A linear multi-stage series arc discharge water sound generating device

Abstract

The present invention discloses a linear multi-stage series arc discharge water sound generating device, comprising a supporting fixture and a plurality of wire electrode series sequences arranged in parallel on the supporting fixture; each wire electrode series sequence comprises a plurality of wire electrodes arranged at equal intervals along a straight line, and each wire electrode comprises a middle metal conductor and an outer insulating layer; the two ends of the plurality of wire electrode series sequences are respectively connected to a high-voltage end and a low-voltage end; the high-voltage end is connected to the high-voltage part of a pulse cable to realize high-voltage electric pulse input; the low-voltage end is connected to the low-voltage part of a pulse cable to constitute the low-voltage part of a discharge circuit to realize the conduction of the entire discharge circuit. By using the present invention, the electroacoustic efficiency can be further improved, the transmitting device can be made stable and reliable, and the life of the electrode can be improved.

Description

Technical Field

[0001] The invention belongs to the field of marine seismic exploration, and in particular relates to a linear multi-stage series arc discharge water sound generating device. Background Art

[0002] Marine high-resolution seismic exploration is an important technical means to achieve the development and utilization of marine resources and territorial security. The seismic source, as a launching device for seismic exploration, is of vital importance. So far, many types of seismic sources have been used, mainly including explosive seismic sources, air guns, water guns, BOOMER seismic sources, spark seismic sources, etc. Among them, the spark seismic source is based on the "liquid-electric effect", that is, the conversion of electrical energy into acoustic energy is achieved through high-voltage pulse discharge in water.

[0003] Conventional spark generators, based on arc discharge in water, such as Figure 1 As shown in (a). A head-to-head electrode pair structure is usually used. During the discharge process, a spark channel is generated in the electrode gap. The load impedance is as low as a few mΩ to tens of mΩ. The instantaneous power and current of the discharge are very large, and the intensity of the generated acoustic pulse is large, but the electrode life is generally low. At the same time, due to the high salinity and conductivity of seawater, the electroacoustic effect of arc discharge is significantly weakened compared to low-salinity water. At the same time, the repetition of the excited acoustic pulse is poor, which is not conducive to high-resolution seismic exploration. Therefore, it is gradually replaced by corona discharge. The principle is as follows Figure 1 As shown in (b).

[0004] Corona discharge is a local discharge, which can generally produce a good electroacoustic effect in high salinity or high conductivity water. Therefore, it is very suitable for marine seismic exploration and has become the mainstream technology at home and abroad. Foreign sources mainly include the seismic source developed by GEOMarine Survey Systems of the Netherlands, the SIG seismic source of France and the spark seismic source developed by GeoAcoustics of the United Kingdom. Domestically, the new spark seismic source developed by Zhejiang University is mainly corona discharge, which has a low voltage level and much smaller instantaneous power than arc discharge. The discharge and acoustic pulse repeatability are excellent, and the electrode life is long, generally reaching 3-5 years. However, the electroacoustic conversion efficiency of this discharge form is low, generally not higher than 5%.

[0005] Therefore, based on the corona discharge, the European Union patent document with publication number EP2804018 proposed a bipolar discharge technology, such as Figure 1As shown in (c). The so-called bipolar discharge is to change the ground electrode into a wire electrode. At the same time, the distance between the electrode tips is long, and no arc channel can be generated. It inherits the advantage of long life of corona discharge electrodes. During the discharge process, since the current in the load must enter from the tip of the ground electrode, the current density at the tip of the ground electrode is very high at this time, so it will vaporize the surrounding water and produce bubbles that expand at a high speed, thus also generating acoustic pulses. Compared with single-electrode corona discharge, additional acoustic pulses are generated at the ground end, which improves the electroacoustic efficiency.

[0006] As mentioned above, the electroacoustic efficiency of arc discharge is generally high, which can exceed 10%. Therefore, in order to learn from its high electroacoustic efficiency, a Chinese patent document with publication number CN105676293A proposes a microporous electrode structure, such as Figure 1 As shown in (d). The overall structure is consistent with corona discharge, which belongs to local discharge at the high-voltage end, but the high-voltage electrode metal is not exposed, but embedded in the insulating layer, and connected to the external water body and the grounding electrode through the micropores on the insulating layer. Since the micropores can maintain a uniform and high field strength, the water in the micropores is first heated, and an arc channel is generated in the micropores after vaporization. Part of the discharge energy accumulates in the micropores. When the bubbles expand from the micropores, a strong sound pulse is immediately generated. The intensity is significantly higher than that of corona discharge, which effectively improves the electroacoustic efficiency. Of course, micropore discharge places higher requirements on the strength and life of the insulating medium, so the cost is higher. Summary of the invention

[0007] The present invention provides a linear multi-stage series arc discharge water acoustic generating device, which can further improve the electroacoustic efficiency, make the transmitting device stable and reliable, and increase the life of the electrode.

[0008] The technical solution of the present invention is as follows:

[0009] A linear multi-stage series arc discharge hydroacoustic generating device, comprising a supporting fixture and a plurality of series-connected wire electrode sequences arranged in parallel on the supporting fixture; each series-connected wire electrode sequence comprises a plurality of wire electrodes arranged at equal intervals along a straight line, and each wire electrode comprises a metal conductor in the middle and an insulating layer outside; two ends of the plurality of series-connected wire electrode sequences are connected to a high-voltage end and a low-voltage end respectively;

[0010] The high-voltage end is connected to the high-voltage part of the pulse cable to realize high-voltage electrical pulse input; the low-voltage end is connected to the low-voltage part (or grounded part) of the pulse cable to constitute the low-voltage part of the discharge circuit to realize the conduction of the entire discharge circuit.

[0011] Furthermore, each group of wire electrode series sequences is fixed on the supporting and fixing device through a wire electrode sequence fixing bracket.

[0012] The wire electrode sequence fixing bracket includes a crossbar and an electrode clamp, wherein the crossbar is fixed on the supporting fixing device, and each wire electrode is fixed on the crossbar through the electrode clamp. The crossbar and the electrode clamp are generally made of stainless steel or titanium alloy to reduce the overall weight.

[0013] Furthermore, the wire electrode series sequence is used to generate strong multi-stage series arc discharge, and the gap between two adjacent wire electrodes generates an arc channel. Each arc channel can distribute and consume energy up to 100J, which significantly improves the energy density of the sound-generating device.

[0014] In each electrode unit, in order to improve strength and hardness and reduce electrode ablation caused by arc discharge, the preferred material of the middle metal conductor is tungsten steel, and the optional electrode material is stainless steel, and the diameter is generally ≤2mm.

[0015] The insulating layer is generally made of materials such as polytetrafluoroethylene or polyurethane to ensure that only the head of the metal conductor is exposed and the diameter is ≤10mm.

[0016] In addition, to ensure the effective occurrence of arc discharge and generate sufficient acoustic intensity, the interval between electrode units in each set of wire electrode series sequence is ≤5mm.

[0017] Furthermore, the supporting and fixing device ensures the floating potential and does not constitute a component of the discharge circuit. The supporting and fixing device is made of stainless steel or titanium alloy material to reduce the overall weight.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The hydroacoustic generator of the present invention inherits the advantages of arc discharge and bipolar discharge, significantly improves the electroacoustic efficiency, and significantly improves the energy density of the hydroacoustic generator. In addition, it avoids the problem of short life of the microporous discharge insulation layer, significantly improves the service life of the electrode, and further optimizes the performance and detection capability of the hydroacoustic generator based on underwater discharge technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The different underwater pulse discharge electrode structures mentioned in the background technology of the present invention;

[0021] Figure 2 It is a schematic structural diagram of a linear multi-stage series arc discharge water sound generating device of the present invention;

[0022] Figure 3 A structural diagram of a series of wire electrodes in an embodiment of the present invention;

[0023] Figure 4 It is the result of high-speed photography of the multi-stage series arc discharge process in the embodiment of the present invention.

[0024] In the figure: 1-high voltage end, 2-low voltage end, 3-line electrode series sequence, 4-support fixture, 31-metal conductor, 32-insulating layer, 33-electrode fixing fixture, 34-cross bar. DETAILED DESCRIPTION

[0025] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be pointed out that the embodiments described below are intended to facilitate the understanding of the present invention and do not have any limiting effect on the present invention.

[0026] like Figure 2 As shown, a linear multi-stage arc discharge hydroacoustic generating device comprises a high voltage end 1, a low voltage end 2, N groups of wire electrode series sequences 3 and a supporting fixture 4; the high voltage end 1 and the low voltage end 2 are both equipotential interfaces. Multiple groups of wire electrode series sequences 3 are arranged in parallel on the supporting fixture 4.

[0027] The two ends of the multiple sets of wire electrode series sequence 3 are respectively connected to the high voltage end 1 and the low voltage end 2. The electric pulse is input through the high voltage end 1, and the multiple sets of wire electrode series sequence 3 completes the underwater arc discharge to achieve the acoustic pulse output, and then completes the pulse current reflux through the low voltage end 2, and finally forms a discharge loop.

[0028] The supporting and fixing device 4 is used to fix the N groups of line electrode series sequence 3, while ensuring the floating potential, and does not constitute a part of the discharge circuit.

[0029] like Figure 3 As shown, each group of line electrode series sequence 3 includes a plurality of line electrodes arranged at equal intervals along a straight line, each line electrode includes a middle metal conductor 31 and an outer insulating layer 32 , and the heads of both ends of the metal conductor 31 are exposed outside the insulating layer 32 .

[0030] Each group of wire electrode series sequence 3 is fixed on the support fixture by a wire electrode sequence fixing bracket. The wire electrode sequence fixing bracket is used to fix the M groups of wire electrodes to ensure that the wire electrodes maintain a good linear series structure.

[0031] The wire electrode series sequence 3 is used to generate strong multi-stage series arc discharge. When there are M wire electrodes, M-1 arc channels can be generated. Each arc channel can distribute and consume up to 100J of energy, which will significantly improve the energy density of the sound-generating device.

[0032] like Figure 3 As shown, the wire electrode sequence fixing bracket includes a cross bar 34 and an electrode fixture 33. The cross bar 34 is fixed on the supporting fixture 4, and each wire electrode is fixed on the cross bar 34 through the electrode fixture 33. The cross bar 34 and the electrode fixture 33 are generally made of stainless steel or titanium alloy to reduce the overall weight.

[0033] In this embodiment, in order to improve strength and hardness and reduce electrode ablation caused by arc discharge, the preferred material of the middle metal conductor 31 is tungsten steel, and the optional electrode material is stainless steel, and the diameter is generally not more than 2 mm.

[0034] The insulating layer 32 is made of materials such as polytetrafluoroethylene or polyurethane to ensure that only the head of the metal wire core is exposed, and the diameter is generally not more than 10 mm.

[0035] In addition, to ensure the effective occurrence of arc discharge and generate sufficient acoustic intensity, the electrode gap distance generally does not exceed 5 mm.

[0036] The working principle of the present invention is as follows:

[0037] When the electric pulse is input to the line electrode series sequence 3 through the high-voltage terminal 1, violent arc discharge will not be generated immediately. Due to the multi-stage series structure, the load impedance is relatively large, and the load voltage is maintained at a high level. Since the gap electric field strength of the metal conductor 31 in the middle is large, each gap is connected after the water body is broken down step by step, until the moment when the last discharge gap is turned on, the load impedance is instantly reduced, the electric energy is quickly injected, the instantaneous power is increased, and violent discharge is generated in the middle of each gap, exciting a strong acoustic pulse, and flowing back to the energy storage capacitor through the low-voltage terminal 2.

[0038] like Figure 4 As shown, it is the result of high-speed photography of the multi-stage series arc discharge process in the embodiment of the present invention. In this embodiment, three-stage series discharge electrodes are used as the hydroacoustic generating device. The discharge energy is 30J, and the energy storage capacitor is 2μF. The outer diameter of the discharge electrode insulation layer is 5.5mm, and the diameter of the metal conductor is 1.4mm. The gap is about 1mm. The water temperature is about 15°C, and the conductivity is about 55mS / cm, which is equivalent to seawater. During the implementation process, the discharge process is mainly optically diagnosed by a high-speed camera to verify the feasibility of the discharge. The high-speed camera recording speed is set at 10,000fram / s, and three discharge moments and subsequent bubble expansion are successfully captured, indicating that multi-stage series discharge can occur effectively. Therefore, this embodiment is effective and feasible, and has good application prospects.

[0039] The present invention adopts a linear multi-stage series discharge electrode structure to induce a linear series arc discharge, inheriting the advantages of arc discharge and bipolar discharge, significantly improving the electroacoustic efficiency, and significantly improving the energy density of the hydroacoustic generator. In addition, it overcomes the problem of short life of the microporous discharge insulation layer, significantly improves the service life of the electrode, further optimizes the performance of the hydroacoustic generator based on underwater discharge technology, and improves the detection depth of the electric spark source.

[0040] The embodiments described above provide a detailed description of the technical solutions and beneficial effects of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, supplements and equivalent substitutions made within the scope of the principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A linear multi-stage series arc discharge water sound generating device, characterized in that: It comprises a supporting fixture and a plurality of series-connected wire electrode sequences arranged in parallel on the supporting fixture; each series-connected wire electrode sequence comprises a plurality of wire electrodes arranged at equal intervals along a straight line, and each wire electrode comprises a metal conductor in the middle and an insulating layer outside; two ends of the plurality of series-connected wire electrode sequences are respectively connected to a high-voltage end and a low-voltage end; The high-voltage end is connected to the high-voltage part of the pulse cable to realize the input of high-voltage electric pulses; the low-voltage end is connected to the low-voltage part of the pulse cable to form the low-voltage part of the discharge circuit to realize the conduction of the entire discharge circuit; Each group of wire electrode series sequence is fixed on the support and fixing device through a wire electrode series fixing bracket; the wire electrode series fixing bracket includes a cross bar and an electrode clamp, the cross bar is fixed on the support and fixing device, and each wire electrode is fixed on the cross bar through the electrode clamp; the support and fixing device ensures the floating potential and does not constitute a part of the discharge circuit; in each group of wire electrode series sequence, the interval between electrode units is ≤5mm; The wire electrode series sequence is used to generate strong multi-stage series arc discharge. The gap between two adjacent wire electrodes generates an arc channel. Each arc channel distributes and consumes energy up to 100J, which significantly improves the energy density of the sound-generating device.

2. The linear multi-stage series arc discharge water sound generating device according to claim 1 is characterized in that: In each electrode unit, the material of the metal conductor is tungsten steel or stainless steel, and the diameter is ≤2mm.

3. The linear multi-stage series arc discharge water sound generating device according to claim 1, characterized in that: In each electrode unit, the insulating layer is made of polytetrafluoroethylene or polyurethane to ensure that only the head of the metal conductor is exposed and the diameter is ≤10mm.

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