Page 80 - IJAMD-1-3

International Journal of AI for
Materials and Design
Review of gas turbine blade failures by erosion

Table 9. Key research contributions highlighted in this article
Researcher (s) Focus area Methodology used Key findings
Hamed et al. 55 Erosion mechanisms in high-velocity CFD and experimental testing Identified critical erosion-prone zones
environments on turbine blades
Taherkhani et al. 56 Effect of particle size and velocity on FEM simulations and Showed particle velocity as the
erosion rates experimental studies dominant factor for erosion
Shin and Hamed 57 TBC erosion under high temperatures Taguchi method and SEM Highlighted porosity’s impact on
and velocities analysis erosion resistance
Branco et al. 58 Erosion of alumina-based coatings Particle impingement testing Porosity reduces erosion resistance by
weakening material
Zhu et al. 59 Thermal gradient effects on TBC Experimental tests and SEM Demonstrated spalling and fatigue
erosion imaging under combined conditions
Abbreviations: CFD: Computational fluid dynamics; FEM: Finite element method; SEM: Scanning electron microscopy; TBC: Thermal barrier coating.
gas turbine blades by integrating theories from multiple Erosion rate can be mathematically modeled to predict
disciplines, including fluid dynamics, material science, the amount of material loss over time. One of the early
and mechanical engineering. 60,61 The framework outlines models, Finnie’s equation, 65,68 posits that the erosion rate is
how various theories come together to explain the failure directly proportional to the kinetic energy of the particles.
mechanisms of turbine blades, focusing on how erosion It also emphasizes the importance of the impact angle,
compromises the structural integrity of the blades and where shallow angles tend to result in surface plowing
affects the overall operational efficiency. It also draws on (material deformation without removal), and higher angles
computational methods to model and predict failures, cause actual material loss. These models are essential for
helping to design more resilient blades and optimize understanding where and how fast erosion will occur on
maintenance schedules. 64,65 In addition, it incorporates turbine blades, especially in high-speed regions such as the
insights from material science to identify critical thresholds leading edge of the blades.
for wear and erosion resistance. These multidisciplinary The boundary layer theory offers insights into how
66
approaches ensure a comprehensive understanding of fluid flow behaves near the blade surface. It explains the
blade failure dynamics. The three main theoretical pillars development of turbulence close to the surface, which
are discussed in the following sub-sections.
affects how particles move and impinge on the blade. In
3.1. Erosion mechanism theories high-velocity gas flows, the turbulent boundary layer
can cause particles to move erratically, leading to more
The first pillar of the theoretical framework focuses on frequent and unpredictable particle impacts. 67,69 This
understanding how erosion mechanisms affect gas turbine theory helps explain why certain areas of a turbine blade
blades, particularly how solid particles suspended in airflow (e.g., leading edges and blade tips) experience more severe
impinge on the blade surfaces, leading to material removal erosion compared to smoother, laminar-flow regions.
and surface degradation. 62,66 These mechanisms are vital for
explaining the localized wear and tear observed on turbine Flow separation and particle rebound involves that the
blades during high-stress operational environments. interaction between fluid flow and blade surfaces often
leads to flow separation, especially at sharp edges or curved
Particle impact theory explains the interaction between
solid particles and the surface of turbine blades. Particles surfaces of the blades. When this occurs, particles rebound
suspended in the high-velocity gas stream collide with the off surfaces in chaotic patterns, increasing the likelihood of
high-energy impacts. Quintanar-Gago et al. showed that
68
turbine blades, leading to localized surface damage. 63,67 flow separation near the trailing edges can cause erosion
The rate and severity of erosion depend on the kinetic
energy of the particles, which is a function of their patterns that are more concentrated in certain zones,
velocity, size, mass, and the hardness of both the particle further exacerbating blade wear. Table 10 outlines the
influence of coating porosity on erosion resistance.
and the impacted material. Kumar et al. explored how
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high-velocity particles impact surfaces at various angles, This pillar is critical for understanding the physical
contributing to material loss through a process known forces behind erosion, allowing engineers to design blade
as SPE. They found that high-impact angles, particularly shapes and materials that can better resist particle impacts
those closer to 90 degrees, cause more severe erosion, as and prolong blade life. In the study of erosion-induced
the energy transfer during these collisions is maximized. damage in gas turbine blades, predicting the erosion

Volume 1 Issue 3 (2024) 74 doi: 10.36922/ijamd.5188