Erosion failure mechanisms in turbine stage with twisted rotor blade

Ilieva, Galina

doi:10.1016/j.engfailanal.2016.07.008

Cited by 25 publications

(17 citation statements)

References 25 publications

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“…The Realizable k-ε model gives a new formulation for turbulent viscosity and dissipation rate and is comparatively new from the other k-ε turbulence models. Ilieva [39] applied the Realizable k-ε turbulence model in the research of erosion failure mechanisms in turbine stage with twisted rotor blades.…”

Section: Multiphase Flow Modelmentioning

confidence: 99%

Multicomponent Water Effects on Rotating Machines Disk Erosion

Yang

Hou

et al. 2020

Water

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When sand particles are entrained into carrier flow, such as liquid, a strong interaction occurs with the surface of the metallic material, resulting in serious erosion damage. However, the effect of the physical properties of particles and materials on erosion characteristics has not been well studied. In this paper, the erosion-wear behavior of a rotating disc surface under the action of solid–liquid two-phase flow was studied by using the discrete particle model (DPM). The wear effects on the surface of sample due to particle diameter (d = 0.1 mm, d = 0.2 mm, d = 0.3 mm, d = 0.4 mm), particle volume fraction (CV = 2%, CV = 3%, CV = 4%, CV = 5%), and particle inlet velocity (v = 1.05 m/s, v = 2.05 m/s, v = 3.05 m/s, v = 4.05 m/s) were analyzed using representative values of operating conditions of rotating machines. The results show that the wear amount increases exponentially with the radius, whilst the maximum wear amount increases faster than the average wear amount with the particle volume fraction. The surface wear grows inversely with the particle diameter but slightly with the particle inlet velocity. A case study of stainless steel samples at different radius positions on the surface of rotating disc is carried out using a mixed velocity of sand and water of 2.05 m/s, an average particle size of 0.1 mm, and a concentration of CV = 2.5%. The experiments show the wear amount increases with the radius on the surface of the rotating disc, just as predicted by the numerical simulation. Two important findings emerge from the study: (1) the wear morphology of the specimen surface develops from two to three regions; (2) when the basal body is rotating at high speed, the wear degree is influenced more by the circumferential than particle inlet velocity. The wear morphology was observed by using a scanning electron microscope (SEM). It exhibited a mixture of fine and coarse scratches and pits, and the distribution of these varied according to the radial distance of the disc.

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Section: Multiphase Flow Modelmentioning

confidence: 99%

Multicomponent Water Effects on Rotating Machines Disk Erosion

Yang

Hou

et al. 2020

Water

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“…• Boundary layer separation much before the trailing edge is attained, leads to formation of droplets of various diameters, most of them are condensation nuclei in the process of blades streaming by two-phase flow [36].…”

Section: Turbulence and Condensation Effects In Two-phase Flows In Tumentioning

confidence: 99%

“…From structural point of view, coarse droplets together with the turbulence impact blade surfaces, leading to erosion and efficiency decrease [36].…”

Section: Turbulence and Condensation Effects In Two-phase Flows In Tumentioning

confidence: 99%

On Turbulence and its Effects on Aerodynamics of Flow through Turbine Stages

Ilieva¹

2017

Turbulence Modelling Approaches - Current State, Development Prospects, Applications

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In reality, the flows encountered in turbines are highly three-dimensional, viscous, turbulent, and often transonic. These complex flows will not yield to understanding or prediction of their behavior without the application of contemporary and strong modeling techniques, together with an adequate turbulence model, to reveal effects of turbulence phenomenon and its impact on flow past turbine blades. The discussion primarily targets the turbulence features and their impact on fluid dynamics; streaming of blades, and efficiency performance. Turbulence as a phenomenon, turbulence effects and the transition onset in turbine stages are discussed. Flow parameters distribution past turbine stages, approaches to turbulence modeling, and how turbulent effects change efficiency and require an innovative design, among others are presented. Furthermore, a comparison study regarding the application and availability of various turbulence models is fulfilled, showing that every aerodynamic effect, encountered of flow pass turbine blades can be predicted via different model. This work could be very helpful for researchers and engineers working on prediction of transition onset, turbulence effects, and their impact on the overall turbine performance.

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“…σ R = residual (compressive) stress at the surface after peening at a certain impact velocity (Pa) Introduction Current research on droplet impingement erosion of metallic surfaces is typically related to the lower pressure stages in steam turbines where the blades suffer from erosion due to the high water content of the steam [1][2][3] . Another industrial application suffering from droplet impingement erosion is Liquified Natural Gas (LNG) transport.…”

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confidence: 99%

“…Recently, work on the modelling of drop impact-induced stresses and related wear, is presented by Slot et al 14,15 , Amirzadeh et al 16,17 , and Castorrini et al 18 , for relatively low impact velocities (<150 m/s), for Young's moduli that are representative for polymers and elastomers (<5 GPa) and, more importantly for fully elastic deformation during impact. The physical and metallurgical mechanisms which determine the droplet impingement erosion incubation period (I p ), for metallic surfaces however, are presently not fully understood [1][2][3]5 . As a result, empirical approaches are used for the assessment of droplet impingement erosion sensitive situations involving metallic surfaces 1,4,9,10 .…”

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confidence: 99%

Fatigue-based model for the droplet impingement erosion incubation period of metallic surfaces

Slot¹,

Matthews

Schipper

et al. 2020

Preprint

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Droplet impingement of metallic surfaces at high impact velocities results, after some time, in erosion of the surface due to fatigue. By extending our previously published analytical model to enable the use of experimental fatigue data (S-N curves), here, for the first time, a wide range of experimental liquid droplet erosion incubation period test states for both ferrous (stainless steel AISI 316) and non-ferrous (aluminium 6061-T6) engineering metals have been investigated. To achieve this, the developed model includes additional surface hardening and a residual compressive stress state at the surface due to a water drop peening effect. As such, the interrelation of the physical and mechanical properties that follows from the model has been used to identify how changes in selected metal properties might enhance droplet impingement erosion incubation life. Model predictions for both metals, using fatigue data from S-N curves from different literature sources, showed for the droplet impact velocity range of 140 to 400 m/s an excellent agreement with results from a multi-regression equation as determined from an ASTM interlaboratory test program.

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Erosion failure mechanisms in turbine stage with twisted rotor blade

Cited by 25 publications

References 25 publications

Multicomponent Water Effects on Rotating Machines Disk Erosion

Multicomponent Water Effects on Rotating Machines Disk Erosion

On Turbulence and its Effects on Aerodynamics of Flow through Turbine Stages

Fatigue-based model for the droplet impingement erosion incubation period of metallic surfaces

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