论文部分内容阅读
含能聚合物是激光烧蚀微推进中一类重要的推进剂,聚叠氮缩水甘油醚(GAP)是其中的典型代表。为了研究含能聚合物固体薄膜在纳秒激光下的烧蚀特性,使用8ns脉宽的Nd:Ya G激光器以反射式和透射式烧蚀GAP固体薄膜靶材,对羽流演化过程和烧蚀坑形态进行了研究。结果表明:反射式烧蚀的羽流中喷射产物以气态为主,固态碎片较少,受迫形成锥面喷射,羽流演化速度较快。透射式烧蚀喷射在约束作用下,有大量固态碎片以球面膨胀,约束在羽流演化的早期抑制了喷射速度,但会逐渐碎裂分解释放产物和能量,使喷射前沿再次加速,约束延长了烧蚀区在靶材滞留的时间,使透射式烧蚀的靶材内热传导效应更为显著。在此基础上,以不同激光能量密度透射式烧蚀靶材,研究透射式烧蚀能量沉积区与周围工质的侵蚀和约束关系。结果表明:激光能量密度越大,周围工质受到的侵蚀作用越强,烧蚀坑面积越大,能量沉积区受到的约束作用越弱,透射式烧蚀的羽流演化体现出部分反射式烧蚀的特征。
Energetic polymers are an important class of propellants in laser ablation micro-propulsion. Poly azide glycidyl ether (GAP) is a typical example of this. In order to study the ablation properties of nanofluorescent films of energetic polymer solid films, Nd: Ya G lasers with 8ns pulse width were used to ablate and ablate GAP solid film targets by ablation and ablation Pit morphology was studied. The results show that the jet products in the reflective ablation plume are mainly in the gaseous state, the solid fragments are less, the conical surface jet is forced to be forced, and the plume evolution rate is faster. Transmitted Ablative Jetting Under the confinement effect, a large number of solid fragments are spherically expanded. Constraints inhibit the jet velocity in the early stage of plume evolution, but will gradually fragment to release product and energy, and the jet front accelerates again to prolong the constraint Ablation zone in the target retention time, so that transmissive ablation target heat transfer effect is more significant. Based on this, the target of laser ablation with different laser energy density was ablated, and the erosion and restraint relationship between the transmissive ablation energy deposition zone and the surrounding working fluid were studied. The results show that the larger the laser energy density is, the stronger the erosion of surrounding working fluid is. The larger the area of ablation pit is, the weaker the confinement of energy deposition zone is. The evolution of transmissive ablation shows partial reflection burning Erosion characteristics.