Tünellerde n-heptan ve etanol havuz yangınlarının yanma özellikleri üzerine deneysel bir çalışma.

The road and railway tunnel disasters in recent decades drew the attention of fire safety engineers. The effects of mechanical ventilation, tunnel geometry, physical and chemical properties of fuel on fire characteristics such as heat release rate, smoke temperature distributions along the tunnel and burning rate are experimentally examined on full scaled, large scaled and reduced scaled tunnel models. Although there are many studies on the effects of conventional fuels like gasoline and diesel, the blended fuels and radiative effects of fire are barely addressed in tunnel fire scenarios. In this study, heptane pool fires and 10 %, 20 % and 30 % volumetric fractions of ethanol blended heptane pool fires are studied with square and rectangular pan geometries under 0.5 m/s to 2.5 m/s ventilation conditions with 0.5 m/s incremental intervals in a reduced scale tunnel model based on the Froude number scaling. Two separate experimental matrices are prepared with one variable at a time approach. The fuel mass, temperature distribution, O2, CO2 and CO gas concentration are measured and are compared to observe the effect of changing parameters. The interior wall surfaces of tunnel are covered with high reflecting material for particular ethanol pool fires. The radiative heat flux of fire, the back radiation of walls and combustion gases are respectively measured through a series of experiments.M.S. - Master of Scienc

Tünel Yangını Sırasında Taşıt Blokajının Farklı Havalandırma Hızlarında Yangın Yüküne Etkisi

Projede amaçlanan tünellerde meydana gelen yangın kazalarını küçük ebatlarda modellendirerek yanma ile açığa çıkan ısı salınımı ve tünel içinde oluşan sıcaklık dağılımının farklı parametrelerle değişimlerini incelemektir. Farklı havalandırma hızları ve ışınım değerleri değişen malzemelerin sıcaklık dağılımı ve ısı salınım hızına etkilerini araştırmak gelecekte tasarlanacak tünellerin güvenliğini arttırmada faydalı olabilecek bir çalışma olarak düşünülmektedir. Yanma esnasında ortam sıcaklığını düşürebilecek veya yanma ürünlerinin konsantrasyonlarında düşüş sağlayabilecek bir değişken tünellerin geliştirilmesinde önemli rol oynayacak çalışmalara destek olabilecek nitelikte bir çalışma olabilir

AN EXPERIMENTAL STUDY ON THE CHARACTERISTICS OFn HEPTANE ETHANOL MIXTURE POOL FIRE IN A REDUCED SCALE TUNNEL

Fire accidents in recent decades have drawn attention to safety issues associated with the design, construction and maintenance of tunnels. A reduced scale tunnel model constructed based on Froude scaling technique is used in the current work. Mixtures of n-heptane and ethanol are burned with ethanol volumetric fraction up to 30 percent and the longitudinal ventilation velocity varying from 0.5 to 2.5 m/s. The burning rates of the pool fires are measured using a precision load cell. The heat release rates of the fires are calculated according to oxygen calorimetry method and the temperature distributions inside the tunnel are also measured. Results of the experiments show that the ventilation velocity variation has a significant effect on the pool fire burning rate, smoke temperature and the critical ventilation velocity. With increased oxygen depletion in case of increased ethanol content of blended pool fires, the quasi-steady heat release rate values tend to increase as well as the ceiling temperatures while the combustion duration decreases