强激光对燃烧室壳体的热-力毁伤研究

基于ANSYS有限元软件,按有无内压作用,分别对激光辐照下燃烧室壳体的温度场、热应力、应变与损伤进行了计算与分析.分析表明,壳体的温度场分布与光束的功率分布一致,光斑中心温度最高.壳体中应力最大值不在光斑中心,而是位于光斑边缘处,在壳体吸收的激光功率密度超过1 000W/cm2时,壳体中应力大于材料的强度极限,壳体均会发生软化.在存在内部燃气压力的情况下,壳体应力会产生局部集中,沿壳体环向表面通过光斑中心中轴线区域很有可能裂口;相比较无内压的壳体,存在内压的壳体中的应力和产生的形变均大于无内压时的壳体.因此,为达到相同的毁伤效果,在存在内压的情况下,可以适当的降低激光的辐照强度.

Thermal and Dynamics Damage in Combustion Chamber Case under High Power Laser

According to internal pressure effect and without internal pressure effect, the temperature field, thermal stress, strain and the damage of the combustion chamber case under the laser irradiation, are calculated and analyzed respectively, based on the finite element analysis software ANSYS. Analysis results show that, the distribution of the shell temperature field and beam power is identical, and the maximum temperature is at the center of spot. The maximum stress is not in the center, but is located in the flare edg. If the shell absorption of laser power density is lager than 1 000 W/cm2 , the stress of the shell will be greater than limited stress and the shell will soften. In the presence of internal gas pressure condition, shell stress produces a local focus, along the circumferential surface by laser spot center axis region crack probably. Compared with no internal pressure shell, the stress and deformation produced by the shell with internal pressure are greater. In order to achieve the same damaging effects, in the circumstances of exist internal pressure, the laser radiation intensity can be appropriately reduced.