Measurement of laminar burning velocities of methanol–air mixtures at elevated temperatures

Abstract

In this paper, the measurement of laminar burning velocities for liquid fuel (methanol)–air mixtures is reported at higher mixture temperatures using externally heated meso-scale diverging channel technique. Laminar burning velocity is determined using mass balance between the channel inlet and flame stabilization location for the planar flames appearing at certain conditions of mixture flow rate and equivalence ratio. A linear temperature gradient in the direction of fluid flow was employed to establish planar, stretch free and nearly adiabatic flames in an externally heated diverging quartz channel. Detailed experiments were carried out for an equivalence ratio range of 0.7–1.3 and a mixture temperature range of 350–650K at 1atm pressure with an uncertainty of ±5% of the actual value. Experimental results are compared with the available results. A good match was observed for Su,0 values at 300K with the literature data and mechanism values. The temperature dependence of laminar burning velocity was also assessed using the correlation Su=Su,0(Tu/Tu,0)α, where α is the temperature exponent. A minimum α value was observed for rich mixtures even at high temperature conditions.