Precise Calculation of the Integrated Emissivity of Baffled Blackbody Cavities

There are some methods to calculate the integrated cavity emissivity. Because of the existence of the penumbral region, the results obtained from these methods deviate from the exact values. In this paper, we pay special attention to solve the penumbral region problem and put a new method to calculate precisely the integrated cavity emissivity of the diffuse conical and cylindrical cavity. This method can also be used to calculate for isothermal or non-isothermal, symmetric-axis, diffuse cavities. Some numerical and typical results are also given here.