粒子群を形成する球形粒子に作用する流体抗力の測定

概要

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In a multiparticle system, the drag force acting on each constituent particle, F_d, is larger than that acting on an isolated single particle ill an infinite expanse of fluid, F_<d∞>. The drag force is affected not only by the fractional void volum, ε, but also by particle Reynolds number, Re_p. The effect of particle concentration on the drag force in a multiparticle system had been mainly measured by Steinour^<(1)>, Ergun^<(2)>, and Wen and Yu^<(3)>. However, those results are not applicable in whole ranges of ε and Re_p, and it seems that some results overestimate F_d acting on uniformly dispersed spherical particles. In this study, we have directly measured the drag force acting on the particle cluster which contains about 1 000 single-sized spherical particles by using a weighing apparatus under the conditions of 0.7≦Re_p≦1 000 and 0.2595≤ε≤0.8869. The experimental data in the viscous flow region (Re_p≤1) are fitted to the data obtained by Steinour. The ratio of drag forces, ζ=F_d/F_<d∞>, slightly decreases with increasing Re_p. When ε is large, the decrease of ζ becomes likely to occur under the conditions of lower Re_p.
一般社団法人日本機械学会の論文
1999-06-25