Comparison of experimental and predicted atomization characteristics of high-pressure diesel spray under various fuel and ambient temperature

박수한,김형준,이창식 대한기계학회 2010 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.24 No.7

The aim of this study is to investigate the effects of the fuel temperature and the ambient gas temperature on the overall spray characteristics. Also, based on the experimental results, a numerical study is performed at more detailed and critical conditions in a high pressure diesel spray using a computational fluid dynamics (CFD) code (AVL, FIRE ver. 2008). Spray tip penetration and spray cone angle are experimentally measured from spray images obtained using a spray visualization system composed of a high speed camera and fuel supply system. To calculate and predict the high pressure diesel spray behavior and atomization characteristics, a hybrid breakup model combining KH (Kelvin-Helmholtz) and RT (Rayleigh-Taylor) breakup theories is used. It was found that an increase in fuel temperature induces a decrease in spray tip penetration due to a reduction in the spray momentum. The increase of the ambient gas temperature causes the increase of the spray tip penetration, and the reduction of the spray cone angle. In calculation, when the ambient gas temperature increases above the boiling point, the overall SMD shows the increasing trend. Above the boiling temperature, the diesel droplets rapidly evaporate immediately after the injection from calculation results. From results and discussions, the KH-RT hybrid breakup model well describes the effects of the fuel temperature and ambient gas temperature on the overall spray characteristics, although there is a partial difference between the experimental and the calculation results of the spray tip penetration by the secondary breakup model.

용융알루미늄의 물성에 미치는 oxide particles의 영향 (초)

박수한,강광중,탁병수,김병구,허보영 대한금속재료학회 ( 구 대한금속학회 ) 2008 대한금속재료학회 학술대회 개요집 Vol.2008 No.1

호텔기업의 지적자본인 인적자본, 구조적자본, 고객자본이 비재무적 성과에 미치는 영향

박수한,안호준,이동수,김홍범 한국외식산업학회 2023 한국외식산업학회지 Vol.19 No.6

With the management environment of business turning into a knowledge-intensive environment, the evaluation categories of intangible assets, such as, the knowledge of employees, customers and supplies, innovation of management environment, and so forth have become more important over the evaluation of corporate competitiveness through tangible assets. Such an intellectual capital is deemed to be the basis of success and influence on value creation and management performance of companies that it is important to engage in systematic and efficient intellectual capital in a way of contributing to the management performance. Accordingly, the purpose of this study is to contemplate human capital, structural capital and customer capital that comprise the intellectual capital of hotel enterprises and study on influence of intellectual capital on the non-financial performance as its major performance. This study is aimed at formulating the key factors that perceived by the employees regarding the intellectual capital of hotel enterprises and measuring the noticeable influence on non-financial performance. Based on the document studies, the empirical study has been administered with the targets in employees who are engaged in intellectual capital related affairs in hotel enterprises. The intellectual capital of hotel enterprises are presented in structural capital, customer capital and human capital, and it is demonstrated that the intellectual capital of hotel enterprises has made positive (+) influence on non-financial performance

Direct Open Venous Drainage: An Alternative Choice for Flap Congestion Salvage

박수한,최우영,손경민,천지선,양정열 대한두개안면성형외과학회 2015 Archives of Craniofacial Surgery Vol.16 No.3

In this report, we present a scalp defect reconstruction with lateral arm free flap. We highlight the difficulty in obtaining a recipient vein and the venous drainage managed through an open end of the donor vein. A 52-year-old woman presented with a pressure sore on the left scalp. A lateral arm free flap was transferred to cover this 8×6 cm defect. The arterial anastomosis was successful, but no recipient vein could be identified within the wound bed. Instead, we used a donor venous end for the direct open venous drainage. In order to keep this exposed venous end patent, we applied heparin-soaked gauze dressing to the wound. Also, the vein end was mechanically dilated and irrigated with heparin solution at two hour intervals. Along with fluid management and blood transfusion, this management was continued for the five days after the operation. The flap survived well without any complication. Through this case, we were able to demonstrate that venous congestion can be avoided by drainage of the venous blood through an open vessel without the use of leeches.

‘公武체제’의 論理와 座次儀禮

박수철(朴秀哲) 동양사학회 2016 東洋史學硏究 Vol.137 No.-

발포재료(Al)의 점성 및 표면장력과 첨가요소의 영향에 관한 연구

박수한,김상열,안득규,하동인,조순형,배석천,허보영,Park, Soo-Han,Kim, Sang-Youl,Ahn, Duck-Kyu,Ha, Dong-In,Cho, Soon-Hyung,Bae, Suk-Cheon,Hur, Bo-Young 한국재료학회 2002 한국재료학회지 Vol.12 No.9

Porous Al metal was produced by batch type casting process. In this foaming process, the viscosity and surface tension of molten Al as two most important factors have been investigated in the temperature range of 680-95$0^{\circ}C$ by the ring method and rotational method respectively. The experimental results showed that both the surface tension and viscosity of the melt decreased linearly with increasing temperature. Addition of Ca decreased surface tension, but increased viscosity significantly.

용탕의 물성 변화에 따른 Near-net shape Foam의 제조 특성 (초)

박수한,송영환,성환구,서창환,허보영 대한금속재료학회 ( 구 대한금속학회 ) 2007 대한금속재료학회 학술대회 개요집 Vol.2007 No.1

Transient Exotropia after Open Reduction of a Naso-Ethmoidal-Orbital Fracture

박수한,최우영,손경민,천지선,양정열 대한성형외과학회 2016 Archives of Plastic Surgery Vol.43 No.1

EFFECTS OF INJECTION STRATEGY ON THE NANO-PARTICLE EMISSION CHARACTERISTICS OF A DIRECT INJECTION DIESEL ENGINE

박수한,이승현 한국자동차공학회 2022 International journal of automotive technology Vol.23 No.2

In this study, the influence of variation of engine speed, injection mass, injection timing, and split injection strategy on the combustion, exhaust emissions and nanoparticle emission characteristics in a small direct injection (DI) diesel engine were experimentally investigated. The experimental results show that with the increase of engine speed, the peak combustion pressure and peak ROHR profile were increased and ignition delays were shortened. The NOx emission was considerably increased. The combustion characteristics of the three different injection mass cases indicated similar trends and patterns of combustion pressure and rate of heat release at a given test condition. As the injection fuel mass increased, the concentrations of soot emission generally showed increasing patterns with advanced injection timing. The strategy of a first injection mass of 7 mg and a second injection mass of 3 mg (7+3 mg) resulted in the maximum combustion pressure compared to the other cases. As the first injection mass was increased, the mode diameter of particles increased, and with the increase of the first injection mass, a significant shift to larger particle diameters was observed. However, with the reduced first injection mass, the number per volume of ultrafine particles ranges, was significantly increased.

NCS기반 절삭가공 실무과목 수업에 대한 특성화고 기계계열 교사의 인식

박수한,김진수 대한공업교육학회 2020 대한공업교육학회지 Vol.45 No.1

The Ministry of Education has been quick to apply National Competency Standars (NCS) to industrial sites and educational · training institutions in order to resolve discrepancies between practical affairs in industrial sites and vocational education, training & requirements. Full implementation of NCS-based curriculum in vocational education of vocational high schools has been mandatory since 2018. This research used a region-stratified sample of 350 from teachers in ‘machinery’ and ‘machine․metal’ majors in mechanical departments of vocational high schools to investigate the awareness of practical courses for metal machining among the teachers. The research results are as follows. First, a majority of the respondents indicated the availability of turning process, milling process, computer integrated manufacturing and measuring courses in mechanical departments. Second, capabilities required by the industry are considered most in selecting practical courses and competence units. Third, positive changes with the introduction of practical courses in the school education are students' practical skills improvement and satisfaction of industrial requirements. Fourth, negative changes with the introduction of practical courses in the school education are too difficult learning modules used in practical courses for students and students’ difficulty in learning because of the difference between equipment in schools and industrial equipment in learning modules. Fifth, teachers’ satisfaction with practical courses classes and overall conditions is above the average, and their satisfaction with the level of practical courses and bookbinding or purchase of rearranged textbooks of practical courses is below the average. Therefore, application conditions of above-mentioned representative 4 practical courses should be examined and taken care of for consistent improvement to stabilize NCS-based educational courses in mechanical departments. 교육부에서는 산업현장의 실무와 직업교육 및 훈련, 자격 내용의 불일치 해소를 위해 국가직무능력표준(NCS)을 활용하여 산업현장과 교육․훈련기관 등으로 빠르게 적용해 나가고 있으며, 2018년도부터 특성화고등학교의 직업교육에 NCS기반 교육과정을 전면 도입하도록 의무화하고 있다. 이 연구는 특성화고의 기계계열인 ‘기계’ 및 ‘기계․금속’전공 교사를 대상으로 350명을 지역별로 유층 표집하여 절삭가공 실무과목 적용에 대한 교사의 인식을 조사하였다. 연구 결과는 다음과 같다. 첫째, 기계관련 학 과에서 선반가공, 밀링가공, 컴퓨터활용생산, 측정과목의 적용률은 전체 응답자 중 대부분을 차지하고 있으며 둘째, 실무과목 및 능력단위 선정 시 고려사항에 대한 교사 인식은 산업체 요구능력이 가장 높다. 셋째, 실무과목 도입으로 인한 학교 교육에서의 긍정적인 변화에 대한 교사 인식은 학생의 실무 능력 향상과 산업체 요구 충족이 가장 높으며 넷째, 실무과목 도입으로 인한 학교 교육에서의 부정적인 변화에 대한 교사 인식은 실무과목 수업에 활용되는 학습모듈의 수준이 학생의 수준에 비해 너무 어렵다는 것과 학습모듈에 집필되어 있는 산업체 장비와 학교 장비가 차이가 있어 수업에 대한 어려움을 느끼고 있다. 다섯째, 실무과목 수업 및 제반 여건에 대한 교사 만족도는 보통 이상이며 실무과목의 수준, 재구성된 실무과목 교재를 제본 또는 구매하는 것에 대한 만족도는 보통 이하이다. 따라서 기계관련 학과의 NCS기반 교육과정의 안정적인 정착을 위해서는 가장 대표성을 띠는 위 4개 실무과목의 활용 실태를 점검하고 지속적으로 개선하는 데 노력해야 한다.