마랑고니 효과를 이용한 마이크로 채널 내의 액적 제어

원준(June Won),송시몬(Simon Song) 대한기계학회 2012 대한기계학회 춘추학술대회 Vol.2012 No.11

Controlling droplets is one of the most essential techniques in lab-on-a-chip development. Especially, using local surface tension gradient around a droplet, called Marangoni effects, is paid attention recently as a facile and versatile approach. The Marangoni effect can be induced by light illumination using laser to around a droplet and consequent local temperature gradient. In this research we focus on the effects of various flow conditions and environments on Marangoni effects. The main goal is to establish the most suitable conditions such as droplet size and light intensity, flow rate and etc. A T-junction microchannel was used for hexadecane droplet generation. A green laser was chosen as a light source and a dark ink was used as a continuous phase to absorb the light. Preliminary results shows that a moving droplet in a microchannel can be trapped locally or deflected its direction by properly controlling the flow rate and designing flow geometry.

Wafer 건조공정의 Marangoni Effect와 Watermark현상이 부적합품 발생에 미치는 영향연구

함관우,김광수 한국품질경영학회 2018 한국품질경영학회 학술대회 Vol.2018 No.-

본 연구는 Marangoni Effect를 활용한 Wafer 표면의 건조와 그 이면의 Watermark 현상이 부적합품 발생에 미치는 영향에 대한 고찰을 통해 최적화된 건조 공정의 조건을 제시하는데 그 목적을 두었다. H사 해당 공정 기술 그룹의 부서 KPI로 부적합품률 목표 1,500ppm으로 설정하였고 Dry 공정이 진행되는 Apet Dryer Unit內 사용 약액은 IPA와 초순수로 규정하되 Recipe Tuning 및 Hardware Modify는 가능토록 조건을 부여하여 사례를 설계하였다. Watermark 발생요인을 4M 분석을 통해 계통적 요인의 관계규정과 동시에 참 원인을 발굴하였고 개선안에 대한 MPH 영향 및 시급성, 해결성, 효과성을 초점으로 연구를 진행하였다. Wafer 상승時 초순수 유량에 따른 Watermark 발생과 반응표면 분석을 통한 최적 영역을 도출하였고 Wafer 상승 속도와 Marangoni Effect의 상관 관계를 통해 부적합품 발생 원인을 규명하였다. 그 결과, 상승 Position-1, 2의 Speed 최적화를 통해 부적합품률 3,429ppm → 1,366ppm 감소로 목표 달성하였으며 고장시간 평균 452분 → 19분으로 95.8% 감소하며 생산성 증대에도 기여하였다. 이는 Marangoni Effect 극대화와 Watermark 발생 관계를 정량적으로 규명하여 최적의 공정 조건을 구축하였으며 Wafer Device 별 확대 적용이 가능하단 시사점을 제시하였다.

수직 진동을 이용한 가열된 고체표면 위 증발하는 액적의 내부유동 제어연구

박창석(Chang-Seok Park),임희창(Hee-Chang Lim) 대한기계학회 2017 大韓機械學會論文集B Vol.41 No.1

가열된 표면에서의 액적은 일반적으로 내부에 마랑고니 유동이 발생하고, 이는 불균일한 침전물 패턴 형상을 구성하게 된다. 본 연구는 마랑고니 유동을 가시화하고, 수직진동을 사용해서 이를 제어하는 것을 주 목적으로 한다. 액적이 증발하는 동안, 액적의 접촉각 변화와 부피변화를 실험적으로 알 수 있었고, PIV(Particle Image Velocimetry) 실험 장치를 이용하여, 평판 온도별 마랑고니 유동의 내부 유동의 흐름을 가시화하였다. 그리고 평판에 각 주파수별 수직진동을 가해주는 실험을 진행하여, 그 결과 마랑고니 유동의 유동 방향과 수직진동의 유동 방향이 서로 반대인 것을 확인할 수 있었다. 마지막으로 증발하는 액적에 수직진동을 가해줌으로써, 액적의 하단부분에서 내부유동의 흐름변화를 관찰하였다. 마랑고니유동에 의해 발생하는 내부유동 방향과 수직진동으로 발생하는 내부유동의 방향이 서로 반대 방향이므로 가열된 평판에 진동을 가해주었을 때 액적 내부유동의 흐름이 변화가 발생하였고, 이는 곧 불균일한 침전물 패턴이 억제된 것을 증발 후 침전물의 패턴형상을 통해 확인할 수 있었다. Thermal Marangoni flow has been observed inside droplets on heated surfaces, finally resulting in a coffee stain effect. This study aims to visualize and control the thermal Marangoni flow by employing periodic vertical vibration. The variations in the contact angle and internal volume of the droplet as it evaporates is observed by using a combination of continuous light and a still camera. With regard to the internal velocity, the particle image velocimetry system is applied to visualize the internal thermal Marangoni flow. In order to estimate the internal temperature gradient and surface tension on the surface of a droplet, the theoretical model based on the conduction and convection theory of heat transfer is applied. Thus, the internal velocity increases with an increase in plate temperature. The flow directions of the Marangoni and gravitational flows are opposite, and hence, it may be possible to control the coffee stain effect.

액적증발 침착패턴 형성에 미치는 계면활성제의 효과

정나리나(Narina Jung),서해원(Hae Won Seo),김필원(Pilwon Kim),유춘상(Chun Sang Yoo) 대한기계학회 2015 대한기계학회 춘추학술대회 Vol.2015 No.11

Evaporation of a colloidal droplet typically leaves ring-like deposit patterns on a substrate, now well-known as the coffee ring effect. We investigate the effect of surfactants on the deposit formation in a drying droplet. A coarse grained model has been developed to simulate kinetics of surfactants, and the related deposit formation at the contact line. The model can successfully generate stable surfactant-induced Marangoni eddies which shows a good agreement with recently-reported experiments. We show that adsorption rate and electrostatic repulsion are key factors to generate Marangoni eddies. The effects of surfactants are further investigated by systematically varying adsorption rates, strengths of repulsion, and initial concentrations of surfactants.

Passive micromixer using by convection and surface tension effects with air-liquid interface

주종일,Jay Warrick 한국바이오칩학회 2013 BioChip Journal Vol.7 No.4

This article describes a passive micromixer that utilizes an air-liquid interface and surface tension effects to enhance fluid mixing via convection and Marangoni effects. Performance of the microfluidic component is tested within a passive-pumpingbased device that consists of three microchannels connected in succession using passive micro-mixers. Mixing was quantified at 5 key points along the length of the device using microscope images of patterned streams of Alexa 488 fluorescent-dyed water and pure DI water flowing through the device. The passive micro-mixer mixed fluid 15-20 times more effectively than diffusion between laminar flow streams alone and is a novel micro-mixer embodiment that provides an additional strategy for removing external components from microscale devices for simpler, autonomous operation.

Enhanced mass transfer rate and solubility of methane via addition of alcohols for Methylosinus trichosporium OB3b fermentation

Kim, K.,Kim, Y.,Yang, J.,Ha, K.S.,Usta, H.,Lee, J.,Kim, C. Korean Society of Industrial and Engineering Chemi 2017 Journal of industrial and engineering chemistry Vol.46 No.-

<P>The effect of alcohol on methane-water volumetric mass transfer coefficient (1(0) and solubility of methane was investigated in this study. Various alcohols including methanol, ethanol, 1-propanol, butanol, and pentanol were added to aqueous solution and enhancement of both methane-water k(L)a (from 72h(-1) to 471 h(-1)) and solubility (from 21.72 mg/L to 30.41 mg/L) was observed, depending on alcohol type and concentration. Among all alcohols, 1-propanol exhibited largest enhancement via bubble coalescence inhibition effect. Enhanced methane-water kLa and methane solubility in aqueous solution were employed for the fermentation of Methylosinus trichosporium OB3b, and cell growth rate and maximum optical density were increased by 700% and 730%, respectively, by addition of 1-propanol. (C) 2016 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.</P>

Enhanced mass transfer rate and solubility of methane via addition of alcohols for Methylosinus trichosporium OB3b fermentation

김광민,김유진,양정모,하경수,Hakan Usta,이진원,김충익 한국공업화학회 2017 Journal of Industrial and Engineering Chemistry Vol.46 No.-

The effect of alcohol on methane–water volumetric mass transfer coefficient (kLa) and solubility ofmethane was investigated in this study. Various alcohols including methanol, ethanol, 1-propanol,butanol, and pentanol were added to aqueous solution and enhancement of both methane–water kLa(from 72 h 1 to 471 h 1) and solubility (from 21.72 mg/L to 30.41 mg/L) was observed, depending onalcohol type and concentration. Among all alcohols, 1-propanol exhibited largest enhancement viabubble coalescence inhibition effect. Enhanced methane–water kLa and methane solubility in aqueoussolution were employed for the fermentation of Methylosinus trichosporium OB3b, and cell growth rateand maximum optical density were increased by 700% and 730%, respectively, by addition of 1-propanol.

Light-induced Repulsive Thermocapillary Effects를 이용한 액적의 이동궤적 제어

원준(June Won),이우영(Wooyoung Lee),강승민(Seungmin Kang),송시몬(Simon Song) 한국가시화정보학회 2015 한국가시화정보학회 학술발표대회 논문집 Vol.2015 No.12

증발 액적 내부 유동의 스케일링 관계 및 액적 표면 점착 조건의 영향

이희웅(Hee Woong Lee),강관형(Kwan Hyoung Kang),이정묵(Choung Mook Lee),이상준(Sang Joon Lee) 대한기계학회 2005 대한기계학회 춘추학술대회 Vol.2005 No.11

We analyzed the Rayleigh-type natural convection inside an axisymmetric, two-element evaporating droplet numerically, and the numerical results are verified by experimental results obtained by PIV technique. We found experimentally that the boundary condition on the droplet surface is close to the no-slip condition, which is assumed to be due to the Marangoni effect. The effect of boundary condition on the flow and concentration distribution is discussed based on the numerical results. From the numerical results verified by the experimental results, it is found that the governing scaling factor for the flow field inside a naturally evaporating droplet is the Rayleigh number. It is also shown, as predicted before, that there exists a pseudosteady condition for the velocity field.

The effects of radiation on heat and mass transfer of magnetohydrodynamic Marangoni flow in the boundary layer over a disk

Yanhai Lin,Meng Yang 한국화학공학회 2020 Korean Journal of Chemical Engineering Vol.37 No.1

This study investigated the problem of radiation effects on the flow heat and mass transfer of magnetohydrodynamic steady laminar Marangoni convection in the boundary layer over a disk in the presence of a linear heat source and first-order chemical reactions. The governing partial differential equations of the disk model were established and transformed to a series of ordinary differential equations via suitable self-similar transformations, which were solved numerically by the shooting technique coupled with Runge-Kutta scheme and Newton’s method. The Marangoni number related to temperature and concentration was derived, the effects of the magnetic Hartmann number, Marangoni number, radiation number, heat source number and chemical reaction number related to velocity, temperature, and concentration profiles were analyzed. The results demonstrate that the Hartmann number and Marangoni number have significant impacts on the heat and mass transfer of the Marangoni boundary layer flow. The temperature tends to increase with heat generation and decrease with heat absorption, and it exhibits a delay phenomenon for significant heat generation cases. Negative/positive chemical reactions tended to increase/decrease the concentration, similar to the effect of heat generation/absorption on the temperature.