가스추진선박의 가스연료공급시스템에 대한 CFD를 이용한 정량적 위험도 해석에 관한 연구

LNG has significant advantages in regard to environmental aspects comparing with conventional oil. In case of using LNG, it is estimated that NOx and SOx emission can be reduced by about 90% and 100%, respectively. Therefore, LNG enables us to comply with stricter emission requirements for ships under the MARPOL Convention combined with regionally enforced Emission Control Areas (ECA) and GHG emission reduction initiated by IMO. LNG-fuelled ship have been considered to be the best option both from an environmental and an economic point of view. Along with these trends, some major shipyards and Classification Societies have started to carry out the risk-based system design for LNG-fuelled ship. However, new conceptual gas fuelled ship has high risk level compared with vessels using traditional oil especially in view of gas explosion accident. Therefore safety area which is installed fuel gas supply system is required risk based system design with special considerations. First of all, in order to control the risk level, hazards should be identified by experts in various fields and risks should be ranked by semi-quantitative way. Nevertheless, in case of ship design requirements are not satisfied with general safety level, to obtain quantitative risk data, reanalysis is required to meet the available safety level. Quantitative risk analysis has various ways, such as investigating the accident case, opinion collection from experts etc. However quantitative risk analysis using computational fluid dynamics(CFD) is widely used for decisions of risk-based design according to the general advantages of the computational fluid dynamics. Since the engine room with fuel gas supply system is highly confined, it can be congested highly enough to be damaged at partial hull structure and risk sensitive auxiliary equipment by explosion overpressure. For this reason, explosion analysis needs to be performed to prepare the data required to assess the structural resistance or to mitigate the explosion overpressure in the developing new code of safety for ships using gases or other Low flashpoint fuels(IGF Code). In order to obtain quantitative risk data by explosion analysis, gas leak analysis and gas cloud analysis under the strict boundary conditions by conventional regulations should be carried out. According to the results of explosion simulations conducted based on the forecast the size and the position of the gas cloud made available through the gas leak analysis and gas cloud analysis, show the explosion overpressure contours and quantitative graphs in the engine room with fuel gas supply system. Quantitative risk analysis can be carried out various ways however especially explosion analysis should be conducted by quantitative calculation of gas cloud and gas release. Also in order to obtain the information of the characteristics of gas leaks, the use of general purpose chemical process simulator is essential. On this paper, the entire process necessary for the quantitative risk analysis was explained to meet the satisfactory safety level of gas fuelled ship. And the results of this study can further be used to carry out structural analysis or assess the impact on the auxiliary equipment for the similar stage of risk level with traditional vessels using general crude oil.1. 서 론 1.1 개요 1.2 연구 배경 1.2.1 가스추진선 기술 현황 1.2.2 가스 누출에 관한 연구 배경 1.2.3 가스 누출로 인한 폭발에 관한 연구 배경 2. 안전성 평가 2.1 안전성 평가 2.2 HAZID 2.2.1 위험도 평가기준 2.2.2 위험도 매트릭스 2.3 가스추진선에 대한 안전성 평가 2.3.1 HAZID Results 2.3.2 HAZID study result for FGS system 3. 공정해석 3.1 누출가스 분석을 위한 공정해석기법의 적용 3.1.1 가스누출량 산출 3.1.1.1 압력용기 벽면의 파공에 의한 가스 누출량 계산 3.1.1.2 압력용기 연결배관에서의 가스 누출량 계산 3.1.1.3 배관 파단에 의한 가스 누출 3.2 공정해석을 통한 가스누출량 계산 3.2.1 연료저장 시스템의 적용 3.2.2 공정해석의 적용 및 가스누출해석 3.2.3 고압 배관에 대한 가스누출 해석 결과 4. CFD 해석 및 결과 4.1 CFD의 적용 및 가스 클라우드 해석 4.1.1 해석 모델의 선정 및 경계조건 설정 4.1.2 CFD 해석 결과 및 고찰 4.2 가스추진시스템에 대한 폭발 해석 4.2.1 개요 4.2.2 폭발 위험도 4.2.3 폭발 해석 4.2.4 안전요건이 반영되지 않은 폭발해석결과 4.2.5 안전요건이 반영된 폭발해석결과 4.2.6 폭발 위험의 완화 5. 결론 감사의 글 참고문헌Docto

풍력과 조류발전용 수평축 터빈 및 횡류 터빈의 형상설계와 성능평가에 관한 연구

The knowledge in the area of fluid dynamics is increasingly being applied to the field of renewable energy to achieve better design of energy extraction devices. Because the expansion of fluid dynamics such a design optimization of the rotor blades is necessary factor to increase the efficiency of the energy extraction devices and to reduce the unit cost of development. More than 65 countries now have goals for their own renewable energy futures, and are enacting a far-reaching array of policies to meet those goals. More than US$100 billion was lately invested in renewable energy production assets, manufacturing, research, and development. Many renewable technologies and industries have been growing at annual rates of 20 to 60 percent, thereby capturing the interest of the largest global companies and national government agencies. Currently the most active, competitive and representative research area of the renewable energy resources is wind power. Grafting of the aerodynamics significant achieve progress has already been and wind energy has been developing rapidly, start from 10kW-class small wind turbines now reached MW-class large-scale wind farms. Republic of Korea, there is no distinct reference for the related design technology of rotor blade of wind turbine. Therefore the optimum design and evaluation of performance is carried out with foreign commercial code softwares. This paper shows in-house code software that evaluates the aerodynamic design of wind turbine rotor blade using blade element-momentum theory (BEMT) and processes that is applied through various aerodynamics theories such as momentum theory, blade element theory, prandtl's tip loss theory and strip theory. This paper presents the results of the numerical analysis such as distribution of aerodynamic properties and performance curves using in-house code POSEIDON. Just the difference between working fluid, air and water, tidal current energy and wind turbine has significant similarities in generate type. Sea water, which is 832 times denser than air, gives a 2.5 m/s ocean current more kinetic energy than 97 m/s windtherefore ocean currents have a very high energy density, therefore requiring a smaller device to harness that energy than to harness wind energy. In addition, despite of various benefits with the generate principles, development of tidal current energy significant progress has been slowly compared to wind power generation. Wherewith, horizontal axis turbine rotor blade developed with aerodynamic is applied for tidal current energy. Recently 3 bladed horizontal axis rotor blade of the highest efficiency was modified for 100kW class HATT which will be installed at real site, mean tidal current 2.3 m/s position nearby Neok-island in the southern part of Korea peninsula. The HATT was adapted for numerical analysis and the compatibility of HATT is verified using a commercial computational fluid dynamics (CFD) code, ANSYS-CFX. This paper presents results of the numerical analysis, such as pressure, streak line, velocity vector and the performance curves with torque data for the inflow of the horizontal axis tidal current turbine (HATT). Also, among various turbine have been developing with wind energy, cross flow turbine was researched that has a few result of performance analysis for tidal current energy. Therefore, Some potential advantages of ducted and diffuser-augmented current turbine was newly explored. This augmentation channel is designed for generating bi-directionally and a conceptual cross-flow turbine is placed in the augmentation channel. The compatibility of this turbine system is verified using a commercial CFD code, ANSYS-CFX. This paper presents the results of the numerical analysis in terms of pressure, streaklines, velocity vectors and performance curves for 100kW-class cross flow energy integrated type bi-directional tidal current turbine (CEBTT) with augmentation channel.Abstract Nomenclature 제 1 장 서 론 ...........................................................................1 1.1 조류발전 현황 ...............................................................1 1.2 연구동향 ......................................................................4 1.3 연구목적 ......................................................................7 제 2 장 수평축 터빈의 공기역학 ...............................................9 2.1 Actuator Disk 이론 .......................................................9 2.1.1 운동량 이론 ............................................................11 2.1.2 동력계수 (CP).........................................................13 2.1.3 최대 동력계수 (The Betz Limits)..............................14 2.2 Rotor Disk 이론 ..........................................................15 2.2.1 각 운동량 이론 .......................................................17 2.2.2 최대 동력 ...............................................................19 2.3 Blade Element 이론 ....................................................21 2.4 BEM (Blade Element-Momentum) 이론.......................24 제 3 장 형상설계 및 성능평가 .................................................28 3.1 5kW급 풍력발전용 수평축터빈 .....................................28 3.1.1 설계풍속의 결정 .....................................................28 3.1.2 기본 형상 설계 .......................................................30 3.1.3 POSEIDON을 이용한 성능평가 ................................36 3.1.4 결과 및 고찰 ...........................................................40 3.2 100kW급 조류발전용 수평축터빈 ..................................41 3.2.1 설계조류유속의 결정 ...............................................41 3.2.2 기본 형상 설계 ........................................................43 3.2.3 CFD를 이용한 성능평가 ...........................................46 3.2.4 결과 및 고찰 ...........................................................55 3.3 100kW급 조류발전용 횡류터빈 .....................................60 3.3.1 설계조류유속의 결정 ...............................................60 3.3.2 횡류터빈의 개념설계 ...............................................64 3.3.3 CFD를 이용한 성능평가 ...........................................67 3.3.4 결과 및 고찰 ...........................................................76 제 4 장 결론 ..........................................................................80 참고문헌 ...............................................................................82 학술활동 ..............................................................................84 감사의

충남지역 재래시장 상인 경제아카데미 (박경모,김기평)

1. 일본의 상점가와 재래시장 상점가: .지하철, 전철등의 역주위에 인위적으로 형성된 개별 점포의 집합 .주로 의류, 잡화등을 취급 .근린형상점가, 지역형상점가, 광역형상점가, 초광역형상점가 재래시장: .물가안정을 위해 일본정부가 개설한 중소상점의 집합 .주로 농산물, 수산물 등을 취급 .공설시장과 사설시장 구분 - 이후 생략[특강1] 일본의 상점가 성공사례 (시장경영지원센터 전문교수 박경모) [특강2] CS특강, 고객감동과 서비스제고 -환경변화,고객관리 (전문교수 김기평