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Enhancement of liquid-liquid micromixing performance in curved capillary microreactor by generation of Dean vortices
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作者 Shaoyun Wu Zhuang Ma +3 位作者 Zichi Yang Suying Zhao Caijin Zhou Huidong Zheng 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2024年第4期76-82,共7页
Micromixing efficiency is an important parameter for evaluating the multiphase mass transfer performance and reaction efficiency of microreactors.In this work,the novel curved capillary reactor with different shapes w... Micromixing efficiency is an important parameter for evaluating the multiphase mass transfer performance and reaction efficiency of microreactors.In this work,the novel curved capillary reactor with different shapes was designed to generate Dean flow,which was used to enhance the liquid-liquid micromixing performance.The Villermaux-Dushman probe reaction was employed to characterize the micromixing performance in different curved capillary microreactors.The effects of experiment parameters such as liquid flow rate,inner diameter,tube length,and curve diameter on micromixing performance were systematically investigated.Under the optimal conditions,the minimum value of the segmentation factor XS was 0.008.It was worth noting that at the low Reynolds number(Re<30),the change of curved shape on the capillary microreactor can significantly improve the micromixing performance with XS reduced by 37.5%.Further,the correlations of segment index XS with dimensionless factor such as Reynolds number or Dean number were developed,which can be used to predict the liquid-liquid micromixing performance in capillary microreactors. 展开更多
关键词 MICROREACTOR Process intensification micromixing performance Dean flow
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Experimental and numerical investigations on micromixing performance of multi-orifice cross-flow jet mixers
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作者 Hang Yang Zhaojin Lu +4 位作者 Likun Ma Wei Yin Bingjie Wang Zhishan Bai Xiaoyong Yang 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2024年第6期63-72,共10页
Multi-orifice cross-flow jet mixers(MOCJMs)are used in various industrial applications due to their excellent mixing efficiency,but few studies have focused on the micromixing performance of MOCJMs.Herein,the flow cha... Multi-orifice cross-flow jet mixers(MOCJMs)are used in various industrial applications due to their excellent mixing efficiency,but few studies have focused on the micromixing performance of MOCJMs.Herein,the flow characteristics and micromixing performance inside the MOCJM were investigated using experiments and computational fluid dynamics(CFD)simulations based on the Villermaux/Dushman system and the finite-rate/modified eddy-dissipation model.The optimal A value was correlated with the characteristic parameters of MOCJMs to develop a CFD calculation method applicable to the study of the micromixing performance of the MOCJMs.Then the micromixing efficiency was evaluated using the segregation index XS,and the effects of operational and geometric parameters such as mixing flow Reynolds number(ReM),flow ratio(RF),total jet area(ST),the number of jet orifices(n),and outlet configuration on the micromixing efficiency were investigated.It was found that the intensive turbulent region generated by interactions between jets,as well as between jets and crossflows,facilitated rapid reactions.XS decreased with increasing ReM and decreasing RF.Furthermore,MOCJMs with lower ST,four jet orifices,and the narrower outlet configuration demonstrated a better micromixing efficiency.This study contributes to a deeper understanding of the micromixing performance of MOCJMs and provides valuable guidance for their design,optimization,and industrial application. 展开更多
关键词 Multi-orifice cross-flow jet mixer micromixing performance Finite-rate/modified eddy dissipation model Computational fluid dynamics Villermaux/Dushman reaction
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An efficient microreactor with continuous serially connected micromixers for the synthesis of superparamagnetic magnetite nanoparticles 被引量:2
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作者 Wenting Fan Fang Zhao +2 位作者 Ming Chen Jian Li Xuhong Guo 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2023年第7期85-91,共7页
A new microreactor with continuous serially connected micromixers(CSCM)was tailored for the coprecipitation process to synthesize Fe_(3)O_(4) nanoparticles.Numerical simulation reveals that the two types of CSCM micro... A new microreactor with continuous serially connected micromixers(CSCM)was tailored for the coprecipitation process to synthesize Fe_(3)O_(4) nanoparticles.Numerical simulation reveals that the two types of CSCM microchannels(V-typed and U-typed)proposed in this work exhibited markedly better mixing performances than the Zigzag and capillary microchannels due to the promotion of Dean vortices.Complete mixing was achieved in the V-typed microchannel in 2.7 s at an inlet Reynolds number of 27.Fe_(3)O_(4) nanoparticles synthesized in a planar glass microreactor with the V-typed microchannel,possessing an average size of 9.3 nm and exhibiting superparamagnetism,had obviously better dispersity and uniformity and higher crystallinity than those obtained in the capillary microreactor.The new CSCM microreactor developed in this work can act as a potent device to intensify the synthesis of similar inorganic nanoparticles via multistep chemical precipitation processes. 展开更多
关键词 MICROREACTOR Continuous serially connected micromixers MIXING Nanoparticles
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带伴流的合成气微混火焰特性研究
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作者 刘海清 吕亚锦 +3 位作者 张林瑶 邢畅 刘栗 邱朋华 《新能源进展》 CSCD 北大核心 2024年第2期117-123,共7页
选用等体积比的CO和H_(2)合成气为燃料,研究伴流微混单喷嘴的火焰结构。在Fluent平台上,采用稳态不可压的N-S方程进行求解,探究不同出口流速和当量比对微混单喷嘴火焰结构的影响。结果表明:OH的分布与高温区域基本重合,且化学反应释热率... 选用等体积比的CO和H_(2)合成气为燃料,研究伴流微混单喷嘴的火焰结构。在Fluent平台上,采用稳态不可压的N-S方程进行求解,探究不同出口流速和当量比对微混单喷嘴火焰结构的影响。结果表明:OH的分布与高温区域基本重合,且化学反应释热率与OH高浓度区域相一致。随当量比增加,空气侧流速降低,火焰前缘逐渐相连,最终火焰附着在喷嘴出口;喷嘴出口流速的增加则强化了射流夹带作用,使其携带环境中的HO_(2)和O_(2),迅速将H氧化为OH,从而收缩反应区域厚度;伴流作用促进CO氧化生成HCO的过程,降低主燃火焰向环境散热。 展开更多
关键词 微混燃烧 伴流 合成气
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颗粒体系的多尺度混合指数
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作者 徐嘉宇 陈飞国 +1 位作者 徐骥 葛蔚 《化工学报》 EI CSCD 北大核心 2024年第6期2214-2221,共8页
对颗粒混合物均匀性的系统研究揭示了混合过程中显著的多尺度特征,特别是宏尺度上均匀的混合物在微尺度上可能表现为极度不均匀,反之亦然,同时采用不同的采样方法和混合指数表征同一混合物在同一尺度下的均匀性可能也会有所差异。尝试... 对颗粒混合物均匀性的系统研究揭示了混合过程中显著的多尺度特征,特别是宏尺度上均匀的混合物在微尺度上可能表现为极度不均匀,反之亦然,同时采用不同的采样方法和混合指数表征同一混合物在同一尺度下的均匀性可能也会有所差异。尝试提出一种多尺度混合指数,即在不同尺度采用不同评价方法,并将混合指数表达为不同尺度上的分布,而不是在未定义尺度上的单一值。该多尺度表征方法可更精确与全面地反映混合物的均匀特性。 展开更多
关键词 颗粒体系 混合 多尺度 离散单元法 莱西指数 相对标准偏差 宏尺度混合 微尺度混合
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Process and performance of DAAF microspheres prepared by continuous integration from synthesis to spherical coating based on microfluidic system
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作者 Bidong Wu Jiahui Shi +5 位作者 Mengsen Wei Rui Zhu Yi Liu Jinqiang Zhou Chongwei An Jingyu Wang 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第2期629-643,共15页
In order to improve the energy output consistency of 3, 3’-diamino-4, 4’-azoxyfurazan(DAAF) in the new insensitive booster and the safety and efficiency in the preparation process, a continuous preparation system of... In order to improve the energy output consistency of 3, 3’-diamino-4, 4’-azoxyfurazan(DAAF) in the new insensitive booster and the safety and efficiency in the preparation process, a continuous preparation system of DAAF from synthesis to spherical coating was designed and established in this paper, which combined ultrasonic micromixing reaction with microdroplet globular template. In the rapid micromixing stage, the microfluidic mixing technology with ultrasonic was used to synergistically strengthen the uniform and rapid mass transfer mixing reaction between raw materials to ensure the uniformity of DAAF particle nucleation-growth, and to prepare high-quality DAAF crystals with uniform structure and morphology and concentrated particle size distribution. In the microdroplet globular template stage, the microfluidic droplet technology was used to form a droplet globular template with uniform size under the shear action of the continuous phase of the dispersed phase solution containing DAAF particles and binder. The size of the droplet template was controlled by adjusting the flow rate ratio between the continuous phase and the dispersed phase. In the droplet globular template, with the diffusion of the solvent in the dispersed phase droplets, the binder precipitates to coat the DAAF into a ball, forming a DAAF microsphere with high sphericity, narrow particle size distribution and good monodispersity. The problem of discontinuity and DAAF particle suspension in the process was solved, and the coating theory under this process was studied. DAAF was coated with different binder formulations of fluororubber(F2604), nitrocellulose(NC) and NC/glycidyl azide polymer(GAP), and the process verification and evaluation of the system were carried out. The balling effects of large, medium and small droplet templates under different binder formulations were studied. The scanning electron microscope(SEM) results show that the three droplet templates under the three binder formulations exhibit good balling effect and narrow particle size distribution. The DAAF microspheres were characterized by powder X-ray diffraction(XRD), differential scanning calorimetry(DSC), thermo-gravimetric(TG) and sensitivity analyzer. The results showed that the crystal structure of DAAF did not change during the process, and the prepared DAAF microspheres had lower decomposition temperature and lower mechanical sensitivity than raw DAAF. The results of detonation parameters show that the coating of DAAF by using the above three binder formulations will not greatly reduce the energy output of DAAF, and has comparable detonation performance to raw DAAF. This study proves an efficient and safe continuous system from synthesis to spherical coating modification of explosives, which provides a new way for the continuous, safe and efficient preparation of spherical explosives. 展开更多
关键词 DAAF micromixing technology Microdroplet technology SYNTHESIS Spherical coating Continuousization
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无源微混合器研究进展
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作者 谢煜 田旺 +1 位作者 张杨 秦康 《现代化工》 CAS CSCD 北大核心 2024年第5期82-87,共6页
介绍了基于层压的微混合器、基于障碍物的微混合器、基于收敛-发散的微混合器和基于弯曲通道的微混合器等4种主要的无源微混合器研究进展,深入分析了各自的结构特点、混合特性、优缺点及适宜的应用场景。在此基础上,对无源微混合器的主... 介绍了基于层压的微混合器、基于障碍物的微混合器、基于收敛-发散的微混合器和基于弯曲通道的微混合器等4种主要的无源微混合器研究进展,深入分析了各自的结构特点、混合特性、优缺点及适宜的应用场景。在此基础上,对无源微混合器的主要制造技术进行了归纳,未来3D打印等新型增材制造技术的发展将会高效赋能微流控元件的大规模制造和集成化应用。最后展望了无源微混合器的发展方向。 展开更多
关键词 无源微混合器 微尺度 多相流 应用场景 制造
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Micromixing in the Submerged Circulative Impinging Stream Reactor 被引量:20
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作者 伍沅 肖杨 周玉新 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2003年第4期420-425,共6页
Micromixing in the submerged circulative impinging stream reactor (SCISR) developed by the authors is investigated with the Bourne's reaction scheme. The values measured for the impinging velocity, u0, under the ... Micromixing in the submerged circulative impinging stream reactor (SCISR) developed by the authors is investigated with the Bourne's reaction scheme. The values measured for the impinging velocity, u0, under the conditions of SCISR normal operation, only is of the order of 0.1m·s^-1, are much slower than that inferred,suggesting low power requirement for operation. The values of the characteristic time constant for micromixing,tM, determined in the impinging velocity range of 0.184m·s^-1 < u0 < 0.326m·s^-1 are ranged from 192ms to 87 ms, showing that impinging streams promotes micromixing very efficiently. The data follow approximately the relationship of tM∝ u0^-1.5. A comparative study shows that the micromixing performance of SCISR is much better than that of the traditional stirred tank reactor. The tM values predicted with the existing theoretical model are systematically longer than those measured by about 2--3 times, implying that the regularity of impinging streams promoting micromixing is unclear yet. 展开更多
关键词 micromixING impinging streams REACTOR
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CFD and experimental investigations on the micromixing performance of single countercurrent-flow microchannel reactor 被引量:3
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作者 Kunpeng Cheng Chunyu Liu +1 位作者 Tianyu Guo Lixiong Wen 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2019年第5期1079-1088,共10页
Microchannel reactors are widely used in different fields due to their intensive micromixing and, thus, high masstransfer efficiency. In this work, a single countercurrent-flow microchannel reactor(S-CFMCR) at the siz... Microchannel reactors are widely used in different fields due to their intensive micromixing and, thus, high masstransfer efficiency. In this work, a single countercurrent-flow microchannel reactor(S-CFMCR) at the size of ~1 mm was developed by steel micro-capillary and laser drilling technology. Utilizing the Villermaux/Dushman parallel competing reaction, numerical and experimental studies were carried out to investigate the micromixing performance(expressed as the segregation index XS) of liquids inside S-CFMCR at the low flow velocity regime.The effects of various operating conditions and design parameters of S-CFMCR, e.g., inlet Reynolds number(Re),volumetric flow ratio(R), inlet diameter(d) and outlet length(L), on the quality of micromixing were studied qualitatively. It was found that the micromixing efficiency was enhanced with increasing Re, but weakened with the increase of R. Moreover, d and L also have a significant influence on micromixing. CFD results were in good agreement with experimental data. In addition, the visualization of velocity magnitude, turbulent kinetic energy and concentration distributions of various ions inside S-CFMCR was illustrated as well. Based on the incorporation model, the estimated minimum micromixing time tmof S-CFMCR is ~2 × 10-4s. 展开更多
关键词 SINGLE countercurrent-flow MICROCHANNEL REACTOR micromixING performance CFD Villermaux/Dushman reaction
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Effects of Magnetic Particles Entrance Arrangements on Mixing Efficiency of a Magnetic Bead Micromixer 被引量:4
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作者 Reza Kamali Seyed Alireza Shekoohi Alireza Binesh 《Nano-Micro Letters》 SCIE EI CAS 2014年第1期30-37,共8页
In this study, a computer code is developed to numerically investigate a magnetic bead micromixer under different conditions. The micromixer consists of a microchannel and numerous micro magnetic particles which enter... In this study, a computer code is developed to numerically investigate a magnetic bead micromixer under different conditions. The micromixer consists of a microchannel and numerous micro magnetic particles which enter the micromixer by fluid flows and are actuated by an alternating magnetic field normal to the main flow. An important feature of micromixer which is not considered before by researchers is the particle entrance arrangement into the micromixer. This parameter could effectively affect the micromixer efficiency. There are two general micro magnetic particle entrance arrangements in magnetic bead micromixers: determined position entrance and random position entrance. In the case of determined position entrances, micro magnetic particles enter the micromixer at specific positions of entrance cross section. However, in a random position entrance,particles enter the microchannel with no order. In this study mixing efficiencies of identical magnetic bead micromixers which only differ in particle entrance arrangement are numerically investigated and compared.The results reported in this paper illustrate that the prepared computer code can be one of the most powerful and beneficial tools for the magnetic bead micromixer performance analysis. In addition, the results show that some features of the magnetic bead micromixer are strongly affected by the entrance arrangement of the particles. 展开更多
关键词 Magnetic bead micromixer Mixing efficiency Particle entrance arrangement
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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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Numerical simulation on micromixer based on synthetic jet 被引量:1
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作者 Minghou Liu Chen Xie Xiangfeng Zhang Yiliang Chen 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2008年第6期629-636,共8页
This paper studied a concept of micromixer with a synthetic jet placed at the bottom of a rectangular channel. Due to periodic ejections from and suctions into the channel, the fluids are mixed effectively. To study t... This paper studied a concept of micromixer with a synthetic jet placed at the bottom of a rectangular channel. Due to periodic ejections from and suctions into the channel, the fluids are mixed effectively. To study the effects of the inlet velocity, the jet intensity and frequency, and the jet location on the mixing efficiency, 3-D numerical simulations of the micromixer have been carried out. It has been found that when the jet intensity and the frequency are fixed, the mixing efficiency increases when Re 〈 50, and decreases when Re 〉 50 with the best mixing efficiency achieved at Re = 50. When the ratio of the jet velocity magnitude to the inlet velocity is taken as 10 and the jet frequency is 100 Hz, the mixing index reaches the highest value. It has also been found that to get better mixing efficiency, the orifice of the synthetic jet should be asymmetrically located away from the channel's centerline. 展开更多
关键词 micromixER Synthetic jet Mixing index
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Micromixing efficiency in a T-shaped confined impinging jet reactor 被引量:3
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作者 高正明 韩敬 +1 位作者 包雨云 李志鹏 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2015年第2期350-355,共6页
Confined impinging jet reactor(CIJR)offers advantages for chemical rapid processes and has become an important new reactor used in the chemical industry.The micromixing efficiency in a T-shaped CIJR for two tubes of i... Confined impinging jet reactor(CIJR)offers advantages for chemical rapid processes and has become an important new reactor used in the chemical industry.The micromixing efficiency in a T-shaped CIJR for two tubes of inner diameter of 3 mm was studied by using a parallel competing iodide–iodate reaction as the working system.In this work,the effects of different operating conditions,such as impinging velocity and acid concentration,on segregation index were investigated.In addition,the effects of the inner nozzles diameter and the distance L between the jet axis and the top wall of the mixing chamber on the micromixing efficiency were also considered.It is concluded that the best range of L in this CIJR is 6.5–12.5 mm.Based on the incorporation model,the estimated minimum micromixing time tmof CIJR approximately equals to 2×10-4s.These experimental results indicate clearly that CIJR possesses a much better micromixing performance compared with the conventional stirred tank(micromixing time of 2×10-3to 2×10-2s).Hence,it can be envisioned that CIJR has more promising applications in various industrial processes. 展开更多
关键词 Impinging jet reactor micromixING Segregation index Incorporation model
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Computational Fluid Dynamic Simulation of Liquid-Liquid Mixing in a Static Double-T-shaped Micromixer 被引量:1
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作者 Elmabruk A. MANSUR 王运东 戴猷元 《过程工程学报》 EI CAS CSCD 北大核心 2008年第6期1080-1084,共5页
The laminar flow structure and mixing performance of T-shaped and double-T-shaped micromixers with rectangular cross-section have been investigated using computational fluid dynamic (CFD) simulation. FLUENT software i... The laminar flow structure and mixing performance of T-shaped and double-T-shaped micromixers with rectangular cross-section have been investigated using computational fluid dynamic (CFD) simulation. FLUENT software is used to evaluate the mixing efficiency. The numerical simulation results show that the presented double-T-micromixer is highly efficient over T-shaped micromixer. The performance of double-T-micromixer with and without static mixing elements (SME) is also investigated. The enhancement in mixing performance is thought to be caused by the generation of eddies and lateral velocity component when the mixture flows through these elements. Mixing efficiency as higher as 97% is reached within a mixing length of 320 μm downstream from the first T-junction with the enhancement of three SMEs. 展开更多
关键词 计算方法 流体动力学 模拟方法 液液混合 双T形微混合器 物理过程
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Micromixing characteristics in a gas-liquid-solid stirred tank with settling particles 被引量:3
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作者 栗万博 耿兴业 +1 位作者 包雨云 高正明 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2015年第3期461-470,共10页
The parallel-competing iodide-iodate reaction scheme was used to study the micromixing performance in a multi-phase stirred tank of 0.3 m diameter.The impeller combination consisted of a half elliptical blade disk tur... The parallel-competing iodide-iodate reaction scheme was used to study the micromixing performance in a multi-phase stirred tank of 0.3 m diameter.The impeller combination consisted of a half elliptical blade disk turbine below two down-pimping wide-blade hydrofoils,identified as HEDT + 2WH_D.Nitrogen and glass beads of100 μm diameter and density 2500 kg-m^(-3) were used as the dispersed phases.The micromixing could be improved by sparging gas because of its additional potential energy.Also,micromixing could be improved by the solid particles with high kinetic energy near the impeller tip.In a gas-solid-liquid system,the gas-liquid film vibration with damping,due to the frequent collisions between the bubbles and particles,led to the decrease of the turbulence level in the liquid and caused eventually the deterioration of the micromixing.A Damping Film Dissipation model is formulated to shed light on the above micromixing performances.At last,the micromixing time t_m according to the incorporation model varied from 1.9 ms to 6.7 ms in our experiments. 展开更多
关键词 Stirred tank Gas-liquid-solid micromixing performance Incorporation model
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Novel Micromixer with Complex 3D-Shape Inner Units: Design, Simulation and Additive Manufacturing 被引量:1
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作者 Di Wang Guangzhao Ye +5 位作者 Jingming Mai Xiaomin Chen Yongqiang Yang Yang Li Xiaojun Chen Jie Chen 《Computer Modeling in Engineering & Sciences》 SCIE EI 2020年第6期1061-1077,共17页
In this paper,a novel micromixer with complex 3D-shape inner units was put forward and fabricated by metal Additive Manufacturing(AM).The design of the micromixer combined the constraints of selective laser melting te... In this paper,a novel micromixer with complex 3D-shape inner units was put forward and fabricated by metal Additive Manufacturing(AM).The design of the micromixer combined the constraints of selective laser melting technology and the factors to improve mixing efficiency.Villermaux-Dushman reaction system and Compute Fluid Design(CFD)simulation were conducted to investigate the performance and the mechanism of this novel micromixer to improve mixing efficiency.The research found that the best mixing efficiency of this novel micromixer could be gained when the inner units divided fluid into five pieces with a uniform volume.Compared with a conventional micromixer without obstacle in the channel,the micromixer designed in this research achieved higher mixing efficiency and reduce the pressure drop by 10.34%.The mixing behaviour in this novel micromixer was discussed,which mainly contains two types:collisions and swirls.Via collisions,the fluid micro masses would hit each other directly,which broke the boundaries of micro masses and promoted the interchange of species in the whole flow field.In swirls,the fluid micro masses were drawn into thin and long slices,which increased the size of the contact area and enhanced molecule diffusion.Finally,the application scheme of this novel micromixer was briefly discussed. 展开更多
关键词 Additive manufacturing(AM) micromixER computational fluid dynamics(CFD) selective laser melting(SLM)
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CFD study of non-premixed swirling burners: Effect of turbulence models 被引量:1
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作者 Erfan Khodabandeh Hesam Moghadasi +4 位作者 Mohsen Saffari Pour Mikael Ersson Par G.Jonsson Marc A.Rosen Alireza Rahbari 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2020年第4期1029-1038,共10页
This research investigates a numerical simulation of swirling turbulent non-premixed combustion.The effects on the combustion characteristics are examined with three turbulence models:namely as the Reynolds stress mod... This research investigates a numerical simulation of swirling turbulent non-premixed combustion.The effects on the combustion characteristics are examined with three turbulence models:namely as the Reynolds stress model,spectral turbulence analysis and Re-Normalization Group.In addition,the P-1 and discrete ordinate(DO)models are used to simulate the radiative heat transfer in this model.The governing equations associated with the required boundary conditions are solved using the numerical model.The accuracy of this model is validated with the published experimental data and the comparison elucidates that there is a reasonable agreement between the obtained values from this model and the corresponding experimental quantities.Among different models proposed in this research,the Reynolds stress model with the Probability Density Function(PDF)approach is more accurate(nearly up to 50%)than other turbulent models for a swirling flow field.Regarding the effect of radiative heat transfer model,it is observed that the discrete ordinate model is more precise than the P-1 model in anticipating the experimental behavior.This model is able to simulate the subcritical nature of the isothermal flow as well as the size and shape of the internal recirculation induced by the swirl due to combustion. 展开更多
关键词 Computational Fluid Dynamics(CFD) Turbulent combustion non-premixed flames Large eddy simulations Radiative heat transfer model Modeling validation
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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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Micromixing of a Two Phase System in a Stirred Tank with Multiple Impellers
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作者 Lei Yang Jingcai Cheng +1 位作者 Ping Fan Chao Yang 《Advances in Materials Physics and Chemistry》 2012年第4期150-153,共4页
The competitive iodide/iodate reaction scheme was used to ascertain the micromixing in the stirred solid-liquid systems. Two different glass beads from 450 to 1250 μm were tested. The effect of solid particles on rea... The competitive iodide/iodate reaction scheme was used to ascertain the micromixing in the stirred solid-liquid systems. Two different glass beads from 450 to 1250 μm were tested. The effect of solid particles on reaction selectivity with multiple impellers at different feed points has been investigated. It was confirmed that glass beads as a second phase were suitable for the study. The segregation index has changed significantly only for the medium-sized particles at relatively high solid holdups. The cloud formation was clearly observed for the medium-sized particles at a concentration of 12.12 wt. %. When feeding into the clear liquid above the cloud, the value of the segregation index increased significantly. However, in the presence of particles of 1-1.25 mm, the influence on the selectivity was negligible when the agitation speed was increased. 展开更多
关键词 micromixING PARALLEL REACTIONS Two PHASES Multiple IMPELLERS
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Mixing Dynamics and Synthesis Performance of Staggered Herringbone Micromixer for Limit Size Lipid Nanoparticles
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作者 Shuai Zhang Yunlong Fan +4 位作者 Chenmu Xue Yuanzhan Yang Xiaoqiong Li Xiaodong Chen Yulin Deng 《Journal of Beijing Institute of Technology》 EI CAS 2022年第3期293-301,共9页
Staggered herringbone micromixer has shown good efficiency of mixing and performance of synthesizing nanoparticles.To bring a detailed understanding of the mixing dynamics and syn-thesis performance of this kind of mi... Staggered herringbone micromixer has shown good efficiency of mixing and performance of synthesizing nanoparticles.To bring a detailed understanding of the mixing dynamics and syn-thesis performance of this kind of micromixer,this paper carries out a high-fidelity numerical simu-lation and a parametrial experimental study on a well-established design.A passive tracer is induced in the numerical simulation to analyze mixing dynamics induced by the staggered herring-bone structures.Three effects are identified to reveal the underlying mechanisms,including folding,stretching,and splitting.To the authors’knowledge,the splitting effect is identified for the first time by the isosurface of the passive tracer,to show the high efficiency of the staggered herring-bone design.The micromixer is then used to synthesize lipid nanoparticles by mixing a mixture of lipid and poly(lactic-co-glycolic acid)(PLGA)solutions with deionized water.Under a wide mass ratio of lipid and PLGA solutions,nanoparticles with good monodispersity are synthesized to reflect the good compatibility of the micromixer and the mixture.In addition,an optimized mass ratio is identified from the parametrical experiment. 展开更多
关键词 mixing dynamics staggered herringbone micromixer FOLDING STRETCHING splitting
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