A review of flame radiation research from the perspective of factors affecting the flame radiation, measurement and modeling

Abstract

Radiation plays a significant role in heat transfer within combustion chambers. Therefore, the flame radiation as well as the related calculations, modeling and measurements are important factors in the investigation of combustion chambers and flames. In this paper, it is attempted to study the factors that affect the amount of flame radiation including turbulence fluctuations and the interaction between turbulence and radiation, re-absorption, and luminosity. Factors such as the increase in Reynolds number and increase in oxygen availability can increase the effective radiation. In addition, a review over the measurement tools, models and approximations proposed in flame radiation modeling is performed. Having their own advantages and disadvantages, the approximations used to simplify the radiation calculations are selected in certain circumstances while the k-scaled method works consistently better for full-spectrum computing. In terms of reliable radiation measurements, interference with radiation emitted from the walls and the flame radiation reflected by the walls should be considered in the measurement of flame radiation in confined chambers. It is important when the surface temperatures are high or when the surfaces are highly reflective especially when investigating the changes in flame radiation due to variations in operating parameters such as the stoichiometric ratio and swirl number. In regard to Turbulence Radiation Interaction (TRI) absorption, it can be said that in sooty flames, TRI absorption can be disregarded at a laboratory scale but it is influential in flames at an industrial scale or high pressure systems.