입자부상제트에서 입자로딩비와 분사속도가 입자 및 이송가스에 미치는 영향에 대한 연구

윤정수,윤영빈 한국항공우주학회 2014 한국항공우주학회 학술발표회 논문집 Vol.2014 No.4

본 논문은 입자부상제트에서 입자의로딩비 및 분사속도가 유동특성에 미치는 영향 및 입자 자체의 분포특성에 대하여 연구하였다. 입자와 이송가스의 특성을 동시에 계측하기 위하여 이송가스의 특성을 파악하기 위한 1μm 의 입자와 42μm 의 큰 입자를 동시에 분사하여 이를 PIV 기법을 통하여 측정하였다. 이렇게 PIV 기법을 통하여 측정된 이미지로부터 산란광의 세기와 입자의 크기를 이용하여 1 μm 와 42μm 의 입자를 분리하였다. 분리된 이미지를 통하여 각 상의 유동특성과 분포를 측정하였다. 이를 통하여 입자의 로딩비가 증가 할수록 이송가스의 축방향 속도감소율이 감소한다는 것을 알 수 있었고, 입자의 수밀도 분포는 입자 로딩비가 증가 할수록 반경방향으로 넓게 분포하고 분사속도가 증가 할수록 젯 중심부근에 집중적으로 분포함을 알 수 있었다. This paper investigated the effect of particle loading ratio and nozzle exit velocity on the fluid phase and particle dispersion characteristics in particle-laden jet. Particle Image Velocimetry was used by simultaneously injection 1μm and 42μm particles for the represent fluid and solid phase to obtain simultaneously particle and fluid velocity, From the scattering image obtained by the PIV method, the object are sorted into solid and tracers according to parametric combination of size and brightness. Solid and fluid velocity and dispersion characteristics was measured from sorted image. Fluid phase centerline velocity decay rate decreases according to particle loading ratio increases, then particle widely distributed with increase of particle loading ratio and particle intensively located in the centerline of the jet with increase of nozzle exit velocity.

입자영상유속계를 이용한 비강 유동의 측정

김진국,김성균,남태욱,임채형,손영락,한창준 대한이비인후과학회 2002 대한이비인후과학회지 두경부외과학 Vol.45 No.11

Background and Objectives:Several studies have utilized physical models or casts of the nasal cavity in an efort to understand the relationship betwen nasal anatomy and the distribution of inspired or expired airflow. This paper deals with the evaluation of nasal airflow characteristics during physiologic breathing in normal conditions. Materials and Method:The choana of a nasal model casting by a combination of rapid prototyping and solidification of clear silicone was connected to a pump that marked with polyvinyl spherical particles, and was observed through an solidificated clear silicone and analyzed with particle image velocimetry. Results:Turbulence is clearly visible at the level of the head of the midle turbinate. The maximal velocity was recorded at the superior meatus. The flow rate was highest at the midle meatus. Conclusion:This model allows the in-vestigation of airflow distribution and velocity under physiologic conditions. The main flow stream pases through the middle meatus. (Korean J Otolaryngol 2002 ;45 :1063-8)

입자부상 동축 분사기에서 입자로딩비가 유동 특성과 입자분포에 미치는 영향에 대한 연구

윤정수(Jungsoo Yoon),윤영빈(Youngbin Yoon) 한국추진공학회 2015 한국추진공학회지 Vol.19 No.3

Experimental research on characteristics of particle-laden jet by using a coaxial injector was conducted in order to design fuel and oxidizer injectors of the supercavitation underwater vehicle. 1 μm and 42 μm particles was simultaneously injected to obtain particle and fluid velocity. Small particles(1 μm) and large particles represent fluid and fuel characteristics respectively. Small particles, which was processed using PIV algorithms, and one for the large particles processed using PTV algorithms. Fluid phase axial velocity increases according to particle loading ratio increases, and particles are located at the outside of the high vorticity region in a mixing layer of a coaxial injector.

PIV를 이용한 이상 유동에서 자성입자 거동 측정

이창제(ChangJe Lee),이상엽(Sangyoup Lee) 대한기계학회 2018 대한기계학회 춘추학술대회 Vol.2018 No.12

Particles which have different material conditions and mechanical properties behave their special motions under the external conditions. Fe3O4 particles which have magnetic properties also have their own characteristics such as align through the solenoid-nozzle in external magnetic field. When the external magnetic field appears, Fe3O4 particles have been changed because of their magnetism compare with other non-magnetic particles like polystyrene particles. To optimize the solenoid-nozzle, change the magnet wire span size and connection method. The result show that span layer 1 and parallel connection generated high amp then span layer 5 and serial connection. We used 1um fluorescent magnetic nano particles and 1um fluorescent polystyrene particles which have different emission wavelength range to separate each image of particles under the one and two phase flow in the solenoid-nozzle. Both particles excited from 532nm laser system and their emission signals were imaged with two color fluorescent Particle Image Velocimetry(PIV). One EM-CCD camera with dichroic filter were used to capture images for separate phases. Instantaneous images for both magnetic and nonmagnetic nano particle was captured simultaneously.

외부 자계 영향을 받는 자성 나노 입자 거동에 대한 2색 형광 PIV 적용

이창제(ChangJe Lee),이상엽(Sangyoup Lee) 대한기계학회 2017 대한기계학회 춘추학술대회 Vol.2017 No.11

Particles which have different material conditions and mechanical properties behave their special motions under the external conditions. Fe3O4 particles which have magnetic properties also have their own characteristics such as align through the solenoid-nozzle in external magnetic field. When the external magnetic field appears. Fe3O4 particles have been changed because of their magnetism compare with other non-magnetic particles like polystyrene particles. To optimize the solenoid-nozzle, change the magnet wire span size and connection method. The result show that span layer 1 and parallel connection generated high amp then span layer 5 and serial connection. We used 200nm fluorescent magnetic nano particles and 500nm fluorescent polystyrene particles which have different emission wavelength range to separate each image of particles under the one and two phase flow in the solenoid-nozzle. Both particles excited from 532nm laser system and their emission signals were imaged with two color fluorescent Particle Image Velocimetry (PIV). One EM-CCD camera with dichroic filter were used to capture images for separate phases. Instantaneous images for both magnetic and nonmagnetic nano particle was captured simultaneously.

입자부상 동축 분사기에서 입자와 유동의 상호작용에 대한 연구

윤정수(Jungsoo Yoon),윤영빈(Youngbin Yoon) 한국추진공학회 2014 한국추진공학회 학술대회논문집 Vol.2014 No.12

초공동 수중운동체의 연료 및 산화제 분사기 설계를 위한 동축형 분사기를 이용한 입자 부상제트의 특성에 대한 실험적 연구가 수행되었다. 특히, 입자부상제트에서 입자 로딩비 및 분사속도가 유동특성에 미치는 영향 및 입자 자체의 분포특성에 대하여 연구하였다. 입자와 이송가스의 특성을 동시에 계측하기 위하여 이송가스의 특성을 파악하기 위한 1 ㎛의 입자와 42 ㎛의 큰 입자를 동시에 분사하여 이를 PIV 기법을 통하여 측정하였다. 이를 통하여 입자의 로딩비가 증가 할수록 이송가스의 축방향 속도 감소율이 감소한다는 것을 알 수 있었고, 입자 분포는 높은 와도를 지니는 혼합영역 바깥 부분에 주로 분포한다는 것을 알 수 있다. Experimental Research on characteristics of particle-laden jet by using a coaxial injector was conducted in order to design fuel and oxidizer injectors of the supercavitation underwater vehicle. Especially this paper investigated the effect of particle loading ratio and nozzle exit velocity on the fluid phase and particle dispersion characteristics in particle-laden jet. Particle Image Velocimetry was used by simultaneously injection 1㎛ and 42㎛ particles for the represent fluid and solid phase to obtain particle and fluid velocity simultaneously. Fluid phase centerline velocity decay rate decreases according to particle loading ratio increases, and particles are located at the outside of the high vorticity region in a mixing layer of a coaxial injector.

Experimental investigation of particle distribution in a flow through a stenosed artery

Anis Shuib,Peter Hoskins,William Easson 대한기계학회 2011 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.25 No.2

The particle distribution of a dilute solid-liquid suspension through a stenosed arterial geometry was investigated. Particle image velocimetry (PIV) was used to determine the velocity as well as to acquire the flow images. The light intensity scattered by particles was evaluated to determine the particle distribution. Flow separation exists where the flow emerges from the stenosis throat. From the PIV images, the particle density distribution exhibited differing non-uniform characteristics which vary with flow rate, particle size and particle concentration. At low flow rates, a particle-free layer is formed. As the flow rate is increased, particles accumulate in concentric recirculation orbits within the downstream vortex. Particles with larger size and higher concentration tend to accumulate more towards the center of the vortex.

An economical method to measure granular flow in a hopper using a commercial digital camcorder and particle image velocimetry

Byoungjun Cha,박준영 한국자원공학회 2016 Geosystem engineering Vol.19 No.3

Numerous methods including X-ray imaging, magnetic resonance imaging, and particle image velocimetry (PIV) have been suggested to measure the flow of particles. However, most methods usually require costly equipment. In this study, we measure the velocities of particles in a hopper using a PIV system with open source software and an inexpensive commercial digital camcorder. The proposed system shows high accuracy. The measurement error is less than .5%, and the error of recording speed (frames per second) is about 2.5%. This error rate is negligible because it is lower than the experimental error. Consequently, our findings demonstrate that a PIV system with sufficient accuracy to measure particle flow in a hopper can be developed with a small budget.

New Algorithm in the Particle Tracking Velocimetry using Self-Organizing Map

Joshi Shashidhar Ram 한국멀티미디어학회 2010 한국멀티미디어학회 국제학술대회 Vol.2010 No.-

The self-organizing maps (SOM) model seems to have turned out particularly effective for the particle tracking algorithm of the PIV system. This is mainly because of the performance of the particle tracking itself, capacity of dealing with unpaired particles between two frames and no necessity for a priori knowledge on the flow field (e.g. maximum flow rate) to be measured. Initially, concept of SOM was applied to PIV by Labonte. It was modified by Ohmi and further modified algorithm is developed using the concept of Delta-Dar-Delta rule. It is a heuristic algorithm for modifying the learning rate as training progresses. Earlier, the treatment of unpaired particles, a specific problem to any type of PIV, is not fully considered and thereby, the tracking goes unsuccessfully for some particles. The present research is to bring about further improvement and practicability in this promising particle tracking algorithm. The computational complexity can be reduced employing modified algorithm compared to other algorithms. The modified algorithm is tested in the light of the synthetic PIV standard image as well as in particle images obtained from visualization experiments.

임의로 움직이는 물체 주위의 PIV 기법 개발

전영진(Young Jin Jeon),성형진(Hyung Jin Sung) 한국가시화정보학회 2009 한국가시화정보학회 학술발표대회 논문집 Vol.2009 No.11

This paper presents a PIV (particle image velocimetry) image-processing method for determining fluid velocities in the vicinity of an arbitrarily moving body. An image processing technique such as a contour-texture analysis based on user-defined textons is used to obtain the locations of arbitrarily moving interface. After tracking the fluid-wall interface, the particle images near the arbitrary interface are delivered to the mapping process which obtains a coordinate transformation between a curvilinear-real image and a rectangularsynthetic image. Accurate measurements near the interface can be achieved by applying a window deformation algorithm in concert with IPX (image parity exchange) and PIV/IG (interface gradiometry) to the particle image which is transformed to the rectangular coordinate. Quantitative evaluations of this method are performed with computer-generated images, and the results suggest that this method measures unknown interface velocities accurately. A steel flag measurement in a water channel is carried out for examination of this method.