The Experts below are selected from a list of 315 Experts worldwide ranked by ideXlab platform
Ming-xing Wang - One of the best experts on this subject based on the ideXlab platform.
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Effect of cooling rate on Ignition Point of AZ91D–0.98 wt.% Ce magnesium alloy
Materials Letters, 2007Co-Authors: Wenjiang Li, W. Zhou, Wanjun Li, Hongwei Zhou, Ming-xing WangAbstract:Abstract Influence of the cooling rate, K p , on the Ignition Point of AZ91D–0.98 wt.% Ce magnesium alloy is investigated. To the AZ91D–0.98 wt.% Ce magnesium alloy, the cooling rate has a great effect on its microstructure and phase. XRD shows that it mainly consists of α-Mg, Mg 17 Al 12 and Ce phases with rapid solidification treatment, while α-Mg, Mg 17 Al 12 and Al 11 Ce 3 phases are with air cooling and furnace cooling treatments. Compared with alloys with different cooling rates, the higher the cooling speed, the higher the Ignition Point, and this is because the solid solution of Ce in the AZ91D alloy is controlled by the cooling speed.
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effect of cooling rate on Ignition Point of az91d 0 98 wt ce magnesium alloy
Materials Letters, 2007Co-Authors: Wenjiang Li, W. Zhou, Wanjun Li, Hongwei Zhou, Ming-xing WangAbstract:Abstract Influence of the cooling rate, K p , on the Ignition Point of AZ91D–0.98 wt.% Ce magnesium alloy is investigated. To the AZ91D–0.98 wt.% Ce magnesium alloy, the cooling rate has a great effect on its microstructure and phase. XRD shows that it mainly consists of α-Mg, Mg 17 Al 12 and Ce phases with rapid solidification treatment, while α-Mg, Mg 17 Al 12 and Al 11 Ce 3 phases are with air cooling and furnace cooling treatments. Compared with alloys with different cooling rates, the higher the cooling speed, the higher the Ignition Point, and this is because the solid solution of Ce in the AZ91D alloy is controlled by the cooling speed.
Wenjiang Li - One of the best experts on this subject based on the ideXlab platform.
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Effect of cooling rate on Ignition Point of AZ91D–0.98 wt.% Ce magnesium alloy
Materials Letters, 2007Co-Authors: Wenjiang Li, W. Zhou, Wanjun Li, Hongwei Zhou, Ming-xing WangAbstract:Abstract Influence of the cooling rate, K p , on the Ignition Point of AZ91D–0.98 wt.% Ce magnesium alloy is investigated. To the AZ91D–0.98 wt.% Ce magnesium alloy, the cooling rate has a great effect on its microstructure and phase. XRD shows that it mainly consists of α-Mg, Mg 17 Al 12 and Ce phases with rapid solidification treatment, while α-Mg, Mg 17 Al 12 and Al 11 Ce 3 phases are with air cooling and furnace cooling treatments. Compared with alloys with different cooling rates, the higher the cooling speed, the higher the Ignition Point, and this is because the solid solution of Ce in the AZ91D alloy is controlled by the cooling speed.
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effect of cooling rate on Ignition Point of az91d 0 98 wt ce magnesium alloy
Materials Letters, 2007Co-Authors: Wenjiang Li, W. Zhou, Wanjun Li, Hongwei Zhou, Ming-xing WangAbstract:Abstract Influence of the cooling rate, K p , on the Ignition Point of AZ91D–0.98 wt.% Ce magnesium alloy is investigated. To the AZ91D–0.98 wt.% Ce magnesium alloy, the cooling rate has a great effect on its microstructure and phase. XRD shows that it mainly consists of α-Mg, Mg 17 Al 12 and Ce phases with rapid solidification treatment, while α-Mg, Mg 17 Al 12 and Al 11 Ce 3 phases are with air cooling and furnace cooling treatments. Compared with alloys with different cooling rates, the higher the cooling speed, the higher the Ignition Point, and this is because the solid solution of Ce in the AZ91D alloy is controlled by the cooling speed.
Rastko Jovanovic - One of the best experts on this subject based on the ideXlab platform.
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sensitivity analysis of different devolatilisation models on predicting Ignition Point position during pulverized coal combustion in o2 n2 and o2 co2 atmospheres
Fuel, 2012Co-Authors: Rastko Jovanovic, Aleksandra Milewska, Bartosz Swiatkowski, Adrian Goanta, H SpliethoffAbstract:Oxy-fuel combustion is considered as a promising solution to reduce greenhouse-gases and pollutant emissions. The main advantage of oxy-fuel combustion over other technologies for pollution reduction from pulverized coal combustion is that it can be applied to the existing coal-fired power plants. However, switching from conventional to oxy-fired coal combustion brings significant challenges. One of the most important is change of pulverized coal Ignition characteristics. This paper presents the results of experimental and numerical analysis of Ignition phenomena under oxy-fuel conditions. The main focus of the presented paper is to evaluate the effectiveness of the mathematical devolatilisation sub-model, in predicting the Ignition Point of pulverized coal flames under oxy-firing conditions. Regarding this, the performance of several devolatilisation models, from simple to more complex ones, in predicting Ignition Point position have been investigated. Numerically determined values of the Ignition Point position, and Ignition temperature for various O-2-N-2 and O-2-CO2 conditions were compared with experimental data from the laboratory Ignition test facility. Obtained results Pointed out that network devolatilisation models (CPD and FG) give more accurate results in comparison with standard devolatilisation models (single rate and two competing rates). The best performance is achieved using FG devolatilisation model. Thus, newly implemented FG model will be used for future numerical simulations of oxy-fuel pulverized coal combustion on 0.5 MW pilot plant facility. (C) 2011 Elsevier Ltd. All rights reserved.
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numerical investigation of influence of homogeneous heterogeneous Ignition combustion mechanisms on Ignition Point position during pulverized coal combustion in oxygen enriched and recycled flue gases atmosphere
International Journal of Heat and Mass Transfer, 2011Co-Authors: Rastko Jovanovic, Aleksandra Milewska, Bartosz Swiatkowski, Adrian Goanta, H SpliethoffAbstract:It is expected that pulverized coal combustion will continue to play a major role in electricity generation for the foreseeable future. Oxy-fuel coal combustion is actively being investigated, as alternative to conventional pulverized-coal combustion, due to its potential to easier carbon dioxide sequestration. This paper presents experimental and numerical analysis of Ignition phenomena in oxy-fuel conditions. A modification of standard sequential coal combustion model is proposed. The new model is developed following the criteria for the particle Ignition mechanism as the function of surrounding conditions. The implemented model was validated based on Ignition Point position obtained from the drop tube facility experiments in various O2–N2 and O2–CO2 conditions. The obtained numerical results showed a much better agreement with the experimental results when compared with the simulations performed with the default FLUENT sub-models for coal particle Ignition/combustion, thus enabling a quantitative determination of pulverized coal flame Ignition Point position using numerical analysis.
H Spliethoff - One of the best experts on this subject based on the ideXlab platform.
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sensitivity analysis of different devolatilisation models on predicting Ignition Point position during pulverized coal combustion in o2 n2 and o2 co2 atmospheres
Fuel, 2012Co-Authors: Rastko Jovanovic, Aleksandra Milewska, Bartosz Swiatkowski, Adrian Goanta, H SpliethoffAbstract:Oxy-fuel combustion is considered as a promising solution to reduce greenhouse-gases and pollutant emissions. The main advantage of oxy-fuel combustion over other technologies for pollution reduction from pulverized coal combustion is that it can be applied to the existing coal-fired power plants. However, switching from conventional to oxy-fired coal combustion brings significant challenges. One of the most important is change of pulverized coal Ignition characteristics. This paper presents the results of experimental and numerical analysis of Ignition phenomena under oxy-fuel conditions. The main focus of the presented paper is to evaluate the effectiveness of the mathematical devolatilisation sub-model, in predicting the Ignition Point of pulverized coal flames under oxy-firing conditions. Regarding this, the performance of several devolatilisation models, from simple to more complex ones, in predicting Ignition Point position have been investigated. Numerically determined values of the Ignition Point position, and Ignition temperature for various O-2-N-2 and O-2-CO2 conditions were compared with experimental data from the laboratory Ignition test facility. Obtained results Pointed out that network devolatilisation models (CPD and FG) give more accurate results in comparison with standard devolatilisation models (single rate and two competing rates). The best performance is achieved using FG devolatilisation model. Thus, newly implemented FG model will be used for future numerical simulations of oxy-fuel pulverized coal combustion on 0.5 MW pilot plant facility. (C) 2011 Elsevier Ltd. All rights reserved.
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Sensitivity analysis of different devolatilisation models on predicting Ignition Point position during pulverized coal combustion in O2/N2 and O2/CO2 atmospheres
Fuel, 2012Co-Authors: Rastko Jovanović, Aleksandra Milewska, Bartosz Swiatkowski, Adrian Goanta, H SpliethoffAbstract:Oxy-fuel combustion is considered as a promising solution to reduce greenhouse-gases and pollutant emissions. The main advantage of oxy-fuel combustion over other technologies for pollution reduction from pulverized coal combustion is that it can be applied to the existing coal-fired power plants. However, switching from conventional to oxy-fired coal combustion brings significant challenges. One of the most important is change of pulverized coal Ignition characteristics. This paper presents the results of experimental and numerical analysis of Ignition phenomena under oxy-fuel conditions. The main focus of the presented paper is to evaluate the effectiveness of the mathematical devolatilisation sub-model, in predicting the Ignition Point of pulverized coal flames under oxy-firing conditions. Regarding this, the performance of several devolatilisation models, from simple to more complex ones, in predicting Ignition Point position have been investigated. Numerically determined values of the Ignition Point position, and Ignition temperature for various O-2-N-2 and O-2-CO2 conditions were compared with experimental data from the laboratory Ignition test facility. Obtained results Pointed out that network devolatilisation models (CPD and FG) give more accurate results in comparison with standard devolatilisation models (single rate and two competing rates). The best performance is achieved using FG devolatilisation model. Thus, newly implemented FG model will be used for future numerical simulations of oxy-fuel pulverized coal combustion on 0.5 MW pilot plant facility. (C) 2011 Elsevier Ltd. All rights reserved.
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Numerical investigation of influence of homogeneous/heterogeneous Ignition/combustion mechanisms on Ignition Point position during pulverized coal combustion in oxygen enriched and recycled flue gases atmosphere
International Journal of Heat and Mass Transfer, 2011Co-Authors: Rastko Jovanović, Aleksandra Milewska, Bartosz Swiatkowski, Adrian Goanta, H SpliethoffAbstract:It is expected that pulverized coal combustion will continue to play a major role in electricity generation for the foreseeable future. Oxy-fuel coal combustion is actively being investigated, as alternative to conventional pulverized-coal combustion, due to its potential to easier carbon dioxide sequestration. This paper presents experimental and numerical analysis of Ignition phenomena in oxy-fuel conditions. A modification of standard sequential coal combustion model is proposed. The new model is developed following the criteria for the particle Ignition mechanism as the function of surrounding conditions. The implemented model was validated based on Ignition Point position obtained from the drop tube facility experiments in various O2–N2 and O2–CO2 conditions. The obtained numerical results showed a much better agreement with the experimental results when compared with the simulations performed with the default FLUENT sub-models for coal particle Ignition/combustion, thus enabling a quantitative determination of pulverized coal flame Ignition Point position using numerical analysis.
Giuseppe Amatulli - One of the best experts on this subject based on the ideXlab platform.
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mapping lightning human caused wildfires occurrence under Ignition Point location uncertainty
Ecological Modelling, 2007Co-Authors: Giuseppe Amatulli, Fernando Perezcabello, Juan De La RivaAbstract:Fire managers need to study fire history in terms of occurrence in order to understand and model the spatial distribution of the causes of Ignition. Fire atlases are useful open sources of information, recording each single fire event by means of its geographical position. In such cases the fire event is considered as Point-based, rather than area-based data, completely losing its surface nature. Thus, an accurate method is needed to estimate continuous density surfaces from Ignition Points where location is affected by a certain degree of uncertainty. Recently, the fire scientific community has focused its attention on the kernel density interpolation technique in order to convert Point-based data into continuous surface or surface-data. The kernel density technique needs a priori setting of smoothing parameters, such as the bandwidth size. Up to now, the bandwidth size was often based on subjective choices still needing expert knowledge, eventually supported by empirical decisions, thus leading to serious uncertainties. Nonetheless, a geostatistical model able to describe the Point concentration and consequently the clustering degree is required. This paper tries to solve such issues by implementing the kernel density adaptive mode. Lightning/human-caused fires occurrence was investigated in the region of Aragon's autonomy over 19 years (1983–2001) using 3428 and 4195 Ignition Points respectively for the two causes of fire origin. An analytical calibration procedure was implemented to select the most reliable density surfaces to reduce under/over-density estimation, overcoming the current drawbacks to define it by visual inspection or personal interpretation. Besides, Ignition Point location uncertainty was investigated to check the sensitivity of the proposed model. The different concentration degree and the dissimilar spatial pattern of the two datasets, allow testing the proposed calibration methodology under several conditions. After having discovered the slight sensitivity of the model to the exact Point position, the obtained density surfaces for the two causes were combined to discover hotspot areas and spatial patterns of the two causes. Evident differences in spatial location of the origin causes were noted and described. The general trend follows the geographical features and the human activity of the study areas. The proposed technique should be promising to support decision-making in wildfire prevention actions, because of the occurrence map can be used as a response variable in fire risk predicting models.
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Mapping lightning/human-caused wildfires occurrence under Ignition Point location uncertainty
Ecological Modelling, 2007Co-Authors: Giuseppe Amatulli, Fernando Pérez-cabello, Juan De La RivaAbstract:Fire managers need to study fire history in terms of occurrence in order to understand and model the spatial distribution of the causes of Ignition. Fire atlases are useful open sources of information, recording each single fire event by means of its geographical position. In such cases the fire event is considered as Point-based, rather than area-based data, completely losing its surface nature. Thus, an accurate method is needed to estimate continuous density surfaces from Ignition Points where location is affected by a certain degree of uncertainty. Recently, the fire scientific community has focused its attention on the kernel density interpolation technique in order to convert Point-based data into continuous surface or surface-data. The kernel density technique needs a priori setting of smoothing parameters, such as the bandwidth size. Up to now, the bandwidth size was often based on subjective choices still needing expert knowledge, eventually supported by empirical decisions, thus leading to serious uncertainties. Nonetheless, a geostatistical model able to describe the Point concentration and consequently the clustering degree is required. This paper tries to solve such issues by implementing the kernel density adaptive mode. Lightning/human-caused fires occurrence was investigated in the region of Aragon's autonomy over 19 years (1983–2001) using 3428 and 4195 Ignition Points respectively for the two causes of fire origin. An analytical calibration procedure was implemented to select the most reliable density surfaces to reduce under/over-density estimation, overcoming the current drawbacks to define it by visual inspection or personal interpretation. Besides, Ignition Point location uncertainty was investigated to check the sensitivity of the proposed model. The different concentration degree and the dissimilar spatial pattern of the two datasets, allow testing the proposed calibration methodology under several conditions. After having discovered the slight sensitivity of the model to the exact Point position, the obtained density surfaces for the two causes were combined to discover hotspot areas and spatial patterns of the two causes. Evident differences in spatial location of the origin causes were noted and described. The general trend follows the geographical features and the human activity of the study areas. The proposed technique should be promising to support decision-making in wildfire prevention actions, because of the occurrence map can be used as a response variable in fire risk predicting models.
