Flow Analysis of 1.5 Stage Compressor with Variable-camber Inlet Guide Vanes

Installing the variable-camber inlet guide vanes (VIGV) on aero-engine can both adjust inlet flow of next bladerow and change the pre-spin. In this paper, flow field is numerically predicted at different curvatures of the VIGV. The rotational speed set at 63% of design rotational speed, turbulence model is Spalart - Allmaras, and central difference scheme is chosen as the discrete scheme. Nonlinear harmonic method is adopted to analyzing how the unsteady flow and wake affect next blade row at different time step when curvatures of VIGV set to be 0 and-5. The effect of wake on relative velocity and outlet flow angle at 0.25T, 0.5T, 0.75T and 1T from 10% to 90% height were analyzed. The results show that wake of rotor affects flow above 50% height, but it has less effect on flow near the hub. The wakes of VIGV have less effect on rotor, but the wake of rotors has more effect on next bladerow. Wake affects less flow of next bladerow when VIGV is adjusted to 0 degrees. Overall, the velocity of -5 degrees VIGV is higher than that of 0 degrees VIGV in rotor passage, and total pressure ratio of -5 degrees VIGV is higher than that of 0 degrees VIGV. The scale of 0 degrees VIGV vortex is bigger than that of -5 degrees VIGV in first stators when the compressor operates near the surge line. Stability range of -5 degrees VIGV is wider than that of 0 degrees VIGV. The performance of the -5 degrees VIGV is better than that of 0 degrees VIGV when operating condition is close to surge line. On the whole, by installing VIGV the performance of aero-engine can be improved, which provides guidance for compressor designers.