检索结果-内蒙古大学图书馆

Rapid removal of ammonia nitrogen in low-concentration from wastewater by amorphous sodium titanate nano-particles

SCIENCE OF THE TOTAL ENVIRONMENT 2019年 668卷 815-824页

作者： Zhang, Wenlong Fu, Rao Wang, Li Zhu, Jinwei Feng, Jiangtao Yan, Wei Xi An Jiao Tong Univ Sch Energy & Power Engn State Key Lab Multiphase Flow Power Engn Dept Environm Sci & Engn Xian 710049 Peoples R China Shaanxi Elect Equipment Inst Xian 710025 Shaanxi Peoples R China

An amorphous sodium titanate (ST) nano-particle was prepared via the facile hydrolytic process with the addition of sodium hydroxide and firstly used for ammonia nitrogen (NH3-N) removal from wastewater. ST exhibited satisfactory adsorption efficiency for NH3-N simulative wastewater (20 mg.L-1) at a wide range of pH 3.0-9.0, within a minimum contact time of 10 min. The Langmuir isotherm showed that the maximum adsorption capacity (298 K) of the adsorbent was reach up to 44.54 mg.g(-1). Concentrated competing cations had some interferences with NH3-N adsorption at the order of Ca2+ > K+ > Mg2+ > Na+ according to their competition on adsorption sites. During the adsorption process, cation exchange between Na+ and NH4+ played a powerful role for the NH3-N removal and the contribution of Ti-OH groups was also involved in the adsorption. The regeneration test showed that the saturated adsorbents could be conveniently regenerated just by NaOH or NaCl solution treatment and there was no obvious decline of the adsorption capacity after reused for five times. The facile method of fabrication and regeneration, the rapid adsorption process and the satisfactory adsorption efficiency make sodium titanate a promising adsorbent for low concentration NH3-N minimization. (C) 2019 Elsevier B.V. All rights reserved.

关键词： Ammonia nitrogen Sodium titanate Rapid adsorption Cation exchange Wastewater treatment

来源：评论

学校读者我要写书评

暂无评论

Numerical research on thermal mixing characteristics in a 45-degree T-junction for two-phase stratified flow during the emergency core cooling safety injection

引用

PROGRESS IN NUCLEAR ENERGY 2019年 114卷 91-104页

作者： Feng, Tangtao Wang, Mingjun Song, Ping Liu, Luguo Tian, Wenxi Su, G. H. Qiu, Suizheng Xi An Jiao Tong Univ Sch Nucl Sci & Technol State Key Lab Multiphase Flow Power Engn Shaanxi Key Lab Adv Nucl Energy & Technol Xian 710049 Peoples R China Nucl Power Inst China Sci & Technol Reactor Syst Design Technol Lab Chengdu 610041 Peoples R China

The thermal mixing and direct contact condensation are the most significant phenomena appeared during the Emergency Core Cooling (ECC) system safety injection process. The three-dimensional thermal mixing characteristics accompanied by complicated direct contact condensation are investigated using CFD method. Firstly, the feasibility of two-phase CFD models are validated by the experimental data obtained from the XJTU-ECC experimental apparatus. Results show that the established CFD models could predict the two-phase mixing process correctly and the errors between numerical results and experimental data are smaller than 30%. Then the two-phase thermal mixing features, including temperature fields, velocity fields and volume fraction, are achieved in detail. Moreover, the local steam condensation characteristics are studied carefully and results show that the condensation rate is proved closely related to the coolant thermodynamic ratio between the main pipe and branch pipe. Finally, an empirical correlation is proposed to predict the condensation rate in case that the thermodynamic ratio is lower than 0.55. This work provides a fundamental guideline for the ECC system structure optimization and fatigue aging in the advanced nuclear power plants.

关键词： Two-phase stratified flow ECC Thermal mixing Condensation rate

来源：评论

学校读者我要写书评

暂无评论

Effects of nitrogen and carbon monoxide on the detonation of hydrogen-air gaseous mixtures

引用

NUCLEAR engineering AND DESIGN 2019年 343卷 1-10页

作者： Chen, Yongzheng Liu, Bo Zhang, Y. P. Zhang, D. L. Revankar, Shripad T. Tian, W. X. Qiu, S. Z. Su, G. H. Xi An Jiao Tong Univ State Key Lab Multiphase Flow Power Engn Dept Nucl Sci & Technol Xian 710049 Peoples R China Purdue Univ Sch Nucl Engn W Lafayette IN 47907 USA

Nitrogen inhibition is considered as a mitigation measure against chemically sensitive mixtures in industry and carbon monoxide is possibly generated during molten corium concrete interaction in a severe accident of nuclear power plants. To study the effects of the N-2 and CO on the detonation of H-2-air mixtures, a detonation facility of 78 mm inner diameter and 10 m length is set up. key measured parameters includes detonation cell size, flame velocity, lean and rich detonation limits. All the measured detonation parameters are theoretically predicted by CJ theory or one-dimensional ZND model. Detailed chemical kinetics mechanism for H-2-air and H-2-CO-air mixtures is coupled with reactive Euler equations. Experiments and theoretically analysis has been performed mostly at 0.101 MPa and 293 K. Results shows that N-2 increases the detonation cell size and narrows down the detonable range significantly. Especially when N-2 concentration is more than 43%, all mixtures are unable to detonate. Moreover, when the added N-2 concentration is larger than 20%, detonation velocity does not increase with hydrogen concentration for rich mixtures. The above effects of N-2 is explained by the replacement of O-2 with N-2 and by the weak chemical reaction of N-2. CO significantly decreases the cell size of lean H-2-air mixtures and increased the cell size for rich H-2 -air mixtures. For lean H-2-air mixtures, the added CO linearly decreases the lean detonation limit, thus increasing the possibility of detonation to occur in the severe accidents. Therefore, the contribution of CO must be carefully considered in the safety assessment. Results also shows that pure CO is difficult to detonate in the air, while small quantity of hydrogen can significantly enhance the rate of CO oxidation reactions.

关键词： Severe accident Hydrogen detonation Nitrogen inhibition effect Carbon monoxide

来源：评论

学校读者我要写书评

暂无评论

Heat transfer of supercritical endothermic fuel in 3-mm diameter channels: Comparison between asymmetric and uniform heating

引用

INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER 2019年 140卷 371-378页

作者： Liu, Zhaohui Zhang, Zanjian Zhao, Shujun Pan, Hui Bi, Qincheng Xi An Jiao Tong Univ State Key Lab Multiphase Flow Power Engn Xian 710049 Shaanxi Peoples R China 31st Res Inst CASIC Sci & Technol Scramjet Lab Beijing 10074 Peoples R China

In the study, a novel conductive and asymmetric heating (AH)(1) test section was built to simulate a regenerative cooling passage in the scramjet combustor wall. A test channel with an external diameter of 4.0 mm and a wall thickness of 0.5 mm was conductively heated by a semicircle heating element, and this was electrically heated with zirconia coating as an electrical insulator. Heat transfer characteristics of endothermic fuel in the AH test section were compared with those in the uniform heating (UH)(2) test section at a super-critical pressure of 3.0 MPa, fluid temperatures of up to 600 degrees C, and mass flow rates of 0.5, 1.0, and 1.5 g/s (71, 142, and 212 kg/m(2)s). The results indicated that the absorbed heat flux reached a maximum value of 272 kW/m(2) with a surface temperature of asymmetric heating element approaching 800 degrees C, and it significantly decreased when the fluid temperature increased. When compared with UH, the AH exhibited a lower heating efficiency of always less than 50% owing to the higher heat loss caused by higher surface temperature of the heating element. However, the heating efficiency in AH exceeded that in the UH at fluid temperature exceeding pseudo-critical point. The heat transfer characteristics of endothermic fuel were barely affected by the elevated different mass flow rates due to the mitigation of the refractory coating in the AH test section. However, the general heat transfer trends of endothermic fuel were obtained between AH and UH including a decrease in the heat transfer approximately at the pseudo-critical point, heat transfer enhancement at sub-cooled boiling conditions, and surface temperature profile of test channel at different mass flow rates. (C) 2019 Elsevier Ltd. All rights reserved.

关键词： Asymmetric heating Endothermic fuel Heat transfer Regenerative cooling Scramjet

来源：评论

学校读者我要写书评

暂无评论

Theoretical Study on Cryogen Spray Cooling in Laser Treatment of Ota's Nevus: Comparison and Optimization of R134a, R404A and R32

引用

ENERGIES 2020年第21期13卷 5647页

作者： Tian, Jiameng Chen, Bin Zhou, Zhifu Li, Dong Xi An Jiao Tong Univ State Key Lab Multiphase Flow Power Engn Xian 710049 Peoples R China Jiangsu Univ Sch Energy & Power Engn Zhenjiang 212013 Jiangsu Peoples R China

Cryogen spray cooling (CSC) could be applied clinically for the laser therapy of Ota's nevus, a dermal hyperplastic pigmented disease with a morbidity rate of 0.1-0.6% in the Asian population. An accurate, efficient, complete simulation system that considers the entire spray cooling process, including cryogen flow in the tube nozzle, spray dynamics and internal phase change heat transfer (cold injury) in skin tissue, was established to determine suitable cryogen and cooling parameters. The optimum spray distances for R134a, R404A and R32 were determined to be 66.0, 43.1 and 22.5 mm, respectively. The corresponding maximum surface heat fluxes were 363.5, 459.9, and 603.6 kW center dot m(-2), respectively. The maximum surface heat flux of R32 with small spray distance was 1.66 times as large as that of R134a, indicating the potentially good cooling performance and precise targeted cooling of R32 during the laser therapy of Ota's nevus. The cooling durations that caused cold injury of skin tissue were 2.3, 1.4, and 1.1 s for R134a, R404A, and R32, respectively. The interval between CSC and laser irradiation was optimized to 90-162 ms for R134a, R404A and R32, in consideration of the cooling effect, depth, uniformity, and risk of cold injury.

关键词： cryogen spray cooling nevus of Ota laser therapy cold injury bio-heat transfer

来源：评论

学校读者我要写书评

暂无评论

Design and optimization of waste heat recovery system for supercritical carbon dioxide coal-fired power plant to enhance the dust collection efficiency

引用

JOURNAL OF CLEANER PRODUCTION 2020年 275卷 122523-122523页

作者： Liu, Ming Yang, Kaixuan Zhang, Xuwei Yan, Junjie Xi An Jiao Tong Univ State Key Lab Multiphase Flow Power Engn Xian 710049 Peoples R China Xian Thermal Power Res Inst Co Ltd Xian 710054 Peoples R China

The supercritical carbon dioxide (SCO2) power cycle is a potential power cycle for coal-fired power plants. In the SCO2 power systems provided in previous studies, the boiler exhaust temperature is about 120 degrees C. To enhance the power plant efficiency and the dust collection efficiency of electrostatic precipitator, SCO2 power systems should be advanced to cool the boiler exhaust fluegas to nearly 95 degrees C. Therefore, systems of waste heat recovery from low-temperature fluegas are proposed and optimized in this study. Thermodynamic and optimization models are developed. The double reheat recompression SCO2 cycle is optimized as benchmark system. The benchmark system is improved to decrease the exergy loss and boiler exhaust, decrease the irreversibility of air preheater, and recover waste heat of the SCO2 cycle to preheat air to the air preheater. When the main compressor intercooling or bypass fluegas ahead the air preheater is adopted, the temperature of boiler exhaust fluegas can be decreased to around 95 degrees C which can ensure a high dust collection efficiency of electrostatic precipitator. The power plant efficiency is also increased as a result. However, if only low-temperature economizer is integrated, then the power plant efficiency is enhanced slightly by 0.09%-pts. If the low temperature economizer is integrated with other system improvements, the power plant efficiency can be enhanced by 0.89%-pts. Exergy analysis is also performed to reveal the mechanisms of efficiency enhancement. (C) 2020 Elsevier Ltd. All rights reserved.

关键词： Coal power SCO2 cycle Waste heat recovery Optimization Thermodynamics Genetic Algorithm

来源：评论

学校读者我要写书评

暂无评论

One-dimensional drift-flux correlation for vertical upward two-phase flow in large size concentric and eccentric annuli

引用

INTERNATIONAL JOURNAL OF multiphase flow 2019年第0期113卷 33-44页

作者： Zhao, Quanbin Hibiki, Takashi Xi An Jiao Tong Univ State Key Lab Multiphase Flow Power Engn Xian 710049 Shaanxi Peoples R China Purdue Univ Sch Nucl Engn 400 Cent Dr W Lafayette IN 47907 USA

In view of the practical importance of predicting void fraction in two-phase flow, a correlation based on the drift-flux model is often utilized in many industrial fields. To use the drift-flux type correlation, two drift-flux parameters such as distribution parameter and void fraction weighted mean drift velocity should be modeled accurately. Since the drift-flux parameters are susceptible to channel size, they are modeled differently depending on whether the channel size is characterized as small (or mini), medium or large. Although drift-flux type correlations with modeled distribution parameter and drift velocity for medium size channels with various geometries have been well-developed, limited drift-flux correlations are available for large size channels. Two-phase flow characteristics in a large size channel are quite different from those in a medium size channel at low flow conditions. Large slug bubbles observed in a medium size channel do not form in a large size channel due to the presence of surface instability. As large slug bubbles disintegrate into smaller cap bubbles, the drift velocity is increased. Complex two-phase flow characteristics in a large size channel also affect the distribution parameter. This study successfully models the distribution parameter and drift velocity for two-phase flow in a vertical concentric annulus. The drift-flux correlation with modeled distribution parameter and drift velocity is validated by existing data taken in large size annuli. The applicability of the drift-flux correlation to two-phase flow in a vertical eccentric annulus is also examined by existing data. (C) 2018 Elsevier Ltd. All rights reserved.

关键词： Drift-flux model Void fraction Holdup Large annulus Two-phase flow

来源：评论

学校读者我要写书评

暂无评论

Intercomparison of NO3 under Humid Conditions with Open-Path and Extractive IBBCEAS in an Atmospheric Reaction Chamber

引用

REMOTE SENSING 2023年第3期15卷 739页

作者： Wang, Meng Lou, Shengrong Hu, Weiwei Wang, Haichao Wang, Xinming Fan, Fengxian Varma, Ravi Venables, Dean S. S. Chen, Jun Univ Shanghai Sci & Technol Sch Energy & Power Engn Shanghai Key Lab Multiphase Flow & Heat Transfer P Shanghai 200093 Peoples R China Shanghai Acad Environm Sci State Environm Protect Key Lab Format & Prevent Ur Shanghai 200233 Peoples R China Guangzhou Inst Geochem Chinese Acad Sci State Key Lab Organ Geochem Guangzhou 510640 Peoples R China Chinese Acad Sci Guangdong Prov Key Lab Environm Protect & Resource Guangzhou 510640 Peoples R China Sun Yat sen Univ Sch Atmospher Sci Guangzhou 510275 Peoples R China Minist Educ Key Lab Trop Atmosphere Ocean Syst Southern Marine Sci & Engn Guangdong Lab Zhuhai Guangdong Prov Observat & Res Stn Climate Environm Zhuhai 519082 Peoples R China Natl Inst Technol Calicut Dept Phys Calicut 673601 India Univ Coll Cork Sch Chem Cork T12 YN60 Ireland Univ Coll Cork Environm Res Inst Cork T12 YN60 Ireland

We report an open-path incoherent broadband cavity-enhanced absorption spectroscopy (OP-IBBCEAS) technique for in situ simultaneous optical monitoring of NO2, NO3, and H2O in a reaction chamber. The measurement precision values (1 sigma) are 2.9 ppbv and 2.9 pptv for NO2 and NO3 in 2 s, respectively, and the measurement uncertainties are 6% for NO2 and 14% for NO3. Intercomparison of measured concentrations of NO2 and NO3 by open-path and extractive IBBCEAS was carried out in the SAES-ARC reaction chamber during the reaction of NO2 with O-3. The measurement accuracy of OP-IBBCEAS is verified by an NO2 intercomparison and the NO3 transmission efficiency of the extractive IBBCEAS is determined by comparison against the in situ NO3 measurement. The relationship between H2O absorption cross section and its mixing ratio at 295 K and 1 atm was analysed. Due to the spectral resolution of IBBCEAS system, the strong and narrow absorption lines of H2O are unresolved and exhibit non-Beer-Lambert Law behaviour. Therefore, a correction method is used to obtain the effective absorption cross section for fitting the H2O structure. An inappropriate H2O absorption cross section can cause an overestimation of NO3 concentration of about 28% in a humid atmosphere (H2O = 1.8%). This spectroscopic correction provides an approach to obtain accurate NO3 concentrations for open-path optical configurations, for example in chamber experiments or field campaigns. The measurement precision values are improved by a factor of 3 to 4 after applying Kalam filtering, achieving sub-ppbv (0.8 ppbv) and sub-pptv (0.9 pptv) performance in 2 s for NO2 and NO3, respectively.

关键词： spectroscopy open-path IBBCEAS trace pollutant detection nitrate radical

来源：评论

学校读者我要写书评

暂无评论

CFD and FEM combined study on the solid particle erosion damage of multi-stage compressor blades

引用

Powder Technology 2025年

作者： Hongkun Zhan Yanfang Hou Liuxi Cai Jiaming He Yun Li Shunsen Wang Juan Di School of Chemical Engineering and Technology Xi'an Jiaotong University Xi'an 710049 PR China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an 710049 PR China School of Vehicle and Traffic Engineering Taiyuan University of Science and Technology Taiyuan 030024 PR China

Dust and sand particles in the air can cause serious erosion damage to the titanium alloy blades of the compressor, significantly reducing the working life of the engine. To study the erosion mechanism of solid particles on multi-stage compressor blades in detail, first, CFD gas-solid two-phase flow numerical simulation method is employed to study the motion and impact behavior of quartz sand particles in the compressor flow channel, which clarify the macroscopic mechanism of particle erosion damage on the blades and determine the particle impact parameters. Then, the microscopic erosion damage mechanism of titanium alloy blades is studied through an improved FEM method. Considering the characteristics of multiple particle impingement, random particle shape, random impingement position, and repetitive erosion process during the impact process, a three-dimensional multi-particle random cyclic impact finite element calculation model is established for the first time. On the basis, coupled analysis of the characteristics of material microdamage morphology, system energy conversion and dissipation, and target material erosion weight loss is conducted to reveal the dynamic erosion damage mechanism of multi-particle impacting titanium alloys. Finally, the influences of factors such as the impact velocity, impact angle, and particle shape on the dynamic erosion damage behavior of titanium alloy targets were explored.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Rational fabrication flowerlike BiOBr with oxygen vacancy for enhancing photocatalytic performance to remove gaseous mercury

引用

CHEMICAL PHYSICS LETTERS 2021年 785卷 139164-139164页

作者： Zhang, Zhaopeng Li, Shuai Guan, Yu Jia, Tao Zhang, Meilin Liu, Qizhen Qi, Yongfeng Wu, Jiang Liu, Guolong Xie, Xialin Shanghai Univ Elect Power Coll Energy & Mech Engn Shanghai 200090 Peoples R China Xi An Jiao Tong Univ State Key Lab Multiphase Flow Power Engn Sch Energy & Power Engn Xian 710049 Peoples R China Tongji Univ Coll Environm Sci & Engn State Key Lab Pollut Control & Resources Reuse Shanghai 200092 Peoples R China Shanghai Environm Monitoring Ctr Shanghai 200030 Peoples R China Yangzhou Univ Sch Hydraul Energy & Power Engn Yangzhou 225127 Jiangsu Peoples R China

In this work, the different morphologies of BiOBr photocatalyst were successfully synthesized by mixing method, hydrothermal method, and calcination method for gas-phase Hg-0 photocatalytic oxidation. The physicochemical properties of the BiOBr were characterized by XRD, SEM, TEM analysis etc. It was found that all BiOBr photocatalyst samples showed excellent ability photocatalytic oxidation of Hg-0 under visible light irradiation, and the BiOBr-C sample prepared by calcination method showed the highest mercury removal efficiency about 60.5% among all samples. This can be attributed to the morphology of flowerlike BiOBr-C can enhance the electron transfer ability in three-dimensional space. Besides, the calcination method is beneficial to enhance the formation of oxygen vacancy and the introduction of oxygen vacancies can efficiently improve the ability of electron capture, and further promote the photocatalytic performance of BiOBr-C. Finally, a possible photocatalytic reaction mechanism was proposed.

关键词： Oxygen vacancy Oxidation Internal electric field flowerlike BiOBr photocatalyst Mercury

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：