CFD Analysis of a Rail Way Tunnel Ventilation
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Date
2016-09
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AAU
Abstract
The aim of a tunnel ventilation system is to reach the major safety levels as possible both in fire
and service situations. In service situation the system has to guarantee that the atmosphere of the
tunnel assembles a suitable condition of comfort and safety for the users; assuring the dilution of
the pollutants from the vehicles to admissible limits, and allowing a suitable reaction capacity in
case of a quick demand of flow. On the other hand, in case of fire the aims would be to control
the smoke layer as far from the users as possible, to avoid the spreading of the incident to zones
not implied in the fire and to support in rescue tasks.
ANSYS FLUENT is Computational Fluid Dynamics (CFD) software that allows users to
simulate flow problems of ranging complexity. It contains broad physical modeling capabilities
needed to model flow, turbulence, heat transfer, and reactions over objects designed by the user.
In this thesis the objective of the study is to analyze the rail way tunnel ventilation system using
CFD software to create comfort ventilation system in the tunnel. The comfort ventilation concept
refers to the situation when air quality within the tunnel is reduced due to presence of polluted
air in the tunnel. Based on the conditions on, Mekele tunnel numerical analysis of air flow field
is carried out by the finite element software—CFD and k-ɛ turbulence model to show the volume
flow rate of the expelled air out of the tunnel by using jet fans in this paper.The result shows that the required amount of air is removed by using a series arrangement of jet
fans to create the comfort ventilation system in the tunnel.
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Keywords
Rail Way Tunnel, Tunnel Ventilation, CFD