CN115247984A - Electrode structure capable of focusing shock wave energy and electrode device composed of same - Google Patents
Electrode structure capable of focusing shock wave energy and electrode device composed of same Download PDFInfo
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- CN115247984A CN115247984A CN202210832819.9A CN202210832819A CN115247984A CN 115247984 A CN115247984 A CN 115247984A CN 202210832819 A CN202210832819 A CN 202210832819A CN 115247984 A CN115247984 A CN 115247984A
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- 230000035939 shock Effects 0.000 title claims abstract description 33
- -1 polypropylene Polymers 0.000 claims abstract description 47
- 239000004743 Polypropylene Substances 0.000 claims abstract description 44
- 229920001155 polypropylene Polymers 0.000 claims abstract description 44
- 230000000694 effects Effects 0.000 claims abstract description 22
- 239000011435 rock Substances 0.000 claims abstract description 22
- 239000007788 liquid Substances 0.000 claims abstract description 18
- 239000003990 capacitor Substances 0.000 claims abstract description 12
- 238000004146 energy storage Methods 0.000 claims abstract description 11
- 239000010438 granite Substances 0.000 claims description 25
- 238000007789 sealing Methods 0.000 claims description 19
- 239000011148 porous material Substances 0.000 claims description 10
- 238000000034 method Methods 0.000 claims description 9
- 238000005553 drilling Methods 0.000 claims description 7
- 239000000463 material Substances 0.000 claims description 7
- 239000008399 tap water Substances 0.000 claims description 7
- 235000020679 tap water Nutrition 0.000 claims description 7
- 238000005336 cracking Methods 0.000 claims description 5
- 238000012360 testing method Methods 0.000 claims description 5
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 claims description 4
- 238000007599 discharging Methods 0.000 claims description 3
- 239000000243 solution Substances 0.000 claims 8
- 239000012266 salt solution Substances 0.000 claims 1
- 239000003245 coal Substances 0.000 description 10
- 238000005516 engineering process Methods 0.000 description 10
- 238000005065 mining Methods 0.000 description 7
- 238000005422 blasting Methods 0.000 description 5
- 238000012544 monitoring process Methods 0.000 description 3
- 238000011160 research Methods 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- 230000002265 prevention Effects 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000000428 dust Substances 0.000 description 1
- 238000004880 explosion Methods 0.000 description 1
- 239000002360 explosive Substances 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 230000000149 penetrating effect Effects 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 230000010349 pulsation Effects 0.000 description 1
- 230000003578 releasing effect Effects 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F42—AMMUNITION; BLASTING
- F42D—BLASTING
- F42D1/00—Blasting methods or apparatus, e.g. loading or tamping
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F42—AMMUNITION; BLASTING
- F42D—BLASTING
- F42D3/00—Particular applications of blasting techniques
Abstract
The invention discloses an electrode structure capable of focusing shock wave energy under a liquid electric effect and an electrode device formed by the electrode structure. The electrode structure comprises a high-voltage electrode, a grounding electrode, a polypropylene insulating sleeve, a rubber gasket, a fixing nut and an electrode shell; the electrode device comprises a charging power supply, an energy storage capacitor, a current-limiting protection resistor, a power switch, a high-voltage electric pulse switch, a gas gap switch, a super-dynamic strain gauge and an electrode structure. Under the action of the hydro-electric effect, the invention focuses the energy of the generated shock wave during the discharge of the hydro-electric effect through the area size and distribution of the prefabricated hole gaps of the electrode shell, realizes the directionality of the released energy, and has certain applicability in the fields of directional rock crushing and the like.
Description
Technical Field
The invention relates to an electrode structure capable of focusing shock wave energy under a liquid electric effect and an electrode device composed of the electrode structure, belongs to a high-voltage electric pulse technology, and can be applied to the fields of high-voltage electric pulse rock breaking, gas extraction and the like.
Background
In the coal mining process, rock stratum control is an important link for safe and efficient production of coal mines. With the continuous increase of the mining depth, the geological conditions are gradually worsened, and the probability of causing mine safety accidents is also continuously increased. During mining, coal rock mass under high stress is extremely prone to accumulate huge energy, and in a specific situation, the energy release is accompanied by the generation of impact mine pressure. The generation of the impact mine pressure can cause the coal rock mass to be instantaneously damaged, cause the damage of a roadway system and even endanger the personal safety.
The prevention and control of the impact mine pressure is the most important link in the coal mining process, and has serious influence on the safety and the high efficiency of coal mining. The existing mature stress regulation and control technologies comprise a drilling blasting technology and a hydraulic fracturing technology, and the hydraulic fracturing has low rock breaking efficiency due to the fact that the equipment size is large, the flow of required water is large, hole sealing is difficult under the high-pressure condition and the like; the drilling blasting technology needs to use chemical explosives, and has certain risks under the condition of being rich in gas in a coal mine, and the direction of the broken rocks of blasting is uncontrollable and can generate a large amount of dust, so that the drilling blasting has certain limitations.
At present, a new technology, namely high-voltage electric pulse, is researched by broad scholars to be applied to the field of rock breaking, and has certain prospect in the field of coal mining and scour prevention. The technology of fracturing the hard top plate by adopting high-voltage electric pulse is safer, the coal mine gas explosion problem caused by blasting can be effectively avoided, the high pressure problem of fracturing rocks by hydraulic fracturing is also avoided, and the hard top plate can be effectively weakened under less water flow.
The underwater high-voltage electric pulse technology is characterized in that high-voltage electric equipment is charged through a capacitor bank and then is released in a very short time through an underwater electrode, pulse discharge is generated in water, and a formed plasma channel penetrates through two electrodes of the electrode and continuously expands to form shock waves. Some shock waves are generated by the pulsation of the bubbles accompanying the generation and collapse of the bubbles under the action of high temperature and high pressure during the discharge process, but the generation of the shock waves is based on the formation of plasma channels, the shock waves are diffused outward in a shape similar to a sphere between the two electrode gaps, and the energy release has no specific direction and is relatively dispersed.
For the problem of stress concentration caused by the underground hard top plate, not only a stress is weakened by a cracking means, but also the directional cracking is required under different conditions, so that an efficient stress regulation and control technology can be formed. Therefore, the energy generated by electrode discharge is focused, thereby realizing the maximization of energy release and the controllability of the release direction, and having good application prospect on underground stress regulation and control.
Disclosure of Invention
The invention aims to provide an electrode structure capable of focusing shock wave energy under the liquid electric effect and an electrode device formed by the electrode structure, and researches the change relation between the shock wave released by high-voltage electric pulse and the electrode structure.
The invention provides an electrode structure capable of focusing shock wave energy under a liquid electric effect, which comprises a high-voltage electrode, a grounding electrode, a polypropylene insulating lantern ring, a rubber gasket, an electrode shell, a fixing nut and a fixing ring, wherein the high-voltage electrode is arranged on the high-voltage electrode;
the upper end of the high-voltage electrode is provided with threads, the middle part of the high-voltage electrode is connected and fixed with a polypropylene insulating lantern ring through a fixing nut, the high-voltage electrode is positioned in the polypropylene insulating lantern ring, the polypropylene insulating lantern ring is fixed on the upper part of the electrode shell, and the polypropylene insulating lantern ring is fixedly connected with the electrode shell through a fixing circular ring; a rubber gasket is sleeved at the contact part of the polypropylene insulating lantern ring and the electrode shell; the contact tightness of the two is increased;
the grounding electrode is fixed at the lower end of the electrode shell through threads; the grounding electrode is screwed in through the thread at the bottom of the electrode shell and then is fixed by using a nut;
the high-voltage electrode and the grounding electrode are oppositely arranged in the hollow hole of the electrode shell, the distance between the grounding electrode and the high-voltage electrode is adjustable by rotating the lower end thread of the grounding electrode, and the distance between the two electrodes is set to be 1mm-5mm.
The total length of the high-voltage electrode is 74mm, the high-voltage electrode consists of an upper end, a middle end and a lower end, the upper end is a cylinder with the diameter of 4mm and the length of 70mm, and M8-sized threads with the length of 25mm are lathed at the top of the cylinder, namely the upper end of the high-voltage electrode threads; the middle end is a cylinder with the diameter of 5mm and the length of 2mm, and the chamfer angle with the length of 1mm at the lower part is 30 degrees; the lower end is a cylinder with the diameter of 2mm and the length of 2mm, and the bottom is chamfered to be a tip end of 45 degrees.
The grounding electrode consists of a smooth cylinder and a threaded cylinder; the diameter of the smooth cylinder of the upper half part is 2mm, the length is 3mm, and the top chamfer angle is a tip of 45 degrees; the lower half part is a threaded cylinder of M8, and the length is 17mm.
The polypropylene insulating lantern ring is a cylinder with the diameter of 8mm and the length of 95 mm; the diameter of the built-in cavity is 4mm; at a distance of 35mm from the upper top, a polypropylene ring of 12mm diameter and 4mm length was added, which served to secure it to the electrode casing.
The electrode shell is cylindrical in appearance, hollow in interior, and an electrode penetrates through the electrode shell, the electrode shell is composed of three sections of cylinders with different outer diameters, a first section of cylinder at the upper part is connected with the fixed ring, a rubber gasket is arranged in a second section of cylinder at the middle part, and the outer side of a third section of cylinder at the lower part is of a smooth structure; the first section of cylinder of the electrode shell is provided with external threads for connecting a fixed ring; the center of the top of the first section of the cylinder is provided with a step hole, and the upper hole of the step hole is connected with a polypropylene insulating lantern ring; the bottom in the second section of cylinder is provided with a hole for placing a rubber gasket; the center of the bottom of the third section of cylinder is provided with internal threads for fixing the grounding electrode, and the cylindrical surface above the third section of cylinder is provided with an electrode shell empty hole for exposing the electrode.
One or more of the electrode shell holes 20 are arranged, the cross section of each electrode shell hole is rectangular, and the sizes of the electrode shell holes are 2mm multiplied by 10mm, 3mm multiplied by 10mm or 5mm multiplied by 10mm (which refers to the cross section size corresponding to the front view of the drilled hole); only one hollow hole can be drilled at the bottom of the third section of the cylinder of the electrode shell, and two hollow holes (correspondingly arranged in the front and the back of the electrode) or three hollow holes (three hollow holes are drilled along the direction line of 120 degrees) can also be drilled. The controllable direction of the shock wave and the energy focusing of the electrode structure are realized through the hollow hole arranged at the lower end of the electrode shell.
The diameter of the fixed ring is 22mm, the length of the fixed ring is 13mm, threads with the length of 11mm and the diameter of M13 are arranged in the fixed ring, and a round hole with the diameter of 8mm is drilled at the top of the fixed ring and used for penetrating through the polypropylene insulating lantern ring.
The high-voltage electrode penetrates through the built-in cavity from the lower part of the polypropylene insulating lantern ring, and the high-voltage electrode and the polypropylene insulating lantern ring are fixed by a nut; then placing the polypropylene insulating lantern ring in the built-in cavity of the electrode shell; fixing the polypropylene insulating lantern ring and the electrode shell by using a fixing ring; the grounding electrode is screwed in through the threads at the bottom of the electrode shell and then is fixed by using a nut. When the electrode structure is fixed, the distance between the screwed grounding electrode and the high-voltage electrode can be adjusted to realize the adjustment of the electrode distance, and the distance between the two electrodes can be 1mm-5mm for testing.
The shock wave generated by the connection of the two electrodes is the key for breaking rocks, the discharge channel is determined by the distance between the two electrodes, and the released pulse energy can be realized by changing the distance between the two electrodes during research, so that monitoring and analysis are carried out, and the optimal electrode spacing is obtained.
The invention also provides an electrode device which is made by adopting the electrode structure and can focus shock wave energy under the hydro-electric effect, and the electrode device comprises a charging power supply, an energy storage capacitor, a current-limiting protection resistor, a power switch, a high-voltage electric pulse switch, a gas gap switch, a super-dynamic strain gauge and an electrode structure; the electrode structure is placed in the rock cavity, and the high-voltage cable connects the charging power supply, the energy storage capacitor, the current-limiting protection resistor, the power switch, the high-voltage electric pulse switch, the gas gap switch, the ultra-dynamic strain gauge and the electrode structure in sequence.
The monitoring object of the electrode device can select granite samples of 100mm multiplied by 100mm, 150mm multiplied by 150mm and 300mm multiplied by 300mm, one surface of the granite sample is selected, and a cylindrical cavity with the diameter of 12mm and the length of 75mm is drilled at the center of the granite sample and used for injecting a conductive solution and placing an electrode structure. In order to make the electrode structure closely contact with the cavity, a sealing gasket is arranged at the bottom of the electrode circular ring and used for achieving the effect of sealing the electrode and the rock material cavity.
The conductive liquid is injected into the granite cavity, and different types of solutions can be used, such as tap water, naCl solutions with different concentrations, caCl with different concentrations 2 Solution, alCl of different concentrations 3 Solutions, etc.; the concentration of the three conductive liquids can be tested by adopting five gradients of 1mol/L, 1.5mol/L, 2mol/L, 3mol/L and 5 mol/L; the aspects of green safety, wide sources, cost performance and the like are considered when the conductive liquid is selected, tap water is selected as the conductive liquid, and the tap water has the most practicability in the actual application environment. During research, different conductive liquids can be considered to be replaced, and the pulse energy generated by the different conductive liquids in the discharging process is monitored, so that the optimal conductive liquid for breaking rocks is analyzed, and the damage effect is more favorable.
The method comprises the steps of adhering strain gauges to two sides of a granite sample, selecting two models of BFH120-80AA-D150 and BFH120-20AA-D150, adhering two BFH120-20AA-D150 strain gauges to one side in the same direction with an electrode shell pore, selecting the position of the strain gauges to be one-on-one, adhering one BFH120-80AA-D150 strain gauge to a symmetrical plane, selecting the position of the center, adhering one BFH120-20AA-D150 strain gauge to the rock wall surface perpendicular to the electrode shell pore direction, and adhering the position of the strain gauge to the upper position in the same model.
And a super-dynamic strain gauge is connected with the strain gauge to acquire the frequency during high-voltage pulse discharge. When the two electrodes are conducted in the sealed cavity, shock waves generated by the conduction of the two electrodes can be collected and analyzed through the ultra-dynamic strain gauge, and the correlation between the size and the direction of the electrode shell cavity and the pulse propagation direction and frequency under the condition of conducting liquid is researched, so that the relationship between the size and the direction of the electrode cavity and the shock wave energy release and propagation direction is explored.
The invention provides application of an electrode device capable of focusing shock wave energy under the liquid-electric effect, which comprises the following steps:
a. the test material can select granite samples of 100mm multiplied by 100mm, 150mm multiplied by 150mm and 300mm multiplied by 300mm, a cylindrical cavity hollow hole is drilled at the center of one surface, and the diameter and the length of an electrode are selected according to the size of the hollow hole.
b. Randomly selecting the axis position of one side surface, and sticking two strain gauges, wherein the sticking positions are selected from one upper part and one lower part; a strain gauge is pasted on the other opposite side surface, and the pasting position is selected to be horizontal to the electrode gap; and a strain gauge is adhered to the other adjacent side surface, and the position of the strain gauge is horizontal to the electrode gap.
c. The high-voltage electrode is placed in a cavity of the polypropylene insulating lantern ring, and the upper end of the high-voltage electrode is fixed by a nut; placing a polypropylene insulating lantern ring in the electrode cavity; in order to ensure good sealing performance, a rubber gasket is sleeved at the contact part of the ring of the insulating lantern ring and the electrode shell and then is connected and fixed by a fixing ring; the grounding electrode is screwed into the bottom of the electrode shell through threads, the distance between the high-voltage electrode and the grounding electrode is adjusted, the electrode distance can be between 1mm and 5mm, and the grounding electrode is fixed by a fixing nut after the gap distance is adjusted.
d. The size of the empty hole of the electrode shell can be 2mm multiplied by 10mm, 4mm multiplied by 10mm, 5mm multiplied by 10mm and other specifications, and one empty hole, two empty holes, three empty holes and other conditions can be selected to form different electrode structures.
e. The conductive solution is injected into the granite drilled cavity, and different types of solutions can be used, such as tap water, naCl solution with different concentrations, caCl with different concentrations 2 Solution, alCl of different concentrations 3 Solutions, etc.; the concentration of the three conductive liquids can be tested by adopting five gradients of 1mol/L, 1.5mol/L, 2mol/L, 3mol/L and 5 mol/L. In order to enhance the sealing effect, a sealing gasket is arranged at the bottom of the circular ring of the electrode shellAnd the tightness degree of the electrode and the granite cavity is improved by using the sealing washer.
f. The electrode and the granite sample are assembled and fixed by utilizing the upper cover plate and the lower cover plate, and the tightness of the sample, the electrode and the cover plate is fixed by rotating nuts at four top corners of the upper cover plate and the lower cover plate. The upper end of the high-voltage electrode is connected with a high-voltage cable, and the upper cover plate and the fixed ring of the electrode are connected with a grounding cable.
g. And connecting the fixed electrode and the sample to a high-voltage pulse discharge device, and respectively connecting the adhered strain gauges to an acquisition port of the ultra-dynamic strain gauge.
h. The charging power supply, the energy storage capacitor, the current-limiting protection resistor, the power switch, the high-voltage electric pulse switch, the gas gap switch, the ultra-dynamic strain gauge and the electrode structure are sequentially connected through the high-voltage cable, the ultra-dynamic strain gauge is started firstly, then the power switch is turned on, the voltage value of the charging power supply is observed, the charging voltage can be selected according to actual conditions and can be within the range of 5kV-20kV preliminarily, and after the voltage value is reached, the power switch is turned off, and the high-voltage pulse switch is turned on to discharge. And after the discharge is finished, the ultra-dynamic strain gauge stops collecting data, leaks residual voltage and analyzes the data.
i. Repeating the a-h process, exploring the acquired data under the conditions of different sizes of the electrode shell pores and angles when the cavities are placed, and analyzing the relationship between the pulse energy and the cracking direction and the electrode shell pores.
The invention has the beneficial effects that:
(1) According to the electrode structure, pulse energy release under different conditions can be realized only by replacing a part of the electrode shell, the previous way of spherical energy release is changed, energy is focused to a certain position and released in a certain direction, and the requirement of directional fracturing in the engineering field can be met;
(2) Impact energy can be analyzed according to data obtained by monitoring the ultra-dynamic strain gauge, and the relationship between the change of electrode gaps, conductive solution and the like and pulse energy under the condition of the empty holes of the electrode shell can be monitored;
(3) The device can also be applied to a true triaxial pressure test, the electrodes are arranged in the material sample, the true triaxial press is utilized to simulate the stress of the true working condition environment, the optimal parameters can be explored, and a new technology is provided for the field of underground coal mining energy.
Drawings
FIG. 1 is a schematic view of an electrode assembly for focusing shock wave energy under the electro-hydraulic effect of the present invention;
FIG. 2 is a schematic view of the attachment position of a strain gage on the side of a granite sample in an example of the invention;
FIG. 3 is a view of the electrode structure of the present invention;
FIG. 4 is a central axis cross-sectional view of FIG. 3;
FIG. 5 is a schematic illustration of different sizes of electrode housing voids; (a) The size of the hollow hole is 2mm multiplied by 10mm, and (b) the size of the hollow hole is 5mm multiplied by 10mm;
FIG. 6 is a high voltage electrode detail view;
FIG. 7 is a ground electrode detail view;
FIG. 8 is a detail view of a polypropylene insulating collar;
in the figure: the device comprises a charging power supply 1, a current-limiting protection resistor 2, an energy storage capacitor 3, an air gap switch 4, a discharge electrode 5, an upper cover plate 6, a sample 7, a strain gauge 8, a lower cover plate 9, a super-dynamic strain gauge 10, a high-voltage electric pulse switch device 11, a power switch 12, a high-voltage electrode thread upper end 13, a fixing nut 14, a polypropylene insulating lantern ring 15, a fixing ring 16, a rubber gasket 17, an electrode shell 18, a high-voltage electrode tip 19, an electrode shell hollow hole 20, a grounding electrode tip 21 and a grounding electrode thread lower end 22.
Detailed Description
The present invention is further illustrated by, but is not limited to, the following examples.
Example (b):
as shown in fig. 1-8, an electrode structure capable of focusing shock wave energy comprises a high voltage electrode, a grounding electrode, a polypropylene insulating collar, a rubber gasket, an electrode shell, a fixing nut and a fixing ring;
the upper end of the high-voltage electrode is provided with threads, the middle part of the high-voltage electrode is connected and fixed with a polypropylene insulating lantern ring 15 through a fixing nut 14, the high-voltage electrode is positioned in the polypropylene insulating lantern ring 15, the polypropylene insulating lantern ring 15 is fixed on the upper part of an electrode shell 18, and the polypropylene insulating lantern ring 15 is fixedly connected with the electrode shell 18 through a fixing circular ring 16; a rubber gasket 17 is sleeved at the contact part of the polypropylene insulating lantern ring 15 and the electrode shell 18; the contact tightness of the two is increased;
the grounding electrode is fixed at the lower end of the electrode shell 18 through threads; the grounding electrode is screwed in through the threads at the bottom of the electrode shell 18 and then is fixed by using the fixing nut 14;
the distance between the grounding electrode and the high-voltage electrode is adjusted by rotating the lower end thread of the grounding electrode through the opposite arrangement of the high-voltage electrode and the grounding electrode in the hollow hole 20 of the electrode shell (the hollow hole 20 is a hole drilled in the electrode shell 18), and the distance between the two electrodes is set to be 1mm-5mm.
Specifically, the total length of the high-voltage electrode is 74mm, and the high-voltage electrode consists of three parts, namely an upper end, a middle end and a lower end, wherein the upper end is a cylinder with the diameter of 4mm and the length of 70mm, the upper end is a part exposed on the polypropylene insulating lantern ring 15, the middle end is a part in the polypropylene insulating lantern ring 15, and the lower end is a part exposed under the polypropylene insulating lantern ring 15 (the lower part of the polypropylene insulating lantern ring 15 is positioned in the electrode shell 18); turning M8 threads with the length of 25mm at the top of the high-voltage electrode, and processing the threads into the upper end 13 of the high-voltage electrode threads; the middle end is a cylinder with the diameter of 5mm and the length of 2mm, and the chamfer angle with the length of 1mm at the lower part is 30 degrees; the lower end is a cylinder with the diameter of 2mm and the length of 2mm, and the bottom is chamfered into a tip with the angle of 45 degrees.
The grounding electrode consists of a smooth cylinder and a threaded cylinder; the diameter of the smooth cylinder of the upper half part is 2mm, the length of the smooth cylinder is 3mm, and the top chamfer angle is a tip end of 45 degrees; the lower half part is a threaded cylinder of M8, and the length is 17mm.
The polypropylene insulating lantern ring is a cylinder with the diameter of 8mm and the length of 95 mm; the diameter of the built-in cavity is 4mm; at a distance of 35mm from the upper top, a polypropylene ring of 12mm diameter and 4mm length was added, which served to secure it to the electrode casing.
The electrode shell is cylindrical in appearance, the inside of the electrode shell is hollow (an electrode penetrates through the electrode shell), the electrode shell is composed of three sections of cylinders with different outer diameters, a first section of cylinder (the outer diameter is 14mm, the inner diameter is 8mm, and the height is 12 mm) at the upper part is connected with the fixed ring, a rubber gasket (the outer diameter is 16mm, the inner diameter is 10mm, and the height is 2 mm) is arranged inside a second section of cylinder (the outer diameter is 22mm, the inner diameter is 8mm, and the height is 3 mm) at the middle part, and the outer side of a third section of cylinder (the outer diameter is 10mm, the inner diameter is 8mm, and the height is 62 mm) at the lower part is of a smooth structure; the first section of cylinder of the electrode shell is provided with external threads (M14 external threads with the height of 10 mm) for connecting a fixed ring 16; the center of the top of the first section of the cylinder is provided with a step hole (the diameter of the upper hole of the step hole is 12mm, the height of the step hole is 2mm, the diameter of the lower hole of the step hole is 8 mm), and the upper part of the step hole is connected with a polypropylene insulating lantern ring 15; the bottom in the second section of cylinder is provided with a hole for placing a rubber gasket 17; an internal thread (M8) is arranged at the center of the bottom of the third section of the cylinder and used for fixing the grounding electrode, and an electrode shell hollow hole 20 is arranged on the cylindrical surface above the third section of the cylinder and exposes the electrode.
One or more of the electrode shell holes 20 are arranged, the cross section of each electrode shell hole is rectangular, and the sizes of the electrode shell holes are 2mm multiplied by 10mm, 3mm multiplied by 10mm or 5mm multiplied by 10mm (which refers to the cross section size corresponding to the front view of the drilled hole); only one hollow hole can be drilled at the bottom of the third cylinder of the electrode shell, and two hollow holes (correspondingly arranged in the front and the back of the electrode) or three hollow holes (three hollow holes are drilled along a 120-degree direction line) can also be drilled. The direction of the shock wave of the electrode structure is controllable, and the energy is focused through a hollow hole arranged at the lower end of the electrode shell.
The diameter 22mm, the length 13mm of the fixed ring 16 of being connected with electrode shell upper end, the inside screw thread that is 11mm, diameter for M13 that is equipped with of fixed ring 16, bore at the fixed ring top and get the round hole that the diameter is 8mm for the insulating lantern ring of polypropylene passes.
The invention also provides an electrode device which is made by adopting the electrode structure and can focus shock wave energy under the hydro-electric effect, and the electrode device comprises a charging power supply 1, an energy storage capacitor 3, a current-limiting protection resistor 2, a power supply switch 12, a high-voltage electric pulse switch 11, a gas gap switch 4, a super-dynamic strain gauge 10 and an electrode structure; the electrode structure is placed in a rock drilling hole, and the charging power supply 1, the power switch 12, the current-limiting protection resistor 2, the energy storage capacitor 3, the gas gap switch 4, the discharge electrode 5, the ultra-dynamic strain gauge 10 and the high-voltage electric pulse switch 11 are structurally connected through the high-voltage cable in sequence.
When the electrode device is used, the electrode device is placed in a sample (namely a cavity drilled by rock), the sample is a granite sample with the thickness of 100mm multiplied by 100mm, 150mm multiplied by 150mm and 300mm multiplied by 300mm, one surface of the granite sample is selected, and a cylindrical cavity with the diameter of 12mm and the length of 75mm is drilled at the center of the granite sample and used for injecting a conductive solution and placing an electrode structure. In order to make the electrode structure closely contact with the cavity, a sealing gasket is arranged at the bottom of the electrode circular ring and used for achieving the effect of sealing the electrode and the rock material cavity.
The invention provides application of the electrode device capable of focusing shock wave energy under the liquid-electric effect, which comprises the following steps:
the conductive liquid is injected into the granite cavity, and different types of solutions can be used, such as tap water, naCl solutions with different concentrations, caCl with different concentrations 2 Solution, alCl of different concentrations 3 A solution; the concentration of the latter three conductive liquids can be tested by adopting five gradients of 1mol/L, 1.5mol/L, 2mol/L, 3mol/L and 5 mol/L;
pasting strain gauges on two sides of a sample, selecting two models of BFH120-80AA-D150 and BFH120-20AA-D150, selecting one surface in the same direction with the pore space of an electrode shell, pasting two BFH120-20AA-D150 strain gauges, selecting a central line to be arranged on the upper part and the lower part, pasting one BFH120-80AA-D150 strain gauge on a symmetrical plane, selecting the position in the center, pasting one BFH120-20AA-D150 strain gauge on the rock wall surface in the direction vertical to the pore space of the electrode shell, wherein the position is the same as that of the strain gauge at the upper position in the same model;
connecting a super-dynamic strain gauge 10 with a strain gauge 8 to acquire the frequency during high-voltage pulse discharge; when the two electrodes are conducted in the sealed cavity, shock waves generated by the conduction of the two electrodes can be collected and analyzed through the ultra-dynamic strain gauge 10, and the correlation between the size and the direction of the electrode shell cavity and the pulse propagation direction and frequency under the condition of conducting liquid is researched, so that the relationship between the size and the direction of the electrode cavity and the shock wave energy release and propagation direction is explored.
The application specifically comprises the following steps:
a. the test material selects a granite sample with the diameter of 150mm multiplied by 150mm, and a cavity cylinder with the diameter of 12mm and the length of 75mm is drilled at the positive center of one surface.
b. Randomly selecting the axis position of one side surface, and pasting a strain gauge with the model of BFH120-20AA-D150, wherein the pasting position is selected at the positions 75mm and 120mm away from the lower bottom surface; a strain gauge with the model of BFH120-80AA-D150 is stuck to the other opposite side surface, and the sticking position is selected to be 75mm away from the bottom surface; and a strain gauge of BFH120-20AA-D150 is stuck to the other adjacent side face, and the position of the strain gauge is the same as that of the strain gauge with the distance of 75mm from the adjacent side face.
c. The high-voltage electrode is placed in a cavity of the polypropylene insulating lantern ring, and the upper end of the high-voltage electrode is fixed by a nut; placing a polypropylene insulating lantern ring in the electrode cavity; in order to ensure good sealing performance, a rubber gasket is sleeved at the contact part of the ring of the insulating lantern ring and the electrode shell and then is connected and fixed by a fixing ring; the grounding electrode is screwed into the bottom of the electrode shell through threads, the distance between the high-voltage electrode and the grounding electrode is adjusted, the electrode distance can be 1mm-5mm, 2mm is selected as a discharge gap in the step, and the grounding electrode is fixed by a fixing nut after the gap distance is adjusted.
d. The size of the electrode shell hollow hole can be 5mm multiplied by 10mm of through hollow hole. The direction of the electrode shell hollow hole is consistent with the horizontal connecting line direction of the two BFH120-20AA-D150 type strain gauges and the BFH120-80AA-D150 type strain gauge.
e. Injecting a conductive solution into a cavity drilled by granite, wherein the conductive solution selected in the step is tap water; the assembled electrode was placed inside the sample cavity. In order to enhance the sealing effect, a sealing washer is arranged at the bottom of the circular ring of the electrode shell, and the tightness between the electrode and the granite cavity is improved by the sealing washer.
f. The electrode and the granite sample are assembled and fixed by utilizing the upper cover plate and the lower cover plate, and the tightness of the sample, the electrode and the cover plate is fixed by rotating nuts at four top corners of the upper cover plate and the lower cover plate. The upper end of the high-voltage electrode is connected with a high-voltage cable, and the upper cover plate and the fixed ring of the electrode are connected with a grounding cable.
g. And connecting the fixed electrode and the sample to a high-voltage pulse discharge device, and respectively connecting the adhered strain gauges to an acquisition port of the ultra-dynamic strain gauge.
h. The high-voltage cable structurally connects the charging power supply 1, the power switch 12, the current-limiting protection resistor 2, the energy storage capacitor 3, the gas gap switch 4, the discharge electrode 5, the ultra-dynamic strain gauge 10 and the high-voltage electric pulse switch 11 in sequence, the ultra-dynamic strain gauge is started firstly, the power switch is turned on, the voltage value of the charging power supply is observed, the charging voltage can be selected according to actual conditions, the range of 5kV to 20kV can be preliminarily selected, after the voltage value is reached, the power switch is turned off, and the high-voltage pulse switch is turned on to discharge. And after the discharge is finished, the ultra-dynamic strain gauge stops collecting data, leaks residual voltage and analyzes the data.
i. Repeating the a-h process, exploring the acquired data under the conditions of different sizes of the electrode shell pores and angles when the cavities are placed, and analyzing the relationship between the pulse energy and the cracking direction and the electrode shell pores.
The focusing and directional releasing effect of the energy generated during the electrode discharging can be achieved only by replacing the electrode shell. Because different energy focusing can be realized by different electrode shell holes, the electrode shell can be replaced.
Claims (10)
1. An electrode structure capable of focusing shock wave energy, characterized in that: the electrode structure comprises a high-voltage electrode, a grounding electrode, a polypropylene insulating lantern ring, a rubber gasket, an electrode shell, a fixing nut and a fixing ring;
the upper end of the high-voltage electrode is provided with threads, the middle part of the high-voltage electrode is connected and fixed with a polypropylene insulating lantern ring through a fixing nut, the high-voltage electrode is positioned in the polypropylene insulating lantern ring, the polypropylene insulating lantern ring is fixed on the upper part of the electrode shell, and the polypropylene insulating lantern ring is fixedly connected with the electrode shell through a fixing circular ring; a rubber gasket is sleeved at the contact part of the polypropylene insulating lantern ring and the electrode shell; the contact tightness of the two is increased;
the grounding electrode is fixed at the lower end of the electrode shell through threads; the grounding electrode is screwed in through the thread at the bottom of the electrode shell and then is fixed by using a nut;
the high-voltage electrode and the grounding electrode are oppositely arranged in the hollow hole of the electrode shell, the distance between the grounding electrode and the high-voltage electrode is adjustable by rotating the lower end thread of the grounding electrode, and the distance between the two electrodes is set to be 1mm-5mm.
2. The electrode structure of claim 1, wherein: the total length of the high-voltage electrode is 74mm, the high-voltage electrode consists of an upper end, a middle end and a lower end, the upper end is a cylinder with the diameter of 4mm and the length of 70mm, and M8-sized threads with the length of 25mm are lathed at the top of the cylinder and are processed into the upper end of the high-voltage electrode threads; the middle end is a cylinder with the diameter of 5mm and the length of 2mm, and the chamfer angle with the length of 1mm at the lower part is 30 degrees; the lower end is a cylinder with the diameter of 2mm and the length of 2mm, and the bottom is chamfered to be a tip end of 45 degrees.
3. The electrode structure of claim 1, wherein: the grounding electrode consists of a smooth cylinder and a threaded cylinder; the diameter of the smooth cylinder of the upper half part is 2mm, the length is 3mm, and the top chamfer angle is a tip of 45 degrees; the lower half part is a threaded cylinder of M8, and the length is 17mm.
4. The electrode structure of claim 1, wherein: the polypropylene insulating lantern ring is a cylinder with the diameter of 8mm and the length of 95 mm; the diameter of the built-in cavity is 4mm; at a distance of 35mm from the upper top, a polypropylene ring of 12mm diameter and 4mm length was added, which served to secure it to the electrode housing.
5. The electrode structure of claim 1, wherein: the electrode shell is cylindrical in appearance, hollow in interior, an electrode penetrates through the electrode shell, the electrode shell is composed of three sections of cylinders with different outer diameters, a first section of cylinder at the upper part is connected with the fixed ring, a rubber gasket is arranged in a second section of cylinder at the middle part, and the outer side of a third section of cylinder at the lower part is of a smooth structure; the first section of cylinder of the electrode shell is provided with external threads for connecting a fixed ring; the center of the top of the first section of the cylinder is provided with a step hole, and the upper hole of the step hole is connected with a polypropylene insulating lantern ring; the bottom in the second section of cylinder is provided with a hole for placing a rubber gasket; the center of the bottom of the third section of cylinder is provided with internal threads for fixing a grounding electrode, and a cylindrical surface above the third section of cylinder is provided with an electrode shell hole for exposing the electrode;
the fixed ring is internally provided with threads, a round hole with the diameter of 8mm is drilled at the top of the fixed ring, and the polypropylene insulating lantern ring penetrates through the round hole.
6. The electrode structure of claim 5, wherein: one or more of the electrode shell holes are arranged, the cross section of each electrode shell hole is rectangular, and the size of each electrode shell hole is 2mm multiplied by 10mm, 3mm multiplied by 10mm or 5mm multiplied by 10mm; drilling a hollow hole at the bottom of the third section of the cylinder of the electrode shell, or symmetrically arranging two hollow holes in front and back or uniformly distributing three hollow holes along the circumference; the size and the position of the hollow hole are set to realize the shock wave direction controllability and the energy focusing of the electrode structure.
7. An electrode device for focusing shock wave energy under the hydro-electric effect using the electrode structure of any one of claims 1~6, wherein: the device comprises a charging power supply, an energy storage capacitor, a current-limiting protection resistor, a power switch, a high-voltage electric pulse switch, a gas gap switch, a super-dynamic strain gauge and an electrode structure; the electrode structure is placed in a cavity of a rock sample, and a charging power supply, a power switch, a current-limiting protection resistor, an energy-storage capacitor, an air gap switch, a discharge electrode, a super-dynamic strain gauge and a high-voltage electric pulse switch structure are sequentially connected by a high-voltage cable;
selecting a granite sample with the thickness of 100mm multiplied by 100mm, 150mm multiplied by 150mm and 300mm multiplied by 300mm on the rock sample, selecting one surface of the granite sample, drilling a cylindrical cavity with the diameter of 12mm and the length of 75mm at the positive center position, and injecting a conductive solution and placing an electrode structure; in order to make the electrode structure closely contact with the cavity, a sealing gasket is arranged at the bottom of the electrode circular ring and used for achieving the effect of sealing the electrode and the rock material cavity.
8. Use of an electrode device according to claim 7 for focusing shock wave energy under the hydro-electric effect, wherein:
the conductive liquid is injected into the granite cavity, and different types of solutions can be used; pasting strain gauges on two sides of a sample, selecting two models of BFH120-80AA-D150 and BFH120-20AA-D150, selecting one surface in the same direction with the electrode shell pore space to paste two BFH120-20AA-D150 strain gauges, selecting the position to paste one center line on the other, pasting one BFH120-80AA-D150 strain gauge on the symmetrical surface, selecting the position in the middle, pasting one BFH120-20AA-D150 strain gauge on the rock wall surface vertical to the electrode shell pore space direction, wherein the position is the same as the strain gauge at the upper position in the same model;
connecting a super-dynamic strain gauge with a strain gauge to acquire the frequency during high-voltage pulse discharge; when the two electrodes are conducted in the sealed cavity, shock waves generated by the conduction of the two electrodes can be collected and analyzed through the ultra-dynamic strain gauge, and the correlation between the size and the direction of the electrode shell cavity and the pulse propagation direction and frequency under the condition of conducting liquid is researched, so that the relationship between the size and the direction of the electrode cavity and the shock wave energy release and propagation direction is explored.
9. Use of an electrode device for focusing shock wave energy under an electro-hydraulic effect according to claim 8, wherein: the method comprises the following steps:
a. the test material is prepared by selecting a granite sample with the thickness of 100mm multiplied by 100mm, 150mm multiplied by 150mm or 300mm multiplied by 300mm, drilling a cylindrical cavity hollow hole at the right center of the surface of the sample, wherein the size of the hollow hole is determined according to the diameter and the length of an electrode;
b. randomly selecting the axis position of one side surface of the sample, sticking two strain gauges, and selecting one strain gauge above one strain gauge and one strain gauge below the other strain gauge; a strain gauge is pasted on the other opposite side surface, and the pasting position is selected to be horizontal to the electrode gap; a strain gauge is stuck to the other adjacent side face, and the position of the strain gauge is horizontal to the electrode gap;
c. the high-voltage electrode is placed in a cavity of the polypropylene insulating lantern ring, and the upper end of the high-voltage electrode is fixed by a nut; placing a polypropylene insulating lantern ring in the cavity of the electrode; in order to ensure good sealing performance, a rubber gasket is sleeved at the contact part of the ring of the insulating lantern ring and the electrode shell and then is connected and fixed by a fixing ring; the grounding electrode is screwed into the bottom of the electrode shell through threads, the distance between the high-voltage electrode and the grounding electrode is adjusted to be 1-5 mm, and the grounding electrode is fixed by a fixing nut after the gap distance is adjusted;
d. the size of the hollow hole of the electrode shell is 2mm multiplied by 10mm, 4mm multiplied by 10mm or 5mm multiplied by 10mm, and one hollow hole, two hollow holes or three hollow holes are selected to form different electrode structures;
e. injecting conductive solution into a cavity drilled by granite, using different types of conductive solution, placing a sealing washer at the bottom of a ring of an electrode shell in order to enhance the sealing effect, and improving the tightness between an electrode and the granite cavity by using the sealing washer;
f. assembling and fixing the electrode and the granite sample by utilizing the upper cover plate and the lower cover plate, and fixing the sample, the electrode and the tightness degree of the cover plate by rotating nuts at four top corners of the upper cover plate and the lower cover plate; the upper end of the high-voltage electrode is connected with a high-voltage cable, and the upper cover plate and the fixed ring of the electrode are connected with a grounding cable;
g. connecting the fixed electrode and the sample to a high-voltage pulse discharge device, and respectively connecting the adhered strain gauges to an acquisition port of the ultra-dynamic strain gauge;
h. the high-voltage cable sequentially connects a charging power supply, an energy storage capacitor, a current-limiting protection resistor, a power switch, a high-voltage electric pulse switch, an air gap switch and an ultra-dynamic strain gauge electrode structure, the ultra-dynamic strain gauge is started, the power switch is turned on, the voltage value of the charging power supply is observed, the charging voltage is selected according to actual conditions, the range of 5kV to 20kV is selected, and when the voltage value is reached, the power switch is turned off, and the high-voltage pulse switch is turned on for discharging; after the discharge is finished, the ultra-dynamic strain gauge stops collecting data, residual voltage is leaked, and the data are analyzed;
i. repeating the a-h process, exploring the acquired data under the conditions of different sizes of the electrode shell holes and angles when the cavities are placed, and analyzing the relation between the pulse energy size and the cracking direction and the electrode shell holes.
10. Use of an electrode device for focusing shock wave energy under an electro-hydraulic effect according to claim 9, wherein: the conductive solution comprises tap water, naCl solution and CaCl 2 Solutions or AlCl 3 A solution; the concentration of the three salt solutions is tested by taking five gradients of 1mol/L, 1.5mol/L, 2mol/L, 3mol/L and 5 mol/L.
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| CN115930690A (en) * | 2022-11-22 | 2023-04-07 | 山东大学 | Bunching shock wave rock crushing device and method based on bubble-guided underwater discharge |
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