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基于Y-shaped路网的早高峰拼车定价策略
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作者 贺冬冬 仲秋雁 曲毅 《系统工程学报》 CSCD 北大核心 2023年第5期706-722,共17页
针对交通资源配置有限导致的早高峰通勤拥堵问题,借鉴共享经济理论,引入拼车出行概念,充分考虑通勤者出行方式和Y-shaped路网特点,建立了基于通勤者出行效益的拼车定价模型.模型结合费用补偿机制,讨论了以平台利润最大化和系统负效用最... 针对交通资源配置有限导致的早高峰通勤拥堵问题,借鉴共享经济理论,引入拼车出行概念,充分考虑通勤者出行方式和Y-shaped路网特点,建立了基于通勤者出行效益的拼车定价模型.模型结合费用补偿机制,讨论了以平台利润最大化和系统负效用最小化为目标的拼车定价策略,并给出了定价策略有效的阈值条件.研究结果表明,当通勤者都参与到拼车服务中时,拼车平台利润和交通系统负效用在其相应拼车定价策略下均能达到最优值,并且以交通系统负效用最小化为目标的拼车定价策略能消除Y-shaped路网中瓶颈处的交通拥堵. 展开更多
关键词 动态拼车 y-shaped瓶颈模型 拼车定价 早高峰通勤
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Flow equation and similarity criterion during centrifugal casting in micro-channel 被引量:2
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作者 任明星 王国田 +2 位作者 李邦盛 王振龙 傅恒志 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第5期1506-1511,共6页
Liquid metal filling flow process in the microscale during the centrifugal casting process was studied by means of similar physical simulation. The research was focused on derived similarity criterion. Based on the tr... Liquid metal filling flow process in the microscale during the centrifugal casting process was studied by means of similar physical simulation. The research was focused on derived similarity criterion. Based on the traditional flow equations, the flow equation and the Bernoulli's equation for liquid metal flows in micro-scale space were derived, which provides a mathematical model for numerical simulation of micro-scale flow. In the meanwhile, according to the micro-flow equation and the similarity theory, the similarity criterion for the physical simulation of the mold filling behaviors was presented under centrifugal force field, so as to achieve the visual observation and quantitative analysis of micro-flow process. 展开更多
关键词 micro-channel MICRO-FLOW centrifugal force field similarity criterion
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Solid-phase sintering process and forced convective heat transfer performance of porous-structured micro-channels 被引量:2
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作者 白鹏飞 易子川 +1 位作者 唐彪 周国富 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第3期900-906,共7页
A solid-phase sintering process for the low-cost fabrication of composite micro-channels was developed. Three kinds of composite micro-channels with metallic porous structures were designed. The sintering process was ... A solid-phase sintering process for the low-cost fabrication of composite micro-channels was developed. Three kinds of composite micro-channels with metallic porous structures were designed. The sintering process was studied and optimized to obtain porous-structured micro-channels with high porosity. The flow resistance and heat transfer performance in the composite micro-channels were investigated. The composite micro-channels show acceptable flow resistance, significant enhancement of heat transfer and dramatic improvement of flow boiling stability, which indicates a promising prospect for the application in forced convective heat transfer. 展开更多
关键词 solid-phase sintering composite micro-channels porous structure flow resistance convective heat transfer
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Similar physical simulation of microflow in micro-channel by centrifugal casting process
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作者 任明星 王国田 +2 位作者 李邦盛 王振龙 傅恒志 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第4期1094-1100,共7页
By means of similar physical simulation, liquid metal filling flow pattern in the microscale during the centrifugal casting process was studied. It was found that, in microscale, the flow channel with the maximum cros... By means of similar physical simulation, liquid metal filling flow pattern in the microscale during the centrifugal casting process was studied. It was found that, in microscale, the flow channel with the maximum cross-sectional area was filled first, and the micro flow channels with 0.1 mm in diameter were filled when the rotational speed was increased to 964 r/min. The total fluid energy remained constant during the mould filling, and the changes of cross-sectional area only occurred in the microflow channels with 0.3 mm in diameter. Filling velocity increased with processing time, and a peak value was achieved rapidly, followed by a gentle increase as the process proceeded further. The time required to achieve the peak filling rate decreased dramatically with increase of rotational speed. 展开更多
关键词 similar simulation MICROFLOW centrifugal casting micro-channel
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Guidelines and consensus:Jejunoileostomy for diabetes mellitussurgical norms and expert consensus(2023 version)
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作者 Ji-Wei Shen Chun-Yong Ji +10 位作者 Xue-Dong Fang Bo Yang Tian Zhang Zheng-Cai Li Hua-Zhi Li Zhi-Yi Liu Jun Tang Chuan-Wen Liao Ji-Zhou Lu Xuan Yang Xin-Guo Zhang 《World Journal of Diabetes》 SCIE 2024年第11期2182-2188,共7页
Diabetes mellitus(DM)is a group of diseases characterized by high blood glucose caused by insufficient absolute or relative secretion of insulin.Once diagnosed,patients need long-term treatment with hypoglycemic drugs... Diabetes mellitus(DM)is a group of diseases characterized by high blood glucose caused by insufficient absolute or relative secretion of insulin.Once diagnosed,patients need long-term treatment with hypoglycemic drugs.Currently,the existing first-line hypoglycemic drugs do not provide effective treatment for DM and its complications.In the past,the first generation and the second generation of weight loss surgery,such as gastric bypass and sleeve gastric surgery,had strict body mass index requirements.Moreover,post-surgery,patients are prone to fluctuating hypoglycemia,gastroesophageal reflux,and dumping syndrome.Hence,the curative effect of this type of surgery was compromised to a certain extent.Jejunoileostomy is a third-generation surgery for patients with DM,which has been shown to improve glucose and lipid metabolism,without changing the original gastrointestinal tract structure.Different from previous weight loss surgeries,jejunoileostomy has been clinically observed to delay the development of DM-related complications.Additionally,the postoperative complications are mild and do not affect the patient’s quality of life.Based on our clinical observations from multi-center large samples,our team developed a consensus on the operative period and perioperative management of jejunoileostomy as a reference for clinical researchers. 展开更多
关键词 SURGICAL Diabetes Weight loss surgery y-shaped anastomotic jejunal loops Jejunoileostomy
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Valley transport in Kekulé structures of graphene
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作者 王娟娟 汪军 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第1期44-53,共10页
Valleytronics is an emergent discipline in condensed matter physics and offers a new way to encode and manipulate information based on the valley degree of freedom in materials. Among the various materials being studi... Valleytronics is an emergent discipline in condensed matter physics and offers a new way to encode and manipulate information based on the valley degree of freedom in materials. Among the various materials being studied, Kekulé distorted graphene has emerged as a promising material for valleytronics applications. Graphene can be artificially distorted to form the Kekulé structures rendering the valley-related interaction. In this work, we review the recent progress of research on Kekulé structures of graphene and focus on the modified electronic bands due to different Kekulé distortions as well as their effects on the transport properties of electrons. We systematically discuss how the valley-related interaction in the Kekulé structures was used to control and affect the valley transport including the valley generation, manipulation, and detection. This article summarizes the current challenges and prospects for further research on Kekulé distorted graphene and its potential applications in valleytronics. 展开更多
关键词 GRAPHENE y-shaped Kekulé(Y-Kek)lattice distortion structure O-Kekulé(O-Kek)structure valley current
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Micromixing Efficiency of Viscous Media in Micro-channel Reactor 被引量:9
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作者 杨旷 初广文 +3 位作者 邵磊 向阳 张亮亮 陈建峰 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2009年第4期546-551,共6页
Micromixing efficiency of viscous media in Y-type micro-channel reactor was studied by using iodide-iodate test reaction as working system.Experiments were carried out in water-glycerin mixtures with 7 different visco... Micromixing efficiency of viscous media in Y-type micro-channel reactor was studied by using iodide-iodate test reaction as working system.Experiments were carried out in water-glycerin mixtures with 7 different viscosities.The experimental results showed that segregation index of the micro-channel reactor increases with the decrease of volumetric flow rate and the increase of solution viscosity.Based on the incorporation model,the micromixing time tm of the micro-channel reactor was estimated in the range of 10-4-10-3s at different viscosities,which indicated that the micro-channel reactor possesses a much better micromixing performance compared to the stirred tank(tm=0.02-0.2s). 展开更多
关键词 micro-channel reactor MICROMIXING incorporation model VISCOSITY
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Theory and Experimental Verification on Valveless Piezoelectric Pump with Multistage Y-shape Treelike Bifurcate Tubes 被引量:6
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作者 HUANG Jun ZHANG Jianhui +1 位作者 XUN Xianchao WANG Shouyin 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2013年第3期462-468,共7页
Among most traditional piezo water cooling systems, piezoelectric valve pumps are adopted as their driving sources. The valves in these pumps induce problems of shock and vibration and also make their structure compli... Among most traditional piezo water cooling systems, piezoelectric valve pumps are adopted as their driving sources. The valves in these pumps induce problems of shock and vibration and also make their structure complicated, which is uneasy to minimize and reduce their reliability and applicability of the whole system. In order to avoid these problems caused by valve structure, a novel valveless piezoelectric pump is developed, which integrates both functions of transforming and cooling. The pump’s Y-shape tree-like construction not only increases the efficiency of cooling but also the system reliability and applicability. Firstly, a multistage Y-shape treelike bifurcate tube is proposed, then a valveless piezoelectric pump with multistage Y-shape treelike bifurcate tubes is designed and its working principle is analyzed. Then, the theoretical analysis of flow resistance characteristics and the flow rate of the valveless piezoelectric pump are performed. Meanwhile, commercial software CFX is employed to perform the numerical simulation for the pump. Finally, this valveless piezoelectric pump is fabricated, the relationship between the flow rates and driving frequency, as well as the relationship between the back pressure and the driving frequency are experimentally investigated. The experimental results show that the maximum flow rate is 35.6 mL/min under 100 V peak-to-peak voltage (10.3 Hz) power supply, and the maximum back pressure is 55 mm H2O under 100 V (9 Hz) power supply, which validates the feasibility of the valveless piezoelectric pump with multistage Y-shape treelike bifurcate tubes. The proposed research provides certain references for the design of valveless piezoelectric pump and improves the reliability of piezo water cooling systems. 展开更多
关键词 PIEZOELECTRIC PUMP valveless y-shape tube treelike bifurcate
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Analysis of the Flow Rate Characteristics of Valveless Piezoelectric Pump with Fractal-like Y-shape Branching Tubes 被引量:7
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作者 HUANG Jun ZHANG Jianhui +1 位作者 WANG Shouyin LIU Weidong 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2014年第3期628-634,共7页
Microchannel heat sink with high heat transfer coefficients has been extensively investigated due to its wide application prospective in electronic cooling. However, this cooling system requires a separate pump to dri... Microchannel heat sink with high heat transfer coefficients has been extensively investigated due to its wide application prospective in electronic cooling. However, this cooling system requires a separate pump to drive the fluid transfer, which is uneasy to minimize and reduces their reliability and applicability of the whole system. In order to avoid these problems, valveless piezoelectric pump with fractal-like Y-shape branching tubes is proposed. Fractal-like Y-shape branching tube used in microchannel heat sinks is exploited as no-moving-part valve of the valveless piezoelectric pump. In order to obtain flow characteristics of the pump, the relationship between tube structure and flow rate of the pump is studied. Specifically, the flow resistances of fractal-like Y-shape branching tubes and flow rate of the pump are analyzed by using fractal theory. Then, finite element software is employed to simulate the flow field of the tube, and the relationships between pressure drop and flow rate along merging and dividing flows are obtained. Finally, valveless piezoelectric pumps with fractal-like Y-shape branching tubes with different fractal dimensions of diameter distribution are fabricated, and flow rate experiment is conducted. The experimental results show that the flow rate of the pump increases with the rise of fractal dimension of the tube diameter. When fractal dimension is 3, the maximum flow rate of the valveless pump is 29.16 mL/min under 100 V peak to peak (13 Hz) power supply, which reveals the relationship between flow rate and fractal dimensions of tube diameter distribution. This paper investigates the flow characteristics of valveless piezoelectric pump with fractal-like Y-shape branching tubes, which provides certain references for valveless piezoelectric pump with fractal-like Y-shape branching tubes in application on electronic chip cooling. 展开更多
关键词 PIEZOELECTRIC PUMP valveless fractal-like y-shape branching tube
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Gastrotracheal fistula:Treatment with a covered self-expanding Y-shaped metallic stent 被引量:2
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作者 Fei Wang Hong Yu +4 位作者 Ming-Hui Zhu Quan-Peng Li Xian-Xiu Ge Jun-Jie Nie Lin Miao 《World Journal of Gastroenterology》 SCIE CAS 2015年第3期1032-1035,共4页
A 67-year-old man had a sev-ere cough and pulmonary infection for 1 wk before seeking evaluation at our hospital.He had undergone esophagectomy with gastric pull-up and radiotherapy for esophageal cancer 3 years previ... A 67-year-old man had a sev-ere cough and pulmonary infection for 1 wk before seeking evaluation at our hospital.He had undergone esophagectomy with gastric pull-up and radiotherapy for esophageal cancer 3 years previously.After admission to our hospital,gastroscopy and bronchoscopy revealed a fistulous communication between the posterior tracheal wallnear the carina and the upper residual stomach.We measured the diameter of the trachea and bronchus and determined the site and size of the fistula using multislice computed tomography and gastroscopy.A covered self-expanding Y-shaped metallic stent was implanted into the trachea and bronchus.Subsequently,the fistula was closed completely.The patient tolerated the stent well and had good palliation of his symptoms. 展开更多
关键词 Gastrotracheal FISTULA y-shaped metallic STENT ESO
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Improved catalytic performance of Ni catalysts for steam methane reforming in a micro-channel reactor 被引量:4
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作者 Bozhao Chu Nian Zhang +2 位作者 Xuli Zhai Xin Chen Yi Cheng 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2014年第5期593-600,共8页
Milliseconds process to produce hydrogen by steam methane reforming (SMR) reaction, based on Ni catalyst rather than noble catalyst such as Pd, Rh or Ru, in micro-channel reactors has been paid more and more attenti... Milliseconds process to produce hydrogen by steam methane reforming (SMR) reaction, based on Ni catalyst rather than noble catalyst such as Pd, Rh or Ru, in micro-channel reactors has been paid more and more attentions in recent years. This work aimed to further improve the catalytic performance of nickel-based catalyst by the introduction of additives, i.e., MgO and FeO, prepared by impregnation method on the micro-channels made of metal-ceramic complex substrate. The prepared catalysts were tested in the same micro-channel reactor by switching the catalyst plates. The results showed that among the tested catalysts Ni-Mg catalyst had the highest activity, especially under harsh conditions, i.e., at high space velocity and/or low reaction temperature. Moreover, the catalyst activity and selectivity were stable during the 12 h on stream test even when the ratio of steam to carbon (SIC) was as low as 1.0. The addition of MgO promoted the active Ni species to have a good dispersion on the substrate, leading to a better catalytic performance for SMR reaction. 展开更多
关键词 hydrogen production steam methane reforming (SMR) nickel-based catalysts MgO promoter millisecond reaction micro-channel reactor
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NUMERICAL ANALYSIS OF GASEOUS FLOW IN MICRO-CHANNELS 被引量:1
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作者 XuJie GuChuangang WangTong 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2004年第4期575-578,共4页
The algorithm of gaseous flow in bi-dimensional micro-channels is set up andthe corresponding program based on micro-flow theory is presented. Gaseous flow in micro-channels isnumerically analyzed and the pressure dro... The algorithm of gaseous flow in bi-dimensional micro-channels is set up andthe corresponding program based on micro-flow theory is presented. Gaseous flow in micro-channels isnumerically analyzed and the pressure drop along the duct as well .as the velocity profile in themicro-channels is obtained. The numerical results agreed well with the experimental results in thereferences. Moreover, the effects of Kn, sigma_v and Re on the velocity profiles are analyzed. It isfound that for Kn>0.001, with increasing Kn number, the slip velocity on the wall boundaryincreases; the tangential momentum coefficient sigma_v affects the slip velocity greatly. The slipvelocity increases with decreasing a, In the slip flow regime and for low Re numbers, the slipvelocity is little influenced by the Re number. 展开更多
关键词 micro-channel Numerical analysis KN SLIP
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RESEARCH ON DIFFUSION IN MICRO-CHANNEL FLOW DRIVEN BY ELECTROOSMOSIS 被引量:1
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作者 张凯 林建忠 李志华 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2006年第5期575-582,共8页
Numerical simulation using the finite differential method was carried out to analyze the diffusion of an impulse sample in the micro-channel driven by electroosmosis. The results show that the electrical field strengt... Numerical simulation using the finite differential method was carried out to analyze the diffusion of an impulse sample in the micro-channel driven by electroosmosis. The results show that the electrical field strength applied externally and the concentration of buffer solution play a significant role in the diffusion of sample, however, hydraulic diameter and aspect ratio of height to width of channel play a small role in it. Weakening the electrical field strength applied externally and the concentration of buffer solution properly can prevent the sample band from broadening effectively, and promote the efficiency of testing and separation as well as keep a faster speed of transport. The conclusions are helpful to the optimal design for micro-channel. 展开更多
关键词 micro-channel DIFFUSION driven by electroosmosis numerical simulation
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Y-shaped block copolymers of poly(ethylene glycol) and poly(N-isopropylacrylamide) synthesized by ATRP 被引量:2
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作者 Xin De Tang Xiao Chao Liang Nian Feng Han 《Chinese Chemical Letters》 SCIE CAS CSCD 2009年第11期1353-1356,共4页
Novel Y-shaped block copolymers of poly(ethylene glycol) and poly(N-isopropylacrylamide), PEG-b-(PNIPAM)2, were successfully synthesized through atom transfer radical polymerization (ATRP). A difunctional macr... Novel Y-shaped block copolymers of poly(ethylene glycol) and poly(N-isopropylacrylamide), PEG-b-(PNIPAM)2, were successfully synthesized through atom transfer radical polymerization (ATRP). A difunctional macroinitiator was prepared by esterification of 2,2-dichloroacetyl chloride with poly(ethylene glycol) monomethyl ether (PEG). The copolymers were obtained via the ATRP ofN-isopropylacrylamide (NIPAM) at 30℃ with CuCl/Me6TREN as a catalyst system and DMF/H2O (v/v = 3:1) mixture as solvent. The resulting copolymers were characterized by gel permeation chromatography (GPC) and ^1H NMR. These block copolymers show controllable molecular weights and narrow molecular weight distributions (PDI 〈 1.15). Their phase transition temperatures and the corresponding enthalpy changes in aqueous solution were measured by differential scanning calorimetry (DSC). As a result, the phase transition temperature of PEG45-b-(PNIPAM55)2 is higher than that of PNIPAM, however, the corresponding enthalpy change is much lower, indicating the significant influence of the macromolecular composition and architecture on the phase transition. 展开更多
关键词 y-shaped Block copolymer Poly(ethylene glycol) Poly(N-isopropylacrylamide) Atom transfer radical polymerization (ATRP)
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Flow characteristics of supersonic gas passing through a circular micro-channel under different inflow conditions
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作者 Guang-Ming Guo Qin Luo +1 位作者 Lin Zhu Yi-Xiang Bian 《Chinese Physics B》 SCIE EI CAS CSCD 2019年第6期270-283,共14页
Gas flow in a micro-channel usually has a high Knudsen number. The predominant predictive tool for such a microflow is the direct simulation Monte Carlo(DSMC) method, which is used in this paper to investigate primary... Gas flow in a micro-channel usually has a high Knudsen number. The predominant predictive tool for such a microflow is the direct simulation Monte Carlo(DSMC) method, which is used in this paper to investigate primary flow properties of supersonic gas in a circular micro-channel for different inflow conditions, such as free stream at different altitudes, with different incoming Mach numbers, and with different angles of attack. Simulation results indicate that the altitude and free stream incoming Mach number have a significant effect on the whole micro-channel flow field, whereas the angle of attack mainly affects the entrance part of micro-channel flow field. The fundamental mechanism behind the simulation results is also presented. With the increase of altitude, thr free stream would be partly prevented from entering into micro-channel.Meanwhile, the gas flow in micro-channel is decelerated, and the increase in the angle of attack also decelerates the gas flow. In contrast, gas flow in micro-channel is accelerated as free stream incoming Mach number increases. A noteworthy finding is that the rarefaction effects can become very dominant when the free stream incoming Mach number is low. In other words, a free stream with a larger incoming velocity is able to reduce the influence of the rarefaction effects on gas flow in the micro-channel. 展开更多
关键词 rarefied FLOW micro-channel mass FLOW VELOCITY temperature distribution
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CFD simulation of homogeneous reaction characteristics of dehydration of fructose to HMF in micro-channel reactors
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作者 Xin Zhang Hui Liu +1 位作者 Amar Samb Guofeng Wang 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2018年第6期1340-1349,共10页
In this work the applicability of the micro-channel reactor technique to the production of promising platform chemical 5-hydroxymethyl furan(HMF) from fructose in aqueous solution is systemically investigated by perfo... In this work the applicability of the micro-channel reactor technique to the production of promising platform chemical 5-hydroxymethyl furan(HMF) from fructose in aqueous solution is systemically investigated by performing CFD simulations.Influential factors including solvents,residence time distribution of reaction mixtures,heat transfer conditions and micro-channel configurations are evaluated in terms of the reaction performance indices,i.e.,conversion of fructose,HMF selectivity and yield.A scale-up method from a single channel to a multiple channel reactor is also proposed.It is demonstrated that:1) at the single channel scale,controlling residence times and temperature distribution of the reaction mixture within the channel is crucial for enhancing the reaction performance,while different channel configurations lead to marginal improvements;2) for the scaling-up of the reaction process,a reactor module containing 15 circular parallel channels could be used as module blocks,which can be stacked one by one to meet the required reactor performance and production capacity.The present results show that micro-reactors are quite suitable for HMF production. 展开更多
关键词 Fructose dehydration micro-channel reactor SIMULATION OPTIMIZATION
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CFD study of flow-diffusion process in Y-shape micromixer
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作者 陈卓 张睿琦 王晓娜 《Journal of Central South University》 SCIE EI CAS CSCD 2016年第4期969-974,共6页
A CFD simulation was carried out to investigate the mixing process in a Y-shape micromixer with the software Fluent 6.3. The definition of the "diffusion angle" is proposed to describe the molecular diffusio... A CFD simulation was carried out to investigate the mixing process in a Y-shape micromixer with the software Fluent 6.3. The definition of the "diffusion angle" is proposed to describe the molecular diffusion process associated with the flow at low Reynolds number. The linear relationship between the diffusion angle and the Peclet number(Pe) is determined by both theoretical analysis and numerical simulation. Moreover, the simulation results reveal that the diffusion angle is only related to the Peclet number whilst it is irrelevant to the changes of Re(Reynolds number) and Sc(Schmidt number). The range of Peclet number and Reynolds number for experimental measurement are also suggested as Pe≤10000 and Re≤10. 展开更多
关键词 SIMULATION flow-diffusion process molecular diffusion y-shape micromixer
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Flowing simulation of injection molded parts with micro-channel
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作者 崔志香 司军辉 +1 位作者 刘春太 申长雨 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2014年第3期269-276,共8页
In the micro-molding of component with a micro-sized channel, the ability for polymer melt to flowing into the micro-channel in a macro-sized part is a big challenge. The multidimensional flow behaviors are included i... In the micro-molding of component with a micro-sized channel, the ability for polymer melt to flowing into the micro-channel in a macro-sized part is a big challenge. The multidimensional flow behaviors are included in the injection molding the macro-component with a micro-channel. In this case, a simplified model is used to analyze the flow behaviors of the macro-sized part within a micro-channel. The flow behaviors in the macro-cavity are estimated by using the finite element and finite difference methods. The influence of the injection rate, micro-channel size, heat transfer coefficient, and mold temperature on the flowing distance is investigated based on the non-isothermal analytic method. The results show that an increase in the radius of the micro-channel and mold temperature can improve effectively the flowing distance in the micro-channel. 展开更多
关键词 micro-injection molding flowing simulation micro-channel
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Deformation and defects in hydroforming of Y-shaped tubes
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作者 程东明 滕步刚 +1 位作者 郭斌 苑世剑 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2008年第2期206-210,共5页
Hydroforming process of a Y-shaped stainless steel tube was investigated through numerical simulation and experiments. The forming process and reasons of typical defects were analyzed with three different loading path... Hydroforming process of a Y-shaped stainless steel tube was investigated through numerical simulation and experiments. The forming process and reasons of typical defects were analyzed with three different loading paths. Thickness distribution of formed Y-shaped tube was obtained. It is shown by numerical and experimental results that the transition regions are depressed in the forming condition of low inner pressure and wrinkles occur, while fracture occurs in the forming condition of high inner pressure. After forming, the thickness in left transition fillet region is the largest, that in fight transition fillet region is thinner, and the thinnest thickness is at the top of the protrusion. The original thickness line is below the top of the protrusion. The thinning area occurs above this line, while the thickening area is below this line. The maximum thinning rate is significantly increased as the calibration pressure increases, while the maximum thickening rate remains almost unchanged. 展开更多
关键词 HYDROFORMING y-shaped tube loading path DEFECTS thickness
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Flow around three rectangular cylinders arranged in connected and separated Y-shape
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作者 Zhifu Gu Yan Li 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2005年第4期336-341,共6页
Characteristics of cross flow around three rectangular cylinders with two aspect ratios of breadth to width arranged in connected and separated Y-shape at various angles of incident flow were studied by means of force... Characteristics of cross flow around three rectangular cylinders with two aspect ratios of breadth to width arranged in connected and separated Y-shape at various angles of incident flow were studied by means of force measurement in a wind tunnel. Flow visualizations with smoke-wire technique for typical cases were also given. Different types of flow patterns were formed for individual models at different angles of incident flow. From the results of fluctuating velocity measurement in the wake, features of vibration were determined. It shows that as the wind blows along the lines of one limb or rectangular cylinder of the model, oscillation is weak, whereas when the wind blows along the bisector lines of two limbs or cylinders, strong vibration is observed. It is associated with the regular vortex shedding. 展开更多
关键词 Rectangular cylinders. Vortex-induced vibration Flow visualization y-shape
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