PSI - Issue 71

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

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Fig. 2. Velocity contour of air flow for inlet velocity of 25 m/s

Fig. 3. Normalized particle velocity variation relative to Axial length for Experimental Fan et al. and Numerical Investigation.

3.2. Effect of acceleration tube To assess the effect of using an acceleration tube downstream to the nozzle, simulations are performed considering a nozzle (length-to-diameter ratio of 4:1) with acceleration tube of 600 mm downstream to the nozzle and without the acceleration tube. The nozzle without acceleration tube is designed according to the ASTM G-76 standard i.e. with a length-to-diameter ratio of 25:1. For consistency, the nozzle exit-to-inlet area ratio and stand-off distance are maintained at 0.5 and 17 mm. The particle velocity characteristics are simulated with both designs for inlet velocities of 15 m/s, 25 m/s and 50 m/s. Fig. 4 presents the variation in particle velocity (V p )-to-fluid velocity (U) ratio with the inlet velocity. It shows that the particle to fluid velocity ratio varies with the inlet velocity for the design without acceleration tube. However, with the acceleration tube downstream to nozzle exit the variation in particle to fluid velocity ratio reduces. This may attribute to the increase in flow path of the particles which helps to extract more energy from the continuous fluid.