ISSN:0934-0866    

DOI:10.1002/ppsc.19930100402

出版商:WILEY‐VCH Verlag GmbH    

年代:1993

数据来源: WILEY

摘要:

AbstractThe drawback of conventional sedimentation methods, mainly their extremely long sedimentation time for small particles, can be overcome in two phase flow systems. In this paper several principles which permit the rapid determination of settling rate distributions are discussed. Settling rate distributions can be determined from the accelerated particle movement in a flow of constant velocity at low and high solids concentrations. Another system uses accelerated flow at low solids concentrations. The best utilisation of settling rate applications have socalled cross flow systems as set up in a stagnation point flow, in a flow round a bend, or in the decelerated particle movement perpendicular to a flow of constant velocity.

ISSN:0934-0866    

DOI:10.1002/ppsc.19930100403

出版商:WILEY‐VCH Verlag GmbH    

年代:1993

数据来源: WILEY

摘要:

AbstractAs potential approximation functions for measured two‐dimensional distributions, the two‐dimensional normal distribution and the two‐dimensional log‐normal distribution are presented, in addition to mixed forms in which one of the two variables is linearly and the other logarithmically normally distributed. For all four distribution functions, regression curves are calculated, withxbeing understood as independent andyas dependent variable. The general concept is applied to the specific case of a two‐dimensional distribution of particle sizexand particle velocityy. In this context, a number of particularities result from the fact that a distinction has to be made between concentration‐dependent and flux‐dependen

ISSN:0934-0866    

DOI:10.1002/ppsc.19930100404

出版商:WILEY‐VCH Verlag GmbH    

年代:1993

数据来源: WILEY

摘要:

AbstractThe particle mass loading effect on the flow structure of a two‐phase turbulent jet flow was studied. A particle mass loading ratio ranging from 0 to 3.6 was used as the control parameter. The polystyrene solid particles used had nominal diameters of 210 and 780 μm. The flow Reynolds number, which was based on the pipe nozzle diameter and the fluid‐phase centerline mean velocity, was 2 × 104in the current test. A two‐color laser Doppler anemometer (LDA), combined with the amplitude discrimination method and the velocity filter method, was employed to measure the mean velocity distributions for the particle and fluid phases, and the turbulent intensities and Reynolds stresses of the flow. The two‐phase jet flow field was measured from the initial pipe exit to 90 D downstream. Another one‐component HeNe laser LDA system was also applied to obtain the energy spectra and temporal correlations of the two

ISSN:0934-0866    

DOI:10.1002/ppsc.19930100405

出版商:WILEY‐VCH Verlag GmbH    

年代:1993

数据来源: WILEY

摘要:

AbstractThree‐dimensional transport processes of monosized droplets in a turbulent swirling shear layer were investigated experimentally and theoretically. A model experiment was designed that represents the spray dispersion produced by airblast atomizers. Based on the experimental results, a stochastic dispersion model was developed in the frame of a Lagrangian formulation. Comparison with these experimental data for the dispersion of monosized droplets were made and proved to be satisfactory. The analysis of the remaining differences between calculation and measurement emphasized the importance of an accurate description of gas‐phase turbulence characterist

ISSN:0934-0866    

DOI:10.1002/ppsc.19930100406

出版商:WILEY‐VCH Verlag GmbH    

年代:1993

数据来源: WILEY

摘要:

AbstractFractal dimensions in data space are being used to describe fineparticle systems. The relationship between these new parametric descriptions of fineparticle systems and a more classical description of such system using the classical hyperbolic function is discussed. It is shown that fractal dimensions in data space are useful for presenting data for such diverse systems as pigment clusters in composite materials, avalanching powder systems, ballistically fractured material and pore size distribution of porous bodies as determined by mercury intrusion methods. In particular new data is presented on the usefulness of fractal dimensions for describing the flow properties of powders with and without silica flow agents.

ISSN:0934-0866    

DOI:10.1002/ppsc.19930100407

出版商:WILEY‐VCH Verlag GmbH    

年代:1993

数据来源: WILEY

摘要:

AbstractThe transmission and diffraction of radiation through dense monolayers of monodisperse opaque spheres were studied for the Fraunhofer domain. Theoretical considerations, numerical calculations and experiments on ultrasonic transmission and on laser light transmission and diffraction yielded corresponding results. Complementary studies included the cases of sterically non‐interacting particles (by numerical simulation) and of small particle size parameters (by ultrasonic extinction). Transmission was found to be, in general, a non‐linear function of the monolayer density. Secondary effects on the transmission can be attributed to the effect of the monolayer structure (characterized by the pair correlation function) on the angular distribution of diffracted intensity. The results were found to be in accordance with experimental results on extinction in three‐dimensional sy

ISSN:0934-0866    

DOI:10.1002/ppsc.19930100408

出版商:WILEY‐VCH Verlag GmbH    

年代:1993

数据来源: WILEY

摘要:

AbstractThe effect of the geometry of the fiber ends on the scattered intensities is considered. A new modification of the Rayleighdebye‐Gans (RDG) approximate theory, the Mie Substitution Theory (MST) theory, is introduced. The Boundary Value Method (BVM) for the infinite cylinder, the RDG theory, the Shifrin (SFR) modification of the RDG theory and the MST theory are compared with the EBCM theory for various values of fiber diameter, length, refractive index and for various fiber orientations, including random orientation. Scattering from suspensions of fibers, typical of UICC crocidolite and anthophyllite asbestos fibers, is considered using the BVM, the MST and the RDG theories when the fibers are assumed to be aligned and the MST and the RDG theories when the fibers are assumed to be randomly oriente

ISSN:0934-0866    

DOI:10.1002/ppsc.19930100409

出版商:WILEY‐VCH Verlag GmbH    

年代:1993

数据来源: WILEY

摘要:

AbstractDry test sieving results given by woven wire cloths with a square mesh and by round electroformed apertures were compared using sands of various origin. The difference has been found to be constant and independent of substance and quantile. The quantile obtained on a square mesh was converted into the corresponding quantile on an electroformed sheet of the same nominal aperture by multiplication by a constant factor of 1.21 ± 0.04

ISSN:0934-0866    

DOI:10.1002/ppsc.19930100410

出版商:WILEY‐VCH Verlag GmbH    

年代:1993

数据来源: WILEY

ISSN:0934-0866    

DOI:10.1002/ppsc.19930100401

出版商:WILEY‐VCH Verlag GmbH    

年代:1993

数据来源: WILEY