具有透光性腔壁的黑体空腔测温传感器及其在液体连续测温中的应用

The blackbody cavity sensor is especially suitable for measuring the inner temperature of liquid, due to its good measurement accuracy and stability. However its application is limited by the poor dynamic characteristic. Root causes are that the traditional sensor adopts the opaque material, which results the heat lag from the outer to the inner wall of the cavity. We developed the small-thin wall sensor, which can improve the dynamic characteristic, but not solve it at all. Therefore, this project puts forward a new idea that is the sensor cavity with the translucent wall. It makes that the liquid directly forms the blackbody cavity through the translucent wall, the temperature can be measured rapidly. For the blackbody cavity temperature sensor with the translucent wall, we need to study the mathematical modeling and calculation of effective emissivity for the cavity with the specular-diffuse reflection, transmission and scattering. Studying the radiation characteristics of the cavity, and analyzing the influences of optical properties on the temperature measurement accuracy, including reflectivity, extinction coefficient, albedo and distribution function. Studying the influence of the radiation conduction coupled heat transfer on the response speed of the sensor. Studying and verifying the sensor design method and technology through the experiment and field test. The aim of this work is to develop the radiation temperature measurement theory of blackbody cavity, build the research method of the blackbody cavity sensor with the translucent wall, radically alter the dynamic response characteristic of the traditional blackbody cavity sensor, and realize the rapid, accurate and stable measurement of the liquid temperature.

黑体空腔测温传感器具有良好的测温精度和稳定性，在液体内部测温中极具发展前景。但动态特性差制约了其应用，根本原因是传统黑体空腔采用不透光材料，热量通过腔壁时产生的导热滞后。研制的小型-薄壁腔体虽可改善这一问题，却无法根本解决。为此本项目提出采用透光性材料来构造测温腔体的思想，腔外液体直接形成黑体空腔，以实现快速测温。针对透光性黑体空腔测温传感器，需要研究具有镜漫反射、透射、散射等特性的腔体有效发射率数学建模与计算方法；研究腔体辐射特性，分析反射率、衰减系数、反照率及其分布函数等光学特性对测温精度的影响；研究透光性腔体辐射-导热耦合传热对传感器响应速度的影响规律；通过现场实验，研究和验证传感器及测温系统的实现方法。目标是完善黑体空腔辐射测温理论，建立透光性黑体空腔测温传感器的研究方法，根本改变现有传感器动态响应特性，为其广泛应用于液体内部温度快速、精确、稳定地连续测量奠定基础。

黑体空腔测温传感器具有良好的测温精度和稳定性，在液体内部测温中极具发展前景。但动态特性差制约了其应用，根本原因是传统黑体空腔采用不透光材料，热量通过腔壁时产生的导热滞后。研制的小型-薄壁腔体虽可改善这一问题，却无法根本解决。为此本项目提出采用透光性材料来构造测温腔体的思想，腔外液体直接形成黑体空腔，以实现快速测温。. 与传统黑体空腔相比，透光性腔体内的光线传播过程具有镜-漫混合反射、透射、吸收、散射等新特性，这些光学特性对传感器腔体辐射特性及结构设计具有重要影响，重点研究内容如下：（1）研究具有透光性腔体有效发射率数学建模与计算方法，建立了适用于半透明材料的界面双向反射分布函数，构建了透射、吸收、散射等特性的概率模型，基于Monte-Carlo法建立了适用光学特性、结构形状、温度分布的有效发射率计算模型。（2）基于有效发射率计算模型，研究了透光性材料光学特性（如：透射率、反射率、发射率、折射率，散射反照率等）对黑体空腔的辐射特性的影响。针对不同透光性条件下，基于传感器测温精度要求，设计合理的腔体结构形状。（3）建立透光性腔体的辐射-导热耦合传热模型，研究材料光学特性对传感器升温速度的影响，研究透光腔壁空间不等温性分布对测温精度的影响。基于测温精度要求，研究传感器动态响应特性，进而确定传感器响应速度。（4）实验研究理论模型的正确性，测试响应速度和测量精度。以石英玻璃为腔体材料，圆柱斜底腔体为例，传感器静态测温误差≤±0.5℃（测温范围：400~1000℃）；急速升温实验表明，其动态响应速度显著高于热电偶。. 本研究突破了传统不透明黑体空腔传感器动态响应慢的瓶颈问题，完善黑体空腔辐射测温理论，构建了透光性黑体空腔测温传感器的研究方法，为其广泛应用于液体内部温度快速、精确、稳定地连续测量奠定基础。