Device and method for tank model sloshing experiment

Abstract

The application discloses a device and method for liquid tank model sloshing experiment, which comprises a support system, a liquid tank displacement limiting system and an experimental liquid tank model. The support system is installed in a three-dimensional wave pool or an open water area, the experimental liquid tank model is installed on the support system through the liquid tank displacement limiting system, the motion of the experimental liquid tank model under different wave-approaching angles is decomposed into rolling, yawing and heaving motions through the liquid tank displacement limiting system, and the motion response of a marine structure such as a liquid-carrying ship to waves on the sea is simulated through wave making in the three-dimensional wave pool. The device has the advantages of reasonable design, simple structure, universality, convenience in installation and operation, and true restoration of the motion response of the liquid tank in waves.

Description

Technical Field

[0001] This invention relates to the field of experimental equipment for free sloshing of liquids, and in particular to a device and method for conducting sloshing experiments on a liquid tank model. Background Technology

[0002] In the field of marine structures, swaying generally refers to the movement of liquids and gases within liquid-filled tanks, exhibiting strong randomness and nonlinearity. Swaying motion is prevalent in the liquid-filled tanks of marine structures such as cargo ships and offshore platforms. Swaying motion can lead to a loss of stability in marine structures, and severe swaying pressure can also impact the tank walls, potentially causing structural damage. Under external force excitation, marine structures exhibit a six-degree-of-freedom motion response. If a right-handed Cartesian coordinate system is established with a reference point in space as the origin, the motion response of these six degrees of freedom can be represented as translational motion along the x, y, and z axes, respectively called sway, pitch, and heave; and fixed-axis rotation about the x, y, and z axes, respectively called roll, pitch, and bow. Swaying motion is most prominent in the roll motion of marine structures, and roll has the greatest impact on marine structures.

[0003] To analyze the hydrodynamic characteristics of marine structures, primarily ships, and to study the sloshing phenomenon of liquids within tanks, the current mainstream experimental method involves placing a tank model in a wave-generating tank. Waves are generated in the tank using a wave-generating mechanism, causing the tank model to exhibit the aforementioned motion response under the influence of the incident waves. This results in sloshing of the liquid within the tank, allowing for the investigation of its hydrodynamic characteristics and verification of the effectiveness of related theoretical analysis methods. However, most current experimental setups simulate the motion response of the tank using mechanical devices, rather than the actual motion response under wave excitation, leading to errors in the experimental results. For example, the utility model patent CN209656248U discloses a hydraulic arm-type tank sloshing simulation experimental device. Furthermore, the waves simulated in a two-dimensional wave tank are two-dimensional, which differs significantly from the three-dimensional waves encountered by marine structures in real sea areas. The motion response of the tank model also fails to accurately reflect actual motion. For instance, the invention patent CN111537191B discloses an experimental device for a two-dimensional sloshing response tank under wave action. Summary of the Invention

[0004] Purpose of the invention: The purpose of this invention is to provide an apparatus and method for conducting swaying experiments on liquid tank models in a three-dimensional wave pool, capable of simulating the motion response of real wave excitation.

[0005] Technical Solution: The present invention provides a device for a liquid tank model swaying experiment, comprising a support mechanism, a displacement limiting mechanism for the liquid tank model, the liquid tank model, and a three-dimensional wave pool. The support mechanism is disposed within the three-dimensional wave pool. The displacement limiting mechanism includes an optical axis and a limiting module sleeved on the optical axis. The upper end of the optical axis is connected to the top of the support mechanism, and the lower end of the optical axis is connected to the experimental liquid tank model. The limiting module is disposed at the connection between the optical axis and the experimental liquid tank model. The limiting module is used to limit the pitching, yawing, and swaying motions of the liquid tank model and to release the restricted degrees of freedom of the liquid tank model in the roll, sway, and heave directions.

[0006] Furthermore, the limiting module includes a fixed chuck, a bearing, a slide groove, a slider, and a slider displacement limiter. The fixed chuck is fixedly connected to the liquid tank model, the bearing is embedded in the fixed chuck, the slide groove is slidably connected to the bearing, the slide groove is fixedly connected to the slider, the slider is slidably connected to the optical axis, and the slider displacement limiter is located at the bottom of the optical axis to prevent the experimental liquid tank model from undergoing excessive displacement due to wave excitation, which could cause the box-type slider to detach from the linear optical axis and invalidate the experimental measurement results.

[0007] Furthermore, the bearing housing is equipped with a bearing displacement limiter, and the slide groove is slidably connected with a slide groove displacement limiter. The slide groove displacement limiter and the bearing displacement limiter are fixedly connected, and the slide groove is fixedly connected to the slider through a fixed connector.

[0008] Furthermore, the displacement limiting mechanism has two sets symmetrically arranged on both sides of the limiting liquid tank model. Each set of displacement limiting mechanism has two optical axes, and the fixed chuck is fixed between the two optical axes.

[0009] Furthermore, the support mechanism includes a fixed support, a bow side platform and a stern side platform fixedly connected to the top of the fixed support, and a starboard side beam, a port side beam and a central beam are provided between the bow side platform and the stern side platform. A detachable guide shaft support is provided on the central beam, and the guide shaft support is fixedly connected to the optical axis.

[0010] Furthermore, the central beam includes a starboard central beam, a port central beam, a starboard reinforcing central beam, and a port central reinforcing beam. The starboard and port central beams are symmetrically arranged. The starboard and port central reinforcing beams are vertically arranged above the starboard and port central beams. The starboard central reinforcing beam is fixedly connected to the bow platform and stern platform via a first bow reinforcing support and a first stern reinforcing support. The port central reinforcing beam is fixedly connected to the bow platform and stern platform via a second bow reinforcing support and a second stern reinforcing support.

[0011] Furthermore, four guide shaft supports are provided, symmetrically arranged on the starboard side center reinforcing beam and the port side center reinforcing beam.

[0012] Furthermore, the liquid tank model is equipped with a pressure sensor, a wave height meter, and a small nine-axis attitude sensor. A marker ball for a six-degree-of-freedom motion non-contact optical measuring instrument is installed on the deck of the liquid tank model. The small nine-axis attitude sensor provides a data foundation for studying the phenomenon and mechanism analysis of wave-induced liquid sloshing within the tank. The wave height meter is used to measure the free surface change of the liquid inside the tank under external wave excitation, and the pressure sensor is used to measure the impact of the liquid sloshing motion on the tank walls.

[0013] Furthermore, the bearing is a ceramic bearing, the slide is a ceramic slide, and the fixing connector is an aluminum fixing connector.

[0014] The present invention provides a liquid tank model sloshing experiment method, using the liquid tank model sloshing experiment apparatus as described above, specifically including the following steps:

[0015] S1: Determine the experimental conditions and the wave angle of the liquid tank model;

[0016] S2: Based on the wave angle determined in S1, install the support system in a three-dimensional wave pool or open water.

[0017] S3: Install the experimental liquid tank model onto the liquid tank displacement limiting system;

[0018] S4: Install the liquid tank displacement limiting system and the completed experimental liquid tank model onto the support system. Determine the height of the liquid tank model from the bottom of the pool or water body according to the experimental conditions and adjust the height of the experimental liquid tank model by adjusting the slider on the linear optical axis.

[0019] S5: Install the pressure sensor, wave height meter, small nine-axis attitude meter, and marker ball into the liquid tank, and install motion capture cameras on both sides of the water pool to complete the installation of the experimental device and measuring equipment.

[0020] S6: Start wave generation and record data from the various measuring instruments installed inside the experimental liquid tank model and on the support system;

[0021] S7: After completing the experiment, dismantle the entire experimental apparatus in the reverse order of S3 and S4.

[0022] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: (1) It can make the liquid tank model in a three-dimensional wave pool or open water area according to the experimental research needs, and release the three motions of swaying, heaving and rolling to conduct liquid tank sloshing experiments by setting the wave-facing angle; (2) With the wave surface information monitored by the pressure sensor and wave height meter installed in the liquid tank model, the motion response characteristics of the liquid tank in the waves and the free liquid surface change characteristics of the liquid sloshing motion in the tank can be obtained, and the effectiveness of the relevant numerical simulation analysis method can be verified. Attached Figure Description

[0023] Figure 1 This is an exploded view of the structure of the device described in this invention;

[0024] Figure 2 This is a schematic diagram of the support system structure described in this invention;

[0025] Figure 3 This is a schematic diagram of the displacement limiting system for the liquid tank model described in this invention;

[0026] Figure 4 This is a simulation diagram of the experiment described in this invention. Detailed Implementation

[0027] The technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0028] The present invention provides a device for a liquid tank model sloshing experiment, such as... Figure 1 As shown, the device includes a support mechanism 1, a liquid tank model displacement limiting mechanism 2, and an experimental liquid tank model 3. The support mechanism 1 is installed in a three-dimensional wave pool or open water to support and fix the entire device, and an ultrasonic wave height meter can be additionally installed on it to monitor wave information. The liquid tank model displacement limiting mechanism 2 is connected to the guide shaft support 113 by fastening screws, and is installed on the starboard side center crossbeam 103, port side center crossbeam 105, starboard side center reinforcing crossbeam 104, and port side center reinforcing crossbeam 106 of the support mechanism 1, and is used to fix and limit the degree of freedom of movement of the experimental liquid tank model 3.

[0029] like Figure 2As shown, the support mechanism 1 includes a bow-side platform 101, a stern-side platform 102, a starboard-side center crossbeam 103, a starboard-side center reinforcing crossbeam 104, a port-side center crossbeam 105, a port-side center reinforcing crossbeam 106, a starboard-side crossbeam 107, a port-side crossbeam 108, a bow-side starboard-side reinforcing support 109, a bow-side port-side reinforcing support 110, a stern-side starboard-side reinforcing support 111, a stern-side port-side reinforcing support 112, a guide shaft support 113, and a fixed bracket 114. All beams within the support structure are fastened together with bolts and nuts. The starboard side center reinforcing beam 104, the port side center reinforcing beam 106, and their corresponding starboard side center beams 103 and port side center beams 105 are arranged perpendicularly in the same plane. The two ends of the starboard side center beams 103 and 105 are fastened to the bow side platform 101 and the stern side platform 102 with bolts and nuts. The first bow side reinforcing support 109 and the second bow side reinforcing support 110 are fastened to the bow side platform with bolts and nuts. On platform 101; the first stern-side reinforcing support 111 and the second stern-side reinforcing support 112 are fastened to the stern-side platform 102 by bolts and nuts; the two ends of the starboard side center reinforcing crossbeam 104 and center reinforcing crossbeam 106 are fastened to the corresponding bow-side reinforcing support and stern-side reinforcing support by bolts and nuts; the symmetrically arranged guide shaft supports 113 are connected and fixed to the center reinforcing crossbeams 104 and 106 by screws, and the symmetrically arranged guide shaft supports 113 are used to install and fix the liquid tank model displacement limiting mechanism 2.

[0030] like Figure 3 As shown, the liquid tank model displacement limiting system 2 includes a fixed chuck 21, a ceramic bearing 22, a bearing displacement limiter 23, a slide groove displacement limiter 24, a ceramic slide groove 25, an aluminum fixed connector 26, a box-type slider 27 with bearings, a linear optical axis 28, and a slider displacement limiter 29. The ceramic bearing 22 is embedded in the central groove of the matching fixed chuck 21. The cylindrical portion of the bearing displacement limiter 23 is inserted into the ceramic bearing 22, and the square portion is connected to the square portion of the slide groove displacement limiter 24. The rounded rectangular column of the slide groove displacement limiter is inserted into the groove of the ceramic slide groove 25. The aluminum fixed connector 26 is connected to the ceramic slide groove 25 by screws. The box-type slider 27 is connected to the aluminum fixed connector 26 by bolts and nuts. The box-type slider 27 mates with the linear optical axis 28. The slider displacement limiter 29 is connected to the end of the linear optical axis 28 by fastening screws.

[0031] like Figure 4As shown, during the actual experimental operation, pressure sensors and wave height meters are installed on the walls of the experimental liquid tank model 3 to collect the impact force on the inner wall of the experimental liquid tank model 3 and the free liquid level inside the tank during the experiment. Two symmetrical fixed chucks 21 are symmetrically connected to both sides of the experimental liquid tank model 3, with the axes of the fixed chucks 21 and the ceramic bearings 22 located at the rotation center of the experimental liquid tank model 3. The ceramic bearings 22, which are fitted onto the bearing displacement limiter 23, are embedded into the central groove of the fixed chucks 21, allowing the experimental liquid tank model 3 to perform free lateral rolling motion under the excitation of three-dimensional waves. The slide displacement limiter 24 is connected to the bearing displacement limiter 23 with bolts and nuts, and the rounded rectangular column of the slide displacement limiter 24 is placed into the groove of the ceramic slide 25, allowing the experimental liquid tank model 3 to perform free swaying motion under the excitation of three-dimensional waves. The aluminum fixed connector 26 is installed on the ceramic slide 25 with screws, and the aluminum fixed connector 26 is connected to the box-type slider 27 with bolts and nuts. The box-type slider 27 is installed on the linear optical axis 28, allowing the experimental liquid tank model 3 to perform free heaving motion under the excitation of three-dimensional waves. The linear optical axis 28 is fixed to the support system 1 by the fastening screws in the guide shaft support 113. In this way, the liquid tank displacement limiting system 2 is installed and fixed on the support system 1, and the fixation and displacement limitation and release of the experimental liquid tank model 3 are completed.

[0032] The displacement limiting mechanism for the liquid tank model decomposes the motion of the experimental liquid tank model into rotational motion around the x-axis and translational motion along the y-axis and z-axis. The z-axis is vertical, pointing upwards from the horizontal plane, and the y-axis represents the direction of wave propagation. The x-axis is perpendicular to the y-axis and z-axis, forming a right-handed rectangular coordinate system. The displacement limiting system releases the lateral, swaying, and heaving motions of the experimental liquid tank model through the cooperation of bearings, grooves, and sliders, while limiting the model's motion in other degrees of freedom. Specifically, the normal direction of the plane containing the fixed chuck is parallel to the x-axis. The ceramic bearing is fitted into the central groove of the fixed chuck, allowing it to rotate around the x-axis under wave excitation, while the fixed disk only rotates around the x-axis. The ceramic bearing is fitted into the cylindrical part of the bearing displacement limiter, allowing the experimental liquid tank model to laterally roll around the x-axis after being excited by waves. The ceramic chute is parallel to the y-axis. The rounded rectangular column of the chute displacement limiter is adapted to the ceramic chute. Under wave excitation, the chute displacement limiter can translate along the y-axis within the chute. Alternatively, the chute displacement limiter can move only in the y-axis direction. By placing the chute displacement limiter within the ceramic chute and connecting it to the bearing displacement limiter via bolts and nuts, the liquid tank model displacement limiting system and the experimental liquid tank model will perform lateral oscillation in the y-axis direction after being subjected to wave excitation. The linear optical axis is parallel to the z-axis. Under wave excitation, the experimental liquid tank model and the liquid tank model displacement limiting system drive the box-type slider to move along the linear optical axis in the z-axis direction. The box-type slider can move only in the z-axis direction. By placing the box-type slider on the linear optical axis and connecting it via bolts, nuts, and aluminum fixing connectors, the liquid tank model displacement limiting system and the experimental liquid tank model will perform helical oscillation in the z-axis direction after being subjected to wave excitation.

[0033] The method for conducting a liquid tank model sloshing experiment using the apparatus described above includes the following steps:

[0034] S1: Determine the experimental conditions and the wave angle of the liquid tank model;

[0035] S2: Based on the wave angle determined in S1, install the support system in a three-dimensional wave pool or open water.

[0036] S3: Install the experimental liquid tank model onto the liquid tank displacement limiting system;

[0037] S4: Install the liquid tank displacement limiting system and the completed experimental liquid tank model onto the support system. Determine the height of the liquid tank model from the bottom of the pool or water body according to the experimental conditions and adjust the height of the experimental liquid tank model by adjusting the slider on the linear optical axis.

[0038] S5: Install the pressure sensor, wave meter, and marker ball into the liquid tank, and install motion capture cameras on both sides of the water pool to complete the installation of the experimental device and measuring equipment.

[0039] S6: Start wave generation and record data from the various measuring instruments installed inside the experimental liquid tank model and on the support system;

[0040] S7: After completing the experiment, dismantle the entire experimental apparatus in the reverse order of S3 and S4.

Claims

1. A device for a liquid tank model swaying experiment, comprising a liquid tank model (3) and a three-dimensional wave pool, characterized in that, It also includes a support mechanism (1) and a displacement limiting mechanism (2) for the liquid tank model. The support mechanism (1) is set in a three-dimensional wave pool. The displacement limiting mechanism (2) includes an optical axis (28) and a limiting module sleeved on the optical axis (28). The upper end of the optical axis (28) is connected to the top of the support mechanism (1), and the lower end of the optical axis (28) is connected to the experimental liquid tank model (3). The limiting module is set at the connection between the optical axis (28) and the experimental liquid tank model (3). The limiting module is used to limit the pitching, yaw, and swaying motion of the liquid tank model (3) and release the degree of freedom of motion of the liquid tank model (3) in the yaw, sway, and heave directions. The limiting module includes a fixed chuck (21), a bearing (22), a slide (25), a slider (27), and a slider displacement limiter (29). The fixed chuck (21) is fixedly connected to the liquid tank model (3). The bearing (22) is embedded in the fixed chuck (21), the slide groove (25) is slidably connected to the bearing (22), the slide groove (25) is fixedly connected to the slider (27), the slider (27) is slidably connected to the optical axis (28), and the slider displacement limiter (29) is located at the bottom of the optical axis (28); the bearing (22) is covered with a bearing displacement limiter (23), the slide groove (25) is slidably connected with a slide groove displacement limiter (24), the slide groove displacement limiter (24) and the bearing displacement limiter (23) are fixedly connected, and the slide groove (25) is fixedly connected to the slider (27) through a fixed connector (26); the displacement limiting mechanism (2) has two sets symmetrically arranged on both sides of the limiting liquid tank model (3), each set of displacement limiting mechanism (2) has two optical axes (28), and the fixed chuck (21) is fixed between the two optical axes (28); The support mechanism (1) includes a fixed support (114), a bow side platform (101) and a stern side platform (102) fixedly connected to the top of the fixed support (114). A starboard side beam (107), a port side beam (108) and a central beam are provided between the bow side platform (101) and the stern side platform (102). A detachable guide shaft support (113) is provided on the central beam. The guide shaft support (113) is fixedly connected to the optical axis (28).

2. The apparatus for the liquid tank model sloshing experiment according to claim 1, characterized in that, The central beam includes a starboard central beam (103), a port central beam (105), a starboard central reinforcing beam (104), and a port central reinforcing beam (106). The starboard central beam (103) and the port central beam (105) are symmetrically arranged, and the starboard central reinforcing beam (104) and the port central reinforcing beam (106) are arranged perpendicularly to the starboard central beam (103) and the port central beam (105). Above, the starboard side center reinforcing beam (104) is fixedly connected to the bow side platform (101) and the stern side platform (102) through the first bow side reinforcing support (109) and the first stern side reinforcing support (111), and the port side center reinforcing beam (106) is fixedly connected to the bow side platform (101) and the stern side platform (102) through the second bow side reinforcing support (110) and the second stern side reinforcing support (112).

3. The apparatus for the liquid tank model sloshing experiment according to claim 2, characterized in that, The guide shaft support (113) is provided in four parts, symmetrically arranged on the starboard side center reinforcing beam (104) and the port side center reinforcing beam (106).

4. The apparatus for the liquid tank model sloshing experiment according to claim 1, characterized in that, The liquid tank model (3) is equipped with a pressure sensor, a wave height meter, and a small nine-axis attitude meter. The liquid tank model (3) is equipped with a marker ball for a six-degree-of-freedom motion non-contact optical measuring instrument.

5. The apparatus for the liquid tank model sloshing experiment according to claim 1, characterized in that, The bearing (22) is a ceramic bearing, the slide (25) is a ceramic slide, and the fixing connector (26) is an aluminum fixing connector.

6. A method for conducting a sloshing experiment on a liquid tank model, characterized in that, Using the apparatus for sloshing experiments on a liquid tank model as described in any one of claims 1-5, specifically Includes the following steps: S1: Determine the experimental conditions and the wave angle of the liquid tank model; S2: Based on the wave angle determined in S1, install the support system in a three-dimensional wave pool or open water. S3: Install the experimental liquid tank model onto the liquid tank displacement limiting system; S4: Install the liquid tank displacement limiting system and the completed experimental liquid tank model onto the support system. Determine the height of the liquid tank model from the bottom of the pool or water body according to the experimental conditions and adjust the height of the experimental liquid tank model by adjusting the slider on the linear optical axis. S5: Install the pressure sensor, wave height meter, nine-axis attitude meter, and marker ball into the liquid tank, and install motion capture cameras on both sides of the water pool to complete the installation of the experimental device and measuring equipment. S6: Start wave generation and record data from the various measuring instruments installed inside the experimental liquid tank model and on the support system; S7: After completing the experiment, dismantle the entire experimental apparatus in the reverse order of S3 and S4.

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