Numerical simulation of aerodynamic performance for multi-channel diffuser in aero-engine combustor

To meet the performance and structural requirements of modern aero-engine combustors, including low pollutant emissions, low total pressure loss, and structural compactness, the effects of key design and operating parameters on the performance of a multi-channel diffuser were analyzed using CFD. The effects of area ratio, relative expansion gap, and inlet Mach number on the total pressure loss were examined, and the results were compared with relevant data in the literature. It is shown that the area ratio and the relative sudden expansion gap significantly affect the aerodynamic performance of diffuser. When the relative sudden expansion gap is 1.5, as the area ratio increases from 1.4 to 1.8, significant vortex-like changes occur at the outlet section of the diffuser, resulting in an increase in flow loss, with the total pressure loss change rate being approximately 30%. As the Mach number increases, the total pressure loss keeps rising, from 1.20% under the condition of 0.15 Mach number to 13.85% under the condition of 0.50 Mach number, and the total pressure loss increases linearly with the square of the inlet Mach number.