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11.
12.
添加聚合物对混合层流场特性影响的实验研究 总被引:1,自引:0,他引:1
叙述了适用于粘弹性流体混合层流场的实验装置的设计和研制.采用二维激光多普勒系统对混合层流场进行了测量,得到了平均速度剖面、动量厚度、湍流脉动强度、雷诺应力等一些流场的基本特征量.结果表明,混合层中加入聚合物后流场将有较大的变化,同时也说明本文所研制的实验装置满足实验的要求. 相似文献
13.
Results of experimental investigations of the effect of drying and atomization parameters on counter-current spray drying
are discussed. Based on 96 experimental tests, the local and global distributions of velocity, temperature, drying air humidity
and moisture content of material dried in the drying tower were determined. Analysis of the results showed that the process
of agglomeration during counter-current spray drying depended mainly on air temperature in the atomization zone. 相似文献
14.
Jos Derksen 《Flow, Turbulence and Combustion》2002,69(1):3-33
Turbulent, swirling flows are encountered frequently in chemical engineering practice. In this article, experiments and simulations
on two classes of swirling flows, viz. agitated flows (stirred tanks), and confined swirling flows are discussed. Results
of large-eddy simulations of stirred tank flow are compared with experimental data, mainly phase-resolved LDA data of the
flow in the vicinity of the impeller. Next to the average velocity field, also the turbulent kinetic energy, and the anisotropy
of the Reynolds stress tensor have been assessed. An important application of confined swirling flow is the cyclone separator
(hydrocyclones for the separation of liquids, gas cyclones for gas-solid separation). The flow in a swirl tube geometry exhibiting
many of the typical features of swirl flows (e.g. vortex breakdown) is discussed. Furthermore, a large-eddy simulation of
the gas flow in a high-efficiency Stairmand cyclone separator is presented. Two examples of process modeling based on flow
simulations are briefly treated: orthokinetic agglomeration of crystals in a stirred tank, and particle separation in a cyclone.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
15.
B. Yu B. Zheng C. X. Lin O. J. Pea M. A. Ebadian 《Experimental Thermal and Fluid Science》2003,27(8):855-865
Three-dimensional laser Doppler anemometry measurements are performed on developed laminar flow in three helical pipes. The experimental observations are compared to results of numerical calculations employing the fully elliptic numerical method. Good agreement is found between measured data and numerical results. The three helical pipes, with curvature ratios of 0.0734 and 0.1374 and non-dimensional pitches of 0.0793 and 0.193, are adopted to study the effects of curvature and pitch on laminar flow in the experimental approach. The range of Reynolds numbers is 500–2000 to ensure laminar flow in the entire helical pipe. Both the profile shapes of the normal components of the secondary flow and those of the axial flow along the same centerline present not only similar patterns but also similar change when pitch, curvature ratio, and Reynolds number vary. The results demonstrate comprehensive relationships between the axial flow and the secondary flow. 相似文献
16.
Il Ayranc Guillaume Pinguet Dany Escudi Nevin Seluk Rodolphe Vaillon Frdric Andr 《Experimental Thermal and Fluid Science》2007,31(8):839-847
Measurement of particle concentration by laser Doppler anemometry (LDA) is studied on a vertical air jet seeded by a powder disperser with controlled particle and air flow rates. Particle arrival rate is utilized to retrieve particle number densities from conventional LDA operation. The effect of polydisperse nature of the particles is assessed. Comparisons between measured and estimated particle number densities suggest that only a certain portion of the particle population with a particle size to fringe spacing ratio around unity can be detected. Results indicate that reliable measurement of absolute particle concentration is possible for a particle population of narrow size distribution with an average diameter equivalent to fringe spacing. Present number density measurement technique which is useful for practical purposes with conventional LDA systems is found to yield physically reasonable profiles in both laminar and turbulent regimes. 相似文献
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18.
K. Kní?ek J. Hejtmánek E. Šantavá J. Buršík P. Beran 《Journal of solid state chemistry》2011,184(8):2231-2237
The layered cobaltate La0.30CoO2 was prepared from NaxCoO2 precursor by a solid-state ionic exchange and was characterized by means of X-ray and neutron diffraction, magnetic, thermal and electric transport measurements. The compound consists of hexagonal sheets of edge-sharing CoO6 octahedra interleaved by lanthanum monolayers. Compared to Na+ in the parent system, the La3+ ions occupy only one-third of available sites, forming a 2-dimensional superstructure. The deviation from the ideal stoichiometry La1/3CoO2 introduces extra hole carriers into the diamagnetic LS Co3+ matrix making the sample Pauli paramagnetic. The temperature dependence of the electrical conductivity in La0.30CoO2 follows Mott's T−1/3 law up to about 400 K, which is in contrast with the standard metallic behavior in the Na+ homolog possessing the same formal doping. The experiments are complemented by electronic structure calculations for La0.30CoO2 and related NaxCoO2 systems. 相似文献
19.
Hélène Pellissier Author Vitae 《Tetrahedron》2007,63(16):3235-3285
20.