Particle impact in high-pressure homogenizer valves – A step towards understanding wear and cell breakup in food and beverage processing

In many liquid food processing applications using high-pressure homogenizers (HPHs), particles impact with the solid surfaces of the homogenization device. This may lead to costly wear. For some applications, impact is also postulated to control the desired cell disruption. This contribution uses computational fluid dynamics to study impact of particles on solid surfaces in HPHs, as a step towards design optimization. Effects of particle diameter, density, homogenizing pressure, and impact distance are studied. Results show impacts both on the forcer and on the impingement ring. Few particles hit the forcer, at low velocities and with low angles (‘bracing impacts’). More particles hit the impact ring. These impacts are with higher velocities and typically occur head-on. The effect of both homogenizing pressure and impact ring distance scales according to a previously suggested stagnation pressure model. Results are discussed in the light of wear and cell disruption observations. • Particle impact might contribute to wear and cell disruption in processing. • Impact occurs at both the forcer and at the impingement ring. • Forcer: low velocity, bracing impacts with low probability. • Ring: higher velocity head-on impacts with higher probability. • Effect of impact distance and pressure follows a stagnation pressure model.