Effect of Oxygen Enrichment on Laminar Burning Velocity of Methanol and Ethanol – Oxygen – Nitrogen Mixtures

Abstract

The effect of oxygen enrichment on the laminar flames speed for (methanol and ethanol – oxygen – nitrogen) premixed mixtures have been detected practically. Measurement system is designed to measure the laminar flame speed using a tube – method and optical technique (photodiode). Where the flame front position had been located by photodiode. The laminar flame speed measured at atmospheric pressure,301K initial temperature, three level of oxygen concentration (0.21, 0.23 & 0.25), and equivalence ratios from 0.7 to 1.2. All experimental work was carried out at constant pressure in order to use density ratio method for the calculation of laminar burning velocity. Also the dependencies of flame thickness and Zel’dovich number on oxygen enrichment and equivalence ratio were explored. Using Oxygen enrichment techniques increases the laminar burning velocity and decreasing the flame thickness and Zel’dovich number. The maximum value of burning velocity occurs at equivalence ratio (1.1) at all Oxygen level. While the maximum increasing percentage in laminar burning velocity occurs at equivalence ratio (0.7) by (60.5% and 87.7%) for methanol and ethanol respectively. Oxygen enrichment, mixture strength and type of alcohols dependence of burning velocity is represented by empirical relation. Validation of the present work results is approved by comparison with the available published data for (methanol and ethanol – air) mixtures, and show good agreement between them, which indicates that the measurements and the calculations employed in the present work are successful and precise.