Effects of passive slot and rib configurations on the flow and combustion characteristics of an advanced vortex combustor for a gas turbine

Abstract

In this study, two passive geometric modifications, namely, slotting and rib addition on the sidewall of the front blunt body, are proposed. Numerical simulations are conducted to investigate the effects of these modifications on the flow and combustion characteristics of an advanced vortex combustor under atmospheric pressure conditions, with an inlet velocity of 80 m/s and inlet total temperatures of 300 and 800 K. Results show that both slotting and rib addition promote fuel/air mixing and improve combustion performance at the cost of decreased total pressure recovery coefficient. As the slot depth increases from 0 to 9 mm, the total pressure recovery coefficient exhibits a non-monotonic trend, first decreasing from 97.96% to 97.56% and then increasing to 97.75%. In contrast, increasing rib height from 0 to 6 mm leads to a monotonic decrease from 97.96% to 97.22%. In addition, increasing slot depth from 0 to 9 mm increases the combustion efficiency from 81.64% to 86.87% and decreases the outlet temperature distribution factor (OTDF) from 1.245 to 1.125. A similar improvement is observed with increasing rib height. As the rib height increases from 0 to 6 mm, combustion efficiency increases from 81.64% to 92.60%, with OTDF decreasing from 1.245 to 0.984. These findings provide design guidance for passive geometric modifications of advanced vortex combustors.