Device and method for simulating bubble plume evolution in cold spring area under seawater disturbance

Abstract

According to the device and method for simulating bubble plume evolution in the cold spring area under seawater disturbance provided by the invention, through collaborative design of gassing type bubble generation, pressure modulation control and lateral disturbance application, multi-physical field joint regulation and control of bubble release and movement processes are realized; the device comprises a reaction cabin, a gassing type bubble module, a cabin pressure adjusting module, a seawater disturbance coupling module, a temperature control module and a multi-mode synchronous monitoring module, the multi-mode synchronous monitoring module comprises a particle image velocity measurement system and an acoustic monitoring unit, the acoustic monitoring unit is arranged in the reaction cabin, and the particle image velocity measurement system is aligned with the transparent window of the reaction cabin; an acoustic monitoring unit is combined with a particle image velocimetry (PIV) observation result to form a PIV-acoustic dual observation system, and synchronous acquisition of bubble plume form evolution, flow field structure change and methane flux response characteristics is realized.

Description

Technical Field

[0001] This invention relates to the technical field of marine cold seep simulation and multiphase flow experimental devices, specifically to a device and method for simulating the evolution of bubble plumes in cold seep areas under seawater disturbance, used for coupled experiments of methane bubble plumes and seawater disturbance in cold seep environments. Background Technology

[0002] In deep-sea cold seep systems, after methane enters the water in bubble form, its subsequent transport and diffusion processes are not solely determined by the bubble's own buoyancy dynamics; the surrounding seawater flow conditions also play a crucial modulating role. In actual marine environments, cold seep areas often exhibit multi-scale seawater movement processes, including background ocean currents, tidal currents, internal wave disturbances, and local shear flows. This results in bubble plumes generally exhibiting significant deflection, oscillation, diffusion, and non-axisymmetric evolution characteristics during their ascent. These seawater disturbances not only alter the spatial morphology and ascent path of the bubble plumes but also significantly affect bubble residence time, coalescence and breakup behavior, and induced flow field structure, thereby further controlling the transport efficiency and environmental effects of methane in the water.

[0003] Unlike ideal bubble plumes that are approximately axisymmetric under still water conditions, cold seep plumes under the influence of ocean currents or disturbed flow fields often exhibit complex morphologies such as inclined upward movement, serpentine oscillations, or intermittent bifurcation. Their macroscopic structure and local dynamic characteristics are highly dependent on the magnitude, direction, and temporal variation of the applied flow velocity. Therefore, the geometric morphology, axis deflection angle, and their evolution with altitude of the plume are considered important information carriers reflecting the local seawater flow state in the cold seep area. However, due to the harsh conditions of the deep-sea environment, achieving precise in-situ observation of the coupling process between cold seep plumes and seawater disturbances still faces significant technical challenges. Therefore, experimental simulation methods are commonly used in this research.

[0004] However, existing experimental studies still have certain limitations. Most studies use methods such as gas source leakage, hydrate decomposition, or artificial injection to generate bubble plumes. Although a large amount of bubble observation data has been accumulated, the bubble release rate is often quite violent, accompanied by strong flow field disturbances, and the bubble size and generation frequency are highly random, making it difficult to achieve simultaneous and accurate observation of bubble morphology, hydrate generation process, and flow field structure in the same experimental system. For example, Chinese invention patent CN117672065B proposes a seabed bubble plume imaging simulation platform and simulation method, which ejects gas and water simultaneously, placing the entire life cycle of the bubbles in an artificially set flow field. This cannot reflect the evolution process after the natural generation of bubbles and is difficult to apply to cold seep environments. Another example is Chinese invention patent CN120740873B, which proposes an acoustic-optical fusion method, system, device, and storage medium for cold seep methane detection. It mainly uses sonar and underwater high-speed cameras to perform acoustic and optical imaging observations of bubble plumes, focusing on target identification and morphological recording, but has limited quantitative detection capabilities for flow field structure and bubble motion.

[0005] Chinese invention patent CN102331511B proposes a high-frequency image acquisition and flow field visualization method based on particle image velocimetry (PIV), which can measure the fluid velocity field. However, this method is mainly designed for single-phase or weak two-phase flow fields and does not systematically incorporate the methane bubble formation and hydrate shell evolution process in cold seep environments, making it difficult to achieve coupled feature identification of bubble dynamics and phase change processes. Furthermore, when directly applying PIV technology in gas-liquid two-phase systems, the strong reflection from the bubble surface and its unstable release process easily interfere with the imaging quality, leading to significant local velocity vector fluctuations.

[0006] Therefore, there is an urgent need for a device and method for simulating the evolution of bubble plumes in cold seeps under seawater disturbance, which can stably construct methane bubble plumes under controllable pressure conditions and independently control the intensity and structure of seawater disturbance, so as to realize the synchronous monitoring of bubble plume evolution, flow field structure changes and methane flux characteristics. Summary of the Invention

[0007] To address the aforementioned technical problems in existing cold seep bubble experiments, this invention provides an apparatus and method for simultaneous visual observation of methane bubble plumes and hydrate shells in a cold seep environment. This apparatus can simulate the deep-sea cold seep environment under controllable temperature and pressure conditions, reproducing the processes of methane bubble escape, hydrate formation, and flow field evolution. Through particle image velocimetry (PIV) technology, it achieves simultaneous high-resolution visual observation of the bubble, hydrate shell, and flow field structure, thereby obtaining the dynamic characteristics, phase transition laws, and methane migration mechanisms of the cold seep plume.

[0008] In cold seep environments, bubbles are initially formed by gas evolution, and then gradually interact with the surrounding seawater during their ascent to form a complete plume structure. Therefore, to better study the influence of environmental water bodies on the formation of plumes in cold seep environments, the technical solution adopted in this invention is: a simulation device for the evolution of bubble plumes in cold seep areas under seawater disturbance. Unlike existing devices that only focus on bubble generation or flow field disturbance, this invention achieves multi-physics joint control of bubble release and movement processes through a synergistic design of gas evolution-type bubble generation, pressure modulation control, and lateral disturbance application.

[0009] The device includes: a reaction chamber equipped with a transparent viewing window;

[0010] The gas-evolving bubble module is connected to the lower part of the reaction chamber to create a supersaturated environment for dissolved methane and induce the dissolved methane to precipitate and form a bubble plume through pressure control, which is used to provide a bubble plume source for the reaction chamber.

[0011] The chamber pressure regulation module is connected to the upper part of the reaction chamber and is used to stabilize the internal pressure environment of the reaction chamber.

[0012] The seawater disturbance coupling module is connected to the side of the reaction chamber and is used to construct a controllable seawater disturbance flow field inside the reaction chamber.

[0013] Temperature control module, used for temperature control of gas evolution bubble module and reaction chamber;

[0014] The multimodal synchronous monitoring module includes a particle image velocimetry (PIV) system and an acoustic monitoring unit. The acoustic monitoring unit is deployed inside the reaction chamber to monitor the spatial distribution and flux characteristics of the methane bubble plume in real time. The particle image velocimetry system is aligned with the transparent window of the reaction chamber to acquire visual images of the bubble plume and measure the velocity distribution of the flow field inside the reaction chamber, forming a PIV-acoustic dual observation system to achieve synchronous acquisition of the bubble plume morphology evolution, flow field structure changes and methane flux response characteristics.

[0015] The computer is electrically connected to the gas evolution bubble module, the chamber pressure regulation module, the seawater disturbance coupling module, the temperature control module, and the multimodal synchronous monitoring module, respectively.

[0016] Furthermore, the gas-evolving bubble module includes a gas source, a pressure regulating chamber assembly, and a pressure sensor.

[0017] The pressure regulating chamber assembly includes an upper pressure regulating chamber and a lower pressure regulating chamber, with a connecting channel between the upper and lower pressure regulating chambers. A push rod assembly is also provided on the connecting channel. The connecting channel can be opened or closed by retracting or extending the push rod assembly. A piston is movably connected to the bottom of the lower pressure regulating chamber. The volume of the lower pressure regulating chamber can be changed by the movement of the piston.

[0018] The air source is connected to the lower pressure regulating chamber; pressure sensor number one is located inside the lower pressure regulating chamber.

[0019] Furthermore, the chamber pressure regulation module includes an air chamber, a flexible membrane, and a second pressure sensor located at the top of the reaction chamber. The air chamber is connected to an air source via an air supply pipeline and is used to apply external pressure to one side of the flexible membrane. The flexible membrane is located between the air chamber and the fluid inside the reaction chamber, and its lower part is in direct contact with the liquid inside the reaction chamber, used to transmit the air chamber pressure to the inside of the reaction chamber. The second pressure sensor is used to monitor the pressure changes inside the air chamber in real time.

[0020] Furthermore, the flexible membrane is arranged at an angle, and its inclined structure helps to prevent bubbles from lingering and accumulating below the membrane surface, reducing interference with the flow field and bubble plume morphology in the reaction chamber, and improving the uniformity and stability of pressure transmission.

[0021] Furthermore, the seawater disturbance coupling module includes a water tank, a flow guide pipe, a valve assembly, and an orifice plate assembly; a disturbance interface is provided on the side wall of the reaction chamber, and the water tank is connected to the disturbance interface through the flow guide pipe to provide disturbed water to the reaction chamber. A valve assembly is provided on the flow guide pipe, and the orifice plate assembly is located between the flow guide pipe and the reaction chamber.

[0022] Furthermore, the temperature control module includes a constant temperature water bath system, a constant temperature water bath jacket, and a temperature sensor. The constant temperature water bath system includes a constant temperature water bath tank, a heating unit, a circulation pump, and circulation pipelines. The constant temperature water bath tank is connected to the circulation pipelines, the circulation pipelines are connected to the circulation pump, and the heating unit is connected to the circulation pipelines. The constant temperature medium is transported to the constant temperature water bath jacket by the circulation pump and returned to the water bath tank via the return pipeline. There are two constant temperature water bath jackets, which are respectively wrapped around the reaction chamber and the regulating pressure chamber assembly.

[0023] Furthermore, the particle image velocimetry system includes a light source, a camera, a laser, and a control unit. The camera, light source, and laser are opposite to a transparent viewing window. The light source, camera, and laser are each connected to the control unit, and the control unit is electrically connected to a computer.

[0024] This invention also proposes a coupled experimental method for methane bubble plume-seawater disturbance in a cold seep environment, based on the aforementioned simulation device for the evolution of cold seep bubble plumes under seawater disturbance, comprising the following steps:

[0025] S1. Device installation;

[0026] S2. The device operates and generates bubbles: The piston of the gas evolution bubble module reciprocates, changing the effective volume of the pressure regulating chamber of the gas evolution bubble module under sealed conditions, thereby controlling the pressure inside the chamber and causing the pressure inside the pressure regulating chamber to change stepwise or slowly. When the pressure drops to the point where the dissolution equilibrium condition changes, it induces dissolved methane to precipitate from the dissolved state to the free state, forming a bubble-water mixture.

[0027] S3. Bubble Stream Injection and Cold Seep Channel Mode Control: When the pressure in the lower regulating chamber reaches the preset threshold, the push rod of the gas-evolving bubble module retracts, the lower regulating chamber connects with the upper regulating chamber, and the bubble-water mixture formed in the lower regulating chamber enters the upper regulating chamber under the action of pressure difference to form a cold seep channel mode, and is further automatically injected into the reaction chamber through the connecting channel to form a methane bubble stream in the reaction chamber.

[0028] S4. Application of seawater disturbance and construction of DC disturbance flow field: After completing the injection of bubble plume in S3 and stabilizing the internal pressure of the reaction chamber under the action of the chamber pressure regulation module, experimental water is injected into the water tank of the seawater disturbance coupling module and the flow guide pipe is opened. The water enters the disturbance interface on the side wall of the reaction chamber under the action of the pump. Before the disturbed water enters the reaction chamber through the flow guide pipe, it is rectified by the orifice plate assembly set at the disturbance interface. The water flow entering the reaction chamber is transformed from the original unstable flow state into a stable lateral flow with uniform velocity distribution and small pulsation, thereby constructing an approximately DC seawater disturbance flow field in the reaction chamber.

[0029] By adjusting the liquid level in the water tank, the flow rate in the guide pipe, and the aperture and opening ratio of the orifice plate assembly, the intensity and velocity distribution of the disturbance flow can be changed, thus enabling the construction of different disturbance conditions without changing the overall pressure conditions of the reaction chamber.

[0030] S5. Multimodal Synchronous Monitoring: After completing the construction of the S4 DC-type seawater disturbance flow field, the multimodal monitoring system is activated to synchronously observe and acquire data on the evolution of the methane bubble plume in the reaction chamber. The particle image velocimetry system is used to acquire image sequences of the bubble plume, and the images are segmented and feature extracted to obtain the bubble projected area, contour morphology, bubble number density and spatial distribution, and to measure the velocity distribution of the flow field in the reaction chamber and the motion characteristics of the bubble swarm. At the same time, the acoustic monitoring unit is used to collect the acoustic scattering or echo signals generated by the bubble plume. The above particle image velocimetry and acoustic data are uniformly transmitted to the computer to realize the time-synchronous acquisition, fusion processing and storage of multi-source data.

[0031] Furthermore, it also includes step S6,

[0032] Calculating the overall flux of the plume: The velocity distribution of the continuous phase flow field is measured using a particle image velocimetry system, and the instantaneous velocity and trajectory of the bubble swarm are obtained by combining bubble image tracking / cross-correlation calculations, thus yielding the bubble velocity. Simultaneously, acoustic scattering / echo signals of the plume are collected using acoustic monitoring units deployed inside or on the bulkhead of the reaction chamber, and the echo amplitude is extracted. and correlate it with the bubble volume fraction Correlation calibration is performed to establish acoustic amplitude. With bubble volume fraction The quantitative mapping relationship between them

[0033] Bubble speed Represented as:

[0034]

[0035] in, The centroid positions of the same bubble in two adjacent frames. Let z be the time interval between the two particles, z be the height of the center of mass, and t be the time.

[0036] bubble volume fraction Represented as:

[0037]

[0038] Where r is the distance from the transducer to the sampling volume, β is the medium absorption coefficient, and k is an empirical calibration coefficient, the echo amplitude is extracted. ;

[0039] methane bubble volume flux Represented as:

[0040]

[0041] in, The volume fraction of bubbles obtained from acoustic signal inversion. Let A be the average rising velocity of the bubble swarm, and let A be the cross-sectional area of ​​the plume.

[0042] Compared with existing technologies, the technical effects and advantages of this invention are as follows:

[0043] 1. This invention regulates bubble generation through a gas evolution bubble generation structure and structurally couples it with the lateral disturbance application process of the reaction chamber during the bubble rise phase. The entire process incorporates a pressure control module. This collaborative design establishes a synergistic control relationship between bubble generation, pressure evolution, and lateral flow, thereby overcoming the limitations of existing technologies where bubble generation conditions and disturbance effects are independent, making it difficult to systematically control bubble dynamics.

[0044] 2. This invention employs a gas evolution-type bubble generation and pressure-triggered release mechanism. By precisely controlling the effective volume and pressure state of the down-regulating chamber, it achieves controllable precipitation of methane from a dissolved state to a free state. This avoids the strong disturbances and randomness of bubble size caused by traditional direct jet injection, making the bubble source term more stable and significantly improving the consistency and comparability of experimental results.

[0045] 3. This invention couples the reaction chamber structure with the seawater disturbance application unit. Through the water tank, the flow guide pipe and the orifice plate rectification structure, a stable and near-DC disturbance flow is constructed in the reaction chamber. Compared with random disturbance or strong jet method, it can more accurately characterize the influence of seawater disturbance on the evolution of bubble plume and improve the controllability and repeatability of disturbance conditions.

[0046] 4. This invention constructs a PIV-acoustic multimodal synchronous monitoring system, which can simultaneously acquire information on bubble plume morphology, flow field velocity structure and acoustic response under the same experimental conditions, and achieve comprehensive characterization of bubble plume evolution process and methane flux change, overcoming the limitation that a single monitoring method is difficult to fully reflect plume characteristics.

[0047] 5. The innovative design of this invention incorporates a structure for applying seawater disturbance and combines it with the transparent window of the reaction chamber, achieving coordinated arrangement in terms of spatial location and flow direction. It simultaneously supports real-time visualization observation of the seawater disturbance process and the bubble plume evolution region, significantly improving the simulation accuracy and observation precision of the bubble plume evolution process under the influence of seawater disturbance.

[0048] 6. This invention achieves stable generation and repeatable release of methane bubble plumes through a synergistic structure of "gas evolution bubble generation - pressure modulation control - lateral disturbance application". It also combines acoustic detection and PIV measurement to simultaneously obtain plume morphology, flow field structure and flux change characteristics, providing a reliable experimental platform for revealing the modulation mechanism of seawater disturbance on the transport and diffusion process of methane bubble plumes in cold seep environments. Attached Figure Description

[0049] Figure 1 This is a schematic diagram of the overall structure of the device;

[0050] Figure 2 yes Figure 1 A magnified view of a portion of the image;

[0051] Figure 3 This is a schematic diagram of the cross-section of orifice plate A;

[0052] Figure 4 This is a schematic diagram of the cross-section of orifice plate B.

[0053] In the above figures: 101, gas tank; 102, buffer container; 103, push rod; 104, lower pressure regulating chamber; 105, hydraulic cylinder; 106, piston; 107, hydraulic pump; 108, hydraulic tank; 109, dual-cylinder pump; 111, electromagnetic reversing valve; 112, PLC controller; 113, sealing ring; 114, upper pressure regulating chamber; 201, water tank A; 202, water tank B; 203, reaction chamber; 204, orifice plate A; 205, orifice plate B; 206, gas chamber; 207, flexible membrane; 208. Pump; 301. Water bath; 302. No. 1 constant temperature water bath jacket; 303. No. 2 constant temperature water bath jacket; 401. Computer; 402. No. 1 electrically controlled valve; 403. Valve; 404. No. 2 electrically controlled valve; 405. No. 1 pressure sensor; 406. No. 3 electrically controlled valve; 407. No. 4 electrically controlled valve; 408. Temperature sensor; 409. No. 1 acoustic probe; 411. No. 2 acoustic probe; 412. Camera; 413. Light source; 414. No. 2 pressure sensor. Detailed Implementation

[0054] To facilitate understanding of the present invention by those skilled in the art, specific embodiments of the present invention will be described below with reference to the accompanying drawings.

[0055] To make the purpose, technical solution, and technical effects of this patent clearer, the embodiments of this patent are described in detail below with reference to the accompanying drawings. Unless otherwise specified, the embodiments and features described in the embodiments of this patent application can be arbitrarily combined to further improve the technical effects of this patent.

[0056] like Figure 1As shown, this invention proposes a simulation device for the evolution of bubble plumes in a cold seep region under seawater disturbance. The device mainly includes a reaction chamber, a gas-evolving bubble module, a chamber pressure regulation module, a seawater disturbance coupling module, a temperature control module, a multimodal synchronous monitoring module, and a computer. The gas-evolving bubble module is connected to the lower part of the reaction chamber, creating a supersaturated environment for dissolved methane and inducing the precipitation of dissolved methane to form a bubble plume through pressure control, thus providing a source term for the bubble plume in the reaction chamber. The chamber pressure regulation module is connected to the upper part of the reaction chamber to stabilize the internal pressure environment. The seawater disturbance coupling module is connected to the side of the reaction chamber to create a controllable seawater disturbance flow field inside the chamber. The temperature control module is used to control the temperature of the gas-evolving bubble module and the reaction chamber. The computer is electrically connected to the gas-evolving bubble module, the chamber pressure regulation module, the seawater disturbance coupling module, the temperature control module, and the multimodal synchronous monitoring module. The multimodal synchronous monitoring module includes a particle image velocimetry system and an acoustic monitoring unit. The acoustic monitoring unit is deployed inside the reaction chamber, while the particle image velocimetry system is aligned with the transparent viewing window of the reaction chamber. The acoustic monitoring unit, also deployed inside the reaction chamber, uses acoustic detection technology to monitor the spatial distribution and flux characteristics of the methane bubble plume in real time. This monitoring is combined with particle image velocimetry (PIV) observations to form a PIV-acoustic dual observation system, enabling the synchronous acquisition of bubble plume morphology evolution, flow field structure changes, and methane flux response characteristics.

[0057] The reaction chamber 203 is a sealed pressure vessel used to contain experimental water and serve as the main space for bubble plume evolution. Its body is made of pressure-resistant material to withstand internal pressure changes during the experiment. An interface connected to the chamber pressure regulation module is located at the top of the reaction chamber 203 to set and stabilize the internal pressure environment. An inlet connected to the gas evolution bubble module is located at the bottom of the reaction chamber 203 to introduce the bubble-water mixture output from the lower pressure regulating chamber 104 and / or the upper pressure regulating chamber 114 into the reaction chamber 203, forming the bubble plume source term. A disturbance interface is located on the side wall of the reaction chamber 203, connected to a seawater disturbance coupling module.

[0058] The reaction chamber is equipped with a transparent viewing window for imaging observation by the particle image velocimetry system.

[0059] The gas evolution bubble module is used to create a supersaturated environment for dissolved methane under controllable temperature and pressure conditions, and induces the dissolved methane to precipitate and form a bubble plume through pressure control, thereby achieving stable generation and repeated release of methane bubbles. For example... Figure 2 As shown, the module mainly includes a gas tank 101, a buffer container 102, a gas supply pipeline, a first electrically controlled valve 402, an upper pressure regulating chamber 114, a lower pressure regulating chamber 104, a hydraulic cylinder 105, a push rod 103, a hydraulic pump 107, a dual-cylinder pump 109, a fluid channel, and a first pressure sensor 405.

[0060] Gas tank 101 is used to store high-pressure methane gas. Its outlet is equipped with an electrically controlled valve 402 to control gas flow and prevent backflow. Gas tank 101 is connected to buffer container 102 via a pressure-resistant pipeline. Buffer container 102 is a sealed cavity that forms a pressure-stabilizing space to absorb instantaneous pressure fluctuations at the gas source, ensuring relatively stable pressure and flow rate of methane gas entering the subsequent system. The outlet of buffer container 102 is connected to a gas supply pipeline, which is further connected to a lower pressure regulating chamber 104, forming a methane gas supply path. A connecting channel is provided between the lower pressure regulating chamber 104 and the upper pressure regulating chamber 114. The opening / closing of the connecting channel is achieved by a push rod assembly 103. Push rod assembly 103 is connected to a hydraulic cylinder 105, which is connected to a hydraulic pump 107 and hydraulic tank 108 via a hydraulic circuit. The hydraulic cylinder 105 drives the push rod 103 to extend or retract under the control of the solenoid directional valve 111, so as to open or close the connecting channel, thereby switching the connection or disconnection state between the lower pressure regulating chamber 104 and the upper pressure regulating chamber 114.

[0061] During the operation of the device, the No. 1 pressure sensor 405 monitors the pressure in the lower pressure chamber 104 in real time. When the pressure in the lower pressure chamber 104 reaches the preset target value (or threshold), the PLC controller 112 outputs a control command based on the pressure signal, drives the solenoid directional valve 111 to switch to change the flow direction of the hydraulic oil, thereby controlling the hydraulic cylinder 105 to move and drive the push rod 103 to retract (or extend), so that the connecting channel switches from the closed state to the open state (or from the open state to the closed state).

[0062] After the channel is opened, the bubble-water mixture in the lower pressure regulating chamber 104 enters the upper pressure regulating chamber 114 through the connecting channel and further enters the reaction chamber 203, thus characterizing the process of the gas release channel changing from closed to open under specific pressure triggering conditions. By setting the pressure target value and the switching action sequence of the electromagnetic reversing valve 111, the on / off state of the connecting channel and the gas release rhythm can be coordinated and controlled, thereby simulating the start-up, continuous and intermittent characteristics of the methane release process in the cold seep environment, which is closer to the real situation.

[0063] After the pressure regulating chamber 104 forms a sealed space, the dual-cylinder pump 109 drives the piston 106 to produce displacement, causing a controllable change in the effective volume of the pressure regulating chamber 104, thereby causing the pressure inside the chamber to rise or fall. When the piston 106 moves upward (or inward) and causes the volume inside the chamber to decrease, the pressure inside the chamber increases and promotes the dissolution of methane in the water or maintains the dissolved state. When the piston 106 moves downward (or outward) and causes the volume inside the chamber to increase, the pressure inside the chamber decreases, causing the dissolution equilibrium conditions to change, thereby inducing the dissolved methane to precipitate from the dissolved state to the free state, forming a bubble-water mixture. By setting the displacement amplitude, movement speed, reciprocating frequency or period, and pressure holding time of piston 106, step changes, gradual changes, or periodic fluctuations in pressure of pressure chamber 104 can be achieved, thereby regulating the gas evolution intensity and bubble generation rate. This ensures that the generated bubble-water mixture has good stability and repeatability, and provides controllable source conditions for the subsequent formation of methane bubble plumes in reaction chamber 203 under the control of the second constant temperature water bath jacket 303.

[0064] The chamber pressure regulation module is used to set and stabilize the internal pressure environment of the reaction chamber 203. This module mainly includes an air chamber 206, a flexible membrane 207, and a second pressure sensor 414 located on the top of the reaction chamber 203.

[0065] The air chamber 206 is connected to the air source through an air supply line and is used to apply external pressure to one side of the flexible membrane 207.

[0066] The flexible membrane 207 is disposed between the gas chamber 206 and the fluid inside the reaction chamber 203, and its lower part is in direct contact with the liquid inside the reaction chamber 203. It is used to transmit the pressure of the gas chamber 206 to the inside of the reaction chamber without introducing additional gas. The gas chamber 206 and the flexible membrane 207 form an isolation interface, which is used to achieve stable maintenance and buffering of the pressure inside the chamber while maintaining a seal.

[0067] Furthermore, the flexible membrane 207 is arranged at an angle, and its inclined structure helps to prevent bubbles from lingering and accumulating below the membrane surface, reducing interference with the flow field and bubble plume morphology in the reaction chamber, and improving the uniformity and stability of pressure transmission.

[0068] Pressure sensor 414 is used to monitor pressure changes in the gas chamber 206 in real time. It is installed in the gas chamber 206 to provide a reference for the stable adjustment of the internal pressure environment of the reaction chamber 203.

[0069] The seawater disturbance coupling module provides a sealed, pressurized experimental space for the generation, rise, and evolution of methane bubble plumes under disturbance conditions, and constructs a controllable lateral seawater disturbance flow field inside the reaction chamber 203. In this embodiment, the seawater disturbance coupling module is connected to both sides of the reaction chamber. This module mainly includes water tank A 201, water tank B 202, orifice plate A 204, orifice plate B 205, valve assemblies, a flow guide pipe connected to the disturbance interface on the side wall of the reaction chamber 203, pump A, and pump B. The flow guide pipe is connected to water tank A 201 and water tank B 202 to provide disturbed water to the reaction chamber 203, thereby applying lateral flow. A valve assembly is installed on the flow guide pipe to regulate the flow rate of the disturbed water and control the opening and closing of the disturbance. The valve assembly includes a second electrically controlled valve 404, a third electrically controlled valve 406, and a fourth electrically controlled valve 407. An orifice plate assembly is disposed between the flow guide pipe and the reaction chamber 203, serving as a flow straightening component to turbulent the water flow. The orifice plate assembly includes orifice plate A 204 and orifice plate B 205. See also Figure 3 , 4 The water flow entering the disturbance channel is divided into multiple fine streams upon passing through orifice plate A 204 and / or orifice plate B 205, thereby suppressing velocity pulsations and large-scale vortex structures at the inlet. This results in a more uniform lateral velocity distribution in the reaction chamber 203, forming a stable, near-direct current lateral disturbance flow field. The aperture, thickness, and orifice ratio of orifice plate A 204 and orifice plate B 205 can be replaced or adjusted according to experimental requirements to achieve controllable settings for disturbance intensity and rectification effect, improving the repeatability and comparability of disturbance conditions.

[0070] A pump is used as the power unit to simulate seawater disturbance. In this embodiment, the pump includes pump A and pump B, which have the same structure and connection method to other components. Taking pump A as an example, it is located outside the reaction chamber 203 and is connected to the water tank A and the disturbance interface on the side wall of the reaction chamber through a pressure-resistant pipeline. It is used to draw experimental water from the water tank A and provide power for the disturbed water flow entering the reaction chamber. During the operation of the device, the pump acts as the active driving component for simulating seawater disturbance, and its output flow rate determines the velocity scale and momentum intensity of the disturbance flow. The water transported by the pump enters the side wall of the reaction chamber through the guide pipe and forms a stable submerged jet or a near-direct current lateral flow under the rectification effect of the orifice plate assembly, thereby constructing a controllable seawater disturbance flow field in the reaction chamber to simulate the influence of background ocean currents or local disturbances on the evolution of methane bubble plumes in a cold seep environment.

[0071] A sealing and fixing device is also installed on the disturbance pipeline for securing and sealing it. This device is located at the point where the disturbance pipeline passes through the reaction chamber on the side wall of reactor chamber 203. Its main function is to ensure a reliable and sealed connection between the disturbance pipeline and the reactor chamber body under high-pressure experimental conditions. The sealing and fixing device includes clamping components and fasteners, and sealing gaskets or sealing rings. This device firmly fixes the disturbance pipeline to the side wall of the reactor chamber using clamping components and fasteners. Simultaneously, a sealing gasket or sealing ring is placed between the outer wall of the pipeline and the chamber wall, forming a stable sealing interface under axial compression to prevent water leakage during the experiment. The sealing and fixing device not only ensures the sealing integrity of the disturbed water flow under high-pressure conditions but also effectively suppresses pipeline vibration caused by pump operation or flow fluctuations, preventing disturbance loads from directly acting on the reactor chamber body, thereby improving the operational stability and safety of the entire seawater disturbance simulation system.

[0072] The temperature control module includes a constant temperature water bath system, a constant temperature water bath jacket, a temperature sensor 408, and a pressure sensor. The constant temperature water bath system includes a water bath tank 301, a circulation pump, and circulation pipelines. The constant temperature medium is transported to the constant temperature water bath jacket and returned to the water bath tank 301 under circulation, forming a closed loop to regulate the temperature of the reaction chamber 203. The constant temperature water bath jacket includes a first constant temperature water bath jacket 302 and a second constant temperature water bath jacket 303. The first constant temperature water bath jacket 302 is wrapped around the reaction chamber, and the second constant temperature water bath jacket 303 is used to regulate the pressure chamber assembly.

[0073] The data detected by temperature sensor 408, pressure sensor 405, and pressure sensor 414 are output to the computer through a data acquisition unit. The computer can then synchronously acquire, display, and store multiple parameters such as temperature and pressure.

[0074] The multimodal synchronous monitoring module includes a particle image velocimetry (PIV) system and an acoustic monitoring unit. The PIV system includes a light source 413, a camera 412, a laser, and a control unit. The camera 412, light source 413, and laser face a transparent viewing window. The light source, camera, and laser are each connected to the control unit, which is electrically connected to a computer. The light source 413 and camera 412 are used to acquire visual images of the bubble plume. Existing technology can be used for the PIV system.

[0075] The acoustic monitoring unit includes a first acoustic probe 409 and a second acoustic probe 411, which are used to collect acoustic scattering / echo signals of the bubble plume.

[0076] All of the above monitoring modules are connected to computer 401 to achieve time-synchronized acquisition and storage of multi-source data.

[0077] Specifically, the key parts of the device in this invention that come into contact with gas and liquid are all designed with a sealed structure to ensure the stability and safety of the system under pressure variation and disturbance conditions. The reaction chamber body is a closed pressure-bearing structure, and its top interface, side wall disturbance interface and bottom connection are all equipped with sealing rings or sealing gaskets to prevent gas or liquid leakage.

[0078] Specifically, a pressure-resistant sealing ring is provided between the movable component between the lower and upper pressure regulating chambers and the channel wall to maintain the sealing of the chamber during the movement of the push rod and the opening and closing of the channel.

[0079] Preferably, the flexible membrane is sealed to the top structure of the reaction chamber, which isolates the gas from the fluid inside the reaction chamber while transmitting pressure. This sealing design ensures that the device maintains good sealing performance and operational stability during pressure regulation, gas evolution, and seawater disturbance experiments.

[0080] This invention also provides an experimental method for simulating the evolution of bubble plumes in cold seep areas under seawater disturbance, specifically including the following steps:

[0081] S1. Install the apparatus, perform experimental system initialization and sealing checks, and prepare for liquid injection and gas supply.

[0082] Before the experiment begins, the airtightness of the reaction chamber 203, the lower pressure regulating chamber 104, the upper pressure regulating chamber 114, and all connecting pipelines (gas supply pipeline, connecting channel, and disturbance water channel) is checked. The focus is on checking for leaks at the sealing point between the air chamber 206 at the top of the reaction chamber 203 and the flexible membrane 207, as well as at the sealing rings 113 / sealing gaskets at each interface and valve connections. After confirming that there are no leaks, the connecting channel between the lower pressure regulating chamber 104 and the upper pressure regulating chamber 114 is closed, so that the lower pressure regulating chamber 104 is in a sealed state. The constant temperature water bath system is then started, so that the constant temperature medium enters the constant temperature water bath jacket covering the outside of the reaction chamber 203 through the circulation pump and forms a reflux closed circulation to stabilize the system temperature to the set value. The constant temperature water bath jacket includes a first constant temperature water bath jacket 302 and a second constant temperature water bath jacket 303, and the water bath of the constant temperature water bath system is a water bath tank 301. Subsequently, deionized water or artificial seawater is injected into the reaction chamber 203 to maintain a stable liquid level; experimental water is injected into the lower pressure regulating chamber 104 to complete the filling and venting process. Then, the gas tank 101 is opened, and high-pressure methane gas is slowly introduced through the first electrically controlled valve 402. After the methane gas is stabilized by the buffer container 102, it enters the gas supply pipeline and is filled into the lower pressure regulating chamber 104 according to the set operating conditions to establish a dissolved methane system under controllable temperature and pressure conditions, providing a gas source for subsequent gas evolution and bubble plume generation.

[0083] S2. The device operates, generating bubbles:

[0084] After establishing the S1 dissolved methane system, the dual-cylinder pump 109 is started to drive the piston 106 in reciprocating motion. Under sealed conditions, this changes the effective volume of the pressure regulating chamber 104, thereby controlling the pressure within the chamber. By setting the displacement amplitude, movement speed, and action time of the piston 106, the pressure within the pressure regulating chamber 104 undergoes a step or gradual change. When the pressure decreases to the point where the dissolution equilibrium condition changes, dissolved methane is induced to precipitate from the dissolved state to the free state, forming a bubble-water mixture. The pressure sensor 405 monitors the pressure within the pressure regulating chamber 104 in real time and feeds the pressure signal back to the PLC controller 112 to ensure the stability and repeatability of the bubble generation process.

[0085] S3, Bubble Stream Injection and Cold Seep Channel Mode Control:

[0086] After the S2 bubble generation is completed, the PLC controller 112 continuously receives the pressure signal of the lower pressure regulating chamber 104 collected by the first pressure sensor 405 and makes real-time judgments. When the pressure in the lower pressure regulating chamber 104 reaches the preset threshold, the PLC controller 112 automatically outputs a control command to drive the solenoid reversing valve 111 to switch the hydraulic oil flow direction, causing the hydraulic cylinder 105 to move and drive the push rod 103 to retract, thereby automatically opening the communication channel between the lower pressure regulating chamber 104 and the upper pressure regulating chamber 114. After the channel is opened, the bubble-water mixture formed in the lower pressure regulating chamber 104 enters the upper pressure regulating chamber 114 under the action of pressure difference, and is further automatically injected into the reaction chamber 203 through the communication channel, forming a methane bubble plume in the reaction chamber 203.

[0087] By pre-setting the pressure threshold, channel opening duration, and opening-closing sequence in the PLC controller 112, the PLC controller 112 can automatically start, maintain, and shut down the bubble plume injection process, thereby constructing a continuous or intermittent release cold spring channel working mode; the entire process requires no manual intervention, ensuring the stability, repeatability, and controllability of the bubble plume injection condition.

[0088] S4. Application of seawater disturbance and construction of DC disturbance flow field:

[0089] After the S3 bubble plume injection is completed and the internal pressure of the reaction chamber 203 is stabilized under the action of the reaction chamber pressure boundary adjustment module, experimental water is injected into the water tank and the diversion pipeline is opened, allowing the water to enter the disturbance interface on the side wall of the reaction chamber 203 under the action of the pump 208. The water tank includes water tank A 201 and water tank B 202. Before entering the reaction chamber 203 through the diversion pipeline, the disturbed water is rectified by passing through the orifice plate assembly set at the disturbance interface. The orifice plate assembly includes orifice plate A 204 and orifice plate B 205, which transforms the water flow entering the reaction chamber 203 from the original unstable flow state into a stable lateral flow with uniform velocity distribution and small pulsations, thereby constructing an approximately direct-flow seawater disturbance flow field within the reaction chamber 203.

[0090] By adjusting the liquid levels in tanks A 201 and B 202, the flow rate in the guide pipes, and the aperture and opening ratio of orifice plates A 204 and B 205, the intensity and velocity distribution of the disturbance flow can be changed, thus constructing different disturbance conditions without altering the overall pressure conditions of the reaction chamber 203. The resulting DC disturbance flow field interacts with the bubble plume within the reaction chamber 203, and is used to study the evolution characteristics of methane bubble plumes under seawater disturbance conditions.

[0091] S5. Multimodal synchronous monitoring:

[0092] After completing the construction of the S4 DC-type seawater disturbance flow field, a multimodal monitoring system was simultaneously activated to observe and acquire data on the evolution of the methane bubble plume within the reaction chamber. Image sequences of the bubble plume were acquired using a camera, and the images were segmented and feature extracted to obtain the bubble projected area, contour morphology, number density, and spatial distribution. A particle image velocimetry (PIV) system measured the velocity distribution of the flow field within the reaction chamber and the motion characteristics of the bubble swarm. Simultaneously, acoustic monitoring units installed inside or on the chamber walls collected acoustic scattering or echo signals generated by the bubble plume. The acoustic monitoring units included a first acoustic probe 409 and a second acoustic probe 411.

[0093] S6. Calculate the overall flux of the plume (methane flux): Measure the velocity distribution of the continuous phase flow field using a particle image velocimetry (PIV) system, and combine this with bubble image tracking / cross-correlation calculations to obtain the instantaneous velocity and trajectory of the bubble swarm, thus obtaining the bubble velocity. Simultaneously, acoustic scattering / echo signals of the plume are collected using acoustic monitoring units deployed inside or on the bulkhead of the reaction chamber, and the echo amplitude is extracted. and correlate it with the bubble volume fraction Correlation calibration is performed to establish acoustic amplitude. With bubble volume fraction The quantitative mapping relationship between them. The above PIV and acoustic data are uniformly transmitted to the computer to realize the time-synchronous acquisition, fusion processing and storage of multi-source data.

[0094] Among them, bubble velocity It can be represented as:

[0095] (1)

[0096] in, This refers to the centroid position of the same bubble in two adjacent frames (after converting pixels to physical scale). Let z be the time interval between the two particles, z be the height of the center of mass, and t be the time.

[0097] bubble volume fraction It can be represented as:

[0098] (2)

[0099] Where r is the distance from the transducer to the sampling body, β is the medium absorption coefficient (or equivalent attenuation coefficient), and k is the empirical calibration coefficient.

[0100] Based on the above parameters, the methane bubble flux can be calculated. Methane bubble volume flux. It can be represented as:

[0101] (3)

[0102] in, The volume fraction of bubbles obtained from acoustic signal inversion. Let A be the average rising velocity of the bubble swarm and A be the cross-sectional area of ​​the plume. Under known gas density conditions, the methane mass flux can be further obtained. Through collaborative analysis of multimodal data, a comprehensive characterization of the methane bubble plume morphology, flow field structure, and methane flux variation characteristics under seawater disturbance conditions can be achieved.

[0103] The embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A simulation device for the evolution of bubble plumes in a cold seep area under seawater disturbance, characterized in that, include: The reaction chamber is equipped with a transparent viewing window; The gas-evolving bubble module is connected to the lower part of the reaction chamber to create a supersaturated environment for dissolved methane and induce the dissolved methane to precipitate and form a bubble plume through pressure control, which is used to provide a bubble plume source for the reaction chamber. The chamber pressure regulation module is connected to the upper part of the reaction chamber and is used to stabilize the internal pressure environment of the reaction chamber. The seawater disturbance coupling module is connected to the side of the reaction chamber and is used to construct a controllable seawater disturbance flow field inside the reaction chamber. Temperature control module, used for temperature control of gas evolution bubble module and reaction chamber; The multimodal synchronous monitoring module includes a particle image velocimetry system and an acoustic monitoring unit. The acoustic monitoring unit is installed inside the reaction chamber, and the particle image velocimetry system is aimed at the transparent window of the reaction chamber. The computer is electrically connected to the gas evolution bubble module, the chamber pressure regulation module, the seawater disturbance coupling module, the temperature control module, and the multimodal synchronous monitoring module, respectively.

2. The simulation device for the evolution of bubble plumes in cold seep areas under seawater disturbance as described in claim 1, characterized in that, The gas-evolving bubble module includes a gas source, a pressure regulating chamber assembly, and a pressure sensor. The pressure regulating chamber assembly includes an upper pressure regulating chamber and a lower pressure regulating chamber, with a connecting channel between the upper and lower pressure regulating chambers. A push rod assembly is also provided on the connecting channel. The connecting channel can be opened or closed by retracting or extending the push rod assembly. A piston is movably connected to the bottom of the lower pressure regulating chamber. The volume of the lower pressure regulating chamber can be changed by the movement of the piston. The air source is connected to the lower pressure regulating chamber; pressure sensor number one is located inside the lower pressure regulating chamber.

3. The simulation device for the evolution of bubble plumes in cold seep areas under seawater disturbance according to claim 2, characterized in that, The chamber pressure regulation module includes an air chamber, a flexible membrane, and a second pressure sensor located at the top of the reaction chamber. The air chamber is connected to an air source via an air supply pipeline and is used to apply external pressure to one side of the flexible membrane. The flexible membrane is located between the air chamber and the fluid inside the reaction chamber, and its lower part is in direct contact with the liquid inside the reaction chamber, used to transmit the pressure of the air chamber to the inside of the reaction chamber. The second pressure sensor is used to monitor the pressure changes inside the air chamber in real time.

4. The simulation device for the evolution of bubble plumes in cold seep areas under seawater disturbance according to claim 3, characterized in that, The flexible membrane is arranged at an angle.

5. The simulation device for the evolution of bubble plumes in cold seep areas under seawater disturbance according to claim 1, characterized in that, The seawater disturbance coupling module includes a water tank, a flow guide pipe, a valve assembly, and an orifice plate assembly; a disturbance interface is provided on the side wall of the reaction chamber, and the water tank is connected to the disturbance interface through the flow guide pipe to provide disturbed water to the reaction chamber. A valve assembly is provided on the flow guide pipe, and the orifice plate assembly is located between the flow guide pipe and the reaction chamber.

6. The simulation device for the evolution of bubble plumes in cold seep areas under seawater disturbance according to claim 1, characterized in that, The temperature control module includes a constant temperature water bath system, a constant temperature water bath jacket, and a temperature sensor. The constant temperature water bath system includes a constant temperature water bath tank, a heating unit, a circulation pump, and circulation pipelines. The constant temperature water bath tank is connected to the circulation pipelines, the circulation pipelines are connected to the circulation pump, and the heating unit is connected to the circulation pipelines. The constant temperature medium is transported to the constant temperature water bath jacket by the circulation pump and returned to the water bath tank via the return pipeline. There are two constant temperature water bath jackets, which are respectively wrapped around the reaction chamber and the regulating pressure chamber assembly.

7. The simulation device for the evolution of bubble plumes in cold seep areas under seawater disturbance according to claim 1, characterized in that, The particle image velocimetry system includes a light source, a camera, a laser, and a control unit. The camera, light source, and laser are opposite to a transparent viewing window. The light source, camera, and laser are each connected to the control unit, which is electrically connected to a computer.

8. An experimental method for simulating the evolution of bubble plumes in cold seep areas under seawater disturbance, characterized in that, The simulation device for simulating the evolution of bubble plumes in cold seeps under seawater disturbance as described in any one of claims 1 to 7 includes the following steps: S1. Device installation; S2. The device operates and generates bubbles: The piston of the gas evolution bubble module reciprocates, changing the effective volume of the pressure regulating chamber of the gas evolution bubble module under sealed conditions, thereby controlling the pressure inside the chamber and causing the pressure inside the pressure regulating chamber to change stepwise or slowly. When the pressure drops to the point where the dissolution equilibrium condition changes, it induces dissolved methane to precipitate from the dissolved state to the free state, forming a bubble-water mixture. S3. Bubble Stream Injection and Cold Seep Channel Mode Control: When the pressure in the lower regulating chamber reaches the preset threshold, the push rod of the gas-evolving bubble module retracts, the lower regulating chamber connects with the upper regulating chamber, and the bubble-water mixture formed in the lower regulating chamber enters the upper regulating chamber under the action of pressure difference to form a cold seep channel mode, and is further automatically injected into the reaction chamber through the connecting channel to form a methane bubble stream in the reaction chamber. S4. Application of seawater disturbance and construction of DC disturbance flow field: After completing the injection of bubble plume in S3 and stabilizing the internal pressure of the reaction chamber under the action of the chamber pressure regulation module, experimental water is injected into the water tank of the seawater disturbance coupling module and the flow guide pipe is opened. The water enters the disturbance interface on the side wall of the reaction chamber under the action of the pump. Before the disturbed water enters the reaction chamber through the flow guide pipe, it is rectified by the orifice plate assembly set at the disturbance interface. The water flow entering the reaction chamber is transformed from the original unstable flow state into a stable lateral flow with uniform velocity distribution and small pulsation, thereby constructing an approximately DC seawater disturbance flow field in the reaction chamber. S5. Multimodal Synchronous Monitoring: After completing the construction of the S4 DC-type seawater disturbance flow field, the multimodal monitoring system is activated to synchronously observe and acquire data on the evolution of the methane bubble plume in the reaction chamber. The particle image velocimetry system is used to acquire image sequences of the bubble plume, and the images are segmented and feature extracted to obtain the bubble projected area, contour morphology, bubble number density and spatial distribution, and to measure the velocity distribution of the flow field in the reaction chamber and the motion characteristics of the bubble swarm. At the same time, the acoustic monitoring unit is used to collect the acoustic scattering or echo signals generated by the bubble plume. The above particle image velocimetry and acoustic data are transmitted to the computer to realize the time-synchronous acquisition, fusion processing and storage of multi-source data.

9. The experimental method for coupling methane bubble plume and seawater disturbance in a cold seep environment according to claim 8, characterized in that, It also includes step S6, Calculating the overall flux of the plume: The velocity distribution of the continuous phase flow field is measured using a particle image velocimetry system, and the instantaneous velocity and trajectory of the bubble swarm are obtained by combining bubble image tracking / cross-correlation calculations, thus yielding the bubble velocity. Simultaneously, acoustic scattering / echo signals of the plume are collected using acoustic monitoring units deployed inside or on the bulkhead of the reaction chamber, and the echo amplitude is extracted. and correlate it with the bubble volume fraction Perform correlation calibration to establish acoustic amplitude. With bubble volume fraction The quantitative mapping relationship between them Bubble speed Represented as: in, The centroid positions of the same bubble in two adjacent frames. Let z be the time interval between the two particles, z be the height of the center of mass, and t be the time. bubble volume fraction Represented as: Where r is the distance from the transducer to the sampling volume, β is the medium absorption coefficient, and k is the empirical calibration coefficient, the echo amplitude is extracted. ; methane bubble volume flux Represented as: in, The volume fraction of bubbles obtained from acoustic signal inversion. Let A be the average rising velocity of the bubble swarm, and let A be the cross-sectional area of ​​the plume.

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