NUMERICAL STUDY OF WET COMPRESSION USING METHANOL INJECTION IN AXIAL COMPRESSOR

A numerical model has been developed to study the impact of wet compression on the performance of three stages axial compressors. The CFD code, ``FLUENT{''} was used to solve the governing equations in three dimensional, unsteady, turbulent flow scheme. Considering their advantages as volatile, non-corrosive, less erosive and renewable, Methanol droplets were considered for wet compression. They are introduced as a dispersed phase and are tracked in a Lagrangian frame. The model accounts for droplet-flow, droplet-droplet, and droplet-wall interactions. The compressor performance is analyzed in terms of variation of air properties, characteristics of the operating point, and consumed power, due to wet compression. Parametric study has been conducted to find out the impact of different parameters on the performance of the compressor. These include the effect of; injection ratio, droplet size, and droplets agglomerations. It has been found that increasing the injection ratio reduces the temperature in both axial and radial directions. This in turn reduces the compressor specific power consumption. On the other hand, increasing the injected droplet size has an adverse effect on droplet evaporation rate and hence on specific power consumption. Droplets agglomerations tend to increase droplets sizes especially at rear stages of the compressor. This is also attributed to the omission of the smaller droplet due to early evaporation. Effect of agglomeration is emphasized as a result of higher loading ratio.