물과 공기가 공급되는 2유체노즐을 활용한 에탄올 풀화재 소화 실험

정찬석,이치영 한국화재소방학회 2019 한국화재소방학회논문지 Vol.33 No.3

In this study, ethanol pool fire extinguishing experiments were conducted using a twin-fluid nozzle. Ethanol pool fires,5.027×10-3 m2 and 1.131×10-2 m2 in size (80 mm and 120 mm in fuel pan diameter, respectively), were tested, and theflow rates supplied to the twin-fluid nozzle for fire extinguishing were 156-483 g/min and 20-70 L/min for water and air,respectively. The heat release rate increased with increasing fire source area, and heat release rates of 5.027×10-3 m2 and1.131×10-2 m2 in size were measured to be 1.01 kW and 5.51 kW, respectively. For both fire source cases in the presentexperimental range, regardless of the water flow rates, the ethanol fires were extinguished successfully under the high airflow rate condition (e.g., above 40 L/min). On the other hand, under all water flow rate conditions, the fire extinguishingtime and water consumption decreased with increasing air flow rate, which were approximately 23 s and 185 g under highair flow rate conditions (e.g., above 50 L/min), respectively. Based on the water consumption per heat release rate, thepresent experimental data were compared with the previous ones using a single-fluid nozzle, and it was found that thetwin-fluid nozzle could extinguish a fire with a lower water consumption than a single-fluid one. 본 연구에서는 2유체노즐을 이용하여 에탄올 풀화재(Ethanol pool fire) 소화 실험을 수행하였다. 화원 면적이 5.027× 10-3 m2와 1.131 × 10-2 m2(연료팬 직경은 각각 80 mm와 120 mm)를 대상으로 하였고, 화재 소화 실험 시 2유체노즐로의 공급 유량의 경우 물은 156-483 g/min, 공기는 20-70 L/min 조건이었다. 화원 면적이 증가하면 열방출률도 증가하였고, 화원 면적이 5.027 × 10-3 m2와 1.131 × 10-2 m2일 때의 열방출률은 각각 1.01 kW와 5.51 kW로 측정되었다. 본 실험 영역에서 2가지 화원 면적 조건 모두, 물 공급 유량 조건과는 상관없이 공기 공급 유량이 40 L/min 이상의조건에서 소화가 가능하였다. 소화 소요 시간 및 물 소모량의 경우 모든 물 공급 유량 조건에서 공기 공급 유량이증가함에 따라 감소하는 경향이 관찰되었고, 공기 공급 유량이 비교적 많은 영역(예를 들면, 약 50 L/min 이상)에서소화 소요 시간은 약 23 s, 물 소모량은 약 185 g 이내로 나타났다. 본 연구 결과와 단일유체노즐을 이용한 기존 연구간 단위 열방출률 당 물 소모량 비교를 통하여, 2유체노즐이 단일유체노즐에 비해 더 적은 물 소모량으로 소화가가능할 수 있음을 확인하였다.

2유체노즐의 액체풀 화재 소화 성능에 대한 검토

정찬석,이치영 한국화재소방학회 2017 한국화재소방학회논문지 Vol.31 No.4

In the present experimental study, the liquid pool fire extinguishment performance of twin-fluid nozzle was preliminarilyexamined. For the liquid pool fire, the ethanol of 1200 ml (volume) was prepared, and two kinds of air flow rate conditions(40 l/min and 70 l/min) were tested at the constant water flow rate condition of 632 ml/min. In the present experimentalranges, the fire extinguishment experiments were carried out using the twin-fluid nozzle and its spray characteristics (i.e., SMD(Sauter Mean Diameter) and flow distribution) were investigated. As a result, at the higher air flow rate, the liquid pool firewas extinguished quickly and successfully, which was discussed using the visualization and spray characteristics of twin-fluidnozzle. In addition, through the comparison with some of previous results, it was found that potentially, the twin-fluid nozzlecan extinguish the liquid pool fire under the smaller water flow rate condition, as compared with the single-fluid nozzle. 본 연구에서는 2유체노즐의 액체풀 (Liquid pool) 화재 소화 성능에 대하여 선행적인 검토를 수행하였다. 액체풀화재의 경우, 에탄올 (Ethanol) 1200 ml를 이용하였으며, 물 공급 유량은 632 ml/min, 공기의 공급 유량은 40 l/min과70 l/min으로 설정하였다. 본 실험조건에서 2유체노즐을 이용하여 화재 소화 실험을 수행하였고, 2유체노즐의 분사특성 (액적 크기 및 유량 분포)을 측정하였다. 실험 결과, 공기의 유량이 많은 조건에서 빠른 시간 안에 성공적으로화재를 소화할 수 있었고, 이러한 결과에 대하여 가시화 및 2유체노즐 분사 특성 데이터를 토대로 분석하였다. 또한,기존 연구의 일부 결과와 비교를 통하여, 2유체노즐이 단일유체노즐에 비해 더욱 작은 물의 유량 조건에서도 화재소화를 할 수 있을 가능성이 있음을 확인하였다.

소규모 헥산 풀화재를 이용한 2유체노즐의 소화 특성에 대한 실험적 연구

정찬석,이치영 한국화재소방학회 2018 한국화재소방학회논문지 Vol.32 No.3

본 연구에서는 2유체노즐을 이용하여 140 ml 헥산 풀화재(Pool fire)에 대한 소화 실험을 수행하였다. 해당 풀화재의 화원(직경 80 mm인 원형) 면적은 0.005027 m2이고, 열방출률은 2.81 kW로 측정되었다. 물 공급 유량은 156-483g/min (~0.156-0.483 l/min), 기체(공기와 질소) 공급 유량은 30-70 l/min이었다. 본 실험조건에서 기체 공급 유량이 많은 경우에 성공적으로 소화가 가능하였다. 소화 가능 영역에서 기체 공급 유량이 적은 경우, 물 공급 유량이 많을때 화재 소화 소요 시간이 길었고, 물 소모량은 많은 것으로 나타났다. 반면, 기체 공급 유량이 많은 경우, 물 공급유량에 따른 화재 소화 소요 시간 및 물 소모량은 상대적으로 큰 차이가 없는 것으로 나타났다. 한편, 본 실험조건에서 공급 기체의 종류는 소화 가능 여부, 소화 소요 시간, 물 소모량에 큰 영향을 미치지 않는 것으로 측정되었다. 마지막으로 본 실험결과와 단일유체노즐을 이용한 기존 실험결과를 이용하여, 2유체노즐과 단일유체노즐의 140 ml헥산 풀화재 소화를 위한 물 소모량을 선행적으로 비교 및 검토하였다. Experiments were performed on 140 ml hexane pool fire extinguishment using a twin-fluid nozzle. For this pool fire, thearea of the fire source (round shape of 80 mm in diameter) was 0.005027 m2 and the measured heat release rate was 2.81kW. The flow rates of water and gas (air and nitrogen) supplied to the twin-fluid nozzle were 156-483 g/min (~0.156-0.483l/min) and 30-70 l/min, respectively. In the present experimental ranges, the high gas flow rate conditions led to the successfulextinguishing of the pool fire. Under the low gas flow rate conditions in the extinguishment regime, the extinguishment timewas long and the estimated water consumption was high. Under high gas flow rate conditions, however, the water flow rateconditions did not appear to have a great impact on the extinguishment time and estimated water consumption. On the otherhand, in the present experimental ranges, the types of supply gas did not appear to affect the extinguishable flow ratecondition, extinguishment time, and estimated water consumption. Finally, using the present experimental results with previousones using a single-fluid nozzle, the water consumption of twin-fluid and single-fluid nozzles for extinguishing a 140 mlhexane pool fire were preliminarily compared and discussed.

Effect of nozzle geometry for swirl type twin-fluid water mist nozzle on the spray characteristic

윤순현,김도연,김동건,김봉환 대한기계학회 2011 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.25 No.7

Experimental investigations on the atomization characteristics of twin-fluid water mist nozzle were conducted using particle image velocimetry (PIV) system and particle motion analysis system (PMAS). The twin-fluid water mist nozzles with swirlers designed two types of swirl angles such as 0°, 90° and three different size nozzle hole diameters such as 0.5mm, 1mm, 1.5mm were employed. The experiments were carried out by the injection pressure of water and air divided into 1bar, 2bar respectively. The droplet size of the spray was measured using PMAS. The velocity and turbulence intensity were measured using PIV. The velocity, turbulence intensity and SMD distributions of the sprays were measured along the centerline and radial direction. As the experimental results, swirl angle controlled to droplet sizes. It was found that SMD distribution decreases with the increase of swirl angle. The developed twin-fluid water mist nozzle was satisfied to the criteria of NFPA 750, Class 1. It was proven that the developed nozzle under low pressures could be applied to fire protection system.

Experimental Study of Discharge Coefficient with Non-Circular Effervescent Type Twin-fluid Nozzle

( Sang Ji Lee ),( Kun Woo Ku ),( Hyun Jin Yoon ),( Jung Goo Hong ) 한국액체미립화학회 2017 한국액체미립화학회 학술강연회 논문집 Vol.2017 No.-

An experimental study was carried out to investigate the injection characteristics of non-circular effervescent type twin-fluid nozzles. For this purpose, two types of non-circular nozzles (E1, E2) and one kind of circular nozzle (C) were used. Two types of nozzles were machined with similar area of exit orifice. Three types of aerorators with hole diameters of 1.2, 1.7 and 2.1 mm were used. Each aerorator has a total of 12 holes. It is expressed as Area ratio which is ratio of exit orifice area and aerorator hole area. At this time, the aerorator mounted on the nozzle used three different diameters to match the aspect ratio with the nozzle exit area. Therefore, experiments were performed according to three aspect ratios for each nozzle, and total experiments were conducted. Experiments were carried out by controlling the amount of air flowing after fixing the flow rate of the liquid, and then the nozzle internal pressure and the droplet size (SMD) were measured. The jet image was taken from the nozzles. The discharge coefficients of the three kinds of nozzles were compared with the conventional equation and the Jedelsky’s equation, and the Jedelsky’s equation was found to be about 4 times larger. In addition, empirical formula based on ALR, which is the largest variable in Jedelsky’s equation, was derived, and it was confirmed that the coefficient is almost the same regardless of the exit orifice type. SMD injected from the nozzle was confirmed to be smaller in the non-circular shape than in the circular shape, which is expected to be caused by the difference of the discharge coefficient values.

선택적 촉매 환원법을 위한 외부 혼합형 이유체 노즐 개발에 대한 실험적 연구

박정근 ( J. K. Park ),이충원 ( C. W. Lee ) 한국분무공학회 2004 한국액체미립화학회지 Vol.9 No.2

N/A The effect of the working fluid flow conditions and nozzle geometry on the spray performance of a twin-fluid nozzle used in Selective Catalytic Reduction is investigated experimentally. The liquid pressure is varied in the range of 0.3atm to 1.5atm and the air pressure is varied from the 0.5atm to 3.0atm. relative position between liquid nozzle(internal nozzle) and air nozzle(external nozzle) tip changes from 1mm inside the air nozzle to 1mm outside the air nozzle. The orifice diameter of the air nozzle is varied with 5㎜, 6㎜ and 7㎜. Spray visualization is realized with CCD-Camera. SMD(Sauter Mean Diameter) and mean particle velocities are measured by PDPA(Phase Doppler Particle Analyzer) under various experimental conditions. The measuring point is 300㎜ away from the nozzle tip in the downstream spray. The experimental results are that spray angle is depended air flow rate because nozzle diameter, air pressure and nozzle tip relative positions are related air flow rate. SMD is depended air flow rate and water flow rate. Also, SMD is increased when water flow rate is bigger. SMD is decreased when Air flow rate is bigger.

SCR용 외부혼합형 이유체 노즐개발을 위한 실험적 연구

이영진,박종원,이충원,석지권 朝鮮大學校 機械技術硏究所 2005 機械技術硏究 Vol.8 No.1

소각로 내에서 생성되는 질소 산화물을 저감시키는 SCR 설비의 핵심 기술이 되는 분사 노즐의 특성을 분석하고자 두 유체가 지나는 통로에 선회기가 달린 외부혼합형 이유체 노즐을 선정하여 물과 공기의 유량 및 압력 변화를 주었으며 외부노즐의 오리피스 직경의 변화와 두 노즐 선단부의 상대적인 변화를 주었다. 이와 같은 외부 혼합형 이유체 노즐의 장점은 다른 종류의 노즐을 사용할 때보다 더욱 미세한 액적을 얻을 수 있으며 액체의 유량이 변해도 일정한 형태의 분무각을 유지시켜 준다. 또한 액체의 압력이 기체의 압력보다 높은 경우에도 액체노즐에서 분사되는 액적이 기체 공급관으로 역류하는 일이 없으며, 기체의 압력이 액체의 압력보다 높아도 액체의 분사특성에 거의 영향을 주지 않는다. 그리고 공기가 선회기를 지나서 분사되기 때문에 더욱 활발한 와류가 생성된다. 따라서 분사 액적과 공기와의 혼합이 더욱 잘 이루어지리라 예상된다. 또한 거의 모든 분사압력범위에서 미립화가 잘 이루어지기 때문에 저압에서 고압으로 압력에 따른 분무 특성을 연구하기에도 적합하며 점도가 있는 물질의 분사에 특히 유효하므로 SCR 설비에 적합한 노즐로 사료된다. The effect of the working fluid flow conditions and nozzle geometry on the spray performances of a twin-fluid nozzle used in SCR(Selective Catalytic Reduction) is investigated experimentally. In this experiments, the liquid pressure is varied in the range of 0.3atm to 1.5atm and the annular air pressure is varied from the 0.5atm to 3.0atm. Relative position between liquid and air outlet port changes from 1mm inside the nozzle cap to 1mm outside the nozzle cap. The outer diameter of the air outlet port is varied with 5mm, 6mm and 7mm. Spray visualization is realized with CCD-Camera. SMD(Sauter Mean Diameter) and mean particle velocities are measured by PDPA(Phase Doppler Particle Analyzer) under various experimental conditions. The measuring point is 300mm away from the nozzle tip in the downstream spray. The experimental results are that spray angle is depended Air flow rate because Nozzle diameter, air pressure and nozzle tips relative position(nozzle tip) are related air flow rate. Also, SMD(sauter mean diameter) is depended Air flow rate and Water flow rate. SMD is increased when Water flow ratetwater pressure) is bigger. But SMD is decreased when Air flow rate (Air pressure) is bigger.

Y-jet 노즐의 설계인자와 SMD 측정방향에 따른 분무특성의 실험 연구

이상지,홍정구 한국분무공학회 2018 한국액체미립화학회지 Vol.23 No.4

Y-jet nozzle has various advantages over other twin-fluid nozzles and are used in industrial boilers. However, it costs large energy consumption because of assisted air and its design is complex. The Y-jet nozzle is consisted of a liquid and gas port and a mixing chamber. The diameter of the port and the length of the mixing chamber greatly affect spray and atomization characteristics, therefore, they are the most important factors in nozzle design. In this study, The experimental setup is consisted of a laboratory scale spray system. The characteristics of the Y-jet nozzle according to the design parameters were observed. As a result, it was found that the length of the mixing chamber did not have effect on the flow rate and the choking condition. The droplet size was measured using a Malvern type measuring device. In addition, measurements were conducted in the front and the right directions of the nozzles. Based on the results, the SMD View Ratio is defined. It is the asymmetrical design characteristics of the Y-jet nozzle.

Y-jet 노즐의 출구오리피스 형상이 비대칭 분무에 미치는 영향

백광열 ( Gwang Yeol Baik ),홍정구 ( Jung Goo Hong ) 한국분무공학회 2021 한국액체미립화학회지 Vol.26 No.1

Y-jet nozzle has a wide fuel flow rate range and turn-down ratio, thus, it is used in industrial boilers, furnace and agricultural atomizer. However, it has asymmetrical spray characteristics due to the nozzle design factors. Therefore, in this study, asymmetric spraying characteristics of the elliptical Y-jet nozzle was studied by using the lab-scale spray apparatus. As a result, the elliptical Y-jet nozzle had lower gas mass flow rate than circular Y-jet nozzle at same gas pressure, because of bigger shear stress due to the wider inner surface at the elliptical Y-jet nozzle. Larger SMD was measured on the elliptical Y-jet nozzle than the circular Y-jet nozzle. When SMD was measured in the X_Axis direction at the same gas mass flow rate, the elliptical Y-jet nozzle with an aspect ratio of 2:1 showed greater asymmetry than the others.

지하철 공기청정을 위한 2유체노즐형 자동세정 공기청정 시스템 개발에 관한 연구

안영철 ( Y. C. Ahn ),이재근 ( J. K. Lee ) 한국분무공학회 2004 한국액체미립화학회지 Vol.9 No.3

N/A 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.