PERFORMANCE COMPARISON OF AERO-ENGINE THRUST AUGMENTORS STABILIZED BY BLUFF BODY FLAME HOLDERS AND A FLAME-HOLDER-LESS CONCEPT

摘要

This study investigates the performance benefits of a flame-holder-less flame stabilization concept for thrust dugmentors compared to the common flame holder design. The concept proposes to burn a small portion of the augmentor fuel in a rich mixture with air bled from the compressor to produce a highly reactive partially oxidized fuel-air mixture (POx). The POx mixture is injected into the turbine exit flow to enhance combustion kinetics in order to achieve stable combustion in the augmentor. Thermal efficiency during wet and dry operation is compared, taking into account both the pressure losses due to the flame holders and the reduction of core air for the flame-holder-less concept. Furthermore, the thrust-to-weight ratio and the corresponding flight range have been investigated with respect to the system weight and the induced losses.It was found that the thermal efficiency during dry operation is significantly increased when the pressure losses of the flame holders are eliminated. During wet operation, it was calculated that aflame holder system with only 2 % total pressure loss of the flow would operate at the same thermal efficiency as the flame-holder-less concept when 3 % air is bled from the compressor. If, for an engine operating at these conditions, the flame-holder-less system could maintain stable combustion using less than 3 % bleed air, it would increase the thermal efficiency of that engine during wet operation. The results also suggest that a flame-holder-less system is lighter weight and has the potential to increase engine thrust-to-weight ratio and extend flight range when compared to aflame holder system designed to operate at the same overall engine thermal efficiency.