Study On The Characteristic Of Blackbody Cavity High Temperature Sensor Based On The Finite Element Method

Temperature is one of the most important physical quantities determining the state ofmatter. So temperature measurement plays important roles in the national defense, military,industrial and agricultural production, scientific experiments. With the development ofdomestic and foreign temperature measurement technology as well as the continuousimprovement of temperature measurement requirements in all fields, a number of commontemperature measurement technologies, such as contact temperature measurementtechnology and the non-contact ones, have been unable to meet the needs of scientific andtechnological development. Hence, research on the new temperature sensor is inevitablefor the development of high temperature measurement technology, and it has broadapplication prospects and economic value.A high temperature blackbody cavity sensor applied in special fields of hightemperature measurement is issued in this paper. Based on the contact & non-contactcomposite temperature measurement technology, this sensor plays an important role intemperature measurement under many special conditions. As the part in direct contact withthe high temperature source measured, the characteristics of the high temperatureblackbody cavity sensor will affect the accuracy and precision of the temperaturemeasurement directly. So this paper mainly analyzes the characteristics of the hightemperature blackbody cavity sensor based on the finite element thermal analysis,including the static and dynamic characteristics analysis of the sensor.According to the theory of blackbody radiation heat transfer and integral equation, itestablishes the mathematic model of integral emissivity of the cylindrical blackbodycavity and gets the theoretical calculation methods of the emissivity. With the method offinite element thermal analysis, it establishes the finite element model of integralemissivity of the sensor cavity, and discusses the influences of the static temperaturemeasurement characteristics of high temperature blackbody cavity sensor affected by thethese parameters, such as the axis length of the cavity, the radius of the underside, thematerial emissivity, the radius of detector surface, the distance between the aperture and the detector. The optimum configuration parameters for the static temperaturemeasurement of high temperature blackbody cavity sensor is designed.Using the finite element thermal analysis to establish the finite element model ofdynamic temperature measurement process of the sensor, the dynamic temperature fielddistribution in the heat transfer process of the sensor is obtained, and it discusses theinfluences of the dynamic characteristics of high temperature blackbody cavity sensoraffected by the these parameters, such as the insertion depth of the sensor, preheatingtemperature, inner and outer structure, convective heat transfer coefficient between thesensor and the measured media. This provides a feasible basis for the structural parametersof the sensor and the proper set of the external temperature measurement conditions.