Experimental study on heat transfer of tunnel fire under the influence of longitudinal ventilation and water mist system

2020 ◽  
Author(s):  
Yuchun Zhang ◽  
Kejian Zhang ◽  
Longfei Chen ◽  
Pengfei Mao
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Water Mist ◽  
Tunnel Fire ◽  
Longitudinal Ventilation

scholarly journals Numerical Simulations on the Extinguishing Effect of Water Mist System with Different Parameters of Longitudinal Ventilation in Curve Tunnel Fire

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Zhizhong Liu ◽  
Chen Chen ◽  
Mu Liu ◽  
Song Wang ◽  
Yuzhu Liu
Keyword(s):  
Operation Time ◽  
Water Mist ◽  
Wall Friction ◽  
Thermal Pressure ◽  
Smoke Flow ◽  
Effect Of Water ◽  
Tunnel Fire ◽  
Longitudinal Ventilation ◽  
Fire Extinguishing ◽  
Ventilation Velocity

Once a fire occurs in a long curve tunnel, the mixing of hot smoke flow and cold air leads to turbulence due to the curvature’s impact. This phenomenon results in a greater thermal pressure difference at the fire source and a substantially greater temperature field than in the straight tunnel. The longitudinal air flowing along the wall loses a lot of velocity in the curve tunnel due to the massive wall friction. Under the same fire extinguishing conditions, the curve tunnel and straight tunnel have different requirements for longitudinal ventilation. Factors such as tunnel curvature, longitudinal ventilation operation time, and ventilation velocity were all evaluated in order to investigate the influence of longitudinal ventilation parameters on the fire extinguishing effect of water mist in the curve tunnel. The fire extinguishing effect of water mist coupling with longitudinal ventilation in the curve tunnel is studied by numerical simulation, and the recommended values of ventilation operation time and ventilation velocity in the curve tunnel with the participation of the water mist system are given. The results show that (1) the fire extinguishing effect of water mist decreases with the increase of curvature under longitudinal ventilation and (2) fire prevention effect is best when water mist and longitudinal ventilation are used in the curved tunnel, and the ventilation velocity should be greater than 2 m/s.

scholarly journals Experimental Study on Suppression of n-Heptane Pool Fire with Water Mist under Longitudinal Ventilation in Long and Narrow Spaces

2013 ◽  
Vol 62 ◽  
pp. 946-953 ◽  
Author(s):  
Quanwei Li ◽  
Pin Zhang ◽  
Song Guo ◽  
Renming Pan ◽  
Jun Qin ◽  
...  
Keyword(s):  
Experimental Study ◽  
Water Mist ◽  
Pool Fire ◽  
Longitudinal Ventilation

Experimental study of water mist fire suppression in tunnels under longitudinal ventilation

2009 ◽  
Vol 44 (3) ◽  
pp. 446-455 ◽  
Author(s):  
Lvyi Chen ◽  
Wei Zhu ◽  
Xin Cai ◽  
Liwei Pan ◽  
Guangxuan Liao
Keyword(s):  
Experimental Study ◽  
Fire Suppression ◽  
Water Mist ◽  
Longitudinal Ventilation

Experimental study of thermohydraulic characteristics and irreversibility analysis of novel axial corrugated tube with spring tape inserts

2020 ◽  
Vol 92 (3) ◽  
pp. 30901
Author(s):  
Suvanjan Bhattacharyya ◽  
Debraj Sarkar ◽  
Ulavathi Shettar Mahabaleshwar ◽  
Manoj K. Soni ◽  
M. Mohanraj
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Thermal Performance ◽  
Working Fluid ◽  
The Novel ◽  
Heat Exchanger Tube ◽  
Heat Transfer Augmentation ◽  
Corrugated Tube ◽  
The Impact ◽  
Exchanger Tube

The current study experimentally investigates the heat transfer augmentation on the novel axial corrugated heat exchanger tube in which the spring tape is introduced. Air (Pr = 0.707) is used as a working fluid. In order to augment the thermohydraulic performance, a corrugated tube with inserts is offered. The experimental study is further extended by varying the important parameters like spring ratio (y = 1.5, 2.0, 2.5) and Reynolds number (Re = 10 000–52 000). The angular pitch between the two neighboring corrugations and the angle of the corrugation is kept constant through the experiments at β = 1200 and α = 600 respectively, while two different corrugations heights (h) are analyzed. While increasing the corrugation height and decreasing the spring ratio, the impact of the swirling effect improves the thermal performance of the system. The maximum thermal performance is obtained when the corrugation height is h = 0.2 and spring ratio y = 1.5. Eventually, correlations for predicting friction factor (f) and Nusselt number (Nu) are developed.

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