Flame spread in laminar mixing layers: the triple flame

In the present paper we investígate flame spread in laminar mixing layers both experimentally and numerically. First, a burner has been designed and built such that stationary triple ñames can be stabilised in a coflowing stream with well defined linear concentration gradients and well defined uniform flow velocity at the inlet to the combustión chamber. The burner itself as well as first experimental results obtained with it are presented. Second, a theoretical model is formulated for analysis of triple flames in a strained mixing laycr generated by directing a fuel stream and an oxidizer stream towards each other. Here attention is focused on the stagnation región where by means of a similarity formulation the three-dimensional flow can be described by only two spatial coordinates. To solve the governing equations for the limiting case in which a thermal-diffusional model results, a numerical solution procedure based on self-adaptive mesh refinement is developed. For the thermal-diffusional model, the structure of the triple flame and its propagation velocity are obtained by solving numerically the governing similarity equations for a wide range of strain rates

Immobilized Candida antarctica Lipase Catalyzed Transesterification of Croton megalocarpus Seed Oil for Biodiesel Production

Methanolic transesterification of Croton megalocarpus seed oil to produce biodiesel was investigated using Immobilized Candida antarctica lipase as a catalyst. The reactions were optimized by varying the temperature, amount of methanol and the weight of lipase. The transesterification process yielded 98.71 % biodiesel conversion at optimal conditions of 30 % enzyme (m/m), 50 0C reaction temperature and oil to alcohol molar ratio of 1:4. Biodiesel from this process had a remarkably high acid value. All the other fuel properties measured were within the range stipulated in the American Society for Testing and Materials (ASTM) and International Standards Organization (ISO) standards.   Keywords: Biodiesel, Croton megalocarpus, Transesterification, lipas