Numerical simulation on effect of ingress for counter-rotating turbine discs

摘要

In this paper the three dimensional, unsteady Navier-Stokes equations are solved to simulate the hot gas ingress through the rim seals of a specialized counter-rotor turbine disc with the annulus flow. The mechanic of hot gas ingress for a counter-rotating system is researched. Also, the influence factors on the seal efficiency are investigated, especially of the rim seal geometry and work condition of the turbine. The following is part of the results and conclusion. Results of the numerical simulations show that front blades have more significant influence than rear blades on pressure distribution in the annulus. At the same time, the interaction between front and rear blades is the convergence and separation of the high pressure regions is analysed to illuminate the unsteady flow for the counter-rotating turbine system. Last, a mathematic model for predicting the minimum seal flow is obtained, and the minimum seal flow is related with the ratio of the clearances and the rotating Reynolds number.