Investigating the Effect of Casing Injection Parameters on Transonic Axial Compressor Performance

One of the factors that can cause a reduction in the efficiency and performance of axial compressors is the tip leakage flow of the compressor blade. In the first, the compressor’s performance curve is compared with experimental results obtained under the condition of no air injection, and a statistically significant agreement is observed. The present study investigates the impact of various parameters, including flow rate, diameter, angle, and injection location, on the compressor’s performance curve and flow structure, taking into account the injection of air into a passage. The results indicate that the compressor’s stall margin and stable range extension are at their maximum values at a specific scale of each of the aforementioned parameters. Any deviation from this scale, either by reducing or increasing the injection parameters, leads to a reduction in the above characteristics. Although the presence of injection leads to an increase in the total pressure ratio in all injection states compared to the state without injection, the adiabatic efficiency at similar mass flow rates exhibits no significant change. The results also indicate that flow injection in the most suitable state increases the stall margin amount by 27% and the stable range extension of the compressor by 192.