Effect of strut length on combustion performance of a trapped vortex combustor

Experimental studies with four different strut setups are conducted to investigate the effect of strut length on combustion performance of a trapped vortex combustor (TVC). The experimental results indicate that ignition, lean blowout (LBO) and combustion efficiency depend to a great extent upon the length of the strut. The longer struts show prominent advantages in terms of ignition and LBO, whereas the shorter ones perform rather poorly. Interestingly, the combustion efficiency achieved by the shorter struts is higher than the longer ones. Furthermore, RANS based simulations are also performed to explain the experimental results. From the detailed numerical simulations, it can be inferred that the poor ignition performance and LBO limits of the shorter struts are mainly caused by the great amount of mainstream air entrained into the cavity. And the higher combustion efficiency achieved by the shorter struts is mainly attributed to much more wake regions formed behind the struts.