Water Film Formation and Performance Effect on Compressor Stage in Water Injection Process

Abstract

Abstract In this study, the thickness of water film, which is frequently formed on compressor blade surface, was investigated. Simultaneously, its movement and extra torque demand were provided by a simulation model of the code. Having taken into account the transformation in blade’s profile and the thickness feature of the films, the working medium characteristic transformation in compressor stage was analyzed. In addition, formation, development and movement of the water film on a compressor stage were simulated by using unsteady numerical methods in various water injected conditions. Movement characteristics of water droplets in cascade were investigated to understand the flow mechanisms responsible for water film formation process. The forming and the tearing process of water films, which formed on the blade surface, were analyzed at different injection conditions. In consideration of the “Scoop effect” in actual situation, the maximum quantity of injected water can reach 12 %. Results indicated that continuity and region of the film would be developed with the increment of droplet size and injection rate. It was also found that water film’s tearing process brought about flow losses near blade surface due to the increment of surface roughness.