Nakahara M.,Ehime Univeisiti. |
Onisi-Il Y.,Ehime Univeisiti. |
Nishihara T.,Ehime Univeisiti. |
Abe F.,Ehime Univeisiti.
Nihon Kikai Gakkai Ronbunshu, B Hen/Transactions of the Japan Society of Mechanical Engineers, Part B | Year: 2012
This Stlldy Is performed to experimentally examine the fundamental burning velocity characteristics of meso-scale spherical laminar flames in the range of flame radius r f approximately from I to 5 mm for hydrogen-oxygen mixtures diluted with Ar. CO 2 or N 2. in order to make clear an influence of dilution gas on burning velocities of meso-scale flames and a method for improving combustion of niicro-mcso scale flames. Macro-scale laminar flames w ith r f>7 mm are also examined for comparison. The mixtures have nearly the same laminar burning velocity for unstretched flames and different equivalence ratios θ(=O.5̃4).9). The radius and the burning velocity of ineso-scale flames are obtained by using sequential schlicrcn images recorded under appropriate ignition conditions It is found iiiat the burning velocities of meso-scale flames for CO 2 diluted mixtures (θ=0.5̃0.9) have a tendency to decrease with increasing r f, and approach those of macro-scale flames. Such a trend, however, can not be seen for Ar- as well as N2- diluted mixtures of hydrogen and oxygen with 0.7 and 0.9. whose burning velocity of meso-scale flames can not be explained based on that of macro-scale Ilamnes. This suggests that mnmcro-meso scale flames have the optimum site amid Karlovitz number to improve the burning velocity, depending on dilution gas types in addition to and fuel types. © 2012 The Japan Society of Mechanical Engineers.