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1.
为探究泵站进水流速大小与泵站进水池水流流态、漩涡的产生与发展变化规律,结合泵站实际运行情况,建立引渠、前池、进水池和进水管的泵站物理模型和湍流数学模型,采用VOF模型和非定常的SST k-ω湍流模型对9种不同流速的泵站进水水流特性进行数值模拟,分析不同进水流速的泵站进水池水流流场分布、漩涡涡量的变化及分布规律。研究结果表明:当进水流速为0.322 2~0.564 2 m/s时,泵站表面漩涡的强度随进水流速的增大而增强:当进水流速为0.322 2~0.401 6 m/s时,进水池出现Ⅲ、Ⅳ型漩涡;当进水流速为0.483 5 m/s时,进水池出现Ⅴ型漩涡;当进水流速为0.520 8~0.564 2 m/s时,进水池出现Ⅵ型漩涡。将数值计算结果与模型试验结果进行对比,两者基本吻合。研究结果可为泵站工程设计提供参考。 相似文献
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Hande Fendoğlu Canan Bozkaya Münevver Tezer-Sezgin 《Computers & Mathematics with Applications》2019,77(2):374-388
The unsteady magnetohydrodynamic (MHD) flow of a viscous, incompressible and electrically conducting fluid in a rectangular duct with a perturbed boundary, is investigated. A small boundary perturbation is applied on the upper wall of the duct which is encountered in the visualization of the blood flow in constricted arteries. The MHD equations which are coupled in the velocity and the induced magnetic field are solved with no-slip velocity conditions and by taking the side walls as insulated and the Hartmann walls as perfectly conducting. Both the domain boundary element method (DBEM) and the dual reciprocity boundary element method (DRBEM) are used in spatial discretization with a backward finite difference scheme for the time integration. These MHD equations are decoupled first into two transient convection–diffusion equations, and then into two modified Helmholtz equations by using suitable transformations. Then, the DBEM or DRBEM is used to transform these equations into equivalent integral equations by employing the fundamental solution of either steady-state convection–diffusion or modified Helmholtz equations. The DBEM and DRBEM results are presented and compared by equi-velocity and current lines at steady-state for several values of Hartmann number and the boundary perturbation parameter. 相似文献
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Alexandre Dolgui Semyon Potryasaev Boris Sokolov Marina Ivanova Frank Werner 《国际生产研究杂志》2020,58(7):2184-2199
Recently, the applications of Blockchain technology have begun to revolutionise different aspects of supply chain (SC) management. Among others, Blockchain is a platform to execute the smart contracts in the SC as transactions. We develop and test a new model for smart contract design in the SC with multiple logistics service providers and show that this problem can be presented as a multi-processor flexible flow shop scheduling. A distinctive feature of our approach is that the execution of physical operations is modelled inside the start and completion of cyber information services. We name this modelling concept ‘virtual operation’. The constructed model and the developed experimental environment constitute an event-driven dynamic approach to task and service composition when designing the smart contract. Our approach is also of value when considering the contract execution stage. The use of state control variables in our model allows for operations status updates in the Blockchain that in turn, feeds automated information feedbacks, disruption detection and control of contract execution. The latter launches the re-scheduling procedure, comprehensively combining planning and adaptation decisions within a unified methodological framework of dynamic control theory. The modelling complex developed can be used to design and control smart contracts in the SC. 相似文献
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"精细管理"是开滦(集团)有限责任公司正在推进的一项企业管理建设项目,对于今后企业的发展具有举足轻重的作用。从软件开发角度出发,探讨了如何在企业网络环境下,实现"精细管理"的考核系统设计。 相似文献
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肯定了单立管排水系统的优越性及其广泛发展前途。通过流态分析和计算,指出了影响管道内压力波动的关键问题。对系统中关键配件的结构形式提出了改进意见和设想。指出在高层建筑中推广采用塑料管材的必要性。 相似文献
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通过对南方某市一大型自来水厂集水槽的实验研究,得出了在集水总长不变的前提下,适当改变后段集水孔的面积,从而相对增大前段集水量和集水速度,可使槽前、槽后浊度差减小0.4NTU左右,集水总渠浊度降低0.2NTU左右的结论,具有较好的经济效益。 相似文献
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This study presents the results obtained when Computational Fluid Dynamics is applied to calculating the flow in a domestic kitchen hood at operating conditions. Special emphasis has been placed on parametric modeling of the geometry to permit the rapid modification of fundamental parameters, such as the number of blades and the twisting angle. The governing equations (mass, momentum, energy and turbulence) have been solved using the commercial code, fluent. The predicted characteristic curves of the hood ventilator based on the dimensionless flow and load coefficients have been built, and they are shown to be in good agreement with the experimental data. Finally, the hood model has been incorporated into a full-scale kitchen to predict airflow conditions in this space. 相似文献