Abstract:
The effects of pressure on NOx
formation and
flame structures in diffusion flames of methyl formate is
investigated. The flames are simulated from the conservation
equations for mass, momentum, energy, chemical species and
equation of state. The results obtained, are validated by
comparison with results obtained from the extensively studied
methane/air and methanol/air flames. A fully infinite
computational domain between two opposed nozzles (one
ejecting pure fuel and the other pure air) has been used for all
the flames. The initial temperature of both fuel and air streams
is taken as 300 K. The flames have been computed at constant
pressures of 1 atm and 50 atm and at a strain rate of 30 s-1. It
has been observed that pressure affects the structure of flames
and formation of various species including oxides of nitrogen in
diffusion combustion of CH4
, CH3OH and CH3OCHO. It has
also been shown that in diffusion flames NO formation in the
three fuels increases with increase in pressure. A comparison of
N, HCN, N2O, CH, O, OH and N2
has shown that NO formation
in diffusion flame mainly occurs through the reaction N2 +
O→NO + N, which is a thermal-NO formation route. Finally, it
is established that increase in pressure results to reduction in
flame thickness due to the high rate of heat release at high
pressures.
