检索结果-内蒙古大学图书馆

An effective method for modeling 1D two-phase two-fluid six-equation model with automatic differentiation approach

PROGRESS IN NUCLEAR ENERGY 2022年 151卷

作者： Niu, Yuhang He, Yanan Qiu, Bowen Xiang, Fengrui Deng, Chaoqun Li, Yuanming Zhang, Jing Wu, Yingwei Tian, Wenxi Qiu, Suizheng Xi An Jiao Tong Univ Sch Nucl Sci & Technol Xian 710049 Shaanxi Peoples R China Xi An Jiao Tong Univ Shaanxi Key Lab Adv Nucl Energy & Technol Xian 710049 Peoples R China Xi An Jiao Tong Univ State Key Lab Multiphase Flow Power Engn Xian 710049 Peoples R China Nucl Power Inst China Sci & Technol Reactor Syst Design Technol Lab Chengdu Peoples R China 28 Xianning West Rd Xian Peoples R China

The modeling of the two-fluid model with plenty of realistic closure correlations has been a tough problem because of the difficulty of forming the Jacobian matrix manually. To predict the phase appearance/disappearance in two-phase flow problems, the high-order spatial and fully implicit temporal discretization typically should be adopted. However, considering the requirement of a fairly accurate evaluation of the Jacobian matrix, the implementation of high-order schemes is a challenging task. In this study, the automatic differentiation (AD) method was employed to overcome these difficulties, which seems the first demonstration of the high-order scheme and the AD method in the two-fluid model with realistic relations. With the AD method, the highorder fully implicit scheme, and the preconditioned Jacobian-free Newton-Krylov (PJFNK) method, the twofluid code was developed to solve the two-phase flow and heat transfer problems in this study. Through simulations of a series of hydrodynamics two-phase flow problems, this code was verified and validated in both transients and boiling conditions. Meanwhile, code-to-code comparisons with well-validated code, RELAP5, were presented. The results demonstrate the promising performance of the developed code for solving 1D two-phase flow problems.

关键词： Two -fluid model Automatic differentiation High -order discretization flow and heat transfer

来源：评论

学校读者我要写书评

暂无评论

MoO₃/g-C₃N₄ Z-scheme (S-scheme) system derived from MoS₂/melamine dual precursors for enhanced photocatalytic H₂ evolution driven by visible light

引用

INTERNATIONAL JOURNAL OF HYDROGEN ENERGY 2021年第3期46卷 2927-2935页

作者： Shi, Jinwen Zheng, Botong Mao, Liuhao Cheng, Cheng Hu, Yuchao Wang, Heng Li, Gaosheng Jing, Dengwei Liang, Xianglong Xian Jiaotong Univ XJTU State Key Lab Multiphase Flow Power Engn MFPE Int Res Ctr Renewable Energy IRCRE 28 West Xianning Rd Xian 710049 Peoples R China Xian Jiaotong Univ XJTU Sch Energy & Power Engn 28 West Xianning Rd Xian 710049 Peoples R China Univ Elect Sci & Technol China Ctr Appl Chem Chengdu 610000 Sichuan Peoples R China PetroChina West Pipeline Co Urumqi 830013 Peoples R China PetroChina Changqing Oilfield Co PCOC Xian 710018 Peoples R China

A dual-precursors co-pyrolysis strategy was adopted to prepare photocatalysts of MoO3/gC(3)N(4) composite from MoS2/melamine through a facile one-pot method. By following this strategy, MoS2 was in-situ transformed to MoO3 accompanying with the pyrolysis and polymerization of melamine to g-C3N4 nanosheets. A set of samples about MoO3/g-C3N4 composite containing different MoO3 contents were prepared and the visible-light driven photocatalytic performance of samples were investigated. The photocatalytic activity was notably enhanced and the highest evolution rate for H-2 reached 13.9 times and 2.5 times that of the pristine g-C3N4 and the MoO3/g-C3N4 derived from MoO3/melamine, respectively. On the one hand, layered MoS2 used as the precursor of MoO3 contributed to the intimate contact with g-C3N4 nanosheets and the high dispersity of derived MoO3, and on the other hand, the morphology and electronic structure of g-C3N4 were actually changed by the strong interaction between the MoO3 and g-C3N4, thus inducing an efficient Z scheme (S-scheme) system in the composite. The above-mentioned co-operation effect in the composite resulted in the significant improvement on the activity of photocatalytic H-2 evolution. This work presented a valuable reference, by taking MoO3/g-C3N4 as an example, for the construction of composite-photocatalyst system in visible-light-driven H-2 evolution. (c) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

关键词： Molybdenum trioxide Molybdenum disulfide Graphitic carbon nitride Hydrogen One-pot method

来源：评论

学校读者我要写书评

暂无评论

Experimental study on fouling and slagging behaviors during oxy-fuel combustion of high-sodium coal using a high-temperature drop-tube furnace

引用

INTERNATIONAL JOURNAL OF GREENHOUSE GAS CONTROL 2020年 97卷

作者： Wang, Chang'an Sun, Ruijin Zhao, Lei Wang, Chaowei Hu, Guangtao Zhao, Nan Che, Defu Xi An Jiao Tong Univ State Key Lab Multiphase Flow Power Engn Sch Energy & Power Engn Xian 710049 Peoples R China

Zhundong coalfield occupies an important position in Chinese energy resource. However, the high-sodium content has become the hindrance for the safe use of Zhundong coal, leading to severe fouling and slagging issues. Oxy-fuel combustion is a clean combustion technology and beneficial for capturing CO2. The fouling/slagging mechanisms of Zhundong coal in oxy-fuel combustion were ambiguous and the influences of oxygen content on the slagging behaviors of high-sodium coal have yet to be fully understood. This work employed a drop-tube furnace to explore the effects of flue gas temperature and oxygen content on the fouling and slagging characteristics in oxy-fuel atmosphere, and also conducted the comparison between oxy-fuel and air cases, with the elaboration of mineral constituents, morphologies, and elemental compositions of the deposits. Experimental results showed that the fouling of the high-sodium coal worsened as the flue gas temperature rose from 900 degrees C to 1200 degrees C. The element and mineral categories of the slag were similar but the relative contents of the mineral were different between oxy-fuel and air conditions. The diffraction peak of quartz in Wucaiwan slag during oxy-fuel combustion was weaker than that in air, while the condition of Lu'an slag was different. The high sodium content and its compounds promoted the formation of initial layer and the sticky particle surface, worsening the fouling and slagging. More comprehensive understanding of slagging mechanism could be achieved through the present work, which made sense for the optimization of combustion condition and the safe utilization of Zhundong coal.

关键词： oxy-fuel combustion high-sodium coal slagging mineral constituent morphology CO2 capture technology

来源：评论

学校读者我要写书评

暂无评论

Nitromethane pyrolysis and oxidation in a jet-stirred reactor: Experimental measurements, kinetic model validation and interpretation

引用

FUEL 2020年 263卷

作者： Yang, Meng Gao, Zhongquan Tang, Chenglong Xu, Zhaohua Gao, Zhenhua Hu, Erjiang Huang, Zuohua Xi An Jiao Tong Univ State Key Lab Multiphase Flow Power Engn Xian 710049 Shaanxi Peoples R China

A jet-stirred reactor was used to investigate the nitromethane pyrolysis and oxidation characteristics over the temperature range of 675-1250 K at atmospheric pressure. Mole fraction profiles of reactants, intermediate hydrocarbon species and products were identified using gas chromatography and gas chromatography-mass spectrometer. Results show that the fuel begins to be destructed at around 725 K and completely vanishes at 900 K for all experimental conditions. Pyrolysis of nitromethane as a function of temperature shows three distinct regions for H-2, CO and C2H4 species. In addition, a negative temperature coefficient (NTC) behavior of CO2 species for nitromethane oxidation was observed, which has never been reported previously. The NTC region of CO2 species extends with the increase of equivalence ratio. These measured data were then used to validate several recently developed models of nitromethane. Results show that the model of Mathieu et al. (Mathieu et al. Fuel 182(2016):597) predicts the measured data well at low temperature (below 900 K) for all conditions. However, at intermediate temperature Mathieu model predicted intermediated species and main products deviate noticeably from measured data. Detailed reaction pathway analysis was conducted to direct future model refinement. Results show that the deviation between model predictions and measurements at intermediate temperature may be attributed to the reactions that involve the H and OH radicals. Further comparisons of the sensitive reactions for H and OH formations from different literatures were conducted, and large deviations in rate constants among these reactions suggest the directions of future model refinement.

关键词： Jet-stirred reactor Nitromethane Pyrolysis Oxidation Kinetic model analysis

来源：评论

学校读者我要写书评

暂无评论

Preparation and properties of multifunctional eco-friendly slow-release urea fertilizer encapsulated by diatomite filter aid waste-based superabsorbent

引用

PROGRESS IN ORGANIC COATINGS 2023年 183卷

作者： Dong, Zhihui Qu, Nan Jiang, Qiushi Han, Zhaolian Sun, Lianzhi Zhang, Tong Liang, Dong Shi, Yiran Cheng, Zhiqiang Jilin Agr Univ Coll Resources & Environm Changchun 130118 Peoples R China Xi An Jiao Tong Univ State Key Lab Multiphase Flow Power Engn Xianning West Rd Xian 710049 Peoples R China Jilin Agr Univ Coll Hort Changchun 130118 Peoples R China Jilin Agr Univ Coll Informat Technol Changchun 130118 Peoples R China Korean Autonomous Cty Changbai Jinyuan Diatomite P Jilin 134300 Peoples R China

Due to the high cost, incomplete degradation, and limited raw material sources of traditional slow-release fertilizers, the development of environmentally friendly slow-release urea based on waste filter aids is of great significance in modern agriculture. In this study, beer diatomite filter aid waste-based superabsorbent resin (BDWSA)1 was synthesized by free radical grafting copolymerization through microwave radiation heating with beer diatomite filter aid waste (BDW), acrylic acid (AA), N, N-methylenebisacrylamide (MBA), and potassium persulfate (KPS). Then, BDWSA was used as the outer coating material, along with ethyl cellulose (EC) and Kaolin as the inner coating, urea and Phellinus igniarius biochar as the fertilizer core, to form a multifunctional eco-friendly double-coated slow-release urea (DSRU) for water-retaining and slow-release functionalities. The performance of slow release behavior of nitrogen was investigated, and showed that urea in soil released 86.02 % of nitrogen during 3 days, monolayer-coated slow-release urea (MSRU) released 94.02 % of nitrogen in 30 days, and DSRU released a total of 74.66 % of nitrogen in 30 days, indicating that DSRU can improve fertilizer utilization by delaying nutrient release. The biodegradation experiment showed that DSRU degraded 86.65 % wt% in 90 days, not only indicating a good biodegradation effect but also beneficial to the growth of soybeans under drought conditions in growth experiments. Therefore, the eco-friendly DSRU product with excellent slow-release capacity has broad application prospects in agriculture.

关键词： Diatomite filter aid waste Superabsorbent resin Slow-release coated urea Nitrogen release Biodegradability

来源：评论

学校读者我要写书评

暂无评论

Regeneration of iron fuel in fluidized beds, Part I: Defluidization experiments and theoretical prediction model

引用

POWDER TECHNOLOGY 2023年 420卷

作者： Liu, X. Zhang, X. Li, J. Zhu, Q. Deen, N. G. Tang, Y. Eindhoven Univ Technol Dept Mech Engn Power & Flow Grp POB 513 NL-5600 MB Eindhoven Netherlands Chinese Acad Sci Inst Proc Engn State Key Lab Multiphase Complex Syst Beijing 100190 Peoples R China Univ Chinese Acad Sci Sch Chem Engn Beijing 100049 Peoples R China Eindhoven Univ Technol Eindhoven Inst Renewable Energy Syst EIRES POB 513 NL-5600 MB Eindhoven Netherlands

Hydrogen-based direct reduction of iron oxide powder in gas-fluidized beds has become an emerging technology. Agglomeration of fine powder at elevated temperatures is however one key issue hindering the technological development. To obtain better knowledge of the high-temperature agglomeration mechanism, the (de-)fluidization behavior of micron-sized combusted iron particles is experimentally studied in this Part I. Effects of various operating and material variables (temperature, gas flow rate, and particle size) on the fluidization and agglomeration behavior are investigated. Different fluidization regimes (e.g. stable fluidization, agglomerating fluidization, fast defluidization) are categorized based on the experimental results. A theoretical model based on the force balance is developed to predict the regime boundaries of fluidization. The obtained knowledge is applied for experimental design of the hydrogen-based iron direct reduction process in Part II.

关键词： Iron oxide powder Gas-fluidized beds Agglomeration High temperature (De-)fluidization Force balance

来源：评论

学校读者我要写书评

暂无评论

Thermal analysis on a nanofluid-filled rectangular cavity with heated fins of different geometries under magnetic field effects

引用

JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY 2020年第6期139卷 3577-3588页

作者： Jing, Dengwei Hu, Songwei Hatami, M. Xiao, Yuanxiang Jia, Jianpeng Xi An Jiao Tong Univ Int Res Ctr Renewable Energy State Key Lab Multiphase Flow Power Engn Xian Peoples R China Esfarayen Univ Technol Dept Mech Engn Esfarayen North Khorasan Iran Changqing Oilfield Co Oil & Gas Technol Res Inst Xian 710018 Peoples R China

Rectangular cavity filled with a non-Newtonian shear-thinning nanofluid was investigated considering varied fin geometry under a vertical magnetic field. Irreversibility and entropy generation mechanisms were investigated by finite element method. The effect of geometry parameter (a), Hartmann number (Ha), nanoparticles volume fraction (phi) and nanoparticles type (Fe3O4, CuO and Al2O3) on the Nusselt numbers, entropy generations and Bejan numbers were investigated by the response surface methodology (RSM). Increasing a leads to an increase in both local and average Nusselt numbers and increment in different terms of entropy generation, while it reduces the Bejan number. Fe3O4 nanoparticle shows the highest Nusselt number compared to other nanoparticles. RSM analysis revealed that a = 0.29 and phi = 0.04 are the optimized values for the goal of maximum Nusselt number and minimum Bejan number.

关键词： Entropy generation Irreversibility Non-Newtonian nanofluid Bejan number Nusselt number

来源：评论

学校读者我要写书评

暂无评论

Lateral Fully Organic P-N Diodes Created in a Single Donor-Acceptor Copolymer

引用

ADVANCED MATERIALS 2022年第5期34卷 e2106624页

作者： Wang, Jing Wang, Yizhuo Li, Kuncai Dai, Xu Zhang, Liuyang Wang, Hong Xi An Jiao Tong Univ Frontier Inst Sci & Technol Xian 710054 Peoples R China Xi An Jiao Tong Univ Sch Mech Engn Xian 710054 Peoples R China Xi An Jiao Tong Univ State Key Lab Multiphase Flow Power Engn Xian 710054 Peoples R China Xi An Jiao Tong Univ Sch Energy & Power Engn Xian 710054 Peoples R China

P-N junctions exist in many solid-state organic devices, such as light-emitting diodes, solar cells, and thermoelectric devices. Creating P-N junctions by bulk chemical doping in a single organic material (like silicon doped by boron and phosphorus) may capitalize the vast scientific and technological groundwork established in the inorganic semiconducting field. However, high-performance single-organic-material P-N junctions are seldom reported, because the diffusion of the dopant counterions often leads to transient rectification properties. Herein, a new type of lateral fully organic diodes created in single donor-acceptor (D-A) copolymer films with only one P-type dopant is reported. The achieved lateral devices exhibit high current densities of approximate to 3.83 A cm(-2) and a high rectification ratio of approximate to 2100, which are beyond the requirements for high-frequency identification tags. The P- to N-type polarity switching mechanism is proposed after spectroscopic and structural tests. Decent stability of the organic diode is obtained, which is due to the long channel length and low diffusion speed of the large size of dopants. This work opens the opportunities to create P-N junctions in ways of silicon-based inorganic semiconductors and promises new opportunities for integrating organic materials for flexible and printable organic devices.

关键词： donor-acceptor copolymers fully organic diodes lateral structure polarity switching single materials

来源：评论

学校读者我要写书评

暂无评论

Hydrothermal molten salt: A hydrothermal fluid in SCWO treatment of hypersaline wastewater

引用

CHEMICAL engineering JOURNAL 2021年 421卷

作者： Zhang, Yishu Wang, Shuzhong Gao, Ziliang Li, Yanhui Xu, Tiantian Li, Jianna Xu, Donghai Yang, Jianqiao Xi An Jiao Tong Univ Key Lab Thermofluid Sci & Engn MOE Sch Energy & Power Engn 28 Xianning West Rd Xian 710049 Shaanxi Peoples R China Xi An Jiao Tong Univ State Key Lab Multiphase Flow Power Engn 28 Xianning West Rd Xian 710049 Shaanxi Peoples R China

A hydrothermal fluid system proposed in this paper is composed of immiscible molten salts and sub-/supercritical water (also named as hydrothermal molten salt, HyMoS). It can avoid salt deposition and equipment blocking in the process of SCWO treatment of hypersaline glyphosate wastewater, which provides an exalting technical idea for preventing and controlling salt deposition occurred in various fields of thermophysics and thermochemistry. Aiming to understand the behavior characteristics and rules of multiple salts in SCWO process and explain the formation mechanism of HyMoS, the main salt constituents (NaCl and Na2HPO4) in glyphosate wastewater were taken as research objects. XJTU - SCWO continuous pilot plant was used to systematically investigate their dissolution, transportation and deposition characteristics during SCWO. The phase equilibrium rules and melt properties of them in sub-/supercritical water was acquired via on-line record and observation on the Visual phase equilibrium apparatus. The result verified the inhibition effect of low-melting salts on salt crystallization and deposition, obtained the behavior characteristics of NaCl, Na2HPO4 and their mixtures, and established the mechanism model of salt melting and redissolving in sub-/supercritical water during temperature rising and dropping, respectively. Furthermore, the dissolution-melt-crystallization phase diagram of Na2HPO4 in sub-/supercritical water was established for the first time.

关键词： Supercritical water oxidation Salt deposition Hydrothermal molten salt Visual phase equilibrium Transportation characteristics Melting properties

来源：评论

学校读者我要写书评

暂无评论

Effects of ashing method and blending on ash characteristics of pyrolyzed and gasified semi-cokes

引用

FUEL 2020年 271卷

作者： Wang, Chang'an Zhao, Lin Yuan, Maobo Liu, Chengchang Wang, Chaowei Zhao, Lei Wang, Pengqian Che, Defu Xi An Jiao Tong Univ Sch Energy & Power Engn State Key Lab Multiphase Flow Power Engn Xian 710049 Peoples R China

The characterization of ash properties is of benefit for better elucidating the ash-related issues during utilization of semi-coke. Nevertheless, the impact of different ashing methods on ash characteristics of semi-coke still remains unclear, along with the influence of blending various semi-cokes. In the present study, the ashes of pyrolyzed and gasified semi-cokes were prepared from two different methods, low-temperature plasma ashing at <200 degrees C and traditional muffle ashing at 815 degrees C to investigate the effects of ashing method on ash characteristics of semi-coke, which has been seldom conducted before. The low-temperature plasma oxidization could consume organic matter without destroying the initial state of mineral species in semi-coke matrix. A variety of analysis techniques including X-ray fluorescence (XRF), X-ray diffraction (XRD) and thermal analysis was performed to study ash composition, mineral phase, thermal volatility, and so on. The results show that the appearance and yield of low-temperature ash (LTA) and high-temperature ash (HTA) are highly related to the ashing approach and the category of semi-cokes. The mass fractions of most oxides contained in LTA are lower than those in HTA. The main difference of mineral phases between LTA and HTA of semi-cokes lies in the existence form of calcium. The ashing method exerts remarkable influences on thermal behaviors of pyrolyzed semi-coke ash but insignificant effect on those of gasified semi-coke. Moreover, the effects of blending pyrolyzed and gasified semi-cokes on the ash compositions and thermal behaviors are significant, while the mineral phases seem to be independent of the blending process.

关键词： Physical-chemical characteristics Pyrolyzed semi-coke Gasified semi-coke Blending Ashing method Low-temperature plasma

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：