[논문]LES-VoF를 이용한 소방용 스프링클러 헤드의 보스 및 디플렉터 치수에 따른 1차 분열 특성 분석

김태훈

doi:10.15435/jilasskr.2021.26.3.127

LES-VoF를 이용한 소방용 스프링클러 헤드의 보스 및 디플렉터 치수에 따른 1차 분열 특성 분석
Analysis of Primary Breakup Characteristics Depending on the Boss and Deflector Dimension of Fire Sprinkler Head using LES-VoF 원문보기

한국분무공학회지 = Journal of ilass-korea, v.26 no.3, 2021년, pp.127 - 134

김태훈 (서울과학기술대학교 안전공학과)

Abstract ▼ AI-Helper

Fire sprinkler initial spray was analyzed by Large eddy simulation (LES) and Volume of Fluid (VoF) integrated method. The IsoAdvector geometric VoF was used to identify the liquid-gas interface clearly even with the large Courant-Friedrichs-Lewy number. To reduce the computational costs, sector meshes and Adaptive Mesh Refinement up to level 3 were used. Base mesh size was 1 mm, which is roughly equivalent to the initial sprinkler droplet. Top surface radius of boss and deflector size were modified to investigate the effects of sprinkler head design on primary breakup process. When top surface radius of boss was increased, vertical liquid sheet was formed. This phenomenon reduced the sheet breakup radius, sheet thickness and velocity. Due to reduced liquid sheet thickness, a large amount of ligaments was created from the liquid sheet. As a result, there was a dramatic decrease in volume per surface area, indicating an increase in breakup process. Spray pattern viewed in radial direction also changed when top surface radius of boss increased. When top surface radius of boss was increased, a T-shaped pattern was observed while a V-shaped pattern was observed in all other cases. When the deflector size increases, the spray pattern remains V-shaped, even if the top surface radius of boss increased. Further studies on promoting atomization of the water supplied to the lower part of the sprinkler head in the T-shape pattern should be conducted.

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표/그림 (11)

그림 Fig. 2 Geometry of computational domain
그림 Fig. 1 Reference sprinkler head
표 Table 1 Fluid properties applied to simulation
표 Table 2 Sprinkler head geometry
$Fig. 3 Isosurface of volume fraction for various grid size (α = 0.32, case 1)$ 그림 Fig. 3 Isosurface of volume fraction for various grid size (α = 0.32, case 1)
$Fig. 4 Isosurface of volume fraction for various sprinkler head design (α = 0.32, case 2-4)$ 그림 Fig. 4 Isosurface of volume fraction for various sprinkler head design (α = 0.32, case 2-4)
그림 Fig. 5 Minimum sheet breakup radius measured and predicted by Huang model⁽¹¹⁾
그림 Fig. 6 Sheet thickness measured and predicted by Zhou model⁽¹³⁾ and Watson model⁽¹²⁾
그림 Fig. 7 Maximum velocity at deflector tip and sheet velocity predicted by Watson model⁽¹²⁾
그림 Fig. 8 SMD at r = 0.14 m and volume per unit area of whole domain
그림 Fig. 9 Accumulated water flux during 0.005 s

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