LAMINAR FLAME PROPAGATION OF BIO-GAS, DIESEL AIR MIXTURE NEAR STOICHIOMEETRIC AMBIENT CONDITIONS

Abstract

In the present study, the behaviour of Laminar flame velocity of bio gas air mixture with and without the addition of diesel vapors has been studied. The present investigation attempts to study the effect of. various initial parameters; initial pressure and initial temperature, using pressure time history in a constant volume bomb. Initial pressure was varied over a range of 0.75 atm to 2 atm and initial pressure was varied 303 k to 398 k, the diesel -percentage in the mixture was varied from 0-40%, on energy basis, to simulate the conditions of engine combustion with dual fuel operation. The pressure-time records have been used to calculate the flame velocity, burned gas fraction, flame propagation. etc., using a simplified two zone thermodynamic model assuming equilibrium composition and homogeneous mixture temperature for the burned gases and frozen composition, isentropic compression for the inburned mixture. For each experimental run flame velocities were calculated in a range of 1.5 PO to 0.75 P with the help of a computer program in FORTRAN language. While studying the effect of pressure and temperature on flame velocity, it was observed that flame velocity decreases as pressure increases and flame velocity increases as temperature of unburned mixture increases. The flame velocity of bio-gas air mixture was found more sensitive to temperature when compared with the flame velocity of methane air mixture. With respect to diesel addition it was found that flame velocity increases up to a certain percentage (on energy basis) of diesel addition, but beyond this percentage flame velocity decreases. This may be due to quenching effect of excess diesel. Results of present study are in