• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.24 no.4
• /
• pp.429-438
• /
• 2011

In this paper, experiment of thermal conductivity among thermal properties for CCS insulation material was carried out under the condition ranged from room temperature to cryogenic temperature. CCS insulation system should be sustained under cryogenic temperature($-163^{\circ}C$), and lots of investigations will be conducted how to block the heat to insulation material. CCS components which consist of various materials are especially the main interests, and how the temperature of the entire CCS along the location is should be investigated through these studies. With the experimental thermal properties, the steady state thermal analysis of the entire cargo system was conducted. When the LNG leaked through the insulation system with external impact, temperature distribution and thermal safety of secondary barrier, especially plywood and hull structure, was observed.

• Journal of the Korea Convergence Society
• /
• v.13 no.4
• /
• pp.53-61
• /
• 2022

Accidents are steadily occurring due to machine defects and carelessness during LNG storage operations. In previous studies, an environmental sensor module capable of measuring pressure, temperature, gas concentration, and flow to detect danger in advance was developed and the response speed according to the amount of leaked gas was measured. This paper proposes the development of a wired and wireless communication module that transmits data measured by the environmental sensor module to embedded devices connected to wired and wireless networks of SPI, UART, and LTE. First, a data communication module capable of interworking with an environmental sensor is designed. Design a protocol between devices in the Local Control Part and wired and wireless protocols in the Local Control Part and Remote Control Part. Ethernet, WiFi, and LTE communication modules were designed, and UART and SPI channels that can be linked with embedded controllers were designed. As a result, it was confirmed through a UI (User Interface) that each embedded device transmits data measured by the environmental sensor module while simultaneously communicating on a wired and wireless basis.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.27 no.4
• /
• pp.529-537
• /
• 2021

Membrane-type hull and cargo holds have been designed and built for large ship. However, there is a growing interest in applying the same technology to small and medium-sized Liquefied natural gas(LNG) carriers to meet the recent increase in demand for LNG as an ecofriendly fuel and for expanding LNG bunkering infrastructure. The purpose of this study is to apply the IMO Type-B tank to small and medium-sized LNG carriers and verify the safety and suitability of the design. Fatigue crack propagation analysis was performed to install a partial second drip tray installed at the lower part of the LNG cargo tank by calculating the amount of leaked gas in the support structure supporting the cargo tank. First, a program for fatigue crack propagation analysis was developed, in which Paris' law and British Standard 7910 (BS 79110) were applied based on the International Code for the Construction of Equipment and Ships Carrying Liquefied Gases in Bulk, an international standard for LNG carriers. In addition, a surface crack propagation analysis was performed. Next, a methodology for assuming the initial through-crack size was developed to determine the size of the partial second barrier. The analysis was performed for 15 days, which is a possible return time after cracks are detected. Finally, the safety and suitability of the IMO Type-B for LNG cargo tanks required by international regulations were verified. For the accurate analysis of fatigue crack propagation, it is necessary to develop and verify the analysis procedure based on direct analysis and international regulations.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.34 no.9
• /
• pp.875-883
• /
• 2010

The thermal performance of LNG fuel tanks of vehicles is determined by the time for non-venting storage of fuel and the amount of fuel supplied to the engine. In this study, we selected a double-walled vacuum-insulated fuel tank with a volume of 450 liter, and the properties of the fuel contained in it were assumed to be the same as those of the methane($CH_4$). For the increasing the non-venting fuel storage time, we propose the use of shielded penetration pipes in the tank. We compared the storage times of the tank used in our study with those of the conventional fuel tank. Further, the additional heat input required to maintain the fuel pressure necessary for an appropriate fuel supply rate was predicted. For these parameters, we derived a thermodynamic relationship that can be used to estimate the rate of increase in pressure for a known heat input, and we obtained equations for estimating the rate of heat leaked by using the established heat transfer model. From the results of numerical computation, we found the non-venting storage time of the tank with shielded pipes to be 25-30% higher than that of the tank with unshielded pipes. Further, we determined the appropriate operation conditions by taking into consideration the transfer rate of additional heat provided to the fuel tank.