Numerical Study of the Leakage Flow on a Novel Turbine Blade Tip

The traditional squealer tip of turbine blade performs good property in decreasing the leakage mass flow rate. The improvement of the aerodynamic performance for turbine blade tip is always continuing associated with the understanding of the leakage flow characteristic. Thus, a novel turbine blade tip, which is derived from the conventional squealer tip, is investigated numerically in this paper. The characteristic of the tip region flow field, the tip blade loading distribution and the tip leakage mass flow is analyzed in detail. The results show that, first some part of the tip region flows are forced to flow downstream along the guided groove formed by the recessed pressure side rim, which contributes to the preventing of the leakage mass flow and the descending of leakage loss as well. Besides, the blade loading of the novel geometry is raised than the traditional squealer tip, which reveals that the mass flow rate of the working fluid is increased. Third, the leakage mass flow is reduced so that the efficiency is increased. The CFD analysis predicts that, the novel squealer tip case shows 30% less leakage mass flow and a 0.11% total isentropic efficiency increase for a single rotor compared to the baseline squealer tip case. (C) 2015 The Authors. Published by Elsevier Ltd.