The Front Cavity Radiation Thermometry

The measurement of temperature take an important part of action in the industry and other scopes. There are many new aspects in the scope of radiation thermometry along with the progress of science and technology,contact radiation thermometry for instance,it's idea is contact the cavity with the measured object firstly,and measure the radiation temperature after thermostability secondly. So the key step is the confirmation of the radiation characteristics of the cavity.We use integral emissivity to describe the radiation characteristics of the cavity,to calculate the integral emissivity,we must know the efficiency emissivity distribution,but it is difficult to measure accurately,so we adopt the calculation method.Besides,we must calculate and analyse in theory before we design a type of cavity,so the scolars from many countries think much of the research of the blackbody cavity theory. The paper uses ANSYS to calculate the efficiency emissivity,the principle is that we divide the blackbody cavity object into finite elements,then solve the thermal balance equation at every node at specific boundary condition and initial condition according to the law of conservation of energy. After getting the node temperature,then we can solve the other physical parameters such as heat flow rate and so on.The paper uses cylindrical cavity as an example,calculates the trend of cavity emissivity along with not only the material emissivity,the ratio of cavity length to radius(L/R),and the ratio of detection distance to radius(H/R) at isothermal distribution,but also the single-wavelength integral emissivity at anisothermal distribution. The results show that the ANSYS emulation results meet the calculation results according to formulas. The calculation results according to formulas reference here is converting the integral equations to the linear algebra equations firstly,and then solving the linear algebra equations iteratively.In practice,in the case that the cavity is out-of-shape or there is an anisothermal distribution,the use of inferential reasoning formula method is complexity,but the use of ANSYS method is very conveniently. The end of the paper introduces a contact radiation temperature measurement system , and it is proved that it has the non-linear characteristic through the experiments.