Research Information System
Thesis Type: Postgraduate
Institution Of The Thesis: Gazi University, Fen Bilimleri Enstitüsü, Turkey
Approval Date: 2022
Thesis Language: Turkish
Student: Betül DEMİRCİ
Supervisor: Nureddin Dinler
Open Archive Collection: AVESIS Open Access Collection
Abstract:
The concept of the tunnel, which is one of the important elements of road and rail transport, is frequently examined by researchers. While examining the tunnels that facilitate transportation, all kinds of scenarios that can be experienced in them are handled with the help of both experimental and computer programs. In this study, analytical calculations and numerical analysis of a 1.5 km long curved tunnel designed according to the technical specifications prepared by the General Directorate of Highways were made. While analytical solutions were made with the equations prepared by PIARC, numerical solutions were made with the help of Ansys/FLUENT which is a computational fluid dynamics solver. The main purpose of this thesis is to investigate the effects of the fire scenario that occurs in different locations of a curved tunnel ventilated using a conventional jet fan. Features such as turbulence model selection, number of jet fans, and ventilation method were investigated with a large literature study without CFD analysis. Analyses were carried out through the obtained data. The results of the fire analyses made according to different locations are shown with the contours and graphics provided by the FLUENT program. It was observed that the temperature distribution in the tunnel was lower in cases where the fire source approached the exit portal. In the fire source close to the entrance portal, since the smoke is not evacuated quickly, the heat inside cannot be discharged immediately and an increase in the temperature distribution in the tunnel occurs. The air flow emanating from the jet fans adheres to the concave wall with the Coanda effect and causes the high-temperature smoke to be directed towards the convex wall. For this reason, it is seen that the temperature values in the convex part of the tunnel are higher than the temperature values in the concave wall part in the areas close to the fire area. In addition, it has been observed that the velocity of the gases expanding with the effect of increasing temperature is higher in places close to the fire area.
| Key Words : Tunnel fire, ventilation system, Froude number, curvature, scaled model, jet fans |