Research on the principle of space high-precision temperature control system of liquid crystals based Stokes polarimeter

The magnetic field is one of the most important parameters in solar physics,and a polarimeter is the key device to measure the solar magnetic field.Liquid crystals based Stokes polarimeter is a novel technology,and will be applied for magnetic field measurement in the first space-based solar observatory satellite developed by China,Advanced Space-based Solar Observatory.However,the liquid crystals based Stokes polarimeter in space is not a mature technology.Therefore,it is of great scientific significance to study the control method and characteristics of the device.The retardation produced by a liquid crystal variable retarder is sensitive to the temperature,and the retardation changes 0.09°per 0.10℃.The error in polarization measurement caused by this change is 0.016,which affects the accuracy of magnetic field measurement.In order to ensure the stability of its performance,this paper proposes a high-precision temperature control system for liquid crystals based Stokes polarimeter in space.In order to optimize the structure design and temperature control system,the temperature field of liquid crystals based Stokes polarimeter is analyzed by the finite element method,and the influence of light on the temperature field of the liquid crystal variable retarder is analyzed theoretically.By analyzing the principle of highprecision temperature measurement in space,a high-precision temperature measurement circuit based on integrated operational amplifier,programmable amplifier and 12 bit A/D is designed,and a high-precision space temperature control system is developed by applying the integral separation PI temperature control algorithm and PWM driving heating films.The experimental results show that the effect of temperature control is accurate and stable,whenever the liquid crystals based Stokes polarimeter is either in the air or vacuum.The temperature stability is within±0.0150℃,which demonstrates greatly improved stability for the liquid crystals based Stokes polarimeter.

SiC晶体测温判读技术研究

针对航空发动机热端部件表面温度准确测量的需求,开展了SiC微型晶体测温判读技术研究。采用中子辐照技术破坏SiC晶体的有序结构,使晶体内部产生缺陷,再通过退火处理消除晶体内部缺陷。拉曼光谱分析结果表明,晶体内部残余缺陷浓度随着退火温度的升高而降低。X射线衍射结果显示,样品的衍射角和半高宽分别随退火温度的升高以近似线性的趋势增大和降低。根据晶格参数可以得到温度标定数据库与标定曲线。采用Matlab编写了SiC晶体测温判读软件,判读软件的测温范围为500~1400℃,判读误差为0.447%。

SiC晶体测温技术研究

针对航空发动机结构复杂和工况条件苛刻的问题,研究基于SiC晶体材料的测温技术,解决航空发动机燃烧室、涡轮和尾喷管等高温部件的测温难题。选取国产6H-SiC晶体作为材料,进行6H-SiC晶体的中子辐照。研究晶体测温的温度判读方法,提出X射线衍射峰半高宽作为温度判读参数,测量温度可达1 600℃,测量精度达到1%,比国外晶体测温技术的测温范围更高。该测温技术具有微尺寸、微质量、无引线的非侵入式优点,可用于航空发动机及燃气轮机的高温测量。

辐照碳化硅测温晶体温度标定试验感温过程分析研究

辐照碳化硅测温晶体是航空发动机研制过程中热端旋转部件温度测量的重要方法,其测量精度依赖于对其温度-缺陷浓度响应关系的精准标定,标定过程可分为温度标定试验、晶体缺陷表征测量、标定曲线建立3个阶段。温度标定试验中,温度场的波动、测温晶体与测温热电偶感温偏差以及非理想因素导致的传热是辐照晶体技术测量误差的重要来源。利用实验和数值方法,研究了辐照测温晶体在温度标定试验过程中不同阶段下主导的传热传质过程,分析了支杆材料的热物理参数、温度过冲以及准热平衡状态下的温度扰动对于测温晶体感温的影响,结果发现测量误差主要由辐射场在轴向方向的不均匀分布所导致,最后对支杆的材料和结构设计提出了相应的改进方案。

基于缺陷回复的晶体测温技术及其在工程技术领域的应用研究

高超飞行器表面、航空发动机叶片等重大装备关键高温构件工作环境极端恶劣,且处于高速运动或转动工作状态,高温热作用将直接影响构件工作性能及寿命,甚至威胁装备安全。由于工作环境和工作状态的极端性,传统的热电偶、示温漆以及薄膜热电偶等测温方法,已无法满足极端工况(高温、高压、高转速、高负荷等极端工况)复杂构件表面极限高温精准获取,迫切需要创新性发展新的无源分布式测温技术,增强我国在航空装备研发方面的科技实力。本文介绍的晶体温度传感技术有望解决以往测温技术测温上限低、测温系统复杂、受工况环境和空间限制等难题,可实现关重件表面温度精准测量。该技术基于晶体缺陷高温回复,可对工作目标异域分时进行温度读取,对解决在役在研关重件工作极限高温精准测量具有重要意义。