基于可调文氏管的液氧流量闭环控制特性研究

Closed-loop control characteristics of LOX mass flow rate based on throttleable venturi

关键词:  液氧供应系统  可调文氏管  变流量  流量闭环控制  流量调节

Key words:  LOX supply system  Throttleable venturi  Variable mass flow rate  Mass flow rate closed-loop control  Mass flow rate adjustment

摘要:

针对液氧供应系统流量精准控制困难的问题，开发了一套流量闭环控制系统并应用于液氧供应系统中。为实现系统按预设目标流量进行输出，进行了四类试验：无控制试验、流量闭环控制试验、PID参数影响试验与流量阶跃调节试验，研究了贮箱压力、液氧温度、针锥位置、调节范围与PID参数等因素对液氧流量闭环控制特性的影响。结果表明，通过反馈实时测得的液氧质量流量，流量闭环控制系统控制可调文氏管节流面积变化，实现了液氧流量±1%的精准控制，解决了由于系统压力波动及液氧温度变化等原因导致的液氧流量供应不稳定的问题，并实现了液氧在5∶1流量变比内的精准阶跃调节。

Abstract:

Aiming at the difficulty of accurate mass flow rate control in LOX supply system， a closed-loop mass flow rate control system is developed and applied on the LOX supply system. Four types of tests are carried out to enable the system to supply at the preset target mass flow rate： uncontrolled test， mass flow rate closed-loop control test， PID parameter influence test and mass flow rate step adjustment test. The effects of tank pressure， LOX temperature， pintle position， adjusting range and PID parameters on the closed-loop control characteristics of LOX mass flow rate are studied. These test results show that by feedback real-time measured LOX mass flow rate， the mass flow rate closed-loop control system controls the throttleable venturi throttling area change， and achieves accurate control of LOX mass flow rate of ±1%， solves the problem of unstable LOX mass flow rate supply due to system pressure fluctuation and LOX temperature change， and finally realizes the precise step adjustment of LOX under 5∶1 mass flow rate ratio.