Numerical Study of Radiation Heat Transfer on Supplementary Firing with Gas Turbine Load Variations

In a combined cycle, it is rare to find the use of supplementary firing in Heat Recovery Steam Generator (HRSG). However, supplementary firing is actually responsible for 200%-400% steam production increase due to additional combustion process inside HRSG. This process evidently produced radiation heat transfer so it is appealing to conduct a further research on it.This study attempts to evaluate 3 dimensional radiation heat transfer in the industrial supplementary firing. Discrete Ordinates (DO) method and Weighted Sum-Gray Gases (WSGGM) model are combined to outline the radiation process, whilst non-premixed with Probability Density Function (PDF) Chemical Equlibrium model is used for combustion analysis. Evaluation is conducted using variations of load 50%, 75%, and 100% of Gas Turbine (GT) industrial datasheet. Validation is build upon load 100% of GT datasheet. Based on the evaluation, datasheet outcome shown that simulation possessed 2.90% and 5.28 % deviation for temperature and pressure respectively. From wall heat flux radiation, this study found that load 50% of gas turbine variation had the best trend, are emit radiation (22413.50 W/m²) and absorb radiation (-11847.5 W/m²) compared to the other options available.