PSI - Issue 71

Abhijit Parate et al. / Procedia Structural Integrity 71 (2025) 256–262

257

Over the years, different small laboratory test rigs were designed to evaluate surface erosion including jet impingement tester (Oka et al., 1997, Wood et al. 1998, Nguyen et al., 2015), whirling arm tester (Lin et al., 1991), Coriolis erosion tester (Clark et al., 2000, Hawthorne et al., 2003), centrifugal erosion tester (Deng et al., 2001), and slurry pot tester (Clark, 1991, Gupta et al. 1995, Gandhi et al. 2003). However, challenges in effectively controlling operating variables have limit the universal acceptance of any type of test rig for surface erosion measurement (Tarodiya and Levy 2021). Correct knowledge on particle impact characteristics in these test rigs could help to standardize the test and improve the reliability of erosion testing. The aim of the present work is to numerically simulate the particulate flow in a jet impingement tester (JIT) for gas-solid flow and develop an understanding about the particle impact velocity on the target surface in a JIT. 1.1. Jet Impingement Tester In a JIT of gas-solid flow, a flat specimen in subjected to a jet of gas-solid mixture. The setup includes the ejector that directs the mixture through a nozzle, a specimen holder, control valves along with a compressor, and a particle feeder. Fig. 1a illustrates the gas-solid JIT. During testing, the specimen if fixed while can be positioned at any angle, to the flow direction, between 0o and 90o. The erosion rate of the specimen is determined by the ratio of the specimen weight loss before and after the test to the cumulative weight of particles impacting it during the test duration. Over the years, many investigators (Oka et al., 1997, Wood et al. 1998, Nguyen et al., 2015) used JIT to investigate the erosion behavior of the materials. To design the JIT ASTM-G76 guidelines are available. However, investigators used different designs for the components of JIT. Nguyen et al. (2015) used 5.43:1 length-to-diameter ratio nozzle, instead 25:1 ratio nozzle as per ASTM-G76, A 1 m long tube was used upstream to the nozzle. For the numerical investigation, the geometry and mesh of the JIT is generated using ANSYS ICEM 2023. The schematic of JIT is shown in Fig. 1a. The components of JIT are considered as inlet pipe upstream to nozzle for the gas flow of diameter 25.4mm, feeder tube for the injection of particles of diameter 12.5mm, converging nozzle of diameter ratio 0.5, acceleration tube downstream to nozzle of diameter 12.5 mm, specimen of diameter 30 mm and thickness 3 mm and axial distance from the acceleration tube outlet is (standoff distance) 17 mm, cylindrical casing of size 300 mm x 300 mm. A separate geometry without an acceleration tube was also created, maintaining the same specifications except for the upstream length, and incorporating a 25:1 length-to-diameter ratio nozzle in accordance with ASTM-G76 guidelines (ASTM-G76). To generate the mesh, the computational domain is discretized into hexahedral elements with orthogonal quality of 0.75 and 1.7 million elements. Fig. 1b shows the details of the mesh used for the simulations. 2. Numerical Modeling 2.1. Geometry and Meshing

(a) Schematic of Numerical Setup