In this paper, results of numerical simulations of rich spray flame propagation in a two-dimensional channel are presented for the first time. The study deals with a constant density model thereby eliminating the Darrieus-Landau instability. Attention is focused on (i) the stability of planar spray flames and comparing the predicted results with those of a previously reported linear stability analysis, and (ii) nonlinear development of cellular spray flame fronts that were reported in independent experimental studies. The way in which the spray of droplets impacts on the average speed of flame propagation is also discussed. In general, the numerical simulations qualitatively replicate both experimental and theoretical results.