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Investigation of the segregation of a binary particle mixture in a square circulating fluidized bed with air staging

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Particuology 2019年第6期17卷 70-76页

作者： Mingkun Du Shuai Wang Guangdong institute of special equipment inspection and research Zhuhai Inspection InstituteZhuhai 519002China School of Energy Science and Engineering Harbin Institute of TechnologyHarbin 150001China

To further understand the segregation characteristics of a binary particle mixture in a riser,the flow behaviors of particles with different sizes were experimentally and numerically investigated in a cold square circulating fluidized *** impact of the gas velocity,solid circulation rate,initial coarse particle fraction,and air staging on the coarse particle fraction and axial pressure drop were *** experimental results show that air staging can significantly promote the pressure drop of a binary mixture at the bottom of the bed compared with that of monosized ***,the segregation of the binary mixture at the bottom is *** was also found that there was clear radial segregation owing to a higher coarse particle fraction near the wall compared with the bed's center and its corner.

关键词： Circulating fluidized bed Binary mixture Segregation Air staging

Improving the Thermal Conductivity and Mechanical Properties of Twocomponent Room Temperature Vulcanized Silicone Rubber by Filling with Hydrophobically Modified SiO_2-Graphene Nanohybrids

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Chinese Journal of Polymer Science 2019年第2期37卷 189-196页

作者： Bo Yang Shuang-Hong Zhang Yi-Feng Zou Wen-Shi Ma Guo-Jia Huang Mao-Dong Li Guangzhou special Pressure equipment inspection and research institute School of Materials Science and Technology South China University of Technology

The SiO_2 nanoparticles were coated on the surface of graphene oxide(GO) by sol-gel method to get the SiO_2-G *** SiO_2-G was restored and oleophylically modified to prepare hydrophobic modified SiO_2-G(HM-SiO_2-G) which was subsequently added to silicone rubber matrix to prepare two-component room temperature vulcanized(RTV-2) thermal conductive silicone rubber. The morphology, chemical structure and dispersity of the modified graphene were characterized with SEM, FTIR, Raman, and XPS *** addition, the heat-resistance behavior, mechanical properties, thermal conductivity, and electrical conductivity of the RTV-2 silicone rubber were also studied systematically. The results showed that the SiO_2 nanoparticles were coated on graphene oxide successfully, and HM-SiO_2-G was uniformly dispersed in RTV-2 silicone rubber. The addition of HM-SiO_2-G could effectively improve the thermal stability, mechanical properties and thermal conductivity of RTV-2 silicone rubber and had no great influence on the electrical insulation performance.

关键词： Graphene Modification Two components Room temperature vulcanized silicone rubber Thermal conductivity

Influence of laser re-melting and vacuum heat treatment on plasma-sprayed FeCoCrNiAl alloy coatings

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Journal of Iron and Steel research International 2017年第12期24卷 1199-1205页

作者： Dan-yang Lin Nan-nan Zhang Bin He Bing-qian Jin Yue Zhang De-yuan Li Fu-yu Dong Department of Material Science and Engineering Shenyang University of Technology Department of Pipeline Shenyang Institute of Special Equipment Inspection & Research

FeCoCrNiAl high entropy alloy coatings were prepared by supersonic air-plasma *** coatings were post-treated by vacuum heat treatment at 600 and 900°C,and laser re-melting with 300 W,respectively,to study the influence of different treatments on the structure and properties of the *** phase constitution,microstructure and microhardness of the coatings after treatments were investigated using X-ray diffraction,scanning electron microscopy and energy dispersive *** showed that the as-sprayed coatings consisted of pure metal and *** AlNi;phase was obtained after the vacuum heat treatment process.A body-centered cubic structure with less AlNi;could be found in the coating after the laser re-melting *** average hardness values of the as-sprayed coating and the coatings with two different temperature vacuum heat treatments and with laser re-melting were 177,227,266 and 682 HV,*** suggests that the vacuum heat treatment promoted the alloying process of the coatings,and contributed to the enhancement of the coating wear *** laser re-melted coating showed the best wear resistance.

关键词： Plasma spray High entropy alloy Vacuum heat treatment Laser re-melting FeCoCrNiAl alloy coating

Mechanical Behavior of Plastic Pipe Reinforced by Cross-Winding Steel Wire Subject to Foundation Settlement

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Transactions of Nanjing University of Aeronautics and Astronautics 2015年第3期32卷 348-354页

作者：李翔施建峰李军何兴建 China special equipment inspection and research Institude institute of Pressure equipment Zhejiang University institute of Chemical Engineering China University of Petroleum(Beijing)

Plastic pipe reinforced by cross helically wound steel wires(PSP)is a new plastic-matrix steel composite pipe developed in *** investigate the stress of PSP under foundation settlement,a finite element model(FEM)is *** stresses and strains of PSP are obtained by the FEM *** mechanic behavior of PSP subject to a foundation settlement is ***,the influence factor analysis of settlement deformation,such as settlement depth,overlying soil depth,diameter of PSP and inner pressure of PSP,are discussed.

关键词： composite pipe finite element model(FEM) internal

Load Bearing Capacity and Safety Analysis for Strain-hardening Austenitic Stainless Steel Pressure Vessels

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Chinese Journal of Mechanical Engineering 2011年第2期24卷 179-186页

作者： CHEN Gang DENG Yangchun China special equipment Safety Supervision Administration General Administration of Quality Supervision and Inspection and Quarantine of the People＇s Republic of China Beijing 100088 China Hubei Provincial special equipment Safety inspection and research institute Wuhan 430077 China

By increasing the yield strengths of austenitic stainless steels for pressure vessels with strain hardening techniques,the elastic load bearing capacity of austenitic stainless steel pressure vessels can be significantly *** kinds of strain hardening methods are often used for austenitic stainless steel pressure vessels：Avesta model for ambient temperature applications and Ardeform model for cryogenic temperature *** methods are obtained from conventional design rules based on the linear elastic theory,and only consider the hardening effect from *** this limits the applications of strain hardening techniques for austenitic stainless steel pressure vessels because of safety *** paper investigates the effect of strain hardening on the load bearing capacity of austenitic stainless steel pressure vessels under large deformation,based on the elastic-plastic ***,to understand the effect of strain hardening on material behavior,the plastic instability loads of a round tensile bar specimen are derived under two different loading paths and validated by ***,to investigate the effect of strain hardening on pressure vessels strength, the plastic instability pressure under strain hardening is derived and further validated by finite element ***,the safety margin of pressure vessels after strain hardening is analyzed by comparing the safety factor values calculated from bursting tests,finite element analyses,and *** researching results show that the load bearing capacity of pressure vessels at ambient temperature is independent of the loading history when the effects of both material strain hardening and structural deformation are *** element simulations and bursting tests results show that the minimum safety factor of austenitic stainless steel pressure vessels with 5% strain hardening is close to the recommended value for common pressure vessels specified in th

关键词： pressure vessel austenitic stainless steel strain hardening load bearing capacity safety margin

BIOLOGICAL INVASION PROBLEM WITH FREE BOUNDARY NONLOCAL DIFFUSION EQUATION

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数学杂志 2025年第1期45卷 48-56页

作者： HE Yu-rong ZHANG Ya-rong School of Science Xi'an University of Architecture and TechnologyXi'an 710055China Xi'an special equipment inspection institute Xi'an 710065China School of Power and Energy Northwestern Polytechnical UniversityXi'an 710072China

In order to better describe the phenomenon of biological invasion,this paper introduces a free boundary model of biological ***,the right free boundary is added to the equation with logistic ***,the existence and uniqueness of local solutions are proved by the Sobolev embedding theorem and the comparison ***,according to the relevant research data and contents of red fire ants,the diffusion area and nest number of red fire ants were simulated without external *** paper mainly simulates the early diffusion process of red fire *** the early diffusion stage,red fire ants grow slowly and then spread over a large area after reaching a certain number.

关键词： Free boundary biological invasion differential equation

Acoustic emission detection of 316L stainless steel welded joints during intergranular corrosion

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International Journal of Minerals,Metallurgy and Materials 2015年第9期22卷 942-949页

作者： Meng-yu Chai Quan Duan Wen-jie Bai Zao-xiao Zhang Xu-meng Xie School of Chemical Engineering and Technology Xi'an Jiaotong University Zhejiang Provincial special equipment inspection institute

This study analyzes acoustic emission （AE） signals during the intergranular corrosion （IGC） process of 316L stainless steel welded joints under different welding currents in boiling nitric acid. IGC generates several AE signals with high AE activity. The AE technique could hardly distinguish IGC in stainless steel welded joints with different welding heat inputs. However, AE signals can effectively distinguish IGC characteristics in different corrosion stages. The IGC resistance of a heat-affected zone is lower than that of a weld zone. The initiation and rapid corrosion stages can be distinguished using AE results and microstructural analysis. Moreover, energy count rate and amplitude are considered to be ideal parameters for characterizing different IGC processes. Two types of signals are detected in the rapid corrosion stage. It can be concluded that grain boundary corrosion and grain separation are the AE sources of type 1 and type 2, respectively.

关键词： stainless steel intergranular corrosion acoustic emission microstructure weight loss

Experimental investigation of flame propagation characteristics in the in-line crimped-ribbon flame arrester

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Science China(Technological Sciences) 2017年第5期60卷 678-691页

作者： SUN ShaoChen DING ChunHui HU XiYu LIU Gang YE Chen BI MingShu School of Chemical Machinery Dalian University of Technology Dalian 116024 China Shenyang institute of special equipment inspection and research Shenyang 110179 China

An experimental system that consisted of gas mixing equipment, a sensor detection system, a data acquisition device, and an electric spark ignition device was set up to investigate fuel/air deflagration flame propagation and quenching processes through a crimped-ribbon flame arrester in an enclosed horizontal pipe. Deflagration suppression experiments showed that when the concentration of flammable gas was close to the stoichiometric ratio, the evolution processes of explosion pressure for the propane-air and ethylene-air premixed gases in the pipe diameter （DN32-DN400） were similar and could be divided into four stages： isobaric combustion, slow pressure rise, quick pressure rise, and pressure oscillation. However, the explosion duration of the hydrogen-air premixed gas was relatively short, and the peak explosion pressure was high. The pressure rose quickly after the isobaric combustion stage. Therefore, the process can be divided into three stages in the pipe diameter （DN15-DN150）. Deflagration speed results indicated that the propane-air flame speed initially increased and eventually decreased along with increases in the pipe diameter （DN32-DN400）; however, the ethylene-air flame speed gradually increased with the increase of the pipe diameter （DNS0-DN400）. No notable pattern of change in the hydrogen-air flame speed was observed in the pipe diameter （DN15-DN150）. The maximum propane-air flame speed occurred at 5% concentration. The maximum flame speed for ethylene-air and hydrogen-air happened when the mixture was close to stoichiometric ratio. Under the conditions of the same size of experimental tube configuration and the same ignition distance but different pipe lengths, or the same pipe length but different ignition distances, experimental results showed that the flame arrester successfully stopped the flames at high flame speed and low explosion pressure, but failed at low flame speed and high explosion pressure.

关键词： deflagration flame crimped-ribbon flame arrester explosion pressure flame speed flammable gas concentration

Variational Wavelet Ensemble Empirical(VWEE)Denoising Method for Electromagnetic Ultrasonic Signal in High‑Temperature Environment with Low‑Voltage Excitation

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Chinese Journal of Mechanical Engineering 2022年第6期35卷 312-325页

作者： Jinjie Zhou Shuaijie Zhao Yang Zheng Xingquan Shen Jitang Zhang School of Mechanical Engineering North University of ChinaTaiyuan 030051China China special equipment inspection and research institute Beijing 100029China

Low excitation voltage for an electromagnetic acoustic transducer(EMAT)is necessary for the petrochemical equipment and facilities inspection,which work at high-temperatures,to avoid potential ***,low excitation voltage causes low signal-to-noise ratio(SNR)signals that are difficult to extract features,especially in a high-temperature environment,which causes high *** this study,a denoising method called the variational wavelet ensemble empirical(VWEE)method was proposed by combining the advantages of the variational modal decomposition(VMD),wavelet threshold(WT)denoising,and ensemble empirical mode decomposition(EEMD)*** validate the VWEE method,EMAT signals obtained in the temperature range of 25 to 700°C were *** results show that,compared with VMD,WT and empirical mode decomposition denoising methods,the SNR of proposed method is improved more than two *** VWEE method dramatically improved the SNR of a high-temperature EMAT signal and enhanced the accuracy of defect echos extraction.

关键词： EMAT High temperature Low excitation voltage SNR