Investigating the effect of induced centrifugal force resulting from duct geometry on the propagation speed of premixed flame using OpenFOAM software

Increasing the propagation speed of the flame due to centrifugal force can lead to reducing the length of the combustion chamber and increasing the thrust-to-weight ratio in air gas turbine engines. The effect of centrifugal force on the propagation of the premixed flame has been investigated. For this purpose, the large eddy simulation of premixed combustion of the air-propane mixture in two straight and curved ducts with a step in the outer wall as a flame holder was performed using OpenFoam software and compared with the experimental data. The ducts have an inlet and outlet, and the averaged temperature and the wrinkling (the ratio of laminar to turbulent flame speed) were investigated for two different inlet velocities. It was observed that the curved duct inducing centrifugal force to the fuel and air mixture causes better mixing and wrinkling, increases the area of the flame, and as a result, the speed of flame propagation was improved. Also, the curved duct can withstand increasing the inlet velocity to higher values. To study the effect of fluid circulation, a new duct geometry for more mixture circulation was designed and analyzed. The comparison of temperature and wrinkling parameters in the outlet section for two initial curve ducts (C2) and the new one (C3) showed that the increase in the rotation due to the increase in centrifugal force improved the average temperature and wrinkling parameters in the outlet.