Research On The Characteristic Of The P-Polarized Directional Emissivity Of High Temperature Steel Billet

The pseudo-Brewster angle shows the maximum emissivity value of the metal surface in the p-polarized direction.It is the key to measure the metal surface brightness temperature since p-polarized emissivity is similar to the blackbody emissivity.Besides,problems such as brightness temperature distortion caused by metal surface roughness and oxidation have been resolved,too.Therefore,it is valuable to research pseudo-Brewster for its application in accurate temperature measurement.This thesis is focused on the topic of steel surface p-polarized emissivity of high temperature.This thesis measures billet's emissivity in a vacuum chamber between 900?and 1000? based on related measurement principles with the equipment of measurement device.In addition,this thesis also carried a series of p-polarized directional emissivity experiments under different roughness and oxide thickness and to analyze their impacts on the emissivity.Here is the main content:(1)This research,based on the electromagnetic wave propagation theory as well as Maxwell's theory,has analyzed the polarized emissivity characteristics and discussed the variation trend of the actual metal surfaces spectral emissivity under different influence factors.(2)This research has designed a measurement scheme,which measured the high temperature billet' s emissivity in a vacuum chamber and accomplished the selection of CCD parameters as well as the conversion of gray to temperature.(3)This research has analyzed the oxide skin formation mechanism of the steel billet and prepared different oxide thickness of the samples.(4)This research has experimentally studied a series of p-polarized directional emissivity under different roughness and oxide thickness,also analyzed their impacts on the emissivity.The experimental results have been compared with the results of the Japanese scholars.The reliability of the experiment has been confirmed.To sum up,here are the experimental results:(1)The pseudo-Brewster angle does exists on the rough surface of steel.(2)The pseudo-Brewster angle does not exists when the thickness of the steel oxide film reaches 5?m and does exists when less than 1?m.(3)The pseudo-Brewster angle does not alter during the growth of the surface roughness and the thickness of steel oxide film.(4)The pseudo-Brewster angle does move to small angle with the increasement of temperature.