变循环发动机外涵流量随工作模态转换会发生大幅变化，相应的宽范围内外涵道掺混流动对于形成均匀的燃油空间分布带来了挑战。对变循环发动机在不同模态下加力燃烧室的燃油分布特性进行了数值仿真，探究了宽范围外涵气流变化对燃油分布的影响规律，并形成了面向多模态加力燃烧室的燃油喷注优化策略。研究结果表明，加力燃烧室混合气体沿径向的速度分量和波瓣混合器诱导产生的流向涡分别是影响燃油径向/周向扩散的关键因素。小涵道比模态下，内涵主导的高温高速流动使得不同区域的燃油扩散速度相对一致；而大涵道比模态下气体径向速度和流向涡分布规律发生明显改变，导致不同区域的燃油扩散速度表现出明显的差异性，影响到燃油分布的均匀程度。在此基础上，提出了适度增加中间位置喷嘴燃油流量的优化策略，结果表明，相比平均分配燃油流量的供应方案，优化后的燃油分布均匀程度最高将提升33.04%。

The flow rate of the extra-cylinder of the variable-cycle engine will change greatly with the transition of the working mode， and the corresponding internal/external contour blending flow brings challenges to the fuel injection scheme of the afterburner. In order to solve this problem， this paper numerically simulates the fuel distribution characteristics of afterburner in variable cycle engine under different modes， explores the influence of wide-range airflow change on fuel distribution， and forms a fuel injection optimization strategy for multi-modal afterburner. The results show that the velocity component of the afterburner mixture along the radial direction and the flow vortex induced by the lobe mixer are the key factors affecting the radial/circumferential diffusion of the fuel， respectively. In the small bypass ratio mode， the connotation-dominated high-temperature and high-speed flow makes the fuel diffusion velocity relatively consistent in a wide range. However， the radial velocity and vortex distribution of the gas change significantly in the large bypass ratio mode， resulting in obvious differences in the fuel diffusion velocity in different regions， which affects the uniformity of fuel distribution. On this basis， an optimization strategy is proposed to moderately increase the fuel flow rate of the nozzle at the middle position， and the results show that the uniformity of fuel distribution will be increased by up to 33.04%.