საავტომობილო გვირაბების სხვადასხვა მასშტაბის ფიზიკურ მოდელებზე დაგეგმილი გვაქვს ვენტილაციის მნიშვნელოვანი ტექნოლოგიური პარამეტრების შესწავლა ხანძრის პირობებში. მოდელირება შესრულდება გ. წულუკიძის სამთო ინსტიტუტსა და საქართველოს ტექნიკურ უნივერსიტეტში. აღნიშნული მოდელები შეავსებენ ერთმანეთს და დაგვეხმარებიან კრიტიკული სიჩქარის, უკუდინების სიგრძისა და გრადიენტ-ფაქტორის რიცხვითი სიდიდეების ცვალებადობათა კანონზომიერებების დადგენაში. ფიზიკური მოდელირებით მიღებული შედეგები შედარდება სრულმასშტაბიანი თანამედროვე საინჟინრო პროგრამული პაკეტების Pyrosim და Fluent-ის გამოყენებით მიღებულ რიცხვითი მოდელირების შედეგებს იმ მიზნით, რომ ახალი შედეგების გამოყენება შესაძლებელი გახდეს კონკრეტული გვირაბის გეომეტრიის, ადგილმდებარეობისა და ტოპოლოგიისათვის.

The paper considers various scenarios of fire development in road tunnels. The dynamics of combustion products propagation is studied by taking into account the fire strength, tunnel geometry and layout, and aerodynamics of the ventilation flow. The impact of strong fires on the sustainability and proper operation of ventilation systems is demonstrated, and different types of numerical models are considered with the FDS software environment. Theoretical and numerical experiments have demonstrated that strong fires in tunnels can induce dynamic pressures greater than the static pressures of the tunnel fans. The latter can change the direction of movement of ventilation flows in the tunnels with an inclination of 3% or more when the seat of fire is at a hypsometrical height lower than the air supply portal, thus drastically impairing the self-evacuation capability of people in the disaster zone. It was demonstrated that one of the most reliable ways to save lives in case of fire is to limit the spread of flue gases to prolong the time for evacuation. The paper proposes a transformable flexible system to save lives, which artificially increases the aerodynamic resistance of tunnels to prevent the propagation of harmful combustion products on the people’s evacuation route. By considering the fire development scenarios in horizontal and inclined tunnels, the dynamics of the spread of the fire damaging factors when ventilation system is no longer operable and the only solution is the use of the flexible system is examined. The results of modeling evidence that by closing 50% of the tunnel cross-section with a flexible system it is possible to obtain important positive results in reducing the spread of combustion products and saving lives. The use of the proposed system reduces the intensity of the spread of fire hazards and will definitely help the people in the disaster zone. The analysis carried out clearly shows its necessity and that the comprehensive study of fires and generalization of study results will be useful in adequate planning and implementing future measures to prevent and reduce their harmful effects. Following the above-mentioned, a detailed description, analysis and development of a clear algorithm of action of fire cases, and communicating the results to rescuers, tunnel service personnel and the general public are needed.

The results of numerical modeling in longitudinal ventilated sloping road tunnels are given. The slope of the tunnels varies in the range of 0-6%. The geometry of the tunnel is as follows: length: 100 m; width: 8 m; height: 6 m; area of the seat of fire: 16 m2. The seat of fire sized: 2.75x5.8x1.5 m is in the central part of the tunnel. The scenarios of development of 5, 10, 20, 30, 50 MW fires are studied in the case of positive and negative directional ventilation flows. The time of modelling was 120 seconds. The numerical problems were modelled with a volumetric grid method. The grid cell dimensions were: 0.5*0.5*0.5 m. Virtual point and volumetric measuring equipment was used to record the modeling results. The modelling used 4 groups of measuring devices that measured and recorded air velocity, temperature, and air and smoke densities. The paper discusses cases of algebraically summarizing the ventilation and fire-induced flows. Based on the results of numerical modeling, we can point out that the widely accepted indices of critical velocity and back-layering length in inclined road tunnels often give erroneous results. Therefore, in strategies for emergency ventilation, indicators such are critical velocity and back-separation should be used with caution.