Investigation of the particle-laden airflow generated by a pseudo-machining operation

A test rig recreating a typical machining induced gas-solid flow is used to investigate the behaviour of the emitted pollutant particles and their effect upon the airflow around the machine tool. The flow is driven by a rotating cylinder and a tangential jet of inertial solid particles. Experimental data concerning both particle flow and air flow are collected by means of phase Doppler particle analyser (PDPA) and particle image velocimetry (PIV). After describing the specific treatments used to discriminate the two phases, complete results are provided and discussed. Additionally, with the main objective being to optimize the design of pollutant capture devices for machining systems, tentative numerical Simulations are carried out and compared to experimental data. For the one-phase case (air flow without particles), good agreement between simulations and experiments is found and the superiority of a wall-function based large eddy simulation (LES) over realizable k-epsilon modelling is highlighted. For two-phase cases, combination of LES and Lagrangian tracking with two-way coupling leads to simulation results that are reasonably accurate considering the low degree of modelling and the empiricism involved. Particle-to-particle collisions, disregarded in simulations, appear to be a predominant phenomenon in the jet source region, thus partly explaining some discrepancies observed between simulations and experiments. (C) 2009 Elsevier Ltd. All rights reserved.