Measurement Study On The Casting Surface Multilayers' Emissivity

Temperature is one of determining substance's state reference, so acquiring information about it is very important for science experiment and industry production. In continuous casting surface, the urgent problem to be settled is the detecting of the surface temperature of the continuous casting, because this temperature is the important control parameter of confirming molten steel temperature, adjusting casting speed and it has direct influences on the result of secondary cooling. If the surface temperature can be settled exactly, it is not only providing guarantee for the temperature measuring of the continuous casting's speed and secondary cooling dynamic controlling, but also have direct influence on improving metal quality, speed, reduce costing of energy and safety production. So the study of surface temperature is very important to control cooling models reasonably, adjust casting speed, improve casting flans quality and the successfully running of the whole continuous casting production line. Now, there are two dominating methods to detect the surface temperature via radialization, they are contactive and uncontactive method. And the infrared temperature measuring apparatus is applied in many areas because of its outstanding excellence. After the radiation measurement instruments are installed, the emissivity of surface is becoming the primary factor which bring biggish measuring error. However, the detection of the emissivity is still a difficult problem.This paper has based on the foundation of the emissivity of the rough monolayer and multilayers plane, created the model of casting multilayers surface's emissivity, and calculated the emissivity via the reflective coefficient and the Kirchoff law, simulated and analysed the model.This paper's main content is creation of the casting mltilayers surface's emissivity and the simulation and calculation of the emissivity. According to the Kirchoff law:the object's emissivity is equal to absorptivity in the same temperature, while the absorptivity is equal to 1 subtract the reflectivity, so the emissivity si equal to 1 subtract the reflectivity. In the first step, the paper has created the model of the casting rough multilayers'emissivtiy which based on the model of the monolayer rough surface and the multilayers plane's emissivity. Then calculate the reflectivity of it. At last, we can conclude the emissivity's expressions and simulate it.This paper has researched the theory and sense of the radiative detecting of the temperature, created the multilayer model about the emissivity, calculated the emissivity and presented it on the screen by the Matlab, compared the theory with the fact experimental data. The main content is as follows:Explain the contactive and uncontactive method; has studied the relation between the emisstivity and the scattering coefficient, created the 1-D rough surface by the Gauss method and researched the emissivity and scattering coefficient; work out the formula which can be used to calculate the emissivity based on the multilayer theory, simulate it by Matlab; create the rough multilayer and research its emissivity and simulate it by Matlab, piont out the very factors which can affect the emissivity; compared the simulated curve and the fact data at the end of the paper.According to the simulation and analysis of the monolayer rough surface,the multilayers plane and the casting rough multilayers surface, it has proved that there exist an angle which is called Pseudo-Brewster angle. We can improved the precision while detect the emissivity at this angle. According to the research we can conclude that the result of the model of the casting rough multilayers'emissivity is very close to the practice data, and it is creditable.The innovative point of the paper is to create model of the rough multilayer and calculate the emissivity.