CFD Validation of Tip Clearance Flows in an Axial Compressor

When designing a compressor it is desirable to keep the development cost low while ensuring that the compressor meets the required performance. The typical strategy to dene a complete 3D compressor geometry is to use CFD models in combination with an optimization tool. The general problem with this is that the optimization requires many CFD evaluations and the more physically correct the CFD model is, the more computationally costly it becomes. Therefore the complexity of the CFD model at this stage of the design process must be kept relatively low in order to meet the targeted development cost and time. When the most promising designs have been identified, a more physically correct but more computationally heavy model is used to verify the compressor performance. Up to the present however, there has been no CFD model capable of fully capture the flow physics in compressors while being computationally cheap enough to be used for design. A particular challenge in this is to accurately predict the impact of the rotor tip clearance gap.In this thesis the aim has been to validate both simplied and detailed CFD models with experimental data on a low-speed axial compressor researched within the LEMCOTEC project. The main focus has been to determine the models ability to predict the compressor characteristics and in particular to capture the eects of the tip clearance. The results show that the overall compressor performance is best predicted with the CFD models that does not resolve the tip clearance gap. The models resolving the tip clearance gap seems to exaggerate its impact, more so with the simplified model.Validerat; 20160701 (global_studentproject_submitter