Device and method for cleaning fluid transportation pipeline through natural vibration pulse jet flow

Abstract

The invention belongs to the technical field of pipeline cleaning, and particularly relates to a device and method for cleaning a fluid transportation pipeline through natural vibration pulse jet flow, and the device comprises a supply system, a pressurization system and a cleaning system; the supply system comprises a decompression chamber used for transporting the cleaning system, the pressurization system comprises a fluid conveying pipe and a pressurization pump connected with the fluid conveying pipe, a pressure sensor is arranged on an outlet pipeline of the pressurization pump, and an outlet pipeline of the pressurization pump is communicated with the cleaning system. The invention relates to a novel method and device for completing online cleaning under the condition of not interrupting transportation by combining a jet flow technology of natural vibration pulse and cavitation effect so as to solve the key technical bottleneck problems of discontinuous operation, incomplete cleaning, poor working condition adaptability and the like in the prior art.

Description

Technical Field

[0001] The present invention belongs to the technical field of pipeline cleaning, and in particular relates to a device and method for cleaning a fluid transport pipeline by utilizing a self-oscillating pulse jet. Background Art

[0002] Pipeline transportation, with its advantages of continuity, stability, and low cost, has gradually become the primary method for transporting fluids such as oil, natural gas, and carbon dioxide. As pipelines age, corrosion and impurity deposition within the pipelines lead to increased transport resistance, severely impacting transport efficiency and increasing transportation costs. Therefore, efficient pipeline cleaning technology is crucial.

[0003] Various types of conveying media have put forward higher requirements for the internal cleanliness of the pipeline, such as no sparks, no mixing of other impurities, and no suspension of fluid transportation. Traditional pipeline cleaning technologies are mainly based on water jets, air gouging, mechanical brushing, etc. For example, patent CN112096466A discloses a sewage treatment pipeline cleaning device, which adopts a rotating brush head and high-pressure water flow combined cleaning method; patent CN111536004A discloses a robot for internal pipeline cleanliness detection, which combines image recognition with mechanical scraping for cleaning. However, most of these technologies rely on external power and water resources, and have the following problems: First, the pipeline needs to be stopped for cleaning, which affects the continuous operation of the pipeline; second, the introduction of moisture or other impurities may cause secondary pollution to the transportation system; third, the cleaning depth is limited, and stubborn deposits such as scaling cannot be removed efficiently, and most devices are difficult to adapt to the operating requirements in a high-pressure closed environment.

[0004] In response to the above shortcomings, some studies have attempted to introduce physical means such as jet oscillation and thermal diffusion to improve the cleaning effect. As a new type of enhanced cleaning method, self-oscillating pulse jet has high-frequency impact force, cavitation effect and resonance effect, which can effectively separate the attachment layer from the matrix structure. In the application scenario of pipeline cleaning, there is still a lack of cleaning solutions that can achieve "pressure operation", "no external cleaning medium" and "avoid secondary pollution". The current market and research have defects such as the inability to achieve continuous operation, limited application scenarios, the need for the pipeline to be in an open state, and the introduction of new impurities. A cleaning technology route that can take into account safety, efficiency, greenness and strong adaptability has not yet been formed, and it can no longer meet the needs of efficient cleaning of transportation pipelines in multiple scenarios. Summary of the Invention

[0005] The purpose of the present invention is to provide a device and method for cleaning fluid transport pipelines using self-oscillating pulse jets. By utilizing the own transport medium and combining the jet technology of self-oscillating pulses and cavitation effects, a new method and device are provided to complete online cleaning without interrupting transportation, so as to solve the key technical bottleneck problems existing in the prior art, such as discontinuous operation, incomplete cleaning and poor adaptability to working conditions.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] A device for cleaning fluid transport pipelines using self-oscillating pulse jets includes a supply system, a boosting system, and a cleaning system; the supply system includes a decompression chamber for transporting the cleaning system, the boosting system includes a fluid delivery pipe, a boosting pump connected to the fluid delivery pipe, a pressure sensor is provided on the boosting pump outlet pipe, and the boosting pump outlet pipe is connected to the cleaning system.

[0008] Furthermore, the cleaning system includes a winch and a cleaning device. The winch is provided with a mechanical rotating handle. The cleaning device includes a jet nozzle located in the center and connected to the booster pump outlet pipe, and also includes a centering and straightening mechanism for fixing the jet nozzle. The arrangement of the nozzles in the cleaning device is a key link. The arrangement of the nozzles is specifically shown in Figure 5 The cleaning device is equipped with four rear-mounted Laval nozzles to provide forward driving force, and four front-mounted circumferential Laval nozzles with oscillation cavities to form self-oscillating pulse jets that rotate for cleaning. The oscillation cavity is the key structure for achieving self-oscillating pulse jets. The working principle of the Laval nozzle is that the compressed air in the convergent section increases the gas speed from subsonic to sonic; in the divergent section, the gas expansion further increases the speed, ultimately achieving supersonic speed. The design of the oscillation cavity is key to regulating the expansion and compression process and thermodynamic processes. The expansion and compression process and thermodynamic processes during the movement within the oscillation cavity determine the disturbance and feedback of the vortex structure. The disturbance feedback is adjusted to achieve effective excitation and complete the formation of the self-oscillating pulse jet. During the cleaning process, the self-oscillating pulse jet impacts impurities on the inner wall of the pipe at high speed, with an impact force several times that of traditional cleaning methods, effectively removing impurities attached to the pipe wall. At the same time, because the self-oscillating jet resonates with impurities on the wall, the impurities are loosened, further enhancing the cleaning effect. Furthermore, as the high-speed jet passes through the Laval nozzle and oscillation cavity to form a self-oscillating pulse jet, a low-pressure cavity region forms locally at the nozzle outlet and in the near-field of the wall, inducing a cavitation effect. Cavitation bubbles rapidly form and collapse near the wall, releasing microjets and instantaneous high-pressure pulses, further enhancing the shear damage and impact stripping of the attached layer. The superposition of cavitation and self-oscillating pulses creates a synergistic reinforcement mechanism that not only improves the efficiency of impurity stripping but also expands the cleaning range, offering significant advantages in removing thick scale layers, metal corrosion products, and other stubborn attachments.

[0009] Furthermore, the centering and righting mechanism includes an annular support arm, a plurality of universal wheels are provided on the outer edge of the annular support arm, and the annular support arm is fixedly connected to the central nozzle through a plurality of support rods.

[0010] Furthermore, the jet nozzle includes a connecting portion connected to the boost pump outlet pipeline and an injection portion at the front end. The front end of the injection portion is provided with four circumferential nozzles evenly distributed along the circumference, and also includes four rear nozzles evenly arranged tangentially along the injection portion. The rear nozzles are located behind the circumferential nozzles and their injection direction is opposite to the forward direction of the injection portion. The injection direction of the circumferential nozzles is perpendicular to the center of the injection portion.

[0011] Furthermore, the circumferential nozzle is a Laval nozzle with an oscillation cavity, and its structure includes an upstream Laval nozzle, a middle oscillation cavity and a downstream Laval nozzle. The central axes of the upstream Laval nozzle, the middle oscillation cavity and the downstream Laval nozzle coincide with each other, and the inner diameter of the oscillation cavity is larger than the inner diameter of the upstream Laval nozzle inlet, and the inner diameter of the upstream Laval nozzle inlet is larger than the inner diameter of the downstream Laval nozzle inlet; the nozzle structural parameters directly determine the jet velocity, pulse frequency and cleaning range. The design of the self-excited oscillation nozzle is shown in Figure 2 . Through this self-designed nozzle, it can form Figure 8 The self-oscillating pulse jet shown in Figure 1. According to the simulation and experimental results, a reasonable combination of parameters such as the upstream nozzle throat diameter d, the upstream nozzle outlet diameter d2, the oscillation cavity length L, and the collision wall angle α is the basis for achieving high-frequency and high-amplitude self-oscillating pulse jets. Among them, the design of the oscillation cavity is the key to modulating the pulse frequency, such as Figure 9 and Figure 10 ; A suitable cavity diameter ratio (L / d2) can enhance the peak velocity and pulse amplitude. The optimal match between the upstream nozzle structure and the cavity diameter ratio is as follows: Figure 11 .

[0012] Furthermore, the decompression chamber is a closed chamber with a first door on the top and a second door on the bottom. The first door isolates the cabin environment from the atmospheric environment, and the second door isolates the cabin environment from the transport pipeline. The setting of the decompression chamber can prevent the transport environment of the pipeline from being affected during the cleaning process.

[0013] Furthermore, it also includes a recovery system located at the end of the transportation pipeline, which includes an impurity filter cabin and a detachable collection bin connected thereto. The impurity filter cabin is provided with a pressure relief valve, and the recovery system is connected according to actual use needs.

[0014] Another object of the present invention is to provide a method for cleaning a fluid transport pipeline using a self-oscillating pulse jet, comprising the following steps:

[0015] (1) Introduce low-pressure gas into the device, check the air tightness of each valve and the connection between the jet nozzle and the pipeline, and check whether each pressure gauge can be used normally;

[0016] (2) Connecting the transport pipeline to the cleaning device and winch;

[0017] (3) Place the cleaning device into the decompression chamber that has been decompressed, adjust the pressure of the decompression chamber to the same pressure as the pipeline, connect the second door of the decompression chamber to the inlet of the pipeline, open the second door, and transport the cleaning device to the pipeline to be cleaned;

[0018] (4) Connect the fluid delivery pipe to the transport pipeline, then turn on the booster system and observe the pressure sensor. When the pressure reaches the specified pressure, the circumferential nozzle forms a self-oscillating pulse jet as a cleaning jet, and the rear nozzle forms a continuous jet to provide forward driving force, and the cleaning operation is carried out continuously;

[0019] (5) Use pipeline inspection equipment to check the cleaning effect and adjust the jet pressure if necessary;

[0020] (6) After the cleaning operation is completed, turn off the booster pump, turn the mechanical rotary handle to drive the winch to return the cleaning device to the decompression chamber, depressurize the decompression chamber, and remove the cleaning device;

[0021] (7) Open the impurity filter cabin to collect the impurities that fall off the pipeline during the cleaning operation and carry out centralized treatment;

[0022] (8) Maintain the device to facilitate the next cleaning operation.

[0023] The calculation process in cabin design is as follows:

[0024] The wall thickness of the cabin is calculated using the corresponding pressure calculation formula, namely formula (1).

[0025]

[0026] Where: t is the wall thickness; p0 is the design pressure; d is the inner diameter of the cylinder; [σ] is the allowable stress of the material; ——Welding joint coefficient.

[0027] Taking the safety factor into consideration, the wall thickness is determined according to the allowable stress of the material. The allowable stress is calculated as shown in formula (2).

[0028]

[0029] Where: s ——material yield strength; n——safety factor.

[0030] The stable pressure provided by the booster pump, combined with the jet nozzle structure, can continuously output high-speed self-oscillating pulse jets, achieving a combined effect of high-frequency impact, cavitation, and resonance, significantly enhancing cleaning efficiency. The specific calculation formulas are shown in Equations (3) to (8).

[0031] Assume the ambient pressure in the transport pipeline is P env, ambient fluid velocity v env , high-pressure pump outlet speed v1.

[0032] The high-pressure pump forms a jet at the nozzle after experiencing pressure loss along the way and local pressure loss, as shown in formula (3).

[0033] P2=P pump -ΔP friction -ΔP local (3)

[0034] Where: P2 - jet pressure, MPa; P pump ——High-pressure pump set pressure, MPa; ΔP friction ——Pressure loss along the way, MPa; ΔP local ——Local pressure loss, MPa.

[0035] The pressure loss along the way can be calculated using the Darcy-Weisbach equation, as shown in equation (4).

[0036]

[0037] Where: f is the friction factor, dimensionless; L is the length of the pipe, m; D is the inner diameter of the pipe, mm; ρ is the fluid density, kg / m 3 .

[0038] The local pressure loss can be calculated using formula (5):

[0039]

[0040] Where: K is the local resistance coefficient, dimensionless.

[0041] According to Bernoulli equation (6)

[0042]

[0043] The cavitation number σ is a dimensionless parameter used to describe the relationship between the local pressure and the saturated vapor pressure in the fluid, as shown in Equation (7). If σ is small (for example, σ < 0.1), it indicates that cavitation is likely to occur and the erosion ability is strong. Let σ = 0.05.

[0044]

[0045] Where: v rel ——Relative velocity of fluid, m / s.

[0046] v rel =v2-v env (8)

[0047] The advantages of the present invention are:

[0048] 1. For the first time, self-excited oscillation pulse jet technology was introduced into pipeline cleaning: a jet with high impact force, high-frequency pulses, and cavitation effect was formed, which can effectively remove stubborn deposits such as carbonate crystals and rust;

[0049] 2. A cleaning device with a centering mechanism is designed to ensure that the cleaning nozzle is always located in the center of the pipe, thereby improving energy efficiency and cleaning effect;

[0050] 3. Use the transported medium as the cleaning source to achieve green operation: the fluid transported in the pipeline is used as the cleaning medium, without the need to introduce additional water or chemical reagents, thus avoiding secondary pollution;

[0051] 4. Capable of online operation: The double-sealed decompression chamber structure enables cleaning operations to be carried out without interrupting transportation, significantly reducing economic losses caused by transportation stoppages;

[0052] 5. Adopting a special Laval nozzle and oscillation cavity combination structure: forming a stable self-excited oscillation structure, the jet has good supersonic characteristics, and enhances the jet energy transfer and impurity stripping capabilities;

[0053] 6. Modular structure facilitates system maintenance and reuse: including cleaning device, impurity filter cabin, etc. are all detachable structures, which is convenient for daily maintenance and system upgrades. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 It is a structural schematic diagram of the self-oscillating pulse jet cleaning device of the present invention.

[0055] Figure 2 This is the design diagram of the circumferential nozzle in the present invention, wherein the upstream nozzle throat diameter d; the upstream nozzle inlet diameter d1; the upstream nozzle outlet diameter d2; the oscillation cavity length L; the oscillation cavity diameter D; the collision wall angle α; and the downstream nozzle inlet diameter d3.

[0056] Figure 3 It is a schematic structural diagram of the cleaning device of the present invention.

[0057] Figure 4 This is a schematic diagram of the cleaning device placed in the decompression chamber.

[0058] Figure 5 It is a schematic diagram of the three-dimensional structure of the injection portion in the cleaning device of the present invention.

[0059] Figure 6 It is a schematic diagram of the three-dimensional structure of the axial section in the cleaning device.

[0060] Figure 7 It is a schematic diagram of the three-dimensional structure of the radial section in the cleaning device.

[0061] Figure 8 This is a diagram of the self-oscillating pulse jet formed by the circumferential nozzle in the present invention.

[0062] Figure 9 It is the frequency of self-oscillating pulse jet under different oscillation cavity length conditions when d2=2.5mm.

[0063] Figure 10 is the self-oscillating pulse jet frequency under different upstream nozzle outlet diameter conditions when L=6mm.

[0064] Figure 11 It is the optimal matching relationship diagram between upstream nozzle structure and cavity diameter ratio. DETAILED DESCRIPTION

[0065] Example

[0066] like Figure 1-11 As shown, a device for cleaning a fluid transport pipeline using a self-oscillating pulse jet comprises a supply system, a pressurizing system and a cleaning system; the supply system comprises a decompression chamber 9 for transporting the cleaning system, the pressurizing system comprises a fluid delivery pipe 1, a booster pump 4 connected to the fluid delivery pipe, a pressure sensor 5 is provided on the booster pump outlet pipe, and the booster pump outlet pipe is connected to the cleaning system; the cleaning system comprises a winch 6 and a cleaning device 8, the winch is provided with a mechanical rotating handle, the cleaning device comprises a jet nozzle located in the center and connected to the booster pump outlet pipe, and also comprises a centering straightening mechanism for fixing the jet nozzle. The arrangement of the nozzles in the cleaning device is a key link, and the arrangement of the nozzles is specifically shown in FIG. Figure 5The cleaning device is equipped with four rear-mounted Laval nozzles to provide forward driving force, and four front-mounted circumferential Laval nozzles with oscillation cavities to form self-oscillating pulse jets that rotate for cleaning. The oscillation cavity is the key structure for achieving self-oscillating pulse jets. The working principle of the Laval nozzle is that the compressed air in the convergent section increases the gas speed from subsonic to sonic; in the divergent section, the gas expansion further increases the speed, ultimately achieving supersonic speed. The design of the oscillation cavity is key to regulating the expansion and compression process and thermodynamic processes. The expansion and compression process and thermodynamic processes during the movement within the oscillation cavity determine the disturbance and feedback of the vortex structure. The disturbance feedback is adjusted to achieve effective excitation and complete the formation of the self-oscillating pulse jet. During the cleaning process, the self-oscillating pulse jet impacts impurities on the inner wall of the pipe at high speed, with an impact force several times that of traditional cleaning methods, effectively removing impurities attached to the pipe wall. At the same time, because the self-oscillating jet resonates with impurities on the wall, the impurities are loosened, further enhancing the cleaning effect. In addition, in the process of high-speed jet passing through the Laval nozzle and oscillation cavity to form a self-oscillating pulse jet, a low-pressure cavity area will be formed locally at the nozzle outlet and the near field of the wall, thereby inducing the formation of a cavitation effect. Cavitation bubbles are rapidly generated and collapsed near the wall, releasing microjets and instantaneous high-pressure pulses, further enhancing the shear damage and impact stripping of the attached layer. The superposition of cavitation and self-oscillating pulses produces a synergistic reinforcement mechanism, which not only improves the efficiency of impurity stripping, but also can expand the scope of cleaning, especially in removing thick scale layers, metal corrosion products and other stubborn attachments. It has significant advantages; the centering straightening mechanism includes an annular support arm 15, the outer edge of the annular support arm is provided with a plurality of universal wheels, and the annular support arm is fixedly connected to the central jet nozzle through a plurality of support rods; the jet nozzle includes a connecting portion connected to the boost pump outlet pipeline and a front end injection portion, the front end of the injection portion is provided with four circumferential nozzles 20 evenly distributed along the circumference, and also includes four rear nozzles 21 evenly arranged along the tangent direction of the injection portion, the rear nozzles 21 are arranged The nozzle is located at the rear of the circumferential nozzle and its spray direction is opposite to the forward direction of the spray part, and the spray direction of the circumferential nozzle is perpendicular to the center of the spray part; the circumferential nozzle is a Laval nozzle with an oscillation cavity, and its structure includes an upstream Laval nozzle, a middle oscillation cavity and a downstream Laval nozzle. The central axes of the upstream Laval nozzle, the middle oscillation cavity and the downstream Laval nozzle coincide, and the inner diameter of the oscillation cavity is larger than the inner diameter of the upstream Laval nozzle inlet, and the inner diameter of the upstream Laval nozzle inlet is larger than the inner diameter of the downstream Laval nozzle inlet; the nozzle structural parameters directly determine the jet velocity, pulse frequency and cleaning range. The self-excited oscillation nozzle, that is, the jet nozzle design, see Figure 2 . Through this self-designed nozzle, it can form Figure 8The self-oscillating pulse jet shown in Figure 1. According to the simulation and experimental results, a reasonable combination of parameters such as the upstream nozzle throat diameter d, the upstream nozzle outlet diameter d2, the oscillation cavity length L, and the collision wall angle α is the basis for achieving high-frequency and high-amplitude self-oscillating pulse jets. Among them, the design of the oscillation cavity is the key to modulating the pulse frequency, such as Figure 9 and Figure 10 ; A suitable cavity diameter ratio (L / d2) can enhance the peak velocity and pulse amplitude. The optimal match between the upstream nozzle structure and the cavity diameter ratio is as follows: Figure 11 ; The decompression chamber is a closed chamber, with a first hatch 18 provided on the top of the decompression chamber and a second hatch 19 provided on the bottom of the decompression chamber, wherein the first hatch isolates the cabin environment from the atmospheric environment, and the second hatch isolates the cabin environment from the transport pipeline. The setting of the decompression chamber can not affect the transport environment of the pipeline during the cleaning process; it also includes a recovery system at the end of the fluid delivery pipe 1, the recovery system includes an impurity filter chamber 12 and a detachable collection bin 14 connected thereto, and a pressure relief valve 13 is provided on the impurity filter chamber, and the recovery system is connected according to actual use needs; wherein the filter screen 11 is a filter screen provided in the pipe section, which is used to clean the fixed pipe section to meet the requirements of pipeline cleaning. If the pipe section does not have a built-in filter screen, it does not affect the normal use and cleaning effect of the cleaning device.

[0067] Application Examples

[0068] The following will describe in detail the specific implementation process of the device and method for cleaning a fluid transport pipeline using a self-oscillating pulse jet according to the present invention, taking a carbon dioxide transport pipeline as an example.

[0069] Preliminary preparation: Before cleaning, conduct a comprehensive inspection of the carbon dioxide transport pipeline, including pipeline integrity and valve sealing. Connect the self-oscillating pulse jet cleaning device according to the drawings and design requirements, ensuring that the jet generator and pipeline connectors, such as the stop valve 2, quick connector 3, and ball valve 7, are well sealed. Inject low-pressure gas into the system and check all connections for leaks to ensure that no leaks occur under the high-pressure environment of carbon dioxide.

[0070] System startup and cleaning: Open the pressure relief valve 10 of the decompression chamber 9 to release pressure, allowing the chamber's internal pressure to equalize with atmospheric pressure. Once this equilibrium is achieved, open the first hatch 18 of the decompression chamber 9, which faces the atmospheric environment, and advance the cleaning device 8 to the designated position within the chamber. Then, close this first hatch 18 and open the second hatch 19 connecting the chamber to the CO2 transport pipeline 1. The cleaning device 8 then enters the pipeline. After closing this second hatch 19, the system is ready.

[0071] Start the CO2 supply system, extracting CO2 from the CO2 transport pipeline 1. Open the shutoff valve 2 and connect the inlet pipe of the booster pump 4 to the quick-connect connector 3. Start the booster system, and the high-pressure pump 4 pressurizes the CO2 to the specified pressure. The CO2 flows through the cleaning pipeline, capstan 6, and ball valve 7, reaching the cleaning device 8. The ball valve 7 ensures a uniform and continuous flow of CO2. Upon entering the cleaning device 8, the CO2 forms four self-oscillating pulsed jets 16 at the circumferential nozzle 19 and a continuous jet 17 at the rear nozzle 21.

[0072] Cleaning effect monitoring: During the cleaning process, pipeline inspection equipment is used to monitor the cleaning effect. For example, use a pipeline endoscope to check the cleanliness of the inner wall of the pipeline every hour, compare the images before and after cleaning, and judge the removal of dirt. If it is found that there is still a lot of dirt remaining, adjust the pressure of the jet to enhance the cleaning ability of the jet. In the actual cleaning process, with the help of high-frequency pulse jets and local cavitation at the outlet of the Laval nozzle, the system realizes a dual-enhanced cleaning mechanism. The cavitation bubbles induced by high-speed airflow collapse near the wall surface, instantly converting local kinetic energy into high-frequency impact, which produces a stronger scouring, shearing and peeling effect on the attached scale layer and sediment. Experimental verification shows that under the same pressure conditions, the self-oscillating pulse jet with superimposed cavitation effect has a significantly better cleaning depth and area than the simple self-oscillating jet.

[0073] After cleaning is completed:

[0074] When the in-pipe inspection system detects that the cleaning device cleaning operation is complete, turn off the booster pump 4, rotate the winch 6 by rotating the handle to pull the cleaning device 8, open the second hatch 19 of the decompression chamber 9, allow the cleaning device 8 to enter the decompression chamber, close the second hatch 19, open the pressure relief valve 10 to balance the pressure in the decompression chamber with the atmospheric pressure, open the first hatch 18, remove the cleaning device 8, and complete the cleaning operation. Open the hatch where the impurity filter chamber 12 connects to the carbon dioxide pipeline 1, close the hatch, and open the pressure relief valve 13. When the pressure in the chamber is balanced with the atmospheric pressure, the detachable collection device at the bottom of the chamber can be removed to centrally process the impurities.

[0075] The collected dirt is sorted and processed. If the dirt contains recyclable components, such as certain metal impurities, it can be recycled using appropriate recycling processes. Non-recyclable dirt is properly landfilled or disposed of in a harmless manner in accordance with environmental protection requirements. At the same time, the cleaning equipment is maintained and serviced, and wear and tear of various equipment is checked. Consumable parts, such as stop valves, pressure relief valves, and ball valves, are replaced to prepare for the next cleaning operation.

Claims

1. A device for cleaning a fluid transport pipeline using a self-oscillating pulse jet, characterized in that: It includes a supply system, a boosting system and a cleaning system; the supply system includes a decompression chamber for transporting the cleaning system, the boosting system includes a fluid delivery pipe, a boosting pump connected to the fluid delivery pipe, a pressure sensor is provided on the boosting pump outlet pipe, and the boosting pump outlet pipe is connected to the cleaning system.

2. The device for cleaning a fluid transport pipeline using a self-oscillating pulse jet according to claim 1, characterized in that: The cleaning system includes a winch and a cleaning device. The winch is provided with a mechanical rotating handle. The cleaning device includes a jet nozzle located in the center and connected to the booster pump outlet pipeline, and also includes a centering straightening mechanism for fixing the jet nozzle.

3. The device for cleaning a fluid transport pipeline using a self-oscillating pulse jet according to claim 2, characterized in that: The centering and straightening mechanism comprises an annular support arm, a plurality of universal wheels are provided on the outer edge of the annular support arm, and the annular support arm is fixedly connected to the central nozzle through a plurality of support rods.

4. The device for cleaning a fluid transport pipeline using a self-oscillating pulse jet according to claim 3, wherein: The jet nozzle includes a connecting portion connected to the boost pump outlet pipeline and an injection portion at the front end. The front end of the injection portion is provided with four circumferential nozzles evenly distributed along the circumference, and also includes four rear nozzles evenly arranged along the tangential direction of the injection portion. The rear nozzles are located behind the circumferential nozzles and their injection direction is opposite to the forward direction of the injection portion. The injection direction of the circumferential nozzles is perpendicular to the center of the injection portion.

5. The device for cleaning a fluid transport pipeline using a self-oscillating pulse jet according to claim 4, characterized in that: The circumferential nozzle is a Laval nozzle with an oscillation cavity, and its structure includes an upstream Laval nozzle, a middle oscillation cavity and a downstream Laval nozzle. The central axes of the upstream Laval nozzle, the middle oscillation cavity and the downstream Laval nozzle coincide, and the inner diameter of the oscillation cavity is larger than the inner diameter of the upstream Laval nozzle inlet, and the inner diameter of the upstream Laval nozzle inlet is larger than the inner diameter of the downstream Laval nozzle inlet.

6. The device for cleaning a fluid transport pipeline using a self-oscillating pulse jet according to claim 5, characterized in that: The decompression chamber is a sealed chamber, a first hatch is provided on the top of the decompression chamber, and a second hatch is provided on the bottom of the decompression chamber.

7. The device for cleaning a fluid transport pipeline using a self-oscillating pulse jet according to claim 6, characterized in that: It also includes a recovery system located at the end of the transport pipeline, which includes an impurity filter cabin and a detachable collection cabin connected thereto, and a pressure relief valve is provided on the impurity filter cabin.

8. The method for cleaning the device according to any one of claims 1 to 7, characterized in that: The following steps are involved: (1) Introduce low-pressure gas into the device, check the air tightness of each valve and the connection between the jet nozzle and the pipeline, and check whether each pressure gauge can be used normally; (2) Connecting the transport pipeline with the cleaning device and winch; (3) Place the cleaning device into the decompression chamber that has been decompressed, adjust the pressure of the decompression chamber to the same as the pressure of the transport pipeline, connect the second door of the decompression chamber to the inlet of the transport pipeline, open the second door and transport the cleaning device to the transport pipeline to be cleaned; (4) Connect the fluid delivery pipe to the transport pipeline, then turn on the booster system and observe the pressure sensor. When the pressure reaches the specified pressure, the circumferential nozzle forms a self-vibrating pulse jet as a cleaning jet, and the rear nozzle forms a continuous jet to provide forward driving force, and the cleaning operation is carried out continuously; (5) Use pipeline inspection equipment to check the cleaning effect and adjust the jet pressure if necessary; (6) After the cleaning operation is completed, turn off the booster pump, turn the mechanical rotary handle to drive the winch to return the cleaning device to the decompression chamber, depressurize the decompression chamber, and remove the cleaning device; (7) Open the impurity filter cabin, collect the impurities in the pipeline that fall off during the cleaning operation, and carry out centralized treatment; (8) Maintain the device to facilitate the next cleaning operation.

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