Large-eddy simulation of air-propane premixed combustion affected by centrifugal acceleration

Abstract

Lewis's experimental investigation of the impact of centrifugal acceleration on flame propagation speed posed a novel concept that could shorten combustion chamber length and improve the thrust-to-weight ratio. This work implemented the large-eddy simulation (LES) of air-propane premixed combustion in a closed pipe under centrifugal acceleration on the OpenFOAM software platform. First, using the moving reference frame (MRF) method, the cold flow mixture in the rotating tube was investigated. Then, the combustion of the resulting air-propane mixture at specific centrifugal accelerations (expressed in g) is simulated. Five different cases were considered, including one case without rotation and four cases with centrifugal accelerations of 395 g, 1000 g, 3000 g, and 4000 g. The flame surface wrinkling, a key parameter in premixed combustion, was studied along the longitudinal axis and in the radial direction. For centrifugal acceleration up to 3000 g, the flame surface wrinkling and flame propagation speed raised, but with increasing centrifugal acceleration, these parameters decreased. By investigating the temperature gradient along the longitudinal axis of the pipe, the maximum value occurred in the 4000 g case. The produced pressure wave in the tube was also studied by investigating the instantaneous pressure gradient contour and concluding that the reflected pressure wave does not collide with the flame surface between the flame speed measurement locations.