Abstract: In order to determine characteristic frequencies of acoustic modes of the chamber and their damping characteristics， the corresponding numerical simulation methods based on numerical constant-volume bomb and half-power bandwidth method were developed. Thereby， the most inspirable acoustic mode and the acoustic mode that is the most difficult to be attenuated can be both achieved. Then damping characteristic of a small-thrust attitude and orbit control thruster was predicted by imposing numerical constant-volume bomb at the region near the side-wall. Multi-acoustic modes are stimulated， in which the first tangential mode is the most inspirable acoustic mode， while the first longitudinal mode is the one that is the most difficult to be attenuated. Furthermore， effects of configuration parameters of chamber on its damping characteristic were discussed. With the increase of the diameter of chamber， longitudinal modes are suppressed， while tangential modes are more difficult to be attenuated. With the increase of contraction ratio of chamber， half-power bandwidth of the first tangential mode increases first and then keeps almost the same. With the increase of the length of the cylindrical part， there isn’t obvious trend of half-power bandwidth of each excited mode.

Key words: Pressure oscillations;Acoustic mode;Constant-volume bomb;Damping characteristics;Half-power bandwidth

摘要： 为确定推力室的声学振型频率及其阻尼特性，给出推力室最容易激发声学振型和最难衰减声学振型，建立了基于数值定容弹和半带宽法的推力室声学振型及其阻尼特性的数值模拟方法。对小推力姿轨控发动机推力室进行近圆周壁面的定容弹激励仿真，激发出了多模态的声学振型，其中，一阶切向振型为最容易激发振型，而一阶纵向振型为最难衰减振型。进一步讨论了推力室构型参数对其阻尼特性的影响，结果表明：随推力室内径增大，纵向振型得到抑制，而切向振型变得不易衰减；随推力室收缩比增加，一阶切向振型半带宽先增大后保持不变；随推力室圆柱段长度增加，各振型半带宽没有明显的变化趋势。

关键词: 压力振荡;声学振型;定容弹;阻尼特性;半带宽