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해상에서의 시추작업은 해저면을 통해서 시추되는 유정에서 이루어지는 일련의 기계적 프로세스라 할 수 있다. 해양 시추설비는 해저에 매장된 석유나 가스의 매장량 확인을 위한 테스트 유정(well)과 이를 경제성 있는 생산용 유정으로 만들기 위해 사용되는 시설로 해양에서의 시추작업은 대부분 타 지역으로의 이동을 위해 이동식으로 제작되며, 작업 해역의 수심에 따라 크게 리그(jack-up, semi-submersible)와 드릴십(drillship)으로 구분할 수 있다. 최근에는 석유와 가스의 개발을 위한 시추작업이 급진적으로 심해로 옮겨가고 있으며 작업 가능 수심이 3,000 m에 이르고 있다. 본 논문에서는 이러한 해상 시추설비에 탑재되는 대표적 해양플랜트 기자재인 시추시스템을 소개하고 최근의 기술개발 동향을 알아보고자 한다. Offshore drilling refers to a mechanical process where a wellbore is drilled through a seabed. It is typically carried out in order to explore for and subsequently extract petroleum which lies in rock formations beneath the seabed. There are many different type of facilities from which offshore drilling operations take place. These include bottom founded drilling rigs, combined drilling and production facilities either bottom founded or floating platforms, and deepwater mobile offshore drilling units including semi-submersibles and drillships. These are capable of operating in water depths up to 3,000 m. In this paper, we introduce the drilling system, which is mounted on the offshore drilling facilities.
Hardware in the loop (HIL) simulation has become increasingly popular in recent years, because of its ability to shorten product development time for complex dynamic systems through quick and cost efficient testing over a wide range of conditions. HILS is a technique where machine control software runs virtual machines, which are mathematical models emulating the physical machines. This paper introduces the research on development of control system for offshore drilling equipment and HIL as a methodology for drilling control system software testing.
The purpose of this study is to investigate planning of urban energy supply systems configuration and operating conditions for the district heating and cooling system using combined heat and power system. Generally the district heating and cooling system has been known to one of the effective way for energy saving, cost reduction and demand side management of energy. Economical analyses were carried out and operating characteristics for some systems were examined in terms of GER factor which represents to the ratio of gas and electricity costs. Rates of the energy consumption and the CO₂ emission were compared from the system configuration of the energy supply system with new district cooling system with the conventional one.
The building HVAC systems have very different qualities of performance and durability with the superintendent's ability for management and maintenance. The poor management of these systems finally result in the increase of operating costs and energy consumptions due to low efficiency. This paper presents an overview of monitoring and analyzing in-situ performance of absorption type chiller which has a capacity of 250 RT. The operating data were used in the evaluation of system's performance and LCC based economic analysis for the decision of efficient management and maintenance plan. The results led to finding a possible energy saving method and efficient maintenance and management method of the building HVAC systems.
Demands for the high efficient and high performance energy supply system having been continuously increased according to the rise of quality of life and rapid increases of energy cost all over the world. District cooling system with combined heat and power plant offers massive and collective cooling energy production, which is higher in efficiency than conventional systems. But the district cooling system in Korea mainly consists of absorption type chiller, located in the demand sides and district hot water is supplied to the absorption type chiller. This study proposes new district cooling system configuration for district cooling with combined heat and power plant in order to maximize its benefits to a new urban development. The calculated results show that the new district cooling system is able to reduce operating costs and to get higher energy efficiency compared with conventional system.
The goal of building energy management is to minimize the energy consumption while maintaining the comfortable environment. Building energy management, especially which target is HVAC energy saving, is the most critical issue for existing building operation and service. That is why HVAC energy consumption occupies the biggest portion about 47% in total energy consumption of commercial building. In this study we examined running data of HVAC systems to know about problems of management of the office building and suggested improvement plan. The results led to finding a possible energy saving method and efficient maintenance and management method of the office building HVAC systems.
The present study concerns a computational study of fully developed laminar flow of a Newtonian fluid through an eccentric annulus with a combined bulk axial flow and inner cylinder rotation. This study considers the identical flow geometry as in the calculation of Escudier et al. An unexpected feature of the calculations for eccentricity ε=0.7 is the appearance of a second peak in the axial velocity, located in the narrowing gap. The distribution of the axial component of the surface shear stress has a maximum in the narrowing gap and a minimum in the widening gap.
An experimental investigation is conducted to study a 2-phase vertically upward hydraulic transport of solid particles by water and non-Newtonian fluids in a slim hole concentric annuli with rotation of the inner cylinder. Rheology of particulate suspensions in viscoelastic fluids is of importance in many applications such as particle removal from surfaces, transport of proppants in fractured reservoir and cleaning of drilling holes, etc. In this study a clear acrylic pipe was used in order to observe the movement of solid particles. Annular velocities varied from 0.3 m/s to 2.0 m/s. The mud systems which were utilized included fresh water and CMC solutions. Main parameters considered in the study were inner-pipe rotary speed, fluid flow regime and particle injection rate. Pressure drops and average flow rates were measured in the Reynolds number range of 10²<Re<10⁴. For both water and 0.2% CMC solutions, the higher the concentration of the solid particles is, the larger the pressure gradients become.