Research on the Low-speed Similarity Principles for Compressor Stator Airfoils

Some analyses of low-speed similarity design principles have been done for stator airfoils. It was proposed that the outlet flow angle should be kept unchanged for high-to-low speed transformation. Based on the design principles and a one-dimensional isentropic hypothesis, a constrained model of throat width for stator airfoils was derived, and the method of calculating geometry design parameters of low-speed airfoil was presented. According to the analysis results, a set of low-speed similarity transformation of high-speed stator CDA airfoil was carried out. The numerical results showed that the incidence-loss characteristics and incidence-deviation-angle characteristics had a good agreement for high and low speed airfoils. What's more, the relative error of throat width is small between the actual value and the value calculated by the throat constraint model. Therefore, the adjustment of parameters such as maximum thickness of low-speed blade could be guided by the throat constraint model, which could reduce the iterations of design low-speed airfoils.