The purpose of this study is to analyze the distribution characteristics of mist spray particle size by devising a rotary mist spraying device to develop the evaporative salt water desalination system. The rotary mist spraying device was consisted of a BLDC sirocco fan, a spinning fan, a fan fixed shaft and a salt water supply device etc. In this study we analyzed the characteristics of spray particle size and distribution according to the variation of sirocco fan surface roughness(Ra, μm), revolutions(rpm) and salt water flow rate(mL/min). When sirocco fan surface roughness( Ra) was in the range of 0.27~7.65 μm, the spray particle size was 0.117~1.360 μm. And then more than 90% of spray particles were found to be less than 0.50 μm. When sirocco fan surface roughness(Ra) was in the range of 12.70~22.84 μm, the spray particle size was 2.51~184.79 μm and more than 98% of spray particles were found to be less than 13.59 μm. To analyze the effect of fan rotation speed on the size and distribution of spray particles, when surface roughness Ra was fixed 0.27 μm and fan rotation speed and salt water flow rate was respectively changed at 3,800~5,600 rpm and 2.77~8.28 mL/min, spray particle size was 0.341~0.541 μm. And when salt water flow rate was 9.74 mL/min and fan rotation speed was 3,800~5,200 rpm, spray particle size was in the range of 29.29~341.46 μm and in case of 5,600 rpm more than 98.23% of spray particles were in the range of 2.51~13.59 μm.

컨테이너를 이용한 위험물의 해상운송이 증가함에 따라 적재불량으로 인한 위험물의 누설 등으로 선박에서 화재사고가 발 생하고 있다. 한편, IMO(MSC.93)에서는 2016년 1월 1일 이후 건조되는 개방갑판상에 컨테이너를 5단 이상 적재하도록 된 모든 선박은 물분무창(Water Mist Lance, WML)이라는 소화장치를 선박에 의무적으로 비치하도록 규정하였다. 본 연구에서는 LS-DYNA를 이용하여 최적의 첨단곡률반경을 가지는 WML을 설계하기 위한 수치해석을 수행하였다. 첨단부분의 길이가 10 mm, 15 mm, 20 mm인 3가지 모델에 대한 해석결과 길이가 15 mm인 경우만 컨테이너 벽면을 관통하고, WML의 첨단부분에 손상을 일으키지 않는 결과를 나타내었다. 향후, 본 연구결과를 바탕으로 테스트용 WML를 제작하여 성능실험을 할 계획이며, 문제점은 지속적으로 개선해 나갈 것이다.

This study developed a portable extinguishing equipment that can extinguish A-class, B-class fire. This equipment is made of Water Mist Gun, controlling board, decelerator, pump, engine, and etc,. This equipment is formed mist water when pressurized water with high pressure flows through a radial shape nozzle. As a result of several efficiency tests, it is developed nozzle and equipment that are not clogged, and improved the extinguishing efficiency. This developed equipment indicated a excellent effect of initial extinguishment of fire in a vulnerable area where it is difficult to approach such as temple, and traditional market.

In this study, the researcher investigated the effects of water mist nozzle shape on water mist according nozzle shape angle(=30°, 45°, 60°, 75° and 90°). It was found that the water mist spray with nozzle When exit angle of water mist nozzle is =90° as result examining about spray special quality of water mist, velocity distribution was expose to maximum. And temperature distribution of target plate was looked tendency that range low. Water mist spray system that consider in this research is one of the most important utilities providing water mist in order to supply fire extinguishing.

This research has so far found out problems including the second damage of extinguishant and the short time of emission when using the existing dry chemical extinguisher and gas type extinguisher, and impossibility of constant extinguishing due to the inability of recharge at the field. To solve such problems, a mobile water mist system was developed and used. However, it is judged that more improved mobile water mist system is necessary because the force of the fire changed diversely and remote villages in mountains or islands where the force of fire extinguishing is short or delayed, require high capacity of fire extinguishing. Therefore a new equipment was developed and tested focusing on the improvement of extinguishing capacity and the performance of extinguishing was found out to be improved, compared to the existing mobile water mist system. It also showed a superior extinguishing capacity to dry chemical extinguisher or gas type extinguisher. Afterward an additional research is required of simplification of equipment, price cutting and the development of additive to enable high performance even with just small extinguishant.

An experimental study of the fire protection performance of water mist spray subjected to thermal radiation was presented. Downward-directed water mist sprays to interact with an under. gasoline pool fire were experimentally investigated in underground environment. The mass mean diameters of water mist droplet were measured by PMAS under various flow conditions. The developed water mist spray nozzle was satisfied to the criteria of NFPA 750. The mechanism of the fire extinguishment by water mist spray was concluded to be cooling of the fire surface which lead to suppressed of' file1 evaporation. It was proved that the water mist spray system under. lower pressures could be applied to underground fire protection system.

This study analyzed the weather environment of the smart city to identify the temperature reduction effects of the heat reducing facilities. The methodology is divided into indoor and outdoor analyses. Indoor analyses were conducted for the evidence-based design of the facility. The size of nozzle is adjusted to derive the most efficient size for outdoor use. Three types of nozzles were used, 0.15 mm, 0.2 mm and 0.3 mm. The most efficient nozzle was selected as 0.15 mm. The outdoor test was measured for two days from August 3 to August 4, 2020, and the weather data were collected for the control and target sites on the first day. On the second day, the measurements were taken assuming that the temperature and humidity of two sites would be similar. Compared to the control group, the outdoor test site had a temperature reduction effect up to 7.4℃. When operating the heat-reducing facility, the rate of change in sensible temperature is lower than control site. This study concluded that mist facilities have a pre-cooling effect, which means reducing the temperature to a certain level. The results from this study data could be provided when establishing an adaptation policy for a heatwave.