Numerical simulation of micro Swiss-roll combustor

To understand the working features of the micro Swiss-roll combustor, numerical simulations for a 2D Swiss-roll combustor were carried out, with CH₄/air multi-step reaction mechanism and radiation from gas to channel wall taken into consideration. Effects of equivalence ratio and flow velocity on combustion characteristics and flame stability were studied. The results show that the Swiss-roll combustor can work with in a wide range of equivalence ratios. But the fuel-rich limit is not symmetrical to the fuel-lean limit. The former is just less than 1, while the later is much larger than 1. For the same equivalence ratio, if velocity is small, flame is stabilized at the entrance of the center region with complete combustion of methane. With the increase of flow velocity, there appears a recirculating zone in the center region, hence increasing the fuel-lean limit and enhancing flame stabilization. But the recirculating zone can decrease the conversion ratio of methane.