TY - GEN

T1 - Blade Vibration Measurements in a Multi-Stage Axial Turbine with Geometric Variations

AU - Hauptmann, Thomas

AU - Seume, Joerg R.

N1 - Funding Information: As described in Rupp (2000)1 the maintenance, repair, and overhaul process of jet engines, also referred to as regeneration, is of great interest since 8% of the operating cost of an airplane is due to engine overhaul. The main cost factor of the overhaul are the blades, which account for approximately 50% of the cost. This is mainly incurred by the replacement of worn blades from the high-pressure turbine. They are one of the most highly-loaded parts and are subject to substantial wear. For this reason, the Collaborative Research Center (CRC) 871 “Regeneration of Complex Capital Goods”, funded by the German National Science Foundation (DFG), aims to develop the scientific basis for the overhaul of jet engines. The main aim is to save as many of the worn components as possible, as presented by Aschenbruck et al. (2014).2

PY - 2018/1/7

Y1 - 2018/1/7

N2 - In jet engines, blade repair is often more economical than the replacement of damaged blades with spare parts. Besides such a regeneration of turbine blades, blade rubbing and erosion also lead to a deviation from the original blade geometry. Typical regeneration and wear-specific geometric variations of turbine blades are applied to turbine vanes and blades of a five-stage axial air turbine. These geometric variations introduce non-uniform flow conditions, which in turn lead to an excitation of the blades. The vibration amplitudes of the turbine blades are measured with an optical blade tip-timing system. Additionally, an optical tip clearance probe is implemented to verify the accurately measure the tip clearance size simultaneously with the tip-timing measurements. The geometric variations lead to a change of the aerodynamic excitation, which results in a remarkable change of the vibration amplitude determined by the blade tip-timing system. This variation is shown to dependent on the geometric variations and the investigated operating points.

AB - In jet engines, blade repair is often more economical than the replacement of damaged blades with spare parts. Besides such a regeneration of turbine blades, blade rubbing and erosion also lead to a deviation from the original blade geometry. Typical regeneration and wear-specific geometric variations of turbine blades are applied to turbine vanes and blades of a five-stage axial air turbine. These geometric variations introduce non-uniform flow conditions, which in turn lead to an excitation of the blades. The vibration amplitudes of the turbine blades are measured with an optical blade tip-timing system. Additionally, an optical tip clearance probe is implemented to verify the accurately measure the tip clearance size simultaneously with the tip-timing measurements. The geometric variations lead to a change of the aerodynamic excitation, which results in a remarkable change of the vibration amplitude determined by the blade tip-timing system. This variation is shown to dependent on the geometric variations and the investigated operating points.

UR - http://www.scopus.com/inward/record.url?scp=85141619665&partnerID=8YFLogxK

U2 - 10.2514/6.2018-0952

DO - 10.2514/6.2018-0952

M3 - Conference contribution

SN - 9781624105326

T3 - AIAA/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference, 2018

BT - AIAA/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials

PB - American Institute of Aeronautics and Astronautics Inc. (AIAA)

T2 - AIAA/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference, 2018

Y2 - 8 January 2018 through 12 January 2018

ER -