Terminal Velocity Of Single Particle Research Articles

空間率関数とレイノルズ数

The sedimentation rate of multiparticle suspension in a stationary fluid, um, decreases with increasing particle concentrations. The voidage function F(e) is defined as F(e)=v∞/um, where v∞ is the terminal velocity of single particle in the infinite stationary fluid.In order to generalize the voidage function to cover the entire ranges of flow, namely, laminar (St), intermediate (Al), and turbulent (N) flow regions, the following equation is given.FSt(e)=[FAl(e)]m=[FN(e)]2where m varies from 1 to 1.63 continuously with Reynolds number in the intermediate flow region, when calculated from the drag coefficient correlation of a single sphere motion according to Schiller. Previously, Richardson-Zaki has pointed out that m varies from 1 to 2 in the same intermediate flow region and some other investigators reported m to be 1.4 or constant.The voidage function in each flow region, obtained from the correlations of Kozeny-Carman or Ergun, has been found in good agreement with the voidage function of Richardson-Zaki in a certain range of voidage.

Terminal Velocity of Particle Group : Fundamental Research on Pneumatic Conveying

The terminal velocity of single particle was studied long ago by both experimental and theoretical methods. But the research on terminal velocity of particle group has not been done yet. By experimental research, the authors have found that the terminal velocity ut of particle group decreases linearly in proportion to the concentration μ* of particle group and the pressuredrop increases in proportion to the weight of particle group for μ*=0∼130. Next, the pressure drop in pneumatic conveying of wheat was calculated, applying the above relation between ut and μ*. Comparing this with the usual calculation (ut=const.), it has been found that both calculated pressure drops are approximate to the experimental value at the same degree. This shows that the usual calculation (ut=const.) is sufficient to be used for calculating the pressure drop.