CN-122016233-A - Device and method for simulating bubble plume evolution in cold spring area under sea water disturbance

CN122016233ACN 122016233 ACN122016233 ACN 122016233ACN-122016233-A

Abstract

The invention provides a device and a method for simulating bubble plume evolution in a cold spring area under sea water disturbance, which realize multi-physical-field joint regulation and control of bubble release and movement process through the collaborative design of gassing type bubble generation, pressure modulation control and lateral disturbance application, wherein the device comprises a reaction cabin, a gassing type bubble module, a cabin pressure regulation module, a sea water disturbance coupling module, a temperature control module and a multi-mode synchronous monitoring module; the multimode synchronous monitoring module comprises a particle image velocimetry system and an acoustic monitoring unit, wherein the acoustic monitoring unit is arranged in a reaction cabin, the particle image velocimetry system is aligned to a transparent window of the reaction cabin, and the acoustic monitoring unit is combined with a Particle Image Velocimetry (PIV) observation result to form a PIV-acoustic dual observation system so as to realize synchronous acquisition of bubble plume form evolution, flow field structural change and methane flux response characteristics.

Inventors

DONG LIN
WAN YIZHAO
WU NENGYOU
LI YANLONG
LI MENG
QI MINHUI
HUANG LI

Assignees

崂山国家实验室

Dates

Publication Date: 20260512
Application Date: 20260210

Claims (9)

1. Cold spring district bubble plume evolution analogue means under sea water disturbance, its characterized in that includes: The reaction cabin is provided with a transparent window; The gas-separating type bubble module is connected to the lower part of the reaction cabin, constructs a dissolved methane supersaturated environment, and induces the dissolved methane to separate out through pressure control to form a bubble plume, so as to provide a bubble plume source for the reaction cabin; The cabin pressure adjusting module is connected to the upper part of the reaction cabin and used for stabilizing the internal pressure environment of the reaction cabin; the seawater disturbance coupling module is connected to the side part of the reaction cabin and used for constructing a controllable seawater disturbance flow field in the reaction cabin; the temperature control module is used for controlling the temperature of the gassing type bubble module and the reaction cabin; The multimode synchronous monitoring module comprises a particle image velocimetry system and an acoustic monitoring unit, wherein the acoustic monitoring unit is arranged in the reaction chamber, and the particle image velocimetry system is aligned to a transparent window of the reaction chamber; And the computer is electrically connected with the gassing type bubble module, the cabin pressure adjusting module, the seawater disturbance coupling module, the temperature control module and the multi-mode synchronous monitoring module respectively.
2. The device for simulating the evolution of a plume of bubbles in a cold spring area under seawater turbulence as claimed in claim 1, wherein the gassing type bubble module comprises a gas source, a pressure regulating cavity assembly and a first pressure sensor; The pressure regulating cavity assembly comprises an upper pressure regulating cavity and a lower pressure regulating cavity, a communication channel is arranged between the upper pressure regulating cavity and the lower pressure regulating cavity, a push rod assembly is further arranged on the communication channel, the push rod assembly is retracted or extended to realize the opening or closing of the communication channel, a piston is movably connected to the bottom of the lower pressure regulating cavity, and the volume of the lower pressure regulating cavity is changed through the movement of the piston; the first pressure sensor is arranged in the lower pressure regulating cavity.
3. The device for simulating bubble plume evolution in a cold spring area under sea water disturbance according to claim 2, wherein the cabin pressure regulating module comprises an air cavity, a flexible membrane and a second pressure sensor, wherein the air cavity is arranged at the top of the reaction cabin and is communicated with an air source through an air supply pipeline and used for applying external pressure to one side of the flexible membrane, the flexible membrane is arranged between the air cavity and fluid in the reaction cabin, the lower part of the flexible membrane is directly contacted with liquid in the reaction cabin and used for transmitting the pressure of the air cavity to the interior of the reaction cabin, and the second pressure sensor is used for monitoring pressure change in the air cavity in real time.
4. The device for simulating bubble plume evolution in a cold spring zone under seawater turbulence according to claim 3, wherein the flexible membrane is arranged in an inclined arrangement.
5. The device for simulating bubble plume evolution in a cold spring area under sea water disturbance according to claim 1, wherein the sea water disturbance coupling module comprises a water tank, a diversion pipeline, a valve assembly and an orifice assembly, a disturbance interface is arranged on the side wall of the reaction cabin, the water tank is connected with the disturbance interface through the diversion pipeline and is used for providing disturbance water for the reaction cabin, the valve assembly is arranged on the diversion pipeline, and the orifice assembly is arranged between the diversion pipeline and the reaction cabin.
6. The device for simulating bubble plume evolution in a cold spring area under sea water disturbance according to claim 1, wherein the temperature control module comprises a constant-temperature water bath system, a constant-temperature water bath jacket and a temperature sensor, the constant-temperature water bath system comprises a constant-temperature water bath tank, a heating unit, a circulating pump and a circulating pipeline, the constant-temperature water bath tank is connected with the circulating pipeline, the circulating pipeline is connected with the circulating pump, a constant-temperature medium is conveyed to the constant-temperature water bath jacket through the circulating pump and returns to the water bath tank through a return pipeline, and the constant-temperature water bath jacket is respectively wrapped outside the reaction cabin and the pressure regulating cavity assembly.
7. The device for simulating bubble plume evolution in cold spring zone under sea water disturbance according to claim 1, wherein the particle image velocimetry system comprises a light source, a camera, a laser and a control part, wherein the camera, the light source and the laser are opposite to the transparent window, the light source, the camera and the laser are respectively connected with the control part, and the control part is electrically and mechanically connected with the computer.
8. The experimental method of the cold spring zone bubble plume evolution simulation device under seawater disturbance is characterized by comprising the following steps of: s1, installing a device; S2, the device operates to generate bubbles, namely, a piston of the gassing type bubble module reciprocates, the effective volume of a lower pressure regulating cavity of the gassing type bubble module is changed under a sealing condition, so that the pressure in the cavity is controllably regulated, the pressure in the lower pressure regulating cavity is subjected to step change or gradual change, and when the pressure is reduced to the dissolution balance condition, dissolved methane is induced to be separated from a dissolution state to a free state, so that a bubble-water mixture is formed; s3, injecting bubbles and controlling a cold spring channel mode, namely when the pressure of the lower pressure regulating cavity reaches a preset threshold value, retracting a push rod of the gassing type bubble module, communicating the lower pressure regulating cavity with the upper pressure regulating cavity, enabling bubbles-water mixture formed in the lower pressure regulating cavity to enter the upper pressure regulating cavity under the action of pressure difference to form the cold spring channel mode, and further automatically injecting the bubbles-water mixture into the reaction cabin through the connecting channel to form methane bubbles and plumes in the reaction cabin; S4, after S3 bubble plume injection is completed and the internal pressure of the reaction chamber is kept stable under the action of the chamber pressure adjusting module, experimental water is injected into a water tank of the seawater disturbance coupling module and a diversion pipeline is started, so that water enters a disturbance interface on the side wall of the reaction chamber under the action of a pump, and the disturbance water sequentially passes through an orifice plate assembly arranged at the disturbance interface to carry out rectification treatment before entering the reaction chamber through the diversion pipeline, so that the water flow entering the reaction chamber is converted into stable lateral incoming flow with uniform speed distribution and smaller pulsation from the original unstable flow state, and a seawater disturbance flow field similar to direct current is constructed in the reaction chamber; S5, multi-mode synchronous monitoring, namely starting a multi-mode monitoring system after the construction of the S4 direct-current sea water disturbance flow field is completed, synchronously observing and acquiring data of the evolution process of the methane bubble plume in the reaction cabin, acquiring an image sequence of the bubble plume by utilizing a particle image velocimetry system, segmenting and extracting the image to obtain a bubble projection area, a profile form, a bubble quantity density and spatial distribution thereof, measuring flow field speed distribution in the reaction cabin and motion characteristics of a bubble group, acquiring acoustic scattering or echo signals generated by the bubble plume by utilizing an acoustic monitoring unit, and transmitting the particle image velocimetry and acoustic data to a computer to realize time synchronous acquisition, fusion processing and storage of multi-source data.
9. The method for methane bubble plume-seawater disturbance coupling experiment under cold spring environment according to claim 8, further comprising step S6, Calculating the integral flux of plume, namely measuring the velocity distribution of a continuous phase flow field by using a particle image velocimetry system, and obtaining the instantaneous velocity and the motion trail of a bubble group by combining with bubble image tracking/cross-correlation calculation so as to obtain the velocity of the bubble At the same time, acoustic scattering/echo signals of plumes are collected by using acoustic monitoring units arranged in the reaction cabin or at the cabin wall to extract echo amplitude And mixing it with the volume fraction of bubbles Performing correlation calibration to establish acoustic amplitude With bubble volume fraction The quantitative mapping relation between the two components, Bubble velocity Expressed as: Wherein, the Is the centroid position of the same bubble in two adjacent frames, For the time interval between two particles, z is the height of the centroid and t is time; Volume fraction of bubbles Expressed as: wherein r is the distance from the transducer to the sampling body, beta is the medium absorption coefficient, k is the empirical calibration coefficient, and the echo amplitude is extracted ; Methane bubble volume flux Expressed as: Wherein, the For the volume fraction of bubbles derived from the acoustic signal inversion, The average rising velocity of the bubble group is represented by a, which is the plume cross-sectional area.

Description

Device and method for simulating bubble plume evolution in cold spring area under sea water disturbance Technical Field The invention relates to the technical field of ocean cold spring simulation and multiphase flow experiment devices, in particular to a cold spring area bubble plume evolution simulation device and method under seawater disturbance, which are used for methane bubble plume-seawater disturbance coupling experiments under a cold spring environment. Background In deep sea cold spring systems, after methane enters the water body in a bubble state, the subsequent migration and diffusion processes are not only determined by the buoyancy kinetics of the bubbles themselves, but also the surrounding seawater flow conditions play a key modulating role. In an actual marine environment, a cold spring area is often overlapped with a background ocean current, a tidal current, an internal wave disturbance, a local shear flow and other multi-scale sea water movement processes, so that a bubble plume generally presents obvious deflection, swing, diffusion and non-axisymmetric evolution characteristics in the rising process. The sea water disturbance not only changes the space shape and the ascending path of the plume of the bubbles, but also can obviously influence the residence time, the coalescence and breaking behavior and the induced flow field structure of the bubbles, thereby further controlling the transportation efficiency and the environmental effect of methane in the water body. Unlike ideal bubble plume with similar axial symmetry under still water condition, cold spring plume under the action of ocean current or disturbance flow field is in complex forms of inclined rising, serpentine swing or intermittent bifurcation, and the macroscopic structure and local dynamics characteristics are highly dependent on the magnitude, direction and time variation characteristics of the external flow velocity. The geometry of the plume, the angle of deflection of the axis and its evolution with altitude have therefore been considered as important information carriers reflecting the local seawater flow conditions in the cold spring zone. However, because of the harsh deep sea environment conditions, the realization of the fine observation of the cold spring plume and sea water disturbance coupling process directly in situ still faces a great technical challenge, so that the research is generally carried out by adopting an experimental simulation mode. However, existing experimental studies still have certain limitations. Most researches adopt modes of air source leakage, hydrate decomposition or manual injection and the like to generate bubble plumes, and although a large amount of bubble observation data is accumulated, the bubble release rate is usually more severe, the stronger flow field disturbance is accompanied, the randomness of the bubble size and the generation frequency is larger, and the synchronous and accurate observation of the bubble form, the hydrate generation process and the flow field structure is difficult to realize in the same experimental system. For example, chinese patent publication No. CN117672065B proposes a submarine bubble plume imaging simulation platform and simulation method, which ejects gas and water flow simultaneously, so that bubble generation is in an artificially set flow field, which cannot reflect the evolution process of naturally generated bubbles, and is difficult to be applied to cold spring environment. For another example, the patent of China patent publication No. CN120740873B provides an acousto-optic fusion cold spring methane detection method, system, device and storage medium, mainly adopts sonar and an underwater high-speed camera to carry out acoustic and optical imaging observation on the bubble plume, focuses on target identification and morphology recording, and has limited quantitative detection capability on a flow field structure and bubble movement. The Chinese patent with publication number CN102331511B discloses a high-frequency image acquisition and flow field visualization method based on Particle Image Velocimetry (PIV), which can realize the measurement of a fluid velocity field, but the method is mainly designed for a single-phase or weak two-phase flow field, and does not combine methane bubble generation and hydrate shell evolution process in cold spring environment to carry out system layout, so that the coupling characteristic identification of bubble dynamics behavior and phase change process is difficult to realize. In addition, when PIV technology is directly applied in a gas-liquid two-phase system, the strong reflection on the surface of bubbles and the unstable release process of the strong reflection easily cause interference on imaging quality, so that local velocity vector fluctuation is obvious. Therefore, an experimental device capable of stably constructing methane bubble plumes under the condition of controllable pressure and