基于激光旋转加热的非导电材料高温光谱发射率测试方法与装置

光谱发射率是表征材料热物理性能的重要参数。对于非导电材料的高温光谱发射率测试，一般采用高温加热炉加热或辐射加热的方式来进行发射率测试，存在的问题是采用高温石墨炉加热时，样品可能会与高温石墨发生化学反应，从而破坏材料原有物性；采用辐射加热，一般是单向静止加热，会存在样品温场梯度非均匀分布的问题。基于激光旋转加热和样品/黑体整体一体化设计，提出了一种“样品动中测”的非导电材料高温光谱发射率测试新方法，建立了相应的测量模型，突破了传统的 “样品静中测”的局限，样品与参考黑体共形一体化设计，采用微区域光谱辐射成像方法，同时测量参考黑体和样品的光谱辐射能量与温度。建立了激光旋转加热状态下的热传导方程，对典型样品材料的温度分布进行了仿真计算，结果表明旋转样品温场分布较为均匀，分析了温场分布与红外光谱发射率测量误差间的关系，给出了适用于本测试方法的材料的热导率下限值。基于该方法，搭建了相应的测量装置，对典型材料碳化硅在1 000 K时的光谱发射率进行了测试，在4 μm处对各个典型高温温度点的光谱发射率进行了测试，得到了碳化硅材料在红外波段的光谱发射率波长变化和温度变化规律特性。与国外的测量结果进行了比对，结果较为一致，验证了激光旋转加热光谱发射率测试方法的可行性。采用此方法，不破坏样品本身的理化特性，样品加热升温速度快，测量温度范围上限高，有效减小了激光静止单向加热带来的温度不均匀性，可同时测量出样品和参考黑体的光谱辐射亮度及温度，无需另外再设计标准高温黑体，解决了现有非导电材料高温光谱发射率测试中非均匀加热和辐射能量同步比对测量的问题，可应用于多种非导电材料高温光谱发射率的测试。

Method and Device for Measuring High-Temperature Spectral Emissivity of Non-Conductive Materials Based on Laser Rotation Heating

Emissivity is an important parameter to characterize the thermophysical properties of materials.For non-conductive materials,high-temperature furnace heating or radiant heating is generally used in emissivity measurement.The problem in high-temperature furnace heating method is that tested materials may chemically react with the material of the heating container,thereby destroying the original characteristics of the materials.There will be problems of non-uniform heating of samples in the radiant heating method.The tested materials are usually heated unidirectionally and still in the radiant heating method,so there will be samples non-uniform distribution of sample temperature gradient.Based on laser rotating heating and sample/black body integrated design,this paper proposes a new method.The samples are spinning while measuring,measuring the emissivity of non-conductive materials at high temperature,and establishing a corresponding measurement model.This method break through the limitations of traditional measurement methods,in which the samples are still while measuring.The sample and black body are designed integrally,and the micro-area spectral radiation imaging method is adopted to measure the spectral radiation energy and temperature of the black reference body and the sample at the same time.The heat conduction equation under the laser rotating heating state is established,and the temperature distribution of typical sample materials is simulated.The results show that the temperature field distribution of the rotating sample is relatively uniform.The relationship between the temperature field distribution and the infrared spectral emissivity measurement error is analyzed.The lower limit of the material thermal conductivity applicable to this test method is shown.Based on this method,a corresponding measurement device was built to test the spectral emissivity of a typical material silicon carbide at 1000 K.The spectral emissivity of each specific high-temperature point was tested at 4μm,and the silicon carbide material was measured at The characteristics of the spectral emissivity wavelength change and temperature change rule characteristics of the infrared band.The results are compared with the foreign measurement results,and the results are relatively consistent,which verifies the feasibility of the laser rotating heating spectral emissivity test method.The characteristics of the spectral emissivity wavelength change and temperature change rule characteristics of the silicon carbide material in the infrared band are obtained.The results are compared with the foreign measurement results,and the results are relatively consistent,which verifies the feasibility of the laser rotating heating spectral emissivity test method.With this method,the physical and chemical characteristics of the sample are not destroyed,the sample heats up quickly,the temperature field in the measurement area is uniform,the upper limit of the measurement temperature range is high,and the temperature unevenness caused by the laser static and unidirectional heating is reduced effectively.The sample’s temperature and spectral radiation energy can be measured at the same time,so the standard high temperature black body does not need to be designed separately.This method solves the existing high-temperature non-uniform heating and radiant energy synchronous comparison measurement in non-conductive materials emissivity measurement.It can be applied to measure the high-temperature spectral emissivity of various non-conductive materials.