Abstract: To accurately predict the combustion characteristic of polyethylene in solid fuel ramjet,the viscosity and thermal conductivity coefficients of C₂H₄, CO, CO₂, H₂O, O_2and N_2were estimated at different temperature. And mass, momentum and energy sources were added using UDF. The results show that the trend of regression rate against the change of the total temperature or mass flow rate of air is agreed well with existing experiments. The maximum errors of mean regression rates and aft-mixing combustion chamber temperatures are 11.3% and 5.2%,respectively. And the trend of aft-mixing combustion chamber temperature is opposite with the mass flow rate of air. When the total temperature of air increases or the mass flux decreases, the length of aft-mixing combustion chamber needs to be longer to fully burn the fuel.With geometric similarity, when other operation conditions are the same, the heat flux from flow field to surface of propellant and regression rate are greater in smaller size SFRJ. 

Key words: Solid fuel ramjet;Combustion property; Polyethylene;Regression rate;Size effect

摘要： 为准确模拟聚乙烯在固体燃料冲压发动机中的燃烧状态,估算了乙烯-空气两步反应中,相关组分的粘性、导热系数随温度的变化,并进行多项式拟合；同时使用UDF进行质量、动量、能量添加。数值计算的结果表明:燃面退移速率的计算误差不超过11.3%,其变化规律与已有实验相同；补燃室温度的误差不大于5.2%；补燃室温度随来流空气质量流率的增大而减小；高来流空气总温或低来流空气质量流率的工况下,燃料充分燃烧所需的补燃室更长；几何相似,其它条件相同时,小尺寸发动机内流场传向燃料表面的热流密度更大,燃面退移速率更高。 

关键词: 固体燃料冲压发动机;燃烧特性;聚乙烯;燃面退移速率;尺寸效应 