Influence of turbulence-radiation interaction on the radiative heat transfer to the wall of large-scale industrial furnaces and temperature distribution in the furnaces

Abstract

Theoretical examinations based on absorption line databases were carried out about the influence of turbulence-radiation interaction on the radiative heat transfer arriving at the wall of large-scale industrial furnaces, where the re-absorption of radiative energy by combustion gas on its path toward objects to be heated cannot be neglected. In this study, the efficient and accurate calculation method for non-gray analysis and the effective method for handling turbulent fluctuations of radiation and absorption proposed in our previous paper were coupled. Combining the above coupled method and a governing equation solver for obtaining the spatial distribution of time-averaged values of temperature, concentration, velocity and so on, the heat transfer including radiation in large-scale industrial furnaces enveloping turbulent flames was able to be evaluated with sufficient accuracy equivalent to Line-by-Line analysis and with feasible calculation load. By applying this calculation technique to large-scale furnaces, it was found that negligence of turbulent fluctuation in numerical simulation gives rise to obvious change in heat flux distribution on the side wall and in the spatial distribution of time averaged temperature. In addition, change in the total amount of radiative energy arriving at side wall caused by negligence of turbulent fluctuations is fairly small compared with change observed in the case of a typical optical path indicated in our previous report.

Keywords

• thermal radiation
• turbulent combustion
• numerical simulation
• radiative wall heat flux
• large-scale industrial furnaces
• turbulence-radiation interaction
• line-by-line analysis