Effects of heat loss on a stagnation-point flow catalytic combustor

Extinction behavior of a stagnation-point flow configured combustor is investigated both numerically and experimentally. While our previous computational studies have identified the lean flammability extension by the catalytic effect, subsequent experimental studies found it difficult to reproduce the similar level of catalytic flammability extension mainly because the burner facility was subjected to a larger amount heat loss. To reconcile these discrepancies, we attempt to reproduce the correct amount of heat loss based on experimental data in order to improve the agreement between the numerical predictions and experimental measurements. By introducing effective heat transfer coefficients that are fitted from the experimental data, it is found that the agreement in the surface temperature and extinction limits are significantly improved. This confirms that a proper estimation of heat loss effect is critical in determining the combustion limits in the stagnation-point flow burner under study. The results also imply that the benefit of catalytic reactions in extending lean flammability limits may be seriously compromised when the compact combustion device is subjected to a larger amount of heat loss.