Investigation and Modeling of Two Phase Flow through a Compressor Stage: Analysis of Film Breakup

For stationary gas turbines, the injection of water sprays into the compressor inlet is used to rapidly increase the power output. To fully utilize this technique a comprehensive understanding of the underlying phenomena is needed. An in-house CFD program was developed at Institute of Aerospace Thermodynamics (ITLR) Stuttgart which was validated on the transonic wind tunnel at Helmut Schmidt University (HSU) Hamburg. The present paper focuses on the water film on the blades formed by water deposition of impinged droplets. Experimental results using a reflective shadowgraphy method reveal the wall film pattern on the blade without disturbing the flow. A numerical model is presented predicting the position of film breakup based on linear stability analysis. The film breakup position is analyzed for three different water loads showing an almost constant position for the onset of film breakup in the experiments which is well captured by the numerical model.