EFFECT OF FUEL TYPE ON CONICAL FLAME INSTABILITY

In this paper, the behaviour of conical flame in respect to the coupled perturbation of velocity and equivalence ratio has been investigated. Linearized G-equation is utilized to define the flame dynamics. Burning velocity of a premixed mixture plays an important role in flame dynamics. Fluctuation ofburning velocity due to equivalence ratio oscillation is derived. For this purpose, an empirical model, which includes the properties of a premixed mixture, is utilized. Four governing dimensionless groups emerge inflame dynamics. Beside two well-known dimensionless groups, reduced frequency and the ratio ofburning velocity to the mean axial velocity , two others dimensionless groups emerge from the empirical model of burning velocity and the correlating coupled velocity and equivalence ratio. This analysisintroduces a new parameter, , to study the effects of operating conditions of flame which is a function ofintroduced dimensionless groups. The effects of fuel type, burner geometry, and equivalence ratio are studied.The comparison is made by propane/air and methanol/air indicates the propane/air has higher sensitivity to the perturbation. This Study shows the equivalence ratio can be significantly effective on the flame response

کلیدواژه ها:

linear response ، velocity ، equivalence ratio ، coupled perturbation ، flame instability