Semi-Empirical Model of Ceiling Jet in Tranquil Flow Region in Arched Ceiling Tunnel

• 발행기관: 한국화재소방학회
• 저자명: Yasushi Oka Aoi Tanno Chiaki Iwamoto Yoshiki Sakurai Hideyuki Oka
• 간행물 정보: 『International Journal of Fire Science and Engineering』Vol. 39, No. 2, 31~47쪽, 전체 17쪽
• 주제분류: 공학 > 공학일반
• 파일형태: PDF
• 발행일자: 2025.06.30

국문 초록

The present study focuses on the temperature and velocity of the smoke layer in the tranquil flow region of a naturally ventilated tunnel with an arched ceiling. Fire experiments were conducted using a laboratory-scale model tunnel with a height of 0.275 m, a floor width of 0.41 m and a length of 10 m. To predict the temperature at arbitrary positions within the tranquil flow region, the temperature attenuation equation, expressed as a weighted average of two exponential functions, is presented. A semi-empirical prediction formula is proposed to estimate the velocity attenuation of the smoke layer by combining approximate analytical solutions from a simplified theoretical model with laboratory-scale model tunnel experiments. Sub-models for estimating the variables included in the velocity attenuation prediction formula - such as the starting position of the tranquil flow region, the temperature rise at this position, and the smoke layer thickness - are also presented. These sub-models form a closed system of equations for the velocity attenuation equations. The vertical distribution of temperature in the smoke layer propagating in the tranquil flow region has a similar distribution shape regardless of the distance from the fire source. The velocity distribution also has the same characteristics. These distributions are described by applying the profile method. The proposed formulae are expected to be useful tools for smoke flow prediction, evacuation planning and disaster prevention planning in the event of a tunnel fire.

목차

1. Introduction

2. Theoretical Approach

3. Experimental Procedure

4. Results and Discussion

5. Conclusions

References

키워드

Tunnel fire Velocity attenuation Smoke layer Semi-empirical model Tranquil flow region