灰色壁に囲まれた非灰色ガスのふく射伝熱高速解析手法の開発 Development of Fast Algorithm for Radiative Heat Transfer in Non-Gray-Gas Systems Surrounded by Gray Walls

博士論文

A fast algorithm is developed to solve radiative heat transfer problems in non-gray gas system surrounded by gray walls. In the problem, the distributions of the gas temperature and the wall heat flux in non-gray-gas system are estimated. In the present study, the time consuming Monte Carlo procedure used for radiative transfer calculation is successfully pushed out of iterational loop of the temperature convergence. For the purpose, the calculational procedure of READ values, the ratio of the radiative energy absorbed by an element to the energy emitted from a source element, are separated into two parts, the absorption-coefficient-dependent part and independent part. And by using the present procedure, the former absorption-coeflfricient-dependent part of the caiculation of READ values, which should be in the temperature convergence loop, can easily be calculated using the absorption-coefficient independent part, which require the Monte Carlo procedure to be calculated but the Monte Carlo procedure to can be situated outside the loop. The calculated values of READ are used to calculated direct exchange areas for the zone method to obtain total exchange areas in systems surrounded by gray walls. The new method, the fast READ method combined with the zone method, reduces the computation time by one-sixth compared to the conventional non-gray radiation heat transfer calculation using the READ method. Comparison between the results of the present method and exact solution shows the validity of the present method.