阅读说明：本技术 天然气水合物固态流化采掘腔流场模拟装置及实验方法 (Natural gas hydrate solid fluidization excavation cavity flow field simulation device and experimental method ) 是由 杨浦 方小宇 陆江 马晓龙 夏冬青 刘洪刚 于 2021-08-16 设计创作，主要内容包括：本发明公开了天然气水合物固态流化采掘腔流场模拟装置及实验方法,天然气水合物固态流化采掘腔流场模拟装置包括流场模拟装置,流场模拟装置包括密封箱体、模拟管、射流管和回收管,射流管的第一端与回收管的第一端分别插入至密封箱体的内部,射流管的第一端设有射流孔,回收管的第一端设有回收孔,射流管用于引导射流流体进入密封箱体,回收管用于引导混合流体离开密封箱体,模拟管安装于密封箱体内,射流孔和回收孔均位于模拟管内。本发明通过密封箱体模拟采掘腔内射流破碎时的场景,并采用模拟管模拟采掘腔内壁,从而模拟射流破碎时流场对采掘腔内壁的影响。本发明涉及天然气水合物固态流化模拟装置技术领域。(The invention discloses a natural gas hydrate solid fluidization excavation cavity flow field simulation device and an experimental method, wherein the natural gas hydrate solid fluidization excavation cavity flow field simulation device comprises a flow field simulation device, the flow field simulation device comprises a sealed box body, a simulation pipe, a jet pipe and a recovery pipe, the first end of the jet pipe and the first end of the recovery pipe are respectively inserted into the sealed box body, the first end of the jet pipe is provided with a jet hole, the first end of the recovery pipe is provided with a recovery hole, the jet pipe is used for guiding jet fluid to enter the sealed box body, the recovery pipe is used for guiding mixed fluid to leave the sealed box body, the simulation pipe is arranged in the sealed box body, and the jet hole and the recovery hole are both positioned in the simulation pipe. The invention simulates the scene of jet flow crushing in the excavation cavity through the sealing box body and simulates the inner wall of the excavation cavity by adopting the simulation pipe, thereby simulating the influence of a flow field on the inner wall of the excavation cavity when the jet flow is crushed. The invention relates to the technical field of natural gas hydrate solid fluidization simulation devices.)

1. The gas hydrate solid-state fluidization excavation cavity flow field simulation device is characterized by comprising: flow field analogue means (1), flow field analogue means (1) is including sealed box (11), simulation pipe (12), efflux pipe (13) and recovery tube (14), the first end of efflux pipe (13) with the first end of recovery tube (14) inserts respectively to the inside of sealed box (11), the first end of efflux pipe (13) is equipped with efflux hole (131), the first end of recovery pipe (14) is equipped with recovery hole (141), efflux pipe (13) are used for guiding efflux fluid to get into sealed box (11), recovery pipe (14) are used for guiding the mixed fluid to leave sealed box (11), simulation pipe (12) install in sealed box (11), efflux hole (131) with recovery hole (141) all are located in simulation pipe (12).

2. The natural gas hydrate solid-state fluidization excavation cavity flow field simulation device according to claim 1, wherein: the natural gas hydrate solid-state fluidization excavation cavity flow field simulation device further comprises a mixing device, a booster pump and a self-sucking pump, wherein the mixing device is used for mixing solid-phase particles with a liquid phase, two ends of the booster pump are respectively connected to the mixing device and a second end of the jet pipe (13), and two ends of the self-sucking pump are respectively connected to a second end of the recovery pipe (14) and the mixing device.

3. The natural gas hydrate solid-state fluidization excavation cavity flow field simulation device according to claim 1, wherein: the sealed box body (11) comprises a sealed box body (111) and an end cover (112), the end cover (112) is detachably connected with one end of the sealed box body (111), and the simulation tube (12) can be taken out of the sealed box body (11).

4. The natural gas hydrate solid-state fluidization excavation cavity flow field simulation device according to claim 1, wherein: the number of the jet holes (131) and the number of the recovery holes (141) are more than two.

5. The natural gas hydrate solid-state fluidization excavation cavity flow field simulation device according to claim 1, wherein: the simulation tube (12) is provided with a first pressure detection device.

6. The natural gas hydrate solid-state fluidization excavation cavity flow field simulation device according to claim 1, wherein: and a weight sensor is arranged at the bottom of the sealed box body (11).

7. The natural gas hydrate solid-state fluidization excavation cavity flow field simulation device according to claim 1, wherein: the inner space of the simulation pipe (12) is communicated with the inner space of the sealed box body (11), and the sealed box body (11) is provided with an overflow valve.

8. The natural gas hydrate solid-state fluidization excavation chamber flow field simulation device according to claim 7, wherein: and the sealed box body (11) is provided with a second pressure detection device.

9. The natural gas hydrate solid-state fluidization excavation cavity flow field simulation device according to claim 1, wherein: the sealed box body (11) and the simulation tube (12) are made of transparent materials.

10. An experimental method based on a natural gas hydrate solid-state fluidization excavation cavity flow field simulation device according to any one of claims 1 to 9, characterized by comprising:

s1, manufacturing the simulation pipe (12), and determining the positions of the jet hole (131) and the recovery hole (141) in the sealed box body (11), and the arrangement mode, the geometric shape and the number of the jet hole (131) and the recovery hole (141);

s2, arranging a first pressure detection device on the inner wall of the simulation pipe (12);

s3, mounting the simulation pipe (12), the jet pipe (13) and the recovery pipe (14) to the sealed box body (11), sealing the end face of the sealed box body (11), injecting water into the sealed box body (11) to fill the inner space of the sealed box body, and checking the sealing performance of the sealed box body (11);

s4, starting the mixing device to obtain a solid-liquid phase mixture;

s5, starting the booster pump and the self-priming pump, forming a flow field in the sealed box body (11), and recording experimental data;

s6, obtaining the change rate of the weight of the sealed box body (11) along with time according to the real-time weight value of the weight sensor, so as to calculate the deposition rate of solid-phase particles in the sealed box body (11), and further adjust the mixing proportion of the mixing device and the output power of the booster pump;

s7, changing at least one of the roughness, the geometric shape and the geometric dimension of the inner surface of the simulation pipe (12), the mixing proportion of the mixing device, the output power of the booster pump, the positions, the number and the sizes of the jet hole (131) and the recovery hole (141) and the overflow critical value of the overflow valve, and repeating the steps from S1 to S6.

Technical Field

The invention relates to a flow field simulation device of a gas hydrate solid fluidization excavation cavity and an experimental method, belonging to the technical field of gas hydrate solid fluidization simulation devices.

Background

The natural gas hydrate is also called combustible ice, is an ice-like crystalline substance formed by natural gas and water under high pressure and low temperature conditions, and is distributed in deep sea or land permafrost. Because only a small amount of carbon dioxide and water are generated after the combustion, the pollution is far less than that of coal, petroleum and the like, and the reserves are huge, the energy is a clean energy with great development prospect. Among natural gas hydrate mining methods, the solid-state fluidized mining method is one of the methods most likely to realize commercial mining of hydrates, and performs an in-situ jet breaking operation on a hydrate-containing sediment layer by using a high-pressure submerged water jet technology, so that the hydrate-containing sediment layer is locally fluidized and then collected by using a suction device to realize a natural gas hydrate mining process.

Before mining, a mining drill bit firstly drills into a sediment layer containing hydrate to form a borehole, a jet device is started in the borehole to jet and break the hydrate layer and form a mining cavity, and the hydrate is absorbed by a recovery device and conveyed to a mining ship after being broken by high-pressure jet, so that the mining work is completed. However, the structure of the excavation cavity also changes with the progress of excavation work, and according to the existing research, the flow field distribution in the excavation cavity has important influence on the recovery rate of hydrate-containing sediments and the stability of the well wall, and particularly the influence of the multi-nozzle combined jet flow field on the internal environment of the excavation cavity needs to be further researched. At present, most of the existing solid fluidization simulation devices only simulate jet flow crushing and hydrate collection, and the simulation analysis is carried out on the flow field in the excavation cavity, so that the reduction degree of the underground multi-nozzle combined jet flow crushing excavation environment is insufficient, and the requirement of further research cannot be met.

Disclosure of Invention

The invention aims to solve at least one technical problem in the prior art, and provides a natural gas hydrate solid fluidization excavation cavity flow field simulation device and an experimental method, which can simulate the flow field distribution under the actual jet flow excavation working condition.

According to an embodiment of the first aspect of the present invention, a natural gas hydrate solid fluidization excavation cavity flow field simulation device is provided, which includes a flow field simulation device, where the flow field simulation device includes a sealed box, a simulation pipe, a jet pipe and a recovery pipe, a first end of the jet pipe and a first end of the recovery pipe are respectively inserted into the sealed box, the first end of the jet pipe is provided with a jet hole, the first end of the recovery pipe is provided with a recovery hole, the jet pipe is used for guiding jet fluid to enter the sealed box, the recovery pipe is used for guiding mixed fluid to leave the sealed box, the simulation pipe is installed in the sealed box, and the jet hole and the recovery hole are both located in the simulation pipe.

According to an embodiment of the first aspect of the present invention, the natural gas hydrate solid-state fluidization excavation cavity flow field simulation apparatus further includes a mixing device, a booster pump, and a self-priming pump, the mixing device is configured to mix solid-phase particles with a liquid phase, two ends of the booster pump are respectively connected to the mixing device and the second end of the jet pipe, and two ends of the self-priming pump are respectively connected to the second end of the recovery pipe and the mixing device.

According to an embodiment of the first aspect of the present invention, further, the sealed box body includes a sealed box body and an end cover, the end cover is detachably connected to one end of the sealed box body, and the dummy tube can be taken out of the sealed box body.

According to an embodiment of the first aspect of the present invention, further, the number of the jet holes and the number of the recovery holes are both two or more.

According to an embodiment of the first aspect of the present invention, further, the simulation tube is provided with a first pressure detection device.

According to an embodiment of the first aspect of the present invention, further, a weight sensor is disposed at the bottom of the sealed box body.

According to an embodiment of the first aspect of the present invention, further, the inner space of the dummy pipe is communicated with the inner space of the sealed box provided with an overflow valve.

According to an embodiment of the first aspect of the present invention, further, the sealed box body is provided with a second pressure detection device.

According to an embodiment of the first aspect of the present invention, the sealed box and the dummy tube are made of transparent materials.

According to an embodiment of the second aspect of the invention, an experimental method based on any one of the above natural gas hydrate solid-state fluidization excavation cavity flow field simulation devices is provided, and the experimental method comprises the following steps:

s1, manufacturing the simulation tubes, and determining the positions of the jet holes and the recovery holes in the sealed box body, and the arrangement mode, the geometric shape and the number of the jet holes and the recovery holes;

s2, arranging a first pressure detection device on the inner wall of the simulation pipe;

s3, mounting the simulation pipe, the jet pipe and the recovery pipe to the sealed box body, sealing the end face of the sealed box body, injecting water into the sealed box body to fill the inner space of the sealed box body, and checking the sealing performance of the sealed box body;

s4, starting the mixing device to obtain a solid-liquid phase mixture;

s5, starting the booster pump and the self-priming pump, forming a flow field in the sealed box body, and recording experimental data;

s6, obtaining the change rate of the weight of the sealed box body along with time according to the real-time weight value of the weight sensor, so as to calculate the deposition rate of solid-phase particles in the sealed box body, and further adjust the mixing proportion of the mixing device and the output power of the booster pump;

s7, changing at least one of the roughness, the geometric shape and the geometric dimension of the inner surface of the simulation pipe, the mixing proportion of the mixing device, the output power of the booster pump, the positions, the number and the sizes of the jet hole and the recovery hole and the overflow critical value of the overflow valve, and repeating the steps from S1 to S6.

The invention has the beneficial effects that: the invention simulates the scene of jet flow crushing in the excavation cavity through the sealing box body and simulates the inner wall of the excavation cavity by adopting the simulation pipe, thereby simulating the influence of a flow field on the inner wall of the excavation cavity when the jet flow is crushed.

Drawings

In order to more clearly illustrate the technical solution in the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly described below. It is clear that the described figures are only some embodiments of the invention, not all embodiments, and that a person skilled in the art can also derive other designs and figures from them without inventive effort.

FIG. 1 is a front view of an embodiment of a first aspect of the present invention;

fig. 2 is a cross-sectional view of an embodiment of the first aspect of the present invention.

Detailed Description

Reference will now be made in detail to the present preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout.

In the description of the present invention, it should be understood that the orientation or positional relationship referred to in the description of the orientation, such as the upper, lower, front, rear, left, right, etc., is based on the orientation or positional relationship shown in the drawings, and is only for convenience of description and simplification of description, and does not indicate or imply 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 limiting the present invention.

In the description of the present invention, the meaning of a plurality of means is one or more, the meaning of a plurality of means is two or more, and larger, smaller, larger, etc. are understood as excluding the number, and larger, smaller, inner, etc. are understood as including the number. If the first and second are described for the purpose of distinguishing technical features, they are not to be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated or implicitly indicating the precedence of the technical features indicated.

In the description of the present invention, unless otherwise explicitly limited, terms such as arrangement, installation, connection and the like should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meanings of the above terms in the present invention in combination with the specific contents of the technical solutions.

Referring to fig. 1 to 2, the natural gas hydrate solid-state fluidization excavation cavity flow field simulation device in the first aspect embodiment of the present invention includes a flow field simulation device 1, where the flow field simulation device 1 includes a sealed box 11, a simulation pipe 12, a jet pipe 13, and a recovery pipe 14, and a first end of the jet pipe 13 and a first end of the recovery pipe 14 are respectively inserted into the sealed box 11, so as to achieve communication between the jet pipe 13, the sealed box 11, and the recovery pipe 14. The first end of the jet pipe 13 is provided with a jet hole 131 for simulating jet flow crushing of the natural gas hydrate; the first end of the recovery pipe 14 is provided with a recovery hole 141 for simulating recovery of natural gas hydrate. The jet pipe 13 is used to guide the jet fluid into the sealed tank 11, and the recovery pipe 14 is used to guide the mixed fluid out of the sealed tank 11. The inner wall of the simulation pipe 12 is used for simulating the inner wall of a mining cavity, the simulation pipe 12 is installed in the sealed box body 11, the jet hole 131 and the recovery hole 141 are both located in the simulation pipe 12, and particularly, the simulation pipe 12 can be designed into various geometric shapes, so that mining cavities with different structures can be simulated, and the universality of the simulation device is improved.

In some embodiments, an experimenter may fix the solid phase sample on the inner wall of the simulation tube 12, and input high-pressure jet flow into the jet pipe 13, and the high-pressure jet flow is ejected from the jet hole 131, so that the solid phase sample can be crushed, and the actual jet flow crushing condition is simulated; the influence of the flow field on the inner wall of the simulation tube 12 is recorded, and then the influence of the flow field on the inner wall of the excavation cavity is simulated.

In this embodiment, natural gas hydrate solid-state fluidization excavation cavity flow field analogue means still includes compounding device, booster pump and self priming pump, and the compounding device is used for mixing solid-phase particle and liquid phase, the produced solid-liquid mixture when the simulation efflux is broken. The input end of the booster pump is connected with the mixing device, and the output end of the booster pump is connected with the second end of the jet pipe 13, and the booster pump is used for outputting the solid-liquid mixture to the flow field simulation device 1. The input end of self priming pump is connected with the second end of recovery tube 14, and the output is connected with the compounding device for export the solid-liquid mixture to the compounding device, realize the recycle of solid-liquid mixture. Compared with the simulation mode of carrying out jet flow crushing on the solid phase sample in the sealed box body 11, the simulation method can avoid the disturbance of the massive solid phase sample to the flow field, and along with the change of the volume of the solid phase sample, the disturbance degree of the flow field can also change, so that the experimental result is uncontrollable, and therefore the mode of mixing the solid phase and the liquid phase and inputting the mixed solid phase and the liquid phase into the flow field simulation device 1 is adopted.

Specifically, the mixing device comprises a feeder and a mixing tank, wherein solid-phase particles are stored in the feeder, and when the concentration of the solid-phase particles needs to be increased, the solid-phase particles are added into the mixing tank by the feeder, so that the concentration of the solid-phase particles is increased; the mixing tank is connected with the booster pump, and the mixture can be conveyed to the flow field simulation device 1 through the booster pump after the mixing of the mixing tank is completed.

Further, the sealed box 11 includes a sealed box body 111 and end covers 112, the end covers 112 are detachably connected to one end of the sealed box body 111, optionally, the number of the end covers 112 is two, and the two end covers 112 are respectively arranged in one-to-one correspondence with two ends of the sealed box body 111. After the end cap 112 is opened, the dummy tube 12 can be removed from the sealed case 11, thereby facilitating replacement of the dummy tube 12.

Further, the number of the jet holes 131 and the recovery holes 141 is more than two, so that the flow field condition of multi-nozzle combined jet flow crushing can be simulated.

Further, the dummy tube 12 is provided with a first pressure detection means for detecting the influence of the flow field. Preferably, the number of the first pressure detecting devices is multiple, and the first pressure detecting devices are distributed on the inner wall of the simulation tube 12, so that the flow field condition can be simulated more comprehensively and accurately.

Further, a weight sensor is arranged at the bottom of the sealed box body 11 and used for detecting the deposition amount of the solid-phase particles in the sealed box body 11, so that the deposition rate of the solid-phase particles in the sealed box body 11 is calculated, the mixing ratio of the solid and liquid phases in the mixing device and the output power of the booster pump can be adjusted, the concentration of the solid-phase particles in the sealed box body 11 is kept in a certain range, and the experimental result is prevented from being changed due to the change of the concentration of the solid-phase particles. Optionally, the weight sensor may be electrically connected to the mixing device, the booster pump, and the self-priming pump, so as to automatically adjust the concentration of the solid particles in the sealed box 11.

Furthermore, the inner space of the simulation pipe 12 is communicated with the inner space of the sealed box body 11, the sealed box body 11 is provided with overflow valves for preventing the water pressure in the sealed box body 11 from being overhigh, and the simulation device can also be used for simulating the influence on multiphase flow field and solid phase collection in a digging cavity when the wall of the well leaks in the digging cavity, and the number of the overflow valves can be correspondingly increased or decreased according to the requirement.

Further, sealed box 11 is equipped with second pressure measurement, and the quantity of second pressure measurement can increase and decrease as required, and second pressure measurement distributes in sealed box 11 internal surface for the influence of overflow volume flow to flow field when detecting the overflow valve and opening, situation when simulating the wall of a well and revealing better when the excavation chamber appears.

Furthermore, the sealed box body 11 and the simulation tube 12 are made of transparent materials, so that the experiment process can be observed and detected by an experimenter or a visible light detector conveniently.

Based on any one of the natural gas hydrate solid-state fluidization excavation cavity flow field simulation devices, the experimental method in the second aspect of the invention comprises the following steps:

s1, manufacturing a simulation pipe 12, and enabling the roughness, the geometric shape and the geometric dimension of the inner wall of the simulation pipe 12 to be close to the form of a mining cavity to be simulated, so that the simulation precision is improved. Determining the positions of the jet holes 131 and the recovery holes 141 in the sealed box body 11, and the arrangement mode, the geometric shape and the number of the jet holes 131 and the recovery holes 141, so as to simulate the jet flow crushing form of corresponding mining equipment;

s2, arranging a first pressure detection device on the inner wall of the simulation pipe 12;

s3, mounting the simulation pipe 12, the jet pipe 13 and the recovery pipe 14 to the sealed box body 11, sealing the end face of the sealed box body 11, injecting water into the sealed box body 11 to fill the inner space of the sealed box body, checking the sealing performance of the sealed box body 11, and preventing flow field disorder caused by leakage in the experimental process;

s4, starting a mixing device to obtain a solid-liquid phase mixture;

s5, starting a booster pump and a self-priming pump to form a flow field in the sealed box body 11, and recording experimental data of the first pressure detection device;

s6, obtaining the change rate of the weight of the sealed box body 11 along with time according to the real-time weight value of the weight sensor, so as to calculate the deposition rate of solid-phase particles in the sealed box body 11, further adjusting the mixing proportion of the mixing device and the output power of the booster pump, and keeping the concentration of the solid-phase particles in the sealed box body 11 within a set range;

s7, changing at least one of the roughness, the geometric shape and the geometric dimension of the inner surface of the simulation pipe 12, the mixing proportion of the mixing device, the output power of the booster pump, the positions, the number and the sizes of the jet hole 131 and the recovery hole 141 and the overflow critical value of the overflow valve, and repeating the steps from S1 to S6.

While the preferred embodiments of the present invention have been illustrated and described, it will be understood by those skilled in the art that the present invention is not limited to the details of the embodiments shown and described, but is capable of numerous equivalents and substitutions without departing from the spirit of the invention as set forth in the claims appended hereto.