A numerical investigation on the mechanism of bluff-body lean blowout

In order to control the NOx pollutant emissions and reduce fuel consumption, lean combustion becomes an important subject. A bluff body is used in this paper to study the flame-holding mechanism by numerical simulation. After the validation of the numerical method, 6 cases were simulated with different inlet velocity of the premixed mixture of kerosene vapor and air. The responses of reaction rate near blowout to inlet velocity variation were analyzed. The results show that with the increase of the inlet flow velocity, the anchoring points move upstream to the bluff body, while nearly no movement along the cross direction, and the flame will finally be blown out if the anchoring points are almost attached to the bluff body. It is implied that the quenching effect caused by heat transfer between flame fronts and bluff body is the key factor of flame blowout.