具有快速响应特性的黑体空腔式钢水温度连续测量传感器

Temperature measuring method of blackbody cavity solves a worldwide problem in metallurgical measurement field that is temperature continuous measurement of molten steel. It has been applied in 15 and 58 steel companies in foreign and domestic respectively. The biggest problem of the existing sensor is the response lag of 6~8 min, leading to the poor dynamic nature, which results in that it cannot achieve continuous real time monitoring of molten steel temperature in overall process. Root causes are that the sensor adopts the "big size - thick wall - double layer" structure and Al2O3-C material with high thermal resistance. Therefore, this project puts forward a design philosophy of the new sensor that is a blackbody cavity sensor with "small size - thin wall - single layer" structure and cermet material. Implementation methods for technical performances of the sensor are investigated, including the following contents. (1) Based on the requirement of heat transfer and corrosion resistance, the wall thickness and components of this cavity are optimized, which coordinately solves the problem between response speed and lifetime, compounding with the Al2O3-C material for reducing the cost. (2) The work establishes a model for calculating the effective emissivity of the new cavity, studying the problem of temperature measurement precision, which is used to design the miniature cavity. (3) The coupling model of the temperature field - flow field - concentration field inside the sensor is established under the effect of micro-positive pressure gas, which is studied to solve the fume disturbance problem caused by the single-layer structure, ensuring the stability of temperature measurement. The aim of this work is to shorten the response time of the sensor to less than 30 s, radically altering the dynamic response characteristic of the blackbody cavity sensor for measuring the molten steel temperature continuously.

黑体空腔测温方法解决了钢水温度连续测量这一冶金检测领域的世界难题，并已在国外15家、国内58家钢铁企业应用。现有传感器最大问题是响应滞后达6～8min，动态特性差，无法实现钢水温度全过程连续实时监测。其根本原因是传感器采用"大尺寸-厚壁-双层"结构与高热阻Al2O3-C材料。 为此本项目提出基于结构与材料的新型传感器设计思想，即"小型-薄壁-单层"金属陶瓷材质的黑体空腔传感器。研究其技术性能的实现方法，包括：（1）基于传热与抗侵蚀需求优化腔体壁厚和成分，协调解决响应速度与寿命问题，并与Al2O3-C复合降低成本。（2）建立新型腔体的有效发射率计算模型，研究测温精度问题，设计小型化腔体。（3）建立微正压气体作用下传感器内流场-温场-浓度场耦合模型，研究解决单层结构引起的烟气干扰问题，保证测温稳定性。目标是将传感器响应时间缩短至30s内，根本改变黑体空腔钢水连续测温传感器的动态响应特性。

钢水温度连续测量是冶金检测领域的世界难题，黑体空腔测温方法实现了对钢水的高精度、低成本连续测量。但现有传感器最大问题是响应滞后达6～8min，动态特性差，无法实现钢水温度全过程连续实时监测。其根本原因是传感器采用"大尺寸-厚壁-双层"结构与高热阻Al2O3-C材料。为解决该问题，本项目从传感器结构和材料设计角度出发，提出了一种具有快速响应特性的“小型-薄壁-单层”金属陶瓷材质的新型黑体空腔传感器。. 本项目针对传感器测温精度、稳定性、寿命与成本等技术性能的实现方法进行了深入研究。重点研究了如下内容：（1）传感器感温材料（金属陶瓷）与基体材料的成分组成与性能，实验测试其抗侵蚀性、热震性、抗氧化性，分析制作工艺对材料性能的影响规律，为协调优化传感器响应速度与使用寿命奠定了基础；（2）建立了新型复合腔体的有效发射率计算模型，研究了腔体结构尺寸、材料辐射特性、等温性以及探测器响应波段、光学系统等对测温精度的影响，为精确设计小型化腔体奠定基础；（3）建立微正压气体作用下传感器内流场-温场-浓度场耦合模型并通过实验验证其准确性，以此为基础研究了主动屏蔽烟气干扰的方法，计算分析了非等温条件下，其对传感器测量精度的影响，确保测温稳定性；（4）开展传感器现场实用化技术研究，主要对传感器测温精度、响应速度、稳定性、寿命等性能。在南京钢铁集团公司和鞍山钢铁集团两个现场进行测试。. 传感器测温误差≤±3℃（测温范围：800~1600℃），平均寿命≥25小时；响应时间在30s以内，根本改变黑体空腔钢水连续测温传感器的动态响应特性。进一步完善了在线黑体空腔测温理论，为其在更广泛的领域应用奠定了坚实基础。