Analysis and Testing of the Vuicain 2 Lox Turbine Blades for Prediction of High Cycle Fatigue Life

This paper describes the design approach used for high cycle fatigue(HCF) life predictions of the turbine blades of the liquid oxygen(LOX) turbopump for the Vulcain 2 engine, powering the main cryogenic stage of the Ariane 5 launcher. The Vulcain 2 LOX turbine is a two-staged supersonic/transonic impulse type turbine, working in a gas generator cycle, see Figure 1. At 12660 rpm, turbine power output is 5130 kW using a pressure ratio of 12.0 from manifold inlet to diffuser outlet. Rotor with bearings is arranged as an overhang turbine designed to work at subcritical speeds. The rotor concept is shrouded blades connected to the disk with firtree attachments. The development of the Vulcain 2 engine was started in 1995 and the first flight is scheduled for late 2001. Figure 1 Vulcain 2 TPO, pump and turbine arrangement The main activities performed are: • Unsteady force predictions using CFD tools and measurements in air test rig. • Damping evaluation of the blades in air rig using different configurations of dampers. • Alternating stress predictions of the blades using FE analysis and strain measurements at test. • HCF life evaluation. The objective, using this method, has been to establish a more accurate prediction of the dynamic response of the turbine blades, resulting in a safer design prediction Copyright © American Institute of Aeronautics and Astronautics, Inc., 2000. All rights reserved. 1 American Institute of Aeronautics and Astronautics (c)2000 American Institute of Aeronautics & Astronautics or Published with Permission of Author(s) and/or Author(s)' Sponsoring Organization. regarding high cycle fatigue failure.