Experimental and numerical studies on hot streak transportation and attenuation in a 1.5-stage turbine

Research on multicomponent interactions in aero-engine design technology has gained significant attention. The presence of hot streak (HS) at the combustor exit is critical, as it affects the turbine aerodynamic performance and the heat transfer properties of the blades. This paper presents the design of a HS simulator for a 1.5-stage turbine rig, examining the transportation and attenuation mechanisms of HS at two circumferential clocking positions and temperature ratios. Numerical simulations were conducted using commonly employed two-equation turbulence models with varying turbulent Prandtl numbers (Pr-t). Results show that the choice of turbulence model and Pr-t value greatly influences the prediction precision of HS dissipation. The numerical method effectively predicts the HS attenuation levels at the exits of stator 1 (S1), rotor (R), and stator 2 (S2), while the radial migration of HS core is not well captured. The HS experiences an overall attenuation rate of 75%-85% in the 1.5-stage turbine. Both clocking positions and temperature ratios significantly impact the HS attenuation levels, although the extent of the effects varies across the three rows of blade. The HS core tends to migrate radially inward within the turbine stage, influenced by curvature, buoyancy, and secondary flow effects. The extent of these influences is still determined by the clocking positions, temperature ratios, and the specific blade rows.