Aerodynamic performance response due to stagger angle variation in an axial supersonic through-flow fan blade

To enable a broader operational speed range in axial supersonic through-flow fans, this study investigates the effects of stagger angle variation (Δγ) using an adjustable cascade configuration. A comprehensive numerical study, covering a wide range of inlet Mach numbers from subsonic to supersonic regimes, was conducted to assess how Δγ affects aerodynamic performance and flow structure. A framework for entropy generation analysis based on dissipative sub terms was proposed, quantifying aerodynamic losses and elucidating potential flow physics. The results show that at design incidence, Δγ has a pronounced effect on the loss coefficient (ω), static pressure ratio (π), and flow turning angle (zw), particularly under transonic inflow conditions, with changes relative to Δγ = 0° reaching 168.2%, 216.9%, and 115.4%, respectively. Under subsonic conditions, the enhanced streamwise adverse pressure gradient at higher Δγ thickens the boundary layer, which elevates wall-normal shear. This makes (∂w/∂y)2 the dominant dissipation mechanism governing loss behavior. In supersonic flows, the loss increase is mainly driven by intensified oblique shock, which enhance streamwise shear and entropy generation. In contrast, the contribution of wall-normal shear dissipation remains relatively insensitive to Δγ variations. At off-design incidence, critical Δγ thresholds are identified at which losses surge significantly. For M = 0.60 and i = −3°, reducing Δγ from −4° to −8° induces a quasi-normal shock within the passage. Similarly, for M = 1.00 and unique incidence, as the Δγ increases from 4° to 8°, the trailing-edge shock transforms into a λ shock. Both of these shock evolutions cause increased shock and viscous losses.