Numerical Investigation of Particle Impact Velocity in a Jet Impact Tester for Gas Solid Flow

Jet impingement tester (JIT) is widely used to evaluate the erosive wear behaviour of the materials subjected to repetitive impact of the solid particles in a fluid. Accurate knowledge of the particle impact velocity on the target surface is crucial for conducting experiments with JIT. The dynamic interaction between particles and the fluid is intricately influenced by the drag force, which induces fluctuations in both particle and fluid velocities. In the present work, Computational Fluid Dynamics (CFD) based simulations are conducted to determine the particle impact velocity on the target surface in a JIT. The Eulerian-lagrangian approach is adopted to simulate the continuous gas phase and discrete particle phase in the flow domain. The effects of mass flow rate, tube length downstream of the nozzle exit (accelerating tube), nozzle exit area, and the distance between the specimen and the accelerating tube exit are investigated. It has been observed that the particle velocity at the nozzle exit is significantly less, approximately one-fifth of the fluid velocity. However, attachment of a tube at nozzle exit (accelerating tube) causes the increase in particle velocity downstream to the nozzle exit and during impact at the target surface. Further, the change in particle impact velocity with the nozzle exit area and space between the specimen and accelerating tube exit is analysed and discussed. These findings provide a better understanding of particle impact velocity in a JIT, which can help standardize test data and improve the reliability of erosion testing for different applications.