Noise Investigation of Hot and Cold Flow Mixing in a Lobed Mixer of a High Bypass Ratio Turbofan Engine by FW-H method

Today, lobed mixers are recognized as an effective means in reducing noise in turbofan engines. In this study, the effect of mixing hot and cold flow in a lobed mixer on noise reduction is surveyed and simulated. Navier Stokes equations are considered to be three-dimensional, compressible, unsteady, and turbulence. The k-ω SST equation has been used to solve the turbulent flow, and the Ffowcs Williams Hawkings (FW-H) model has been used to investigate the sound pressure level. The results of this study show that the amount of sound pressure level(SPL) decreases as the output current moves away from the nozzle. Also, the frequency range between 80 and 10,000 Hz is considered. At 80 Hz, there is the highest sound pressure level, and as the frequency increases, the sound pressure level decreases. The results show that the sound pressure level at frequencies below 1000 Hz is higher than other frequency ranges.