CN113358943B - Oil flow electrification measuring device and full-section charge measuring method - Google Patents

Abstract

The invention relates to an oil flow electrification measuring device and a full-section charge measuring method. The oil flow electrification measuring device includes an oil pipe with a circular cross section and an oil flow electrification measuring electrometer on the oil pipe; the oil flow electrification measuring electrometer on the oil pipe It means: form an annular groove on the inner wall of the oil pipe, place a ring electrode in the annular groove, the ring electrode and the oil pipe are concentric and coaxial, and at the same time, set a spherical electrode in the oil pipe that can move up and down along the diameter direction of the oil pipe; apply the above The method of measuring the full-section charge of the device: inject oil into the oil pipe and circulate it. At this time, the oil will be charged due to relative flow friction, so that the spherical electrode moves from the inner wall of the oil pipe to the central axis of the oil pipe along the diameter direction. Movement; the spherical electrode monitors the amount of charge at any position above and below the radius of the internal section of the oil pipe; while the ring electrode monitors the amount of induced charge on the pipe wall. The invention can ingeniously realize the full-section electric charge measurement of the charged oil flow in the pipe.

Description

A device for measuring oil flow charging and a method for measuring full-section charge

technical field

The invention belongs to the technical field of oil flow electrification measurement, and relates to an oil flow electrification measurement device and a full-section charge measurement method, in particular to a device for directly measuring the charge of flowing oil in a pipeline and a full-section charge measurement method.

Background technique

The electrification of the oil flow is mainly due to the charge separation phenomenon caused by the liquid flowing through the surface of the solid material. When the insulating lubricant is in contact with the pipe wall, due to the adsorption of the active molecules (positive and negative ions) in the lubricant with the pipe wall, when the lubricant The flow causes the charges at the liquid-solid interface to separate, causing movement processes such as charge migration, accumulation and disappearance, and finally reaches equilibrium, forming oil flow electrification. It is easy to obtain the electric charge of oil flow in the pipeline, but its current density distribution is often unclear.

Therefore, the present invention designs a set of test equipment for measuring the current distribution during laminar flow and turbulent flow in the pipeline. Assuming that the lubricant flow in the pipeline is symmetrically distributed, and the electrification of the oil flow has a static property, various points can be obtained through the measurement points of the pipeline cross-section change. The current value and thus obtain the current distribution of the pipe section, including the charge amount of the pipe wall. And according to the radial distribution characteristics of the flow velocity, the charge density distribution of the pipeline lubricant body is determined.

Contents of the invention

In order to solve the problems existing in the prior art, the present invention provides an oil flow electrification measurement device and a full-section charge measurement method; the technical problem solved by the present invention is to design an oil flow electrification measurement device for the current pipeline oil flow electrification measurement It can only measure the electrification of the oil flow within a certain distance from the pipe wall. Actually, when the oil flows in the pipe, due to relative motion, the electrification of the oil at various points inside the pipe section that is in contact with the pipe wall and the charge distribution on the pipe wall It needs to be known, so an ingenious structure is designed to realize the full-section charge measurement of the charged oil flow in the pipe and pipe wall.

In order to achieve the above object, the scheme adopted by the present invention is as follows:

An oil flow electrification measuring device, comprising an oil pipe with a circular cross section and an oil flow electrification measuring electrometer on the oil pipe;

The electrometer for oil flow charging measurement on the oil pipe refers to: an annular groove is formed on the inner wall of the oil pipe, and a ring electrode is placed in the annular groove. The ring electrode and the oil pipe are concentric and coaxial. The direction of the spherical electrode moves up and down. In this way, the charge distribution at any position above and below the radius of the internal section of the pipeline can be measured, and the charge distribution on the pipe wall can also be monitored, so as to realize all-round monitoring of the charged measurement of the pipeline oil flow.

As a preferred technical solution:

In the above-mentioned oil flow charged measurement device, the spherical electrode is located on one side of the plane where the ring electrode is located and is installed on the oil pipe at the same time, and a certain transverse distance is left between the ring electrode and the spherical electrode, in order to prevent two The measurement data disorder caused by mutual electromagnetic induction phenomenon during the measurement process. The two are a complementary relationship, that is, the spherical electrode can only measure the charge of the oil inside the oil pipe, and the ring electrode can only measure the charge on the wall of the oil pipe, both of which can not be measured by the other part The position of the charge, so there is a complementary relationship and the charge data of all positions of the tubing are measured.

In the aforementioned oil flow electrification measuring device, the ring electrode is placed in the ring groove and sealed with an insulating sleeve (to prevent the leakage of the pipe wall from affecting the measurement data); and the ring electrode is connected to one end of the wire II.

As mentioned above, a kind of oil flow electrification measuring device is provided with a spherical electrode capable of moving up and down along the diameter direction of the oil pipe in the oil pipe. The ring is fixed on the surface of the oil pipe, and a straight copper tube with an outer diameter of 2mm is placed in the round hole. The copper tube is driven by the driving mechanism and can move up and down. The end of the copper tube is equipped with a spherical electrode, and the spherical electrode and the wire One end of I is connected; the protective cover is assembled on the sealing ring to compress the sealing ring. The sealing ring is to prevent oil leakage, and the protective cover is to ensure that the wire I and the spherical electrode move up and down in a straight line under the action of the servo motor, preventing its trajectory from deviating from the expected set up and down straight line movement, and at the same time reinforcing the sealing ring to prevent it from falling.

The copper tube can not only be used as a source electrode stabilizer (to prevent the electrode from being subject to a large bending moment when the pipeline flow rate is high), but also has the function of shielding the measurement signal from interference.

According to the aforementioned oil flow electrification measuring device, the drive mechanism includes a servo motor connected to a copper tube through an aluminum alloy tube. The servo motor can be used for both step measurement and continuous measurement to complete the precise positioning of the spherical electrode.

A kind of oil flow electrification measuring device as mentioned above, wire I is the wire that PTFE wraps (this wire is the steel annealed wire that diameter is 600 μ m, and the thickness of PTFE wrap is 75 μ m), adopts PTFE to wrap wire and cable simultaneously because Its material has excellent electrical insulation, chemical stability, and unique properties of temperature resistance and wide frequency range, which can be reasonably and effectively applied in the case of oil flow live monitoring.

As mentioned above, the oil flow electrification measurement device, the spherical electrode is a gold-plated ball probe with a diameter of 2 mm, which is ingenious and simple in design compared with the existing electrode probe structure, and at the same time it is easier to collect oil flow electrification signals.

As mentioned above, the other ends of the lead wire I and the lead wire II are connected to the signal conditioning circuit board. The signal conditioning circuit board converts and amplifies the signal and inputs it to an external signal acquisition card. The signal acquisition card is connected to the computer. (for real-time storage and display of electrical signals).

The above-mentioned oil flow electrification measuring device further includes a scale for measuring the position of the spherical electrode with a resolution of micron; the scale is connected to the aluminum alloy tube. When the aluminum alloy tube drives the spherical electrode to move, the scale is also monitoring the position data of the spherical electrode in real time; when the spherical electrode moves to the designated measurement position with the aid of the position data of the scale, the spherical electrode starts to measure the amount of oil charge. The data is collected and finally transmitted to the computer through the wire I, so as to achieve the purpose of measuring the electrification of the oil flow at any position up and down the internal section radius of the oil pipe.

The above-mentioned oil flow electrification measuring device further includes a sliding guide rail fixedly connected with the aluminum alloy tube, used for stabilizing the movement of the aluminum alloy tube and its connection structure.

An oil flow electrified measurement device as described above, further comprising an oil tank connected to the oil pipe, filter I and filter II for filtering oil impurities in the oil pipe, a flow pump for regulating the flow of oil in the oil pipe, and a flow pump for measuring oil flow in the oil pipe. An oil pressure gauge for oil pressure, an adjustable throttle valve for controlling the flow of oil in the oil line, and a flow meter for testing the flow of oil in the oil line.

The present invention also provides a method for measuring the full-section charge by using an oil flow electrification measuring device as described in any one of the above items. Oil is injected into the oil pipe and circulated. At this time, the oil will be charged due to relative flow friction. The spherical electrode is moved from the inner wall of the oil pipe to the central axis of the oil pipe along the diameter direction; the spherical electrode is used to monitor the charge at any position on the upper and lower radii of the inner section of the oil pipe; and the ring electrode monitors the induced charge on the pipe wall.

As a preferred technical solution:

According to the method mentioned above, the servo motor used in the electrometer for electrification measurement of oil flow can not only control the position of the spherical electrode by jogging, but also control the position of the spherical electrode continuously, that is, the movement of the spherical electrode is jogging or continuous movement.

Beneficial effect

(1) A kind of oil flow electrification measuring device of the present invention adopts a servo motor, and the aluminum alloy tube driven by the servo motor to connect the spherical electrode and the scale can complete the inching operation of the probe, and can also continuously run steplessly. Precise positioning in the oil;

(2) Compared with the original measuring electrode (which can only measure the internal charge of the tube), a kind of oil flow charged measuring device of the present invention has a simple and ingenious structure. The copper tube adopts the form of a straight tube and Install a spherical electrode on the end, and the copper tube with the ball electrode can reach any position up and down the inner radius of the pipeline, and can simultaneously complete the charge measurement inside the flowing oil;

(3) A kind of oil flow electrification measuring device of the present invention adopts PTFE to wrap wire and adopts copper tube to be nested in the outside, not only can be used as source electrode stabilizer (under large flow rate, electrode can be subjected to the effect of bending force); Another function is to shield the measurement signal; at the same time, this structure places the measurement electrodes to complete the positioning of the measurement electrodes;

(4) A kind of measuring method of full cross-section electric charge of the present invention adopts the annular electrode of the same diameter as pipe wall, is fixedly installed on pipe wall and is wrapped by insulating sleeve, can monitor the electric charge distribution on pipe wall in real time, solves the problem of spherical electrode The problem that the charge distribution on the tube wall cannot be monitored. This oil flow charging measurement device collects the charge data through the spherical electrode and the ring electrode, and converts the charge data into a voltage signal through the signal conditioning module and transmits it to the computer, and then converts the voltage signal into a charge density through a signal processing method, and finally obtains The charge distribution at each point in the full section of the pipeline.

Description of drawings

Fig. 1 is the overall structure schematic diagram of the oil flow electrification measuring device of the present invention;

Fig. 2 is the structural representation of the oil flow electrification measuring electrometer of the present invention;

Fig. 3 is the schematic diagram of the installation structure of spherical electrode and annular electrode of the present invention;

Fig. 4 is a schematic diagram of the positional relationship between the ring electrode and the oil pipe of the present invention;

Fig. 5 is the structural representation of drive mechanism of the present invention;

Fig. 6 is the schematic diagram 1 of ring electrode test of the present invention;

Fig. 7 is the schematic diagram 2 of ring electrode test of the present invention;

Among them, 1-oil tank Ⅰ, 2-filter Ⅰ, 3-flow pump, 4-oil pressure gauge, 5-adjustable throttle valve, 6-oil flow live measurement electrometer, 7-flow meter, 8-filter Ⅱ , 9-oil pipe, 10-scale, 11-servo motor, 12-signal conditioning circuit board, 13-acquisition card, 14-computer, 15-pipe wall, 16-sealing ring, 17-protective cover, 18-copper Tube, 19-wire I, 20-wire II, 21-insulating sleeve, 22-ring electrode, 23-spherical electrode, 24-aluminum alloy tube, 25-sliding guide rail.

Detailed ways

The present invention will be further described below in combination with specific embodiments. It should be understood that these examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the teachings of the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of the present application.

An oil flow electrification measuring device, as shown in Figures 1 to 5, includes an oil pipe 9 with a circular cross section, an oil tank I1 connected to both ends of the oil pipe 9, and oil pipes 9 sequentially arranged to filter oil impurities in the oil pipe 9 Filter Ⅰ2, flow pump for regulating oil flow in oil pipe 9, oil pressure gauge for measuring oil pressure in oil pipe 9, adjustable throttling valve for controlling oil flow in oil pipe 9, electrometer for oil flow electrification measurement 6. A flowmeter 7 for testing oil flow in the oil pipe 9, a filter II 8 for filtering oil impurities in the oil pipe 9, a scale 10 and a sliding guide rail 25 for measuring the position of the spherical electrode 23 with a resolution of micron level,

The oil flow charging measurement electrometer 6 on the oil pipe 9 refers to: an annular groove is formed on the inner wall 15 of the oil pipe 9, and an annular electrode 22 is placed in the annular groove, and the annular electrode 22 is concentric and coaxial with the oil pipe 9. At the same time, the A hole is arranged on the side wall of the oil pipe 9, and a sealing ring 16 with a round hole reserved in the middle is placed in the hole and is fixedly installed on the surface of the oil pipe. A straight pipe structure with an outer diameter of 2 mm is placed in the round hole 18, and the red copper pipe 18 is driven by the driving mechanism and can move up and down. The end of the copper tube 18 is equipped with a spherical electrode 23. The spherical electrode 23 is a gold-plated ball probe with a diameter of 2mm. The spherical electrode 23 is wrapped with PTFE. Steel annealed wire, the thickness of PTFE wrapping is 75 μ m) one end is connected; Assembly protective cover 17 is pressed on sealing ring 16; Prevent the leakage of the pipe wall 15 from affecting the measurement data); and the ring electrode 22 is connected to one end of the wire II 20;

The spherical electrode 23 is positioned at one side of the ring electrode 22 and is installed on the oil pipe 9 at the same time, and there is a certain lateral distance between the ring electrode 22 and the spherical electrode 23 (the central axis distance of the spherical electrode and the central axis distance of the ring electrode are 15 ~ 20mm);

The drive mechanism includes a servo motor 11 connected to the copper tube 18 through the aluminum alloy tube 24; the servo motor 11 can measure step by step or continuously to complete the precise positioning of the spherical electrode; the scale 10 is connected to the aluminum alloy tube 24 ; The sliding guide rail 25 is fixedly connected with the aluminum alloy tube 24, and is used to stabilize the movement of the aluminum alloy tube 24 and its connection structure;

The other end of lead I19 and lead II 20 all inserts signal conditioning circuit board 12, and signal conditioning circuit board 12 inputs external signal acquisition card 13 after signal conversion amplifies, and signal acquisition card 13 is connected with computer 14;

Using the above-mentioned oil flow electrification measuring device to carry out the measurement method of the full-section charge, the specific process is as follows:

Inject the oil into the oil tank Ⅰ1, turn on the flow pump 3, the oil circulates in the oil pipe 9, and control and measure the flow rate, flow velocity and oil pressure through the adjustable throttle valve 5, oil pressure gauge 4 and flow meter 7, so that the oil flows in the oil pipe 9 internal circulation, at this time the oil will be charged due to flowing friction, turn on the servo motor 11 of the oil flow electrification measurement electrometer 6, the servo motor 11 drives the copper tube 18 to move up and down through the aluminum alloy tube 24, and the inside of the copper tube 18 The wire I19 wrapped in PTFE drives the spherical electrode 23 to move up and down from the inner wall of the oil pipe 9 along the diameter direction to the central axis of the oil pipe 9, and at the same time the scale 10 completes the positioning of the spherical electrode 23; the movement of the spherical electrode 23 is a point move or move continuously; the spherical electrode 23 reaches any position up and down the inner radius of the pipeline to detect the charge of the oil in the pipeline, and the ring electrode 22 can monitor the induced charge on the pipe wall 15. The spherical electrode 23 and the ring electrode 22 The collected charge signal is collected by the acquisition card 13 through the signal conditioning circuit board 12, and finally displayed on the computer 14 in real time to complete the online measurement.

Wherein, the method for the spherical electrode 23 to monitor the electric charge at any position above and below the internal section radius of the oil pipe 9 is as follows: the oil flow in the pipe is approximately turbulent, and the charge density is regarded as uniform. Since the inner diameter of the pipeline is much smaller than the length of the pipeline, the oil in the pipeline can be approximated as an infinitely long charged cylinder. Assuming the charge density of the oil is ρ, the potential at any radius on the internal cross section of the oil pipe 9 satisfies:

则V_r＝ρβ；由管内横截面上各点电位V_r与ρ有如下关系：In the formula: r _o is the radius of the pipeline; r is the distance between the center of the spherical electrode measuring point and the axis of the pipeline; ε is the dielectric constant of the oil, and ε = ε _o ε _r , where ε _o is the vacuum dielectric constant of the oil, ε _r is the relative permittivity of the oil; ρ is the charge density at different points above and below any radius on the cross section of the tube. make

Then V _r = ρβ; the potential V _r of each point on the cross section of the tube has the following relationship with ρ:

Then, the amount of charge sensed and measured above and below any radius of the spherical electrode 23 is obtained by calculating the formula of Q _s =Sρ. Wherein, S is the effective sensing area of the spherical electrode 23;

The method for the ring electrode 22 to monitor the amount of induced charge on the tube wall 15 is: approximately consider that the electrostatic field distribution formed on the ring electrode 22 is a free electrostatic field of infinite space, its ring electrostatic sensor mathematical model and the OXY plane (located on the ring electrode The oil pipe cross-section at the central axis position, where the plane is the OXY plane, and the center of the cross-section is point O) as shown in Figure 6 and Figure 7: the coordinates of the position P of the charged metal abrasive grains are (x, 0, z ), the coordinates of point M are (x, 0, H/2), H is the width of the ring electrode, point G, point N and point M are coplanar in the coordinate system OXYZ, and the projections of points M and N on the plane XOY plane They are M`, N`, |MN|=|M`N`|, according to Gauss’s law and Coulomb’s law, the induced charge generated by the interaction between the oil flow and the pipe wall 15 is obtained, and the calculation and analysis formula of the ring electrostatic sensor for:

In the formula: ignoring the size of the charged abrasive grains, Q _a is the amount of induced charge generated by the charged abrasive grains on the ring electrode; R is the inner diameter of the ring electrode; q is the amount of induced charge on the ring electrode at P; x is the charge The X coordinate value of the position of the electric abrasive grain; the angle φ is the angle between ON` and OM`; z is the Z coordinate value of the position of the charged abrasive grain.

Claims (8)

1. An oil flow electrification measuring device is characterized in that: comprises an oil pipe (9) with a circular cross section and an oil flow electrification measurement electrometer (6) on the oil pipe (9); the oil flow electrification measurement electrometer on the oil pipe (9) is as follows: an annular groove is formed on the inner side wall (15) of the oil pipe (9), an annular electrode (22) is placed in the annular groove, the annular electrode (22) and the oil pipe (9) are concentric and coaxial, and meanwhile, a spherical electrode (23) capable of moving up and down along the diameter direction of the oil pipe (9) is arranged in the oil pipe (9); the spherical electrode (23) is connected with one end of a lead I (19), the annular electrode (22) is connected with one end of a lead II (20), the other ends of the lead I (19) and the lead II (20) are connected with a signal conditioning circuit board (12), the signal conditioning circuit board (12) converts and amplifies signals and then inputs the signals into an external signal acquisition card (13), and the signal acquisition card (13) is connected with a computer (14); the spherical electrode (23) is positioned on one side of the annular electrode (22), and a certain transverse distance is reserved between the annular electrode (22) and the spherical electrode (23) to prevent the annular electrode and the spherical electrode from generating mutual electromagnetic induction phenomenon in the measurement process to cause measurement data disorder.

2. An oil flow electrification measuring device in accordance with claim 1, wherein the annular groove is sealed with an insulating sleeve (21) after the annular electrode (22) is disposed in the annular groove.

3. The oil flow electrification measuring device according to claim 2, wherein the spherical electrode (23) provided in the oil pipe (9) so as to be movable up and down in a diameter direction of the oil pipe (9) means: a hole is arranged on the side wall of the oil pipe (9), a sealing ring (16) with a circular hole reserved in the middle is placed in the hole and fixedly mounted on the surface of the oil pipe, a red copper pipe (18) with a straight pipe structure is placed in the circular hole, the red copper pipe (18) is driven by a driving mechanism and can move up and down, and a spherical electrode (23) is mounted at the tail end of the red copper pipe (18); a protective cover (17) is assembled on the sealing ring (16) to press the sealing ring (16).

4. The oil flow electrification measuring device according to claim 3, wherein the driving mechanism includes a servo motor (11) connected to the copper tube through an aluminum alloy tube (24); the lead I (19) connected with the spherical electrode (23) is a PTFE-coated lead, and the motion form of the lead is inching or continuous movement.

5. The oil flow electrification measuring device according to claim 4, further comprising a scale (10) for measuring the position of the ball electrode (23) with a resolution of the order of micrometers; the scale (10) is connected with an aluminum alloy tube (24).

6. The oil flow electrification measuring device according to claim 4, further comprising a sliding guide (25) fixedly connected with the aluminum alloy tube (24) for stabilizing the movement of the aluminum alloy tube (24) and the structure connected thereto.

7. The live oil flow measuring device according to claim 1, further comprising an oil tank (1) communicating with the oil pipe (9), a filter i (2) and a filter II (8) for filtering oil impurities in the oil pipe (9), a flow pump (3) for adjusting the oil flow in the oil pipe (9), an oil pressure gauge (4) for measuring the oil pressure in the oil pipe (9), an adjustable throttle valve (5) for controlling the oil flow in the oil pipe (9), and a flow meter (7) for testing the oil flow in the oil pipe (9).

8. The method for measuring the charge of the whole section by using the oil flow electrification measuring device as set forth in any one of claims 1 to 7, characterized in that: injecting oil into the oil pipe (9) and making the oil circularly flow, wherein the oil liquid generates charge due to relative flow friction at the moment, so that the spherical electrode (23) moves from the inner wall of the oil pipe (9) to the central shaft of the oil pipe (9) along the diameter direction; the spherical electrode (23) monitors the charge quantity of the upper and lower arbitrary positions of the radius of the internal section of the oil pipe (9); and a ring electrode (22) monitors the amount of induced charge on the wall.

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