Investigation into the Effect of Leading-Edge Contouring on Aero-Thermal Performance in Blade Endwall Region

The aero-thermal performance in a rotor blade endwall region with leading-edge contouring was numerically investigated with the computational fluid dynamics method. The secondary flow structures, aerodynamic loss and heat transfer characteristics near the endwall were analyzed with three structures of leading-edge fillet contouring, i.e. no leading-edge fillet, linear profiling fillet, and parabolic profiling fillet. The roles of horse-shoe and passage vortices in the flow and heat transfer performance were compared between the cases with and without fillet. The results show that the leading-edge fillet contouring is able to reduce the wall shear stress and yaw angle, and reduce scale and intensity of horse-shoe vortices near the leading edge, but it has a slight suppression effect on the development of passage vortex downstream of the leading edge. Moreover, the leading-edge fillet tends to reduce the transverse flow in the endwall region, resulting in a decreased total pressure loss in the rear part of blade passage. For the parabolic profiling fillet case, the turbulence kinetic energy and horse-shoe vortex scale in the corner area of leading edge are slightly smaller than those of linear profiling fillet case. For all fillet contouring cases, the pitch-averaged Nusselt number downstream of the leading edge is decreased along the streamwise direction. Compared with no leading-edge fillet case, the maximum decrease of pitch-averaged Nusselt number on blade endwall near leading edge reaches about 40%, but it is only reduced by 8% at the rear part of blade passage. At the rear part of blade passage, the pitch-averaged Nusselt number on blade endwall for the parabolic profiling fillet case is slightly lower than that of linear profiling fillet case. © 2022, Editorial Office of Journal of Xi'an Jiaotong University. All right reserved.