Effects of spherical adsorbent fluidization and self-rotation on removal of VOCs in a cyclonic fluidized bed

Liang Ma,Guolin Xiang,Yuan Huang,Meng-Ya He,Jianping Li,Pengbo Fu 한국공업화학회 2020 Journal of Industrial and Engineering Chemistry Vol.85 No.-

Afluidized bed has the advantages of treating largeflows, intensifying mass and heat transfer, andlowering costs. This study proposed a cyclonicfluidized bed packed with spherical activated carbonadsorbents for volatile organic compounds adsorption. Thefluidization and self-rotation of the ACparticles in a 25 mm cyclonicfluidized bed were studied with high-speed camera testing technology. Theeffects of the particle movement on the adsorption efficiency of toluene were also tested. The resultsshow that most of the particles at the inlet side of the cyclonicfluidized bed were moving up when theinlet airflow rate was greater than 2.0 m3/h. The particles began to move in clusters when the relativepacking height increased to a critical value of 0.57. Increasing the gasflow rate and the diameter andheight of the core column will increase the self-rotation speed of the total particles. The maximum selfrotationspeed of spherical adsorbents reached 1700 rad/s at the inletflow rate of 2.5 m3/h. In the case ofthe same axial velocity of the gas phase in the upper space of the core column, increasing the particle selfrotationspeed can slightly improve the adsorption efficiency. The maximum adsorption efficiencyreached 99% when the inletflow rate is 1.0 m3/h with relative packing height 0.65.

회전하는 알루미늄 환봉의 미세입자 분사가공시 통계적 방법에 의한 분사조건에 대한 연구

권대규(Dae Kyu Kwon),왕덕현(Duck Hyun Wang) 한국기계가공학회 2017 한국기계가공학회지 Vol.16 No.2

An experimental study of micro blasting for a rotating aluminum rod was conducted through the statistical analysis of ANOVA to obtain the effect of blasting conditions. The rotating equipment was designed and constructed with forward and backward moving for helical blasting, but rotation was used in this study. The blasting condition factors were the type of abrasive particle, nozzle diameter, pressure, standoff distance, injection time, etc. The width of the surface, the maximum depth of the sprayed surface, and ANOVA were analyzed by statistical analysis. The results showed that the contributions of the main factors were pressure, nozzle diameter, and injection particle.

미세입자 분사가공용 시퀸스 제어가 가능한 2축 스테이지 개발에 관한 연구

황철웅(Chul-Woong Hwang),이세한(Sea-Han Lee),왕덕현(Duck Hyun Wang) 한국기계가공학회 2020 한국기계가공학회지 Vol.19 No.8

A stable rotational-to-linear motion transformation structure using a driving mechanism with 2 degrees of freedom was developed for an orthogonal mechanism to prevent the interference of each axis in 2D motion. In this mechanism, a step motor was used for precise position control. This structure was developed to maneuver workparts in micro particle blast machining experiments. To determine the real-time performance of micro particle blast machining, the control, input, and output were operated simultaneously and precise position control was implemented, using a timer interrupt with multiple execution codes. The two step motors obtained precise position control by removing backlash with a ball-screw mechanism. The device has menu-type control codes for user-friendliness, and real-time sequence control was simultaneously adopted for user control input.

Total Lagrangian 기반 음해적 입자법을 이용한 외팔보 동적 거동 해석

이완기(Wan Ki Lee),주영석(Young Suk Joo),김진현(Jin Kim) 대한기계학회 2022 大韓機械學會論文集A Vol.46 No.5

SPH(smoothed particle hydrodynamics)는 Lagrangian 기반 수치해석 기법이며 입자를 단위로 사용하는 무격자 방식이다. 기존 SPH 기법으로 구현된 구조해석은 두 가지 문제점을 가지고 있다. 대변형 지점에서 인장불안정으로 인한 입자 겹침 문제와 수치적 민감성으로 인하여 작은 해석간격을 사용하는 문제이다. 본 연구에서는 total Lagrangian 기반 SPH 기법으로 구조해석을 구현하여 인장불안정 문제를 해소한다. 그리고 동회전성 커널함수를 사용하고 탄성력 연산을 음해적으로 수행하여 보다 큰 해석간격을 사용하여도 해석이 발산하지 않도록 한다. 외팔보 동적 거동 해석을 수행하여 수치모델 정확성을 검증하고 구조해석 적용 가능성을 확인한다. Smoothed particle hydrodynamics (SPH) is a particle-based meshless Lagrangian numerical method. The status quo SPH-based structural analysis has two problems: overlapping particles at large deformation points owing to tensile instability and marginal limits on the time-step size owing to the inherent numerical sensitivity. In this study, a total Lagrangian SPH method is employed in the structural analysis to solve the tensile instability problem. In addition, simulation divergence is prevented even when a relatively larger time-step is used by performing a numerical analysis implicitly and using a corotated kernel function. Dynamic analyses of cantilever beams are performed to verify the accuracy of the numerical model presented in this study and its applicability to structure analysis.

Design and Fabrication of CLYC-Based Rotational Modulation Collimator (RMC) System for Gamma-Ray/Neutron Dual-Particle Imager

Kim, Hyun Suk,Lee, Jooyub,Choi, Sanghun,Bang, Young-bong,Ye, Sung-Joon,Kim, Geehyun The Korean Association for Radiation Protection 2021 방사선방어학회지 Vol.46 No.3

Background: This work aims to develop a new imaging system based on a pulse shape discrimination-capable Cs₂LiYCl₆:Ce (CLYC) scintillation detector combined with the rotational modulation collimator (RMC) technique for dual-particle imaging. Materials and Methods: In this study, a CLYC-based RMC system was designed based on Monte Carlo simulations, and a prototype was fabricated. Therein, a rotation control system was developed to rotate the RMC unit precisely, and a graphical user interface-based software was also developed to operate the data acquisition with RMC rotation. The RMC system was developed to allow combining various types of collimator masks and detectors interchangeably, making the imaging system more versatile for various applications and conditions. Results and Discussion: Operational performance of the fabricated system was studied by checking the accuracy and precision of the collimator rotation and obtaining modulation patterns from a gamma-ray source repeatedly. Conclusion: The prototype RMC system showed reliability in its mechanical properties and reproducibility in the acquisition of modulation patterns, and it will be further investigated for its dual-particle imaging capability with various complex radioactive source conditions.

Effect of icosahedral phase particles on the texture evolution in Mg-Zn-Y alloys

Lee, J.Y.,Lim, H.K.,Kim, D.H.,Kim, W.T.,Kim, D.H. Elsevier Sequoia 2008 Materials science & engineering. properties, micro Vol.491 No.1

In order to understand the role of the icosahedral phase (I-phase) particles on the improved mechanical properties of Mg-3Zn-0.6Y and Mg-6Zn-1.2Y alloys, the texture evolution has been investigated by the X-ray diffraction and electron back-scattered diffraction (EBSD) analyses. Mg-6Zn-1.2Y alloy exhibits higher strength than Mg-3Zn-0.6Y alloy due to the presence of larger amount of I-phase particles. However, Mg-6Zn-1.2Y alloy exhibits a larger elongation than Mg-3Zn-0.6Y alloy. With increasing the volume fraction of I-phase particles and rolling speeds, the relatively random texture is developed, which is attributed to local lattice rotations around I-phase particles during shear deformation. The relatively random texture plays an important role in enhancing the ductility when larger amount of I-phase particles are present in Mg-6Zn-1.2Y alloy.

EEPS 및 Cavity 회전형 희석장치의 디젤 입자측정 특성 연구

김홍석(Hongsuk Kim),김진현(Jinhyun Kim),조규백(Gyubaek Cho),정용일(Youngil Jeong) 한국자동차공학회 2004 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-

EEPS is a newly introduced instrument for size distribution measurement of engine exhaust particles. It can measure nano-particles with an adequate resolution and in real time. In this study, the characteristics of EEPS were compared with ELPI and SMPS. EEPS showed a same effect of engine load on the size distribution with ELPI and SMPS. But the quantitative results of EEPS were more similar to SMPS than ELPI, because the EEPS and SMPS use a same principle for classifying particles by size. The capability for transient measurement of EEPS was equivalent to that of ELPI. Additionally, the effects of dilution ratio and heating the dilution gas on the size distribution ofthe diesel particles were studied using a rotating cavity type diluter.

Numerical analysis of internal flow and mixing performance in polymer extruder II: Twin screw element

김낙수,이재욱,김홍범 한국유변학회 2006 Korea-Australia rheology journal Vol.18 No.3

We analyzed the non-Newtonian and non-isothermal flow with Carreau-Yasuda viscosity model in co-rotating and counter-rotating twin screw extruder systems. The mixing performances with respect to the screw speed, the screw pitch, and the rotating direction have been investigated. The dynamics of mixing was studied numerically by tracking the motions of particles. The extent of mixing was characterized in terms of the deformation rate, the residence time distribution, and the average strain. The results showed that the high screw speed decreases the residence time but increases the deformation rate. Small screw pitch increases the residence time. It is concluded that the high screw speed increases the dispersive mixing performance, while the small screw pitch increases the distributive mixing performance. Co-rotating screw extruder has the better conveying performance and the distributive mixing performance than counter-rotating screw extruder with the same screw speed and pitch. Co-rotating screw extruder developed faster transport velocity and it is advantageous the flow characteristics to the mixing that transfers polymer melt from one barrel to the other barrel.

Numerical analysis of internal flow and mixing performance in polymer extruder II: twin screw element

Kim, Nak-Soo,Kim, Hong-Bum,Lee, Jae-Wook The Korean Society of Rheology 2006 Korea-Australia rheology journal Vol.18 No.3

We analyzed the non-Newtonian and non-isothermal flow with Carreau-Yasuda viscosity model in co-rotating and counter-rotating twin screw extruder systems. The mixing performances with respect to the screw speed, the screw pitch, and the rotating direction have been investigated. The dynamics of mixing was studied numerically by tracking the motions of particles. The extent of mixing was characterized in terms of the deformation rate, the residence time distribution, and the average strain. The results showed that the high screw speed decreases the residence time but increases the deformation rate. Small screw pitch increases the residence time. It is concluded that the high screw speed increases the dispersive mixing performance, while the small screw pitch increases the distributive mixing performance. Co-rotating screw extruder has the better conveying performance and the distributive mixing performance than counter-rotating screw extruder with the same screw speed and pitch. Co-rotating screw extruder developed faster transport velocity and it is advantageous the flow characteristics to the mixing that transfers polymer melt from one barrel to the other barrel.

Particle Cracking and Rotation during Plastic Deformation of 7075 Aluminum Alloy

이순기 대한금속·재료학회 2009 METALS AND MATERIALS International Vol.15 No.4

The utility of a novel digital image processing technique for automatic detection and separation of cracked constituent particles was applied to quantitatively characterize the microstructural damage on Fe-rich intermetallic particles that were cracked in a 7075 Al-alloy. This cracking of the Fe-rich intermetallic particles was due to a function of strain under uniaxial tension, compression, and torsion. The comparison of the data on the strained samples revealed that at tensile strain, the number fraction of the cracked Fe-rich particles was significantly higher than those at torsion while the compression strains and the average volume of the cracked Fe-rich particles increased when the strain increased. The percentage-cracked particles had a linear relationship with all of the strains for all of the loading conditions. Significant rotations of Fe-rich intermetallic particles occurred during the deformation of this alloy under torsion. These rotations tended to align themselves along the direction of applied/induced tensile stretch, which in turn affected the progression of damage due to particle cracking. The utility of a novel digital image processing technique for automatic detection and separation of cracked constituent particles was applied to quantitatively characterize the microstructural damage on Fe-rich intermetallic particles that were cracked in a 7075 Al-alloy. This cracking of the Fe-rich intermetallic particles was due to a function of strain under uniaxial tension, compression, and torsion. The comparison of the data on the strained samples revealed that at tensile strain, the number fraction of the cracked Fe-rich particles was significantly higher than those at torsion while the compression strains and the average volume of the cracked Fe-rich particles increased when the strain increased. The percentage-cracked particles had a linear relationship with all of the strains for all of the loading conditions. Significant rotations of Fe-rich intermetallic particles occurred during the deformation of this alloy under torsion. These rotations tended to align themselves along the direction of applied/induced tensile stretch, which in turn affected the progression of damage due to particle cracking.