Numerical investigation of an aggressive s-shaped compressor transition duct with boundary layer suction

Abstract

Aggressive s-shaped compressor transition ducts are important components in the connection between upstream boosters and downstream high-pressure compressors. The flow path is an s-shaped channel with struts and a large radial drop length ratio, which breaks through the limitations of traditional design and has a large aerodynamic loss. Therefore, this paper considers an aggressive s-shaped compressor transition duct in a geared turbofan engine and creatively proposes a method for controlling the flow separation through boundary layer suction. The results show that hub suction reduces the losses of the aggressive s-shape transition duct. As the mass flow rate of hub suction increases, the total pressure loss coefficient decreases and the rate of reduction in the total pressure loss slows down. Combined boundary layer suction reduces the total pressure loss to a greater extent. On the premise that the location of blade suction remains unchanged, the optimal location for the circumferential slot of hub suction is at 20% of the axial chord length of the strut, whereby the total pressure loss coefficient decreases by about 30% compared with the case of no suction. When the mass flow rate of suction is fixed at 3% of the inlet mass flow rate, a distribution of 0.5% from blade suction and 2.5% from hub suction reduces the total pressure loss by 1.6% compared with the case where all 3% comes from hub suction. The distribution of the mass flow rate for combined boundary layer suction has an optimal ratio.