سيداميرسجاد خدامي

Solid Particle Erosion (SPE) is recognized as one of the complex damage mechanisms in various industries including power generation, aerospace, petrochemicals, and oil and gas. The presence of corrosion, which often accompanies erosion, adds to the complexities of this phenomenon. This thesis focuses on the experimental and numerical study of solid particle erosion in Ti-6Al-4V alloy under impingement of cornered alumina particles with a nominal diameter of 145 microns, considering the corrosive effect of 37% HCL acid. Initially, by investigating the effect of erodent particle amount on the erosion rate of the alloy, a threshold limit was introduced where the erosion rate becomes independent of the impacting particle number. Subsequently, through microscopic imaging and image processing of erodent particles, statistical distribution of particle geometric characteristics was obtained for computational geometry reconstruction. Based on this data, 1521 angular particles were simulated considering their actual geometries. Finite Element (FE) and Smoothed Particle Hydrodynamics (SPH) techniques were employed to eva‎luate their accuracy in studying the effect of impact angle and particle velocity on the erosion rate. The erosion simulation was assumed as a micro-scale impact problem utilizing five material constitutive models to extract the most accurate model compared to experimental results. According to findings, Zerilli-Armstrong/Johnson-Cook (ZA-JC) constitutive model was selected as the preferred model for further numerical erosion studies development. Results indicated that at impact angles of 35 and 90 degrees and three velocity ranges from 35 to 165 m/s, FE performed better in predicting erosion rate at lower velocities; while SPH provided a more suitable estimation at higher particle velocities. In lower particle velocities, due to forming a protective oxide layer, corroded alloy exhibited an antagonistic effect in the material removal due to erosion-corrosion compared to the total material removal due to pure corrosion and pure erosion. nevertheless, corrosion often resulted in material structure weakening and further material removal from its surface due to erosion. Based on results, there existed a power-law relationship between erosion rate and erodent particle velocity with an approximate power value around 2.5. Corroded alloy also demonstrated this power-law relationship; moreover, increasing corrosion time led to an increase in power-law erosion value up to approximately 3. Numerical study results for corroded material showed that the proposed method in this thesis is reliable for low-time corrosion and loses accuracy for times exceeding 1 hour.

فرسايش ذرات جامد , ذرات گوشه‌دار با هندسه‌ي واقعي , آلياژ خورده‌شده , مطالعه‌ي تجربي - عددي , تيتانيوم رده‌ي 5

Solid particle erosion , Angular particles considering actual geometries , Corroded alloy , Experimental – numerical study , Titanium Grade 5

Seyed AmirSajjad Khoddami

Bijan Mohammadi