Page 85 - IJAMD-1-3

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

risk, significantly accelerating the design optimization to the blade is maximized. Conversely, lower angles result
process. Well-trained surrogate models achieve high in surface plowing or smearing, which deforms but does
accuracy when validated against full CFD-FEA simulations, not remove material. This explains why the leading edge of
making them reliable for real-world applications. The use a blade is particularly vulnerable – it experiences frequent,
of ML-based surrogate models exemplifies the synergy high-angle impacts.
between advanced computational methods and data-driven In addition, boundary layer theory helps explain
approaches. By significantly reducing computational costs how turbulence near the blade surface contributes to
and providing rapid predictions, these models empower uneven particle impacts. Stokes and Presby found that
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researchers and engineers to efficiently analyze erosion flow separation near the trailing edge causes particles to
patterns and optimize turbine blade designs under diverse rebound erratically, creating localized hotspots where
operating conditions. This integration demonstrates the erosion is more severe. In these regions, the turbulent flow
practical impact of ML in addressing complex engineering combined with high particle velocities leads to repeated
challenges. impacts, further intensifying the erosion.
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3.4. Theoretical implications for the study Zainuddin et al. also noted that the material
composition of the blade plays a significant role in the
This theoretical framework outlines a comprehensive degree of surface damage. Blades made of harder materials
understanding of erosion-induced failures in gas turbine or those coated with erosion-resistant coatings, such as
blades by integrating theories on erosion mechanics, TBCs, experience less erosion because these materials
material degradation, and computational modeling. The can better absorb and dissipate the energy from particle
framework provides a solid foundation for addressing the impacts.
following research questions:
(1) R1: How do erosion mechanisms in gas turbines Thus, erosion mechanisms lead to non-uniform material
contribute to localized surface damage? removal, predominantly on blade surfaces exposed to
(2) R2: How does erosion-induced fatigue lead to blade high-velocity gas flow and frequent particle impacts. This
failure over time? damage is concentrated on specific parts of the blade,
(3) R3: How can CFD and FEA simulations predict failure contributing to localized surface wear that degrades the
points and improve blade design? overall performance of the turbine. Over time, this uneven
material loss can alter the blade’s aerodynamic profile,
These theoretical pillars not only support the increasing turbulence and drag while reducing efficiency.
exploration of erosion but also guide the development of In addition, the resulting stress concentrations from
practical solutions, including new materials, coatings, and erosion-induced surface irregularities accelerate crack
computational tools for predicting and mitigating erosion formation, further compromising the blade’s structural
in gas turbines. This framework forms the basis for future integrity.
research aimed at enhancing the durability and efficiency
of turbine blades, ultimately contributing to more reliable 3.4.2. Mechanism of fatigue failure
gas turbine systems. Erosion-induced fatigue occurs as a result of repetitive
3.4.1. Contribution to localized damage particle impacts that weaken the blade surface, creating
stress concentrators (e.g., pits, scratches, and microcracks),
The erosion mechanisms in gas turbines primarily involve which gradually propagate into larger cracks. 49,52 Over
SPE, where hard particles, carried by the high-velocity time, these stress concentrators become critical points
airflow, impact the turbine blade surfaces. 52,57,61 These where fatigue cracks initiate, especially under the cyclic
particle impacts progressively remove material, causing mechanical and thermal loads experienced during gas
localized surface damage that varies depending on factors turbine operation.
such as particle velocity, size, impact angle, and the material 70,72,77
properties of the blade. The Paris–Erdogan law provides a basis for
understanding how small cracks initiated by erosion grow
Localized erosion is primarily observed on the leading over time. It establishes a relationship between the stress
edges, trailing edges, and high-velocity regions of turbine intensity factor and the rate of crack growth. When particles
blades. These areas experience more direct impacts from strike the blade surface, they create microstructural
particles, especially where airflow accelerates due to the damage that intensifies stress concentrations, accelerating
blade geometry. According to Wang et al., particles that crack propagation under the influence of thermal cycling
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impinge on the surface at steep angles (near 90°) cause the (due to repeated heating and cooling) and mechanical
most significant erosion, as the kinetic energy transferred stress (due to rotational forces).

Volume 1 Issue 3 (2024) 79 doi: 10.36922/ijamd.5188