Fundamentals of fluid motion in erosion by solid particle impact

On the interaction of particles and turbulent fluid flow

The numerical solution procedure has been developed to analyze gas-particle flow in a solid rocket nozzle. The time-dependent) explicit MacCormack scheme is adopted to solve the governing equations derived from the trajectory model. The velocity, trajectory, and temperature of the solid particles are treated with the Lagrangian approach. To study the particle diffusive velocity, which is included to account for the turbulent effect, the equation of particle number density is solved by the hybrid scheme. The results of this study indicate the level of gas-particle coupling and the differences that can be expected for the different sizes and mass fractions of particles.

Numerical study of gas-particle flow in a solid rocket nozzle

Computational investigation of vertical slurry jets in water

The pneumatic conveyance of fibers within confined channels is particularly relevant to textile engineering, with applications such as transporting individual fibers within rotor spinning machines. The channels of converging shape within these machines are designed to help straighten the orientation of the fibers that have escaped from the opening roller. This allows a satisfactory configuration of fibers to be presented to the spinning rotor surface, which in turn improves yarn and subsequent fabric properties. In this study, a new air/fiber two-phase model is developed to simulate fiber movement within confined channels. The computation is based on the results from single-phase air flow simulations in a one-way coupling Lagrangian strategy for predicting fiber trajectories. Initial fiber position and the underlying air flow pattern are demonstrated to be critical to the final fiber configuration at the exit of the channel. A streamwise straight fiber tends to generate a leading hook, while a cross fiber...

Computational Two-Phase Air/Fiber Flow Within Transfer Channels of Rotor Spinning Machines

A general analysis of gas-particle flows is presented using the hypotheses of a number of particles large enough to consider the solid phase as a continuum and of a volume fraction small enough to consider the suspension as dilute. It is found that the Stokes number (Sk) and the particle loading ratio (beta) are the basic parameters governing the flow. For small values of beta and large values of Sk it is possible to disregard the effect of the particles on the fluid field and simple numerical models based on one-way coupling may be used. However, for larger values of beta and lower Sk, both the fluid and the solid phase flow fields (and as a consequence the overall quantities such as pressure drop and energy dissipation) are determined to be substantially affected by the interphase coupling. A computational model accounting for two-way coupling is presented and found to provide for an accurate simulation. In addition, correlations are developed for determining the pressure drop which increases as a function of beta and Sk, and it is suggested that these correlations may be of practical interest for the investigation of flow metering systems.

M. Di Giacinto

Papers

Two-Way Coupling Effects in Dilute Gas-Particle Flows

Closure to “Discussion of ‘Two-Way Coupling Effects in Dilute Gas-Particle Flows’” (1982, ASME J. Fluids Eng., 104, pp. 311–312)