Anti-shearing small-scale loop turbulence resistance reduction evaluation device

Abstract

The invention relates to the field of turbulence control in fluid mechanics, and discloses an anti-shearing small-scale loop turbulence resistance reduction evaluation device. The device comprises a gas pressure supply system, a turbulence circulation test system, a telescopic pipe reducing resistance reduction evaluation system, a polymer drag reducer adding system, a waste liquid recycling and sampling system and a data acquisition system. According to the device, nitrogen is adopted as a power source, the turbulent shear resistance is enhanced through a magnetic force induction mechanism, an anti-shear two-way reciprocating pump is driven through a magnetic force induction technology, damage of mechanical shear of a traditional centrifugal pump to a polymer drag reducer is avoided, and the stability of the drag reducer in a turbulent flow environment is accurately evaluated; the pipe diameter of a loop is regulated and controlled in real time through a telescopic pipe reducing resistance reduction evaluation system, and quantitative evaluation of the resistance reduction effect under the pipe diameter changing condition is achieved. By applying the device disclosed by the invention, the turbulence drag reduction performance evaluation, the anti-shearing performance evaluation and the pipe diameter effect evaluation of the polymer drag reducer under the condition of the reciprocating pump can be efficiently completed.

Description

Technical Field

[0001] This invention relates to the field of turbulence control in fluid mechanics, specifically to a shear-resistant small-scale loop turbulence drag reduction evaluation device. Background Technology

[0002] Turbulence is a complex, multi-scale, irregular flow phenomenon where fluids experience significant energy dissipation under intense turbulent disturbances. To reduce turbulent energy dissipation during refined oil transportation, a common method is to add a very small amount of polymer drag-reducing agent to the pipeline. However, this polymer drag-reducing agent is subject to blade shearing under centrifugal pump conditions, which can negate its drag-reducing effect. Therefore, there is an urgent need to develop a shear-resistant, small-scale annular turbulence drag reduction evaluation device to mitigate shear failure in the polymer drag-reduction process.

[0003] Currently, existing methods for reducing drag in refined oil pipelines involve adding different polymer molecules to regulate the fluid's microstructure and reduce flow resistance. Existing in-pipe drag reduction experiments primarily evaluate the drag reduction efficiency of additives by testing the change in pressure difference before and after additive injection. However, the following shortcomings exist in evaluating drag reduction during refined oil transportation: (1) The drag reduction effect of drag reducers is mainly due to the long molecular chain suppressing the additional stress of turbulence, thereby weakening and dissolving turbulent vortices and suppressing radial pulsation. Among them, the longer the molecular backbone, the more obvious the drag reduction effect, but at the same time, it is more easily sheared. Once sheared and degraded, the drag reduction performance will be significantly reduced, and this result is permanent and irreversible.

[0004] (2) The pipe diameter parameters of traditional loop device are fixed and cannot be adjusted after installation, which makes it impossible to flexibly compare the fluid dynamic characteristics under different pipe diameter conditions in the same experimental system, which seriously restricts multivariate correlation analysis and optimization verification. Summary of the Invention

[0005] The purpose of this invention is to provide a shear-resistant small-scale loop turbulent flow drag reduction evaluation device, which minimizes the impact of the failure of polymers due to blade shearing during transport by traditional centrifugal pumps, so that the indoor experimental test results of drag-reducing agents are close to the actual flow drag reduction effect between stations in long-distance pipelines, thereby realizing the drag reduction performance evaluation and shear resistance performance evaluation of drag-reducing agents in turbulent flow of long-distance pipelines.

[0006] To achieve the above objectives, the present invention provides a shear-resistant small-scale loop turbulence drag reduction evaluation device, comprising a gas pressure supply system, a turbulence circulation test system, a telescopic tube diameter change drag reduction evaluation system, a polymer drag reduction agent addition system, a waste liquid recovery and sampling system, and a data acquisition system.

[0007] The gas pressure supply system includes a 50 L nitrogen cylinder (1), a pressure reducing valve (2), check valves (3), (26), and (28), a gate valve (4), a three-way valve (27), and a loop device. The internal pressure of the 50 L nitrogen cylinder (1) is 12.5 MPa, and the outlet is connected by a steel cylinder adapter. The pressure reducing valve (2) and the check valve (3) are connected in parallel, with one end connected to the outlet of the nitrogen cylinder and the other end connected to the gate valve (4). The check valves (26) and (28) are installed before the stainless steel pipe is connected to the loop device. The stainless steel pipe is connected to the loop device by welding. The gas is discharged and the pressure is controlled again by adjusting the three-way valve (27).

[0008] The turbulent circulation test system includes a 100 L storage tank (6), a magnetically induced anti-shear bidirectional reciprocating pump (9) and a matching adjustable speed motor, check valves (8), (10), (26), (28), a temperature sensor (20), a turbine flow meter (16), gate valves (7), (22), (24), pressure sensors (5), (17), (21), (25), a telescopic pipe (23), and an experimental loop. The telescopic pipe is connected in series to the circulation pipe section at a distance of more than 10 m from the outlet of the magnetically induced anti-shear bidirectional reciprocating pump (9). The purpose is to ensure that the finished oil can fully develop into a turbulent state before entering the experimental loop.

[0009] The telescopic tube diameter reduction and drag reduction evaluation system comprises an outer tube (40), an inner tube (41), an innermost tube (42), a seal (43), and a telescopic rod (44). The outer tube (40) has a diameter of 500 mm, and the innermost tube (42) has a diameter of 50 mm (the connection ratio can be determined according to experimental requirements). The inner tube (41) and the outer tube (40) are two relatively movable cylindrical pipes, and a seal (43) is provided at their connection to prevent liquid or gas leakage. The telescopic rod (44) is the load-bearing element connecting the inner tube (41) and the outer tube (40). It is equipped with a signal receiving device and connected to a computer system. The movement of the telescopic rod (44) is controlled by the computer to achieve the purpose of adjusting the telescopic tube. The telescopic tube is composed of two symmetrical and identical telescopic tubes linked together. Each telescopic tube consists of multiple sections. The two outer tubes (40) are seamlessly connected to the ring track, and the innermost tubes (42) of the two telescopic tubes are seamlessly connected to each other, so that the two telescopic tubes move together. The inner tube (41) and outer tube (40) move relative to each other through the telescopic movement of the telescopic rod (44). The desired pipe diameter or the conditions for diameter changes during the experiment are input into the computer. The telescopic rod (44) receives system commands and elongates or shortens, controlling the required annular dimension, thus causing relative displacement between the inner tube (41) and outer tube (40). The relative movement of the inner tube (41) and outer tube (40) and the interaction between the two telescopic tubes change the annular dimension. The pressure drop changes of turbulence under different telescopic tube diameters are obtained on the computer, and data analysis is performed. The drag reduction rate formula is used to calculate the drag reduction effect of the turbulence.

[0010] The magnetically induced anti-shear bidirectional reciprocating pump includes a position sensor (31), an electromagnetic coil winding (32), a piston (33), a piston rod (34), a connecting rod (35), a motor spindle (36), a motor (37), an outer cavity (38), and an inner cavity (39). The pump body is a horizontal reciprocating pump. The shaft passes through the end cover, with one end extending out of the pump casing and connecting to the piston. The other end is connected to the motor via the shaft. The piston is driven by the motor to reciprocate within the cylinder, resulting in volume changes that cause pressure changes within the cavity, thereby altering the pressure transmitted to the liquid. The cylinder is cylindrical and made of ductile iron. An amorphous thin film is prepared on its inner wall to ensure the wear resistance of the piston during continuous operation and increase its service life. The specific process is as follows: When the piston (33a) of the magnetically induced anti-shear bidirectional reciprocating pump moves from the right end to the left end, the liquid enters the pump body cavity (39a) from the ring channel, while the solution in the outer cavity (38a) flows out of the pump body. When the piston reaches the left end, the position sensor (31) senses and realizes the change of current direction, thereby realizing the reversal of the magnetic field generated inside the coil, allowing the polymer to be arranged in an orderly manner, reducing the shearing effect of the magnetically induced anti-shear bidirectional reciprocating pump on the drag-reducing agent. At the same time, when the piston (33b) of the magnetically induced anti-shear bidirectional reciprocating pump moves from the left end to the right end, the liquid flows from the pump body cavity (39b) to the outer cavity (38b). The piston moves back and forth in a sinusoidal cycle, with the starting points differing by 1 / 2 cycle. The piston movement cycle is determined by the motor speed.

[0011] The polymer drag reducer addition system includes a storage tank (11), check valves (13) and (15), a gate valve (12), a plunger pump (14), and an experimental loop for injecting pure solvent and polymer drag reducer.

[0012] The waste liquid recovery and sampling system includes a storage tank (18), a gate valve (19), and an experimental loop, which, together with the above-mentioned turbulent circulation test system, realizes the recovery and sampling of test oil. The lower end of the storage tank is equipped with a sampling port, which facilitates the sampling and testing of the experimental solution.

[0013] The data acquisition system includes pressure sensors (5), (17), (21), and (25), a temperature sensor (20), a turbine flow meter (16), a data acquisition unit (29), and a computer (30). Pressure sensors (5), (17), (21), and (25) are installed along the pipeline to monitor the pressure changes of the experimental solution in the loop. The computer (30) monitors and records parameters such as time, pressure, temperature, and flow rate in real time, thereby realizing the evaluation of the turbulent drag reduction performance, shear resistance performance, and pipe diameter effect of the polymer drag reducing agent under reciprocating pump conditions. Attached Figure Description

[0014] Figure 1This is a schematic diagram of the turbulence drag reduction loop device described in this invention; In the diagram: 1-Nitrogen cylinder; 2-Pressure reducing valve; 3, 8, 10, 13, 15, 26, 28-Check valves; 4, 7, 12, 19, 22, 24-Gate valves; 5, 17, 21, 25-Pressure sensors; 6, 11, 18-Storage tanks; 9, 14-Magnetic-induced anti-shear bidirectional reciprocating pumps; 16-Turbine flow meter; 20-Temperature sensor; 23-Expansion joint; 27-Three-way valve; 29-Data acquisition unit; 30-Computer; Figure 2 This is a schematic diagram of the magnetically induced anti-shear type dual-chamber reciprocating pump device according to the present invention; In the diagram: 31-Position sensor; 32-Electromagnetic coil winding; 33-Piston; 34-Piston rod; 35-Connecting rod; 36-Motor spindle; 37-Motor; 38-Outer cavity; 39-Inner cavity; Figure 3 This is a schematic diagram of the structure of the telescopic pipe diameter reduction and drag reduction testing device described in this invention. In the diagram: 40 - outer tube; 41 - inner tube; 42 - innermost tube; 43 - seal; 44 - telescopic rod. Detailed Implementation

[0015] To better understand the present invention, the present invention will be further described in detail below through embodiments, but this should not be construed as limiting the scope of the present invention to the following examples.

[0016] Example 1: The purpose is to evaluate the drag reduction performance of polymer drag reducers on solvent turbulent flow using this test loop. Under constant flow rate and temperature, the drag reduction rate of the drag reducer sample on solvent turbulent flow is calculated by measuring the pressure difference at different pressure sensors before and after the addition of the agent.

[0017] Formula for calculating drag reduction rate:

[0018] in, ΔP N , ΔP P The pressure difference between the pure solvent and the polymer solution before and after the expansion tube (23) is expressed in Pa.

[0019] Operating steps: Purge the gas in the loop device: Close the storage tanks (6#), (11#), (18#) and the gate valves (7), (12), (19) in front of the tanks, open the gate valves (4), (22), (24) and the three-way valve (27), connect the telescopic tube (23) to the experimental loop to form a passage, slowly open the nitrogen cylinder (1), observe the pressure reading on the nitrogen cylinder and use the pressure reducing valve (2) to adjust the pressure to 0.25 MPa and continue for 10 minutes, and then complete the purging of the experimental loop before the experiment.

[0020] Add finished oil: Put 80L of finished oil into the storage tank (6#), close the nitrogen cylinder (1) and the pressure reducing valve (2) and gate valve (4) connected in series with the nitrogen cylinder, close the three-way valve (27), open the storage tank (6) and the valve (9) in front of the oil storage tank, so that the finished oil circulates in the loop device.

[0021] Adding polymer drag reducer: After the finished oil completely fills the entire loop device, close the storage tank (6) and the gate valve (9) connected in series with it, start the motor (37), and the motor main shaft (36) starts to rotate at a constant speed, transmitting force to the piston rod (34) through the connecting rod (35), so that the piston (33) starts to reciprocate. Under the action of the piston, the finished oil begins to flow in the loop, and the speed is gradually increased to make the flow of the finished oil in the loop become turbulent, and its flow is tested. After the finished oil experiment is completed, open the gate valve (19), and the finished oil is recovered to the recovery tank (18#), and the loop is purged according to the purging system described above. After the purging is completed, a certain concentration of polymer drag reducer solution is added to the storage tank (11). The drag reduction experiment after adding the agent is the same as the pure solvent test experiment. During the experiment, after the data from the turbine flow meter (16) remained constant, the pressure values ​​of the pressure sensors (21) and (25) were observed to see if there were any large fluctuations. Real-time data was collected through the data receiver (29) and transmitted to the computer (30) to obtain the pressure difference of the test pipe section before and after the addition of the additive. ΔP P ΔP N .

[0022] Data processing: The computer (30) records the experimental data while the motor (37) is turned on. After the experiment, the experimental data is retrieved from the software database and processed and analyzed using the pre-set drag reduction rate calculation formula to evaluate the drag reduction performance of the drag reducing agent in turbulent flow.

[0023] Example 2: The purpose is to evaluate the shear resistance of the drag-reducing agent using this test loop. While maintaining a constant flow rate and temperature, the drag-reducing agent solution is flowed in the loop for a period of time. t 1. Test its turbulence drag reduction efficiency at a specific time; make the magnetically induced anti-shear bidirectional reciprocating pump operate for the same amount of time, in t Its turbulence drag reduction efficiency was tested at time 2.

[0024] By collecting pressure values ​​at different times, the drag reduction rate of the polymer on solvent turbulence can be calculated, and the decreasing law of drag reduction rate can be simulated and observed, thereby analyzing the shear resistance of the drag-reducing agent sample.

[0025] Deg(t) = [1-DR] deg (t1) / DR deg (t2)×100%

[0026] in, DR deg ( t 1), DR deg ( t 2) Under the same experimental test conditions t 1, t Turbulent drag reduction efficiency measured at time 2.

[0027] Operating steps: The drag-reducing agent shear resistance evaluation experiment can be conducted after the drag reduction experiment following the addition of the agent in Example 1. After the polymer drag reduction experiment data is collected, a cyclic experiment is continued, with the same steps as in Example 1. The difference is that the polymer action is carried out for a period of time under non-magnetic induction and another period under magnetic induction conditions, resulting in different turbulent drag reduction efficiencies. Data processing in Example 2 uses the aforementioned shear degradation rate formula to calculate and evaluate the shear resistance of the added drag-reducing agent sample.

[0028] Example 3: The purpose is to conduct an evaluation experiment on the turbulent drag reduction effect of the pipe diameter using this test loop. While maintaining a constant flow rate and temperature, the expansion ratio of the expansion tube (23) is changed, allowing the finished oil with added drag-reducing agent to circulate multiple times in loops with different expansion tube diameters, thereby simulating the effect of pipe diameter changes on turbulent drag reduction efficiency in long-distance pipelines. Pressure values ​​before and after the drag-reducing agent sample passes through different expansion tube diameters are collected, allowing the calculation of the turbulent drag reduction rate at different expansion tube diameters. The variation of the drag reduction rate with the expansion tube diameter is observed, thus analyzing the drag reduction effect of the drag-reducing agent sample in different expansion tube diameters.

[0029] Formula for calculating drag reduction rate:

[0030] in, ΔP N , ΔP P The pressure difference between the pure solvent and the polymer solution before and after the expansion tube (23) is expressed in Pa.

[0031] Operating steps: Following the shear resistance evaluation experiment of the drag-reducing agent in Example 2, after the polymer drag reduction experiment data was collected, a cyclic experiment was continued, with the steps being the same as in Example 1. The difference is that in this example, a computer (30) is used to send instructions to control the telescopic rod (44) to adjust the telescopic ratio of the telescopic tube, and the pressure drop changes of turbulence under different telescopic tube diameters can be obtained on the computer for data analysis. The data processing of Example 3 uses the above-mentioned drag reduction rate formula for calculation, thereby evaluating the drag-reducing agent sample's effect on turbulent drag reduction in different telescopic tube diameters.

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] It is worth noting that, in the description of the present invention, it should be understood that the indicated orientations or positional relationships, such as "up," "down," "left," and "right," are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the structure or element referred to must have such a specific orientation or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0034] This invention provides three technical solutions: The first type is a magnetically induced anti-shear technology based on a reciprocating pump. The inner cavity (39) is tightly fitted with the position sensor (31), the piston rod and the connecting rod are connected by M6X20 bolts, the connecting rod (35) and the motor spindle (36) are connected by a square clamp, the electromagnetic coil winding with a variable magnetic field is wrapped in the outer cavity, and the current of the electromagnetic coil winding is controlled by an external circuit. The inlet pipe and the outlet pipe are connected to the inner cavity through end caps.

[0035] The second method is electromagnetic directional control of drag-reducing agent arrangement technology. This invention achieves current on / off control of the electromagnetic coil winding (20) by connecting an external circuit. By adjusting the external circuit to control the on / off action of the electromagnetic coil winding (20) and the current direction, the direction of the magnetic field of the electromagnetic device can be changed, thereby causing the polymer molecules to arrange in an orderly manner.

[0036] The third type is the evaluation technology for reducing drag by changing the diameter of a telescopic pipe. The outer tube (40) of the telescopic pipe is seamlessly connected to the loop device through a seal (43), forming an integral part with the turbulent drag reduction loop device; the outer tube (40) and the inner tube (41) are seamlessly connected through a seal (43), and can move to change the size of the test pipe; the innermost tubes (42) of the two telescopic pipes are seamlessly connected through a seal (43), so that the two telescopic pipes can move to each other; the telescopic rod (44) acts inside the telescopic pipe, controlling the movement of the inner tube (41) and the outer tube (40) to achieve the extension and shortening of the telescopic pipe. In the experiment, the required pipe size condition is input into the computer, the telescopic rod (44) receives the system instruction, judges and selects the pipe of the required size or length, so that the inner tube (41) and the outer tube (40) undergo relative displacement or the two telescopic pipes move to each other, thereby extending or shortening, so as to meet the conditions input into the computer. Based on this, a turbulence drag reduction loop experiment was conducted. The pressure drop of the experimental sample in the expansion joint test pipe of this size can be obtained by computer analysis, thereby judging the turbulence drag reduction effect.

[0037] The working principle and advantages of this invention are as follows: by utilizing a reciprocating piston pump, the shearing of polymer molecules by traditional centrifugal pumps is avoided. An electromagnetic coil winding (20) is installed outside the pump chamber of the magnetically induced anti-shear bidirectional reciprocating pump. Because the polymer molecules can be orderly arranged along the magnetic field direction in turbulent flow, the resistance of the oil during transportation is reduced, thereby achieving a drag reduction effect. This invention provides a magnetically induced anti-polymer shear bidirectional reciprocating pump that is a simple modification of the original vertical single-stage centrifugal pump, highly adaptable, and easy to manufacture. Its anti-shear performance, when applied in pipeline transportation, can significantly improve transportation efficiency.

[0038] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0039] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in the embodiments can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A shear-resistant small-scale annular turbulence drag reduction evaluation device, characterized in that, The device comprises a gas pressure supply system, a turbulent circulation testing system, a polymer drag-reducing agent addition system, a telescopic pipe diameter-changing drag reduction evaluation system, a waste liquid recovery and sampling system, and a data acquisition system. The gas pressure supply system is directly connected to the experimental loop and is used for nitrogen purging and removing residues from the test oil. The turbulent circulation testing system is used for cyclic testing of the turbulent drag-reducing flow of the finished oil. The polymer drag-reducing agent addition system is directly connected to the experimental loop and is used for quantitative injection of the additive. The magnetically induced anti-shear bidirectional reciprocating pump is located in the turbulent circulation testing system and is used to provide pressure to the oil to achieve finished oil circulation. The telescopic pipe diameter-changing drag reduction evaluation system is directly connected to the experimental loop and is used to change the pipe diameter and length. The data acquisition system is located outside the experimental pipe section and is used to monitor and record parameters such as time, pressure, temperature, and flow rate. The waste liquid recovery and sampling system is directly connected to the experimental loop and is used for the recovery and sampling of the test fluid.

2. The shear-resistant small-scale annular turbulence drag reduction evaluation device as described in claim 1, characterized in that, The gas pressure supply system includes a 50 L nitrogen cylinder (1), a pressure reducing valve (2), check valves (3), (26), and (28), pressure sensors (5), (17), (21), and (25), a gate valve (4), a three-way valve (27), and a loop device. The internal pressure of the 50 L nitrogen cylinder (1) is 12.5 MPa, and the outlet is connected by a steel cylinder adapter. The pressure reducing valve (2) and the check valve (3) are connected in parallel, with one end connected to the outlet of the nitrogen cylinder and the other end connected to the gate valve (4). The check valves (26) and (28) are installed before the stainless steel pipe is connected to the loop device. The stainless steel pipe is connected to the loop device by welding. The gas is discharged and the pressure is controlled again by adjusting the three-way valve (27).

3. The shear-resistant small-scale annular turbulence drag reduction evaluation device as described in claim 1, characterized in that, The turbulent circulation test system includes a 100 L storage tank (6), a magnetically induced anti-shear bidirectional reciprocating pump (9) and a matching adjustable speed motor, check valves (8), (10), (26), (28), a temperature sensor (20), a turbine flow meter (16), gate valves (7), (22), (24), pressure sensors (5), (17), (21), (25), a series telescopic pipe (23), and an experimental loop. The telescopic pipe is connected in series to the circulation pipe section at a distance of more than 10 m from the outlet of the magnetically induced anti-shear bidirectional reciprocating pump (9).

4. The shear-resistant small-scale annular turbulence drag reduction evaluation device as described in claim 1, characterized in that, The magnetically induced anti-shear bidirectional reciprocating pump includes a position sensor (31), an electromagnetic coil winding (32), a piston (33), a piston rod (34), a connecting rod (35), a motor spindle (36), a motor (37), an outer cavity (38), and an inner cavity (39). The piston moves in a sinusoidal reciprocating cycle, with the starting points differing by 1 / 2 cycle.

5. The shear-resistant small-scale annular turbulence drag reduction evaluation device as described in claim 1, characterized in that, The telescopic tube diameter reduction and drag reduction evaluation system consists of an outer tube (40), an inner tube (41), an innermost tube (42), a seal (43), and a telescopic rod (44). The outer tube (41) has a diameter of 500 mm, the innermost tube (42) has a diameter of 50 mm, the inner tube (41) and the outer tube (40) can move relative to each other, and the connection is equipped with a seal (43). The telescopic rod (44) is composed of two symmetrical and identical telescopic tubes connected together.

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