• 대한조선학회논문집
• /
• 제59권2호
• /
• pp.80-88
• /
• 2022

A systematic experimental study is carried out for the fire fighting monitor nozzle of 65A diameter to design and manufacture a new nozzle with better water spray performance than available domestic nozzles. The nozzle inlet pressure, flow rate and reach for the discharged water from the nozzle are measured by utilizing the experimental facility consisting of two pumps and piping system with a flow meter and pressure gauges. It was found that the baffle position and baffle head chamfering were the most sensitive design factors to be remarkably changed in the flow rate of the discharged water. Also, It was confirmed that the baffle position and the water exit area had the significant effect on the change in reach distance. The results obtained from this study are expected to be used effectively to design new nozzles with excellent spray performances and also to validate numerical analysis results for evaluating the water spray performance of fire fighting monitor nozzles.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2015년도 추계 학술논문 발표대회
• /
• pp.34-35
• /
• 2015

Recently, introduction of Advanced water treatment facilities has been increasing due to serious domestic water pollution. Ozone is a strong oxidizing materials in the advanced water treatment facilities. However, due to such a strong oxidation, Ozone eroded waterproofing/corrosion on the concrete surface and caused performance degradation. Therefore, in this study, permeability experiment of metal spraying system by concrete surface treatment was conducted.

• 한국추진공학회:학술대회논문집
• /
• 한국추진공학회 2008년도 제31회 추계학술대회논문집
• /
• pp.175-178
• /
• 2008

심플렉스 연료노즐의 분무시험을 수행하였다. 가스터빈의 주 연료인 등유를 이용한 연료노즐 분무시험의 경우 폭발의 위험과 유해성으로 인하여 물을 이용하여 시험을 수행하는 경우가 많이 있게 된다. 본 연구에서는 ND:Yag 레이저를 이용한 가시화 시험과 PDPA 시스템을 이용한 입자 크기 측정 시험을 등유와 같은 특성을 가지는 Calibration Fluid Type # 2와 물을 작동유체로 사용하여 수행하였다. 시험결과에서 물의 SMD는 Calibration Fluid Type # 2 보다 5$\sim$15 mm 정도 크게 나타났으며 이는 물의 표면장력이 3배 정도 크기 때문으로 판단된다. 반면에 분무각과 분무형태는 유사하게 나타났다.

• 한국화재소방학회논문지
• /
• 제25권3호
• /
• pp.51-56
• /
• 2011

도로터널에서의 미분무수 소화시스템의 화재진압 특성을 조사하기 위해 실물 터널 화재 실험을 수행하였다. 적용된 소화시스템은 압력이 3.5 bar인 저압 물분무 소화설비와 60 bar인 고압 미분무수 소화시스템이다. 미분무수 소화시스템은 물분무 소화시스템의 1/6 만큼의 소화용수량을 사용한다. 화원 (fire source)은 실물 승용차와 유류화재를 모사한 화원면적 $1.4m^2$의 헵탄 연료 팬 화재로 구성하였다. 터널 내의 환기조건을 구현하기 위해 실물모형 터널의 한쪽 끝단에 유속(0.9~3.8 m/sec 범위) 발생장치를 설치하였으며, 화원에서 하류 방향으로 터널 내 온도분포는 K-type 열전대 트리를 사용하여 측정하였다. 실험 결과 고압 미분무수 소화시스템은 B급 화재의 경우 저압 물분무 시스템과 동등한 수준의 냉각효과를 보였다.

• 동력기계공학회지
• /
• 제2권1호
• /
• pp.25-30
• /
• 1998

In order to investigate the droplet size distribution and Sauter Mean Diameter in a ultra high pressure diesel spray, fuel was injected with ultra high pressure into the environments of high pressure and room temperature by an Electronic Hydraulic Fuel Injection System. Droplet size was measured with the immersion liquid sampling technique. The immersion liquid was used a mixture of water-methycellulose solution and ethanol. The Sauter Mean Diameter decreased with increasing injection pressure, with a decrease environmental pressure (back pressure) and nozzle diameter. Increasing the injection pressure makes the fuel density distribution of the spray more homogeneous. An empirical correlation was developed among injection pressure, air density, nozzle diameter and the Sauter Mean Diameter of spray droplets.

• 한국분무공학회지
• /
• 제3권4호
• /
• pp.50-57
• /
• 1998

The utilization of resonance should be considered to get the maximum effect of ultrasonic to atomize liquid. The ultrasonic generator, transducer, horn, and all attached parts are used to produce the resonance, and specially the characteristics of liquids such as liquid load, property, and etc., for the liquid atomization affinity are considered. In this study, the variable device of liquid load was made and distilled water and city water selected as experimental liquids were sprayed by a twin-fluid spray method and their diameters, distributions, and spray quantum of spray droplets were measured by the light scattering system. And all data were observed, compared and considered relatively. In results, a lot of phenomena of liquid atomization affinity by ultrasonic appeared in accordance with liquid loads, namely head h.

• 한국분말재료학회지
• /
• 제29권6호
• /
• pp.499-504
• /
• 2022

The objective of this study is to assess the impact of spray drying conditions on medium-chain triglyceride (MCT) loading, solubility, and release of an MCT-loaded solid self-emulsifying system in a water-insoluble oily substance. MCT-loaded solid self-emulsifying systems are prepared by spray drying with SDS and calcium silicate. The effects of inlet temperature (60, 80, or 100℃) and feed solution composition (0, 10, 50, 90, or 100% ethanol) on physicochemical properties of MCT-loaded solid self-emulsifying systems are studied. The inlet temperature significantly affects the water solubility of MCT. Moreover, the feed solution composition significantly affects water solubility, release rate, and MCT loading. The MCT-loaded solid self-emulsifying system obtained at 60℃ using 90% ethanol feed solution shows the best physicochemical properties among the synthesized products and exhibits better water solubility (4.43 ± 0.44 vs. 0 ㎍/mL) and release (94.4 ± 1.6 vs. 32.8 ± 7.4%, 60 min) than a commercial product. Furthermore, the MCT-loaded solid self-emulsifying system shows an excellent emulsion droplet size (approximately 230 nm).

• 대한안전경영과학회지
• /
• 제26권3호
• /
• pp.93-100
• /
• 2024

Outdoor storage fires have a significant impact on the surrounding environment, including adjacent storage facilities and buildings. Therefore, it is essential to review and manage the fire impact to minimize damage to human life and property on the outdoor storage fires. In this study, the heat release rate and radiant heat flux were simulated according to the fire time, wind veolcity, and presence or absence of water spray equipment in an outdoor storage facility fire, and the fire impact was analyzed. The outdoor storage was designed to simulate two scenarios on the outdoor storage fires containing gasoline, and FDS was used for fire simulation. As a results, when the water spray facility was not operating and the wind velocity was 5 m/s, the maximum radiant heat flux was 24.80 kW/m2, which exceeded the limit radiant heat flux of 20 kW/m2. When the water spray facility was operating and the wind veolcity was 10 m/s, the maximum radiant heat flux was 18.77 kW/m2, which did not exceed the limit radiant heat flux, indicating that the fire impact on adjacent storage facilities was relatively small.

• 한국추진공학회:학술대회논문집
• /
• 한국추진공학회 2008년 영문 학술대회
• /
• pp.255-259
• /
• 2008

This paper presents the spray characteristics of the oxidizer rich preburner injector which can be used in the high-thrust rocket system. We designed the basic shape of the liquid-liquid coaxial swirl injector for the rocket oxidizer rich preburner injection system. To understand the spray angle variation with the high pressure environment, the spray visualization in the high pressure chamber was preformed. Also we measured the droplet velocity, the Sauter Mean Diameter(SMD), the volume flux and the number density with the PDPA system by using water in atmospheric pressure. The results show that the spray angle is reduced by increasing ambient pressure and maximum droplet velocity is shown from a nozzle tip and then the droplet velocity decreases as a spray moves to the downstream. The SMD decreases on the axial distance from 20 mm to 50 mm but it increases over 50 mm. That is due to the increasing number of collision with each droplet and interaction with ambient air on going downstream direction.

• 한국분무공학회지
• /
• 제9권3호
• /
• pp.15-21
• /
• 2004

The removal of the dusts in the subway stations, tunnels, factories and buildings becomes issue for comfortable indoor and outdoor conditions. There has been used an automatic self-cleaning filter system to collect the dusts. In general, the collected particles are removed by water spray nozzles. The new design for improving the cleaning efficiency of collected dusts and reducing the supplied water is the concept of the plane array of demister filters and the twin-fluid nozzle for mixing compressed air and water in the automatic self-cleaning filter system. Results show that the cleaning efficiency of twin-nozzle filter systems is 99.1%, compared to 47% in the conventional filter system. Therefore the automatic self-cleaning filter system using twin-fluid nozzle filter systems reduces water supplied in the filter system, and increases cleaning efficiency and drying efficiency.