Effect of cavity-air injection mode on the performance of a trapped vortex combustor

Abstract The cavity has been widely used in subsonic and supersonic flows for flame stabilization. Moreover, significant efforts have been put on the combustion and flow characteristics of the cavity under a variety of cavity-air injection strategies. However, few attentions have been paid so far on the cavity-air injection mode. In this paper, experimental and numerical studies were conducted to investigate the effect of the cavity-air injection mode on the combustion and flow characteristics of a trapped vortex combustor (TVC). The present work was performed under atmospheric pressure with an inlet temperature of 473 K. The effects were directly explored in terms of ignition, lean blowout limit, combustion efficiency, cavity flow field, and turbulence intensity with an injection hole and an injection slit, respectively. The experimental results indicated that the ignition performance, lean blowout limit, and combustion efficiency depend highly on the cavity-air injection mode. The injection slit exhibited excellent advantages in terms of ignition performance and lean blowout limit as compared to those of the injection hole. However, the injection hole showed prominent superiority in combustion efficiency as compared to that of the injection slit. The simulation results based on Reynolds-averaged Navier-Stokes (RANS) showed that the significant discrepancies in combustion performance may mainly attribute to the different flow characteristics of the two injection modes.