FLAME AND DROPLET INTERACTION EFFECTS DURING DROPLET-STREAM COMBUSTION AT ZERO REYNOLDS-NUMBER

This work presents a numerical analysis of the quasi-steady combustion of an infinite stream of droplets in the limit of infinite Damkohler number and stagnant ambient conditions. The small and large length-sca le phenomena associated with the process are addressed by splitting th e physical domain into near- and far-field subdomains. Within the inne r subdomain, validated expressions are used during the grid generation procedure, allowing the development of appropriate finite-difference expressions and control of the distribution of points. Analytical tran sformations are developed and applied to the outer subdomain coordinat e system in order to match the inner and outer grids along the domain interface and to properly address the outflow boundary conditions usin g a regularly spaced grid. A system of transformed governing equations is obtained and discretized into a coupled system of algebraic equati ons, which are solved by standard scientific subroutines, incorporatin g automatic control of error. The developed transformations are invert ed and the solutions within the physical domain are obtained. Interdro plet interaction effects are presented in terms of droplet mass vapori zation rate, droplet lifetime, and flame-sheet shape and position for different droplet spacings and fuels. The results indicate interaction effects present over a broad range of interdroplet spacings and are c ompared with theoretical and experimental ones available in the litera ture.