• 한국연소학회:학술대회논문집
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• 2013.06a
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• pp.109-110
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• 2013

This paper describes gas turbine combustion characteristics of synthetic natural gas which contains a small amount hydrogen content. By conducting ambient pressure high temperature combustion test at gas turbine relevant combustor geometry, the combustion characteristics such as combustion instability, NOx and CO emission, temperatures at turbine inlet, nozzle and dump plane, and flame structure from high speed OH chemiluminescence images were investigated when changing hydrogen content from zero to 5%. From the results, qualitative and quantitative relationships are derived between key aspects of combustion performance, notably NOx/CO emission and combustion instability. Natural gas containing hydrogen up to 5% does not show significant difference in view of all combustion characteristics except combustion instability. Only up to 1% hydrogen addition could not change the pressure fluctuation and phase gas between fluctuations of pressure and heat release. From the results, it can be concluded that synthetic national gas which contains 1% of hydrogen can be guaranteed for the stable and reliable operation of natural gas firing gas turbine.

• Transactions on Electrical and Electronic Materials
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• v.3 no.1
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• pp.9-13
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• 2002

In this work, the surface of inorganic fillers were modified with some functional groups such as stearic acid, aliphatic long chain, vinylsilane and aminosilane to control the interaction between inorganic fillers and polymer matrix. Ethylene-vinyl acetate copolymers (EVA) with various amount of vinyl-acetate and copolyether-ester elastomer were used as polymer matrix. The addition of inorganic fillers increases flame retardancy, but results in steep drop of electrical and mechanical properties, which may be caused by the defects in the interface between organic/inorganic hybrid composites. The hybrid composites are found to show better mechanical properties and higher volume resistivities as inorganic fillers are well dispersed and have good adhesion with polymer matrix. Also, the most effective type of functional group coated on fillers depends on the chemical structure of polymer.

• Fire Science and Engineering
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• v.18 no.2
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• pp.67-72
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• 2004

This study describes to assess combustion characteristics of fiber reinforced plastic (FRP) that is used an elements of building or structure in workplace. The combustion characteristics of the fiber reinforced plastic were carried out using by a Cone Calorimeter according to ISO 5660 standard. As the results of this study, the time to ignition and heat release rate of the fiber reinforced plastic was differ with heat flux of irradiance and content of flame retardant agent. The heat release rate of the fiber reinforced plastic was increased with increasing heat flux of irradiance. The flashover propensity of the fiber reinforced plastic using time to ignition and peak heat release rate was examined according to classification method by R.V. Petrella.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2012.05a
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• pp.96-99
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• 2012

The test facility for confirming performance of a propulsion system is essential infra-structure to develop launch vehicle system. Using the PSTC, cold flow and combustion tests are performed to the propulsion system of individual stage in launcher. Moreover the ground test for the total launching process is conducted. In order to construct the PSTC, we not only have surveyed technology of internal and external countries, but also actively use the case in terms of the system. The test facility consists of feeding system, test stand, control and measurement, and flame deflector.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.34 no.4
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• pp.35-42
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• 2018

This study evaluated the fire resisting capacity and post-fire serviceability of the concrete beams retrofitted by near surface mounted method(NSM) using GFRP plates. Main parameters in the test are grout materials and fire exposure. For the test, two types of grout materials between concrete substrate and GFRP plate were used; flame resisting epoxy and filling mortar. Four RC beam specimens were made and two of them were exposed to fire according to real scale fire curve proposed KS F 2257. After the fire exposure test, flexural test were performed to investigate the flexural performance of concrete beams including strength and deformation. From the test results, it was found that the beam retrofitted by NSM-GFRP presented higher flexural strength than that of the beam without retrofit, which indicates NSM-GFRP retrofit technologies is effective to maintain flexural strength even after fire exposure. In addition, the specimens grouted by epoxy showed good performance in strength but bad performance in ductility.

• Structural Engineering and Mechanics
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• v.87 no.6
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• pp.555-574
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• 2023

An efficient optimization algorithm and damage-sensitive objective function are two main components in optimization-based Finite Element Model Updating (FEMU). A suitable combination of these components can considerably affect damage detection accuracy. In this study, a new hybrid damage-sensitive objective function is proposed based on combining two different objection functions to detect the location and extent of damage in structures. The first one is based on Generalized Pseudo Modal Strain Energy (GPMSE), and the second is based on the element's Generalized Flexibility Matrix (GFM). Four well-known population-based metaheuristic algorithms are used to solve the problem and report the optimal solution as damage detection results. These algorithms consist of Cuckoo Search (CS), Teaching-Learning-Based Optimization (TLBO), Moth Flame Optimization (MFO), and Jaya. Three numerical examples and one experimental study are studied to illustrate the capability of the proposed method. The performance of the considered metaheuristics is also compared with each other to choose the most suitable optimizer in structural damage detection. The numerical examinations on truss and frame structures with considering the effects of measurement noise and availability of only the first few vibrating modes reveal the good performance of the proposed technique in identifying damage locations and their severities. Experimental examinations on a six-story shear building structure tested on a shake table also indicate that this method can be considered as a suitable technique for damage assessment of shear building structures.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.8
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• pp.1134-1141
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• 2003

Performance of a gas turbine combustor installed in a test facility has been studied by measuring spatially- and temporally-resolved temperature distributions using multiplex CARS technique. 500 CARS temperatures were determined at each measuring point to obtain a histogram of temperature distribution. Experiments were carried out in the aero-engine combustor sector rig burning standard kerosene fuel. The histograms were obtained around a triple-sector double annular rig running in ground idle conditions, showing features of flow mixing within the rig. The temperature histograms that prove the existence of high temperatures above 1900 K provide us valuable information to improve the design of the combustor structure suppressing NOx generation in turbulent combustion processes. The effects of swirl direction and pre-filmer on gas turbine combustion were investigated. When we installed radial swirls, a large recirculation zone was formed by the fuel module regardless of swirl directions and the pre-filmer installation. It is found that the swirl direction affects the shape of the reverse flow zone, however. Also, an attempt to estimate the flow field and flame structure is made using the histogram of temperature determined with the CARS technique.

• Journal of Navigation and Port Research
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• v.34 no.6
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• pp.423-427
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• 2010

Land fire receives additional extinguishing methods easily by professional extinguisher. But because of isolation and independence from land when sailing on the sea, ships are difficult to get special help from land. Generally, the death ratio by suffocation is higher than the death rate by flame and to reduce suffocation death ratio, fast evacuation is required. This paper aims to improve survival ratio at ship fires by soot density reduction. This study examines soot density and visibility using FDS. And also examines evacuation time by Pathfinder. The FDS(Fire Dynamic Simulator) is a 3 zone model(Field Model) analysis tool and the patherfinder is a useful analysis tool for evacuation. This research examined about evacuation time using the current regulations of the ship's corridor width and exit width first. And then studied evacuation time again when ship's structure was changed according to the method that is proposed in this paper. And finally compared the results each other.

• Journal of the Korea Institute of Building Construction
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• v.16 no.5
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• pp.397-403
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• 2016

As a building energy saving standard strengthened, The number of building installed external thermal insulation composite system(ETICS) using EPS insulation increased. But frequent fire accident in the buildings installed EIFS using EPS led to strengthening of building fire safety regulation. This study is for fire property of EPS ETICS reinforced with noncombustible calcium silicate-based mineral insulation as a fire spread prevention structure(FSPS). Fire test for large scale wall by ISO 13785-2 was applied and results showed EPS EIFS with FSPS got 3~8 times superior fire safety than normal EIFS by visual investigation. Temperature and heat flux measurement results, which data of upside of specimen were lower than downside, also supported fire safety of EIFS with FSPS.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.2
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• pp.378-385
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• 2016

The internal circuit of the bus-bar for an electrical switch board is a prime cause of electric shock and short circuit accidents due to the exposure of live parts. Electrical fires can also be caused by animals and foreign substances in the switchboard that connect the components with a difficult structure resulting in overheating due to an increase in contact resistance. Preventing these types of accidents is a prime concern in the manufacturing process, such as cutting and bending. In this study, the cutting bus bar of a switch board contained improved modules as a flame retardant that isolates a separate blocks to prevent such problems. This was implemented as a scalable and flexible means of reducing electrical switchboard hazards to offer a safe switch board bus-bar structure of a new connecter type