低温液氧过冷方案对比分析与试验研究

Comparative investigation and experimental verification on depth subcooling schemes of cryogenic liquid oxygen

从燃料密度、显冷量和贮箱增压压力等方面阐述了采用过冷液氧推进剂的性能优势。以获取66 K过冷液氧为目标,从低温工质消耗、功率消耗、系统复杂性和安全性等多个方面对液氧抽空减压、负压液氮浴换热和氦制冷循环3种过冷方案进行了定量与定性对比。针对液氮浴过冷技术进一步对比了单级与两级过冷方案,最终建议采用常压+负压两级液氮浴过冷方案获取66 K深度过冷液氧,并基于该方案搭建了半工业级液氧深度过冷验证平台,成功将液氮过冷至66 K以下。试验表明在0~3 L/s的液氧流量范围内,由于管道漏热,液氧过冷加注过程中其温度随着流量增大而降低。本试验验证了两级液氮浴过冷方案的可行性,为低温火箭发射场推进剂加注系统升级提供了理论及技术参考。

The advantages of using subcooled liquid oxygen were illustrated in terms of density,apparent cooling capacity and pressurization pressure of the tank.For the purpose of acquiring 66 K subcooled liquid oxygen,three subcooling schemes,including:liquid oxygen evacuation,negative pressure liquid nitrogen bath and helium refrigeration cycle,were quantitatively and qualitatively compared from the perspectives of cryogenic mass consumption,work consumption,system process complexity and system security.The single-stage and two-stage subcooling schemes were further compared for the liquid nitrogen bath subcooling technology,and the two-stage liquid nitrogen bath subcooling scheme was finally recommended to acquire 66 K depth subcooled liquid oxygen.A semi-industrial experimental system of subcooled liquid oxygen acquisition was established based on the two-stage subcooling scheme,and liquid nitrogen was successfully subcooled to below 66 K.The experimental results showed that within the flowrate range of 0−3 L/s,the temperature of liquid oxygen in the process of subcooling filling decreased with the increase of flowrate due to the pipeline heat leakage.The feasibility of the two-stage liquid nitrogen bath subcooling scheme was verified by this experiment.This research could provide a theoretical and technical reference for the upgrading of propellant filling systems at launch sites for cryogenic rockets.