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정적 혼합기에서 요변성 유체의 유동 및 혼합 특성에 관한 수치해석
박조은(Jo-Eun Park),강태곤(Tae Gon Kang),문희장(Hee Jang Moon),정선엽(Seon Yeop Jung),박준동(Jun Dong Park) 한국추진공학회 2020 한국추진공학회 학술대회논문집 Vol.2020 No.11
정적 혼합기(Static Mixer)에서 요변성 유체(Thixotropic Fluid)의 유동과 혼합 특성에 대한 수치해석을 수행하였다. 이 연구의 주된 관심사는 요변성 유체의 유변학적 특성이 유동과 혼합에 미치는 영향이다. 요변성 유체의 구조인자를 모사하기 위해 Moore 모델을 채택하였고 요변성 유체의 구조-운동 방정식을 질량보존, 운동량보존식과 결합하여 유한체적법을 이용하여 계산하였다. 본 연구에서는 카오스 혼합을 발생시키기 위해 정적 혼합기를 도입하였다. 요변성 유체의 구조인자 분포와 푸앵카레 단면(Poincaré section)을 이용하여 요변성 유체의 유동 및 혼합 특성을 확인하였다. We conducted numerical simulations on the flow and mixing characteristics of a thixotropic fluid in a static mixer. Our main focus is on the effect of dimensionless parameters on the chaotic mixing of the thixotropic fluid. A Moore model is applied to represent the evolution of structure parameter for the thixotropic fluid. Finite volume method is employed to solve the structure-kinetics equation coupled with the steady Navier-Stokes equation. A groove-embedded partitioned pipe mixer (GPPM), a static mixer based on chaotic advection, is introduced to investigate mixing. Distributions of the structure factor and Poincaré sections are plotted to characterize the flow and mixing affected by the dimensionless number ĸ in laminar flow regime.
1,4-사이클로헥산디온과 1,3-사이클로헥사디온의 혼합비 조절에 의한 BZ 화학적 진동패턴의 변화
허도성,신수범 인제대학교 1998 仁濟論叢 Vol.14 No.1
Belousov-Zhabotinsky에서 두 환원물질의 혼합비율을 조절함으로써 화학적 진동 형태가 달라지는 실험 및 이론적 결과가 소개된다. 일반적으로 사용되는 유기 환원물질인 말론산 대신 사용된 사이클로 헥산디온/BrO3-/Ce4+/H+에 의한 BZ 진동반응에서 1,4-사이클로헥산디온과 1,3-사이클로헥산디온의 초기 혼합비가 조절된다. 혼합시스템의 진동 특징은, 두 환원물질의 전체 농도와 다른 반응물의 농도는 고정된 상태에서 단지 초기 비율 조절에 의해서만 많은 변화를 가져왔다. 계속적으로 반응물을 흘려주는 CSTR 실험에서는 혼합비와 흐름속도의 상호보완적 조절에 의해 복잡한 카오스 진동도 얻어졌다. 중심단어 : BZ 반응, 사이클로헥산디온, 혼합비, 카오스 진동 1,4-cyclohexanedione and 1,3-cyclohexanedione have been used in the oscillation reaction of cyclohexanedione/BrO3-/Ce4+/H+ system. The oscillation dynamics of the mixed substrate system were varied by the mixing ratio of the two substrates under fixed total cyclohexanedione concentration. A complex chaotic oscillations have also been obtained readily by controlling the mixing ratio and the flow rate in CSTR experiments. Computer simulation results have also been obtained by the FKN mechanism of BZ reactions. Key worods : varying, mixing ratio, chaotic oscillations, simulation
강태곤(Tae Gon Kang),최영준(Young Joon Choi),권태헌(Tai Hun Kwon) 대한기계학회 2005 대한기계학회 춘추학술대회 Vol.2005 No.5
Micromixer is one of the important ingredients in many microfluidic systems. In the present work, we aattempt to investigate inertia effect on the flow and mixing performance of three patterned groove micromixers. With these purposes in mind, an efficient numerical scheme called the colored particle tracking method has been employed to analyze the flow and in-depth mixing behavior taking place inside these micromixers. We made use of geometrical periodicity of a micromixer by introducing periodic boundary conditions for the velocity field. From numerical simulations we were able to find out that increasing Reynolds number leaded to the larger rotational motion of fluid and subsequent enhancement in mixing performance. We also numerically visualized the detailed mixing patterns of micromixers of interest
사출 성형된 일회용 카오스 마이크로 믹서의 개발: 나선형 라미네이션 마이크로 믹서 (I) - 디자인 및 수치 해석 -
김동성,이세환,권태헌,Kim Dong Sung,Lee Se Hwan,Kwon Tai Hun,Ahn Chong H. 대한기계학회 2005 大韓機械學會論文集A Vol.29 No.10
The flow in a microchannel is usually characterized as a low Reynolds number (Re) so that good mixing is quite difficult to be achieved. In this regard, we developed a novel chaotic micromixer, named Serpentine Laminating Micromixer (SLM) in the present study, Part 1. In the SLM, the higher level of chaotic mixing can be achieved by combining two general chaotic mixing mechanisms: splitting/recombination and chaotic advection. The splitting and recombination (in other term, lamination) mechanism is obtained by the successive arrangement of 'F'-shape mixing units in two layers. The chaotic advection is induced by the overall three-dimensional serpentine path of the microchannel. Chaotic mixing performance of the SLM was fully characterized numerically. To compare the mixing performance, a T-type micromixer which has the same width, height and length of the SLM was also designed. The three-dimensional numerical mixing simulations show the superiority of the SLM over the T-type micromixer. From the cross-sectional simulation results of mixing patterns, the chaotic advection effect from the serpentine channel path design acts favorably to realize the ideal lamination of fluid flow as Re increases. Chaotic mixing mechanism, proposed in this study, could be easily integrated in Micro-Total-Analysis-System, Lab-on-a-Chip and so on.
논 엘레멘트 믹서의 혼합 메커니즘에 관한 수치해석적 검토
유선호 ( Sun Ho You ) 한국분무공학회 2015 한국액체미립화학회지 Vol.20 No.1
Visualization of the mixing pattern in a non-element mixer was carried out using laser induced fluorescence(LIF) to eval- uate characteristics of mixer consisting of the main flow pipe and branch flow pipes. The branch flows were injected peri- odically with the period Tin normal to the main flow, and rhodamine B was mixed into the most upstream branch flow to visualize mixing pattern in the main flow pipe by LIF. The length of boundary line L of the LIF image was measured. In this study, a numerical analysis was performed to identify the mixing process of the non-element mixer, and the results were compared with experimental results. Each result was almost the same. When the number of branch flows is increased, the mixing pattern became complicated and was supposed to become chaotic. The length of boundary line L increased exponen- tially with an increase in the number of branch flows.
기울어진 그루브 믹서가 고분자 전해질 연료전지 성능에 미치는 영향에 대한 기초연구
윤성찬(S.C. Yun),박재완(J.W. Park),강관형(K.H. Kang) 한국전산유체공학회 2009 한국전산유체공학회 학술대회논문집 Vol.2009 No.11
In the cathode channel of a PEM fuel cell, the local concentration of oxygen near the gas diffusion layer (GDL) decreases in stream wise direction due to chemical reactions, which degrades the efficiency of the oxygen consumption and overall fuel cell efficiency. We numerically studied the influence of the swirling flow generated by a slanted groove mixer (SGM) on the concentration distribution of oxygen. We found that the swirling flow can increase the concentration of oxygen near the GDL, and subsequently improves the oxygen consumption rate.