CN216185921U

CN216185921U - Equivalent simulation device for flow load of single-point mooring system in stormy wave environment

Info

Publication number: CN216185921U
Application number: CN202122300568.3U
Authority: CN
Inventors: 刘利琴; 孟春蕾; 刘亚柳; 郭颖; 黄郑鑫
Original assignee: Tianjin University
Current assignee: Tianjin University
Priority date: 2021-09-18
Filing date: 2021-09-18
Publication date: 2022-04-05
Anticipated expiration: 2031-09-18

Abstract

The utility model discloses an equivalent simulation device for flow load of a single-point mooring system in a stormy wave environment, which is characterized by comprising a pull rope, a fixed pulley block and a weight, wherein the fixed pulley block is arranged on a support frame, is arranged in the same vertical plane, is provided with a lower end pulley and an upper end pulley positioned above the lower end pulley, one end of the pull rope is connected with a connecting point arranged on a hull of an FPSO model, the connecting point is as high as the center of gravity of the FPSO model, the pull rope is horizontally led out from the connecting point along the flow load direction, and is led out of a force application end by winding the lower end pulley and the upper end pulley, and the weight is applied to the force application end of the pull rope. The utility model can simulate and forecast the motion and stress of the FPSO single point mooring system under the working sea condition more truly, can provide scientific basis for the design, construction and safe production operation of the FPSO and enrich the method for simulating the flow load in the pool test.

Description

Equivalent simulation device for flow load of single-point mooring system in stormy wave environment

Technical Field

The utility model relates to the technical field of single point mooring system model tests, in particular to an equivalent simulation device for flow load of a single point mooring system in a stormy wave environment.

Background

In recent years, the total amount of petroleum consumption in China is on the trend of increasing year by year, and land petroleum resources are not enough to meet our needs, so that exploration and production activities are gradually developing to deep sea areas farther offshore. Floating Production Storage and Offloading platform fpso (floating Production Storage and Offloading) is a comprehensive large-scale marine oil exploitation engineering equipment integrating oil and gas development, Production treatment, Storage and transportation and personnel residence. With the development of the resource strategy of countries in the world to deep sea, the FPSO has become the mainstream facility for ocean development nowadays. Depending on the sea conditions in different sea areas, the FPSO mainly uses mooring methods including spread mooring systems, dynamic positioning systems and single point mooring systems. The single point mooring system can automatically adjust the bow of the ship through a weathervane effect to align the direction of the wind waves, so that the influence of the wind waves on the ship body is reduced to the minimum, and therefore the mooring mode is most commonly applied.

In order to ensure that the FPSO can perform production operations on the sea for a long time, the newly designed FPSO generally needs to perform special model test research, particularly model tests under the action of wind, waves and currents under the conditions corresponding to the survival sea state and the operation sea state. The motion and stress of the model are measured in the test, so that the motion and stress of the FPSO entity under the marine environment condition are forecasted, and a scientific basis is provided for the design, construction and safe production operation of the FPSO. The simulation of wind stroke and wave in the test is realized by a special fan unit and a wave generator respectively, but the simulation of a real flow field is difficult to realize, and most ocean engineering pools are not provided with related facilities at present. In order to obtain a more accurate and reliable model test result, a convenient and reliable flow load simulation device is a key technology to be solved urgently by a pool scale ratio model test.

SUMMERY OF THE UTILITY MODEL

The utility model provides an equivalent simulation device for flow load of a single-point mooring system in a stormy wave environment for solving the technical problems in the prior art.

The technical scheme adopted by the utility model for solving the technical problems in the prior art is as follows: the equivalent simulation device comprises a pull rope, a fixed pulley block and weights, wherein the fixed pulley block is installed on a support frame and arranged in the same vertical plane, a lower end pulley and an upper portion pulley located above the lower end pulley are arranged, one end of the pull rope is connected with a connection point arranged on a hull of an FPSO model, the connection point is equal to the center of gravity of the FPSO model in height, the pull rope is horizontally led out from the connection point in the flow load direction and is wound around the lower end pulley and the upper portion pulley to lead out a force application end, and the weights are applied to the force application end of the pull rope.

When the load of the oncoming wave flow is simulated, the connecting point is transversely arranged on a hull tail sealing plate of the FPSO model in the middle, the support frame is fixedly connected to a trailer crossing the test water tank, and the fixed pulley block and the connecting point I are located in the same vertical plane.

When non-oncoming wave flow load is simulated, the connecting point is longitudinally and centrally arranged on a bulwark of the FPSO model, which is opposite to the flow load, and the supporting frame is fixedly connected to the side wall of the test pool.

The lower end pulley is connected to the support frame in a position-adjustable manner.

The support frame is equipped with the pole setting the upper end of pole setting is equipped with the cantilever bar, the upper portion pulley has two, and one is installed on the cantilever end of cantilever bar, and another is installed the upper end of pole setting, the lower extreme pulley is installed the lower tip of pole setting.

The utility model has the advantages and positive effects that: the flow load borne by the model is converted into the weight gravity convenient to operate by an equivalent conversion method, an idea is provided for an ocean engineering model test lacking a simulation flow field, and the method for simulating the flow load in the pool test is enriched. The motion and stress of the FPSO single point mooring system under the working sea condition can be simulated and predicted more truly, and scientific basis is provided for design, construction and safe production and operation of the FPSO.

Drawings

FIG. 1 is a side view of the present invention in use to simulate oncoming flow loading;

FIG. 2 is a top view of a non-oncoming flow load simulated using the present invention;

FIG. 3 is a side view of FIG. 2;

FIG. 4 is a schematic diagram of weight mass solution when the non-wave-incident flow load is simulated by applying the method of the utility model.

In the figure: 1. FPSO model; 1-1 inner rotating tower; 2. a connection point; 3. pulling a rope; 4. a fixed pulley block; 4-1, a lower end pulley; 4-2, an upper pulley; 5. a pool side wall; 6. a support frame; 6-1, erecting a rod; 6-2, cantilever bar; 7. a weight; 8. And (4) towing the trailer.

Detailed Description

In order to further understand the contents, features and effects of the present invention, the following embodiments are illustrated and described in detail with reference to the accompanying drawings:

referring to fig. 1 to 4, an equivalent simulation device for a flow load of a single-point mooring system in a wind and wave environment comprises a pull rope 3, a fixed pulley block 4 and weights 7, wherein the fixed pulley block 4 is mounted on a support frame 6, is arranged in the same vertical plane, and is provided with a lower end pulley 4-1 and an upper end pulley 4-2 positioned above the lower end pulley 4-1, one end of the pull rope 3 is connected with a connection point 2 arranged on a hull of an FPSO model 1, the connection point 2 is equal to the center of gravity of the FPSO model, the pull rope 3 is horizontally led out from the connection point 2 in the flow load direction, and is wound around the lower end pulley 4-1 and the upper end pulley 4-2 to lead out a force application end, and the weights 7 are applied to the force application end of the pull rope 3.

When the load of the oncoming wave flow is simulated, the connecting point 2 is transversely arranged on a hull tail sealing plate of the FPSO model 1 in the middle, the support frame 6 is fixedly connected to a trailer 8 crossing the test water tank, and the fixed pulley block 4 and the connecting point 2 are positioned in the same vertical plane.

When non-oncoming wave flow load is simulated, the connecting point 2 is longitudinally and centrally arranged on a bulwark of the FPSO model, which is opposite to the flow load, and the support frame 6 is fixedly connected on the side wall 5 of the test pool.

In this embodiment, the lower end pulley 4-1 is connected to the supporting frame 6 in a position-adjustable manner, so as to facilitate installation and adjustment. The more concrete structure does: the support frame 6 is provided with an upright rod 6-1, the upper end of the upright rod 6-1 is provided with a cantilever rod 6-2, the number of the upper pulleys 4-2 is two, one is arranged at the cantilever end of the cantilever rod 6-2, the other is arranged at the upper end part of the upright rod 6-1, and the lower pulley 4-1 is arranged at the lower end part of the upright rod 6-1, so that the structure is simple and the use is convenient.

The working principle of the utility model is as follows:

referring to fig. 1, when an oncoming flow load is simulated, the direction of the oncoming flow load, i.e., the flow load in the 180 ° direction, is fixed, and according to an empirical formula of the longitudinal flow load in the specifications of the "international navigation and current loads on VLCCs", i.e., the formula (1), the flow load under the model scale can be obtained by calculation, and then the flow load is equivalent to the weight mass, so that the calculation is simple.

In the formula, F_xFor longitudinal flow loading, C_x(θ) is the longitudinal flow force coefficient associated with the flow angle of attack, ρ is the fluid density, V_cThe flow rate, B the profile width and T the draft.

F_x＝mg

m＝F_x/g

Referring to fig. 2 to 4, when non-oncoming flow load is simulated, that is, the flow direction of the flow load is the other direction of the non-oncoming flow direction, according to the empirical formula in the above-mentioned OCIMF specification, that is, the formula (2), the flow yawing moment of the actual FPSO about the center of the inner tower at different flow attack angles can be calculated, and the yawing moment of the model FPSO is calculated by using the scaling ratio.

In the formula, M_zIs a hydrodynamic torque, C_z(theta) is the yaw coefficient associated with the angle of flow attack, ρ is the fluid density, V_cIs the flow rate, L_BPIs the length between vertical lines, and T is the draught.

Assuming that the center of the inner tower 1-1 in the FPSO model is fixed (actually, the center can move, but subsequent verification shows that the actual movement of the center of the inner tower 1-1 has little influence on the mass of the applied weight, and the influence is ignored within five percent), the pull rope 3 moves along with the pivoting rotation of the FPSO, and through the pulley block 4, the vertical distance from the center of the inner tower to the connecting line between the connecting point and the pulley block can be determined by the positions of the center of the inner tower 1-1 and the connecting point in the horizontal plane, namely, the force arm of the weight gravity about the center of the inner tower, so as to obtain the moment of the hydrodynamic force to be applied. Because the yawing moments of the FPSO model under different flow attack angles are different, and the moment arm of the weight gravity about the center of the inner tower 1-1 can also change after the FPSO model is yawing, on the basis of assuming that the center of the inner tower 1-1 is not changed, the weight mass required to be applied by the FPSO under different yawing angles is calculated according to the geometric relationship.

A connecting point is A, a fixed pulley block is B, the center of an inner rotating tower is C, a connecting point after rotation is D, and the gravity acceleration is g. Since the initial position is known, Δ ABC is trilateralized, and angle ACB can be found by the cosine theorem:

therefore:

∠BCD＝∠ACB+α (4)

wherein, the yawing angle alpha can be measured by adopting a six-degree-of-freedom motion instrument.

Perpendicular to BD side in Δ BCD, arm i:

the mass of the weight can be obtained by knowing the flow force moment:

although the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, the present invention is not limited to the above-described embodiments, which are merely illustrative and not restrictive, and those skilled in the art can make many modifications without departing from the spirit and scope of the present invention as defined in the appended claims.

Claims

1. The equivalent simulation device for the flow load of the single-point mooring system in the stormy wave environment is characterized by comprising a pull rope, a fixed pulley block and a weight, wherein the fixed pulley block is installed on a support frame and arranged in the same vertical plane, a lower end pulley and an upper pulley positioned above the lower end pulley are arranged, one end of the pull rope is connected with a connecting point arranged on a hull of an FPSO model, the connecting point is equal to the center of gravity of the FPSO model in height, the pull rope is horizontally led out from the connecting point along the flow load direction and is wound around the lower end pulley and the upper pulley to lead out a force application end, and the weight is applied to the force application end of the pull rope.

2. The equivalent simulation device for flow load of a single-point mooring system in a stormy wave environment as claimed in claim 1, wherein when simulating an oncoming flow load, the connection point is transversely and centrally arranged on a tail closure plate of a hull of the FPSO model, the support frame is fixedly connected to a trailer crossing a test pool, and the fixed pulley block and the connection point i are located in the same vertical plane.

3. The equivalent simulation device for the flow load of the single-point mooring system in the storm environment according to claim 1, wherein when the non-head-on wave flow load is simulated, the connection point is longitudinally and centrally arranged on a bulwark of the FPSO model, which is opposite to the flow load, and the support frame is fixedly connected to the side wall of the test pool.

4. The equivalent simulator of flow loading in a single point mooring system in a stormy wave environment of claim 1, wherein the lower end pulley is positionally adjustably attached to the support frame.

5. The equivalent simulation device of flow load of single point mooring system under storm environment of claim 1 wherein said support frame is provided with a vertical rod, a cantilever rod is provided at the upper end of said vertical rod, two of said upper pulleys are provided, one is mounted on the cantilever end of said cantilever rod, the other is mounted at the upper end of said vertical rod, and said lower pulley is mounted at the lower end of said vertical rod.