液体燃料ロケットの自励縦振動(ポゴ)

抄録

An analytical study has been carried out to clarify the mechanism of pogo. As a numerical example, the pogo instability of N-Launch Vehicle has been studied. The calculated result is in good agreement with the flight record for the occurrence time of pogo vibration. The following properties have been disclosed. (1) Main factors which govern the pogo occurrence are the mass ratio and the structural damping coefficient. (2) In the case of N-Vehicle, the pogo instability is mainly created at the oxidizer-structure loop with a short feed pipe. (3) The bubble frequency due to cavitation in the oxidizer pump plays an important role.
The effectiveness of an accumulator at the pump inlet as a suppression device is also presented analytically.