• Proceedings of the KSME Conference
• /
• 2004.04a
• /
• pp.2005-2010
• /
• 2004

Ultrasonic cleaning is performed by cavitation which is caused by the change of the sound pressure due to the vibration in a cleaning tank. In this study, experiments on electric power and sound pressure with various temperatures, dissolved oxygen and the level of the fluid was done in order to find out how the changes in a cleaning tank affect cavitation. As a result of a series of experiments, we found that transducer impedance changes periodically in response to the variances of fluid and have a direct influence on cleaning efficiency.

• Fire Science and Engineering
• /
• v.27 no.5
• /
• pp.32-37
• /
• 2013

This paper suggested to revise unreasonable national fire safety codes of sprinkler system. Also proposed to modify the definition of "the gridded sprinkler system" and to add "the feed main" in terms of the definition of the pipes. In order to operate the regulations of discharge pressure of the sprinkler head efficiently, this paper checked the minimum criteria of pressure and flow for the pipe schedule sprinkler system of NFPA 13 and suggested to establish the similar minimum demand criteria. It proposed to be amended properly the pressure calculation formular in the pressure tank system and to use the correct K value due to change in pressure unit and to use the [bar] as a unit of pressure for the sake of using the existing K-factor etc.

• Proceedings of the Korean Society of Marine Engineers Conference
• /
• 2006.06a
• /
• pp.65-66
• /
• 2006

As industrial technology recently, a field of marine engineering is demanding integration and manless system. In this study, tank monitoring system is developed, which is able to watch real-time the marine tank for measuring a level, pressure, temperature. The system will provide efficiently measuring data for operator.

• Korean Chemical Engineering Research
• /
• v.52 no.5
• /
• pp.574-580
• /
• 2014

Storage tanks of Carbon dioxide ($CO_2$) carriers utilized for the purpose of carbon capture and storage (CCS) into subsea strata have to undergo a pre-cooling session before beginning to load cryogenic liquid cargos in order to prevent physical and thermal deterioration of tanks which may result from cryogenic $CO_2$ contacting tank walls directly. In this study we propose dynamic model to calculate the tank inflow of $CO_2$ gas injected for precooling process and its dynamic simulation results under proportional-integral control algorithm. We selected two cases in which each of them had one controlled variable (CV) as either the tank pressure or the tank temperature and discussed the results of that decision-making on the pre-cooling process. As a result we demonstrated that the controlling instability arising from nonlinearity and singularity of the mathematical model could be avoided by choosing tank pressure as CV instead of tank temperature.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2006.11a
• /
• pp.54-58
• /
• 2006

There are many kinds of propellant tank for space systems, which should be designed and manufactured considering lots of conditions such as pressure of inside and outside, temperature and weight, etc. Among them, it is the one of the most important factors that the tanks could be designed to suspend and support the applied static and dynamic loads. Tank mounting, that installs and supports a tank in the structure, is a method that should be considered the rigid and tight jointing mechanism, including the manufacturing simplicity, the light weight and the economical budget. Methods and features for several propellant tank mountings are introduced in this paper with the applications for those in some foreign space program.

• Proceedings of the Korean Society For Composite Materials Conference
• /
• 2005.04a
• /
• pp.17-20
• /
• 2005

In-situ structural health monitoring of filament wound pressure tanks were conducted during water-pressurizing test using embedded fiber Bragg grating (FBG) sensors. We need to monitor inner strains during working in order to verify the health condition of pressure tanks more accurately because finite element analyses on filament wound pressure tanks usually show large differences between inner and outer strains. Fiber optic sensors, especially FBG sensors can be easily embedded into the composite structures contrary to conventional electric strain gages (ESGs). In addition, many FBG sensors can be multiplexed in single optical fiber using wavelength division multiplexing (WDM) techniques. We fabricated a standard testing and evaluation bottle (STEB) with embedded FBG sensors and performed a water-pressurizing test. In order to increase the survivability of embedded FBG sensors, we suggested a revised fabrication process for embedding FBG sensors into a filament wound pressure tank, which includes a new protecting technique of sensor heads, the grating parts. From the experimental results, it was demonstrated that FBG sensors can be successfully adapted to filament wound pressure tanks for their structural health monitoring by embedding.

• Geomechanics and Engineering
• /
• v.17 no.5
• /
• pp.413-420
• /
• 2019

The changes in earth pressure and ground settlement due to underground excavation near an existing retaining wall were studied experimentally according to the separation distance between the underground excavation and the retaining wall. In addition, this study attempted to experimentally prove that the arching phenomenon occurred during the construction of the underground space. A model tank having 120 cm in length, 160 cm in height, and 40 cm in width was manufactured to simulate underground excavation through the use of five separated base wall bodies. The variation of earth pressure on the retaining wall was measured according to the underground excavation phase through the use of 10 separated right wall bodies. The results showed that the earth pressure on the retaining wall was changed by the lowering of the first base bottom wall; however, the earth pressure was not changed significantly by the lowering of the third base bottom wall, since the third base wall had sufficient separation distance from the retaining wall. Lowering of the first base wall induced a decrease in the earth pressure in the lower part of the retaining wall; in contrast, lowering of the first base wall induced an increase in the earth pressure in the middle part of the retaining wall, proving the arching effect experimentally. It is necessary to consider the changes in earth pressure on the retaining wall in designing earth retaining structures for sections where the arching effect occurs.

• The KSFM Journal of Fluid Machinery
• /
• v.4 no.3 s.12
• /
• pp.53-61
• /
• 2001

Vortex type Fluidic Device(FD) which is installed at the bottom of Safety Injection Tank(SIT) controls the discharge flow rate from the tank. In case of loss of coolant accident the injection water flows into primary system in two steps; initial high flow rate for certain period of time and subsequent low flow rate. By two-step control of the discharge flow rate, FD can ensure the effective use of water in the tank. A small-scale FD has been tested to obtain a required flow characteristics maintaining full pressure and height of prototype, which are the major contributing parameters. Through the testing of many different arrangements of internal geometry of FD, most appropriate one was selected and its performance data was obtained. As characteristics of FD, time dependent Euler number, flow rate and pressure are presented and discussed. Also a method to predict the full size FD is presented.

• Special Issue of the Society of Naval Architects of Korea
• /
• 2005.06a
• /
• pp.38-43
• /
• 2005

The present study is concerned with the numerical analysis of the sloshing impact pressure of the Liquefied Natural Gas (LNG) carriers in rough sea. The reliable predictions of the both random tank motions in irregular waves and violent fluid flow in the LNG tanks are required for practical sloshing analysis procedure of LNG carriers. The three-dimensional numerical model adopting SOLA-VOF scheme is used to predict violent free surface movements of LNG tank in irregular motions. For accurate input motion of tank, a three-dimensional panel method program called SSMP (Samsung Ship Motion Program) is applied for seakeeping analysis. Comparison studies of sloshing analysis are carried out for No.2 tank of 138K and 205K LNG carriers to verify the safety of the LNG containment system of the proposed 205K large LNG carrier.

• Journal of Hydrogen and New Energy
• /
• v.31 no.6
• /
• pp.558-563
• /
• 2020

Hydrogen is attracting attention as an alternative energy source as an eco-friendly fuel without emitting environmental pollutants. In order to use hydrogen as an energy source, technologies such as hydrogen production and storage must be used, and new storage methods are being studied. In this study, the behavior of hydrogen in the storage tank were numerically studied under high-pressure hydrogen discharge conditions in a Type III hydrogen tank. Numerical results were compared with the experimental value and the results were quantitatively analyzed to verify the numerical implementation. With the results of pressure and temperature values under a given discharge condition, the Redich-Kwong gas model showed the adequate models with the smallest error between numerical and experimental results.