Study on characteristics and solution design of gas-filled accumulator in liquid rocket

液体火箭注气式蓄压器特性分析与方案设计研究

¹ School of Astronautics, Beihang University, Beijing 102206, China
² National Key Laboratory of Aerospace Liquid Propulsion, Beihang University, Beijing 102206, China
³ Beijing Institute of Astronautical Systems Engineering, Beijing 100076, China

Received: 1 August 2025

Abstract

The gas-filled accumulator is a supply system component used to suppress the longitudinal oscillation of liquid rockets. To predict the dynamic and static characteristics of the accumulator, and realize its overall design, a gas-filled accumulator partition model is proposed based on the lumped parameter method, which includes the overheated zone, saturated zone, overcooled zone, two-phase critical zone and solid zone. Under the assumption of small pulsation, analytical formulas for accumulator impedance are derived through linearization of the partitioned model. Under the quasi-steady assumption, analytical formulas for the static characteristic parameters, including the temperature of the ullage and bulk liquid, the ullage pressure, and the flow rate inside the overflow pipe, varying with accumulator inlet pressure, are derived in time domain, and the dimensionless parameters characterizing the accumulator's time-domain working characteristics are given. The ullage volume control capability of the gas-filled accumulator is studied, and the calculation method of the accumulator's start-up time, pressure change rate and emptying time was given. Based on the characteristic analysis, the design method and design process of the gas-filled accumulator are proposed, and a design case is given. This gas-filled accumulator solution design method can provide a reference for engineering design.

摘要

注气式蓄压器是一种用于抑制液体火箭纵向自激振荡的增压输送元件。为了预示蓄压器的动、静态特性, 实现蓄压器的总体方案设计, 基于集中参数方法提出了包含过热区、饱和区、过冷区、两相临界区和固体区的注气式蓄压器分区模型。在微小脉动假设下, 通过将分区模型线性化, 导出了注气式蓄压器阻抗的解析公式; 在准稳态假设下, 导出了气液温度、气枕压力和溢流管排量等静态特性参数随蓄压器入口压力变化的解析公式, 提出了表征蓄压器时域工作特性的无量纲参数; 研究了注气式蓄压器的气枕体积控制能力, 给出了蓄压器的起动时间、最大压力变化速率和排空时间的计算方法。在上述特性分析的基础上, 进一步提出了注气式蓄压器方案设计方法和设计流程, 并给出了设计案例。所提出的注气式蓄压器方案设计方法可以为工程设计提供参考。