Experimental study on thermal stratification characteristics in tunnel fires under the effect of canyon cross wind

Release time:2022-02-25

Impact Factor:4.082

DOI number:10.1016/j.jweia.2021.104756

Journal:JOURNAL OF WIND ENGINEERING AND INDUSTRIAL AERODYNAMICS

Key Words:Tunnel fireCanyon cross windReduced-scale experimentThermal stratificationSmoke layer thickness

Abstract:In order to investigate the thermal stratification characteristics induced by pool fire and canyon cross wind, a set of tests were carried out in a 1:20 model tunnel. Experimental parameters were the canyon wind speed, longitudinal fire location and fire size. Results show that the dimensionless smoke layer thickness h* (the ratio of smoke layer thickness to hydraulic diameter) downstream the fire generally increases with increasing canyon wind speed until reaching the maximum value, and h* of a smaller-scale fire is slightly greater than that of a larger-scale fire at most canyon wind speeds. However, h* value upstream the fire is almost between 0.2 and 0.3 (h* = 0 is not considered). The smoke stratification downstream the fire gradually worsens with increasing canyon wind speed and decreasing distance between the fire source and the upstream portal D-f in the cases of 0.194 <= D-f* < 1 (D-f* represents the ratio of D-f to the tunnel length), while the smoke stratification upstream the fire is always obvious unless there is no smoke. As D-f increases, the critical Froude number for judging the smoke stratification status decreases first for 0 <= D-f* < 0.028 and then increases for 0.028 <= D-f* < 0.306, and tends to be a constant value for 0.306 <= D-f* < 1.

Indexed by:Journal paper

Correspondence Author:Yang, LL; Fan, CAG*; Luan, DA; Ouyang, RC; Tao, HW; Xu, ZS; Wang, FY*

Discipline:Engineering

First-Level Discipline:Power Engineering and Engineering Thermal Physics

Document Type:J

Volume:218

Page Number:104756

ISSN No.:0167-6105

Translation or Not:no

Date of Publication:2021-10-08

Included Journals:SCI