低温推进剂测量技术研究及系统实现

Research and Implementation of Cryogenic Propellant Measurement System

当前航天运载器普遍使用低温液氢、液氧及煤油作为推进剂,国内外普遍采用电阻式、电容式、差压式液位测量方案,国外已推出应用于低温液位测量的超声式、雷达式液位传感器。介绍几种低温液位测量方法的原理及应用特点,针对运载火箭高精度、连续、动态液位测量特点及需求,设计一套低温液位测量系统。测量系统包括新型分节电容连续液位传感器、变换器以及液位处理软件,首先将液位信号变换为三角波-线性波双特性电压信号,实现大量程低温液位的分段连续测量,然后利用双特性算法计算液位高度。液位测量系统测量范围为0~20m,测量精度达到±2mm,传感器环境适用温度范围为20K^500K。液位测量系统已在新一代液体运载火箭上推广运用,并已具备工业应用条件。

The current space vehicle generally uses cryogenic liquid hydrogen, liquid oxygen and kerosene as propellant fuel. The resistive, capacitive and differential pressure methods are traditional measurement schemes for cryogenic propellant, which are mainly used at home and abroad, moreover the ultrasonic and radar liquid level sensors have been proposed abroad. This paper introduces the principles and characteristics of several cryogenic liquid level measurement methods. Aiming at the characteristics and requirements of high precision, continuity and dynamic for launch vehicle cryogenic propellant measurement, a cryogenic liquid level measurement system is proposed based on segment capacitance. The system includes a new type of segment capacitance liquid level sensor, transducer and processing software. The liquid level measurement system transforms the liquid level into a double characteristic triangular-linear wave voltage signal, and calculates the liquid level by the proposed double characteristic algorithm. It realizes the measurement accuracy of ±2mm within the range of 0~20m. The sensing temperature range of the liquid level sensor is 20K^500K. The proposed liquid level measurement system has been popularized and applied in the new generation of liquid launch vehicles, and it can also be used in industry.