检索结果-内蒙古大学图书馆

An active learning workflow for predicting hydrogen atom adsorption energies on binary oxides based on local electronic transfer features

引用

Green Energy & Environment 2024年第10期9卷 1489-1496页

作者： Wenhao Jing Zihao Jiao Mengmeng Song Ya Liu Liejin Guo International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power EngineeringXi'an Jiaotong UniversityShaanxi710049Xi'anChina Department of Energy and Power Engineering Shandong University of TechnologyZibo255000ShandongChina

Machine learning combined with density functional theory(DFT)enables rapid exploration of catalyst descriptors space such as adsorption energy,facilitating rapid and effective catalyst ***,there is still a lack of models for predicting adsorption energies on oxides,due to the complexity of elemental species and the ambiguous coordination *** work proposes an active learning workflow(LeNN)founded on local electronic transfer features(e)and the principle of coordinate rotation *** accurately characterizing the electron transfer to adsorption site atoms and their surrounding geometric structures,LeNN mitigates abrupt feature changes due to different element types and clarifies coordination *** a result,it enables the prediction of^(*)H adsorption energy on binary oxide surfaces with a mean absolute error(MAE)below 0.18 ***,we incorporate local coverage(θ_(l))and leverage neutral network ensemble to establish an active learning workflow,attaining a prediction MAE below 0.2 eV for 5419 multi-^(*)H adsorption *** findings validate the universality and capability of the proposed features in predicting^(*)H adsorption energy on binary oxide surfaces.

关键词： Machine learning Adsorption energy Binary oxide Electron transfer Active learning

来源：评论

学校读者我要写书评

暂无评论

Time-resolved investigation of droplet size and velocity inside diesel fuel sprays 11

Time-resolved investigation of droplet size and velocity ins...

引用

11th Asia-Pacific Conference on Combustion, ASPACC 2017

作者： Feng, Zehao Zhang, Mingzhi Yang, Jiapei Tang, Chenglong Huang, Zuohua State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China

To better understand the microscopic spray characteristics, measurements of temporal changes in the size and velocity of droplets inside diesel fuel sprays were conducted at a fixed measurement position of 40mm downstream from the injector tip. Particle/droplet image analysis (PDIA) system was applied to obtain the microscopic droplet images in a long time scale (0-10 ms) which consists of continuous injection stage (0-2.1 ms) and the spray free development stage (2.1-10 ms). The results show that the droplet size distribution has a significant variation at the beginning, but basically independent of time after 1.6 ms. The Sauter mean diameter (SMD) increases significantly at the continuous injection stage, but slightly decreases at the free development stage. In addition, it is observed that most droplets’ velocity are 2-3 m/s while the maximum value is 25 m/s. An interesting similar bimodal shape of velocity distribution probability curves was found at different time after start of injection. What’s more, the scalar velocities gradually decrease as time goes on, but the direction of the velocities is messy due to the air entrainment. © 2018 Combustion Institute. All Rights Reserved.

关键词： Velocity

来源：评论

学校读者我要写书评

暂无评论

Shock tube and kinetic study of 1-pentene and N-pentane 10

Shock tube and kinetic study of 1-pentene and N-pentane

引用

10th Asia-Pacific Conference on Combustion, ASPACC 2015

作者： Cheng, Yu Hu, Erjiang Deng, Fuquan Yang, Feiyu Huang, Zuohua State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an Shaanxi China

Ignition delay times of the 1-pentene/O2/Ar mixtures and n-pentane/O2/Ar mixtures were measured behind the reflected shock wave at 10 atm, stoichiometric equivalence ratio, in the temperature range of 1100 K to 1580 K. Empirical correlations of the ignition delay time for 1-pentene and n-pentane were obtained through regression analysis. The simulations with the updated natural gas model show well agreement with the experimental data. Both the experimental and simulation results show a crossover in the ignition delay time of these two mixtures. Reaction pathways and sensitivity analysis are conducted to understand the oxidation process of 1-pentene and n-pentane. The chain branching reaction R1(H+O2O+OH) shows a strong promoting effect while the resonantly stablized allyl radical may be responsible for the longer ignition delay time of 1-pentene in the high temperature region.

关键词： Mixtures

来源：评论

学校读者我要写书评

暂无评论

Effect of hydrogen addition on early flame growth of lean burn natural gas-air mixtures 7

Effect of hydrogen addition on early flame growth of lean bu...

引用

7th Asia-Pacific Conference on Combustion, ASPACC 2009

作者： Wang, J.H. Huang, Z.H. Tang, C.L. Zheng, J.J. State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China

Effect of hydrogen addition on early flame growth of lean burn natural gas-air mixtures was investigated experimentally and numerically. The flame propagating photos and pressure derived initial combustion duration of premixed combustion and direct injection combustion was obtained by using a constant volume vessel. The laminar premixed methane-hydrogen-air flames were calculated with PREMIX code of CHEMKIN II program with GRI 3.0 mechanism. The results showed that the early flame growth of lean burn natural gas-air mixtures was enhanced as hydrogen is added to natural gas in the case of both premixed combustion and direct injection combustion. The mole fraction of OH and O are increased with the increase of hydrogen fraction and the position of maximum OH and O mole fraction move closing to the unburned mixture side. A monotonic correlation between initial combustion duration with the reciprocal maximum OH mole fraction in the flames is observed. The enhancement of the spark ignition of natural gas with hydrogen addition can be ascribed to the increase of OH and O mole fraction in the flames. © 2009 Combustion Institute. All rights reserved.

关键词： Natural gas

来源：评论

学校读者我要写书评

暂无评论

Thermo-economic optimization of the dual-pressure condenser for 700 °C ultra-supercritical coal-fired power plants

Thermo-economic optimization of the dual-pressure condenser ...

引用

2019 Canadian Society for Civil engineering Annual Conference, CSCE 2019

作者： Fu, Yue Liu, Ming Wang, Liyuan Yan, Junjie State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China

ISBN: (纸本)9780791883747

Pulverized coal power is one of major contributor in power production, whose efficiency can be enhanced by increasing the main steam parameters and adjusting the cold end system parameters. The thermo-economic optimization of the cold end system for 700 °C ultra-supercritical coal-fired power plants were carried out in this study. The condenser pressure was thermoeconomically optimized for the single-pressure condenser systems. Then, with the same heat transfer area of the optimized single-pressure condenser, the dual-pressure condenser system was thermo-economically optimized. The distributions of heat transfer area and exhaust steam mass flow between the highpressure and low-pressure chambers in the dual-pressure condenser system were optimized. The results show that the optimal vacuum pressure of the single-pressure condenser is 3 kPa and the optimal heat transfer area is 27 km2. For the dualpressure condenser system, the cost of dual-pressure condenser is reduced to the minimum value 1.3 million CNY/year. The power plant efficiency is increased by the maximum value 0.1% when the heat transfer area and exhaust steam mass flow rate are distributed equally between two chambers, compared with that of the single-pressure condenser system. The optimal values of the low-pressure and high-pressure chamber are 2.4 kPa and 3.2 kPa, respectively. This paper provides the reference for the design optimization of cold end system for high parameter power units. Copyright © 2020 ASME.

关键词： Coal fired power plant

来源：评论

学校读者我要写书评

暂无评论

MPS analysis of molten corium jet and structure interaction during nuclear severe accident 17

MPS analysis of molten corium jet and structure interaction ...

引用

17th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, NURETH 2017

作者： Li, Gen Zhang, Jun Yan, Junjie State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China

The melt jet and structure interaction is an important phenomenon in the progression of nuclear severe accident. It could happen when molten corium relocates onto core plate and Reactor Pressure Vessel (RPV) lower head, and in the ex-vessel accident, the molten corium may directly impinge onto and Erode concrete. In the present study, a numerical code was developed based on Moving Particle Semi-implicit (MPS) method, to analyze the erosion scenario of RPV wall and dry concrete by melt jet. The numerical modeling was validated by comparing structure erosion configuration and time-dependent erosion depth with the experimental data. In the analysis of RPV wall erosion, it indicates that no crust layer presented at the interaction of stainless steel (SS) melt jet and RPV wall, while for Zr, ZrO2 and UO2 melt jets the crust layer presented. At a superheat temperature equal to 300 K, the erosion rate by SS melt was the fastest, even though the absolute temperature was the lowest compared with other cases. In the analysis of melt jet and concrete interaction, the core melt was divided as metallic material (SS-Zr) and oxide material (ZrO2-UO2). The results indicate that the crust and ablated concrete layer presented at the interface of UO2-ZrO2 melt and concrete, whereas no crust could be found in the interaction of SS-Zr melt with concrete. The erosion progression was faster in the erosion by metallic melt jet than by oxidic melt jet. The present analysis demonstrates that the erosion rate was affected not only by temperature, but also by crust layer, and the major threat to structure was metallic melt, especially at high temperature. © 2016 Association for Computing Machinery Inc. All Rights Reserved.

关键词： Erosion

来源：评论

学校读者我要写书评

暂无评论

Time-domain study on the density wave oscillation of supercritical water in multiple parallel channel system 17

Time-domain study on the density wave oscillation of supercr...

引用

17th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, NURETH 2017

作者： Liu, Jialun Zhang, Qian Li, Huixiong Kong, Xiangfei Lei, Xianliang State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi'anShaanxi China

A time-domain model suitable for the study on the density wave instability of supercritical water in multiple parallel channel system (the number of channels is more than 2) was established. The present model developed an iterative solution to solve the coupling among parallel channels. Then the program was verified by the experimental data obtained in open literature. After that, the model was used to study the effect of system pressure (23-28 MPa), inlet fluid temperature (240-350 °C), and adding perturbation in different channels on the density wave instability of supercritical water in multiple parallel channel system. It was found that when the same perturbation was added on some of channels at the initial time (the other working conditions were kept unchanged), the number of perturbation channels had almost no effect on the oscillation period and the system stability. The stability of the multiple channel system increased with the increasing in system pressure. It was also found that a critical value about the inlet fluid temperature, denoted by Tin-cr, existed, and when the inlet fluid temperature was lower than the critical value Tin-cr, the stability of the multiple channel system dropped with the increase of inlet fluid temperature, and that was improved when inlet fluid temperature was higher than Tin-cr. The critical value Tin-cr increased gradually with the increasing in the amount of parallel channels. Moreover, Tin-cr was lower than and near the pseudo-critical temperature of supercritical water, and almost had no changes with varying system pressure. © 2016 Association for Computing Machinery Inc. All Rights Reserved.

关键词： System stability

来源：评论

学校读者我要写书评

暂无评论

Onset of slugging fluidization in supercritical water fluidized bed

引用

Particuology 2020年第5期18卷 47-56页

作者： Hao Wang Jikai Huang Youjun Lu State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong UniversityXi'an 710049ShaanxiChina Energy Research Insatute Qilu University of Technology(Shandong Academy of Sciences)Jinan 250014ShandongChina

The supercritical-water fluidized bed(SCWFB)is a reactor for coal and biomass gasification without pollutant *** carried out a series of experiments in a SCWFB,and a dual-capacitance probe measurement system was applied to measure the hydrodynamics of slugs,such as the slug frequency,chord length,and rising *** groups of Geldart-B particles with different mean diameters were fluidized by supercritical water with a system pressure of 20-27MPa and at 410-570℃.The minimum slugging Reynolds number increases logarithmically with Archimedes number and a predicting correlation of the minimum slugging fluidization velocity in the SCWFB is presented:Rems=32908.84 ln(Ar^0.55+260376.65)-*** relative error of the above correlation was within ±15% and the averaged relative error was 7.5%.The effect of operating conditions on the minimum slugging fluidization velocity is *** research provides useful guidance for scaling-up design and for determining the optimum range of operating conditions in the SCWFB.

关键词： Supercritical water fluidized bed Slugging fluidization Dual-capacitance probe method

来源：评论

学校读者我要写书评

暂无评论

Phenomenon of fog formation and flow characteristics of droplet-vapor-gas mixture in a cooler-condenser

Phenomenon of fog formation and flow characteristics of drop...

引用

ASME 2019 International Mechanical engineering Congress and Exposition, IMECE 2019

作者： Gu, Hongfang Guo, Qiwei Li, Changsong Zhou, Qing State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an Shaanxi China

ISBN: (纸本)9780791859452

Fog formation occurs in the process of condensation in the presence of non-condensable gas if the bulk temperature is lower than its saturation temperature (supersaturated). The phenomena of fogging is the formation of small condensate particles mixing with the vapor/gas stream, which creates potential problems of the vapor/gas/condensate separation and environmental pollution. Therefore, understanding of fogging mechanism and prevention of fog droplet entrainment are one of technical concerns for design and operation of cooler-condensers in the process industry. This paper presents the experimental study and numerical simulation of shell-side condensation with fog formation using a mixture of steam/non-condensable gas. The experimental data were collected on the two tube bundles (modified plastic tubes and stainless steel tubes). Using a high-speed photograph technique, the phenomenon of fog formation and flow characteristics of vapor/droplet transport were recorded over a wide range of test conditions. The numerical analysis of film and dropwise condensation, fog formation and droplet particle transport were simulated using different tube geometry and material, and flow velocity of air/droplet mixture. Based on simulation results, a new droplet trapping parameter is proposed to assess the optimal parameters of heat exchanger structural and operation conditions. Comparisons show that the numerical analysis results have a good agreement with experimental data and observations. These findings provide fundamental approach to account for the effect of fog formation, film and dropwise condensation, and droplet transport crossflow in cooler-condensers. Copyright © 2019 ASME.

关键词： Drops

来源：评论

学校读者我要写书评

暂无评论

Shock-tube measurements and kinetic study of propanal ignition 10

Shock-tube measurements and kinetic study of propanal igniti...

引用

10th Asia-Pacific Conference on Combustion, ASPACC 2015

作者： Yang, Ke Tang, Chenglong Man, Xingjia Huang, Zuohua State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an Shaanxi China

Ignition delay times of propanal were measured in a shock tube over the temperature range of 1050-1800 K, pressures of 1.2-16 atm, fuel concentrations of 0.5-2.0%, and equivalence ratios of 0.5-2.0. Through multiple linear regression, a correlation for the tested ignition delay times was obtained, and the measured data were also compared to the previous data. Two available models (Veloo mech and NUIG mech), were used to simulate the experimental data. Results suggest that both mechanisms has its own advantages and the Veloo mech exhibits a better prediction on the measured data than NUIG mech except for the fuel-rich condition. Reaction pathway analysis indicates that propanal molecule mainly breaks down through the H-abstraction reactions (accounting for around 80% propanal consumption), while reactions of unimolecular decomposition contribute a little part of the whole consumption.

关键词： Shock tubes

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：