Under actual operating conditions of gas turbine, centrifugal and thermal growth of disc in radial direction result in dislocation of inflow boundary at the disc mid-radius height, and a radial step of platform at high radius height. In this paper, flow and heat transfer characteristics in dislocated rim seal region are analyzed by the conjugate and thermal mechanical numerical methods.
The calculated radial growths of turbine discs reach approximately 14–20 % of turbine platform structure thickness. Dislocation of rim seal structure directly affects the flow characteristic of externally-induced (EI) ingress and rotationally-induced (RI) ingress, and aggravates overheat of stator disc due to induced hot gas ingestion, further affects the loss of mixture of mainstream gas and cooling sealant air flow in rim-seal and wheelspace regions. Radial step between rotor and stator platforms exacerbates the area and depth of hot gas ingestion in seal clearance, along with a 2–7 % decrease in seal efficiency.