Numerical Prediction of The Performance Recovery of an Axial Compressor by Inlet-Air-Injection Technique During The Unstable Operations

The effects of the inlet air-injection on aerodynamic behavior and the characteristics of anaxial compressor were numerically investigated. The operation curve was numerically capturedat the design operation region of a specified test compressor with no air -injection. Thecomputed result s showed good agreements with those obtained from the experiments, tovalidate the unsteady two-dimensional finite-volume solver which was developed based on VanLeers flux splitting algorithm in conjunction with TVD limiters and the K- E turbulence model.At the second step, to show the improvement of the operation curve during the air injection, theoperating points were adjusted to the unstable values, and the aerodynamic unstable streamlinesand consequently the performance reduction were revealed apparently . Afterwards, the requiredair-injection at the inlet was imposed numerically, and all unstable flow pattern s were removedwith a significant recovery of the performance, to present a numerical explanation of the air injection technique.