Oil pipe leakage flow field observation experiment system

Abstract

The invention discloses an oil pipe leakage flow field observation experiment system which comprises a jacket structure assembly, a schlieren assembly and a fluid supply assembly. The jacket structure assembly comprises a sleeve and an oil pipe which are coaxially sleeved, a detachable leakage connector is arranged on the side wall of the oil pipe, and a leakage channel communicating the inside and the outside of the oil pipe is arranged in the connector. The schlieren assembly adopts a Z-shaped light path design and comprises a point light source assembly, a first reflector assembly, a second reflector assembly, a light cutting assembly and a high-speed camera assembly which are arranged in sequence, and a parallel light path is formed between the two reflector assemblies. The jacket structure assembly is arranged in a parallel light path, so that the axis of the oil pipe is parallel to the light path. The leakage joint is connected with the fluid supply assembly for experiment, parallel light passes through the oil pipe and is focused and imaged through reflection, and light refraction errors are eliminated. The system avoids light deflection of the casing wall through axial observation, obtains a distortionless clear schlieren image, accurately analyzes the form of leaked fluid and the characteristics of a flow field, and provides high-precision data support for oil pipe leakage detection.

Description

Technical Field

[0001] The present invention relates to the technical field of oil and gas development, and particularly relates to an observation experimental system for the flow field of tubing leakage. Background Art

[0002] As the global oil and gas resource development gradually expands towards low-permeability and tight reservoirs, gas flooding tertiary oil recovery technology has become one of the key means to improve the recovery rate. During the process of using injection media such as carbon dioxide and hydrocarbon gases, the downhole tubing string system is under the action of high pressure and corrosive media for a long time, resulting in leakage prone to occur at key parts such as tubing hangers and packers. Such leakage will not only reduce the efficiency of the recovery system, but also bring serious environmental risks. Traditional leakage detection methods based on pressure monitoring have significant deficiencies in accurately locating the leakage position, while conventional downhole detection methods are difficult to meet the actual requirements in terms of leakage detection efficiency and accuracy due to complex installation, long cycle, and high consumption of manpower and material resources. Therefore, there is an urgent need to develop new downhole leakage detection methods and devices.

[0003] The key to developing these new detection methods and devices lies in accurately analyzing the morphology of the leaked fluid and the flow field characteristics, so as to provide high-precision data support for tubing leakage detection. For this reason, it is necessary to develop an indoor simulation experimental system for observing the flow field of downhole tubing leakage and conduct high-precision flow field analysis to meet the requirements of downhole tubing leakage detection and improve the accuracy and reliability of detection technology.

[0004] In recent years, optical flow field observation technology has made remarkable progress in the field of leakage detection. Background schlieren technology (BOS) realizes flow field visualization by analyzing the refractive index change caused by the fluid density gradient, and has the advantage of a large field of view compared with traditional schlieren technology. However, experimental studies show that the resolution of the BOS system is less than 0.5 mm under the leakage rate condition of 10 m³ / d, and the sensitivity threshold is only 2.5×10⁻³ g / cm³, making it difficult to capture the flow field characteristics in the initial stage of micro-leakage. To improve the accuracy, the industry has successively developed a single-mirror off-axis optical path and a single-mirror coaxial optical path system. Although the former simplifies the optical path structure, it will generate about 15% image ghost interference; the latter eliminates the ghost through a beam splitter, but the light source utilization rate is reduced to 38%, and about 20% additional optical distortion is introduced.

[0005] The emergence of the double-mirror Z-shaped optical path technology significantly improves the above defects. It uses symmetrically arranged concave mirrors to form a parallel optical path, improving the collimation of light in the test area and the schlieren sensitivity. However, most of the existing implementation schemes adopt the lateral observation mode. When simulating the downhole annulus environment, the circular pipe wall produces a Fresnel refraction deviation of about 2.8° for the parallel light, resulting in barrel distortion of the flow field image, and the maximum distortion amount can reach 12%, seriously affecting the quantitative analysis of the leakage ejection angle and vortex structure. Summary of the Invention

[0006] The present invention aims to solve at least one of the technical problems existing in the prior art. For this purpose, the present invention provides an experimental system for observing the flow field of oil pipe leakage, aiming to solve the problem that in the related art, the double-mirror Z-shaped optical path technology adopts a lateral observation mode, resulting in refraction of parallel light by the circular pipe wall, and further causing distortion of the flow field image.

[0007] The present invention provides an experimental system for observing the flow field of oil pipe leakage, comprising: A jacket structure assembly, including a bracket, a sleeve and an oil pipe. The sleeve and the oil pipe are both connected to the bracket. The oil pipe is coaxially arranged with the sleeve, and the oil pipe is arranged inside the sleeve. A leakage joint is provided on the side wall of the oil pipe, and the leakage joint is detachably connected to the oil pipe. A leakage channel is provided inside the leakage joint, and the leakage channel communicates with the inside and outside of the oil pipe. A schlieren assembly, including a point light source assembly, a first mirror assembly, a second mirror assembly, a light chopping assembly and a high-speed camera assembly arranged in sequence along a Z-shaped optical path. The first mirror assembly is used to emit the light emitted by the point light source assembly in a direction parallel to the axis of the oil pipe towards the oil pipe. The second mirror assembly is used to receive and focus the reflected light passing through the oil pipe to the light chopping assembly. The high-speed camera is used to receive the light passing through the light chopping assembly. A fluid supply assembly, the fluid outlet end of the fluid supply assembly is detachably connected to one end of the leakage joint located inside the oil pipe, and the fluid supply assembly communicates with the leakage channel.

[0008] According to the experimental system for observing the flow field of oil pipe leakage provided by the present invention, the length of the oil pipe is greater than the length of the sleeve. Both ends of the oil pipe extend outside the sleeve. The bracket includes a first support frame and a second support frame. The first support frame supports the bottom of the sleeve, and the second support frame supports the bottom of the part of the oil pipe extending outside the sleeve.

[0009] According to the experimental system for observing the flow field of oil pipe leakage provided by the present invention, when the sleeve is connected to the first support frame and the oil pipe is connected to the second support frame, the axes of the sleeve and the oil pipe are located in the same vertical plane, and at least one of the first support frame and the second support frame is provided with a first height adjustment mechanism.

[0010] According to the experimental system for observing the flow field of oil pipe leakage provided by the present invention, the leakage joint includes: A first joint, one end of the first joint is located inside the oil pipe and is used for detachably connecting to the fluid supply assembly, and the other end of the first joint passes through the oil pipe; A second joint, which is detachably connected to one end of the first joint located outside the oil pipe; The leakage channel includes a through hole provided on the first joint and a leakage hole provided on the second joint, and the through hole communicates with the leakage hole.

[0011] According to the oil pipe leakage flow field observation experimental system provided by the present invention, the oil pipe includes: A pipe body, on which an operation window is provided at least at a position opposite to the leakage joint; A window cover, which is detachably connected to the pipe body and is used to close or open the operation window. After the window cover is connected to the pipe body, the combination forms a cylindrical structure.

[0012] According to the oil pipe leakage flow field observation experimental system provided by the present invention, the operation window extends along the axial direction of the pipe body from one end of the pipe body to a position close to the other end, and the area where the operation window is located covers the leakage joint. The window cover is an arc-shaped cover plate, and an axial limiting structure and a radial limiting structure are provided between the window cover and the pipe body.

[0013] According to the oil pipe leakage flow field observation experimental system provided by the present invention, both the first mirror assembly and the second mirror assembly include lenses and form adjustment mechanisms. The form adjustment mechanism at least includes a second height adjustment mechanism, a horizontal movement mechanism, a deflection adjustment mechanism, and a pitch adjustment mechanism.

[0014] According to the oil pipe leakage flow field observation experimental system provided by the present invention, the point light source assembly includes an LED point light source, a third height adjustment mechanism, and a first guide rail. The third height adjustment mechanism is provided at the bottom of the LED point light source, and the bottom of the third height adjustment mechanism is slidably connected to the first guide rail.

[0015] According to the oil pipe leakage flow field observation experimental system provided by the present invention, the light cutting assembly includes a light cutting device, a fourth height adjustment mechanism, and a second guide rail. The fourth height adjustment mechanism is provided at the bottom of the light cutting device, and the bottom of the fourth height adjustment mechanism is slidably connected to the second guide rail.

[0016] According to the oil pipe leakage flow field observation experimental system provided by the present invention, the high-speed camera assembly includes a high-speed camera and a fifth height adjustment mechanism. The fifth height adjustment mechanism is provided at the bottom of the high-speed camera.

[0017] Due to the adoption of the above technical solutions, the present invention has the following advantages: The oil pipe leakage flow field observation experimental system provided by the present invention includes a jacket structure assembly, a schlieren assembly, and a fluid supply assembly. The jacket structure assembly includes a bracket, a sleeve, and an oil pipe. The sleeve and the oil pipe are both connected to the bracket. The oil pipe is coaxially arranged with the sleeve, and the oil pipe is disposed inside the sleeve. A leakage joint is provided on the side wall of the oil pipe, and the leakage joint is detachably connected to the oil pipe. A leakage channel is provided inside the leakage joint, and the leakage channel communicates the inside and outside of the oil pipe. The schlieren assembly includes a point light source assembly, a first mirror assembly, a second mirror assembly, a light chopping assembly, and a high-speed camera assembly arranged in sequence along a Z-shaped optical path. During installation, the point light source assembly, the first mirror assembly, the second mirror assembly, the light chopping assembly, and the high-speed camera assembly are arranged along the Z-shaped optical path so that a parallel optical path can be formed between the first mirror assembly and the second mirror assembly. The jacket structure assembly is arranged between the first mirror assembly and the second mirror assembly, and the light can pass through the oil pipe, and the axis of the oil pipe is parallel to the optical path. Then, a leakage joint with the aperture of the leakage channel being the experimental aperture is selected and connected to the oil pipe. Finally, the fluid supply assembly is connected to one end of the leakage joint located inside the oil pipe. During the experiment, the first mirror assembly projects the light emitted by the point light source assembly in a direction parallel to the axis of the oil pipe onto the oil pipe. The second mirror assembly receives the light passing through the oil pipe and focuses and reflects the light to the light chopping assembly. The high-speed camera receives the light passing through the light chopping assembly. The oil pipe leakage flow field observation experimental system provided by the present invention forms a Z-shaped parallel optical path through double mirrors, making the oil pipe in the test area in parallel light, and the axis of the oil pipe is parallel to the light, avoiding the error caused by light refraction, so as to generate a clear and ghost-free schlieren image. This system simulates the change of the oil pipe leakage flow field and truly restores the physical field structure of the downhole oil pipe leakage. Through the observation in the axial direction, the deflection of the parallel light by the circular sleeve wall during side observation or radial observation is avoided, effectively avoiding the distortion of the schlieren image. The system can accurately determine the shape and flow field characteristics of the leaked fluid, provide scientific and effective data support for oil pipe leakage detection and treatment, improve the detection accuracy, and guide engineering practice. In addition, the structure of the present invention is reasonable, the operation is simple, and the experimental effect is good, which has important application value in the field of oil and gas engineering. Description of the Drawings

[0018] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0019] Figure 1 It is a schematic structural diagram of an oil pipe leakage flow field observation experimental system provided by an embodiment of the present invention; Figure 2It is the optical path diagram of the oil pipe leakage flow field observation experiment system provided by an embodiment of the present invention; Figure 3 It is the structural schematic diagram of the first mirror assembly or the second mirror assembly provided by an embodiment of the present invention; Figure 4 It is the structural schematic diagram of the point light source assembly provided by an embodiment of the present invention; Figure 5 It is the structural schematic diagram of the light chopping assembly and the high-speed camera assembly provided by an embodiment of the present invention; Figure 6 It is the structural schematic diagram of the jacket structure assembly provided by an embodiment of the present invention; Figure 7 It is the structural schematic diagram of the second support frame provided by an embodiment of the present invention; Figure 8 It is the connection structural schematic diagram of the oil pipe and the second support frame provided by an embodiment of the present invention; Figure 9 It is the exploded view of the first support frame provided by an embodiment of the present invention; Figure 10 It is the connection structural schematic diagram of the casing and the first support frame provided by an embodiment of the present invention; Figure 11 It is the exploded view of the oil pipe provided by an embodiment of the present invention; Figure 12 It is the structural schematic diagram of the first joint provided by an embodiment of the present invention; Figure 13 It is the structural schematic diagram of the second joint provided by an embodiment of the present invention; Figure 14 It is the result schematic diagram of observing the oil pipe leakage by using the oil pipe leakage flow field observation experiment system provided by an embodiment of the present invention.

[0020] Reference numerals: 110: Casing; 120: Tubing; 121: Pipe body; 122: Window cover; 123: Cover body; 124: First pin body; 125: Second pin body; 126: First pin hole; 127: Second pin hole; 210: Base plate; 220: L-shaped right-angle plate; 230: Arc bracket; 240: Upper arc clamp; 250: Lower arc clamp; 260: Fixed cylinder; 270: Adjusting rod; 300: Leakage joint; 310: First joint; 311: First hexagonal joint part; 312: Extended cylinder; 313: First threaded connection part; 314: Through hole; 320: Second joint; 321: Second hexagonal joint part; 322: Second threaded connection part; 323: Leakage hole; 410: Point light source assembly; 411: LED point light source; 412: Cooling fan; 413: Third height adjusting mechanism; 414: First guide rail; 420: First mirror assembly; 421: Lens; 422: Scissor arm lifting mechanism; 423: Horizontal moving mechanism; 424: Deflection adjusting mechanism; 425: Pitching adjusting mechanism; 430: Second mirror assembly; 440: Light cutting assembly; 441: Light cutting device; 442: Fourth height adjusting mechanism; 450: High-speed camera assembly; 451: High-speed camera; 452: Fifth height adjusting mechanism; 453: Second guide rail. Detailed implementation mode

[0021] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions in the present invention will be clearly and completely described below with reference to the accompanying drawings in the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present invention without making creative efforts shall fall within the protection scope of the present invention.

[0022] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. are based on the orientation or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention.

[0023] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "a plurality of" means two or more unless otherwise specifically defined.

[0024] In the present invention, unless otherwise clearly specified and defined, terms such as "mounted", "connected", "coupled", "fixed", etc. shall be construed in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0025] In the present invention, unless otherwise clearly specified and defined, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature may be that the first feature is directly above or obliquely above the second feature, or merely means that the first feature has a higher horizontal height than the second feature. The first feature being "under", "beneath" and "underneath" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely means that the first feature has a lower horizontal height than the second feature.

[0026] In the description of this specification, the description with reference to terms such as "an embodiment", "some embodiments", "example", "specific example", or "some examples", etc. means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms are not necessarily directed to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, without contradiction, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0027] The oil pipe leakage flow field observation experimental system provided by the present invention includes a jacket structure assembly, a schlieren assembly, and a fluid supply assembly. The jacket structure assembly includes a bracket, a casing, and an oil pipe. The casing and the oil pipe are both connected to the bracket. The oil pipe is coaxially arranged with the casing, and the oil pipe is arranged inside the casing. A leakage joint is provided on the side wall of the oil pipe, and the leakage joint is detachably connected to the oil pipe. A leakage channel is provided inside the leakage joint, and the leakage channel communicates with both the inside and outside of the oil pipe. The schlieren assembly includes a point light source assembly, a first mirror assembly, a second mirror assembly, a light chopping assembly, and a high-speed camera assembly arranged in sequence along a Z-shaped optical path. During installation, the point light source assembly, the first mirror assembly, the second mirror assembly, the light chopping assembly, and the high-speed camera assembly are arranged along the Z-shaped optical path so that a parallel optical path can be formed between the first mirror assembly and the second mirror assembly. The jacket structure assembly is arranged between the first mirror assembly and the second mirror assembly, and the light can pass through the oil pipe, and the axis of the oil pipe is parallel to the optical path. Then, a leakage joint with the aperture of the leakage channel being the experimental aperture is selected and connected to the oil pipe. Finally, the fluid supply assembly is connected to one end of the leakage joint located inside the oil pipe. During the experiment, the first mirror assembly shoots the light emitted by the point light source assembly in a direction parallel to the axis of the oil pipe towards the oil pipe. The second mirror assembly receives the light passing through the oil pipe and focuses and reflects the light to the light chopping assembly. The high-speed camera receives the light passing through the light chopping assembly. The oil pipe leakage flow field observation experimental system provided by the present invention forms a Z-shaped parallel optical path through double mirrors, making the oil pipe in the test area in parallel light, and the axis of the oil pipe is parallel to the light, avoiding the error caused by light refraction, thereby generating a clear and ghost-free schlieren image. The system simulates the change of the oil pipe leakage flow field and truly restores the physical field structure of the downhole oil pipe leakage. Through the observation in the axial direction, the deflection of the parallel light by the circular casing wall during side observation or radial observation is avoided, effectively avoiding the distortion of the schlieren image. The system can accurately determine the shape and flow field characteristics of the leaked fluid, provide scientific and effective data support for oil pipe leakage detection and treatment, improve the detection accuracy, and guide engineering practice.

[0028] The following combines Figures 1 to 14 to describe the oil pipe leakage flow field observation experimental system of the present invention.

[0029] An embodiment of the present invention provides an oil pipe leakage flow field observation experimental system, including a jacket structure assembly, a schlieren assembly, and a fluid supply assembly.

[0030] The jacket structure assembly includes a bracket, a casing 110, and an oil pipe 120. The casing 110 and the oil pipe 120 are both connected to the bracket. After connection, the casing 110 is arranged inside the oil pipe 120, and the oil pipe 120 is coaxially arranged with the casing 110. A leakage joint 300 is provided on the side wall of the oil pipe 120. The leakage joint 300 is detachably connected to the oil pipe 120. A leakage channel is provided inside the leakage joint 300, and the leakage channel communicates with both the inside and outside of the oil pipe 120.

[0031] Specifically, the length of the tubing 120 should be greater than that of the casing 110, and both ends of the tubing 120 extend outward to the outside of the casing 110. The bracket includes a first support frame and a second support frame. The first support frame is used to support at the bottom of the casing 110, and the second support frame is used to support at the bottom of the part of the tubing 120 that extends beyond the casing 110.

[0032] The second support frame may include a bottom plate 210, an L-shaped right-angle plate 220, and an arc-shaped bracket 230. Among them, at least two L-shaped right-angle plates 220 and arc-shaped brackets 230 are provided. In this embodiment, two L-shaped right-angle plates 220 and arc-shaped brackets 230 are provided. One L-shaped right-angle plate 220 is respectively provided at the positions near the left and right ends on the front side of the top of the bottom plate 210. The bottom end of the vertical part of the L-shaped right-angle plate 220 is connected to the bottom plate 210, the front end of the horizontal part of the L-shaped right-angle plate 220 is connected to the top end of the vertical part, and the rear end extends horizontally backward. An arc-shaped bracket 230 is respectively connected to each L-shaped right-angle plate 220, and the front end of the arc-shaped bracket 230 is connected to the rear end of the horizontal part of the L-shaped right-angle plate 220. Among them, the bottom plate 210, the L-shaped right-angle plate 220, and the arc-shaped bracket 230 can be welded or integrally formed. When in use, the tubing 120 can be Figure 6 placed directly on the two arc-shaped brackets 230 as shown. At this time, the axis of the tubing 120 extends horizontally in the left-right direction.

[0033] The first support frame may include at least two, and multiple first support frames are distributed along a certain straight line. In this embodiment, two first support frames are provided and distributed in the left-right direction. Each first support frame includes a first height adjustment mechanism, an upper arc-shaped clamp 240, and a lower arc-shaped clamp 250.

[0034] Horizontal extension plates are provided at both ends of the upper arc-shaped clamp 240 and the lower arc-shaped clamp 250, and bolt holes are provided on the horizontal extension plates. The top of the first height adjustment mechanism is connected to the bottom of the lower arc-shaped clamp 250, and the bottom of the first height adjustment mechanism can be connected to the bottom plate 210 of the second support frame by screws. The upper arc-shaped clamp 240 is provided on the top of the lower arc-shaped clamp 250, and their bolt holes are aligned. After placement, they can be connected by bolts. When in use, the upper arc-shaped clamp 240 and the lower arc-shaped clamp 250 respectively wrap around the top and bottom of the sleeve and are fastened by bolts, so that the upper arc-shaped clamp 240 and the lower arc-shaped clamp 250 are tightly held on the outside of the sleeve.

[0035] Among them, the inner diameter of the upper arc-shaped clamp 240 and the lower arc-shaped clamp 250 can be 170 mm, and the thickness is 3 mm.

[0036] The first height adjustment mechanism may include a fixed cylinder 260, an adjustment rod 270, and a fastening bolt. An installation plate is provided at the bottom of the fixed cylinder 260, and screw holes are provided on the installation plate. Screw holes are also provided on the bottom plate 210 of the corresponding second support frame. When connecting, after aligning the screw holes on the installation plate with the screw holes on the bottom plate 210, screws are used for fastening. In this way, the fixed cylinder 260 is fixed to the bottom plate 210. The bottom end of the adjustment rod 270 is inserted into the fixed cylinder 260 and is slidably connected to the fixed cylinder 260. The top of the adjustment rod 270 is connected to the bottom of the lower arc-shaped clamp 250. Bolt holes are provided at a position near the top on the outer side of the fixed cylinder 260, and the fastening bolt is screwed into the bolt hole.

[0037] When it is necessary to adjust the extended length of the adjustment rod 270, loosen the fastening bolt to disconnect the fastening bolt from the adjustment rod 270. At this time, the adjustment rod 270 can freely expand and contract. When it is necessary to fix the height of the first height adjustment mechanism, tighten the fastening bolt to restrict the telescopic movement of the adjustment rod 270.

[0038] During installation, support the sleeve 110 on the two lower arc-shaped clamps 250, and then connect the corresponding upper arc-shaped clamps 240 to the two lower arc-shaped clamps 250 respectively to hold the sleeve 110 tightly between the upper arc-shaped clamp 240 and the lower arc-shaped clamp 250. Then pass the oil pipe 120 through the sleeve 110 and support the oil pipe 120 on the two arc-shaped brackets 230. After installation, the axes of the sleeve 110 and the oil pipe 120 are located in the same vertical plane. If the oil pipe 120 and the sleeve 110 are not coaxial at this time, the height of the first height adjustment mechanism can be adjusted to make the sleeve 110 and the oil pipe 120 coaxial.

[0039] The leakage joint 300 includes a first joint 310 and a second joint 320. One end of the first joint 310 is located inside the oil pipe 120 and is used for detachably connecting to the fluid supply assembly. The other end of the first joint 310 passes through the oil pipe 120. The second joint 320 is detachably connected to one end of the first joint 310 located outside the oil pipe 120. The leakage channel includes a through hole 314 provided on the first joint 310 and a leakage hole 323 provided on the second joint 320, and the through hole 314 is communicated with the leakage hole 323.

[0040] Specifically, a threaded hole for installing the leakage joint 300 is provided on the side wall of the oil pipe 120, and the threaded hole can penetrate the oil pipe 120 along the radial direction of the oil pipe 120.

[0041] The first joint 310 may include a first hexagonal joint portion 311, an extension cylinder portion 312, and a first threaded connection portion 313. A threaded hole is provided inside the first hexagonal joint portion 311 for threaded connection with the fluid outlet end of the fluid supply assembly. The extension cylinder portion 312 is connected between the first hexagonal joint portion 311 and the first threaded connection portion 313. The first threaded connection portion 313 is provided with external threads. A through hole 314 penetrates through the first hexagonal joint portion 311, the extension cylinder portion 312, and the first threaded connection portion 313.

[0042] The second joint 320 may include a second hexagonal joint portion 321 and a second threaded connection portion 322. A leakage hole 323 axially penetrates through the second hexagonal joint portion 321 and the second threaded connection portion 322 along the second joint 320. Internal threads are provided inside the second threaded connection portion 322, and external threads are provided outside.

[0043] During connection, the second joint 320 is screwed into the threaded hole of the oil pipe 120 from the outside of the oil pipe 120 through the external threads of the second threaded connection portion 322, and the first joint 310 is connected to the second joint 320 inside the oil pipe 120 through the external threads of the first threaded connection portion 313 and the internal threads of the second threaded connection portion 322 of the second joint 320.

[0044] The advantage of the detachable connection between the first joint 310 and the second joint 320 is that different second joints 320 may be provided with leakage holes 323 having different hole diameters or different cross-sectional shapes. In this way, by replacing the second joint 320, the effect of adjusting the hole diameter or cross-sectional shape of the leakage hole 323 can be achieved.

[0045] The oil pipe 120 includes a pipe body 121 and a window cover 122. An operation window is provided on the pipe body 121 at least at a position opposite to the leakage joint 300, so as to facilitate operation when the leakage joint 300 is connected to the fluid supply assembly. The window cover 122 is detachably connected to the pipe body 121 for closing or opening the operation window. After the window cover 122 is connected to the pipe body 121, the combination of the two forms a cylindrical structure.

[0046] In a specific embodiment, the oil pipe 120 is a cylindrical structure. When the oil pipe 120 is placed horizontally, a horizontal cutting plane passing through the axis of the oil pipe 120 divides the oil pipe 120 from the left end of the oil pipe 120 to the right. When approaching the right end of the oil pipe 120, or it may be when cutting to the position of four-fifths of the total length of the oil pipe 120, stop cutting. Then a vertical cutting plane cuts downward from the position reached by the horizontal cutting plane until it intersects with the horizontal cutting plane.

[0047] At this time, the part above the horizontal cutting plane is called the window cover 122, and the remaining part is called the pipe body 121. After the pipe body 121 loses the window cover 122, the open part at the top is called the operation window.

[0048] A first pin body 124 extending to the right can be provided at the right end face of the window cover 122, and a first pin hole 126 is provided on the end face where the pipe body 121 contacts the right end face of the window cover 122. The position of the first pin hole 126 corresponds to that of the first pin body 124.

[0049] Two second pin holes 127 are respectively provided on the left end face of the window cover 122 and the left end face of the pipe body 121. A cover body 123 is further provided on the left end face of the oil pipe 120. Four second pin bodies 125 corresponding to the second pin holes 127 are provided on the right end face of the cover body 123.

[0050] When the window cover 122 is connected to the pipe body 121, a first pin body 124 on the right side of the window cover 122 is inserted into a first pin hole 126 of the pipe body 121, and then the four second pin bodies 125 of the cover body 123 are inserted into the four second pin holes 127 of the window cover 122 and the pipe body 121.

[0051] Among them, the first pin body 124 and the first pin hole 126, and the second pin body 125 and the second pin hole 127 are all interference fits. The above-mentioned first pin body 124, second pin body 125, first pin hole 126 and second pin hole 127 form an axial limiting structure and a radial limiting structure between the window cover 122 and the pipe body 121.

[0052] It should be noted that the threaded hole for installing the leakage joint 300 on the oil pipe 120 is provided on the pipe body 121 and is within the coverage of the operation window.

[0053] When the oil pipe 120 installed with the leakage joint 300 is connected to the fluid supply assembly, the fluid supply pipeline of the fluid supply assembly is extended into the oil pipe 120 through the right end of the oil pipe 120. The window cover 122 is opened, and the fluid outlet end of the fluid supply pipeline is connected to the first hexagonal joint part 311 of the leakage joint 300 through the operation window. This test bench can simulate the restricted jet flow formed after the leakage of high-pressure gas or high-pressure liquid passes through the small hole throttling of the leakage hole 323.

[0054] In some embodiments, both the first mirror assembly 420 and the second mirror assembly 430 include a lens 421 and a form adjustment mechanism. The form adjustment mechanism at least includes a second height adjustment mechanism, a horizontal movement mechanism 423, a deflection adjustment mechanism 424 and a pitch adjustment mechanism 425.

[0055] Specifically, the lens 421 can be a concave mirror.

[0056] The form adjustment mechanism includes a second height adjustment mechanism, a horizontal movement mechanism 423, a deflection adjustment mechanism 424, and a pitch adjustment mechanism 425.

[0057] For the specific structure of the second height adjustment mechanism, reference can be made to the first height adjustment mechanism, or the second height adjustment mechanism can be a scissor arm lifting mechanism 422. A base is provided at the bottom of the scissor arm lifting mechanism 422, and a top plate is provided at the top.

[0058] The horizontal movement mechanism 423 can be a lead screw nut mechanism. The lead screw nut mechanism is arranged on the top surface of the top plate of the scissor arm lifting mechanism 422 and includes a lead screw and a slider. The slider is slidably connected to the top plate, the lead screw is rotatably connected to the top plate, a threaded hole is provided on the slider, and the threaded hole is threadedly connected to the lead screw. When the lead screw rotates, the slider can be driven to move linearly.

[0059] The deflection adjustment mechanism 424 includes a first shaft hole and a first rotating shaft. The first shaft hole is provided at the top of the slider and extends in the vertical direction. The first rotating shaft is rotatably inserted into the first shaft hole.

[0060] The pitch adjustment mechanism 425 can include a semi-circular support frame. The arc top of the semi-circular support frame is fixedly connected to the top end of the first rotating shaft. Second shaft holes are provided at both ends of the semi-circular support frame. The axes of the second shaft holes are collinear and extend in the horizontal direction. The extending direction of the second shaft hole is perpendicular to the axis of the semi-circular support frame.

[0061] Two second rotating shafts extending radially outward are provided at the outer edge of the lens 421. The second rotating shafts are rotatably connected to the second shaft holes, thereby realizing the pitch adjustment of the lens 421.

[0062] It should be noted that in order to fix the lens 421 at the angle reached after deflection or pitch adjustment, damping members are provided between the first rotating shaft and the first shaft hole, and between the second rotating shaft and the second shaft hole.

[0063] In a specific embodiment, the diameter of the lens 421 of the first mirror assembly 420 and the second mirror assembly 430 is 203 mm, and the observable flow field range is a circular area with a diameter of 203 mm. The center height of the lens 421 of the first mirror assembly 420 and the second mirror assembly 430 can be adjusted by the second height adjustment mechanism. The pitch fine adjustment range of the lens 421 is within ±5°, the deflection angle fine adjustment range is within ±20°, and the horizontal fine adjustment length is within ±100 mm.

[0064] In some embodiments, the point light source assembly 410 includes an LED point light source 411, a cooling fan 412, a third height adjustment mechanism 413, and a first guide rail 414.

[0065] Among them, the specific structure of the third height adjustment mechanism 413 can refer to the first height adjustment mechanism. The LED point light source 411 is arranged on the top of the third height adjustment mechanism 413, and the heat dissipation fan 412 is arranged on the LED point light source 411 to dissipate heat for it.

[0066] The bottom of the third height adjustment mechanism 413 is slidably connected to the first guide rail 414, and a locking bolt is arranged between the two. By tightening or loosening the locking bolt, the position of the third height adjustment mechanism 413 on the first guide rail 414 can be fixed and released.

[0067] In a specific embodiment, the included angle between the extending direction of the first guide rail 414 and the straight line where the axis of the oil pipe 120 is located can be 8 degrees, the length of the first guide rail 414 can be 500 mm, the power of the LED point light source 411 is adjustable from 5 to 15 w, and the height of the LED point light source 411 is adjustable from 10 to 30 cm.

[0068] In some embodiments, the high-speed camera assembly 450 and the light cutting assembly 440 are jointly arranged on a second guide rail 453. The included angle between the extending direction of the second guide rail 453 and the straight line where the axis of the oil pipe 120 is located can be 8 degrees, and the light cutting assembly 440 is arranged on one side close to the second mirror assembly 430.

[0069] The light cutting assembly 440 includes a light cutting device 441 and a fourth height adjustment mechanism 442. The specific structure of the fourth height adjustment mechanism 442 can refer to the first height adjustment mechanism. The light cutting device 441 is arranged on the top of the fourth height adjustment mechanism 442, and the bottom of the fourth height adjustment mechanism 442 is slidably connected to the second guide rail 453. The specific connection structure can refer to the connection structure between the third height adjustment mechanism 413 and the first guide rail 414.

[0070] The high-speed camera assembly 450 includes a high-speed camera 451 and a fifth height adjustment mechanism 452. The specific structure of the fifth height adjustment mechanism 452 can refer to the first height adjustment mechanism. The high-speed camera assembly 450 is arranged on the top of the fifth height adjustment mechanism 452, and the bottom of the fifth height adjustment mechanism 452 is slidably connected to the second guide rail 453. The specific connection structure can refer to the connection structure between the third height adjustment mechanism 413 and the first guide rail 414.

[0071] In a specific embodiment, the high-speed camera 451 can be a black-and-white or color camera with a resolution within 1080, adjustable exposure time and sampling frame rate. The adjustable range of the light cutting assembly 440 is within 10 mm, and the overall height is adjustable from 10 to 30 cm.

[0072] The experimental method of the oil pipe leakage flow field observation experimental system provided by the present invention is as follows: According to Figure 2The schlieren component and the jacket structure component shown in the figure are arranged such that the central positions of the LED point light source 411, the lens 421, the light cutting component 440, and the high-speed camera 451 are at the same height, which is the height where the axis of the oil pipe 120 is located. The axis of the oil pipe 120 is parallel to the reflected light of the first mirror component 420. The LED point light source 411 is located at the focal length of the lens 421 of the first mirror, and the light cutting component 440 is located at the focal length of the lens 421 of the second mirror.

[0073] Separate the window cover 122 from the pipe body 121, then connect the fluid outlet end of the fluid supply component to the second threaded hole of the first hexagonal joint 311, and finally connect the window cover 122 to the pipe body 121. The fluid outlet end of the fluid supply component is a high-pressure fluid joint with a constant back pressure, which can provide high-pressure fluid of any gas or liquid with a constant back pressure.

[0074] Fine-tune the focal length of the high-speed camera 451 for focusing, and fine-tune the light cutting size of the light cutting device 441 to make the image of the high-speed camera 451 clearly visible.

[0075] Turn on the fluid supply component with a constant back pressure to supply gas or liquid. After the high-pressure fluid is throttled by the leakage hole 323 on the second joint 320, it impacts the inner wall of the sleeve 110. Turn on the high-speed acquisition mode of the high-speed camera 451 to record the flow field pattern and characteristics of the leakage-limited jet flow field of the oil pipe 120.

[0076] By controlling the start time of supplying gas or liquid by the fluid supply component to be the same as the start time of turning on the high-speed acquisition mode of the high-speed camera 451, the transient flow field of the oil pipe 120 leakage is observed. The development process of the transient flow field pattern and characteristics of the leakage-limited jet flow field of the oil pipe 120 after the high-pressure fluid is throttled by the leakage hole 323 can be recorded.

[0077] Using the above experimental system and experimental method, the transient leakage flow field pattern and flow field characteristic results under the experimental conditions of CO2 fluid with a pressure of 2 MPa and a leakage hole diameter of 1 mm are as Figure 14 shown. The transient leakage flow front and the jet shock structure characteristics of the limited jet flow field can be observed without image processing.

[0078] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be covered by the scope of the claims and the specification of the present application. In particular, as long as there is no structural conflict, the technical features mentioned in each embodiment can be combined in any way. The present application is not limited to the specific embodiments disclosed in the text, but includes all technical solutions that fall within the scope of the claims.

Claims

1. An observation experiment system for the flow field of oil pipe leakage, characterized in that Comprising: A jacket structure assembly, including a bracket, a sleeve (110) and an oil pipe (120), wherein the sleeve (110) and the oil pipe (120) are both connected to the bracket, the oil pipe (120) is coaxially arranged with the sleeve (110), and the oil pipe (120) is arranged inside the sleeve (110). A leakage joint (300) is arranged on the side wall of the oil pipe (120), and the leakage joint (300) is detachably connected to the oil pipe (120). A leakage channel is arranged inside the leakage joint (300), and the leakage channel communicates the inner and outer sides of the oil pipe (120); A schlieren assembly, including a point light source assembly (410), a first mirror assembly (420), a second mirror assembly (430), a light chopping assembly (440) and a high-speed camera assembly (450) arranged in sequence along a Z-shaped optical path. The first mirror assembly (420) is used to direct the light emitted by the point light source assembly (410) towards the oil pipe (120) along a direction parallel to the axis of the oil pipe (120). The second mirror assembly (430) is used to receive and focus the reflected light passing through the oil pipe (120) to the light chopping assembly (440). The high-speed camera (451) is used to receive the light passing through the light chopping assembly (440); A fluid supply assembly, the fluid outlet end of the fluid supply assembly is detachably connected to one end of the leakage joint (300) located inside the oil pipe (120), and the fluid supply assembly communicates with the leakage channel.

2. The oil pipe leakage flow field observation experimental system according to claim 1, characterized in that The length of the oil pipe (120) is greater than the length of the sleeve (110). Both ends of the oil pipe (120) extend outside the sleeve (110). The bracket includes a first support frame and a second support frame. The first support frame supports the bottom of the sleeve (110), and the second support frame supports the bottom of the part of the oil pipe (120) extending outside the sleeve (110).

3. The tubing leakage flow field observation experimental system according to claim 2, characterized in that When the sleeve (110) is connected to the first support frame and the oil pipe (120) is connected to the second support frame, the axes of the sleeve (110) and the oil pipe (120) are located in the same vertical plane, and at least one of the first support frame and the second support frame is provided with a first height adjustment mechanism.

4. The oil pipe leakage flow field observation experimental system according to claim 1, characterized in that, The leakage joint (300) includes: A first joint (310), one end of the first joint (310) is located inside the oil pipe (120) and is used for detachably connecting to the fluid supply assembly, and the other end of the first joint (310) passes through the oil pipe (120); A second joint (320), the second joint (320) is detachably connected to one end of the first joint (310) located outside the oil pipe (120); The leakage channel includes a through hole arranged on the first joint (310) and a leakage hole (323) arranged on the second joint (320), and the through hole communicates with the leakage hole (323).

5. The oil pipe leakage flow field observation experimental system according to claim 1, characterized in that The oil pipe (120) includes: A tube body (121) is provided with an operation window at least at a position opposite to the leakage joint (300). A window cover (122) is detachably connected to the tube body (121) and is used to close or open the operation window. After the window cover (122) is connected to the tube body (121), the combination forms a cylindrical structure.

6. The oil pipe leakage flow field observation experimental system according to claim 5, characterized in that The operation window extends from one end of the tube body (121) to a position near the other end along the axial direction of the tube body (121), and the area where the operation window is located covers the leakage joint (300). The window cover (122) is an arc-shaped cover plate, and an axial limiting structure and a radial limiting structure are provided between the window cover (122) and the tube body (121).

7. The oil pipe leakage flow field observation experimental system according to claim 1, characterized in that Both the first mirror assembly (420) and the second mirror assembly (430) include a lens (421) and a shape adjustment mechanism. The shape adjustment mechanism at least includes a second height adjustment mechanism, a horizontal movement mechanism (423), a deflection adjustment mechanism (424), and a pitch adjustment mechanism (425).

8. The oil pipe leakage flow field observation experimental system according to claim 1, characterized in that The point light source assembly (410) includes an LED point light source (411), a third height adjustment mechanism (413), and a first guide rail (414). The third height adjustment mechanism (413) is provided at the bottom of the LED point light source (411), and the bottom of the third height adjustment mechanism (413) is slidably connected to the first guide rail (414).

9. The oil pipe leakage flow field observation experimental system according to claim 1, characterized in that The light cutting assembly (440) includes a light cutting device (441), a fourth height adjustment mechanism (442), and a second guide rail (453). The fourth height adjustment mechanism (442) is provided at the bottom of the light cutting device (441), and the bottom of the fourth height adjustment mechanism (442) is slidably connected to the second guide rail (453).

10. The oil pipe leakage flow field observation experimental system according to claim 9, wherein, The high-speed camera assembly (450) includes a high-speed camera (451) and a fifth height adjustment mechanism (452). The fifth height adjustment mechanism (452) is provided at the bottom of the high-speed camera (451).

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