受固体推进剂能量水平限制，固体火箭发动机的比冲相对较低，而注氦型固-气混合火箭发动机能通过向固体发动机内注入分子量低、膨胀能力强的氦气可有效提高发动机比冲。为进一步提高注氦型固-气混合火箭发动机性能，对采用微孔阵列注氦的固-气混合火箭发动机进行数值模拟，对比分析了微孔尺度对发动机性能的影响。数值模拟结果表明，发动机比冲随着氦气注入比例（氦气注入流量与燃气流量的比值）的变化呈现出抛物线趋势，在氦气注入比例为1:4时达到峰值。较小的微孔尺度下，发动机可以获得更高的比冲增益，比冲增益最高可达5.77%。氦气质量分数低的混合气体对发动机比冲提供正增益，而氦气质量分数高的混合气体由于总温较低、膨胀能力弱而导致比冲负增益，因此发动机比冲取决于高、低氦气质量分数混合气体的共同作用。发动机推力随氦气注入比例增加而不断增加，通过改变氦气注入比例从0到2:1，微孔直径2 mm的发动机可实现100%-313%的最大推力调节范围。氦气的注入大幅减低了燃气的出口温度，喷管出口均温最高降低了1600 K。因此，注氦型固-气混合发动机能有效降低发动机尾喷口的羽流温度，抑制羽流红外辐射特征，获得较好的红外隐身效果。

Limited by the energy level of solid propellant, the specific impulse of solid rocket motor is relatively low. The helium-injected solid-gas hybrid rocket motor can effectively improve the specific impulse of solid rocket motor by injecting helium with low molecular weight and strong expansion capacity into the rocket motor. In order to improve the perfor-mance of the helium-injected solid-gas hybrid rocket motor, the effect of micro-hole arrays on the performance of the helium-injected solid-gas hybrid rocket motor is investigated. Results show that the specific impulse of the motor pre-sents a parabolic trend with the variation of helium injection ratio (mass flow ratio of helium to combustion gas), and the peak value is reached when the helium injection ratio is 1:4. The motor can obtain a maximum specific impulse gain of 5.77% with the micro-hole diameter of 2 mm. The mixed gas with low helium mass fraction provides positive gain to the specific impulse of the motor, while the mixed gas with high helium mass fraction causes negative gain due to the low total temperature and weak expansion capacity. Therefore, the specific impulse of the motor depends on the combination of the mixed gas with high and low helium mass fraction. Furthermore, motor thrust increases with the increase of helium injection ratio. By changing the helium injection ratio from 0 to 2:1, a motor can achieve a maximum thrust adjustment range of 100%-313%. The injection of helium greatly reduces the nozzle outlet temperature by up to 1600 K. Therefore, the helium-injected solid-gas hybrid motor can effectively reduce the plume temperature of the rocket motor, suppress the infrared radiation characteristics, and obtain a better infrared stealth effect.