A fuel regression rate simulation model of solid fuel ramjet was constructed based on the conservation laws. With two-dimensional axisymmetric model and two-equation chemical reaction model

numerical simulations of HTPB (hydroxyl terminated polybutadiene) solid fuel ramjet flow field were performed and the influences of inlet air conditions on flow field distributions and fuel regression rate characteristics were analyzed. Results show that combustion flame layer is developed between the central oxygen region and solid fuel wall. The thickness of the combustion layer decreases and shifts toward the fuel wall with the increase of inlet air mass flow rate and total temperature. With the increasing axial location

the fuel regression rate increases sharply first and then increases slowly. At last

the fuel regression rate decreases quickly near the aft-mixing chamber. This trend matchs well with the experimental results of the reference. The average fuel regression rate increases with the increase of inlet air total temperature and air mass flux. An average fuel regression rate formula is fitted with the simulation results.