Effect of Swirl Strength to Axial Flow Development Inside the Can Combustor

Abstract

The main purpose of this paper is to study the internal flow effect of varying the swirl number inside the combustor. The flow field inside the combustor is controlled by the liner shape and size, wall side holes shape, size and arrangement (primary, secondary and dilution holes), and primary air swirler configuration. Air swirler adds sufficient swirling to the inlet flow to generate central recirculation region (CRZ) which is necessary for flame stability and fuel air mixing enhancement. Therefore designing an appropriate air swirler is a challenge to produce stable, efficient and low emission combustion with low pressure losses. Four radial curve vane swirler with 30o, 40o, 50o and 60o vane angle corresponding to swirl number of 0.366, 0.630, 0.978 and 1.427 respectively were used in this analysis to show vane angle effect on the internal flow field. The flow behavior was investigated numerically using CFD solver Ansys 14.0. This study has provided the characteristic insight into the flow pattern inside the combustion chamber. Results show that the swirling action is augmented with the increase in the swirl number, which leads to increase in the turbulence strength, recirculation zone size, and amount of recirculated mass. The current study report that the 50° swirler (swirl number > 0.7), produced enough swirling flow to generate good CRZ in the combustion chamber