• 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.

• 한국분무공학회지
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• 제16권2호
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• pp.90-96
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• 2011

Atomized liquid jets from the washing nozzle which configured with recirculation chamber for cleaning hot-zone area are accelerated and impinged on the head lamp surface. Cleaning efficiency of head lamp can be increased with injecting washing fluids into the hot-zone area. Experimental and numerical studies with various design parameters were executed to reveal the relations between internal geometry and internal flow in the washing nozzle. Spray structures were fitted with each of the head lamp surfaces and spray nozzles were optimized to the spray pattern. The recirculation chamber induces a recirculation flow and can be decreased the pressures perturbation inside the chamber. Orifice determines the mass flow rate. When the diameter of orifice is excessively large, it showed an unstable spray pattern. As a nozzle exit angle increases, density distributions are separated with two section. Also, as a protrusion length of nozzle exit increases, spray patterns are spread into a large area and density distributions showed unstable trend.

• 한국분무공학회지
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• 제28권2호
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• pp.97-104
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• 2023

A sprinkler is a fire suppression system that extinguishes combustible materials in the early stages of a fire, creating a spray. However, spray formation method of the sprinkler can result in an uneven distribution of water spray on the surface of combustible materials. It is necessary to ensure a consistent water flux density regardless of the spray direction and angle. In this study, the water flux distribution was analyzed for the various types of sprinkler head: circular, flush, pendent, and upright types. All sprinkler heads have a K-factor of 80 LPM/(0.1MPa)^0.5. In this study, water collection cubes were used to examine the water flux distribution. The upright type sprinkler head showed a low standard deviation in total sprayed area, indicating a high level of uniformity. The upright type head showed the lowest standard deviation in the radial direction, and also showed the lowest standard deviation in the azimuthal direction. Upright sprinkler head has no obstructing structure along the path of droplets after they are generated. For this reason, upright sprinkler head showed the most uniform water flux distribution on the floor.

• 한국자동차공학회논문집
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• 제11권4호
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• pp.22-28
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• 2003

Predictions of the fuel spray dispersion and mixing processes are very important to improve the fuel consumption and exhaust emissions in GDI engines. Numerical and experimental analysis of the sprays with a swirl injector have been conducted. A numerical analysis is carried out using KIVA-II code with modified spray models. Experimental measurements are performed to show the global spray images and the local images near nozzle tip using laser sheet visualization technique. Computed and measured spray characteristics such as spray width, tip penetration are compared, and good agreements can be achieved. The spray head vortex is stronger as the injection pressure increases, but numerical calculations cannot show the head vortex properly.

• 한국화재소방학회논문지
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• 제31권3호
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• pp.54-62
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• 2017

본 연구는 랙크식 창고에 적용되고 있는 인랙스프링클러의 살수특성을 알아보기 위해 수행되었다. 국내산 헤드와 미국산 헤드를 대상으로 흐름성능실험, 방사각도 측정, 각도별 밀도측정 등이 수행되었다. 국내산 헤드의 경우 넓은 방사범위를 가지고 있으며, 미국산 헤드의 경우 국내산 헤드에 비하여 좁은 각도를 가지고 있다. 동일한 K80헤드로 비교해보면 국내산 헤드는 직접 살수가 어려운 부분으로 물을 보낼 수는 있으나, 각도별 살수밀도는 낮은 수준이었다. 미국산 헤드는 상대적으로 좁은 각도 내에 국내산에 비하여 많은 량의 물을 보낼 수 있는 것으로 나타났다. 결론적으로 랙크식 창고의 평면적으로 2열 이상으로 배치된 가연물에 대해서는 화재확산을 억제하거나 진압 효과를 가지기 위해서는 페이스 스프링클러의 도입과 함께 지그재그 형태로의 배치를 통해 살수장애지역을 최소화 해야 할 것으로 보인다.

• 한국화재소방학회논문지
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• 제18권4호
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• pp.35-41
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• 2004

스프링클러 헤드의 살수 특성은 화재의 초기 진화 성능을 결정짓는 매우 중요한 요소이며, 이는 헤드노즐의 형상에 크게 좌우된다. 본 연구에서는 국내 시장점유율이 가장 높은 4개 제조사의 헤드 제품군에 대하여 방수계수 값과 방향성 살수 분포 특성을 규명하였다. 방수계수는 모두 기준 값을 상회하였지만, 헤드 종류별로 동일한 설계 값을 가짐에도 불구하고 큰 차이를 보이는 것으로 나타나 제품 간 품질차이가 큰 것으로 나타났다. 다만, 방수계수는 압력변화에 관계없이 비교적 일정하게 나타났다. 방향별 살수 분포 특성은 일부 헤드 샘플의 경우 매우 심각한 편향 분포를 나타냄으로써 성능개선 연구가 시급한 것으로 판단되었다

• Journal of Mechanical Science and Technology
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• 제16권4호
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• pp.557-563
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• 2002

In this paper, the characteristics of flow and spray motions affected by from piston head configurations were investigated numerically. Calculations were carried out from intake process to the end of compression. GTT (Generalized Tank and Tube method) code, which includes a third order upwind Chakravarthy-Osher TVD scheme and k-$\varepsilon$ turbulence model with fuel spray analysis was used for the calculations. As a results, piston heads with smaller radii of curvature were found to give stronger reverse tumble than those with larger radii of curvature. Similar results are shown in the convection and diffusion of fuel sprays.

• International Journal of Automotive Technology
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• 제6권1호
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• pp.9-14
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• 2005

An experimental investigation has been carried out to reveal the atomization process of the diesel fuel spray. The spray injected through a single hole nozzle was taken by a camera on the opposite side of a stroboscope for macroscopic observation or a nanolite for microscopic observation. The effect of nozzle aspect ratio was analyzed with disintegration phenomena of the diesel spray. Based on the enlarged spray photograph, atomization process was observed in detail and further the spray cone angle was measured under various ambient pressures. The result shows that atomization of diesel spray in early stage of injection is mainly progressed in the vicinity of spray periphery region except the region close to the nozzle exit and spray head region. The spray cone angle is nearly constant under the pressurized condition, while it decreases with elapsing time under the atmospheric condition.

• 대한후두음성언어의학회지
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• 제29권2호
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• pp.79-82
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• 2018

Background and Objectives : Laryngeal contact granuloma is benign inflammatory disease induced by excessive mechanical contact of larynx such as endotracheal intubation, voice abuse, laryngeal microsurgery as well as laryngopharygeal reflux. Because it is caused by various risk factors, multiple treatment modalities are required. The purpose of study is to evaluate treatment effect of topical steroid through nasal cavity in contact granuloma. Materials and Method : Fifty-two patients were enrolled in this study with exception of intubation granuloma. Patients were classified with four groups (Proton pump inhibitor (PPI), Nasal steroid spray (SPR), PPI+SPR, Observation) according to treatment modality. Results : Patients who treated with PPI (Odds ratio 2.45, p=0.03) and combination of PPI and SPR (Odds ratio 2.88, p<0.01) had significantly better response than patients who not treated with medical therapy. Conclusion : Combination therapy of nasal steroid spray and PPI is effective for contact granuloma of larynx and considered as a treatment of choice rather than PPI only treatment.

• EDISON SW 활용 경진대회 논문집
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• 제4회(2015년)
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• pp.606-611
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• 2015

초기 화재 진압을 위해 사용되는 스프링클러(sprinkler) 설비는 스프링클러헤드의 형태에 따라 살수 분포가 달라진다. 화점의 발생 위치는 특정하기 어려우므로 스프링클러의 살수범위(spray coverage)가 넓게 퍼지는 형태가 되는 것이 확률적으로 가장 큰 효율성을 가진다. 본 연구에서는 EDISON_전산열유체 시스템의 다상유동 해석자를 활용하여 스프링클러헤드의 형태에 따라 살수각과 국부 유동장을 분석하였다. 3차원 형상을 가지는 스프링클러헤드 형상을 2차원 단면으로 나누어 해석하였으며 프레임(frame)과 반사판(deflector)의 형상에 따른 유동장의 변화를 살펴보았고 살수각(spray angle)을 정량적으로 나타내었다. 최종적으로 최대 최소의 살수각을 갖는 2차원 스프링클러헤드를 형상화하였고 이를 중첩하여 살수 범위를 넓게 갖는 스프링클러헤드를 3차원 모델링하였다.