pogo analysis and accumulator design for the pr-2 launch vehicle
- Paper ID
98195
- DOI
- author
- company
CAS Space
- country
China
- year
2025
- abstract
The Kinetica-2 (PR-2) developed by CAS Space is a 12-ton class medium-sized liquid launch vehicle. During its flight, the coupling between the airframe structure system and the propulsion system can cause longitudinal instability vibrations (POGO). Pogo suppression is a key challenge that large liquid rockets must overcome. The Kinetica-2 addresses this issue by installing a constant-pressure gas accumulator on the pump inlet pipeline to alter the natural frequency of the propellant delivery pipeline system, thereby suppressing the occurrence of Pogo vibrations. This accumulator uses three stainless steel bellows as gas-liquid separation membranes, with a cryogenic capacityof up to 2.25 MPa.L. The diaphragm material is 0.35 mm thick stainless steel, and multiple diaphragm pairs are welded together to form a sealed chamber, with a maximum volume of 2.5L. The stainless steel bellowsis simple in material and has advantages such as resistance to low temperatures, high energy value, good pressurization stability, and long fatigue life under reciprocating movement and high-frequency random vibration fatigue. The bellowsis designed to withstand an internal pressure of 0.9 MPa (absolute pressure), and the airframe completes a one-time gas charging at room temperature in a horizontal position. The 6-minute mechanical environmental random vibration test confirms compliance with an RMS 40g vibration requirement.This paper provides a detailed introduction to the Pogo analysis of the launch vehicle, the design plan for the cryogenic metallic diaphragm accumulator, experimental data, and its application effects.