• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.236-239
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• 2017

A part of the development of Scramjet Engine, this study was performed about Injectors. Barbotage injectors were used for experiment. To study characteristics of injector spray, water is supplied as a main fuel and Nitrogen is supplied for water atomization. Spray test facility and PDPA equipment were used in KARI(Korea Aerospace Research Institute). It was found that gas pressure change and spray distance is important value to spray atomization.

• Fire Science and Engineering
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• v.29 no.5
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• pp.29-33
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• 2015

In this study, the relations of flow rate, discharging distance and droplet size are measured in accordance with the nozzle shape. The dual type nozzles of LPN142 and LPN148, which have identical core diameter (6.0 mm) and the different radial injection angles (${\theta}_2=142^{\circ}$ and $148^{\circ}$), are manufactured. The distribution diameters with discharging distance are quantified by UL2167 test standard. The relations between discharging angle and droplet sizes, which are measured by the method of Helium-Neon laser equipment, are obtained by the empirical correlation as working pressure increase. Moreover, the extinction coefficient, which is major parameter of the radiative transport equation (RTE) is analyzed with variable droplet sizes. Thus, it is possible to opt the nozzle's shape by analyzing the relations of working pressure, spray distance, droplet size and fire characteristics at minimum allowable flow rate.

• Fire Science and Engineering
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• v.25 no.3
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• pp.51-56
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• 2011

The full-scale experiments are carried out to investigate the fire suppression characteristics of water-based fire fighting systems in a road tunnel. Applied systems are the low-pressure water spray system at 3.5 bar and the high-pressure water mist system at 60 bar. The water flow rate of the high-pressure system is one sixth only of the water spray system. A passenger car and a heptane fuel pan with area of $1.4m^2$ are used as fire sources. A blower system is installed at the tunnel exit to realize the longitudinal ventilation conditions (0.9~3.8 m/s) in the tunnel. Temperatures from the fire source to the down-stream direction are measured by K-type thermocouple trees. The experimental results show that the cooling effect of the high pressure water mist system in the test conditions were equivalent to that of the low pressure water spray system for B-class fire.

• Journal of the Korean Society of Propulsion Engineers
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• v.25 no.4
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• pp.59-70
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• 2021

An experimental study was conducted to observe the spray characteristics for different flow rates and rotating speeds of a rotating fuel nozzle of a slinger combustor. The water spray ejected from the nozzle orifice was visualized using a high-speed camera and a light source. It was confirmed that the atomization was improved, as the flow rate decreased and rotating speed increased. The characteristic maps for the spray characteristics and performance parameters showed that the aerodynamic Weber number and the liquid-air momentum flux ratio were associated with the liquid primary breakup, and the liquid-air momentum flux ratio and Rossby number were closely correlated with the liquid ejection mode.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.15 no.4
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• pp.261-267
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• 2003

The present study investigates the fire suppression characteristics using a water mist fire suppression system. Numerical simulations of fire suppression with water mist are performed with considering the interaction of fire plume and water droplet, droplet evaporation, and combustion of pool fire. The predicted temperature fields of smoke layer are compared with that of measured data. Numerical results agree with the experimental results within 5$^{\circ}C$ in the case without water mist In the case of fire suppression with water mist, numerical results dose not predict well lot temperature field in the gradual cooling region after water mist injection. But the predicted results of initial fire suppression are in good agreement with that of measured data. The reason of the discrepancy between predicted and measured data is due to the variation of turning rate during the injection of water mist. The effect of burning rate on the fire suppression is left as future study.

• Journal of ILASS-Korea
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• v.19 no.2
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• pp.88-93
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• 2014

Nanofluids is that metallic or nonmetallic nanometer-sized particles are dispersed in liquid and they can be used in various fields to increase the heat transfer rate. This study conducted experiments to evaluate whether the cooling efficiency of nanofluids is better than that of water in spray cooling. A heated surface was designed and fabricated to make the temperature distribution be linear, which was confirmed by three thermocouple measurements under the heated surface. Spray cooling experiments were conducted using water, 0.2% wt. (weight), and 0.5% wt. $Al_2O_3$ nanofluids at the pressure of 0.2 MPa and 0.3 MPa. Based on the results, it is shown that the cooling efficiency of nanofluids is higher than that of water especially in the region of single phase heat transfer. As a result, we can expect that nanofluids can be used as efficient coolants in the cooling of electronic packages where the temperature of the heated surface is not high enough for boiling incipience.

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

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2000.02a
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• pp.215-220
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• 2000

• Proceedings of the Materials Research Society of Korea Conference
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• 2000.11a
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• pp.79-79
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• 2000

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2001.11a
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• pp.326-331
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• 2001