We congratulate Li Qiang for the journal paper acceptance by Combustion Theory and Modelling, entitled “On the evolution of fuel droplet evaporation zone and its interaction with flame front in ignition of spray flames”. In this work, a theoretical model is developed to study the interactions between the flame front and fuel droplet evaporation zone in flame spark ignition stage, which leads to the phenomenon of “homogeneous and heterogeneous flames”. This general theory can be used for explaining some peculiar spray flame dynamics observed from experiments or detailed simulations. [30/10/2021]