Effects of Reynolds number on the flow field in a low-pressure turbine with incoming wakes

In order to further understand the effects of the Reynolds number on the flow field within a low-pressure turbine with incoming wakes, the transition SST turbulence model was employed for numerical simulation under four Reynolds number conditions ranging from 0.6x105 to 3.0x105. The numerical results showed that the boundary layer separation at the rear part of the suction surface was prone to occur in the condition of low Reynolds number (Re2th = 0.6x105), and the separation bubble was semi-open and semi-closed. The separation bubble impedes the development of the passage vortex and wall vortex towards mid-span region. When the Reynolds number exceeds 1.0x105, boundary layer separation does not occur. The influence of Reynolds number on the total pressure loss coefficient is primarily evident on the suction surface side, and the growth rate of total pressure loss coefficient first increases and then decreases along the streamwise direction. As the Reynolds number increases from 0.6x105 to 3.0x105, the peak point location of total pressure loss decreases by approximately 12 %. The influence of Reynolds number on corner vortex and wall vortex is relatively more sensitive compared to that of passage vortex.