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Numerical and Experimental Study on Flow-induced Noise at Blade-passing Frequency in Centrifugal Pumps

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Chinese Journal of Mechanical engineering 2014年第3期27卷 606-614页

作者： YANG Jun YUAN Shouqi YUAN Jianping SI Qiaorui PEI Ji research center of Fluid Machinery engineering and Technology Jiangsu University

With the increasing noise pollution, low noise optimization of centrifugal pimps has become a hot topic. However, experimental study on this problem is unacceptable for industrial applications due to unsustainable cost. A hybrid method that couples computational fluid dynamics （CFD） with computational aeroacoustic software is used to predict the flow-induced noise of pumps in order to minimize the noise of centrifugal pumps in actual projects. Under Langthjem＇s assumption that the blade surface pressure is the main flow-induced acoustic source in centrifugal pumps, the blade surface pressure pulsation is considered in terms of the acoustical sources and simulated using CFX software. The pressure pulsation and noise distribution in the near-cutoff region are examined for the blade-passing frequency （BPF） noise, and the sound pressure level （SPL） reached peaks near the cutoff that corresponded with the pressure pulsation in this region. An experiment is performed to validate this prediction. Four hydrophones are fixed to the inlet and outlet ports of the test pump to measure the flow-induced noise from the four-port model. The simulation results for the noise are analyzed and compared with the experimental results. The variation in the calculated noise with changes in the flow agreed well with the experimental results. When the flow rate was increased, the SPL first decreased and reached the minimum near the best efficient point （BEP）; it then increased when the flow rate was further increased. The numerical and experimental results confirmed that the BPF noise generated by a blade-rotating dipole roughly reflects the acoustic features of centrifugal pumps. The noise simulation method in current study has a good feasibility and suitability, which could be adopted in engineering design to predict and optimize the hydroacoustic behavior of centrifugal pumps.

关键词： centrifugal pumps flow-induced noise prediction blade-passing noise blade surface pressure pulsations

Co-pyrolysis of bituminous coal and biomass in a pressured fluidized bed

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Chinese Journal of Chemical engineering 2019年第7期27卷 1666-1673页

作者： Yong Huang Ningbo Wang Qiaoxia Liu Wusheng Wang Xiaoxun Ma School of Chemical engineering Northwest University229 North Taibai RoadXi’an 710069China Hydrocarbon High-efficiency Utilization Technology research center of Yanchang Petroleum (Group) Co.Ltd. Xi’an 710075China Chemical engineering research center of the Ministry of Education (MOE) for Advanced Use Technology of Shanbei Energy Xi’an 710069China shaanxi research center of engineering Technology for Clean Coal Conversion Xi’an 710069China Collaborative Innovation center for Development of Energy and Chemical Industry in Northern shaanxi Xi’an 710069China International Scientific and Technological Cooperation Base of the Ministry of Science and Technology (MOST) for Clean Utilization of Hydrocarbon Resources Xi’an 710069China

An experimental study on co-pyrolysis of bituminous coal and biomass was performed in a pressured fluidized bed *** blend ratio of biomass in the mixture was varied between 0 and 100 wt%,and the temperature was over a range of 550–650℃ under 1.0 MPa pressure with different *** the basis of the individual pyrolysis behavior of bituminous coal and biomass,the influences of the biomass blending ratio,temperature,pressure and atmosphere on the product distribution were *** results indicated that there existed a synergetic effect in the co-pyrolysis of bituminous coal and biomass in this pressured fluidized bed reactor,especially when the condition of bituminous coal and biomass blend ratio of 70:30(w/w),600℃,and 0.3 MPa was *** addition of biomass influenced the tar and char yields and gas and tar composition during *** tar yields were higher than the calculated values from individual pyrolysis of each fuel,and consequently the char yields were *** experimental results showed that the composition of the gaseous products was not in accordance with those of their individual *** improvement of composition in tar also indicated synergistic effect in the co-pyrolysis.

关键词： Bituminous coal Biomass Co-pyrolysis Pressured fluidized bed Synergistic effect

The influence of the flow rate on periodic flow unsteadiness behaviors in a sewage centrifugal pump

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Journal of Hydrodynamics 2013年第5期25卷 702-709页

作者：裴吉袁寿其袁建平王文杰 research center of Fluid Machinery engineering and Technology Jiangsu University

To design a single-blade pump with a good performance in a wide operational range and to increase the pump reliability in the multi-conditional hydraulic design process, an understanding of the unsteady flow behaviors as related with the flow rate is very important. However, the traditional design often considers only a single design condition, and the unsteady flow behaviors have not been well studied for single-blade pumps under different conditions. A comparison analysis of the flow unsteadiness behaviors at di- fferent flow rates within the whole flow passage of the pump is carried out in this paper by solving the three-dimensional unsteady Reynolds-averaged Navier-Stokes equations with the Shear Stress Transport （SST） turbulence model. A definition of the unsteadiness in the pump is made and applied to analyze the unsteady intensity distributions, and the flow rate effect on the complex unsteady flow in the pump is studied quantitatively while the flow mechanism is also analyzed. The CFD results are validated by experimental data collected at the laboratory. It is shown that a significant flow rate effect on the time-averaged unsteadiness and the turbulence intensity distribution can be observed in both rotor and stator domains including the side chamber. The findings would be useful to reduce the flow unsteadiness and to increase the pump reliability under multi-conditions.

关键词： flow rate effect flow unsteadiness turbulence intensity sewage centrifugal pump multi-conditions

TBM滚刀刀圈再制造热处理工艺仿真优化与试验研究

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表面工程与再制造 2024年第1期24卷 63-63页

作者： Kui Zhang Shuhao Dai Boyan Jiang Dinghua Wang Cheng Han Qingyu Liu Postdoctoral research Station for Mechanics Xiangtan University Xiangtan 411105 China engineering research center of Complex Tracks Processing Technology and Equipment of Ministry of Education Xiangtan University Xiangtan 411105 China School of Mechanical engineering and Mechanics Xiangtan University Xiangtan 411105 China China Railway Sunward engineering Equipment Co. Ltd. Guangzhou 511400 China

在“双碳”目标的背景下,本研究旨在降低隧道掘进机失效滚刀刀圈(以下简称刀圈)更换带来的金属资源消耗。为此,首次提出了一种考虑金属活性气体保护焊预热和焊后回火关键热处理工艺的刀圈再制造方法。首先,建立有限元模型对该再制造工... 详细信息

在“双碳”目标的背景下,本研究旨在降低隧道掘进机失效滚刀刀圈(以下简称刀圈)更换带来的金属资源消耗。为此,首次提出了一种考虑金属活性气体保护焊预热和焊后回火关键热处理工艺的刀圈再制造方法。首先,建立有限元模型对该再制造工艺路线进行模拟,确立了预热和回火温度的最佳参数范围。

关键词：热处理工艺回火温度再制造工艺隧道掘进机仿真优化最佳参数滚刀刀圈活性气体保护焊

Metallaphotoredox-Catalyzed Three-Component Couplings for Practical Synthesis of Ureas and Carbamates

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Chinese Journal of Chemistry 2024年第3期42卷 264-270页

作者： Ernest Koranteng Zhen-Cao Shu Yi-Yin Liu Qian Yang Bin Shi Qiang-Xian Wu Fen Tan Liang-Qiu Lu Wen-Jing Xiao engineering research center of Photoenergy Utilization for Pollution Control and Carbon Reduction Ministry of EducationCollege of ChemistryCentral China Normal University152 Luoyu RoadWuhanHubei430079 China Wuhan Youji Industries Co. LtdNo.1 2nd Chemical Rd.WuhanHubei430082 China Hubei Key Laboratory of Purification and Application of Plant Anti-cancer Active Ingredients School of Chemistry and Life SciencesHubei University of EducationWuhanHubei430205 China State Key Laboratory for Oxo Synthesis and Selective Oxidation Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhouGansu730000 China School of Chemistry and Chemical engineering Henan Normal UniversityXinxiangHenan453007 China Wuhan Institute of Photochemistry and Technology WuhanHubei430082 China State Key Laboratory of Organometallic Chemistry Shanghai Institute of Organic ChemistryChinese Academy of SciencesShanghai200032 China

Ureas are widely used in drugs,materials and catalysts because of their diamide structure,which can form strong hydrogen ***,it is of great scientific significance to develop efficient and green methods for the synthesis of urea compounds,especially unsymmetrical ***,we have disclosed novel and highly efficient three-component coupling reactions of organic halides,sodium cyanate and amines enabled by nickel/photoredox dual catalysis for the preparation of unsymmetrical *** reaction features simple and safe operations,broad substrate scopes,and product *** allows the facile synthesis of N-aryl/vinyl ureas from readily available,user-friendly feedstocks under mild conditions(27 examples,36%—98%yields).In addition,this method is further derived to alcohols as nucleophiles to synthesize a series of carbamates(15 examples,40%—95%yields).The mechanism experiment shows that the isocyanate produced by the coupling of halide and sodium cyanate may be the key intermediate in this reaction.

关键词： Cross-coupling Nickel Photoredox catalysis Three-component reaction Ureas Carbamates

Preparation and characterization of Fe_(3)O_(4)/Au composite particles

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Science China Chemistry 2004年第2期47卷 152-158页

作者： CUI Yali HUI Wenli WANG Huirong WANG Lijun CHEN Chao Biochip research and Development center Northwest University National Engineering Research Center for Miniaturized Detection System Xi'an 710069 China Biochip Research and Development Center Northwest University National Engineering Research Center for Miniaturized Detection System Xi'an 710069 China Biochip Research and Development Center Northwest University National Engineering Research Center for Miniaturized Detection System Xi'an 710069 China Biochip Research and Development Center Northwest University National Engineering Research Center for Miniaturized Detection System Xi'an 710069 China Biochip Research and Development Center Northwest University National Engineering Research Center for Miniaturized Detection System Xi'an 710069 China

Using Fe3O4 nano-particles as seeds, a new type of Fe3O4/Au composite particles with core/shell structure and diameter of about 170 nm was prepared by reduction of Au3+ with hydroxylamine in an aqueous solution. Particle size analyzer and transmission electron micro-scope were used to analyze the size distribution and microstructure of the particles in different conditions. The result showed that the magnetically responsive property and suspension stability of Fe3O4 seeds as well as reduction conditions of Au3+ to Au0 are the main factors which are crucial for obtaining a colloid of the Fe3O4/Au composite particles with uniform particle dispersion, excellent stability, homogeneity in particle sizes, and effective response to an external magnet in aqueous suspension solutions. UV-Vis analysis revealed that there is a characteristic peak of Fe3O4/Au fluid. For particles with d(0.5)=168 nm, the lmax is 625 nm.

关键词： Fe3O4/Au, core/shell structure, composite particle, preparation, properties.

Distributed fixed-time observers for linear time-invariant systems

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Kongzhi yu Juece/Control and Decision 2024年第11期39卷 3664-3672页

作者： Zhang T. Wu H.-Y. Zhu Z.-H. Zheng X.-J. Guan Z.-H. engineering research center for Metallurgical Automation and Measurement Technology of Ministry of Education Wuhan University of Science and Technology Wuhan 430081 China Institute of Robotics and Intelligent Systems Wuhan University of Science and Technology Wuhan 430081 China School of Artificial Intelligence and Automation Huazhong University of Science and Technology Wuhan 430074 China

A class of distributed fixed-time convergent observers is designed based on the bi-limit weighted homogeneous approximation theory and observability decomposition for the distributed state estimation of linear time-invariant systems. Firstly, for a single-input-single-output integrating chain system, a centralized fixed-time observer is designed for the system using bi-limit weighted homogeneous estimation. Then, the linear time-invariant system is decomposed into observable and unobservable subsystems based on the observability decomposition. Each agent in the sensor network reconstructs local observable sub-states in a fixed time based on the centralized observer by using only the system output measurements, and then state information between the agents is used to construct a consistent algorithm to estimate the local unobservable sub-states in a fixed time, thus realizing state omniscience in a fixed time. Unlike previous works, this paper does not need to construct a specific Lyapunov function to give an expression for the convergence time. Finally, the effectiveness of the designed observer is verified by simulations. © 2024 Northeast University. All rights reserved.

关键词： distributed estimation fixed-time observer linear systems observability decomposition sensor networks weighted homogeneity

A direct atomic layer deposition method for growth of ultra-thin lubricant tungsten disulfide films

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Science China(Technological Sciences) 2017年第1期60卷 51-57页

作者： SUN YongFeng CHAI ZhiMin LU XinChun HE DanNong National engineering research center for Nanoteehnology Shanghai 200241 China

We describe a direct atomic layer deposition method to grow lubricant tungsten disulfide （WS2） films. The WS2 films were deposited on a Si （100） substrate and a zinc sulfide （ZnS） film coated the Si （100） substrate using tungsten hexacarbonyl and hydrogen sulfide as precursors. The ZnS film served as an intermediate layer to facilitate the nucleation and growth of the WS2 films. The thickness of the WS2 films was measured via scanning electron microscope, the microstructure was probed with an X-ray diffractometer and a transmission electron microscope. The friction coefficient was measured with a ball-on-disk tester under dry nitrogen. The results reveal that the WS2 films deposited on both substrates are N175 nm and have （002） and （101） crystal orientations. The WS2 film deposited on the ZnS coated Si substrate exhibits a stronger （002） orientation and a denser crystal structure than that deposited on the Si substrate. The WS2 films on both substrates have low friction coefficients. How- ever, due to the stronger （002） orientation and denser crystal structure, the friction coefficient of the WS2 film deposited on ZnS coated Si substrate is smaller with longer wear life.

关键词： atomic layer deposition tungsten disulfide crystal orientation friction

Bioactive titanium metal surfaces with antimicrobial properties prepared by anodic oxidation treatment

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Science China(Technological Sciences) 2009年第8期52卷 2269-2274页

作者： YUE ChongXia YANG BangCheng ZHANG XingDong engineering research center for Biomaterials Sichuan UniversityChengdu 610064China National engineering research center in Biomaterials Chengdu 610064China

In order to endow titanium metals with bioactivity and antimicrobial properties, titanium plates were subjected to anodic oxidation treatment in NaCl solutions in this study. The treated titanium metals could induce apatite formation in the fast calcification solution, and osteoblasts on the treated titanium surfaces proliferated well as those on the untreated titanium metal surfaces. The treated metals could inhibit S. aureus growth in the microbial culture experiments. It was assumed that Ti-OH groups and Ti-Cl groups formed on the treated titanium surface were responsible for the bioactivity and antimicrobial properties of the metals. The anodic oxidation treatment was an effective way to prepare bioactive titanium surfaces with antimicrobial properties.

关键词： titanium anodic oxidation bioactivity antimicrobial property