• Fire Science and Engineering
• /
• v.29 no.6
• /
• pp.109-118
• /
• 2015

Recently, three kinds of search robot prototypes were developed to assume the role of fire fighters for search and rescue missions in special disaster areas with high heat, smoke, toxic gases, or radioactivity. To accomplish search missions, these robots should be able to endure heat, overcome various obstacles, suppress fires, and see through dense smoke. This study investigated the heat resistance, practicality, and fire fighting capacity of these robots. The results show that the small and middle-sized robots were resistant to surrounding temperatures of $100{\sim}200^{\circ}C$, and the fire-fighter-riding robot could endure up to $500^{\circ}C$ for half an hour. The fire-fighter-riding robot showed excellent extinguishing performance on an A-10 class fire model, which was extinguished within 3 min. The robots also showed various capacities for overcoming obstacles and are expected to play an active role in various special disaster areas.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.23 no.7
• /
• pp.941-947
• /
• 2017

Increasing marine transportation of dangerous goods using containers causes fire accidents on ships due to leakage of dangerous materials. In IMO (MSC.93), all vessels that are to be loaded five or more containers on weather deck area after 1 January 2016 are required to have a fire extinguishing system called Water Mist Lance (WML) on board. In this study, numerical analysis is performed to design WML with optimal edge radius of curvature using LS-DYNA. The analysis results for the three models with 10 mm, 15 mm and 20 mm lengths of the edge part showed that the only model with 15 mm length penetrated the wall of the container and did not cause damage to the edge of the WML. In the future, based on the results of this study, we will make a WML of prototype and conduct a performance test. And we will continue to improve the problems.

• Journal of the Korean Society of Industry Convergence
• /
• v.25 no.1
• /
• pp.61-70
• /
• 2022

Fire damage time in high-rise buildings and wildland fire increasing every year. The use of high-pressure fire pumps is required to effectively extinguish fires. Reflecting the curvature effect of the fire hose occurring at the actual fire fighting site, this study provides a database of pressure drop, discharge velocity and maximum discharge height through C FD numerical analysis and it can provide using standards for fire extinguishing. Two Reynolds numbers of 200000 and 400000 were numerically analyzed at 0° -180° bending with water of 25℃ as a working fluid in hoses with a diameter of 65mm, a length of 15m, and a radius of curvature of 130mm. Realizable k-ε turbulence model was used and standard wall function was used. The pressure drop increases as the bending angle increases, and the maximum value at 90° and then decreases. The increasing rate is greater than the decrease. The velocity of the secondary flow also decreases after having the maximum value at 90°. The decreasing rate is greater than the increase. The turbulent kinetic energy increases to 120° and decreases with the maximum value. Pressure drop, velocity of the secondary flow, and turbulence kinetic energy are measured larger in the second bending region than in the first bending region.

• Fire Science and Engineering
• /
• v.24 no.4
• /
• pp.62-68
• /
• 2010

The present study purposed to develop the water mist package system for the cultural properties fire prevention and fire suppression system through analyzing fire protection system and cultural property's characteristic, and to suggest directions for the development of cultural property fire prevention system in the future. Maximum safety with minimum damage has issued a main objective in fire protection of the cultural property in Korea. Two types of the water mist nozzles having a low pressure had been developed by KEI. The one is for inside using in wooden cultural properties, the flow rate is 30~35 l/min and the discharging pressure is 13~14 bar. The other one is for out-side of wooden properties, the flow rate is 25~30 l/min and the discharging pressure is 14~15 bar. To evaluate the nozzles performance test, we made the fire scenario and full-scale model of wooden cultural properties for fire test. The size of full-scale model was 4.9 m length, 4 m wide, 6.6 m height, all was made by wooden. This real fire test results showed that the low pressure water mist nozzles having a $200{\mu}m$ dour size were very effectively fire extinguishing and suppression on wooden cultural properties fire. Even though the oil fuel fire was not extinguished, the fire suppression effects for the during mobilization of fire brigade was enough.

• Fire Science and Engineering
• /
• v.26 no.4
• /
• pp.55-62
• /
• 2012

The suppression mechanisms of carbon dioxide ($CO_2$) as a representative fire suppression agent were revisited using a counterflow diffusion flame which could be applied the concept of a local application system. To end this, the low strain rate $CH_4$/air counterflow diffusions with $CO_2$ addition in either fuel or oxidizer stream were examined numerically using detailed-kinetic chemistry. Radiative heat loss due to radiating gas species including $CO_2$ added was considered by the optically thin model (OTM). As a result, the critical $CO_2$ volume fractions in the oxidizer stream required to extinguish the flame were in good agreement with the experimental data reported in the literature, while somewhat under-prediction was observed with $CO_2$ added in the fuel stream. The surrogate agents were adopted to estimate the quantitative contribution with changing in global strain rate ($a_g$) on the flame extinguishment among pure dilution effect, thermal effects including radiation heat loss and chemical effect due to the $CO_2$ fire suppression agent.

• Journal of Electrical Engineering and Technology
• /
• v.13 no.6
• /
• pp.2545-2552
• /
• 2018

$SF_6$ has been widely used in high voltage power equipment, such as gas insulated switchgear (GIS) and gas insulated transmission line (GIL), because of its excellent insulation and arc extinguishing performance. However, $SF_6$ faces two environmental problems: greenhouse effect and high liquefaction temperature. Therefore, to find the $SF_6$ substitute gases has become a research hotspot in recent years. In this paper, the liquefaction characteristics of $SF_6$ substitute gases were studied. Peng-Robinson equation of state with the van der Waals mixing rule (PR-vdW model) was used to calculate the dew point temperature of the binary gas mixtures, with $SF_6$, $C_3F_8$, $c-C_4F_8$, $CF_3I$ or $C_4F_7N$ as the insulating gas and $N_2$ or $CO_2$ as the buffer gas. The sequence of the dew point temperatures of the binary gas mixtures under the same pressure and composition ratio was obtained. $SF_6/N_2$ < $SF_6/CO_2$ < $C_3F_8/N_2$ < $C_3F_8/CO_2$ < $CF_3I/N_2$ < $CF_3I/CO_2$ < $c-C_4F_8/N_2$ < $C_4F_7N/N_2$ < $c-C_4F_8/CO_2$ < $C_4F_7N/CO_2$. $SF_6/N_2$ gas mixture showed the best temperature adaptability and $C_4F_7N/CO_2$ gas mixture showed the worst temperature adaptability. Furthermore, the dew point temperatures of the $SF_6$ substitute gases at different pressures and the upper limits of the insulating gas mole fraction at $-30^{\circ}C$, $-20^{\circ}C$ and $-10^{\circ}C$ were obtained. The results would supply sufficient data support for GIS/GIL operators and researchers.

• Fire Science and Engineering
• /
• v.29 no.2
• /
• pp.84-91
• /
• 2015

The purpose of this study is to suggest the reasonable model of the caliber in suction nozzle, the pressure of suction nozzle, and the flow rate about foam system of line proportioner type using in the pumpcar. To test this, the experimental study was accomplished on the ground of the standards for the Performance Certification and Product Inspection of Foam Fire-extinguishing Chemical Mixing Machine. Aqueous Film Forming Foam in 3% and pipe type air foam nozzle with line proportioner FE 40 type were used. Test result showed that the pressure of suction nozzle within the limits between 0.25 MPa and 0.35 MPa was appropriate when the caliber in suction nozzle is 4 mm. Also, the pressure of suction nozzle within the limits between 0.45 MPa and 0.60 MPa was appropriate in the higher pressure than 4 mm when the caliber in suction nozzle is 5 mm.