INTERACTION OF 2 BURNING FUEL DROPLETS OF ARBITRARY SIZE

The combustion of two interacting droplets of arbitrary size was analyzed by solving Laplace's equation in bispherical coordinates, with the conjecture that multiplication by l_n(1 + B) converts the diffusion rate in the absence of a flame to the evaporation rate of a burning droplet. Closed-form solutions were obtained both for the burning rate of each droplet and for the shape of the flame. The burning rate of each droplet was found to be smaller than that of an isolated droplet of the same size. The reduction was greatest when the droplets were touching, and was relatively larger for the smaller droplet. Two simple functions, one for the larger droplet and one for the smaller, were found to give good approximations to the burning rate of touching droplets. Free-fall experiments were performed to check the theory. The results available so far have provided qualitative support for the mathematical model in that observed flames of some pairs of burning droplets strongly resemble the calculated flame shape. © 1979 American Institute of Aeronautics and Astronautics, Inc., All rights reserved.