백드래프트의 중력흐름에 미치는 구획실 내부 초기조건 및 개구부 형상의 영향 = Effects of Initial Condition and Opening Geometry of a Compartment on the Gravity Current in the Backdraft

다국어 초록 (Multilingual Abstract)

Computational study of a gravity current prior to the backdraft was conducted using fire dynamic simulator (FDS). Various initial conditions of mixture compositions and compartment temperature as well as four opening geometries (Horizontal, Door, Vertical, and Full opening) were considered to figure out their effects on the gravity current. The density difference ratio (beta) between inside and outside of compartment, the gravity current time (t_{ grav}) and velocity (v_{ grav} ), and non-dimensional velocity (v^{ *}) were introduced to quantify the flow characteristics of the gravity current. Overall fluid structure of the gravity current at the fixed opening geometry showed similar development process for different beta conditions. However, t_{ grav}for entering air to reach the opposed wall to the opening geometry increased with beta. Door, Vertical, and Horizontal openings where openings are attached on the ground showed similar development process of the gravity current except for Horizontal opening, which located on the middle of the opening wall. The magnitude of v_{ grav} at fixed beta was, from largest to smallest, Full > Vertical > Door > Horizontal, but it depended on both the size and location of the opening. On the other hand, v^{ *} was found to be independent to beta, and only depended on the geometry of the opening.

참고문헌 (Reference)

1 J. -W. Park, "The Effects of Radiation and Chemical Reaction Mechanism on the Development of Backdraft in a Compartment" 91-92, 2013

2 R. Yang, "Subgrid Scale Laminar Flamelet Model for Partially Premixed Combustion and Its Application to Backdraft Simulation" 40 : 81-98, 2005

3 W. G. Weng, "Study on Salt Water Modeling of Gravity Currents Prior to Backdraft using Flow Visualization and Digital Particle Image Velocimetry" 33 : 398-404, 2002

4 W. G. Weng, "Study on Effect of Opening Location on The Occurrence of Backdraft" 95-103, 2004

5 W. G. Weng, "Prediction of the Formation of Backdraft in a Compartment Based on Large Eddy Simulation" 22 : 376-392, 2005

6 C. M. Fleischmann, "Numerical and Experimental Gravity Currents Related to Backdrafts" 33 : 21-34, 1999

7 S. A. Ferraris, "Large Eddy Simulation of the Backdraft Phenomenon and its Mitigation in Compartment Fires with Different Opening Geometries" 181 : 853-876, 2009

8 S. A. Ferraris, "Large Eddy Simulation of the Backdraft Phenomenon" 43 : 205-225, 2008

9 J. -W. Park, "Investigation of Combustion Model for the Simulation of Backdraft in a Compartment" 60-61, 2013

10 박지웅, "FDS를 이용한 구획실 백드래프트 현상의 수치적 재현성에 관한 연구" 한국안전학회 28 (28): 6-10, 2013

11 J. D. McBryde, "Experimental and Numerical Modelling of Gravity Currents Preceding Backdrafts" Canterbury University 2008

12 J. -W. Park, "Effect of Initial Fuel Concentration on the Occurrence of the Backdraft" 41-, 2015

13 W. G. Weng, "Critical Condition of Backdraft in Compartment Fires : A Reduced-Scale Experimental Study" 16 : 19-26, 2003

14 J. -W. Park, "Computational Visualization of the Backdraft Development Process in a Compartment" 18 : 25-29, 2015

15 J. -W. Park, "Computational Study of the Initial Condition and Development of Backdraft in a Compartment" 29-32, 2013

16 J. -W. Park, "Computational Study of Backdraft Dynamics in the Compartment" Pukyong National University 2014

17 C. M. Fleiscmann, "Backdraft Phenomena" University of California 1993