Fiber Optic Temperature Measurement System Research Articles

Single optical channel based Raman distributed optical fiber temperature measurement system

Single optical channel based Raman distributed optical fiber temperature measurement system

Optimization of the Monitoring of Coal Spontaneous Combustion Degree Using a Distributed Fiber Optic Temperature Measurement System: Field Application and Evaluation

Coal spontaneous combustion (CSC) in gob not only leads to wasted resources and casualties, but also produces a lot of waste gas that pollutes the underground environment. Mastering the degree of CSC helps ensure that timely and effective control measures are taken. The real-time and accurate monitoring of temperature, as the primary indicator of the extent of CSC, is difficult due to the harsh and hidden environment of gob, resulting in a reduced ability to anticipate and prevent CSC. In this work, a complete distributed optical fiber temperature sensing system (DTSS) set with strong anti-damage ability was developed. The optical cable is protected by internal parallel steel cables and external protective pipes, which greatly improve the system’s reliability and integrity when used in gob. During its application in the Wangyun Coal Mine, an abnormal temperature rise in gob was discovered in time, and the effect of inhibitor spraying was monitored and evaluated. The degree of CSC in the gob was accurately identified, which shows that the work of coal mining can be targeted. This work is expected to improve early warning capability to prevent the risk of CSC in gob, and has promising applications.

Leakage Monitoring and Quantitative Prediction Model of Injection–Production String in an Underground Gas Storage Salt Cavern

The leakage of the injection–production string is one of the important hidden dangers for the safe and efficient operation of underground salt cavern gas storage. Although distributed fiber optic temperature measurement system (DTS) can accurately locate the position of the string leakage port, how to establish the quantitative relationship between the temperature difference and leakage rate of the leakage port still needs further exploration. This paper proposes a new quantitative prediction model based on a DTS for the leakage monitoring of the injection–production string of salt cavern gas storage. The model takes into account the gas’s physical parameters, unstable temperature conditions, and the Joule–Thomson effect. In order to verify the accuracy of the model, a simulation experiment of string leakage based on a DTS was carried out. The test results show that the relative deviation between the predicted leakage rate and the measured value is less than 5% compared with the calculated value. When the leakage rate drops to 0.16 m3/h and the temperature range is less than 0.5 °C, it is difficult to accurately monitor the DTS. The results of this study help to improve the early warning time of underground salt cavern gas storage string leakage.

Conceptual Model, Experiment and Numerical Simulation of Diaphragm Wall Leakage Detection Using Distributed Optical Fiber.

Leakage in the diaphragm wall is difficult to detect in deep foundation pits. In this study, the conceptual model of active and passive thermal leak detection methods was proposed according to the occurrence of temperature field anomalies caused by seepage. Experiments were performed using a heating system and an optical fiber temperature measurement system to verify the thermal leakage detection systems. Numerical simulations were performed to understand the mechanism of the detecting method. Results indicated that the optical cable could detect the low-temperature anomaly in the active temperature field leak detection. The arrangement method of the leakage detection system was also presented in actual engineering.

Design Framework and Laboratory Experiments for Helix and Slinky Type Ground Source Heat Exchangers for Retrofitting Projects

The focus of the experimental work was on shallow spiral geothermal heat exchanger configurations. Real-scale experiments were carried out for vertically oriented spiral collectors (helix) in sand and soil. One objective was to develop a measurement concept in laboratory environment to create a framework for a validated database. This database serves as the basis for further and new development of engineering design tools. To achieve the highest possible data-point density in the observed environment, temperature sensors and a fiber-optic temperature measurement system (DTS) were used. Soil probes were taken in situ before and after the measurements and analyzed at a thermophysical laboratory to determine material properties. The heat flow was controlled by an electric heating cable, which was installed in the form of a spiral-shaped heat exchanger in a 1 m³ container. To guarantee constant boundary conditions, the measurements were carried out in a climate chamber at a defined ambient temperature. The evaluation of the transient response behavior is spatially resolved. The results are coordinate-based temperature points, which describe temperature gradients in all axes of the container over time, which are combined with known soil properties. The collected data was used to develop computational fluid dynamic (CFD) models, which are used to extend the variety of geometry and soil configurations for developing new design tools.

Study on the Law of Influence of Seepage Field Anomalies on Displacement Field Induced by Leakage of Enclosure Structure

The leakage of an enclosure structure will cause abnormal changes in the seepage flow field, which in turn can lead to the deformation of the enclosure structure and affect the surrounding geotechnical body. In this paper, a fiber-optic temperature measurement system is used to detect the location of the seepage points in a station of the Qingdao subway during open pit excavation, and the abnormal variation of the seepage field caused by the seepage points is obtained by numerical calculation and field measurement. Then, numerical simulation is performed to analyze the effects of seepage field anomalies on the deformation of the enclosure structure and surface settlement. It is found that the seepage flow caused by the leakage point has a significant influence on the surface settlement and the deformation of the enclosure structure. With the increase of excavation depth, the deformation of the enclosure structure increases and the maximum deformation position shifts downward. The deformation of the enclosure structure decreases when the leakage point exists. The surface volume also increases gradually with the excavation, and the maximum surface settlement position shifts outward significantly. The settlement range becomes larger when the leakage point exists.

High spatial resolution distributed optical fiber temperature measurement system for ice cover profile

针对现有冬季冰盖垂直剖面温度检测技术的不足，设计了一种具有高空间分辨率的分布式光纤测温系统，介绍了系统的测量原理和总体结构，提出使用反卷积校正算法，避免了因受系统有限带宽影响而导致的测温不准，从而提升空间分辨率。同时进行了相关测温实验。该算法可以在保证温度测量精度的前提下，将系统的空间分辨率从1.3 m提升至0.5 m。设计了一种具有垂直高分辨率的温度测量装置，可以精确检测冰盖内部垂直方向上的温度变化，实现对冰盖厚度的识别。

Analysis of Current Carrying Capacity of Power Cable Based on DTS

This article uses a distributed optical fiber temperature measurement system (DTS, Distributed Temperature Sensing) to fix the temperature measurement optical fiber on the surface of the power cable, collect the real-time operating temperature of the power cable, conduct the ampacity test, and analyze the cable laying method and depth, soil temperature, Soil thermal resistance coefficient, cable spacing and irradiation strength and other test conditions, the impact on the current carrying capacity of power cables. According to the real-time monitoring temperature of the cable, the alarm can be made when the cable temperature is too high or the temperature rise speed is too fast. And on the basis of determining the working temperature and load operating conditions of the cable conductor core, dynamically calculate the current carrying capacity of the cable, which is conducive to improving the performance of the power cable and increasing the load capacity of the power cable.

A Spatially Distributed Fiber-Optic Temperature Sensor for Applications in the Steel Industry.

This paper presents a spatially distributed fiber-optic sensor system designed for demanding applications, like temperature measurements in the steel industry. The sensor system employed optical frequency domain reflectometry (OFDR) to interrogate Rayleigh backscattering signals in single-mode optical fibers. Temperature measurements employing the OFDR system were compared with conventional thermocouple measurements, accentuating the spatially distributed sensing capability of the fiber-optic system. Experiments were designed and conducted to test the spatial thermal mapping capability of the fiber-optic temperature measurement system. Experimental simulations provided evidence that the optical fiber system could resolve closely spaced temperature features, due to the high spatial resolution and fast measurement rates of the OFDR system. The ability of the fiber-optic system to perform temperature measurements in a metal casting was tested by monitoring aluminum solidification in a sand mold. The optical fiber, encased in a stainless steel tube, survived both mechanically and optically at temperatures exceeding 700 °C. The ability to distinguish between closely spaced temperature features that generate information-rich thermal maps opens up many applications in the steel industry.

Experimental Study of Leakage Monitoring of Diaphragm Walls Based on Distributed Optical Fiber Temperature Measurement Technology.

In geotechnical engineering seepage of diaphragm walls is an important issue which may cause engineering disasters. It is therefore of great significance to develop reliable monitoring technology to monitor the leakage. The purpose of this study is to explore the application of a distributed optical fiber temperature measurement system in leakage monitoring of underground diaphragm walls using 1 g model tests. The principles of seepage monitoring based on distributed optical fiber temperature measurement technology are introduced. Fiber with heating cable was laid along the wall to control seepage flow at different speeds. The temperature rise of the fiber during seepage was also recorded under different heating power conditions. In particular the effect of single variables (seepage velocity and heating power) on the temperature rise of optical fibers was discussed. Test results indicated that the temperature difference between the seepage and non-seepage parts of diaphragm wall can be monitored well using fiber-optic external heating cable. Higher heating power also can improve the resolution of fiber-optic seepage. The seepage velocity had a linear relationship with the final stable temperature after heating, and the linear correlation coefficient increases with the increase of heating power. The stable temperature decreased with the increase of flow velocity. The findings provide a basis for quantitative measurement and precise location of seepage velocity of diaphragm walls.

基于光纤测温技术的城市地表温度精细化分析

PDF HTML阅读 XML下载 导出引用 引用提醒 基于光纤测温技术的城市地表温度精细化分析 DOI: 10.5846/stxb201802060310 作者: 作者单位: 中国科学院生态环境研究中心 城市与区域生态国家重点实验室,中国科学院生态环境研究中心 城市与区域生态国家重点实验室,中国科学院生态环境研究中心 城市与区域生态国家重点实验室 作者简介: 通讯作者: 中图分类号: 基金项目: 国家重点研发计划资助（2016YFC0503605） Refined analysis of urban surface temperature based on optical fiber temperature measurement technology Author: Affiliation: State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Science, Chinese Academy of Sciences,State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Science, Chinese Academy of Sciences,State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Science, Chinese Academy of Sciences Fund Project: National Key Research And Development Plan(2016YFC0503605) 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:城市景观空间构型与热岛效应关联性较强，研究高时空分辨率的城市不同下垫面地表温度变化，可以更加精细地掌握城市热环境的时空特征。光纤温度传感系统具有实时在线、测温精度高和不受电磁干扰等优点，具备实时、在线、连续开展城市地表温度在线监测的能力。在北京市通州某园区内，选择有太阳辐射的4个时段，对多种类型下垫面的地表温度进行了时间间隔为1 min、空间间隔为1 m的连续4 h、总长度为100 m的实时在线监测。通过对监测时间段内不同类型下垫面地表温度的变化分析，发现这种分布式光纤测温系统能够有效辨识小尺度下地表温度的时间变化性和空间变化性，能有效区分透水和不透水地面，并监测和评估沥青马路地表温度的升温速率以及遮荫效果对地表温度的降温作用。同时，这种监测模式获取的数据能够对地表温度空间序列开展自相关分析，进一步验证了地表温度空间序列在较小尺度上仍然具有自相关性，且距离越近，相关性越大。研究同时表明，光纤测温技术能直接地获取城市热环境的现场真实数据，可以有效应用于小尺度城市热环境的观测与研究。 Abstract:The spatial configuration of the urban landscape is highly correlated with the heat island effect. By studying the land surface temperature (LST) of different underlying surfaces with high spatial and temporal resolution, we can grasp the temporal and spatial characteristics of the urban thermal environment more accurately. The optical fiber temperature sensing system has the advantages of real-time and high measurement accuracy and immunity to electromagnetic interference, and can monitor the LST in real time and continuously. In a park in Tongzhou, Beijing, four periods with solar radiation were selected, and the LST of various types of underlying surfaces was recorded in four consecutive hours with 1-minute time interval and 1-meter space interval, and the total length was 100 m. By analyzing the changes of LST of different underlying surface, it's proved that this distributed optical fiber temperature measurement system can effectively identify temporal and spatial variability of LST on a small scale, distinguish between permeable and impervious grounds, monitor the heating rate of the surface temperature of asphalt road, and evaluate the cooling effect of shading on LST. At the same time, data obtained by this monitoring mode enables autocorrelation analysis of LST spatial sequence. The results verified that the LST spatial sequence still has autocorrelation on a small scale, and the closer the distance, the higher the correlation level. Simultaneously, it is confirmed by this practice that the optical fiber temperature measurement technology can be effectively applied to the observation and research of small-scale urban thermal environment. 参考文献 相似文献 引证文献

Benchtop experiments of an ultrasound fiber optic temperature measurement system for atrial fibrillation ablation procedures

In this paper, we developed and tested an ultrasound fiber optic temperature measurement system for atrial fibrillation (Afib) ablation procedures. Currently, Afib ablation procedures lack an efficient way to provide a clinical end. To address this, we put forward a unique non-contact approach to measure the temperature on the ablated tissue. The temperature on the tissue is detected by measuring the acoustic velocity of the ultrasound signal, which is generated and detected by optical fibers. Benchtop experiments were performed on a bovine liver to validate the developed temperature measurement system. Experimental results indicated that the system had successfully registered the temperature changes on the surface of the bovine liver. The temperature measurement system can be further used to control the ablation dosage.

The Monitoring and Feedback for the Construction Quality of the Mass Concrete Based on the Distributed Optical-Fiber Temperature Measurement System

Temperature control is a key factor which affects the construction quality of the mass concrete, which is also an important measure to prevent crack propagation. Lots of engineering practices show that most of temperature cracks come out in the form of the surface crack during the construction of the concrete dam. In addition, deep cracks and transverse cracks are usually developed by surface cracks. Strengthening conversation and surface insulation are one of the main methods to prevent surface cracks. In this paper, Xiluodu hydropower dam is taken as the engineering background, and an insulation monitoring experiment under the winter low-temperature condition was carried out on the fresh concrete layer during the construction period using the distributed fiber optic temperature monitoring system. The inversion of the equivalent heat coefficient for the fresh concrete layer with the covering of the polyethylene membrane insulation materials was conducted, besides the monitoring results and the feedback analysis of the conservation status was obtained based on the test data. The above procedure provides a basis for evaluating the quality of construction and the dynamic adjustment of the construction programs.

分布式喇曼光纤测温系统中修正测量误差的方法

分布式喇曼光纤测温系统中修正测量误差的方法

Application Situation of Distributed Optical Fiber Temperature Measurement Technology in Power System

Temperature is an important operating parameter of electrical equipment, electrical equipment operating condition obtained by monitoring the temperature information has become research focus for power system fault prediction and diagnosis[1-. Distributed fiber optic temperature measurement system is a method for real-time measurement of the spatial distribution of temperature field sensing system. The system uses optical time domain reflectometer (OTDR) and laser Raman spectroscopy, amplifies temperature information and processes signal from wavelength division multiplexer and optical detectors, then the temperature information is displayed in real time[4-. Distributed fiber optic temperature measurement technology has several characteristics with insulation, anti-electromagnetic interference, resistance to high voltage, resistance to chemical corrosion, and security[6-. This article outlines the basic power system temperature monitoring content, studies the current distributed optical fiber temperature measurement technology applications in power system and prospects for its development trend.

Inner wall running state monitoring for the main pipe of nuclear power

The heat conduction equation is solved in this paper under specific boundary conditions. The coefficients of the obtained distribution equation are simplified with the piecewise integral method. Then the associated model for the cylindrical thermal equipment is established. The relationship of the surface temperatures, the material properties and the inner wall state of the cylindrical thermal equipment is described in the associated model. This model is applied to the inner wall running state monitoring of the main pipe. A multi-channel distributed optical fiber temperature measurement system is designed to acquire the external surface temperatures of the main pipe. Then the associated model can be used to analyze the surface temperature data of the main pipe. The location and the physical dimension of the inner wall defect can be got. Therefore, the inner wall defect monitoring of the main pipe can be realized. The feasibility of this method is verified by experiment. This method also provides a theoretical basis for the real-time monitoring of the main pipe’s internal state.

On-line Temperature Measurement System for Carbonization Chamber Wall of Coke Oven

The basic principle of radiation pyrometer and colorimetric pyrometer are introduced first. Then the design of a colorimetric fiber-optic temperature measurement system used for temperature measurement in the carbonization chamber of coke oven is described in detail. The use of double-clad silica fiber solves the problem of high ambient temperature. The system is consisted by STC12C5A60S2 single-chip microcomputer as the core and AD converter MAX195. The colorimetric temperature measurement can eliminate the background interference and the measuring precision and stability are greatly enhanced. Temperature measurement system is satisfied with the demand of scene. It is shown that this system is available.

Applications of Y2O2S: Eu+Fe2O3 Materials in Fluorescence Fiber System

A set of fluorescence optical fiber temperature measurement system is designed based on Y2O2S:Eu+Fe2O3.The system is mainly composed of the following parts: excitated illuminant, probe, photoelectric detector, belt wave filter, zero checking and fluorescence life-span measurement device. The fluorescence matters give out light when they are stimulated by external light. Fluorescence intensity and life-span depend on the fluorophore temperature. Fluorescence life-span is fluorescence materials’ inherence characteristic, we can realize temperature's absolut measurement by carrying out this measurement, and it has very good sensitiveness and measure accuracy within the low and middle temperature range. Fluorescence frequency is identical with exciting light since exciting light is modulated to a fixed frequency. Y2O2S:Eu+Fe2O3is a new material handled by Y2O2S:Eu with red pigment of ferric oxide, while the corresponding wave crest’s intensity of Y2O2S:Eu+Fe2O3is 9 times higher than Y2O2S:Eu nearly a magnitude. The experiment of the optical spectrum to several sensitive materials confirms the match that Y2O2S:Eu+Fe2O3is with light source and the feasibility of the system.

Low-Cost Fiber-Optic Temperature Measurement System for High-Voltage Electrical Power Equipment

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> To precisely measure temperature in high-voltage electrical power equipment subject to intense electromagnetic interference (EMI), we present an artificial neural network (ANN) inverse compensating method, based on which we also construct a compounded fiber-optic temperature measurement system (CFOTMS). The CFOTMS consists of a fiber-optic semiconductor absorption temperature sensor (FOSATS) and an ANN inverse compensator. On one hand, optical-fiber-based light transmission is insusceptible to EMI; on the other hand, due to the utilization of the ANN inverse compensator, the dynamic performance and measuring precision of the CFOTMS are significantly enhanced compared with the sole use of the sensor. Therefore, it is very suitable to be used in high-voltage electrical power equipment. Furthermore, as the intensity-dependent FOSATS is a cheap device, and the ANN inverse compensator is realized in software, the cost of the CFOTMS will be low, which makes it suitable to be used in economical equipment. </para>

Characterization of Spatial Non-Uniformity in Microwave Reheating of High Loss Foods

In order to characterize the non-uniformity of microwave heating when power deposition can be approximated as simple exponential decay, a correlation was developed between temperature non-uniformity and the significant parameters, such as surface microwave flux, penetration depth and the duration of heating. An index of temperature non-uniformity was developed as the difference between the average temperatures of the hottest 5% of the volume and the coldest 5% of the volume. Temperatures calculated using a numerical solution to the energy equation were used to develop the correlation. Experimental verifications were carried out using both a fiberoptic temperature measurement system and an infrared thermal imaging system. Results are provided in terms of a simple expression that can be used to estimate the expected non-uniformity of heating in product and process development, by knowing the dielectric and the thermal properties of a food material.