Effect of Flame Radiative Heat Transfer in Horizontal-Type HRSG with Duct Burner

Abstract

A method was developed for analyzing the radiation heat transfer from the duct burner flame to the heat exchanger in a heat recovery steam generator (HRSG) in order to supplement the existing thermal design process. The burner flame and the heal exchanger were considered to be imaginary planes, and the flame temperature, surface, and emissivity were simplified using an engineering approach. Three analysis eases in which the duct burner position and fuel were changed were considered. The calculated flame radiative heat transfer and local flux on the healing surface were compared with those of 3-atomic gas radiation and convcction. In all analysis eases, heat transfer by 3-atomic gas radiation was very small. The ratio of the flame radiative heat transfer to the convection heat transfer on the heating surface was estimated to be as high as 8-41%. Moreover, the local heat flux on the heating surface cenierline was dominated by flame radiative heat flux.