An experimental system simulating FLNG tail thruster
Through the experimental system of designing rotating parts, metal beams and wire ropes at the FLNG tail, the problem of low thrust magnitude and accuracy of simulated FLNG tail side thrust device in the pool experiment was solved, and the length of the wire rope was automatically adjusted to offset the influence of horizontal movement of the FLNG tail was realized. , improves experimental accuracy and reduces costs.
Patent Information
- Application Number
- CN202310310413.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-03-24
- Publication Date
- 2024-12-24
- Estimated Expiration
- 2043-03-24
AI Technical Summary
The existing simulated FLNG tail side thrust device has problems in the pool experiments that the thrust magnitude is difficult to ensure and the experimental accuracy is low, especially due to the complexity and high cost caused by the inability to accurately simulate the viscosity of the water body and the hull scale ratio.
An experimental system consisting of rotating parts, metal beams and wire ropes installed at the tail of the FLNG hull were designed. The metal beams passed through the ring track, and the length of the wire rope was automatically adjusted to offset the horizontal movement of the FLNG tail and reduced by the metal ring. The friction between the metal beam and the annular track ensures smooth sliding of the metal beam.
A side push device simulation experimental system with simple structure and easy operation is realized, which improves experimental accuracy and reduces costs. It can automatically adjust the length of the wire rope when the wave is incident to offset the impact of horizontal movement of the FLNG tail.
Smart Images
Figure CN116337404B_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of simulating floating body thrusters, and in particular to an experimental system simulating a FLNG tail thruster. Background Art
[0002] FLNG (Floating Liquefied Natural Gas, now commonly used as a synonym for the production storage and unloading device for producing floating liquefied natural gas) is a new type of device for the efficient development of deep-sea gas fields. In the actual operation process, FLNG needs to regularly export the liquefied natural gas stored in its liquid tank to free up tank capacity to maintain production. At present, there are two main ways to export FLNG, one of which is siding export, that is, during the export operation, FLNG and the shuttle LNGC (Liquefied Natural Gas Carrier) ship are arranged side by side, and the two are anchored by temporary mooring cables before export. Since the two ships are relatively close to each other, in order to avoid hull collision, the rear thruster is required to assist in adjusting the hull position during the berthing, export process and separation of the two ships. At present, FLNG ships that use siding export method are all equipped with thrusters at the rear.
[0003] Tank experiments are an important way to ensure the safety of FLNG operations. The simulation of FLNG export operations has also become a focus of attention in the marine engineering community in recent years. During the experiment, the simulation of the thruster system has the following difficulties:
[0004] (1) If the actual propeller is used for simulation, the thrust is difficult to guarantee because the water tank test mainly ensures the consistency of the Froude number, which leads to different Reynolds numbers (that is, the viscosity of the water body cannot be accurately simulated). In addition, the system is complex and expensive due to the limitation of the scale ratio of the hull.
[0005] (2) During actual operation, the thrust system will be at a fixed angle relative to the FLNG hull. Simple processing will cause the thrust force to change direction, affecting the experimental accuracy.
[0006] Therefore, the industry needs to propose a thruster simulation experiment system which has a simple structure, is easy to operate and can ensure experimental accuracy. Summary of the invention
[0007] In view of the deficiencies in the prior art, the present invention provides an experimental system for simulating a FLNG tail thruster.
[0008] The technical solution of the present invention to solve the above technical problems is as follows:
[0009] An experimental system simulating a FLNG stern thruster comprises a rotating member installed at the stern of the FLNG hull, wherein one end of the rotating member away from the FLNG hull is connected to a metal beam and a steel wire rope through a hinge joint, the rotating shaft of the metal beam is horizontally arranged, and the metal beam is made of a light material, and a weight is hung on one end of the steel wire rope away from the metal beam;
[0010] The experimental system further comprises an annular track, which is supported by a fixed bracket, and the metal beam passes through the annular track and slides in the annular track.
[0011] Through the above technical solution, the circular track is placed in the pool after being supported by a fixed bracket, the metal beam passes through the circular track, a heavy object is hung at the bottom end of the wire rope, the metal beam is vertical to the FLNG hull, and a side thrust is applied to the side of the metal beam away from the FLNG hull. When the FLNG is transferred sideways, due to the asymmetry caused by the side-by-side arrangement of the FLNG and the LNGC, when the wave is incident, the axis of the FLNG hull forms a certain angle with the wave incident direction, and on this basis, the bow roll motion is performed around a single point position. Considering the length of the FLNG hull, the horizontal motion range of its stern is relatively large. At this time, the metal beam will reciprocate relative to the circular track, and the length of the wire rope is automatically adjusted to offset the impact caused by the horizontal motion of the FLNG stern.
[0012] Furthermore, the system also includes a metal ring adapted to the annular track, the metal ring is located in the annular track, and the metal ring is slidably connected to the annular track, and the metal beam passes through the metal ring.
[0013] Through the above technical solution, the provision of the metal ring can reduce the friction between the metal beam and the annular track, making the sliding of the metal beam smoother.
[0014] Furthermore, the metal beam is provided with a groove along its length direction, the cross section of the groove is C-shaped, and the steel wire rope is located in the groove.
[0015] Furthermore, the rotating member includes a fixed rod and a rotating rod, the fixed rod is fixed to the rear of the FLNG hull, the rotating rod passes through the fixed rod, a fastening device is provided between the rotating rod and the fixed rod, and the hinged head is provided at the bottom end of the rotating rod.
[0016] Furthermore, the fixed bracket includes a support and a bracket, the support is located at the end of the annular track, the support is provided with a guide groove, and the guide groove is sleeved on the top end of the bracket.
[0017] Furthermore, the support is triangular, and the top end of the bracket is adapted to the support.
[0018] Furthermore, the system also includes a mounting cable, and the mounting cable is used to connect the top end of the bracket.
[0019] Furthermore, a positioning float is provided at one end of the installation cable away from the bracket.
[0020] Furthermore, one end of the metal beam away from the hinge joint is connected to a second positioning float.
[0021] In summary, compared with the prior art, the above technical solution has the following beneficial effects:
[0022] (1) The circular track is supported by a fixed bracket and placed in a pool. The metal beam passes through the circular track, and a heavy object is hung at the bottom of the wire rope. The metal beam is perpendicular to the FLNG hull. A side thrust is applied to the side of the metal beam away from the FLNG hull. When the FLNG is transported sideways, due to the asymmetry caused by the side-by-side arrangement of the FLNG and the LNGC, when waves are incident, the axis of the FLNG hull forms a certain angle with the wave incident direction, and on this basis, the FLNG bow rolls around a single point. Considering the length of the FLNG hull, the horizontal movement range of its stern is relatively large. At this time, the metal beam will reciprocate relative to the circular track, and the length of the wire rope is automatically adjusted to offset the impact caused by the horizontal movement of the FLNG stern.
[0023] (2) The setting of the metal ring can reduce the friction between the metal beam and the annular track, making the sliding of the metal beam smoother. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] Figure 1 This is a schematic diagram of the overall structure installed in place in an embodiment of the present invention;
[0025] Figure 2 A top view of an embodiment of the present invention;
[0026] Figure 3 It is a schematic diagram of an embodiment of the present invention under a stress state;
[0027] Figure 4 A schematic diagram of a structure prepared for installation in an embodiment of the present invention;
[0028] Figure 5 Schematic diagram of the installation of the circular track and weights according to the embodiment of the present invention;
[0029] Figure 6 It is a schematic diagram of the connection between the annular track and the bracket according to an embodiment of the present invention.
[0030] Explanation of the reference numerals in the accompanying drawings: 1. Fixed rod; 2. Rotating rod; 3. Hinge joint; 4. Metal beam; 5. Groove; 6. Metal ring; 7. Annular track; 8. Wire rope; 9. Hook; 10. Weight; 11. Bracket; 12. Support; 13. Positioning float 1; 14. Positioning float 2; 15. Installation cable. DETAILED DESCRIPTION
[0031] The principles and features of the present invention are described below in conjunction with all the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.
[0032] The embodiment of the present invention discloses an experimental system for simulating a FLNG tail thruster.
[0033] Reference Figure 1-Figure 6 , an experimental system simulating a FLNG stern thruster, comprising a rotating member installed at the stern of the FLNG hull, the rotating member comprising a fixed rod 1 and a rotating rod 2, the fixed rod 1 being fixedly arranged at the stern of the FLNG hull, the rotating rod 2 being connected to the fixed rod 1 by a fastening device, before the experiment is carried out, the rotating rod 2 will be twisted along its axis by a fixed angle relative to the fixed rod 1, and then the fastening device is locked to ensure that no relative torsional movement occurs between the rotating rod 2 and the fixed rod 1 during the experiment; the end of the rotating rod 2 away from the FLNG hull is rotatably connected to a metal beam 4 through a hinge 3, and the metal beam 4 is made of a lightweight material, the material used in the present invention is copper, the gravity on the metal beam 4 is equal to the buoyancy on it in the water, so as to ensure that the metal beam will not sink, the rotating shaft of the metal beam 4 is arranged horizontally, so that the metal beam swings under the action of the lateral thrust (wave); the hinge is fixedly connected to a steel wire rope 8; the end of the steel wire rope connected to the hinge is set as a fixed end, and the end of the steel wire rope not connected to the hinge is set as a free end. The metal beam 4 is provided with a groove 5 along its length, the cross section of the groove 5 is C-shaped and the opening faces downward, and the steel wire rope extends into the groove. A hook 9 is provided at the free end of the steel wire rope, and a weight is hung on the hook 9. The weight in the embodiment of the present invention is a weight 10;
[0034] The experimental system also includes a circular track 7, which is supported by a fixed bracket. The movable end of the metal beam 4 passes through the circular track 7 and slides in the circular track 7. The free end of the wire rope passes through the circular track. Under the action of the weight and the circular track, the free end of the wire rope bends and droops with the circular track as the bending point. Figure 1 shown.
[0035] Reference Figure 2 and Figure 3The circular track 7 is supported by a fixed bracket and placed in the pool. The metal beam 4 passes through the circular track 7. A weight 10 is hung at the bottom of the wire rope 8. The metal beam 4 is perpendicular to the length direction of the FLNG hull. A side thrust is applied to the side of the metal beam 4 away from the FLNG hull. When the FLNG is transported side by side, due to the asymmetry caused by the side-by-side arrangement of the FLNG and the LNGC, when the wave is incident, the axis of the FLNG hull forms a certain angle with the wave incident direction, and on this basis, the bow roll motion around a single point position is performed. Considering the length of the FLNG hull, the horizontal motion range of its stern is relatively large. At this time, the metal beam 4 will reciprocate relative to the circular track 7 in the circular track (swing in the circular track in the horizontal direction).
[0036] by Figure 2 and Figure 3 Take this as an example to illustrate:
[0037] The end of the metal beam connected to the hinge joint is set as the installation end of the metal beam, and the end of the metal beam away from the hinge joint is set as the movable end of the metal beam. When the metal beam is in the swinging process, the free end of the wire rope is bent at the circular track. Figure 2 The intersection of the metal beam and the circular track is the origin. At this time, the angle between the metal beam and the circular track is 90 degrees. When the hull is subjected to side thrust, the movable end of the metal beam is subjected to thrust, and the metal beam swings counterclockwise in the circular track with the hinge as the rotation axis. Then the angle between the movable end of the metal beam and the circular track (the angle in the upper right area) gradually decreases, and the wire rope is located in the groove with the circular track as the bending point. When the metal beam swings counterclockwise in the circular track, the wire rope swings synchronously with the metal beam and continues to bend with the circular track as the bending point. At this time, the depth of the free end of the wire rope in the pool changes (becomes shallower), that is, when the metal beam (the part of the wire rope in the groove) is perpendicular to the circular track, the depth of the wire rope in the pool is the largest. As the metal beam swings, the wire rope is driven to swing synchronously, so that the length of the wire rope in the pool is automatically adjusted, thereby offsetting the impact caused by the horizontal movement of the tail of the FLNG.
[0038] Under the condition of hull motion, it can be ensured that the thrust load at the stern is at a fixed angle to the hull, such as Figure 3 shown.
[0039] The system can be used not only for FLNG devices with single-point mooring positioning, but also for FLNG devices with multi-point mooring positioning.
[0040] Reference Figure 1 and Figure 6The system further includes a metal ring 6 adapted to the annular track 7, the metal ring 6 is located in the annular track 7, and the metal ring 6 is slidably connected to the annular track 7, and the metal beam 4 passes through the metal ring 6. The provision of the metal ring 6 can reduce the friction between the metal beam 4 and the annular track 7, so that the sliding of the metal beam 4 is smoother.
[0041] It should be noted that: when the metal ring is provided, the groove on the metal beam may be provided or not provided, and the present invention adopts the method of providing the groove.
[0042] The fixed bracket includes a support 12 and a bracket 11. The support 12 is located at the end of the annular track 7. The support 12 is triangular and has a guide groove. The top of the bracket 11 is triangular. The guide groove is sleeved on the support 12 to ensure the connection stability between the bracket 11 and the support 12.
[0043] The height of the bracket 11 can be adjusted according to the height of the hinge head 3 and the circular track 7 from the water pool, so that the height of the bracket 11 is consistent with the height of the hinge head 3 and the circular track 7 from the water pool, so that the lateral thrust exerted on the FLNG hull is basically equal to the weight of the weight 10 in water.
[0044] Reference Figure 1 and Figure 5 The system also includes an installation cable 15, which is used to connect the top of the bracket 11. A positioning float 13 is provided at one end of the installation cable 15 away from the bracket 11.
[0045] Reference Figure 5 One end of the metal beam 4 away from the hinge joint 3 is connected to a positioning float 14.
[0046] The specific installation method of the embodiment of the present invention is:
[0047] Step 1: First, install the rotating parts on the rear bottom plate of the FLNG hull model, and then complete the connection of the hinged joint, the metal beam with a C-shaped cross-section and the wire rope, and the second connection of the positioning float;
[0048] Secondly, connect the rotating rod and the fixed rod so that the metal beam is vertical to the FLNG hull. Then calculate the height of the bracket based on the draft of the FLNG under a given loading capacity, the height of the rotating rod and the fixed rod, and the vertical distance from the bottom of the pool to the water surface. After that, install two brackets at the bottom of the pool, install the support and installation cable on the top of the bracket, install the positioning buoy on the bracket, and finally launch the FLNG hull and complete the installation of the single-point mooring system.
[0049] Step 2: First, install the metal ring in the closed circular metal track so that it can slide freely along the circular track; then, with the cooperation of the auxiliary work boat, recover the positioning float 2 of the metal beam, remove the float, and pass the free end of the metal beam and the wire rope through the metal ring on the auxiliary work boat, then connect the hook to the free end of the wire rope, and finally select the weight according to the side thrust and hang it on the hook; finally, recover the installation cable and positioning float 1, remove the positioning float 1, and pass the installation cable through the top opening of the support, as shown in the figure. Figure 3 shown.
[0050] Step 3: The auxiliary work boat pulls the two installation cables. The circular track will gradually slide down along the two installation cables under the action of gravity until the guide groove and the top of the bracket are fully matched. Then the ends of the two installation cables are connected to the floating balls, and the auxiliary work boat sails away. Figure 5 shown.
[0051] Step 4: Complete the mooring connection between LNGC and FLNG.
[0052] Step 5: Start the pool experiment.
[0053] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims
1. An experimental system simulating a FLNG tail thruster, characterized in that: It comprises a rotating part installed at the rear of the FLNG hull, wherein the end of the rotating part away from the FLNG hull is connected to a metal beam (4) and a steel wire rope (8) through a hinge joint (3), the rotating shaft of the metal beam (4) is arranged horizontally, and the metal beam (4) is made of a light material, and a heavy object is suspended at the end of the steel wire rope (8) away from the metal beam (4); The experimental system further comprises an annular track (7), wherein the annular track (7) is supported by a fixed bracket, and the metal beam (4) passes through the annular track (7) and slides in the annular track (7); The metal beam is perpendicular to the length direction of the FLNG hull. When the FLNG is transported side by side, due to the asymmetry caused by the side-by-side arrangement of the FLNG and the LNGC, when the wave is incident, the axis of the FLNG hull forms a certain angle with the wave incident direction, and on this basis, the bow roll movement around a single point position is performed. At this time, the metal beam will reciprocate in the circular track relative to the circular track, and the length of the wire rope will be automatically adjusted to offset the impact caused by the horizontal movement of the tail of the FLNG; The specific installation method is: Step 1: First, install the rotating parts on the rear bottom plate of the FLNG hull model, and then complete the connection of the hinged joint, the metal beam with a C-shaped cross-section and the wire rope, and the second connection of the positioning float; Secondly, connect the rotating rod and the fixed rod to make the metal beam vertical to the FLNG hull. Then calculate the height of the bracket according to the draft of the FLNG under the given loading capacity, the height of the rotating rod and the fixed rod, and the vertical distance from the bottom of the pool to the water surface. Then install two brackets at the bottom of the pool, install the support and the installation cable on the top of the bracket, install the positioning buoy on the bracket, and finally launch the FLNG hull and complete the installation of the single-point mooring system. Step 2: First, install the metal ring in the closed circular metal track so that it can slide freely along the circular track; then, with the cooperation of the auxiliary work boat, recover the positioning float 2 of the metal beam, remove the float, and make the free end of the metal beam and the wire rope pass through the metal ring on the auxiliary work boat, then connect the hook to the free end of the wire rope, and finally select the weight according to the side thrust and hang it on the hook; finally, recover the installation cable and positioning float 1, remove the positioning float 1, and pass the installation cable through the top opening of the support; Step 3: The auxiliary work boat pulls the two installation cables, and the circular track will gradually slide down along the two installation cables under the action of gravity until the guide groove and the top of the bracket are fully matched, and then the ends of the two installation cables are connected to the floating balls, and the auxiliary work boat sails away; Step 4: Complete the mooring connection between LNGC and FLNG; Step 5: Start the pool experiment.
2. The experimental system for simulating a FLNG tail thruster according to claim 1, characterized in that: The system further comprises a metal ring (6) adapted to the annular track (7), the metal ring (6) being located inside the annular track (7), the metal ring (6) being slidably connected to the annular track (7), and the metal beam (4) passing through the metal ring (6).
3. The experimental system for simulating a FLNG tail thruster according to claim 1 or 2, characterized in that: The metal beam (4) is provided with a groove (5) along its length direction, the cross section of the groove (5) is C-shaped, and the steel wire rope (8) is located in the groove (5).
4. The experimental system for simulating a FLNG tail thruster according to claim 1, characterized in that: The rotating member comprises a fixed rod (1) and a rotating rod (2), wherein the fixed rod (1) is fixedly arranged at the rear of the FLNG hull, the rotating rod (2) is passed through the fixed rod (1), a fastening device is arranged between the rotating rod (2) and the fixed rod (1), and the hinged joint (3) is arranged at the bottom end of the rotating rod (2).
5. The experimental system for simulating a FLNG tail thruster according to claim 1, characterized in that: The fixed bracket comprises a support (12) and a bracket (11), wherein the support (12) is located at the end of the annular track (7), and the support (12) is provided with a guide groove, and the guide groove is sleeved on the top end of the bracket (11).
6. The experimental system for simulating a FLNG tail thruster according to claim 5, characterized in that: The support (12) is triangular in shape, and the top end of the bracket (11) is adapted to fit the support (12).
7. The experimental system for simulating a FLNG tail thruster according to claim 6, characterized in that: The system further comprises a mounting cable (15), wherein the mounting cable (15) is used to connect to the top end of the bracket.
8. The experimental system for simulating a FLNG tail thruster according to claim 7, characterized in that: A positioning float (13) is provided at one end of the installation cable (15) away from the bracket (11).
9. The experimental system for simulating a FLNG tail thruster according to claim 1, characterized in that: One end of the metal beam (4) away from the hinge joint (3) is connected to a second positioning float (14).