Experimental investigation on the performance characteristics of a 2D trapped vortex combustor

Abstract

The performance characteristics of a 2D trapped vortex combustor (TVC) are investigated experimentally in terms of the exhaust gas emission level, combustion efficiency, and the exit temperature uniformity. The present study reveals that the EICO and EIUHC emission levels are sensitive to mainstream Reynolds number ( Rems), cavity equivalence ratio ( Øc), and primary air velocity ( Vp). Besides this, mainstream premixing also has significant impact on the emitted pollutant level. Moreover, the NOx emission level can be reduced to very low levels (<2.6 ppm), which will be difficult to achieve in conventional combustors. Combustion efficiency calculated from these emission results indicates that it is influenced by cavity equivalence ratio and primary air velocity. For particular Rems, Vp, and Øc, combustion efficiency closer to 99% could be achieved for the merged flame cases, especially at higher primary air velocity. On the other hand, for a particular value of Vp, an increase in Rems tends to quench the cavity flame leading to reduction in combustion efficiency. This study also indicates that flame merging helps in efficient utilization of fuel and thus leading to better combustion efficiency. Besides this, the conditions for achieving lower pattern factor ( PF) are also brought out from exit temperature measurements. Pattern factor as low as 0.1 could be achieved particularly at higher Vp cases. It can be noted that this value is lower than that of the PF value of swirl combustors (0.2–0.4). Based on the present investigations, it can be concluded that TVC is a viable technology to be considered for future gas turbine application.