Computations on the flow characteristics and sealing performance of a stator well cavity for the second stage in gas turbine

•We study the ingestion of a new stator-well cavity.•The more realistic model of two stage turbine with stator well is established.•The effects of sealing flow rate, annulus pressure ratio and rotation speed have been studied.•The flow structure, distribution of annulus pressure ratio and sealing effectiveness are discussed in detail. In this paper, a numerical study is conducted to determine the effect of sealing flow rate, annulus pressure ratio as well as rotation speed on the flow dynamics and sealing performance for a rim cavity. The computational model is performed for a two-stage mainstream cascade passage with a stator-well cavity which consists of a pre-swirl cavity and two rim cavities beneath second vanes. The Reynolds-averaged Navier–Stokes equations, coupled with Shear Stress Transport turbulence model, and a scalar equation are solved. The results obtained in this paper indicate that the downstream rim cavity shows better sealing performance than that of upstream rim cavity. The flow field in the upstream rim cavity is sensitive to the sealing flow rate and rotation speed but is insensitive to the annulus pressure ratio. However, the sealing flow rate, rotation speed and annulus pressure ratio has negligible effect on the flow field within the downstream rim cavity. With an increase in sealing flow rate or rotation speed, the sealing effectiveness increases. Nevertheless, increasing annulus pressure ratio contributes to the hot gas ingestion. Moreover, the pressure distribution in the mainstream annulus and the variation of sealing effectiveness on the stator and rotor wall in upstream and downstream rim cavity with radius is discussed in detail.