About AAQR

Aims and Scope

Articles online
For contributors
Call for Papers
Guideline for the
Special Issue Proposal
Subscription
Information

Advertising

Contact Us
 
Search for  in   Search  Advanced search  

 

Volume 6, No. 3, September 2006, Pages 231-246 PDF(520 KB)  
doi: null   

Numerical Investigation of Flow and Dust Concentration Distributions in the Work Area of a Mountain Tunnel Currently under Construction

Chikao Kanaoka1, Masami Furuuchi2, Thosihiko Myojo3, Jun-ichi Inaba2, Kazuyo Ohmata2

1 Ishikawa National College of Technology, Kitacyujo, Tsubata, Kahoku-gun, Ishikawa, 929-0392, Japan
2 Graduate School of Natural Science and Technology, Kanazawa University, Kakuma-machi, Kanazawa, 920-1192, Japan
3 Division of Human Engineering, National Institute of Industrial Health, Nagao 6-21-1, Tama-ku, Kawasaki, 214-8585, Japan

 

Abstract

 

Flow patterns, dust concentration profile, and particle motion in a mountain tunnel under construction were calculated numerically for a full-scale tunnel to evaluate the effectiveness of the planned ventilation system. The influence of ventilation air flow rate, the configuration of air tubes, and an obstacle near the working face were investigated. The trajectories of different size particles were calculated at different wall conditions for deposition. A vortex flow was found to form between the air inlet and the working face for all ventilation types examined. The average dust concentration at a height of 1.5 m, corresponding to the average breathing height of a worker, did not consistently decrease with an increased air flow rate in an injection-suction type system. An optimal air flow rate for minimizing the dust concentration may exist. A vortex flow developed around an obstacle near the working face, leading to an increase in dust concentration between the obstacle and the working face. The concentration of dust near the working face was extremely high and was too spatially variable to be accurately described by the average dust concentration in the area between the working face and the air inlet. The fraction of particles removed through the air outlet was dependent on the ventilation pattern, and also decreased with increasing particle size due to immediate deposition of coarse particles on the tunnel floor.

 

 

Keywords: Numerical analysis; Ventilation; Dust concentration; Particle motion.

 

 

Copyright © 2009-2014 AAQR All right reserved.