title: Burning velocity measurements of nitrogen-containing compounds.
abstract: Burning velocity measurements of nitrogen-containing compounds, i.e., ammonia (NH3), methylamine (CH3NH2), ethylamine (C2H5NH2), and propylamine (C3H7NH2), were carried out to assess the flammability of potential natural refrigerants. The spherical-vessel (SV) method was used to measure the burning velocity over a wide range of sample and air concentrations. In addition, flame propagation was directly observed by the schlieren photography method, which showed that the spherical flame model was applicable to flames with a burning velocity higher than approximately 5 cm s(-1). For CH3NH2, the nozzle burner method was also used to confirm the validity of the results obtained by closed vessel methods. We obtained maximum burning velocities (Su0,max) of 7.2, 24.7, 26.9, and 28.3 cm s(-1) for NH3, CH3NH2, C2H5NH2, and C3H7NH2, respectively. It was noted that the burning velocities of NH3 and CH3NH2 were as high as those of the typical hydrofluorocarbon refrigerants difluoromethane (HFC-32, Su0,max=6.7 cm s(-1)) and 1,1-difluoroethane (HFC-152a, Su0,max=23.6 cm s(-1)), respectively. The burning velocities were compared with those of the parent alkanes, and it was found that introducing an NH2 group into hydrocarbon molecules decreases their burning velocity.
authors.affiliation: National Institute of Advanced Industrial Science and Technology (AIST), Central 5, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan. k.takizawa@aist.go.jp
authors.forename: Kenji
authors.initials: K
authors.lastname: Takizawa
authors.forename: Akifumi
authors.initials: A
authors.lastname: Takahashi
authors.forename: Kazuaki
authors.initials: K
authors.lastname: Tokuhashi
authors.forename: Shigeo
authors.initials: S
authors.lastname: Kondo
authors.forename: Akira
authors.initials: A
authors.lastname: Sekiya
mesh_terms: D000588:Amines / Q000737:chemistry*; D000641:Ammonia / Q000737:chemistry*; D005390:Fires; D012034:Refrigeration
chemical_list: D000588:Amines; D000641:Ammonia