The Experts below are selected from a list of 327 Experts worldwide ranked by ideXlab platform
Tom E. Diller - One of the best experts on this subject based on the ideXlab platform.
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Direct Measurement of Hot-Wall Heat Flux
Journal of Thermophysics and Heat Transfer, 2012Co-Authors: Clayton A. Pullins, Tom E. DillerAbstract:The implementation and use of high-temperature-capable Heat Flux Sensors is investigated in several different hotwall measurement scenarios. A graphite flat-plate Heater was used to generate high Heat Fluxes representative of hypersonic flight. This allowed the comparison of cold-wall and hot-wall Heat Flux measurements under carefully controlled experimental conditions by using a high-temperature Heat Flux Sensor mounted on three very different substrates, from an actively cooled body to a well-insulated body.Awater-cooled Gardon Heat Flux Sensor was used to measure the incident radiation in all cases. Incident radiation Heat Fluxes as high as 65 W · cm -2 and hightemperature Heat Flux Sensor surface temperatures as high as 1130°C were realized. A unique data-processing scheme rendered the high-temperature Heat Flux Sensor virtually insensitive to the material on which it is mounted and accounted for the Sensor's temperature-dependent properties. Because of the emitted radiation and natural convection from the high-temperature Heat Flux Sensor surface, the net Heat Flux was very different from the incident Heat Flux measured by the cold Sensor (water-cooled Gardon). For these idealized cases, the incident radiation could be predicted from the hot-wall total Heat Flux measurements. For more realistic conditions, however, it is important to be able to measure the actual Heat Flux desired. Copyright © 2012 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
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Adaptation of the in-cavity calibration method for high temperature Heat Flux Sensors
International Journal of Heat and Mass Transfer, 2011Co-Authors: Clayton A. Pullins, Tom E. DillerAbstract:Abstract The need for in situ Heat Flux measurements in hot structures, used in hypersonic vehicle thermal protection system development, combustion and propulsion research, and fire testing requires that Heat Flux Sensors are characterized over their entire operating temperature range. The in-cavity Heat Flux Sensor calibration technique has been adapted to accommodate elevated Sensor temperatures, in an effort to develop a primary calibration scheme for high temperature Heat Flux Sensors using an existing blackbody calibration system. The new scheme has been demonstrated through the calibration of a high temperature, thermopile-type Heat Flux Sensor. The output temperature dependence of the high temperature Heat Flux Sensor (HTHFS) has been successfully characterized over the range of 175–960 °C with acceptable uncertainty limits. The calibrated HTHFS sensitivity agrees well with a theoretical sensitivity model, suggesting that the extended in-cavity calibration technique is a viable choice for primary calibration of Heat Flux Sensors at elevated Sensor temperatures.
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Adaptation of the in-cavity calibration method for high temperature Heat Flux Sensors
International Journal of Heat and Mass Transfer, 2011Co-Authors: Clayton A. Pullins, Tom E. DillerAbstract:The need for in situ Heat Flux measurements in hot structures, used in hypersonic vehicle thermal protection system development, combustion and propulsion research, and fire testing requires that Heat Flux Sensors are characterized over their entire operating temperature range. The in-cavity Heat Flux Sensor calibration technique has been adapted to accommodate elevated Sensor temperatures, in an effort to develop a primary calibration scheme for high temperature Heat Flux Sensors using an existing blackbody calibration system. The new scheme has been demonstrated through the calibration of a high temperature, thermopile-type Heat Flux Sensor. The output temperature dependence of the high temperature Heat Flux Sensor (HTHFS) has been successfully characterized over the range of 175-960 °C with acceptable uncertainty limits. The calibrated HTHFS sensitivity agrees well with a theoretical sensitivity model, suggesting that the extended in-cavity calibration technique is a viable choice for primary calibration of Heat Flux Sensors at elevated Sensor temperatures. © 2010 Elsevier Ltd. All rights reserved.
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in situ high temperature Heat Flux Sensor calibration
International Journal of Heat and Mass Transfer, 2010Co-Authors: Clayton A. Pullins, Tom E. DillerAbstract:Abstract Recent advances in Heat Flux measurement have resulted in the development of a robust thermopile Heat Flux Sensor intended for use in extreme thermal environments. The High Temperature Heat Flux Sensor (HTHFS) is capable of simultaneously measuring thermopile surface temperature and Heat Flux at Sensor temperatures up to 1000 °C. The need for high temperature Heat Flux calibration of the HTHFS has resulted in the development of a new wide angle radiation calibration system, which operates with the Sensor at elevated temperatures. The temperature dependence of the Sensor output over the range of 100–900 °C has been successfully characterized with acceptable uncertainty limits. The calibrated HTHFS sensitivity agrees well with a theoretical sensitivity model, suggesting that the primary cause for the Sensor’s output temperature dependence is due to the change in thermal conductivity of the Sensor elements with temperature.
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In situ high temperature Heat Flux Sensor calibration
International Journal of Heat and Mass Transfer, 2010Co-Authors: Clayton A. Pullins, Tom E. DillerAbstract:Recent advances in Heat Flux measurement have resulted in the development of a robust thermopile Heat Flux Sensor intended for use in extreme thermal environments. The High Temperature Heat Flux Sensor (HTHFS) is capable of simultaneously measuring thermopile surface temperature and Heat Flux at Sensor temperatures up to 1000 °C. The need for high temperature Heat Flux calibration of the HTHFS has resulted in the development of a new wide angle radiation calibration system, which operates with the Sensor at elevated temperatures. The temperature dependence of the Sensor output over the range of 100-900 °C has been successfully characterized with acceptable uncertainty limits. The calibrated HTHFS sensitivity agrees well with a theoretical sensitivity model, suggesting that the primary cause for the Sensor's output temperature dependence is due to the change in thermal conductivity of the Sensor elements with temperature. © 2010 Elsevier Ltd. All rights reserved.
Clayton A. Pullins - One of the best experts on this subject based on the ideXlab platform.
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Direct Measurement of Hot-Wall Heat Flux
Journal of Thermophysics and Heat Transfer, 2012Co-Authors: Clayton A. Pullins, Tom E. DillerAbstract:The implementation and use of high-temperature-capable Heat Flux Sensors is investigated in several different hotwall measurement scenarios. A graphite flat-plate Heater was used to generate high Heat Fluxes representative of hypersonic flight. This allowed the comparison of cold-wall and hot-wall Heat Flux measurements under carefully controlled experimental conditions by using a high-temperature Heat Flux Sensor mounted on three very different substrates, from an actively cooled body to a well-insulated body.Awater-cooled Gardon Heat Flux Sensor was used to measure the incident radiation in all cases. Incident radiation Heat Fluxes as high as 65 W · cm -2 and hightemperature Heat Flux Sensor surface temperatures as high as 1130°C were realized. A unique data-processing scheme rendered the high-temperature Heat Flux Sensor virtually insensitive to the material on which it is mounted and accounted for the Sensor's temperature-dependent properties. Because of the emitted radiation and natural convection from the high-temperature Heat Flux Sensor surface, the net Heat Flux was very different from the incident Heat Flux measured by the cold Sensor (water-cooled Gardon). For these idealized cases, the incident radiation could be predicted from the hot-wall total Heat Flux measurements. For more realistic conditions, however, it is important to be able to measure the actual Heat Flux desired. Copyright © 2012 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
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Adaptation of the in-cavity calibration method for high temperature Heat Flux Sensors
International Journal of Heat and Mass Transfer, 2011Co-Authors: Clayton A. Pullins, Tom E. DillerAbstract:Abstract The need for in situ Heat Flux measurements in hot structures, used in hypersonic vehicle thermal protection system development, combustion and propulsion research, and fire testing requires that Heat Flux Sensors are characterized over their entire operating temperature range. The in-cavity Heat Flux Sensor calibration technique has been adapted to accommodate elevated Sensor temperatures, in an effort to develop a primary calibration scheme for high temperature Heat Flux Sensors using an existing blackbody calibration system. The new scheme has been demonstrated through the calibration of a high temperature, thermopile-type Heat Flux Sensor. The output temperature dependence of the high temperature Heat Flux Sensor (HTHFS) has been successfully characterized over the range of 175–960 °C with acceptable uncertainty limits. The calibrated HTHFS sensitivity agrees well with a theoretical sensitivity model, suggesting that the extended in-cavity calibration technique is a viable choice for primary calibration of Heat Flux Sensors at elevated Sensor temperatures.
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Adaptation of the in-cavity calibration method for high temperature Heat Flux Sensors
International Journal of Heat and Mass Transfer, 2011Co-Authors: Clayton A. Pullins, Tom E. DillerAbstract:The need for in situ Heat Flux measurements in hot structures, used in hypersonic vehicle thermal protection system development, combustion and propulsion research, and fire testing requires that Heat Flux Sensors are characterized over their entire operating temperature range. The in-cavity Heat Flux Sensor calibration technique has been adapted to accommodate elevated Sensor temperatures, in an effort to develop a primary calibration scheme for high temperature Heat Flux Sensors using an existing blackbody calibration system. The new scheme has been demonstrated through the calibration of a high temperature, thermopile-type Heat Flux Sensor. The output temperature dependence of the high temperature Heat Flux Sensor (HTHFS) has been successfully characterized over the range of 175-960 °C with acceptable uncertainty limits. The calibrated HTHFS sensitivity agrees well with a theoretical sensitivity model, suggesting that the extended in-cavity calibration technique is a viable choice for primary calibration of Heat Flux Sensors at elevated Sensor temperatures. © 2010 Elsevier Ltd. All rights reserved.
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in situ high temperature Heat Flux Sensor calibration
International Journal of Heat and Mass Transfer, 2010Co-Authors: Clayton A. Pullins, Tom E. DillerAbstract:Abstract Recent advances in Heat Flux measurement have resulted in the development of a robust thermopile Heat Flux Sensor intended for use in extreme thermal environments. The High Temperature Heat Flux Sensor (HTHFS) is capable of simultaneously measuring thermopile surface temperature and Heat Flux at Sensor temperatures up to 1000 °C. The need for high temperature Heat Flux calibration of the HTHFS has resulted in the development of a new wide angle radiation calibration system, which operates with the Sensor at elevated temperatures. The temperature dependence of the Sensor output over the range of 100–900 °C has been successfully characterized with acceptable uncertainty limits. The calibrated HTHFS sensitivity agrees well with a theoretical sensitivity model, suggesting that the primary cause for the Sensor’s output temperature dependence is due to the change in thermal conductivity of the Sensor elements with temperature.
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In situ high temperature Heat Flux Sensor calibration
International Journal of Heat and Mass Transfer, 2010Co-Authors: Clayton A. Pullins, Tom E. DillerAbstract:Recent advances in Heat Flux measurement have resulted in the development of a robust thermopile Heat Flux Sensor intended for use in extreme thermal environments. The High Temperature Heat Flux Sensor (HTHFS) is capable of simultaneously measuring thermopile surface temperature and Heat Flux at Sensor temperatures up to 1000 °C. The need for high temperature Heat Flux calibration of the HTHFS has resulted in the development of a new wide angle radiation calibration system, which operates with the Sensor at elevated temperatures. The temperature dependence of the Sensor output over the range of 100-900 °C has been successfully characterized with acceptable uncertainty limits. The calibrated HTHFS sensitivity agrees well with a theoretical sensitivity model, suggesting that the primary cause for the Sensor's output temperature dependence is due to the change in thermal conductivity of the Sensor elements with temperature. © 2010 Elsevier Ltd. All rights reserved.
Vladimir Y Mityakov - One of the best experts on this subject based on the ideXlab platform.
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condition monitoring of wind power converters using Heat Flux Sensor
International Review of Electrical Engineering-iree, 2016Co-Authors: E Baygildina, A V Mityakov, Raimo Juntunen, Kirill Murashko, Markku Kuisma, L. Smirnova, Pasi Peltoniemi, Olli Pyrhönen, Kullervo Hynynen, Vladimir Y MityakovAbstract:The application of the gradient Heat Flux Sensor as a failure and aging indicator of the power electronics was studied in this paper. Conducted experiments shown that the Heat Flux Sensor attached to the insulated-gate bipolar transistor’s (IGBT’s) base plate can provide real-time Heat Flux monitoring. Condition monitoring (CM) model implemented in wind turbine based on online comparison of measured IGBT Heat Flux and expected power losses was proposed. The deviation of the measured Heat Flux from the expected power losses was detected during IGBT’s package related failures. The maximum deviation of 30% was obtained from the module with broken bond wire. The IGBT's package related degradation mechanisms were modeled by the Finite Element Method (FEM) in order to validate experimental observations. The obtained results have shown that in order to accurately estimate the possible deviation of power losses of the degraded IGBT, the exact change in thermo-electric parameters of IGBT in different failure mechanisms, environmental conditions and operating temperatures should be taken into account.
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application of a Heat Flux Sensor in wind power electronics
Energies, 2016Co-Authors: E Baygildina, A V Mityakov, Raimo Juntunen, Kirill Murashko, Markku Kuisma, L. Smirnova, Pasi Peltoniemi, Olli Pyrhönen, Kullervo Hynynen, Vladimir Y MityakovAbstract:This paper proposes and investigates the application of the gradient Heat Flux Sensor (GHFS) for measuring the local Heat Flux in power electronics. Thanks to its thinness, the Sensor can be placed between the semiconductor module and the Heat sink. The GHFS has high sensitivity and yields direct measurements without an interruption to the normal power device operation, which makes it attractive for power electronics applications. The development of systems for monitoring thermal loading and methods for online detection of degradation and failure of power electronic devices is a topical and crucial task. However, online condition monitoring (CM) methods, which include Heat Flux Sensors, have received little research attention so far. In the current research, an insulated-gate bipolar transistor (IGBT) module-based test setup with the GHFS implemented on the base plate of one of the IGBTs is introduced. The Heat Flux experiments and the IGBT power losses obtained by simulations show similar results. The findings give clear evidence that the GHFS can provide an attractive condition monitoring method for the thermal loading of power devices.
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Condition monitoring of wind power converters using Heat Flux Sensor
International Review of Electrical Engineering, 2016Co-Authors: E Baygildina, A V Mityakov, Raimo Juntunen, Kirill Murashko, Markku Kuisma, L. Smirnova, Pasi Peltoniemi, Olli Pyrhönen, Kullervo Hynynen, Vladimir Y MityakovAbstract:The application of the gradient Heat Flux Sensor as a failure and aging indicator of the power electronics was studied in this paper. Conducted experiments shown that the Heat Flux Sensor attached to the insulated-gate bipolar transistor’s (IGBT’s) base plate can provide realtime Heat Flux monitoring. Condition monitoring (CM) model implemented in wind turbine based on online comparison of measured IGBT Heat Flux and expected power losses was proposed. The deviation of the measured Heat Flux from the expected power losses was detected during IGBT’s package related failures. The maximum deviation of 30% was obtained from the module with broken bond wire. The IGBT’s package related degradation mechanisms were modeled by the Finite Element Method (FEM) in order to validate experimental observations. The obtained results have shown that in order to accurately estimate the possible deviation of power losses of the degraded IGBT, the exact change in thermo-electric parameters of IGBT in different failure mechanisms, environmental conditions and operating temperatures should be taken into account. © 2016 Praise Worthy Prize S.r.l. - All rights reserved.
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Application of the gradient Heat Flux Sensor to study pulsed processes in a shock tube
Technical Physics, 2008Co-Authors: S V Bobashev, Yu.p. Golovachov, N P Mende, B I Reznikov, V A Sakharov, A S Chernyshev, P. A. Popov, A. A. Schmidt, Sergey Z Sapozhnikov, Vladimir Y MityakovAbstract:The surface temperature of a model body of revolution placed in a pulsed supersonic nitrogen flow is measured with the help of a gradient Heat Flux Sensor. From the measured temperature, a Heat Flux toward the surface of the body is determined. The steady flow of a viscous transcalent gas about the body is numerically calculated. The results of the numerical calculation and measuring data are in good agreement. © 2008 Pleiades Publishing, Ltd.
Vladimir Szekely - One of the best experts on this subject based on the ideXlab platform.
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Heat Flux Sensor to support transient thermal characterisation of ic packages
Sensors and Actuators A-physical, 2004Co-Authors: Marta Rencz, Elizabeth Kollar, Vladimir SzekelyAbstract:In this paper the idea and the analysis of a microelectronic Heat-Flux Sensor, designed for fast transient measurements in package characterisation is presented. The Sensor was fabricated in a prototype version, and the measured results prove the validity of the design concepts. The sensitivity, temperature dependence and resolution values are calculated and evaluated. The questions of calibration are discussed. Three application examples are presented. In the first two it is demonstrated, how the Sensor may support compact model generation of packages by measuring the time dependence of the Heat Flux leaving the package on a certain surface, and by enabling the direct measurement of the thermal transfer admittance parameters of packages. In the third example the Sensor is realised in array form, providing the possibility to obtain the coarse Heat Flux map of a package surface.
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Heat-Flux Sensor to support transient thermal characterisation of IC packages
Sensors and Actuators A: Physical, 2004Co-Authors: Marta Rencz, Elizabeth Kollar, Vladimir SzekelyAbstract:In this paper the idea and the analysis of a microelectronic Heat-Flux Sensor, designed for fast transient measurements in package characterisation is presented. The Sensor was fabricated in a prototype version, and the measured results prove the validity of the design concepts. The sensitivity, temperature dependence and resolution values are calculated and evaluated. The questions of calibration are discussed. Three application examples are presented. In the first two it is demonstrated, how the Sensor may support compact model generation of packages by measuring the time dependence of the Heat Flux leaving the package on a certain surface, and by enabling the direct measurement of the thermal transfer admittance parameters of packages. In the third example the Sensor is realised in array form, providing the possibility to obtain the coarse Heat Flux map of a package surface. © 2004 Elsevier B.V. All rights reserved.
S.h. Oh - One of the best experts on this subject based on the ideXlab platform.
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bulk micromachined circular foil type micro Heat Flux Sensor
Sensors and Actuators A-physical, 2006Co-Authors: S.h. Oh, J. C. JeonAbstract:Abstract A micro Heat-Flux Sensor with high sensitivity under conditions of low Heat Flux has been designed, bulk-micromachined and tested in a convective environment. The Sensor, which is based on the circular foil type Heat-Flux Sensor, is composed of thermal paths and a thermopile. Thermal path layers of electroplated copper on both sides of a wafer are connected through a bulk-micromachined window. A thermopile consisting of a series of n thermocouples is used to get an n -fold output compared to a single couple. When the Sensor is placed on a high temperature wall, Heat Flux from the wall flows through thermal paths and drains out to the environment, producing a temperature difference along these paths. The Heat Flux is obtained by measuring the temperature difference using a thermopile of Ni–Cr thermocouples. The calibrated sensitivity of the micro Heat-Flux Sensor is 0.17–1.90 μV/(mW cm −2 ) in the Heat Flux range 0–180 mW/cm 2 .
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Bulk-micromachined circular foil type micro Heat-Flux Sensor
Sensors and Actuators A: Physical, 2006Co-Authors: S.h. Oh, J. C. Jeon, Sung-hee Lee, Myung-hyun Kim, S.-s. LeeAbstract:A micro Heat-Flux Sensor with high sensitivity under conditions of low Heat Flux has been designed, bulk-micromachined and tested in a convective environment. The Sensor, which is based on the circular foil type Heat-Flux Sensor, is composed of thermal paths and a thermopile. Thermal path layers of electroplated copper on both sides of a wafer are connected through a bulk-micromachined window. A thermopile consisting of a series of n thermocouples is used to get an n-fold output compared to a single couple. When the Sensor is placed on a high temperature wall, Heat Flux from the wall flows through thermal paths and drains out to the environment, producing a temperature difference along these paths. The Heat Flux is obtained by measuring the temperature difference using a thermopile of Ni-Cr thermocouples. The calibrated sensitivity of the micro Heat-Flux Sensor is 0.17-1.90 μV/(mW cm-2) in the Heat Flux range 0-180 mW/cm2. © 2005 Elsevier B.V. All rights reserved.
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IROS - Design and fabrication of micro Heat Flux Sensor
Proceedings 1999 IEEE RSJ International Conference on Intelligent Robots and Systems. Human and Environment Friendly Robots with High Intelligence and, 1999Co-Authors: Jaechul Chun, S.h. OhAbstract:A novel micro Heat Flux Sensor which can measure small Heat Flux has been designed, fabricated, and tested in a convective environment. The micro Heat Flux Sensor receives the Heat Flux from the wall through the contact gold film, then the received Heat flows along the thermal path and drains out to the environment producing a temperature difference along its paths. At that time, the Heat Flux from the wall can be measured from the temperature difference between thermocouple junctions of a nickel-chrome pair. The micro Heat Flux Sensor is designed in the form of a circular foil gauge. Thermal resistance of the micro Heat Flux Sensor is perpendicular to the Heat Flux of the wall to increase the sensitivity of the Sensor. The calibration is accomplished under a convective environment. The sensitivity of the micro Heat Flux Sensor is in the range of 0.1/spl sim/10 /spl mu/V/(mW/cm/sup 2/) under the Heat Flux condition of 20/spl sim/350 mW/cm/sup 2/.
