Numerical investigation on flame blow-off limit of a novel microscale Swiss-roll combustor with a bluff-body

Abstract

A micro Swiss-roll combustor with a bluff-body was proposed for the first time. It is demonstrated that this improved design can greatly extend flame blow-off limit by reducing the flame stretch effect. The flame stabilization ability of this new combustor made of quartz, stainless steel (SS) and silicon carbide (SiC) was numerically investigated using a three dimensional, steady state, k-epsilon turbulence model. The results show that at an equivalence ratio of 0.5, the blow-off limits of quartz combustor, SS combustor and SiC combustor are 40 m/s, 50 m/s and 35 m/s, respectively. Comprehensive analyses were conducted under an inlet velocity of 20 m/s. It was revealled that the heat loss rates for quartz, SS and SiC combustors were 153 W, 108 W and 185 W, respectively. The SS combustor has the best heat-recirculation effect, followed by quartz combustor and SiC combustor. The lengths of recirculation zones are 4.35 mm, 3.4 mm and 3.37 mm for SiC combustor, quartz combustor and SS combustor, respectively. In summary, the heat loss rate is the chief factor responsible for the flame blow-off limit of this novel Swiss-roll combustor. It acts together with the heat-recirculation effect and flow-recirculation effect to determine the flame blow-off limit.