Failure analysis of a fan blade holding assemblement, installed on the cooling tower of a power plant. (September 2021)

• Record Type: Journal Article
• Authors: Medrea, C.; Papageorgiou, D.G.; Bravos, H.; Chicinaş, I.
• Is Part Of: Engineering failure analysis. Volume 127(2021)
• Publication Date: 2021-09
• Subjects: Cooling tower -- U-bolt fan blade holder -- Low cycle fatigue fracture -- Low alloy structural steel -- Austenitic stainless steel; System failures (Engineering) -- Periodicals; Fracture mechanics -- Periodicals; Reliability (Engineering) -- Periodicals; Pannes -- Périodiques; Rupture, Mécanique de la -- Périodiques; Fiabilité -- Périodiques; Fracture mechanics; Reliability (Engineering); System failures (Engineering); Periodicals; Electronic journals; 620.112
• DOI: 10.1016/j.engfailanal.2021.105505
• Languages: English
• ISSNs: 1350-6307

Abstract

Highlights: The failure of U-shaped holders, part of fan blades supporting system, was analyzed. All pieces were total cracked by fatigue. Inappropriate material selection and design deficiency are the main causes of failure. Technical solutions were proposed in order to avoid similar failures. Abstract: Cooling towers are important heat exchangers in power generation industry comprising of centrifugal fans which are used for cooling purposes. The present research investigates the failure occurred on the fan blade supporting system, installed on the cooling tower of a power plant. Τhe tower is consisted of twenty fans. Their blades are supported onto a hub by "U" shaped holders. These specific fitments frequently undergo damages increasing plant downtimes as well as the risk of accidents. The study comprises of historical data recording, macroscopic examination, hardness measurements and chemical analysis of three failed components. Moreover, the microstructure and fracture surface morphology of failed components are thoroughly analyzed. Conclusions are presented regarding the failure mechanism and its propagation mode. Holders were totally break by low cycle fatigue. Improper material selection and poor design are mainly responsible for the repeated damage. Practical recommendations were delivered to avoid similar failures.