The Experts below are selected from a list of 18786 Experts worldwide ranked by ideXlab platform
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: J. C. Jeon, S.h. OhAbstract: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 .
J. C. Jeon - 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
'Elsevier BV', 2019Co-Authors: Sh Lee, J. C. Jeon, Mh Kim, Ss 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 mu V/(mW cm(-2)) in the heat Flux range 0-180 mW/cm(2). (c) 2005 Elsevier B.V. All rights reserved.X115sciescopu
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bulk micromachined circular foil type micro heat Flux Sensor
Sensors and Actuators A-physical, 2006Co-Authors: J. C. Jeon, S.h. OhAbstract: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 .
Tom E. Diller - One of the best experts on this subject based on the ideXlab platform.
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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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Durable Heat Flux Sensor for Extreme Temperature and Heat Flux Environments
Journal of Thermophysics and Heat Transfer, 2010Co-Authors: Andrew Gifford, Clayton A. Pullins, David O. Hubble, Scott T Huxtable, Tom E. DillerAbstract:This paper reports on the development and evaluation of a novel heat Flux Sensor, the high-temperature heat Flux Sensor, tested at temperatures and heat Flux levels in excess of 1000°C and 10-13 W/cm 2 , respectively. The current Sensor configuration uses type-K thermocouple materials in a durable welded thermopile arrangement contained within a surface-mountable high-temperature housing. The steady-state sensitivity of the design is predicted using a simplified one-dimensional thermal-resistance model. The design performance of a prototype Sensor is validated using both conduction and convection heat transfer calibration at low temperature. The average experimental values of the sensitivity are 623 ± 33 mV/W/cm 2 and 579 ± 29 mV/W/cm 2 in conduction and convection, respectively. These calibration results compare very well with the predicted room-temperature sensitivity of 559 μV/W/cm 2 . Minimal dependence on heat transfer coefficient is found in convection. Prolonged thermal cycling of the Sensor using a high-temperature kiln and a propane torch apparatus demonstrates survivability near the maximum temperature of the thermoelectric materials with negligible oxidation or loss of calibration.
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, Kullervo Hynynen, Olli Pyrhonen, 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, Kullervo Hynynen, Olli Pyrhonen, 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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Local Heat Flux Measurement in a Permanent Magnet Motor at No Load
IEEE Transactions on Industrial Electronics, 2013Co-Authors: Hanne Jussila, A V Mityakov, Vladimir Y Mityakov, Sergey Z Sapozhnikov, Juha PyrhonenAbstract:Heat transfer is a limiting factor in the performance of electrical machines. Measuring the heat Flux in an electrical machine is traditionally carried out indirectly with temperature measurements as there are only a few Sensors for heat Flux measurements. This paper describes a new experimental method to measure the local heat Flux inside an electrical machine. The measurement was proven successful in the air gap of the permanent magnet machine, 37 kW 2400 min-1, under an influence of the air gap magnetic Flux. The heat Flux was measured by using Sensors based on the transverse Seebeck effect. The test machine was an axial Flux permanent magnet machine with two stator stacks and one internal, ironless rotor disc. A gradient heat Flux Sensor was installed in the air gap on the stator side. Local Nusselt and Reynolds numbers were calculated according to the measured heat Flux results and compared with the results given by traditional methods to verify the new measurement method.
Marcel Lacroix - One of the best experts on this subject based on the ideXlab platform.
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is the performance of a virtual Sensor employed for the prediction of the ledge thickness inside a metallurgical reactor affected by the thermal contact resistance
WIT transactions on engineering sciences, 2014Co-Authors: Marc Lebreux, Martin Desilets, Marcel LacroixAbstract:A virtual Sensor is developed for predicting the time-varying thickness of the ledge on the inside surface of a wall of a high-temperature metallurgical reactor. The virtual Sensor tracks the position of the solid-liquid phase front using thermal measurements taken from a heat Flux Sensor embedded in the reactor wall. The virtual Sensor comprises a state observer coupled to a reduced model of the reactor. It also accounts for the thermal contact resistance of the wall structure. Results indicate that the virtual Sensor is increasingly accurate as the magnitude of the thermal contact resistance augments. Moreover, the predictions of the virtual Sensor remain accurate even when the contact resistance is poorly known.
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an unscented kalman filter inverse heat transfer method for the prediction of the ledge thickness inside high temperature metallurgical reactors
International Journal of Heat and Mass Transfer, 2013Co-Authors: Marc Lebreux, Martin Desilets, Marcel LacroixAbstract:Abstract A non-intrusive inverse heat transfer procedure for predicting the time-varying thickness of the protective phase-change ledge on the inside surface of the walls of a high-temperature metallurgical reactor is presented. The inverse method, used here as a virtual Sensor, enables the on-line estimation of the position of the solid–liquid phase front using a heat Flux Sensor embedded in the reactor wall. The virtual Sensor comprises a state observer (Kalman filter) coupled to a state-space model of the reactor. Three different virtual Sensors are thoroughly tested: (1) an unscented Kalman filter with a nonlinear state-space model, (2) an extended Kalman filter with a nonlinear state-space model, and (3) a linear Kalman filter with a linear state-space model. Results show that the virtual Sensor composed of the unscented Kalman filter yields the best results for the operating conditions that prevail inside industrial facilities. Its predictions are more accurate than that of the linear Kalman filter, more stable than that of the extended Kalman filter, and its CPU time requirement is comparable to that of the other Sensors.
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control of the ledge thickness in high temperature metallurgical reactors using a virtual Sensor
Inverse Problems in Science and Engineering, 2012Co-Authors: Marc Lebreux, Martin Desilets, Marcel LacroixAbstract:A non-intrusive inverse heat transfer procedure for predicting the time-varying thickness of the phase change ledge on the inside surface of the walls of a high-temperature metallurgical reactor is presented. A Kalman filter, based on a state-space representation of the reactor, is coupled with a recursive least-square estimator in order to estimate online the position of the phase front. The data are collected by a heat Flux Sensor located inside or outside of the reactor wall. The inverse method, used here as a virtual Sensor, is coupled to a classic proportional–integral controller in order to control the ledge thickness by regulating the air cooling applied on the outside surface of the reactor wall. The virtual Sensor and the control strategy are thoroughly tested for typical phase change conditions that prevail inside industrial facilities. Results show that a virtual Sensor that relies on a heat Flux Sensor embedded inside the reactor wall provides more accurate and stable information, but at a pri...
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fast inverse prediction of phase change banks in high temperature furnaces with a kalman filter coupled with a recursive least square estimator
International Journal of Heat and Mass Transfer, 2010Co-Authors: Marc Lebreux, Martin Desilets, Marcel LacroixAbstract:An inverse heat transfer procedure for predicting the time-varying thickness of phase-change banks on the inside surface of the walls of high temperature furnaces is presented. The main feature of the inverse method is its unique capability of making fast predictions so that it can be easily integrated to existing real-time control systems of industrial facilities. The method rests on fast computing state-space models (direct model) that are designed to mimic the response of a full finite-difference model of the phase change problem. A Kalman filter coupled with a recursive least-square estimator (inverse method) is employed to estimate the time-varying phase front position from the data collected by a temperature and/or heat Flux Sensor located in the furnace wall. The inverse heat transfer procedure is thoroughly tested for typical phase change conditions that prevail inside industrial facilities. The effect of the Sensor type (temperature Sensor or heat Flux Sensor), of its location and of the measurement noise on the accuracy and stability of the predicted bank thickness is investigated. It is shown that the proposed inverse heat transfer procedure becomes increasingly reliable and accurate for predicting the bank thickness as it shrinks. This feature is of the utmost interest for preventing the sudden and accidental loss of the protective banks of industrial furnaces filled with molten material. Recommendations are also made concerning the type and location of Sensors.