다공성 매질을 통한 극저온 액체의 유동과 열적 특성에 대한 연구

학위논문 (박사)-- 서울대학교 대학원 : 기계항공공학부, 2013. 2. 이우일.The importance of fluid flow and heat transfer with a change in phase arises from the fact that many industrial processes rely on these phenomena for material processes and energy transfer. Examining fluid flow related to heat transfer with a change in phase involves multiphase flow analysis, which can be adapted to various applications. In particular, flow phenomena of a cryogenic liquid subjected to evaporation are of interest to understanding cryogenic liquid behavior in a porous structure. One of the purposes of this study is to evaluate the flow and heat transfer of cryogenic liquid in porous media. An experimental investigation on the behavior of cryogenic liquid in porous media, glass wool, with various densities showed how the cryogenic liquid behaves in a porous structure. This study examined the thermophysical properties of glass wool with different bulk densities in terms of the temperature dependence and permeability behavior under different applied pressures. The experimentally determined thermal properties were used to examine the characteristics of the two main experimental results. Two distinct experiments showed the nonlinearity of the pressure distribution over distance increased as the bulk density of the glass wool increased, and the increase rate of pressure gradient became greater with the applied injection pressure. Simulation results were used to understand a cryogenic liquids flow in porous media, and were compared with experimental results. Numerical simulation showed good agreement with experiment results. The numerical approach presented in the paper would enable a more efficient analysis and better understanding of cryogenic liquids behavior in the porous structure. Another purpose of this study is to develop and present numerical and experimental model for LNG leakage phenomenon in the porous structure to predict more reasonable thermal effect of LNG CCS hull structure when LNG is leaked through the porous media for damages and failures. Given that LNG cargo containment systems (CCS) operate in a range of environmental temperatures that includes cryogenic temperatures, thermal analysis should be carried out to determine thermal safety of the hull plate. Two phase mixture model which was verified with experiment of flow for the cryogenic liquid was adopted for LNG leakage phenomenon. The numerical parametric studies, flow and transient heat transfer analysis were presented with the scenario that LNG leaked into the insulation panel with different inlet pressure and defect size. In this scenario, thermal safety was evaluated with the criterion that the bottom hull plate part has the critical criterion that hull plate mild steel is vulnerable to the below a ductile-to-brittle transition temperature of -60 °C. With 2 mm diameter defect area, thermal safety can be maintained, however, over 5 mm diameter defect area, temperature of hull plate drops below -60 °C. Thermal penetration depth depends on the inlet pressure of LNG, though, the maximum penetration depth didnt exceed 30 % of hull thickness.Abstract Contents List of Figures List of Tables Nomenclature CHAPTER 1. INTRODUCTION 1.1 Overview and problem description 1.2 Literature review 1.3 Research Objective and scope CHAPTER 2. BACKGROUND AND THEORY 2.1 Overview of LNG carrier 2.2 The configuration of two types of LNG cargo containment system 2.3 Porous media flow 2.3.1 Flow through porous media, Permeability 2.4 Thermal properties for the transport of energy through materials 2.4.1 Thermal conductivity of gases and liquids 2.4.2 Thermal conductivity of solids CHAPTER 3. EXPERIMENTS 3.1 Introduction 3.2 Experimental materials 3.2.1 Liquefied nitrogen 3.2.2 Glass wool 3.2.3 Plywood 3.2.4 Polyurethane foam 3.3 Material properties of Glass wool 3.3.1 Morphological parameter of glass woolporosity with different bulk density 3.3.2 Thermophysical material properties of glass wool: specific heat and thermal conductivity 3.4 Experimental equipment and procedure 3.4.1 Permeability measurement 3.4.2 Thermal conductivity measurement for LNG CCS insulation materials 3.4.2.1 Guarded hot plate method 3.4.3 Measurement of cryogenic liquid flow in porous media 3.5 Experimental result and discussion 3.5.1 Permeability measurement 3.5.2 Thermal conductivity measurement for LNG CCS insulation materials 3.5.3 Flow of cryogenic liquid in glass wool 3.5.3.1 Flow in square-section cylinder 3.5.3.2 Flow in rectangular duct CHAPTER 4. NUMERICAL ANALYSIS 4.1. Modeling method for evaporation of liquefied nitrogen (LNG) 4.2. Numerical modeling and methods 4.2.1 Mass conservation equation for the mixture 4.2.2 Momentum conservation equation for the mixture 4.2.3 Energy equation for the mixture 4.2.4 Relative (Slip) velocity and the drift Velocity 4.2.5 Calculation model and conditions used in the analysis 4.3 Simulation results 4.3.1 Flow in Square-section cylinder 4.3.2 Flow in rectangular duct CHAPTER 5. NUMERICAL PARAMETRIC STUDY 5.1 Overview of CFD analysis 5.2 Considerations and boundary conditions for the LNG leakage simulation 5.2.1 Geometric dimensions of the insulation panel (Mark Ⅲ system) for the LNG leakage problems. 5.2.2 Analysis conditions for the LNG leakage problems 5.3 Results of parametric study for the LNG leakage problem 5.3.1 In case of 2mm diameter defect area. 5.3.2 In case of 5mm diameter defect area. 5.3.3 In case of 8mm diameter defect area. 5.4 Conclusion of parametric study of LNG leakage. CHAPTER 6. SUMMARY AND CONCLUSIONS References Figures Tables Abstract (In Korean)Docto

Composition of Project-Based Organization of Musical Industry in Seoul

지식기반 경제에서 산업의 성장과 발전을 주도하는 핵심적인 요소는 행위 주체 간 학습과 지식창출이다. 지금까지 문화산업에 대한 다양한 연구들이 있었지만 문화산업에 있어서의 지식창출과 그 행위에 주체에 대한 연구는 상대적으로 큰 주목을 받지 못했다. 본 연구에서는 다양한 문화산업 중 서울시 뮤지컬 산업을 대상으로, 주요 생산주체라 할 수 있는 뮤지컬 제작사에 관한 연구를 수행하였으며, 서울시 뮤지컬 제작사의 조직 특성과 제작 조직 구성의 기준 및 역할 구분을 프로젝트 기반 조직의 관점에서 살펴보는 것을 목적으로 하였다. 연구 결과, 서울시 뮤지컬 제작사는 대체적으로 제자고가 기획, 홍보 · 마케팅 관련 인력만을 갖추고 있고, 작품을 제작할 때만 일시적으로 제작 조직을 구성하는 프로젝트 기반 조직의 형태를 보이고 있다. 작품 제작을 위해 프로젝트 기반 조직을 구성할 때는 작품의 콘셉트와 해당 인력에 관한 뮤지컬 업계 내 평판을 조직 구성의 중요한 정보로 활용하며, 공동 작업을 수행하면서 상호 신뢰가 형성되면 다음 작품 할 때도 우선적인 섭외대상이 된다. 구성원의 교체는 작품 콘셉트가 바뀌었거나 작품이 좋은 평가를 받지 못했을 경우 혹은 작품을 통해 새로움을 추구하고자 할 때 발생하게 된다. 프로젝트 기반 조직 내 업무는 제작 · 기획 업무와 홍보 · 마케팅 업무가 혼재되어 있는 것으로 나타났으며, 전체적으로 예술 부문은 연출가, 이외 제작 업무와 조직의 전체적인 조정은 제작자가 중심으로 되어 이루어진다. 또한 국내 뮤지컬 업계에는 연출가 출신 제작자가 상당수 존재하고 있어 예술부문에 대한 과도한 간섭이 이루어지는 경우도 있다. The critical factors that lead industrial growth and development in knowledge-based economy are learning among principal agents and knowledge creation. Even though there have been various studies on cultural industry, the study on knowledge creation and its main agent in cultural industry has not received enough attention. Among different kinds of cultural industry, this study focuses on musical industry in Seoul and musical production company, which is the main production agent. The purposes of this study are to examine organizational characteristics of musical production company, criteria of composition of production organization and task classification from a perspective of project-based organizations. As a result, most musical production companies in Seoul are project-based organizations, which originally consist of staffs in planning, public relation, and marketing department but organize a temporary production team in case they plan to give a performance. When these organizational units work for production, they utilize concept of certain musical and musical actors' reputation as crucial information. As the companies develop mutual trust with their counterparts prep따.ing a performance, they tend to work with those p따.tners by priority. Bad evaluation on a performance or change in its concept or pursuit of novelty usually result in replacement of existing casts or staffs. The tasks of production . planning and public relation . marketing department are mingled to some extent. Overall, directors play a pivotal role regarding art, whereas producers lead organizational arrangement and production tasks. In Korean musical industry, since there exist a number of producers who worked as director, their excessive interference with art sector is also observed

Composition of project-based organizations and the knowledge creation of musical industry in Seoul

학위논문 (석사)-- 서울대학교 대학원 : 지리학과, 2011.2. 박삼옥.Maste