Analysis of transonic tandem rotor and matching characteristic of forward and aft blades

With transonic tandem rotor technology, fan stage design is accomplished to produce total pressure ratio of 2.25 and responding loading coefficient of 0.55 at corrected tip speed of 381 m/s. Based on the simulation results, the distinctive matching characteristic between forward blades (FB) and aft blades (AB) is analyzed, as well as the reason for its difference from conventional multistage compressor. Analytic correlation of aerodynamic parameter between the FB and AB is deduced and testified further, which provides a mathematic and physical model to elementary design for tandem rotor in conventional compressor design system. The result indicates that while the operating point is moving from choking to near stall condition, the characteristic of FB is identical with conventional rotor, whereas the total temperature rise and total pressure ratio of AB are declining in certain analytic rules. The model in this paper is competent to predict the characteristic of AB.