Detection of Small Leaks in Liquid Pipelines Utilizing Distributed Temperature Sensing

2012 ◽  
Author(s):  
Shane P. Siebenaler ◽  
Gary R. Walter
Keyword(s):  
Near Field ◽  
Temperature Response ◽  
Temperature Sensing ◽  
Transient Temperature ◽  
False Alarms ◽  
Distributed Temperature Sensing ◽  
Sensitivity Testing ◽  
Alarm Systems ◽  
Integrity Management ◽  
The Impact

Leaks from hazardous liquid pipelines can have significant impacts on safety and the environment. The detection of such leaks in their infancy is important to the overall integrity management of pipelines. The traditional means of detecting leaks on this infrastructure typically involve visual inspection or computational monitoring. However, such methods are often inadequate for detecting and locating small discharges that can result in damage to the environment. One potential alternative technology is distributed temperature sensing (DTS). The analytical work in this paper details near-field thermal effects surrounding the pipeline, seasonal and diurnal impacts on temperature as a function of buried depth, and the impact of transient temperature response from batch product operations. The analysis demonstrated that DTS employed on a buried transmission line would be immune from many of these effects and would not generate numerous false alarms due to these conditions. Laboratory testing was conducted on both Brillouin and Raman-based DTS systems; a total of four different manufacturer’s products were utilized. The testing characterized any limitations of such systems as a function of wetted length. The testing demonstrated that such technology could accurately detect small temperature fluctuations over distances exceeding 12 km (7.5 mi) to a location with a resolution of one meter. In addition to sensitivity testing of the systems, the automated alarm systems were tested to ensure that the systems could detect leaks without generating numerous false alarms.

scholarly journals Determining the Relation between Groundwater Flow Velocities and Measured Temperature Differences Using Active Heating-Distributed Temperature Sensing

Water ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1619 ◽  
Author(s):  
Bakx ◽  
Doornenbal ◽  
Weesep ◽  
Bense ◽  
Essink ◽  
...  
Keyword(s):  
Groundwater Flow ◽  
Flow Velocity ◽  
Temperature Response ◽  
Flow Equation ◽  
Absolute Temperature ◽  
Temperature Sensing ◽  
Measured Temperature ◽  
Distributed Temperature Sensing ◽  
Plan View ◽  
Flow Velocities

Active Heating-Distributed Temperature Sensing (AH-DTS) has the potential to allow for the measurement of groundwater flow velocities in situ. We placed DTS fiber-optic cables combined with a heating wire in direct contact with aquifer sediments in a laboratory scale groundwater flow simulator. Using this setup, we empirically determined the relationship between ΔT, the temperature difference by constant and uniform heating of the DTS cable and the background temperature of the groundwater system, and horizontal groundwater flow velocity. Second, we simulated the observed temperature response of the system using a plan-view heat transfer flow model to calibrate for the thermal properties of the sediment and to optimize cable setup for sensitivity to variation in groundwater flow velocities. Additionally, we derived an analytical solution based on the heat flow equation that can be used to explicitly calculate flow velocity from measured ΔT for this specific AH-DTS cable setup. We expect that this equation, after calibration for cable constitution, is valid for estimating groundwater flow velocity based on absolute temperature differences measured in field applications using this cable setup.

High-Efficiency Transient Temperature Calculations for Applications in Dynamic Thermal Management of Electronic Devices

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
Maxat N. Touzelbaev ◽  
Josef Miler ◽  
Yizhang Yang ◽  
Gamal Refai-Ahmed ◽  
Kenneth E. Goodson
Keyword(s):  
Thermal Management ◽  
Impulse Response ◽  
Semiconductor Devices ◽  
Temperature Response ◽  
Infinite Impulse Response ◽  
Transient Temperature ◽  
Modeling Tools ◽  
Dynamic Thermal Management ◽  
The Impact ◽  
Power Densities

The highly nonuniform transient power densities in modern semiconductor devices present difficult performance and reliability challenges for circuit components, multiple levels of interconnections and packaging, and adversely impact overall power efficiencies. Runtime temperature calculations would be beneficial to architectures with dynamic thermal management, which control hotspots by effectively optimizing regional power densities. Unfortunately, existing algorithms remain computationally prohibitive for integration within such systems. This work addresses these shortcomings by formulating an efficient method for fast calculations of temperature response in semiconductor devices under a time-dependent dissipation power. A device temperature is represented as output of an infinite-impulse response (IIR) multistage digital filter, processing a stream of sampled power data; this method effectively calculates temperatures by a fast numerical convolution of the sampled power with the modeled system's impulse response. Parameters such as a steady-state thermal resistance or its extension to a transient regime, a thermal transfer function, are typically used with the assumption of a linearity and time-invariance (LTI) to form a basis for device thermal characterization. These modeling tools and the time-discretized estimates of dissipated power make digital filtering a well-suited technique for a run-time temperature calculation. A recursive property of the proposed algorithm allows a highly efficient use of an available computational resource; also, the impact of all of the input power trace is retained when calculating a temperature trace. A network identification by deconvolution (NID) method is used to extract a time-constant spectrum of the device temperature response. We verify this network extraction procedure for a simple geometry with a closed-form solution. In the proposed technique, the amount of microprocessor clock cycles needed for each temperature evaluation remains fixed, which results in a linear relationship between the overall computation time and the number of temperature evaluations. This is in contrast to time-domain convolution, where the number of clock cycles needed for each evaluation increases as the time window expands. The linear dependence is similar to techniques based on FFT algorithms; in this work, however, use of z-transforms significantly decreases the amount of computations needed per temperature evaluation, in addition to much reduced memory requirements. Together, these two features result in vast improvements in computational throughput and allow implementations of sophisticated runtime dynamic thermal management algorithms for all high-power architectures and expand the application range to embedded platforms for use in a pervasive computing environment.

scholarly journals A distributed heat pulse sensor network for thermo-hydraulic monitoring of the soil subsurface

2020 ◽  
Vol 53 (3) ◽  
pp. 352-365 ◽  
Author(s):  
Corinna Abesser ◽  
Francesco Ciocca ◽  
John Findlay ◽  
David Hannah ◽  
Philip Blaen ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Temporal Dynamics ◽  
Temperature Response ◽  
Soil Disturbance ◽  
Temperature Sensing ◽  
Soil Parameters ◽  
Spatial And Temporal Variability ◽  
Fibre Optic ◽  
Distributed Temperature Sensing ◽  
Content Type

Fibre optic distributed temperature sensing (DTS) is used increasingly for environmental monitoring and subsurface characterization. Combined with heating of metal elements embedded within the fibre optic cable, the temperature response of the soil provides valuable information from which soil parameters such as thermal conductivity and soil moisture can be derived at high spatial and temporal resolution, and over long distances.We present a novel active distributed temperature sensing (A-DTS) system and its application to characterize spatial and temporal dynamics in soil thermal conductivity along a recently forested hillslope in Central England, UK. Compared with conventional techniques (needle probe surveys), A-DTS provided values with a similar spread although lower on average. The larger number of measurement points that A-DTS provides at higher spatial and temporal resolutions and the ability to repeat surveys under different meteorological or hydrological conditions allow for a more detailed examination of the spatial and temporal variability of thermal conductivities at the study site. Although system deployment time and costs are higher than with needle probes, A-DTS can be extremely appealing for applications requiring long-term monitoring, at high temporal repeatability, over long (kilometres) distances and with minimum soil disturbance, compared with one-off spatial surveys.Thematic collection: This article is part of the Measurement and monitoring collection available at: https://www.lyellcollection.org/cc/measurement-and-monitoring

scholarly journals Limitations of fibre optic distributed temperature sensing for quantifying surface water groundwater interactions

2014 ◽  
Vol 11 (7) ◽  
pp. 8167-8190 ◽  
Author(s):  
H. Roshan ◽  
M. Young ◽  
M. S. Andersen ◽  
R. I. Acworth
Keyword(s):  
Surface Water ◽  
Temperature Difference ◽  
Groundwater Discharge ◽  
Water Injection ◽  
Temperature Response ◽  
Temperature Sensing ◽  
Hot Water ◽  
Apparent Temperature ◽  
Distributed Temperature Sensing ◽  
Simulated Surface

Abstract. Studies of surface water–groundwater interactions using fiber optic distributed temperature sensing (FO-DTS) has increased in recent years. However, only a few studies to date have explored the limitations of FO-DTS in detecting groundwater discharge to streams. A FO_DTS system was therefore tested in a flume under controlled laboratory conditions for its ability to accurately measure the discharge of hot or cold groundwater into a simulated surface water flow. In the experiment the surface water (SW) and groundwater (GW) velocities, expressed as ratios (vgw/vsw), were varied from 0.21% to 61.7%; temperature difference between SW-GW were varied from 2 to 10 °C; the direction of temperature gradient were varied with both cold and-hot water injection; and two different bed materials were used to investigate their effects on FO_DTS's detection limit of groundwater discharge. The ability of the FO_DTS system to detect the discharge of groundwater of a different temperature in the laboratory environment was found to be mainly dependent upon the surface and groundwater flow velocities and their temperature difference. A correlation was proposed to estimate the groundwater discharge from temperature. The correlation is valid when the ratio of the apparent temperature response to the source temperature difference is above 0.02.

Probabilistic Estimates of Transient Climate Sensitivity Subject to Uncertainty in Forcing and Natural Variability

2011 ◽  
Vol 24 (21) ◽  
pp. 5521-5537 ◽  
Author(s):  
Lauren E. Padilla ◽  
Geoffrey K. Vallis ◽  
Clarence W. Rowley
Keyword(s):  
Surface Temperature ◽  
Climate Sensitivity ◽  
General Circulation ◽  
Temperature Response ◽  
Circulation Model ◽  
Ocean General Circulation Model ◽  
Balance Model ◽  
Transient Temperature ◽  
Model Parameters ◽  
The Impact

Abstract In this paper, the authors address the impact of uncertainty on estimates of transient climate sensitivity (TCS) of the globally averaged surface temperature, including both uncertainty in past forcing and internal variability in the climate record. This study provides a range of probabilistic estimates of the TCS that combine these two sources of uncertainty for various underlying assumptions about the nature of the uncertainty. The authors also provide estimates of how quickly the uncertainty in the TCS may be expected to diminish in the future as additional observations become available. These estimates are made using a nonlinear Kalman filter coupled to a stochastic, global energy balance model, using the filter and observations to constrain the model parameters. This study verifies that model and filter are able to emulate the evolution of a comprehensive, state-of-the-art atmosphere–ocean general circulation model and to accurately predict the TCS of the model, and then apply the methodology to observed temperature and forcing records of the twentieth century. For uncertainty assumptions best supported by global surface temperature data up to the present time, this paper finds a most likely present-day estimate of the transient climate sensitivity to be 1.6 K, with 90% confidence the response will fall between 1.3 and 2.6 K, and it is estimated that this interval may be 45% smaller by the year 2030. The authors calculate that emissions levels equivalent to forcing of less than 475 ppmv CO2 concentration are needed to ensure that the transient temperature response will not exceed 2 K with 95% confidence. This is an assessment for the short-to-medium term and not a recommendation for long-term stabilization forcing; the equilibrium temperature response to this level of CO2 may be much greater. The flat temperature trend of the last decade has a detectable but small influence on TCS. This study describes how the results vary if different uncertainty assumptions are made and shows they are robust to variations in the initial prior probability assumptions.

High-spatial-resolution Distributed Temperature Sensing System Based on a Mode-locked Fiber Laser

2020 ◽  
Author(s):  
Anton O. Chernutsky ◽  
Dmitriy A. Dvoretskiy ◽  
Ilya O. Orekhov ◽  
Stanislav G. Sazonkin ◽  
Yan Zh. Ososkov ◽  
...  
Keyword(s):  
Fiber Laser ◽  
Spatial Resolution ◽  
High Spatial Resolution ◽  
Temperature Sensing ◽  
Distributed Temperature Sensing ◽  
Sensing System
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