Fuel distribution and evaporation characteristics downstream of an integrated flameholder

摘要

The vapor- and liquid-phase fuel distributions play critical roles in the combustion processes of augmented/ramjet combustors. In this study, the fuel distribution and evaporation characteristics downstream of an integrated flameholder in a fan-shaped test section are investigated under different inflow and fuel conditions using physical and optical methods. The experimental results denote that the Sauter mean diameter (SMD) and liquid equivalence ratio Phi(liquid) at the cross-sections decrease with the increasing inflow temperature T-1, inflow velocity V-1, fuel temperature T-f or flow distance, while increase with an increasing global equivalence ratio phi. The total equivalence ratio Phi(total) is conserved at all cross-sections; thus, the evaporation rate eta at the measurement points increase with increasing inlet conditions and flow distance, similar to the vapor-phase equivalence ratio Phi(vapor). Under a given condition, along the radial direction from the outer wall to the central axis of the fan-shaped test section, the Phi(vapor) and initially increase, then decrease, and finally increase again, and reaching their maximum at a radius of 10/11, whereas Phi(liquid) always increase; note that these trends are not affected by the inlet conditions. In any given cross-section, the SMD and Phi(vapor) variations are significant for increasing V-1 or T-f, whereas they are relatively small for increasing T-1 or phi. This indicates that increasing the V-1 or T-f is more conducive for promoting fuel atomization and evaporation than increasing the T-1 or phi.