Experimental and numerical study on the influence of pneumatic parameters on the flow structure in trapped vortex combustor

Abstract

Flow field of combustors have been commonly used to help understand the combustion characteristics. In this study, the experimental and numerical investigation was carried out combined to study the effect of pneumatic parameters, such as the main stream Mach number, pressure ratio, and temperature, on the flow structure in a trapped vortex combustor This study aimed to investigate the influence of pneumatic parameters on the vortex center position and area of primary and secondary vortices in the cavity, and also study the distribution of axial and radial velocity in the cavity obtained by changing the inlet airflow temperature. The flow fields in the combustor cavity with the variation of main stream Mach number and pressure ratio were obtained by using Particle Image Velocimetry The results show that, a double-vortex pattern can be generated and tightly locked inside the cavity. Furthermore, the flow structure is significantly influenced by pressure ratio (r_p = 0.97–1.07) instead of mainstream Mach number (Ma = 0.13–0.17). Under the same Mach number, the location of vortex center in the main stream plane is moved with the appearance of the temperature gradient. Meanwhile, the velocity profiles indicate that the axial velocity is reduced as the temperature increase. This study provides a design guideline for combustion with the main stream and second stream, and also offers important reference value for the analysis of combustion performance in cavity.