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91.
This work is essentially a review of a density functional approach in multiphase hydrodynamics developed by the authors during the last 15 years [Dinariev, J Appl Math Mech 1995;59(5):745–752; Dinariev, J Appl Math Mech 1998;62(3):397–405; Demyanov and Dinariev, Fluid Dynam 2004;39(6):933–944; Demianov et al., “Basics of the Density Functional Theory in Hydrodynamics,” Fizmatlit, Moscow; 2009 (in Russian); Dinariev and Evseev, Fluid Dynam 2010;45(1):85–95]. The basic assumption is a representation of the entropy or the Helmholtz energy of the mixture as a functional that is dependent upon chemical component densities. The hydrodynamic system of equations (local conservation laws for chemical components, momentum, and energy) is used to describe multiphase processes, and the constitutive relations (expressions for stresses, diffusion, and heat fluxes) are derived from entropy growth requirement. The authors present the results of numerical simulations describing static and dynamic multiphase systems. 相似文献
92.
ABSTRACT Results of studies on cooling and drying of powdery and granulated material in a pulsed-fluid bed ( PFB) system with relocated gas stream presented here are related to hydrodynamics and kinetics of these processes. Generalized results in the form of dimensionless equations can be used to determine basic process parameters such as drying time, heat transfer coefficient, pulsed-fluidzation velocity. pressure drop, etc. Results of experimental investigations, supplemented with experiments carried out in a prototype industrial equipment, can be useful for dryer scale-up and are recommended for designing. A comparison of technical and economic parameters of these dryers with the parameters of classical fluid-bed dryers shows many advantages of PFB systems, including, among othen. reduced gas consumption, uniform bed structure and stability of final parameters of the product. Positive estimation of the operation and technological parameters suggests that PFB dryers with relocated gas stream can be applied successfully in industrial practice. 相似文献
93.
Marie-Laurence Tremblay Lingling Xu Muzaddid Sarker Xiang-Qin Liu Jan K. Rainey 《International journal of molecular sciences》2016,17(8)
Spider aciniform (wrapping) silk is a remarkable fibrillar biomaterial with outstanding mechanical properties. It is a modular protein consisting, in Argiope trifasciata, of a core repetitive domain of 200 amino acid units (W units). In solution, the W units comprise a globular folded core, with five α-helices, and disordered tails that are linked to form a ~63-residue intrinsically disordered linker in concatemers. Herein, we present nuclear magnetic resonance (NMR) spectroscopy-based 15N spin relaxation analysis, allowing characterization of backbone dynamics as a function of residue on the ps–ns timescale in the context of the single W unit (W1) and the two unit concatemer (W2). Unambiguous mapping of backbone dynamics throughout W2 was made possible by segmental NMR active isotope-enrichment through split intein-mediated trans-splicing. Spectral density mapping for W1 and W2 reveals a striking disparity in dynamics between the folded core and the disordered linker and tail regions. These data are also consistent with rotational diffusion behaviour where each globular domain tumbles almost independently of its neighbour. At a localized level, helix 5 exhibits elevated high frequency dynamics relative to the proximal helix 4, supporting a model of fibrillogenesis where this helix unfolds as part of the transition to a mixed α-helix/β-sheet fibre. 相似文献
94.
喷射式并流填料塔板流体力学和传质性能 总被引:9,自引:1,他引:8
提出一种新型高效塔板——喷射式并流填料塔板(JCPT),介绍1200mm冷模塔流体力学实验结果和200mm热模塔传质效率,给出了适用于工业设计性能参数的计算关联式。通过与新垂直筛板(NVST)的比较表明,JCPT具有雾沫夹带小、处理能力大、塔板效率高等特点,是一种具有广泛应用前景的新型高效塔板。 相似文献
95.
周华君 《土木建筑与环境工程》2001,23(5):1
水动力数值模型是污染物和泥沙运动过程模拟的前提,已广泛应用于河流海岸工程的规划设计和管理中。用于工程的水动力模型应根据研究目的、地形和水动力特征做适当的简化。本文分析了水动力模拟的基本过程和主要问题,探讨了模型域的选择、模型维度、边界条件、初始条件、计算网格设计、小尺度过程及亚网格尺度过程的参数化、模型验证等问题。 相似文献
96.
PDC钻头井底水力问题的计算机模拟 总被引:8,自引:2,他引:6
井底清岩和切削齿冷却是PDC钻头水力学的突出问题,给出了PDC钻头井底流动、传热的数学模型,并借助泥沙运动力学,根据Maye-Peter公式,由速度场定量计算井底各处可能带走岩屑量的分布,以此来评价清岩能力。较全面地提出了PDC钻头井底流动、传热和清岩的计算机模拟原理和技术方法,可用于了解PDC钻头井底的水力作用效果.改进和完善PDC钻头的水力结构。 相似文献
97.
The developing trend of vehicle is electrical vehicle in future,and fuel cell will become the one of the main batteries of electrical vehicle because of its the prominent properties.The one of current obstacle for fuel cell in popularization and applications is lacking of excellent performance hydrogen storage materials and advanced technologies of preparing nanoparticles for hydrogen storage materials.The principles,typical classifications and characteristics of chemically and physically preparing nanoparticles for hydrogen storage materials are briefly introduced.And it predicts that physical method is going to be the major developing direction for nanoparticles for hydrogen storage material fabrication.The principle,the system composition &characteristics of method by means of combining ball milling with aerosol generation preparing nanoparticles for hydrogen storage materials are expounded.The ball milling process for hydrogen storage material is needed to conduct effective cooling process,and the lower cooling temperature has better milling results.The cooling media for ball milling include room temperature water,ice water,pure ethanol with dry ice and liquid nitrogen.The proper level of vacuum in canister is significant for injecting aerosol particles during the ball milling.In order to maximize the friction force,it is better to design multi-level stirring rod and the profile of stirring rod with large contact area,therefor stirring rod with cylinder has less grinding effect than with ring profile.The more stirring rod with more layers will obtain higher stirring efficiency.The distance between each layer of branches is 2.5times larger than diameter of the ball.The simulation results show that the average speed has 120% increases from 400 rpm to 800 rpm.Based on the kinetic energy equation,it is obtained that there is 350% increase in energy from 400 r / min to 800 r / min.The higher stirring speed will generate the finer material.And the discussion of this article provides a favorable basis of preparing nanoparticles for hydrogen storage materials in fuel cell vehicle. 相似文献
98.
99.
100.
河道洪水演算方法之间参数关系的研究 总被引:7,自引:2,他引:7
本文根据累积量定理推导了马斯京根法与扩散模拟法、加里宁一米留柯夫法与扩散模拟法之间参数关系的表达式,并与参数关系的水动力学推导作了比较,结果表明两者完全一样,本文还给出了滞时演进法与扩散模拟法之间参数的关系、河道洪水演算方法之间参数关系的研究,对概念性流域地貌汇流模型的建立具有一定的理论价值,而且对于认识汇流参数的推移和坦化作用以及汇流模型之间的比较均具有一定的实用价值. 相似文献