Effect of oblique stator on the aerodynamic performance and erosion characteristics of governing stage blades in a supercritical steam turbine

Proceedings of the Institution of Mechanical Engineers, Part A:

et al. 2022

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Aiming at the problem of particle erosion in top gas pressure recovery turbines, the physical and chemical properties of the sampled gas dust particles are tested in this paper, and particle motion behavior and erosion characteristics in the turbine cascade are investigated by employing a validated numerical method. On this basis, the influence mechanism of adjustable stator angle and rotate speed on the erosion characteristics of blades under variable working conditions is quantitatively explored. Results show that the erosion damage of the first-stage stator S1 and rotor R1 are mainly initiated by particles with different size. The change of adjustable stator angle will change the load and gas enthalpy drop distribution of the cascade, which then affects the impingement velocity and position of the particles. When adjustable stator angle reduces from 44.2 to 25% opening, erosion of S1 trailing edge grows about 20%, while the erosion of R1 trailing edge reduces by 50%. The change of rotating speed will change the relative magnitude of the particle centrifugal force and airflow drag force, which in turn affects the particle’s trajectory and impingement velocity. When rotate speed increases from 3,000 to 4,500 r/min, both the particle impingement velocity and escape rate increase, resulting in doubling of the erosion on blade leading edge and halving of the erosion on blade trailing edge. Finally, for the high rotation speed TRT operating under variable working conditions, some insightful suggestions are given to minimize the erosion damage of the turbine blades.

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Section: Introductionmentioning

confidence: 99%

Study on the solid particle erosion characteristic of top gas pressure recovery turbine under variable working condition

Proceedings of the Institution of Mechanical Engineers, Part A:

et al. 2022

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“…Erosion caused by the solid particles impacting at high speed is commonly observed in industrial production and is one of the main factors impacting the equipment operation safety and economy negatively [ 1 , 2 ]. In thermal power plants, the erosion caused by fly ash and coal dust on the draught fan blades of the boiler may reduce the total pressure by more than 60% [ 3 ], and the oxide particles entering the steam turbine with the steam further erode the key components of the equipment, such as main valve, regulating valve and blade cascades.…”

Section: Introductionmentioning

confidence: 99%

Investigation of the Erosion Damage Mechanism and Erosion Prediction of Boronized Coatings at Elevated Temperatures

et al. 2020

Materials

In this study, the high temperature erosion mechanisms and damage characteristics of a boronized coating have been systematically studied by employing an improved high-temperature accelerated erosion test bench and impact contact theory analyses. Within the scope of the experimental parameters, the erosion rate of the boronized coating under the same erosion conditions was observed to be only one half to one-twelfth of the erosion rate of the substrate. Furthermore, the boronized coating was noted to be less sensitive to the speed of the erosion particles than the plastic substrate, thus, indicating superior and more stable erosion resistance than the base material. The boronized coating exhibited typical brittle fracture characteristics under impact by the high-speed particles. When the particle impact normal stress exceeded the critical stress for crack propagation owing to the coating defects, the surface and subsurface layers of the coating initially formed horizontal and vertical micro-cracks, followed by their gradual expansion and intersection. After destabilization, the brittle coating material was peeled layer-by-layer from the surface of the test piece. At the same incident speed, as the particle size was increased from 65 μm to 226 μm and 336 μm, the size (width) of the erosion cracks on the coating surface increased from 1 μm to 30 μm and 100 μm respectively. Correspondingly, the erosion damage thickness of the coating was enhanced from 15 μm to 50 μm and 100 μm. In the case of the quartz sand particle size exceeding 300 μm, the dual-phase boronized coating did not provide effective protection to the substrate. Furthermore, based on the elastoplastic fracture theory, a prediction model for the erosion weight loss of the boronized coatings within the effective thickness range has been proposed in this study.

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Experimental and numerical studies on rebound characteristics of non-spherical particles impacting on stainless-steel at high temperature

et al. 2021

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