PSI - Issue 17

Available online at www.sciencedirect.com Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2019) 000 – 000 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2019) 000 – 000

www.elsevier.com/locate/procedia www.elsevier.com/locate/procedia

ScienceDirect

Procedia Structural Integrity 17 (2019) 532–538

ICSI 2019 The 3rd International Conference on Structural Integrity Microscopic examination of a fan blade supporting system premature fractured D.G. Papageorgiou a,b , H. Bravos a , C. Medrea a,* a Department of Mechanical Engineering, University of West Attica, 250 Thivon & Petrou Ralli Str.,12244, Egaleo, Greece b Stassinopoulos-Uddeholm, Steel Trading S. A., 20 Athinon Str. 18540 Piraeus, Greece A local company generates electricity via combined cycle power plant using natural gas. After the steam turbine, the in-line working fluid needs to be liquefied by a condenser. A water cooling system which is comprised of a fan cooling tower is used. The tower is consisted of series of cooling fans. The fans are comprised of blades which are supported onto a hub by “U” shaped holders. These pieces frequently brake down disturbing the normal operation of the unit. The paper refers to the microscopic examination of the failed parts. Historical data was collected, the pieces were macroscopic examined, hardness measurements were carried out and chemical analysis was performed. The study involved a detailed examination of the microstructures and fracture morphologies of the specimens derived from the failed parts. Conclusions are presented related to the fracture mechanism and the type of fractures respectively. All of the blade holders on this analysis were totally break by low cycle fatigue. Usages of impropriate material, as well as design deficiency of the holders, are considered to be the main causes for the failure. ICSI 2019 The 3rd International Conference on Structural Integrity Microscopic examination of a fan blade supporting system premature fractured D.G. Papageorgiou a,b , H. Bravos a , C. Medrea a,* a Department of Mechanical Engineering, University of West Attica, 250 Thivon & Petrou R lli Str.,12244, Egaleo, Greece b Stassinopoulos-Uddeholm, Steel Trading S. A., 20 Athinon Str. 18540 Piraeus, Greece Abstract A local company generates el ctricit via combined cycle power plant using natural gas. After the steam turbine, the in-line working fluid needs to be liquefied by a condenser. A water cooling system which is comprised of a fan cooling tower i used. The tower is consist d of series of cooling fa s. The fans ar comprised of blades w ich are supported onto a hub by “U” shaped holders. These pieces frequently brake down disturbing the normal operation of the unit. The paper refers to the microscopic examination f the failed parts. Historical data was collected, the pieces were macroscopic ex mi ed, hardness measurements were carried out and chemical analysis was performed. T study involved a detailed examinatio of the microstructures and fracture orphologies of the specimens derived from the faile parts. Conclusions are presented related to the fractur mechanism and the type of fractures respectively. All of the blade holders on this analy is were totally break by low cycl f tigue. Usages of impropriate material, as well as design deficiency of the holders, are considered to be the main causes for the failure. Abstract

© 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ICSI 2019 organizers. © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ICSI 2019 organizers. © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ICSI 2019 organizers.

Keywords: water cooling system; cooling fans; supporting system; fan blade holders; ‘U” bold. Keywords: water cooling system; cooling fans; supporting system; fan blade holders; ‘U” bold.

1. Introduction 1. Introduction

A combined cycle power plant comprises of a combination of gas and steam power production technology; the gas turbine produces power directed to a generator and hot exhaust gases produce steam directed to a turbine. The need of economic and energy saving by efficient processing of raw materials brought combined cycle power plant on A combined cycle power plant comprises of a combination of gas and steam power production technology; the gas turbine produces power directed to a generator and hot exhaust gases produce stea directed to a turbine. The need of economic and energy saving by efficient processing of raw materials brought combined cycle power plant on

2452-3216 © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ICSI 2019 organizers. 2452-3216 © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ICSI 2019 organizers. * Carmen Medrea. Tel.: +302107651041; fax: +302105381165. E-mail address: cmedrea@uniwa.gr * Carmen Medrea. Tel.: +302107651041; fax: +302105381165. E-mail address: cmedrea@uniwa.gr

2452-3216  2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ICSI 2019 organizers. 10.1016/j.prostr.2019.08.071