| Emissivity,as a very important thermophysical parameter,can characterize the radiation ability of an object.It is not only related to wavelength and temperature,but also to the surface structure,oxidation degree and coating of the object.In order to measure and study the hybrid surface emissivity,two kinds of hybrid surface cavity arrays are designed and fabricated as emissivity samples.One is the deep continuous tapered cavity array,the other is the deep continuous tapered symmetrical cavity array.The factors affecting the emissivity of hybrid surface are analyzed theoretically.It is concluded that the main factors affecting the emissivity are the temperature of the object,the inclination angle of the array and the structure.The surface of the hybrid cavity array is divided into 5 units,each with a circular area of 5 diameters and 5 wings.According to the principle of contact thermometer measurement method,a set of experimental scheme based on infrared thermometer and a set of experimental scheme based on infrared thermal imager were built,and the stability and accuracy of the two experimental schemes were verified.Then,by changing the factors affecting emissivity,the emissivity of hybrid surface is measured with two experimental schemes.In order to further study the mixed surface emissivity,the theoretical emissivity values of each unit are calculated theoretically,and three models are established to fit the measured data.Then the theoretical calculated values are compared with the experimental measured values,and the accuracy of the experimental measured values is analyzed.Finally,the influence factors of the mixed surface emissivity are analyzed.The results show that the surface emissivity decreases with the increase of temperature,increases first and then decreases with the increase of rectangular groove depth,but the decrease is not obvious,and increases with the increase of array tilt angle.Whether symmetrical structure has little effect on the surface emissivity of samples. |
PDF Full Text Request