The numerical study is executed for polymethylmethacrylate ignition (typical model fuel for hybridrocket motors) by single particles in the shape of parallelepiped, polyhedron, and disk. The initial temperature ofheat source is varied in the range of 950-1150 K, the size of hot particle is varied in the range of 2-6 mm. It isfound that the change of these parameters significantly affect on the basic characteristics of the process -ignition delay time at conditions close to the critical ignition conditions. For considered particles with differentshapes ignition delay time are arranged in ascending order: parallelepiped, polyhedron, and disk. Three ignitionmode of polymer is studied. They are characterized by an initial temperature of the heat source, the ignitiondelay time and the position of the ignition zone in the vicinity of a hot particle. It is shown that taking intoaccount the dependence of thermophysical characteristics on the temperature of polymer increase the ignition delay time due to the increasing of accumulated energy by near-surface layer
