An Algorithm for Attenuation of Turbulence in Particulate Flow Linked to the Fluid-dynamic Code COMMIX-M

摘要

Fluid turbulence is affected by the presence of transported particles in a variety of engineering problems. In particulate flow large particles increase the turbulence intensity while small particles damp it. Numerical simulation of turbulence due to vortex shedding by large particles is made satisfactorily by adding corrective terms in the k-ε model equations. Damping of turbulence due to the shear action of small particles which are entrained by the oscillating motion of the fluid is however more difficult to simulate. This article applies the method proposed by Al Taweel and Landau for turbulence attenuation due to small particles which consists of evaluating a damping function depending on the spectral distribution of turbulence. The method, originally applied in the dissipation range only, is extrapolated to the full spectrum of turbulence and the resulting numerical algorithm is linked to the general purpose computer program COMMIX-M which describes three dimensional multi-phase fluid-dynamic problems. An analytical treatment is presented, which generalizes the Al Taweel-Landau method to the inertial subrange of the spectral domain. Numerical calculations of particulate flow in upward pipe flow, with particles transported by air, are discussed. Comparison with experimental results enables to infer about future work necessary to cope with present limitations of the method proposed.