This study concerns two-phase flame propagating through a 2D-lattice of alkane droplets surrounded by a gaseous pre-mixture of alkane air. Spray flame speed is numerically measured for spray compositions. To study such very heterogeneous media, the retained chemical scheme is a global irreversible one step reaction governed by Arrhenius law, with a modified heat of reaction depending on local equivalence ratio. Studied sprays are globally rich. For global equivalence ratio greater than 1.4, and lattice spacing large enough, the presence of droplets promotes combustion (in comparison with single phase flame dynamics). When the vapor pressure becomes important, droplets do not participate to combustion. These numerical results are in qualitative good agreement with recent experimental contributions on spray combustion. Nomenclature () ϕ F heat of reaction depending on equivalence ratio i Le Lewis number of species i in the mixture L x , L Y longitudinal and transversal box lengths P e s spray Peclet number L U adiabatic speed for single-phase premixed flame U L * adiabatic flame speed for stoichiometric gaseous mixture U s spray-flame speed s vlattice spacing b T adiabatic flame temperature for stoichiometric gaseous mixture Z mixture fraction e Z Zeldovich number for stoichiometric gaseous mixture ϕ u local equivalence ratio L ϕ liquid equivalence ratio of the fresh spray (overall liquid loading) G ϕ gaseous equivalence ratio of the fresh spray T ϕ overall equivalence ratio of the fresh spray θ reduced temperature i Ψ reduced mass fraction of specie i