The Experts below are selected from a list of 17250 Experts worldwide ranked by ideXlab platform
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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prediction of the time varying ledge profile inside a high temperature metallurgical Reactor with an unscented kalman filter based virtual sensor
Numerical Heat Transfer Part A-applications, 2013Co-Authors: Marc Lebreux, Martin Desilets, Marcel LacroixAbstract:A non-intrusive inverse heat transfer procedure for predicting the two-dimensional time-varying profile 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 thermal sensors embedded in the Reactor Wall. The virtual sensor comprises a state observer coupled to a reduced model of the Reactor. Results show that the virtual sensor that yields the best prediction comprises an unscented Kalman filter, a nonlinear state-space model of theReactor, and two heat flux sensors located at the Wall/ledge interface.
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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...
Evangelos Gogolides - One of the best experts on this subject based on the ideXlab platform.
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a global model for sf6 plasmas coupling reaction kinetics in the gas phase and on the surface of the Reactor Walls
Journal of Physics D, 2009Co-Authors: George Kokkoris, Andy Goodyear, Mike Cooke, Apostolos Panagiotopoulos, Evangelos GogolidesAbstract:Gas phase and Reactor Wall-surface kinetics are coupled in a global model for SF6 plasmas. A complete set of gas phase and surface reactions is formulated. The rate coefficients of the electron impact reactions are based on pertinent cross section data from the literature, which are integrated over a Druyvesteyn electron energy distribution function. The rate coefficients of the surface reactions are adjustable parameters and are calculated by fitting the model to experimental data from an inductively coupled plasma Reactor, i.e. F atom density and pressure change after the ignition of the discharge. The model predicts that SF6, F, F2 and SF4 are the dominant neutral species while and F? are the dominant ions. The fit sheds light on the interaction between the gas phase and the Reactor Walls. A loss mechanism for SFx radicals by deposition of a fluoro-sulfur film on the Reactor Walls is needed to predict the experimental data. It is found that there is a net production of SF5, F2 and SF6, and a net consumption of F, SF3 and SF4 on the Reactor Walls. Surface reactions as well as reactions between neutral species in the gas phase are found to be important sources and sinks of the neutral species.
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a global model for sf 6 plasmas coupling reaction kinetics in the gas phase and on the surface of the Reactor Walls
Journal of Physics D, 2009Co-Authors: George Kokkoris, Andy Goodyear, Mike Cooke, Apostolos Panagiotopoulos, Evangelos GogolidesAbstract:Gas phase and Reactor Wall-surface kinetics are coupled in a global model for SF6 plasmas. A complete set of gas phase and surface reactions is formulated. The rate coefficients of the electron impact reactions are based on pertinent cross section data from the literature, which are integrated over a Druyvesteyn electron energy distribution function. The rate coefficients of the surface reactions are adjustable parameters and are calculated by fitting the model to experimental data from an inductively coupled plasma Reactor, i.e. F atom density and pressure change after the ignition of the discharge. The model predicts that SF6, F, F2 and SF4 are the dominant neutral species while and F? are the dominant ions. The fit sheds light on the interaction between the gas phase and the Reactor Walls. A loss mechanism for SFx radicals by deposition of a fluoro-sulfur film on the Reactor Walls is needed to predict the experimental data. It is found that there is a net production of SF5, F2 and SF6, and a net consumption of F, SF3 and SF4 on the Reactor Walls. Surface reactions as well as reactions between neutral species in the gas phase are found to be important sources and sinks of the neutral species.
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Mechanisms of Oxygen Plasma Nanotexturing of Organic Polymer Surfaces: From Stable Super Hydrophilic to Super Hydrophobic Surfaces
Langmuir, 2009Co-Authors: K. Tsougeni, Evangelos Gogolides, N. Vourdas, A. Tserepi, Christophe CardinaudAbstract:Plasma processing is used to fabricate super hydrophilic or super hydrophobic polymeric surfaces by means of O-2 plasma etching of two organic polymers, namely, poly(methyl methacrylate) (PMMA) and poly(ether ether ketone) (PEEK); a C4F8 plasma deposition follows O-2 plasma etching, if surface hydrophobization is desired. We demonstrate high aspect ratio pillars with height ranging from 16 nm to several micrometers depending oil the processing time, and contact angle (CA) close to 0 degrees after O-2-Plasma treatment or CA of 153 degrees (with CA hysteresis lower than 5 degrees) after fluorocarbon deposition. Super hydrophobic surfaces are robust and stable in time; in addition, aging of super hydrophilic surfaces is significantly retarded because of the beneficial effect of the nanotextured topography. The mechanisms responsible for the plasma-induced PMMA and PEEK surface nanotexturing are unveiled through intelligent experiments involving intentional modification of the Reactor Wall material and X-ray photoelectron spectroscopy, which is also used to study the surface chemical modification in the plasma. We prove that control of plasma nanotexture call be achieved by carefully choosing the Reactor Wall material.
Marc Lebreux - 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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prediction of the time varying ledge profile inside a high temperature metallurgical Reactor with an unscented kalman filter based virtual sensor
Numerical Heat Transfer Part A-applications, 2013Co-Authors: Marc Lebreux, Martin Desilets, Marcel LacroixAbstract:A non-intrusive inverse heat transfer procedure for predicting the two-dimensional time-varying profile 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 thermal sensors embedded in the Reactor Wall. The virtual sensor comprises a state observer coupled to a reduced model of the Reactor. Results show that the virtual sensor that yields the best prediction comprises an unscented Kalman filter, a nonlinear state-space model of theReactor, and two heat flux sensors located at the Wall/ledge interface.
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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...
Jianfeng Lu - One of the best experts on this subject based on the ideXlab platform.
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heat transfer and energy storage performance of steam methane reforming in a tubular Reactor
Applied Thermal Engineering, 2017Co-Authors: Qinyuan Yuan, Rong Gu, Jing Ding, Jianfeng LuAbstract:Abstract Energy storage performance of steam methane reforming in a tubular Reactor is studied. According to the experimental results, high temperature thermal energy can be stored by steam methane reforming, and the thermochemical energy storage and sensible heat both have significant impacts. As the inlet flow rate is increased, the methane conversion decreases with the catalyst bed temperature and residence time dropping, while the efficiencies of thermochemical energy storage and total energy reach their maxima at optimal flow rates. Based on experimental validation, 3D flow and reaction model is developed using laminar finite-rate model to analyze steam methane reforming. Along the flow direction, the rates of main reaction and side reaction in catalyst bed first increase with the fluid temperate rising and then decrease with the decrement of reactant amount, so the Reactor Wall temperature has minimum near the front of bed for high chemical reaction rate. The thermochemical energy storage efficiency has maximum at optimal flow rate or optimal operating temperature, and associate maximum thermochemical energy storage efficiency and optimal flow rate increase with operating temperature rising. As a conclusion, low flow rate is suitable for low operating temperature, while higher one is suitable for high operating temperature. Based on maximum thermochemical energy storage efficiency, optimal Reactor diameter and optimal bed porosity can be further derived.
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high temperature energy storage performances of methane reforming with carbon dioxide in a tubular packed Reactor
Applied Energy, 2016Co-Authors: Jianfeng Lu, Yuan Chen, Weilong WangAbstract:High temperature heat transfer and energy storage performances of methane reforming with carbon dioxide in tubular packed Reactor are investigated under different operating conditions. Experimental results show that the methane reforming in tubular packed Reactor can efficiently store high temperature thermal energy, and the sensible heat and heat loss besides thermochemical energy storage play important role in the total energy storage process. When the operating temperature is increased, the thermochemical storage efficiency first increases for methane conversion rising and then decreases for heat loss rising. As the operating temperate is 800°C, the methane conversion is 79.6%, and the thermochemical storage efficiency and total energy efficiency can be higher than 47% and 70%. According to the experimental system, the flow and reaction model of methane reforming is established using the laminar finite-rate model and Arrhenius expression, and the simulated methane conversion and energy storage efficiency fit with experimental data. Along the flow direction, the fluid temperature in the catalyst bed first decreases because of the endothermic reaction and then increases for the heat transfer from Reactor Wall. As a conclusion, the maximum thermochemical storage efficiency will be obtained under optimal operating temperature and optimal flow rate, and the total energy efficiency can be increased by the increase of bed conductivity and decrease of heat loss coefficient.
Martin Desilets - 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.
-
prediction of the time varying ledge profile inside a high temperature metallurgical Reactor with an unscented kalman filter based virtual sensor
Numerical Heat Transfer Part A-applications, 2013Co-Authors: Marc Lebreux, Martin Desilets, Marcel LacroixAbstract:A non-intrusive inverse heat transfer procedure for predicting the two-dimensional time-varying profile 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 thermal sensors embedded in the Reactor Wall. The virtual sensor comprises a state observer coupled to a reduced model of the Reactor. Results show that the virtual sensor that yields the best prediction comprises an unscented Kalman filter, a nonlinear state-space model of theReactor, and two heat flux sensors located at the Wall/ledge interface.
-
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.
-
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...
