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

doi:10.3964/j.issn.1000-0593(2022)01-0310-06

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Abstract 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 1 000 K. The spectral emissivity of each specific high-temperature point was tested at 4 μm, 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.

Key words：Non-conductive; High temperature; Spectral emissivity; Measurement; Laser rotation; Entirety black body method

Received: 2020-08-12 Accepted: 2020-12-05

ZTFLH:

O433.1

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https://www.gpxygpfx.com/EN/10.3964/j.issn.1000-0593(2022)01-0310-06 OR https://www.gpxygpfx.com/EN/Y2022/V42/I01/310