Analysis and Numerical Simulation the Effect of Penetration of Lobe on Flow Mixing in Lobed Mixer

Mixer is one of the Main components of turbofan engine, which is used to mix the cold air flow from bypass and the hot airflow form engine core. The one of the factors affecting the mixing rate is the depth of mixer lobes. Also comparing the depth of penetration of lobes and its effect on mixing flows with simulation has been investigated. In this type of turbofan engines, the Mach number range is between 0.3 and 0.8. In this study, the Navier-Stokes equations are considered as three-dimensional and steady and flow is considered as compressible and turbulence. The standard k-e model with wall function is used to simulate flow. First, the numerical simulation method is validated, then phenomenon of mixing of flows in lobed mixer is investigated under the effect of lobe depth. The results show that variations of lobe depth strongly effect the secondary flow rate, the circulation power of the flow, and pressure in the lobes. With increasing depth of lobe, the flow velocities is decreased and the lateral and span wise components of velocity increase. Finally, it can be concluded that the effectiveness of mixing in high depth mixer is 70% in the middle of the lobes and in the low depth mixer is 47% in the middle of lobe. Compared to the two types of Lobes, by quadrupling the depth of lobes in high-depth lobes, about 49% the total effect of mixing in high-depth lobes is greater. Also, it can be concluded that the effect of mixing, the rate of secondary flow and the amount of turbulent kinetic energy in the high depth lobed mixer is higher than the low depth and maximum of mixing is in middle of lobe.