초음파에 의한 액체 미립화 특성에 관한 연구

주은선(Eun Sun Ju),송민근(M.G.Song),최우창(W.C.CHoi),박영호(Y.H.Park) 한국자동차공학회 1998 한국자동차공학회 춘 추계 학술대회 논문집 Vol.1998 No.11_1

The application of the ultrasonic atomization has been extended because of its good merits. Influx, liquid load, and physical properties are the effecting factors to the size of spray droplets. In this study, distilled water and city water are selected as reference liquids and gasoline, kerosene, and petroleum as fuel liquids. Characteristics and affinity to get the maximum effect for the ultrasonic atomization are observed by using the two ultrasonic transducers with 28KHz and 2MHz.<br/> Results show that the size distributions of liquid spray droplet by direct vibration method prevail over the aerosol method in uniform droplet size and as a whole, liquid droplet sizes and spray quantum are decreasing according to the head increasing.<br/>

수소 연료 생산의 효율향상을 위한 초음파 응용에 관한 연구 - 압력센서 계기에 의한 -

송민근,손승우,주은선,Song, Min-Guen,Son, Seung-Woo,Ju, Eun-Sun 대한기계학회 2003 大韓機械學會論文集B Vol.27 No.9

The production of hydrogen fuel depends basically on the water electrolysis. The ultrasonic effects the decrease of the overpotential in a water electrolysis. A study on the overpotential which activates the hydrogen production is the core to elevate the hydrogen production efficiency on the principle. A pressure sensor system by a new idea is developed and applied. Solutions are 4 kinds of KOH concentration such as 0%, 10%, 20%, and 30%. Two frequency bands of the ultrasonic transducer are 28kHz and 2MHz. The directions of ultrasonic forcing are the vertical direction and the horizontal direction. The temperatures are two states, i.e., no constant and constant. Experiments are carried out sequentially in order in three cases of no ultrasonic forcing, ultrasonic forcing, and ultrasonic discontinution. In results, it is clarified that the ultrasonic effects the decrease of overpotential to elevate the efficiency of hydrogen production.

Rod 형상 변화에 따른 유동 특성연구

손승우(Son Seung-Woo),이상범(Lee Sang-Bum),송민근(Song Min-Geun),주은선(Ju Eun-Sun) 대한기계학회 2002 대한기계학회 춘추학술대회 Vol.2002 No.5

The objective of this study is to investigate characteristics of flow by the rod shape and the choice of the turbulent intensity enhancement section. The rod was set up vertically to the way of a nozzle exit flow and the nozzle diameter is 17mm. The rod height is 5mm and the shapes of rod are square, triangle, and circle. Characteristics of fluid such as velocity vector distribution, kinetic energy, turbulent intensity, and etc. were visualized, observed, and considered at 3 kinds of Re No. such as Re=2000, 3000, 4000. Temperature of water is 20℃ and the measurement region is divided by 3 section( Ⅰ,Ⅱ,Ⅲ). The nozzle diameter is 17mm.<br/> As the experimental result by PlV measurement, the scale of the vector profile showed a tendency to an unbalance parabola distribution as increasing of the Re No. The impinging plates are set up as each shape of spuare, triangle, and circle in front of the flow accelerated. The rod shape in the case of the highest velocity vector is a circle shape and the rod shape in the case of the highest turbulent intensity is a square shape.

수소연료 생산의 효율향상을 위한 초음파응용에 관한 연구-용액과 농도 중심으로 -

송민근(Min Geun Song),이상범(Sang Bum Lee),손승우(Seung Woo Son),주은선(Eun Sun Ju) 한국수소및신에너지학회 2001 한국수소 및 신에너지학회논문집 Vol.12 No.2

An investigation on the A/V(ampere/volt) gradient according to the concentration and the kind of solution in a electrolyzer is carried out to obtain the basic data on the ultrasonic application for the efficiency elevation of the hydrogen fuel production. KOH is selected as an electrolyte and concentrations are 0%, 10%, 20% and 30%. The solutions are city water, city water with nitrogen, distilled water and distilled water with nitrogen. The Electrochemical analyzer(BAS Co.) is used as a measuring device to observe the A/V gradient. And the limit of volt is from -3000mV to +3000mV. The 28kHz magnetic transducer is selected to give them ultrasonic forcing. In results, it is clarified that ultrasonic influences the A/V gradient in the electrolytic solution.

바이오 디젤유로서 미강유의 분무개선에 관한 연구

주은선,정석용 慶尙大學校生産技術硏究所 1994 生産技術硏究所論文集 Vol.10 No.-

This paper is focused on the propriety examination and application plan as a substiution fuel in the rece-bran oil which is obtained as by-product when the rice is milled. Compared with the light-oil, the rice-bran oil has high viscosity, and causes erosion of nozzle, clogging phenomenon. So, in order to solve these problems, the ultrasonic oscillator device has been used and the design of horn was performed, on the basis of physical experimental data of the rice-bran oil. The purpose of the paper is to construct the optimal fuel-injection system using rice-bran oil, therefore it has been performed the experiment to improve the characteristics of an atomization by adding ultrasonic energy on spraying fuel. The sauter mean diameter(SMD) and distribution of spary was measured by using the magnesium oxide method and the immersion one.

LDV에서 散亂子數에 따른 信號特性에 關한 硏究

朱恩選 慶尙大學校生産技術硏究所 1987 生産技術硏究所論文集 Vol.3 No.-

The phenomena of the signal resultant combination are investigated and the parameter for the change of the signal characteristics is found passing scatterers through the probe volume in random state. And results are examined with theoretical equations induced. It is clarified that the resultant visibility can be estimated when the interval between two scatterers is less than the half of the transversal interval of particles and the phase-difference between two particles to the fringe is the parameter of the change for the resultant visibility. In the case of a small number of moving particles (N<10), the visibility is influenced much by the difference of the phase of particles for one side fringe and its change in the increase and decrease is shown remarkably. In the case of N>20 , the curved line of decrease for the visibility on the graph is smooth because the effects of the phase difference of particles is decreased very much by more uniform distribution of particles for fringe.

側壁間에서 靜止로부터 等加速度로 움직이는 物體주위의 非定常流動 : (1) 平板인 경우 (1) In the case of a Flat plate

朱恩選 慶尙大學校 1982 論文集 Vol.21 No.1

Experiments for the wall effects on the flow past a body (in the case of a flat plate) with uniform acceleration are presented. Flow patterns are investigated for dimensionless acceleration ranging from 1.225×10² to 2.9693×10⁴ and ratio of ?? (where d is the width or the diameter of the model, h the channel width) ranging from 0.1 to 0.67. Flow patterns of a flat plate with unifrom acceleration are compared to those with impulsive start. The variation of the length of the vortices with time is determined from the photograph by using a flow visualization technique. It is found that 1) Twin-vortices behind a model with constant acceleration are formed slower than those with impulsive start. 2) Wall-vortices appear when ?? is larger than 0.5 for a flat plate(0.4 in the case of impulsive start). 3) Wall-vortices brings a reducing phenomenon on twin-vortices in the growth.

고속 4-밸브 가솔린 기관의 압력파 동조를 이용한 엔진성능 향상에 관한 연구

정석용,주은선 慶尙大學校生産技術硏究所 1992 生産技術硏究所論文集 Vol.8 No.-

An experimental study on the effects of intake an exhaust pipes on the pressure wave tuning as well as the volumetric efficiency was presented in this paper. Various performance parameters including pressure waves and engine torques were measured for several lengths of intake and exhaust pipes in a four-cycle four-cylinder gasoline engine. The measured date were compared and discussed in order to show detailed effects of intake and exhaust pipes on the volumetric efficiency of the engine.

굴절률이 Dual-Beam LDV의 信號特性에 미치는 影響

朱恩選,羅又禎 慶尙大學校 1986 論文集 Vol.25 No.2

The effects of refractive indices on the visibility which is an important characteristic in a Dual-Beam LDV are investigated. There are two methods for experiment; One is in the case of the variety of refractive indices of scatterers, and the other in the case of the variety of refractive indices of media. In this study, the above second method was selected in order to find that the refractive index is an important parameter on the visibility. A resistance wire with 30㎛ width and a Pt wire with 50㎛ width were applied as scatterers. Five media, ie., H2O(n=1.332), Chloroform (n=1.444), DMSO (n=1.476), Benzyl alcohol (n=1.538) and Carbondisulfide (n=1.628), were used as surrounding media. In the result, it is found that the refractive index of scatter is a parameter of the visibility.

Dual Beam LDV의 數密度에 관한 硏究

朱恩選 慶尙大學校 1985 論文集 Vol.24 No.2

A study on the number density in a dual beam LDV is carried out with irregular arrangements of particles. The thirteen models formed by 1~35 particles are passed into the probe volume in four cases of D/δ: i.e., Dlδ=0.3, 0.5, 1. 0, 1. 5. In the case of a small number of moving particles(N < 10), the visibility is influenced much by the difference of the phase of particles for one side fringe and its change in the increase and decrease is shown remarkably. In the case of a large number of particles, the curved line of decrease for the visibility on the graph is smooth because the effect of the phase difference of particles is decreased very much by more uniform distribution of particles for fringe. And the formula of the number density on the basis of probability - is compared with experimental values.