• The KSFM Journal of Fluid Machinery
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• v.9 no.2 s.35
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• pp.59-63
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• 2006

• 유체기계공업학회:학술대회논문집
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• 2005.12a
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• pp.765-767
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• 2005

• 유체기계공업학회:학술대회논문집
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• 2005.12a
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• pp.681-681
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• 2005

• 유체기계공업학회:학술대회논문집
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• 2004.12a
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• pp.232-239
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• 2004

• Fire Science and Engineering
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• v.33 no.3
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• pp.37-43
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• 2019

In this study, ethanol pool fire extinguishing experiments were conducted using a twin-fluid nozzle. Ethanol pool fires, 5.027×10^-3 ㎡ and 1.131×10^-2 ㎡ in size (80 mm and 120 mm in fuel pan diameter, respectively), were tested, and the flow 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 ㎡ and 1.131×10^-2 ㎡ in size were measured to be 1.01 kW and 5.51 kW, respectively. For both fire source cases in the present experimental range, regardless of the water flow rates, the ethanol fires were extinguished successfully under the high air flow rate condition (e.g., above 40 L/min). On the other hand, under all water flow rate conditions, the fire extinguishing time and water consumption decreased with increasing air flow rate, which were approximately 23 s and 185 g under high air flow rate conditions (e.g., above 50 L/min), respectively. Based on the water consumption per heat release rate, the present experimental data were compared with the previous ones using a single-fluid nozzle, and it was found that the twin-fluid nozzle could extinguish a fire with a lower water consumption than a single-fluid one.

• Fire Science and Engineering
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• v.32 no.3
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• pp.35-41
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• 2018

Experiments were performed on 140 ml hexane pool fire extinguishment using a twin-fluid nozzle. For this pool fire, the area of the fire source (round shape of 80 mm in diameter) was $0.005027m^2$ and the measured heat release rate was 2.81 kW. The flow rates of water and gas (air and nitrogen) supplied to the twin-fluid nozzle were 156-483 g/min (~0.156-0.483 l/min) and 30-70 l/min, respectively. In the present experimental ranges, the high gas flow rate conditions led to the successful extinguishing of the pool fire. Under the low gas flow rate conditions in the extinguishment regime, the extinguishment time was long and the estimated water consumption was high. Under high gas flow rate conditions, however, the water flow rate conditions did not appear to have a great impact on the extinguishment time and estimated water consumption. On the other hand, in the present experimental ranges, the types of supply gas did not appear to affect the extinguishable flow rate condition, extinguishment time, and estimated water consumption. Finally, using the present experimental results with previous ones using a single-fluid nozzle, the water consumption of twin-fluid and single-fluid nozzles for extinguishing a 140 ml hexane pool fire were preliminarily compared and discussed.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.382.2-382.2
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• 2016

현재 전 세계적으로 에너지 소비가 급격히 증가하고 있다. 하지만 급격한 에너지 소비에 따른 자원 및 에너지 공급의 불확실성은 점점 높아지고 있다. 특히, 우리나라는 공급 에너지의 96.4%를 해외 수입에 의존하고 있기 때문에 에너지 안보에 매우 취약한 구조를 갖고 있다. 그리고 열전달 시스템에서 임계 열유속은 열전달 시스템의 한계를 나타낸다. 따라서 임계 열유속의 향상은 열전달 시스템의 안전성의 향상을 위한 필수적인 요소이다. 이에 따라 다양한 산업에서 열전달 시스템을 통하여 막대한 양의 에너지가 소비됨에 따라 우수한 열전달 특성을 가진 나노유체를 사용하여 열전달 시스템의 효율 및 안정성을 높이고자 하는 많은 연구가 진행되고 있다. 따라서 본 연구에서는 유동 비등에서 그래핀 나노 유체 사용에 따른 열전달 특성을 분석하였다. 유동 비등에서 0.01 vol%의 산화 처리된 그래핀 나노유체를 사용하였을 경우 유속이 증가함에 따라 임계 열유속은 증가하였으며 유속이 증가함에 따라 비등 열전달 계수도 증가함을 확인하였다. 그리고 임계 열유속은 순수 물보다 최대 66.32% 증가하였으며, 비등 열전달 계수는 풀비등에서 보다 최대 28.14% 증가함을 확인하였다.

• 한국전산유체공학회:학술대회논문집
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• 2010.05a
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• pp.451-455
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• 2010

In this study, the various supply system of LRE such as a feed-line, an elbow, and an orifice as a part of integrated analyzing has been combined to develop the performance analysis program. Computational analysis has been used to compare the results and to verify the validity and limitation conditions of the performance analysis program by changing orifice positions.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.12
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• pp.3567-3573
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• 2009

This research proposed a dashpot type mount design using MR fluids, and investigated experimentally the influence of the design parameters of the dashpot MR fluid mount, which affect the damping forces of the dashpot MR fluid mount. In order to observe the influence, the dashpot MR fluid mount which have the different effective length and the core structure is manufactured. The variations of the resistance forces according to different effective lengths of the magnetic pole of MR fluid mount, along which magnetic field is defined, was investigated. It was founded that the resistance forces from the MR mount decreased with increased input frequencies, while increased with increased applied electric current intensities. Nevertheless, there is no appreciable change in the resistance forces with respect to the effective length variations of the magnetic pole of MR fluid mount.

• Fire Science and Engineering
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• v.33 no.5
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• pp.28-36
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• 2019

In the present study, the effects of supply gas and water mist on the heptane pool fire extinguishing performance were investigated using the full cone and hollow cone twin-fluid atomizers. Air or nitrogen of 30 lpm (Liter per minute; L/min) was used as the supply gas, and the experiments were conducted under the water flow rate conditions of 0 lpm (i.e., discharge of air or nitrogen only) and 0.085 lpm (i.e., discharge of water mist with supply gas). Experimental results confirmed that the use of water mist discharge with the supply gas and full cone spray pattern reduced the fire extinguishing time as compared to that of only supply gas discharge and hollow cone spray pattern. In addition, for the discharge of water mist using the full cone twin-fluid atomizer, water mist significantly affected fire extinguishing performance, whereas the effect of the supply gas was less pronounced. On the other hand, for the discharge of water mist using the hollow cone twin-fluid atomizer, the fire extinguishing time was remarkably reduced by the supply of nitrogen, as compared with that of air, indicating that the supply gas as well as water mist can significantly affect fire extinguishing performance.