Evaluation of Interstage Water Injection Effect on Compressor and Engine Performance

Abstract

The present paper examines the effect of water injection at the compressor inlet or between stages, on its operation. A wet compression model coupled with an engine performance model is used. The wet compression model produces the compressor performance map when water is present and consists of a one-dimensional stage stacking model, coupled with a droplet evaporation model. The effect of water injection on overall performance and individual stage operation is examined. The map-generation procedure is embedded in an engine performance model and a study of water injection effect on overall engine performance is undertaken. The possibility to evaluate the effect on various parameters such as power, thermal efficiency, surge margin, as well as the progression of droplets through the stages is demonstrated. The results indicate that water injection causes significant stage rematching, leading the compressor toward stall and that the performance enhancement is greater as the injection point moves towards compressor inlet.