선박용 소형 수직축 풍력발전기 활용

허영근,백석흠,최경호 한국유체기계학회 2015 한국유체기계학회 학술대회 논문집 Vol.2015 No.12

생체 내, 외에서 양막 위에 배양한 토끼 상피세포의 형태와 부착복합체 형성에 대한 연구

허영근,최시환,고선미,이양원,차무병 대한안과학회 2006 대한안과학회지 Vol.47 No.1

Purpose: The morphologic characteristics and adhesion complex formation of cultured limbal epithelium of rabbit on amniotic membrane, in vitro and in vivo. Methods: Rabbit limbal explants were cultured in vitro on amniotic membrane for 4 weeks. In the in vivo culture, the rabbit corneal epithelium was removed. Next, a tunnel was created at the limbus and, the edge of amniotic membrane was secured in the tunnel and cultured for 4 weeks. The proliferation of epithelium on the amniotic membrane was observed for 4 weeks at 1 week intervals. Results: AE-5 immunohistochemical staining was positive and PAS staining was negative for cultured rabbit limbal epithelium, in vitro and in vivo. Hematoxylin & Eosin staining showed the morphologic characteristics of normal rabbit corneal epithelium in both groups. Transmission electron microscopy performed at an interval of 1 week showed adhesion complex by 3 weeks of in vitro culture, and no significant change was seen until week 4. The formation of the adhesion complex was shown starting at week 1 of in vivo culture and increased until week 4. Conclusions: The morphology of corneal limbal epithelium of rabbits cultured on amniotic membrane in vitro and in vivo, did not differ significantly compared with normal rabbit epithelium. In vivo culture resulted in more a normal-looking adhesion complex compared with the in vitro culture.

미소 액적 내부 유동의 속도측정에 관한 연구 - 굴절영상의 이미지 보정

허영근,전영훈,서용권 한국가시화정보학회 2009 한국가시화정보학회지 Vol.7 No.2

In this paper we report the method of visualizing and measuring the fluid flow within a small droplet of millimeter size. We use a vertical laser sheet in visualization of the micrometer size and special attention is given to the arrangement of microscope to obtain clear images. Then we use a PIV technique to measure the velocity of the internal flow from the images taken. Since the droplet is of spherical shape, the images represent highly deteriorated picture of the real objects due to the refraction phenomenon. In order to compensate the refraction, we in this study developed two kinds of methods for the real velocity. In the first method, the refracted images are directly used to obtain the velocity in the image space, and then the velocity is transformed to the real space. In the second method the images are first transformed to the real-space objects, and then the PIV is used to measure the velocity field. We compared the two results to prove the usefulness of the compensation technique. In this paper we report the method of visualizing and measuring the fluid flow within a small droplet of millimeter size. We use a vertical laser sheet in visualization of the micrometer size and special attention is given to the arrangement of microscope to obtain clear images. Then we use a PIV technique to measure the velocity of the internal flow from the images taken. Since the droplet is of spherical shape, the images represent highly deteriorated picture of the real objects due to the refraction phenomenon. In order to compensate the refraction, we in this study developed two kinds of methods for the real velocity. In the first method, the refracted images are directly used to obtain the velocity in the image space, and then the velocity is transformed to the real space. In the second method the images are first transformed to the real-space objects, and then the PIV is used to measure the velocity field. We compared the two results to prove the usefulness of the compensation technique.

小型高速 Diesel機關의 燃燒室特性과 傾向에 對한 考察

許永根 東亞大學校 1966 東亞論叢 Vol.3 No.-

Successful combustion inside the cylinders of a diesel engine depends on the prevalence of the following four conditions: 1. Fine atomization 2. High temperature for prompt ignition 3. High relative velocity between fuel and air particles 4. Good mixing of fuel and air particles Atomization, penetration, and "dispersion" (spreading) of the fuel depend largely on the injection system. Compression ratio, cylinder dimensions, and cooling arrangements determine the temperature conditions Mixing depends on the proper relation of the injection pattern, the air, intake system, and the shape of the combustion space formed by the cylinder bead, the cylinder walls, and the piston crouen. The important factors in bringing the temperature up to the level needed for prompt ignition are compression ratio and engine size. In a smallbore engine, the surface of the combustion space is large, relative to its volume, and the coolwater-jackets lower considerably the temperature of the compressed charge. To offset this, smallbore engines generally use higher compression ratios to produce higher temperatures. Another important reason for higher compression ratios in small-bore engines is the fact that such engines run at high speeds. This reduces the time available for combustion and requires reducing the ignition delay: higher compression shortens the delay period. The remaining essential factor in combustion is air motion, which is necessary for good mixing most combustion spaces, even the simplest, produce some stirring of the air, or "turbulence," and this is sufficient for engines with fairly large cylinder bores and operating at low or medium speeds. On the other hand, small-bore, high speed engines require highly developed combustion chambers to prepare the fuel charge and produce the conditions needed for complete combustion in the fantastically short time available. We'll look into some various of combustion chambers. The combustion chambers generally used in compression-ignition engines may be classified under three heads, the directed sprected spray type, the air-swirl type, and the pre-combustion chamber type. The distinguishing characteristic of directed-spray type is that mixing of the fuel and air is accomplished chiefly by directing the spray so that fuel will be projected to all parts of the combustion chamber during the injection process. This usually requires subdivision of the spray and use of high injection pressures. The system is the most common and successful for relatively low-speed engines (large cylinder sizes) and with considerable excess air. The effectiveness of the mixing process is not generally sufficient to permit operation of high-speed engines of this type with small amounts of excess air. The air-swirl system, which rapid motion of air passes the jet, is used to secure good mixing. A single jet is usually sufficient and spray characteristics are less important than in the directed-spray type, Good performance with a small amount of excess air at relatively high r.p.m. is possible with this type. Excellent performance has been obtained with this type. The pre-combustion chamber type utilizes the early stages of combustion to secure rapid mixing. Fuel is injected into a bottle-necked chamber which comprises only part of the combustion space. The first part of combustion occurs in this space and the resultant expansion projects a large portion of the contents of the pre-combustion chamber out through the "bottle-neck"so violently that the effective mixing of the air and unburned fuel is secured Spray characteristics are even less important than in the air-swirl type. By proper detail design and proper proportioning of the volume of the pre combustion chamber relative to the whole combustion space the rate of combustion in the second and third stages is subject to some control. With combustion chambers having compartments separated from the cylinder by small passages both heat loss and pumping friction are likly to relatively high. The heat lost during compression may cause difficulty in starting a cold engine. High compression ratios and "glow plugs" are usually necessary for starting. Many of the combustion chambers have stainless steel liners which have poor thermal contact with the water-cooled parts, and therefore run at high temperatures, projection of the fuel spray against these hot surfaces helps to keep the delay period short. The question of variation of optimum injection timing with speed for the various types of combustion chamber is of considerable practical interest. In the directed spray and pro-chamber types the process of mixing fuel and air is a function of time rather than of engine speed, and hence ocuepies more degrees of crank rotation as r.p.m. are increased. Thus the injection timing must be "advanced" with these types as speed increases. In those types dependent for mixing on air flow(swirl) past the jet, the velocity of air flow increases with engine speed, and optimum injection timing tends to vary less with changes of speed. In many engines of the later type a fixed injection timing is satisfactory over a considerable speed range.

자료 : 1985년도 정기 총회 및 학술발표회 - C-4. 국내 토양중 항균성 방사선상균의 분퐁 대한 연구 (1)

허영근,김성원 한국균학회 1985 韓國菌學會誌 Vol.13 No.4

數學的 思考 技法의 訓練를 通한 問題 解決力 伸張 方案

林龍潭,金昞淵,金相植,奇應舒,許永根 光州大學校 初等敎育硏究所 1988 初等敎育硏究 Vol.3 No.1

算數科 問題解決力 伸張을 위한 授業改善方案

許永根,奇應舒,金昞淵,林龍潭,金相植 光州大學校 初等敎育硏究所 1989 初等敎育硏究 Vol.4 No.1

바람의 유입각도에 따른 건물 설치형 수평축 풍력발전기 성능에 대한 CFD 연구

허영근(Young Gun Heo),최낙준(Nak Joon Choi),최경호(Kyung Ho Choi),김경천(Kyung Chun Kim) 대한기계학회 2014 대한기계학회 춘추학술대회 Vol.2014 No.5-2

패브릭 블레이드를 적용한 100W급 수직축 풍력발전기 개발

허영근(Young-Gun Heo),정원혁(Won-Hyuk Jung),정종현(Jong-Hyun Jeong) 한국산학기술학회 2023 한국산학기술학회논문지 Vol.24 No.10

본 논문은 패브릭을 이용한 100 W급 사보니우스형 수직축 소형 풍력발전기의 개발에 대한 내용이다. 패브릭 소재를 적용하여 블레이드 파손에 의한 사고를 예방하고 저속회전이 가능한 사보니우스형태를 적용하여 로터 회전에 의한 위협감을 줄이고자 하였다. 기본 설계를 통하여 로터의 형상 치수를 결정하고 유동해석을 통하여 정격 조건에서의 정격 출력을 확인하였다. 그리고 구조적 안전성을 고려하기 위하여 정격 출력 조건과 극한 조건에 대한 구조해석을 수행하였으며 정격 풍속 조건에서의 안전율은 30.4 이상, 극한 풍속 조건에서의 안전율은 10.5로 구조적 안전성을 확인하였다. 유동해석 결과, 106.8 W의 출력을 확인하였으며 이를 토대로 풍력발전기 로터를 제작하였다. 풍동시험을 통하여 로터의 출력을 검증하였으며 개선된 로터의 풍동 시험 결과는 107.9 W가 나타남을 확인하였다. This paper presents the development of a 100 W Savonius small VAWT (Vertical Axis Wind Turbine) using fabric blades. The aims were to prevent accidents caused by blade damage using fabric material and enable low-speed rotation by adopting the Savonius-type rotor, reducing the hazards associated with rotor rotation. The dimensions of the rotor were determined through the basic design. Computational Fluid Dynamics (CFD) confirmed the rated power output under rated operating conditions. In addition, structural analysis was performed for both rated wind speed conditions and extreme wind speed conditions to assess the structural safety. The safety factors were 30.4 or higher at rated wind speed conditions and 10.5 at extreme wind speed conditions, confirming the structural integrity. The CFD results confirmed the power output of 106.8 W. The wind turbine rotor was manufactured based on the CFD results. Wind tunnel testing was conducted to validate the rotor performance, and the wind tunnel test results from the improved rotor achieved 107.9 W.

問題解決學習

許永根,林龍潭,金昞淵,奇應舒 光州大學校 初等敎育硏究所 1987 初等敎育硏究 Vol.2 No.1