Vihisi joto vya INNO fiber optic ,mifumo ya ufuatiliaji wa joto.
Definition of Distributed Fiber Optic Acoustic Sensing
Distributed Acoustic Sensing System (THE) is a fiber optic optoelectronic device that measures acoustic interactions along the length of the fiber optic sensing cable.
The unique feature of a distributed acoustic sensing system is that it provides a continuous (or distributed) temperature distribution along the length of the sensing cable, rather than at discrete sensing points.
Distributed acoustic sensing technology
Kwa kawaida, DAS technology uses standard telecommunications fiber optic cables, and specialized fiber optic cables are only required at high temperatures (greater than 100 °C). Sensing fibers are usually based on single-mode fibers, although some specialized applications use multi-mode sensing fibers.
The range of a DAS system is usually up to 50km per sensing fiber, and each inquiry unit usually has 1 au 2 channels that can be operated simultaneously. Kwa mfano, DAS can measure up to 100km, and 2-channel units can measure 50km in any direction.
kanuni ya kipimo
The distributed acoustic sensor interrogation unit transmits laser pulses to the fiber optic. When this type of light pulse propagates along the fiber, the interaction inside the fiber causes light reflection called backscattering, which is determined by small strain (au mtetemo) events inside the fiber, which are caused by local sound energy. This backscattered light propagates upwards along the fiber optic to the interrogation unit, where it is sampled at Rayleigh frequency. Muda unaohitajika kwa mapigo ya leza huruhusu upangaji sahihi wa matukio ya kutawanyika nyuma hadi umbali wa nyuzinyuzi – hii inajulikana kama kiakisi cha kikoa cha macho cha saa.
Mifumo mingi ya hisia za akustisk iliyosambazwa kwenye soko leo inategemea kanuni iitwayo Coherent Optical Time Domain Reflectometer. (COTDR).
Utatuzi wa anga na kipindi cha sampuli za anga
Azimio la anga limedhamiriwa hasa na muda wa pigo lililotolewa, na azimio la 10m lililotolewa na mpigo wa 100ns ni thamani ya kawaida. Kiasi cha mwanga ulioakisiwa ni sawia na urefu wa mpigo, kwa hivyo kuna usawa kati ya azimio la anga na anuwai ya juu. Ili kuboresha upeo wa juu, inategemewa kutumia urefu wa mpigo mrefu ili kuongeza kiwango cha mwanga unaoakisiwa, lakini hii husababisha azimio kubwa zaidi la anga. Kwa kawaida, azimio la anga la mifumo mingi ni 5-10 mita.
Ulinganisho kati ya DAS na zingine mifumo ya kuhisi iliyosambazwa ya fiber optic
Kuna mengine mengi fiber optic iliyosambazwa teknolojia za kuhisi ambazo zinategemea njia tofauti za kutawanya na zinaweza kutumika kupima vigezo vingine..
Mifumo ya msingi ya Brillouin hutumiwa kwa kawaida kupima shinikizo na halijoto iliyosambazwa.
Mtawanyiko wa Brillouin ni dhaifu sana kuliko utawanyiko wa Rayleigh, kwa hivyo uakisi kutoka kwa mipigo mingi lazima iongezwe pamoja ili kuwezesha kipimo. Kwa hiyo, masafa ya juu ya kupima mabadiliko kwa kutumia Brillouin kutawanya kwa kawaida ni makumi kadhaa ya Hz, wakati Rayleigh kulingana na mifumo ya COTDR DAS ina unyeti wa kHz.
Mifumo ya Raman hutumiwa kwa kawaida kupima joto, wakati mifumo ya DTS kwa kawaida inategemea teknolojia ya Raman. The intensity of Raman scattering is even lower than that of Brillouin scattering, so it usually takes an average of many seconds or even a few minutes to obtain reasonable results. Kwa hiyo, Raman based systems are only suitable for measuring slowly changing temperatures.
Data collection, usindikaji wa ishara, and visualization
Due to the large amount of data generated by distributed acoustic sensing systems, it is crucial to have a strategy for management, usindikaji, and data visualization. These systems collect data at speeds above 10 Khz at up to 20 sensing points. This is equivalent to the rate at which terabyte drives can be filled within a few days.
Kwa kawaida, the inquiry unit is connected to the processing unit (industrial PC or server) that manages data storage and processing. Kwa kawaida, there is a scrolling buffer used to store raw data because there is very little content stored beyond this.
The processing unit is programmed using a series of intelligent algorithms to interpret raw data and analyze whether it matches pre-defined events, such as intrusion events or pipeline leaks. The fiber optic sensing cable will be divided into multiple areas, where specific selected algorithms will be selected and alerts will be assigned within each area.
There are many ways to visualize these events. One approach is to use DTS specific visualization software, such as displaying the path of optical fibers based on site maps or charts, and if there are events, it will highlight the location of the events and display alarms. Another approach is for the DAS software interface to be integrated with existing SCADA, kudhibiti, or security software packages. Katika kesi hii, the event will highlight the software of the parties involved in 3.
DAS measurement principle:
Please add a link to describe that DAS is a distributed fiber optic sensor based on coherent Rayleigh scattering. It utilizes the sensitivity of optical fibers to sound (mtetemo). When external vibrations act on the sensing optical fiber, due to the elastic optical effect, the refractive index and length of the optical fiber will undergo slight changes, resulting in a phase change of the transmitted signal inside the optical fiber and a change in light intensity.
The phase change caused by sound waves is very small, so DAS systems usually use highly coherent pulse light sources. Kuingilia hutokea kati ya ishara za kutawanya za Rayleigh ndani ya eneo la upana wa mapigo. Wakati vibration ya nje husababisha mabadiliko ya awamu, ukubwa wa ishara thabiti ya kutawanya Rayleigh katika hatua hiyo itabadilika. Kwa kugundua mabadiliko ya kiwango cha taa ya Rayleigh kabla na baada ya mtetemo. (ishara tofauti), utambuzi wa tukio la mtetemo unaweza kupatikana, na matukio mengi ya mtetemo yanaweza kupatikana kwa usahihi wakati huo huo.
Faida za teknolojia ya DAS:
Upimaji unaoendelea kusambazwa wa halijoto na mtetemo bila vipofu vya kipimo
Ugunduzi wa wakati mmoja na ujanibishaji sahihi wa matukio mengi
Fiber optic ni sensor ambayo inachanganya maambukizi na kuhisi
60 kilomita za umbali mrefu zaidi wa kipimo, habari nyingi za kipimo
Kasi ya majibu ya haraka, kengele ndani 1 pili
Usambazaji wa ishara ya macho, completely electrically insulated, resistant to electromagnetic interference
Usalama wa ndani, suitable for long-term operation in flammable and explosive environments
Stable and reliable measurement with low false alarm rate
Long service life of optical fibers, hadi 30 years maintenance free
DAS performance characteristics:
Long temperature distance: 50km
Muda wa majibu ya haraka: kawaida 1 pili
Usahihi wa nafasi ya juu: 2-50m
Unyeti wa juu: can perceive vibrations within 40m around the optical cable
Simultaneous monitoring of vibration and temperature
Online monitoring function for fiber optic faults
Perceiving all things is an important technological support for building a smart earth, smart city, and smart ocean. Distributed Fiber Optic Acoustic Sensing (THE) teknolojia ni aina mpya ya teknolojia ya kuhisi ambayo inaweza kufikia ugunduzi unaoendelea wa kusambazwa kwa sehemu za vibration na sauti.. Inatumia sifa nyeti sana za mtawanyiko wa Rayleigh unaochochewa na leza nyembamba ya masafa ya mstari mmoja katika nyuzi za macho., pamoja na kanuni ya reflectometer, kutambua mtetemo wa mazingira na habari ya uwanja wa sauti inayoingiliana na nyuzi za macho kwa umbali mrefu na kwa usahihi wa hali ya juu wa anga.. Uwezo huu wa kipekee wa utambuzi wa habari umevutia usikivu mkubwa kutoka kwa wasomi na tasnia kwa teknolojia ya DAS. Utendaji wa teknolojia ya DAS unaendelea kuboreshwa, na matumizi yake yanaendelea kwa kasi. Imeonyesha faida zake za kipekee za kiteknolojia na uwezo katika kugundua uingiliaji wa mzunguko, online monitoring of railway safety, geophysical exploration, and other areas.
Due to its unique advantages, DAS has attracted more and more experts from various fields to seek industry breakthroughs, while also placing increasing demands on the improvement of DAS technology.
After more than a decade of development, DAS has played an irreplaceable role in multiple fields, especially in the application scenarios of long-distance, kwa kiasi kikubwa, and spatiotemporal dense detection, including perimeter security, usafiri, geophysical exploration, ufuatiliaji wa afya ya kimuundo, na nyanja zingine. Researchers are also continuously improving DAS technology to meet the personalized application needs of various fields.
In the field of perimeter security, compared to conventional methods, DAS has advantages such as strong environmental adaptability, high concealment, large monitoring range, and distributed blind spots. Hata hivyo, how to determine what kind of disturbance and intrusion occurred along the fiber optic cable based on the large number of complex signals detected by DAS is a technical challenge.
In the field of railway transportation, DAS technology uses passive optical fibers as sensing and transmission devices, which can achieve spatial continuous sensing of disturbance signals along the fiber optic line. It has the characteristics of anti electromagnetic interference, long-distance distributed measurement, low cost per unit distance, and no need for on-site power supply. It can effectively compensate for the shortcomings of existing point electromagnetic sensing technology, meet the application needs of railway transportation, and can be quickly integrated into existing railway lines. It has been widely applied.
Oil and gas resource exploration is also an important application of DAS technology. The conventional oil and gas resource exploration technology uses point type electronic detectors, which have drawbacks such as low deployment efficiency and long large-scale experimental time. DAS uses conventional communication optical fibers as sensor components, which are low-cost and can play a role throughout the entire life cycle of drilling, completion, uzalishaji, nk., with significant advantages.
Aidha, due to the small size and light weight of optical fibers, ni rahisi kupachikwa katika miundo kama vile vifaa vya mchanganyiko wa anga, vifaa vya ujenzi, vyombo vya habari vya udongo, nk. DAS inaweza kupata kwa urahisi ishara za utoaji wa akustisk ndani ya nyenzo, kufikia ufuatiliaji wa kudumu mtandaoni wa vifaa na miundo.
Mitindo ya maendeleo ya siku zijazo na changamoto
Teknolojia ya DAS imekuwa ikikomaa kila mara, soko la maombi linapanuka, na matarajio yanazidi kushamiri. Hivi majuzi, wasomi wa kigeni wamependekeza kutumia nyuzi za macho zilizopo za mawasiliano ya chini ya ardhi kujenga mtandao mkubwa wa ufuatiliaji wa uchambuzi wa kijiolojia na maafa makubwa ya asili. (tetemeko la ardhi) kugundua. Mwelekeo huu wa ukuzaji unaweza kugusa manufaa ya mtazamo wa angavu wa kiwango kikubwa wa DAS, anzisha tena rasilimali zote za mawasiliano zisizohitajika chini ya ardhi duniani kote, na ina thamani ya juu sana ya soko na uwezo wa maendeleo.
Although DAS technology has made significant progress, it is not yet fully mature and there are still important technical bottlenecks that need to be addressed, mainly including sensitivity improvement, multi-dimensional detection, and new data processing paradigms.
The sensitivity of DAS technology is relatively high compared to distributed sensing technology. Hata hivyo, compared to conventional point sensing technology, there is still a significant gap. To apply DAS technology on a large scale, it is necessary to significantly improve the sensitivity of this technology, making it close to the level of existing point sensing devices, in order to truly replace existing technological means in various application fields.
Wakati huo huo, the existing detection capability of DAS is still limited by the one-dimensional axial structure of optical fibers, and it is difficult to achieve three-dimensional positioning of disturbance sources and multi-component detection of signals, which to some extent limits the technical performance and application scope of DAS. Distributed 2D/3D positioning detection and drone countermeasures based on images
Aidha, umbali mrefu, spatially dense sampling, and time-domain dense sampling features of DAS generate a huge amount of sensing data. How to convert the huge amount of raw data into useful sensing signals in real time requires the development of new data processing methods and algorithms.
Kwa muhtasari, DAS technology provides a revolutionary technological means for the perception of the physical world, which is of great significance for promoting scientific research and the intelligent development of human society.
Sensor ya joto ya fiber optic, Mfumo wa ufuatiliaji wa akili, Kusambazwa fiber optic mtengenezaji nchini China
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