蓄压器膜盒机械刚度对液体火箭POGO振动影响研究

Influences of mechanical stiffness of accumulator on POGO vibration of liquid rockets

在以往的POGO分析中,蓄压器的模型并未考虑膜盒机械刚度。但试验表明,蓄压器金属膜盒具有一定机械刚度,尤其是在受到较大压缩时,机械刚度会很大。较大的机械刚度会降低蓄压器的总柔度,影响蓄压器对POGO的抑制效果。基于气液接触面的力平衡条件和流量连续方程,推导了考虑膜盒机械刚度的蓄压器动力学模型。并将新模型应用于某型号火箭的POGO稳定分析,分析了蓄压器膜盒刚度对POGO稳定性的影响。仿真结果表明,考虑膜盒机械刚度的蓄压器动力学模型比传统模型有更高的计算精度。因此在工程实际中考虑膜盒机械刚度的POGO稳定性分析结果更加准确可靠。

The stiffness of an accumulator was not considered in its POGO analysis previously. But test resultsshowed that an accumulator has a mechanical stiffness when it is compressed, especially, the stiffness is larger when the accumulator is compressed largely. In this case, the accumulator compliance drops, its prevention effect on POGO vibration is affected. Here, based on the flow continuity equation and the force equilibrium equation of Gas-Liquid contact surface, a new dynamic model of an accumulator was derived considering the mechanical stiffness of the accumulator. The model was applied in the POGO vibration analysis of a certain type liquid rockets. The simulation results showed that compared with the original model, the new model has a higher computing accuracy, so the stability analysis for POGO vibration of liquid rockets with the new model is more reliable.