A Correction Method for the Effects of Reynolds Number, Roughness, and Tip Clearance on Geometric Scaling of Axial Compressors

The geometric scaling method is often used in the design and development of axial compressors to reduce high costs. However, Reynolds number, surface roughness, and tip clearance are often difficult to satisfy all the similarity criteria, which breaks the similarity between the Prototype and the Model compressor. This study utilized a 1.5-stage axial compressor as the Prototype to investigate the effects of Reynolds number, surface roughness, and tip clearance on the geometric scaling process. First, the 0.5 scale Model compressor was simulated using RANS method with the scalable wall function. A test facility was constructed for the 0.5 scale Model compressor, and experiments of varying surface roughness and tip clearance were carried out to verify the reliability of the numerical method. Then, the Prototype and Models with scaling factors of 0.4 and 0.33 were simulated using the same numerical method. By analyzing the numerical results of the Prototype and the three Models, a novel correction method for the deviation between the performance of the Prototype and the Model was proposed. This method can be used to correct the deviation of compressors' performance curves caused by the change in Reynolds number, surface roughness, and tip clearance during the geometric scaling process. Meanwhile, both numerical and experimental results were used to validate the accuracy and the universal applicability of the method.