Compressor Cascade Angle Of Attack The Separation Vortex Characteristics

Vibration of the blade is a general and serious problem in the aero engine for a long time. Some analysis must be done previously for coupling analysis of flow and structure, such as characteristics of complex unsteady aerodynamic force, vortices shedding frequency, vibration mode and vibration characteristic of blade, etc. So, it is a significant job to investigate the unsteady flow in turbomachinery cascade especially the unsteady separating vortices in cascade which under a large positive incidence angle.Unsteady flow characteristics of cascade were analyzed in this thesis by means of numerical simulating the unsteady vortices characteristics in two dimensional cascade flow field. With the variety of inlet Mach number, the structures of separating shedding vortices were investigated in a compressor cascade which was under large positive incidence angle, meanwhile the vortices generating, shedding and dissipating were captured in the unsteady flow field. The potential effects of vortices to cascade performance were analyzed. The results reasonably indicate turbulent characteristics of the unsteady flow field in cascade passage. Data were obtained for further studies on the unsteady flow field in turbomachinery.Steady flow fields are also calculated to analyze flow field structure for the same cascade with different inlet Mach numbers and incidence angle. The numerical simulating results are satisfactory for practical design. Although the time-average parameters in unsteady flow field was essentially similar with that of in steady flow field, but separating vortices in the unsteady flow field play an important role in initiating periodical unsteady aerodynamic force on blade.Finally, the vibration modes of inlet guide vane and the rotor of firststage are calculated and analyzed by using the FEA software ANSYS, and the data for the resonate analysis and coupling analysis of flow and structure is provided.