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simulated flue gas using aqueous persulfate with activation of ferrous ethylenediaminetetraacetate in the rotatingpacked bed

《化学科学与工程前沿(英文)》 2023年 第17卷 第4期   页码 460-469 doi: 10.1007/s11705-022-2224-5

摘要: Nitric oxide being a major gas pollutant has attracted much attention and various technologies have been developed to reduce NO emission to preserve the environment. Advanced persulfate oxidation technology is a workable and effective choice for wet flue gas denitrification due to its high efficiency and green advantages. However, NO absorption rate is limited and affected by mass transfer limitation of NO and aqueous persulfate in traditional reactors. In this study, a rotating packed bed (RPB) was employed as a gas–liquid absorption device to elevate the NO removal efficiency (ηNO) by aqueous persulfate ((NH4)2S2O8) activated by ferrous ethylenediaminetetraacetate (Fe2+-EDTA). The experimental results regarding the NO absorption were obtained by investigating the effect of various operating parameters on the removal efficiency of NO in RPB. Increasing the concentration of (NH4)2S2O8 and liquid–gas ratio could promoted the oxidation and absorption of NO while the ηNO decreased with the increase of the gas flow and NO concentration. In addition, improving the high gravity factor increased the ηNO and the total volumetric mass transfer coefficient (KGα) which raise the ηNO up to more than 75% under the investigated system. These observations proved that the RPB can enhance the gas–liquid mass transfer process in NO absorption. The correlation formula between KGα and the influencing factors was determined by regression calculation, which is used to guide the industrial scale-up application of the system in NO removal. The presence of O2 also had a negative effect on the NO removal process and through electron spin resonance spectrometer detection and product analysis, it was revealed that Fe2+-EDTA activated (NH4)2S2O8 to produce •SO4, •OH and •O2, played a leading role in the oxidation of NO, to produce NO3 as the final product. The obtained results demonstrated a good applicable potential of RPB/PS/Fe2+-EDTA in the removal of NO from flue gases.

关键词: rotating packed bed     Fe2+-EDTA     sulfate radical     hydroxyl radical     NO removal efficiency    

High-gravity intensified iron-carbon micro-electrolysis for degradation of dinitrotoluene

《化学科学与工程前沿(英文)》 2023年 第17卷 第10期   页码 1595-1605 doi: 10.1007/s11705-022-2204-9

摘要: The application of iron–carbon (Fe–C) micro-electrolysis to wastewater treatment is limited by the passivation potential of the Fe–C packing. In order to address this problem, high-gravity intensified Fe–C micro-electrolysis was proposed in this study for degradation of dinitrotoluene wastewater in a rotating packed bed (RPB) using commercial Fe–C particles as the packing. The effects of reaction time, high-gravity factor, liquid flow rate and initial solution pH were investigated. The degradation intermediates were determined by gas chromatography-mass spectrometry, and the possible degradation pathways of nitro compounds by Fe–C micro-electrolysis in RPB were also proposed. It is found that under optimal conditions, the removal rate of nitro compounds reaches 68.4% at 100 min. The removal rate is maintained at approximately 68% after 4 cycles in RPB, but it is decreased substantially from 57.9% to 36.8% in a stirred tank reactor. This is because RPB can increase the specific surface area and the renewal of the liquid–solid interface, and as a result the degradation efficiency of Fe–C micro-electrolysis is improved and the active sites on the Fe–C surface can be regenerated for continuous use. In conclusion, high-gravity intensified Fe–C micro-electrolysis can weaken the passivation of Fe–C particles and extend their service life.

关键词: high-gravity technology     rotating packed bed     Fe–C micro-electrolysis     dinitrotoluene wastewater     active sites    

Preparation of transparent BaSO

Le Fang, Qian Sun, Yong-Hong Duan, Jing Zhai, Dan Wang, Jie-Xin Wang

《化学科学与工程前沿(英文)》 2021年 第15卷 第4期   页码 902-912 doi: 10.1007/s11705-020-1985-y

摘要: BaSO nanoparticles as important functional materials have attracted considerable research interests, due to their X-rays barrier and absorption properties. However, most of BaSO nanoparticles prepared by traditional technology are nanopowders with broad size distribution and poor dispersibility, which may greatly limit their applications. To the best of our knowledge, the synthesis of transparent BaSO nanodispersions was rarely reported. Here, we firstly present a novel and efficient method to prepare transparent and stable BaSO nanodispersions with a relatively small particle size around 10 to 17 nm using a precipitation method in a rotating packed bed (RPB), followed by a modification treatment using stearic acid. Compared with the BaSO prepared in a traditional stirred tank, the product prepared using an RPB has much smaller particle size and narrower size distribution. More importantly, by using RPB, the reaction time can be significantly decreased from 20 min to 18 s. Furthermore, the transparent BaSO -polyvinyl butyral nanocomposite films with good X-ray shielding performance can be easily fabricated. We believe that the stable BaSO nanodispersions may have a wide range of applications for transparent composite materials and coatings with X-ray shielding performance for future research.

关键词: BaSO4 nanoparticles     rotating packed bed     transparent nanodispersions     BaSO4-PVB films     X-ray shielding    

Thermal performance of a single-layer packed metal pebble-bed exposed to high energy fluxes

Shengchun ZHANG, Zhifeng WANG, Hui BIAN, Pingrui HUANG

《能源前沿(英文)》 2021年 第15卷 第2期   页码 513-528 doi: 10.1007/s11708-019-0638-7

摘要: It is difficult to accurately measure the temperature of the falling particle receiver since thermocouples may directly be exposed to the solar flux. This study analyzes the thermal performance of a packed bed receiver using large metal spheres to minimize the measurement error of particle temperature with the sphere temperature reaching more than 700°C in experiments in a solar furnace and a solar simulator. The numerical models of a single sphere and multiple spheres are verified by the experiments. The multiple spheres model includes calculations of the external incidence, view factors, and heat transfer. The effects of parameters on the temperature variations of the spheres, the transient thermal efficiency, and the temperature uniformity are investigated, such as the ambient temperature, particle thermal conductivity, energy flux, sphere diameter, and sphere emissivity. When the convection is not considered, the results show that the sphere emissivity has a significant influence on the transient thermal efficiency and that the temperature uniformity is strongly affected by the energy flux, sphere diameter, and sphere emissivity. As the emissivity increases from 0.5 to 0.9, the transient thermal efficiency and the average temperature variance increase from 53.5% to 75.7% and from 14.3% to 27.1% at 3.9 min, respectively. The average temperature variance decreases from 29.7% to 9.3% at 2.2 min with the sphere diameter increasing from 28.57 mm to 50 mm. As the dimensionless energy flux increases from 0.8 to 1.2, the average temperature variance increases from 13.4% to 26.6% at 3.4 min.

关键词: packed bed     solar thermal power plants     high heat fluxes     radiative heat transfer    

Abatement of mixed volatile organic compounds in a catalytic hybrid surface/packed-bed discharge plasma

Lianjie Guo, Nan Jiang, Jie Li, Kefeng Shang, Na Lu, Yan Wu

《环境科学与工程前沿(英文)》 2018年 第12卷 第2期 doi: 10.1007/s11783-018-1017-z

摘要: In this study, post plasma-catalysis degradation of mixed volatile organic compounds (benzene, toluene, and xylene) has been performed in a hybrid surface/packed-bed discharge plasma reactor with Ag-Ce/ g-Al O catalyst at room temperature. The effect of relative air humidity on mixed VOCs degradation has also been investigated in both plasma-only and PPC systems. In comparison to the plasma-only system, a significant improvement can be observed in the degradation performance of mixed VOCs in PPC system with Ag-Ce/ g-Al O catalyst. In PPC system, 68% benzene, 89% toluene, and 94% xylene were degraded at 800 J·L , respectively, which were 25%, 11%, and 9% higher than those in plasma-only system. This result can be attributed to the high catalytic activity of Ag-Ce/ g-Al O catalyst to effectively decompose O and lead to generating more reactive species which are capable of destructing the VOCs molecules completely. Moreover, the presence of Ag-Ce/ g-Al O catalyst in plasma significantly decreased the emission of discharge byproducts (NO and O ) and promoted the mineralization of mixed VOCs towards CO . Adding a small amount of water vapor into PPC system enhanced the degradation efficiencies of mixed VOCs, however, further increasing water vapor had a negative impact on the degradation efficiencies, which was primarily attributed to the quenching of energetic electrons by water vapor in plasma and the competitive adsorption of water vapor on the catalyst surface. Meanwhile, the catalysts before and after discharge were characterized by the Brunauer-Emment-Teller and X-ray photoelectron spectroscopy.

关键词: Mixed VOCs     HSPBD plasma reactor     Degradation     Catalyst     Relative humidity    

Large-scale industrial manufacturing of carbon nanotubes in a continuous inclined mobile-bed rotating

Sophie L. Pirard, Sigrid Douven, Jean-Paul Pirard

《化学科学与工程前沿(英文)》 2017年 第11卷 第2期   页码 280-289 doi: 10.1007/s11705-017-1635-1

摘要: This article reports the different steps of the design, development and validation of a process for continuous production of carbon nanotubes (CNTs) via catalytic chemical vapor deposition from the laboratory scale to the industrial production. This process is based on a continuous inclined mobile-bed rotating reactor and very active catalysts using methane or ethylene as carbon source. The importance of modeling taking into account the hydrodynamic, physicochemical and physical phenomena that occur during CNT production in the process analysis is emphasized. The impact of this invention on the environment and human health is taken into consideration too.

关键词: carbon nanotubes     catalytic chemical vapor deposition     inclined rotating reactor     industrial process     scaling-up    

堆积床相变储热系统中径向孔隙率振荡分布对热性能的影响 Article

刘红兵, 赵长颖

《工程(英文)》 2021年 第7卷 第4期   页码 515-525 doi: 10.1016/j.eng.2020.05.020

摘要:

由于具有较高的储热能力和传热速率,堆积床相变储热被认为是一种很有潜力的储热方法。在堆积床中,壁面效应会影响相变胶囊的填充结构,从而引起径向孔隙率的振荡。本研究建立了一个基于球体实际堆积过程的三维堆积床相变储热模型,以描述径向孔隙率的振荡分布,并分析了其内部的流动和传热情况。通过在堆积床中沿径向不同位置截取圆柱面,揭示了相变胶囊的排列与径向孔隙率之间的对应关系。径向孔隙率的振荡分布导致换热流体速度呈不均匀分布,因此相变材料的径向温度分布和液相分数分布进一步受到影响。此外,本文讨论了不同的无量纲参数(如管与胶囊的直径比、雷诺数和史蒂芬数)对换热流体和相变材料径向特性的影响。结果表明,不同的直径比对应于不同的径向孔隙率分布。此外,随着直径比的增加,在壁面附近区域换热流体速度显著变化,而中心区域换热流体速度的不均匀性将减小。雷诺数和史蒂芬数对换热流体的相对速度分布有轻微影响,而更高的雷诺数可导致速度成比例地提高,史蒂芬数的增加可加快堆积床相变储热系统的储热过程。

关键词: 堆积床相变储热     径向孔隙率振荡     流动换热     传热强化     直径比    

Simultaneous CO

Jie ZHU,Wei WANG,Xiuning HUA,Zhou XIA,Zhou DENG

《环境科学与工程前沿(英文)》 2015年 第9卷 第6期   页码 1117-1129 doi: 10.1007/s11783-015-0812-z

摘要: The chemical looping concept provided a novel way to achieve carbon separation during the production of energy or substances. In this work, hydrogen generation with inherent CO capture in single packed bed reactor via this concept was discussed. Two oxygen carriers, Fe O 60 wt.% and Fe O 55 wt.%/CuO 5 wt.% supported by Al O , were made by ball milling method. First, according to the characteristics of the reduction breakthrough curve, a strict fuel supply strategy was selected to achieve simultaneous CO capture and H production. Then, in the long term tests using CO as fuel, it was proved that CuO addition improved hydrogen generation with the maximum intensity of 3700 μmol H ·g Fe O compared with Fe-Al of 2300 μmol H ·g Fe O . The overall CO capture efficiency remained 98%–98.8% over 100 cycles. Moreover, the reactivity of deactivated materials was recovered nearly like that of fresh ones by sintering treatment. Finally, two kinds of complex gases consist of CO, H , CH and CO were utilized as fuels to test the feasibility. The results showed all components could be completely converted by Fe-Cu-Al in the reduction stage. The intensity of hydrogen production and the overall CO capture efficiency were in the range of 2000–2400 μmol H ·g Fe O and 89%–95%, respectively.

关键词: CO2 capture     chemical looping hydrogen generation     iron based oxygen carriers     single packed bed reactor     long-term test     complex gases fuel    

Nonlinear dynamic behavior of rotating blade with breathing crack

Laihao YANG, Zhu MAO, Shuming WU, Xuefeng CHEN, Ruqiang YAN

《机械工程前沿(英文)》 2021年 第16卷 第1期   页码 196-220 doi: 10.1007/s11465-020-0609-z

摘要: This study aims at investigating the nonlinear dynamic behavior of rotating blade with transverse crack. A novel nonlinear rotating cracked blade model (NRCBM), which contains the spinning softening, centrifugal stiffening, Coriolis force, and crack closing effects, is developed based on continuous beam theory and strain energy release rate method. The rotating blade is considered as a cantilever beam fixed on the rigid hub with high rotating speed, and the crack is deemed to be open and close continuously in a trigonometric function way with the blade vibration. It is verified by the comparison with a finite element-based contact crack model and bilinear model that the proposed NRCBM can well capture the dynamic characteristics of the rotating blade with breathing crack. The dynamic behavior of rotating cracked blade is then investigated with NRCBM, and the nonlinear damage indicator (NDI) is introduced to characterize the nonlinearity caused by blade crack. The results show that NDI is a distinguishable indicator for the severity level estimation of the crack in rotating blade. It is found that severe crack (i.e., a closer crack position to blade root as well as larger crack depth) is expected to heavily reduce the stiffness of rotating blade and apparently result in a lower resonant frequency. Meanwhile, the super-harmonic resonances are verified to be distinguishable indicators for diagnosing the crack existence, and the third-order super-harmonic resonances can serve as an indicator for the presence of severe crack since it only distinctly appears when the crack is severe.

关键词: rotating blade     breathing crack     nonlinear vibration     nonlinear damage indicator    

New method of fault diagnosis of rotating machinery based on distance of information entropy

Houjun SU, Tielin SHI, Fei CHEN, Shuhong HUANG

《机械工程前沿(英文)》 2011年 第6卷 第2期   页码 249-253 doi: 10.1007/s11465-011-0124-3

摘要:

This paper introduces the basic conception of information fusion and some fusion diagnosis methods commonly used nowadays in rotating machinery. From the thought of the information fusion, a new quantitative feature index monitoring and diagnosing the vibration fault of rotating machinery, which is called distance of information entropy, is put forward on the basis of the singular spectrum entropy in time domain, power spectrum entropy in frequency domain, wavelet energy spectrum entropy, and wavelet space feature entropy in time-frequency domain. The mathematic deduction suggests that the conception of distance of information entropy is accordant with the maximum subordination principle in the fuzzy theory. Through calculation it has been proved that this method can effectively distinguish different fault types. Then, the accuracy of rotor fault diagnosis can be improved through the curve chart of the distance of information entropy at multi-speed.

关键词: rotating machinery     information fusion     fault diagnosis     Information entropy     distance of the information entropy    

Factors affecting production of nonaqueous peracetic acid in tubular packed reactors

ZHANG Tengyun, FAN Hongbo, ZHONG Li, CHUANG Karl

《化学科学与工程前沿(英文)》 2008年 第2卷 第2期   页码 196-203 doi: 10.1007/s11705-008-0037-9

摘要: The synthesis of nonaqueous peracetic acid in acetone by acetaldehyde oxidation was carried out in a tubular packed reactor. The influencing factors of the reacting system including packing material, oxygen carrier, and reactor configuration were investigated. The results show that porous materials are inappropriate for peracetic acid synthesis and only non porous material with appropriate surface area can provide good peracetic acid selectivity and yield. Among the six kinds of packing material investigated, SA-5118 is the best one. As oxidizing gas, pure oxygen is superior to air. The optimum length-to-inner diameter ratio of the reactor is about 40. Under the proper reaction conditions, the highest peracetic acid yield of 84.15% and the highest selectivity of 93.34% can be achieved which indicates that the novel reacting system is effective and economical for nonaqueous peracetic acid production.

Imbalanced fault diagnosis of rotating machinery using autoencoder-based SuperGraph feature learning

《机械工程前沿(英文)》 2021年 第16卷 第4期   页码 829-839 doi: 10.1007/s11465-021-0652-4

摘要: Existing fault diagnosis methods usually assume that there are balanced training data for every machine health state. However, the collection of fault signals is very difficult and expensive, resulting in the problem of imbalanced training dataset. It will degrade the performance of fault diagnosis methods significantly. To address this problem, an imbalanced fault diagnosis of rotating machinery using autoencoder-based SuperGraph feature learning is proposed in this paper. Unsupervised autoencoder is firstly used to compress every monitoring signal into a low-dimensional vector as the node attribute in the SuperGraph. And the edge connections in the graph depend on the relationship between signals. On the basis, graph convolution is performed on the constructed SuperGraph to achieve imbalanced training dataset fault diagnosis for rotating machinery. Comprehensive experiments are conducted on a benchmarking publicized dataset and a practical experimental platform, and the results show that the proposed method can effectively achieve rotating machinery fault diagnosis towards imbalanced training dataset through graph feature learning.

关键词: imbalanced fault diagnosis     graph feature learning     rotating machinery     autoencoder    

―Summary of investigations on rotating cavity at IDG, RWTH Aachen University

Dieter BOHN, Jing REN,

《能源前沿(英文)》 2009年 第3卷 第4期   页码 489-497 doi: 10.1007/s11708-009-0040-y

摘要: Annular cavities are found inside rotor shafts of turbomachines with an axial or radial throughflow of cooling air, which influences the thermal efficiency and system reliability of the gas turbines. The flow and heat transfer phenomena in those cavities should be investigated in order to minimize the thermal load and guarantee the system reliability. An experimental rig is set up in the Institute of Steam and Gas Turbines, RWTH Aachen University, to analyze the flow structure inside the rotating cavity with an axial throughflow of cooling air. The corresponding 3D numerical investigation is conducted with the in-house flow solver CHTflow, in which the Coriolis force and the buoyancy force are implemented in the time-dependent Navier-Stokes equations. Both the experimental and numerical results show that the whole flow structure rotating slower than the cavity rotating speed. The flow passing the observation windows in the experimental and numerical results indicates the quite similar trajectories. The computed sequences and periods of the vortex flow structure correspond closely with those observed in the experiment. Furthermore, the numerical analysis reveals a flow pattern changing between single pair, double pair, and triple pair vortices. It is suggested that the vortices inside the cavity are created by the gravitational buoyancy force in the investigated case, while the number and strength of the vortices are controlled mainly by the Coriolis force.

关键词: rotating cavity     buoyancy     unsteady flow    

Design and realization of a remote monitoring and diagnosis and prediction system for large rotating

Shaohong WANG, Tao CHEN, Jianghong SUN

《机械工程前沿(英文)》 2010年 第5卷 第2期   页码 165-170 doi: 10.1007/s11465-009-0090-1

摘要: Traditional on-site fault diagnosis means cannot meet the needs of large rotating machinery for its performance and complexity. Remote monitoring and diagnosis technology is a new fault diagnosis mode combining computer technology, communication technology, and fault diagnosis technology. The designed remote monitoring and diagnosis and prediction system for large rotating machinery integrates the distributed resources in different places and breaks through shortcomings as the offline and decentralized information. The system can make further implementation of equipment prediction technology research based on condition monitoring and fault diagnosis, provide on-site analysis results, and carry out online actual verification of the results. The system monitors real-time condition of the equipment and achieves early fault prediction with great significance to guarantee safe operation, saves maintenance costs, and improves utilization and management of the equipment.

关键词: large rotating machinery     remote monitoring     fault diagnosis     prediction system    

Convective mass transfer from a horizontal rotating cylinder in a slot air jet flow

Hongting MA , Dandan MA , Na YANG ,

《能源前沿(英文)》 2009年 第3卷 第3期   页码 289-296 doi: 10.1007/s11708-009-0019-8

摘要: The effects of air jet impinging on the mass transfer characteristics from a rotating spinning cylinder surface were experimentally investigated. The effects of rotational Reynolds number

关键词: air jet impinging     rotating cylinder     critical point     mass transfer characteristics    

标题 作者 时间 类型 操作

simulated flue gas using aqueous persulfate with activation of ferrous ethylenediaminetetraacetate in the rotatingpacked bed

期刊论文

High-gravity intensified iron-carbon micro-electrolysis for degradation of dinitrotoluene

期刊论文

Preparation of transparent BaSO

Le Fang, Qian Sun, Yong-Hong Duan, Jing Zhai, Dan Wang, Jie-Xin Wang

期刊论文

Thermal performance of a single-layer packed metal pebble-bed exposed to high energy fluxes

Shengchun ZHANG, Zhifeng WANG, Hui BIAN, Pingrui HUANG

期刊论文

Abatement of mixed volatile organic compounds in a catalytic hybrid surface/packed-bed discharge plasma

Lianjie Guo, Nan Jiang, Jie Li, Kefeng Shang, Na Lu, Yan Wu

期刊论文

Large-scale industrial manufacturing of carbon nanotubes in a continuous inclined mobile-bed rotating

Sophie L. Pirard, Sigrid Douven, Jean-Paul Pirard

期刊论文

堆积床相变储热系统中径向孔隙率振荡分布对热性能的影响

刘红兵, 赵长颖

期刊论文

Simultaneous CO

Jie ZHU,Wei WANG,Xiuning HUA,Zhou XIA,Zhou DENG

期刊论文

Nonlinear dynamic behavior of rotating blade with breathing crack

Laihao YANG, Zhu MAO, Shuming WU, Xuefeng CHEN, Ruqiang YAN

期刊论文

New method of fault diagnosis of rotating machinery based on distance of information entropy

Houjun SU, Tielin SHI, Fei CHEN, Shuhong HUANG

期刊论文

Factors affecting production of nonaqueous peracetic acid in tubular packed reactors

ZHANG Tengyun, FAN Hongbo, ZHONG Li, CHUANG Karl

期刊论文

Imbalanced fault diagnosis of rotating machinery using autoencoder-based SuperGraph feature learning

期刊论文

―Summary of investigations on rotating cavity at IDG, RWTH Aachen University

Dieter BOHN, Jing REN,

期刊论文

Design and realization of a remote monitoring and diagnosis and prediction system for large rotating

Shaohong WANG, Tao CHEN, Jianghong SUN

期刊论文

Convective mass transfer from a horizontal rotating cylinder in a slot air jet flow

Hongting MA , Dandan MA , Na YANG ,

期刊论文