjustments. The dynamic soft rigid arm side thrust loading test simultaneously acquires structural strain and non-contact full-field strain optical measurement data for multi-physics field cross-validation, aiming to accurately characterize and analyze the overall flexural deformation behavior of column 5 under complex loads. The test procedure mainly includes the following steps:

[0058] S100. First, assemble all components of the experimental unit. Hoist the liquid slip ring to the top of the column 5 and rigidly fix it with flange bolts (the lower pressure plate is welded to the outer surface of the column, and the inner ring of the liquid slip ring sits on this lower pressure plate and is fixed to the lower pressure plate with bolts). Install the torque arm 12 and ensure that the pin is tightly engaged with the ear plate 3 on the outer ring 2. Install and calibrate the monitoring equipment such as the non-contact full-field strain measurement system, displacement gauge 10, and resistive strain gauge sensing unit. Start the external data acquisition system to realize the multi-channel synchronous acquisition function. This data acquisition system is connected to all sensors (resistive strain gauge sensing unit, displacement gauge 10, pressure sensor, etc.) to realize multi-channel synchronous acquisition. Connect the medium inlet 8 and medium outlet 11 on the outer ring 2 to the external oil circuit and keep the hydraulic pipeline unobstructed. Check the pipeline sealing.

[0059] S200, inject test medium into the liquid slip ring sealing cavity, namely the lower medium channel and the upper medium channel, under three working conditions:

[0060] Operating condition ①: The upper medium channel is filled with the slip ring designed to test the pressure of the test medium, while the lower medium channel is emptied and pressure is maintained;

[0061] Operating Condition ②: The upper medium channel is emptied and pressure is maintained, while the lower medium channel is injected with the slip ring at the design pressure of the test medium.

[0062] Operating Condition ③: Dual-channel simultaneous liquid injection slip ring design pressure test medium.

[0063] S300. In the static lateral thrust loading test debugging, independent repeated tests were conducted for the three medium configuration conditions in step S200 above. During the test, the base 15 remained fixed, and the thruster 13 was locked in position. Through the results of Abaqus finite element simulation (finite element simulation of the overall structure of column 5-liquid slip ring, used to predict deformation and stress distribution), it was confirmed that the lateral load applied by the lateral load simulation system was optimal at 40kN. The lateral load was applied in increments of 5kN up to 40kN, with each load level held for 10 minutes. The strain of column 5 structure and the full-field strain distribution collected by the non-contact full-field strain measurement system were monitored simultaneously. To verify the performance under extreme conditions, the test medium at the design pressure was injected into the upper and lower medium channels simultaneously, and a lateral load of 40kN was applied jointly. The deformation resistance of the liquid slip ring was evaluated by monitoring the deflection change of column 5.

[0064] In the dynamic soft steel boom lateral thrust loading test (S400), a motion simulation method was employed: the rotary drive system continuously rotates the column 5 and inner ring 9 at a set speed (0.05–0.25 rpm), while the thruster 13 in the lateral load simulation system reciprocates along the arc-shaped slide rail 14 at the same speed but in the opposite direction to the rotary drive system. This accurately reproduces the dynamic relative oscillation between the soft steel boom and the column 5 during the "weathervane-like" turn of the FPSO around the mooring point in actual sea conditions. This design focuses on achieving a realistic simulation of the coupled deformation load of the soft steel boom and column 5. By applying lateral loads during relative motion, the interaction mechanism between the two in actual working conditions is effectively restored. The test was conducted for the three media configuration conditions in step S200. The rotational speed of the base 15 was gradually increased from 0.05 rpm to 0.25 rpm, and the lateral load was increased in increments of 5 kN to 40 kN. The ±60° arc-shaped slide rail 14 was used to simulate the traction behavior of the soft steel boom. The strain of column 5 and the strain data of non-contact optical full-field strain were simultaneously acquired by a non-contact full-field strain measurement system. Under extreme working conditions, the design pressure test medium of the slip ring was injected through the upper and lower medium channels and a 40kN lateral load was applied. The deformation resistance and column deflection response of the liquid slip ring under extreme coupled load were evaluated by a monitoring system (i.e., a monitoring system composed of a non-contact full-field strain measurement system, displacement gauge 10 and a resistive strain gauge sensing unit).

[0065] S500, compared with Abaqus simulation results, to verify the deflection and stress distribution.

[0066] The following specific implementation examples illustrate in detail the process of static side thrust loading debugging and dynamic soft rigid arm side thrust loading test of the present invention:

[0067] First, a heavy-duty crane is used to lift the liquid slip ring to be tested onto the top of column 5 of the special test platform; the liquid slip ring is then rigidly connected and fixed to column 5 using bolts on the flange to ensure a firm and reliable connection.

[0068] Next, install and adjust the torque arm 12. Precisely insert the pin of the torque arm 12 into the corresponding lug 3 of the outer ring 2 to ensure that the two are tightly engaged; at the same time, adjust the connection between the inner ring end of the torque arm 12 and the base 15 to ensure that the fluid slip ring has the necessary rotational freedom during the test.

[0069] Furthermore, a lateral load simulation system is installed on the lower side of column 5; the direction of force application of the lateral load simulation system should be strictly perpendicular to the axial direction of column 5; after installation, the pipeline connection status of its hydraulic system is carefully checked to ensure that there are no leaks and the connection is correct.

[0070] Furthermore, before the test begins, all key sensors (water pressure sensors installed on the media inlet 8 and media outlet 11 pipelines, torque sensors installed on the torque arm 12, displacement gauges 10 installed on the outside of the outer ring 2, and resistive strain gauge sensing units attached to key positions of the column 5 and the liquid slip ring) are calibrated: the water pressure sensors are calibrated to ensure accurate pressure measurement; the torque sensors are calibrated to ensure accurate torque measurement; the non-contact full-field strain measurement system is calibrated for subsequent strain and deflection measurements; and the displacement gauges 10 are calibrated for monitoring the sealing gap.

[0071] Further, after sensor calibration, installation is carried out, with displacement gauge 10 installed in the preset position for real-time monitoring of sealing gap changes in key parts of the liquid slip ring. A non-contact full-field strain measurement system is set up and debugged to effectively capture and measure the full-field strain and deflection distribution of the key structure of the liquid slip ring under load. The peripheral data acquisition system based on the LabVIEW / PXI protocol is started and debugged, focusing on verifying the normal synchronous acquisition function of all sensor channels (including pressure, torque, displacement, strain, etc.) and confirming that the sampling frequency is set and operating correctly.

[0072] Furthermore, to simulate the actual working medium pressure environment of the liquid slip ring, the following three typical operating conditions were set:

[0073] Operating condition ①: Inject the test medium at the design pressure of the slip ring into the upper channel cavity of the slip ring, while keeping the lower channel cavity emptied;

[0074] Operating condition ②: Inject the test medium designed for the slip ring into the lower channel cavity of the slip ring, while keeping the upper channel cavity emptied;

[0075] Operating condition ③: Simultaneously inject the test medium designed for the slip ring into the upper and lower channel cavities;

[0076] Each working condition requires an independent subsequent lateral thrust loading test.

[0077] First, conduct static side thrust loading tests for debugging:

[0078] Furthermore, the operator sets the loading program on the lateral load simulation system already installed on the underside of column 5. During the test, base 15 remains fixed, thruster 13 is locked in position, and lateral thrust is applied in increments of 5 kN, eventually reaching 40 kN. After each lateral load level (e.g., 5 kN, 10 kN, 15 kN, 20 kN) is reached, the pressure is maintained for at least 10 minutes. Simultaneously, the design pressure static pressure condition needs to be coupled to simulate the situation where pressure and lateral thrust coexist in actual working conditions.

[0079] Furthermore, the deflection deformation of column 5 under lateral thrust was measured using a non-contact full-field strain measurement system and a resistive strain gauge sensing unit.

[0080] Furthermore, after the test, the technicians integrated the data from all acquisition channels (including lateral thrust, pressure, torque, displacement, strain, deflection, etc.) and performed signal processing and time series alignment.

[0081] Furthermore, the measured column deflection data and key point strain data from the experiment were quantitatively compared with the simulation results of the pre-established finite element analysis model. The focus was on verifying the accuracy of the column deflection distribution shape and amplitude predicted by the Abaqus finite element model. The stress distribution predicted by the Abaqus finite element model was compared and analyzed with the strain gauge measured data to evaluate the reliability of the Abaqus finite element model and its ability to predict the deformation of the liquid slip ring mounting base.

[0082] Then, a dynamic soft steel arm side thrust loading test was conducted:

[0083] This test combines dynamic lateral thrust, rotational torque, and medium pressure to simulate the drift and rotational motion of an FPSO under extreme sea conditions, transmitted through a soft steel arm. This causes the column 5 to undergo simultaneous dynamic bending and torsional deformation. During this complex process, the structural integrity of the fluid slip ring under dual-channel asymmetric pressure is comprehensively verified. For the three medium configurations, the following test procedures must be performed independently and repeatedly:

[0084] Furthermore, after pressurization and stabilization at the design pressure, a dynamic coupling test was initiated, simultaneously activating the rotary drive system and the lateral load simulation system: the rotary drive system propelled the column 5 and inner ring 9 from rest to 0.25 rpm in increments of 0.05 rpm, while the lateral load was applied in increments of 5 kN to 40 kN; during this coordinated loading process, the thruster 13 in the lateral load simulation system moved independently along a fixed ±60° arc-shaped slide rail with an angular velocity opposite to and equal in magnitude to the rotation direction of the column 5. This "reverse constant velocity" motion control strategy ensured a continuous change in the velocity between the thruster 13 (simulating the end point of the soft steel arm) and the rotating column 5. The relative orientation of the FPSO is determined, thereby applying a lateral force with a periodically changing direction to column 5. This faithfully reproduces the dynamic swinging traction effect of the soft steel boom on the FPSO as it rotates around column 5 in actual sea conditions. Each lateral force loading process is controlled within 1-2 minutes to simulate the gradual characteristics of wave forces. The loading is completed and the design pressure is maintained (holding the load for no less than 2 minutes). Considering the intermittent motion characteristics of the actual FPSO, column 5 is synchronously driven to perform a standard reciprocating motion cycle of "120° forward rotation → pause for 30 seconds → 120° reverse rotation → pause for 30 seconds". Each load level is completed 3-5 cycles to evaluate the performance of the fluid slip ring under the combined action of alternating bending load and reciprocating rotation. When the lateral load reaches 40°... When the maximum kN is reached and the base speed reaches the maximum value of 0.25 rpm, the system enters the extreme durability test stage. The maximum lateral load and the maximum speed are maintained for no less than 30 minutes. At the same time, the column 5 continuously performs the above standard angle cycle for no less than 20 times to fully simulate and verify the durability and functional reliability of the liquid slip ring under continuous coupled motion and load environment in extreme sea conditions.

[0085] Furthermore, throughout the entire dynamic soft steel arm lateral thrust loading test, the data acquisition system must synchronously monitor and record the column deflection, strain distribution, and stress concentration data obtained by the non-contact full-field strain measurement system and the resistive strain gauge sensing unit. After the test, the lateral thrust must be removed first, then rotation must be stopped, and finally the internal pressure must be removed, followed by a preliminary inspection of the equipment.

[0086] Furthermore, the measured column deflection and strain data were compared with the Abaqus finite element simulation results to verify and correct the model.

[0087] Furthermore, by jointly loading and reproducing the effects of the coupled motion of the FPSO and mooring system and the lateral deformation of the single column 5, the three major load sources of dynamic lateral thrust, continuous rotational motion and dual-channel asymmetric pressure are coupled to construct a comprehensive test scheme that is closest to the actual marine operation conditions. This greatly improves the fidelity of the test and the difficulty of the assessment, and can provide highly convincing data support for the final reliability assessment of the liquid slip ring.

[0088] Thus, through two specific implementation examples, this invention clarifies the basic operating method of the prototype test system for ultra-large diameter liquid slip rings with single-point mooring, providing experimental reference for engineering operations in this field and filling the gap in experimental technology in this field.

[0089] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A prototype testing device for ultra-large diameter liquid slip rings, characterized in that: The experimental device includes an experimental unit, a monitoring unit, and a driving unit; The experimental unit includes a pressure plate (1), an ear plate (3), a column (5), and a liquid slip ring; The top of the column (5) is equipped with the liquid lubricating ring; the upper axial end face of the liquid lubricating ring is fixed with a pressure plate (1); the liquid lubricating ring includes an outer ring (2) and an inner ring (9); the outer ring (2) is provided with an upper medium channel and a lower medium channel inside, and the ear plate (3) is fixed on the outer circumference and connected to the drive unit through the ear plate (3); at the same time, the outer ring (2) is also provided with a medium inlet (8), and the inner surface of the column (5) is provided with a medium outlet (11); the medium inlet (8) has two holes, one above the other, and is connected to the upper medium channel and the lower medium channel respectively; the upper medium channel and the lower medium channel are separated by a sealing groove; the inner ring (9) is rigidly connected to the column (5); the medium outlet (11) is connected to the inner ring (9) and the column (5). The drive unit includes a rotary drive system and a lateral load simulation system; the lateral load simulation system is used to simulate the soft steel arm applying lateral or radial loads to the column (5); the rotary drive system includes a rotatable base (15) and a rotary control motor built into the base (15); the base (15) is rigidly connected to the bottom end of the column (5); the power output end of the rotary control motor is connected to the base (15) to drive the base (15) to rotate and drive the column (5) and the inner ring (9) to rotate bidirectionally at low speed in the horizontal plane; The monitoring unit is used to capture in real time the deflection distribution and stress concentration zone evolution of the column (5) under the simulated relative swinging condition between the soft steel arm and the column (5).

2. The prototype testing device for ultra-large diameter liquid slip rings as described in claim 1, characterized in that: The outer ring (2) and the inner ring (9) are both made of duplex stainless steel. A lower pressure plate (17) is welded onto the column (5), and the inner ring (9) is fixed onto the lower pressure plate (17) by bolts.

3. The prototype testing device for ultra-large diameter liquid slip ring as described in claim 1, characterized in that: The outer ring (2) is equipped with multiple axial main seals, leakage detection holes (4) and radial dust seals; the axial main seal is the seal between the outer ring (2) and the inner ring (9) in the axial direction; the leakage detection holes (4) are used to monitor whether the seal has failed; the radial dust seal is the dust seal between the outer ring (2) and the inner ring (9) in the radial direction, used to prevent external impurities from entering; The outer ring (2) and the inner ring (9) are supported by axial or radial bearings to form a redundant sealing system, while reserving displacement and strain monitoring interfaces to adapt to marine equipment operating condition verification.

4. The prototype testing device for ultra-large diameter liquid slip rings as described in claim 1, characterized in that: The test apparatus also includes a sealing system installed between the outer ring (2) and the inner ring (9); the sealing system adopts a double main seal, namely an axial main seal and a radial dust seal, symmetrically arranged on both sides of each medium channel inside the outer ring (2), and a leakage detection hole (4) is provided on its outer side; at the same time, an isolation main seal, namely a sealing groove, is provided between adjacent medium channels to block potential medium cross leakage paths; the leakage detection hole (4) is connected to the upper medium channel and the lower medium channel and is used to detect the sealing status.

5. The prototype testing device for ultra-large diameter liquid slip rings as described in claim 1, characterized in that: The lateral load simulation system includes a slide rail mounting bracket (7), an arc-shaped slide rail (14) of ±60° mounted on the slide rail mounting bracket (7), a thruster (13) slidably mounted on the arc-shaped slide rail (14), and a torque arm (12) fixedly mounted on one side of the top of the slide rail mounting bracket (7). The slide rail mounting bracket (7) is fixed to one side of the base (15) with the rotation axis of the column (5) as the center; One end of the torque arm (12) is fixedly connected to the top side of the slide rail mounting bracket (7), and the other end is hinged to the ear plate (3) by a pin. The thruster (13) moves independently along the arc-shaped slide rail (14), and its force-applying end always acts on a specific loading point on the column (5); The thruster (13) adopts a graded loading method to simulate the deformation behavior of the column (5) under the action of lateral thrust in extreme sea conditions.

6. The prototype testing device for ultra-large diameter liquid slip rings as described in claim 1, characterized in that: The monitoring unit consists of a non-contact full-field strain measurement system, a displacement gauge (10), and a resistive strain gauge sensing unit; The non-contact full-field strain measurement system is arranged around the column (5) for full-field strain and deformation measurement; the non-contact full-field strain measurement system and the resistive strain gauge sensing unit work together to monitor and construct a structural mechanical performance monitoring scheme for the column (5) and the liquid slip ring, so as to realize the overall and local strain monitoring. The displacement gauge (10) is a YWC-A type displacement gauge and is matched and installed on the outer wall of the outer ring (2) of the liquid slip ring. It realizes high-precision displacement measurement by sensing the change in distance between the probe and the conductor being measured, and monitors the change in the gap of the liquid slip ring in real time.

7. A method for testing ultra-large diameter liquid slip ring prototypes, based on the ultra-large diameter liquid slip ring prototype testing apparatus according to any one of claims 1 to 6, characterized in that, Specifically, the following steps are included: 1) First, assemble all the components of the experimental unit, hoist the liquid slip ring to the top of the column (5) and fix it rigidly; install the torque arm (12) and the ear plate (3); install and calibrate the monitoring unit; start the external data acquisition system to verify the multi-channel synchronous acquisition function; connect the medium inlet (8) and medium outlet (11) on the outer ring (2) to the external oil circuit and keep the hydraulic pipeline unobstructed, and check the pipeline sealing. 2) Inject test media into the lower and upper media channels of the liquid slip ring under three different operating conditions: Operating condition ①: The upper medium channel is filled with the slip ring designed to test the pressure of the test medium, while the lower medium channel is emptied and pressure is maintained; Operating Condition ②: The upper medium channel is emptied and pressure is maintained, while the lower medium channel is injected with the slip ring at the design pressure of the test medium. Operating condition ③: Dual-channel simultaneous liquid injection slip ring design pressure test medium; 3) During the static side thrust loading test and commissioning, independent repeated tests were conducted for the three working conditions in step 2) above; 4) In the dynamic soft steel arm side thrust loading test, a motion simulation method was adopted: the rotary drive system drives the column (5) and inner ring (9) to rotate continuously at a set speed. At the same time, the thruster (13) in the lateral load simulation system moves along the arc-shaped slide rail (14) in the same speed and opposite direction to the rotary drive system. This accurately reproduces the dynamic relative swing between the soft steel arm and the column (5) when the FPSO makes a "wind vane" turn around the mooring point in the actual sea state. 5) Compare the Abaqus simulation results to verify the deflection and stress distribution.

8. The prototype testing method for ultra-large diameter liquid slip rings as described in claim 7, characterized in that: In step 3), during the independent repeated tests of the three working conditions in step 2), the base (15) is kept fixed and the position of the thruster (13) is locked. The overall structure of the column (5) and the liquid slip ring is simulated by Abaqus finite element method to predict deformation and stress distribution. Through the results of the Abaqus finite element simulation, it is confirmed that the lateral load of the lateral load simulation system is 40kN, and the lateral load is applied in increments of 5kN to 40kN. Each load is held for 10 minutes, and the structural strain of the column (5) and the full-field strain distribution collected by the non-contact full-field strain measurement system are monitored simultaneously. In order to verify the performance under extreme working conditions, the test medium of the design pressure is injected into the dual channels at the same time, and a lateral load of 40kN is applied in combination. The deformation resistance of the liquid slip ring is evaluated by monitoring the deflection change of the column (5).

9. The prototype testing method for ultra-large diameter liquid slip rings as described in claim 7, characterized in that: The dynamic soft steel arm lateral thrust loading in step 4) is carried out for the three media configuration conditions in step 2). The base (15) rotation speed is gradually increased from 0.05 rpm to 0.25 rpm, and the lateral load is increased from 5 kN to 40 kN in each step. The traction behavior of the soft steel arm is simulated by using a ±60° arc-shaped slide rail (14). The structural strain of the column (5) and the non-contact optical full-field strain data are collected simultaneously by a non-contact full-field strain measurement system. Under extreme conditions, the pressure test medium is designed by injecting liquid slip rings through dual channels and a lateral load of 40 kN is applied in combination. The anti-deformation performance of the liquid slip rings and the deflection response of the column under extreme coupled loads are evaluated by the monitoring unit.

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