Page 73 - IJAMD-1-3

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

The operational efficiency of a system is intricately tied cutting-edge insights and advancements in this field, this
to the thermal environment, where an observed trend in review aims to consolidate a comprehensive perspective on
literature indicates a notable correlation between increased the evolving strategies and mitigation techniques necessary
maximum temperatures and heightened efficiency, while to combat the persistent threat posed by SPE within
lower minimum temperatures contribute to this effect. industrial equipment and gas turbine systems. The article
Notably, the lower limit of attainable temperatures is provides an in-depth look at erosion-induced damage
constrained by ambient conditions, creating a direct and in gas turbine blades, identifying failure mechanisms
crucial relationship between overall efficiency and the and influencing factors that significantly impact the
maximum achievable temperature. This relationship is performance and longevity of these components. The
4,5
particularly pronounced at the turbine inlet, where the gas primary mechanisms of failure due to erosion are SPE,
temperature reaches its peak, rendering the turbine blades material fatigue, and structural deformation, each
exceptionally vulnerable to significant thermal stresses. influenced by a set of operational and environmental
Consequently, current research endeavors are ardently factors. 14,15 Table 1 depicts the different failure mechanisms
focused on the development of advanced superalloys in gas turbine blades.
capable of withstanding and operating effectively under
these elevated temperature regimes. 3,4,6,7 Such endeavors are 1.1. Primary failure mechanisms
pivotal in ensuring sustained performance and durability The high-velocity impact of solid particles carried by the
under demanding thermal conditions. turbine’s airflow is the leading cause of surface degradation
16
The focus of this article lies not in the investigation of in turbine blades. When these particles strike the blade
thermal stress impacts but rather in the comprehensive surfaces, particularly the leading and trailing edges, they
7
analysis of the effects stemming from solid particulate matter cause localized material removal. The high-temperature
entrained within the airflow. As these particles traverse environment amplifies this effect, as particles with elevated
the diffuser and compressor sections, an augmented air kinetic energy penetrate and erode the surface, leading
velocity ensues, carrying the solid particulates alongside. 2,3,8 to cumulative surface damage. SPE causes severe impact
Consequently, the impingement of these particles, in areas exposed to massive turbulent flows, such as the
combined with the elevated temperature and velocity, blade’s leading edge, where particle impacts are frequently
induces a pronounced erosion effect, posing a significant unpredictable and direct.
threat to the structural integrity of the blade material. This The repeated impacts of solid particles create small pits,
challenge turns the spotlight to the necessity in developing scratches, and micro-cracks on the blade surface, which
erosion-resistant superalloys, with researchers actively serve as stress concentrators. These stress concentrators
refining these advanced materials. 4,5,9,10 Moreover, to are weak points that contribute to material fatigue, which
fortify the durability of the blades, a multifaceted approach leads to gradual expansion into larger cracks over time. 17,18
involving the integration of specialized coatings, applied Under cyclic mechanical and thermal loading conditions
using diverse methodologies, is being pursued, aiming to typical of gas turbine operation, these cracks propagate
bolster the protective capabilities of the blade substrate further, weakening the blade structure and leading to
alloys. Such comprehensive strategies aim to ensure the failure. Studies referenced in the article, including those
8
sustained operational efficacy and longevity of the turbine by Khushbash et al., demonstrate that SPE-initiated
9
blades within demanding environments characterized by microstructural damage reduces the blade’s load-bearing
solid particulate-laden airflow. capacity over time, eventually leading to catastrophic
Solid particle erosion (SPE) denotes the progressive failure if left unaddressed.
degradation of solid matter caused by the relentless High operational temperatures not only increase
bombardment of minuscule solid elements, posing a susceptibility to erosion but also cause time-dependent
significant challenge in industrial settings, notably within deformation or “creep” in the material. When erosion
the domain of gas turbine blade applications. This strips away protective coatings, it exposes the base
6,11
erosive phenomenon has garnered substantial attention material to oxidizing conditions and creep deformation,
due to its detrimental impact on the operational efficiency further reducing the structural integrity of the blade. 9,10,19
and structural integrity of critical components. In this This effect is particularly noticeable in high-temperature
comprehensive review, the current landscape of research environments where oxidation and thermal cycling
pertaining to SPE is meticulously surveyed, encompassing accelerate material degradation, ultimately leading to
recent breakthroughs, methodologies, and underlying blade rupture or failure. Past researches also highlight how
SPE-induced material degradation. 12,13 By examining the erosion exposes deeper layers of material to heat, which

Volume 1 Issue 3 (2024) 67 doi: 10.36922/ijamd.5188