Measurements of pressure and flame speed during explosions of CH4/O2/N2/CO2 mixtures. (November 2016)

• Record Type: Journal Article
• Authors: Cammarota, F.; Di Sarli, V.; Salzano, E.; Di Benedetto, A.
• Is Part Of: Journal of loss prevention in the process industries. Volume 44(2016:Nov.)
• Page Start: 771
• Page End: 774
• Publication Date: 2016-11
• Subjects: Explosion -- Deflagration -- Detonation -- combustion-induced Rapid Phase Transition -- Flame speed -- Oxy-fuel combustion; Chemical industries -- Safety measures -- Periodicals; 660.2804
• DOI: 10.1016/j.jlp.2016.06.005
• Languages: English
• ISSNs: 0950-4230

Abstract

Abstract: The explosion behavior of CH4 /O2 /N2 /CO2 mixtures was investigated by coupling spatial and temporal measurements of pressure with the temporal signals of photodiodes placed along the vessel length. The O2 /CH4 ratio was always stoichiometric, the oxygen air enrichment factor, E = O2 /(O2 + N2 ), was set to 0.8, and the dilution (CO2 %v/v) was changed from 30 to 40%v/v. The signals of the photodiodes reveal that the flame speed varies from 7 to 100 m/s and, thus, the burning velocity is within the range of 0.7–10 m/s. The pressure signals exhibit oscillations and, at the lowest CO2 content (30%v/v), a pressure peak exceeding the adiabatic value is found. The pressure signal and the flame speed values definitely demonstrate that the over-adiabatic peak cannot be attributed to detonation or DDT, but it can be related to the coupling between deflagration and rapid phase transition of water (combustion-induced Rapid Phase Transition, c-RPT). Highlights: Explosion behavior of CH4 /O2 /N2 /CO2 mixtures investigated. Oxygen air enrichment factor, E = O2 /(O2 + N2 ), set to 0.8 CO2 %v/v varied from 30 to 40%v/v. Flame speed measured by using photodiodes. Over-adiabatic peaks can only be attributed to cRPT.