• 한국화재소방학회논문지
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• 제34권4호
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• pp.7-12
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• 2020

본 연구에서는 미세물분무의 특성이 열복사 감쇠에 미치는 영향을 살펴보기 위한 수치해석 연구를 수행하였다. 고온의 복사 패널로부터 전파되는 열복사가 미세물분무를 통과하여 약화되는 과정을 FDS를 이용하여 해석하였고, 미세물분무의 분사유량, 액적평균입경과 분무각에 따른 영향을 분석하였다. 해석 결과로부터 분사유량의 증가와 액적크기의 감소가 열복사 감쇠 효과를 증가시키는 것을 알 수 있었다. 복사열이 통과하는 분무 공간 분포의 영향을 살펴보기 위해 분사각을 변화시켜 열복사 특성을 분석하였으며 분사각이 클수록 복사 감쇠 효과가 커지는 것을 확인하였다. 이것은 유사한 액적크기분포와 유량조건에서도 액적들이 공간적으로 더 넓게 퍼져 있는 경우 복사의 감쇠 효과가 더 커질 수 있음을 보여준다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2005년도 학술발표회(1)
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• pp.681-682
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• 2005

• 한국안전학회지
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• 제16권2호
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• pp.13-21
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• 2001

The effect of water spray for the fire sprinkler depends on droples distribution over maximum possible floor area. The present study are carried out for the characteristics of water spray and droplets experimentally and numerically km two fire sprinkler heads which are CHM head and CHl heal CHl head is self-production and CHl head is widely used up to date. As the result of using CHM head, water spray and droplets are distributed over large area because CHM head has smooth surface and non-flamed shape. When the pressure of fire sprinkler head is low, SMD(sauter mean diameter) is large and when the pressure of fire sprinkler head is high, SMD is small.

• 한국수산과학회지
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• 제38권1호
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• pp.65-69
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• 2005

We have developed a new method of manufacturing salts by horizontal spray drying technique, using the concentrated deep ocean water after desalination processes. We studied the chemical characteristics of the spray-dried salts. Sodium content in the spray salts is $28.4\%$, which is $10-30\%$ lower than that of bay salts, bamboo salts and boiling salts $(32-38.2\%)$. However, the contents of magnesium, potassium and calcium of the spray salts are 2.5 times, 3 times and 4.5 times higher relative to those of bay salts, respectively. On the one hand, sulfur content in spray salts is 14 times lower than those of bay salts, which is caused by their volatilization during spray and vaporization of the concentrated seawater. Enrichment factors of Mg (0.8), K (0.9) and Ca (1.0) in the spray salts are relatively higher than those in bay salt (0.2-0.3), bamboo salt (0.15-0.4) and boiled salt (0.4-0.7), respectively. On the contrary, enrichment factor of sulfur in spray salts is observed to be 0.07, which is considerably lower than those in other salts (0.3-0.7). It means that the minerals like Mg, K and Ca can be well conserved from seawater to salts through spray drying techniques, while volatile elements like sulfur, lead, mercury and organic compounds can be easily removed from seawater via spray and heating processes.

• 한국분무공학회지
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• 제23권1호
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• pp.30-35
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• 2018

The objective of this study is to predict numerically the effect of intake humidification on the injected diesel fuel spray characteristics in a compression ignition engine. In this work, Wave model and Ducowicz model were applied as the break-up model and evaporation model, respectively. The amount of water vapor for the humidification was changed from 0% to 30% of injected fuel mass. The number of applied meshes was generated from 49,000 to 110,000. At the same time, the results of this work were compared in terms of spray tip penetration, SMD and equivalence ratio distributions. It was found that the cylinder temperature and cylinder pressure were decreased with increasing water vapor mass by vaporization latent heat and specific heat, however, the difference was very small. So, the spray tip penetration was not different by water vapor mass. Also, higher equivalence ratio distributions were observed with increasing water vapor mass by the improvement of fuel atomization.

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

• Journal of Advanced Marine Engineering and Technology
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• 제22권6호
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• pp.880-887
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• 1998

In order to study heat transfer characteristics of spray cooling for the purpose of uniform and soft cooling of high temperature surface a series of experiments for a hot horizontal copper flat plate was performed by downflow spray water using flat spray nozzle. Cooling curves were mea-sured under the various experimental conditions of flow rates and temperatures of cooling water Surface temperature surface heat fluxes and heat transfer coefficients of horizontal upward-facing flat surface were calculated with cooling curves measured at each radial positions near the cooling surface by TDMA method. Generally heat transfer characteristics for spray cooling is simi-lar to boiling phenomenon of pool boiling. The minimum heat flux(MHF) appear at the surface temperature of about ${\Delta}Tsat=250^{\circ}C$ and the critical heat flux(CHF) appear at about ${\Delta}Tsat=250^{\circ}C$.

• 대한기계학회논문집
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• 제6권3호
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• pp.256-260
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• 1982

This paper presents the characteristics of fuel spray in a diesel engine. In this paper, in order to obtain spray droplet size in a diesel engine, water was injected into the cylinder at room temperature and pressure by injection system. Spray droplet size was measured by liquid immersion technique with a lubricant used as an immersion liquid for spray water from injection nozzle. In this experiment, single hole type throttle nozzle are used at same operating conditions, which included opening pressure of nozzle, fuel delivery, and injection speed. Sauter mean diameter decrease with the increase of injection pressure and decrease in injection nozzle diameter. The rate of spray penetration increased with increasing injection pressure and diameter of injection nozzle at the constant spray conditions.

• 대한기계학회논문집B
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• 제20권2호
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• pp.624-631
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• 1996

가솔린 화재의 소화과정을 규명하기 위하여 부력과 순수확산에 의해서만 연료와 산화제가 혼합되는 순수확산화염을 대항으로 수분무에 의한 소화실험을 체계적으로 수행하여 다음과 같은 결론을 얻었다. 1) 수분무는 특정 조건에서 수분무가 없을 때인 자연연소상태에 비하여 더 높은 값의 연소율을 가지게 되어, 오히려 화재의 연소를 촉진하게 된다. 2) 수분무시 연소율은 자연연소상태보다 더 높은 값으로 증가하다가 어느 순간 연료표면의 냉각조건이 충분히 이루어지면 소화기 일어나게 된다. 30 수분무에 의해 유입되는 공기는 분무 자체와 함쎄 화염을 반경방향으로 흐트러지게 함으로써 연료와 공기와의 접촉면적을 증대시켜 연소를 촉진하는 반면, 분무수가 연료 표면에 쉽게 도달할 수 있도록하여 연료표면을 보다 잘 냉각시키게 된다. 즉 주위공기의 유입은 연소율의 증가 및 감소에 영향을 미친다. 4) 본 실험조건에서는 분무수의 입경이 약 40.mu.m 이하인 액적들은 화염구역내에서 증발하거나 그 경로가 바뀌어 연료 표면에 도달되지 못함을 발견하였다. 5) 본 연구와 같이 주로 냉각작용에 의하여 화염이 소화되는 경우에는, 화염자체의 냉각효과 보다는 연료표면의 냉각에 의한 효과가 지배적임을 알 수 있었다.

• 한국자동차공학회논문집
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• 제10권4호
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• pp.60-68
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• 2002

Experiments have been conducted to investigate the effects of emulsified fuels on the spray characteristics and exhaust emissions in a diesel engine. Four different fuels were examined : diesel, emulsified fuels with water contents which were varied with 13, 15, and l7wt%. Characteristics of fuel spray were measured by an optical method, PLLIF(planar liquid laser induced fluorescence). Compared to diesel fuel, emulsified fuels which had relatively high kinematic viscosity showed smaller spray angle and longer spray tip penetration. The qualitative droplet distributions of emulsified fuels showed worse atomization process than that of diesel fuel. As the water contents were increased, PM and NOx could be reduced simultaneously. It was specially noted that the emulsified fuel with l7wt% water content was found to be the best in reducing rates, NOx 30% and PM 40%.