检索结果-南通市图书馆

Perturbation solutions for asymmetric laminar flow in porous channel with expanding and contracting walls

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2014年第2期35卷 203-220页

作者：张燕林平司新辉 Department of Mathematics and Mechanics University of Science andTechnology Beijing Department of Mathematics University of Dundee

The cases of large Reynolds number and small expansion ratio for the asym- metric laminar flow through a two-dimensional porous expanding channel are considered. The Navier-Stokes equations are reduced to a nonlinear fourth-order ordinary differential equation by introducing a time and space similar transformation. A singular perturbation method is used for the large suction Reynolds case to obtain an asymptotic solution by matching outer and inner solutions. For the case of small expansion ratios, we are able to obtain asymptotic solutions by double parameter expansion in either a small Reynolds number or a small asymmetric parameter. The asymptotic solutions indicate that the Reynolds number and expansion ratio play an important role in the flow behavior. Nu- merical methods are also designed to confirm the correctness of the present asymptotic solutions.

关键词： singular perturbation method regular perturbation method porousexpanding channel expansion ratio

Effect of promoters on dynamics of gas-solid fluidized bed——Statistical and ANN approaches

在线全文

学校读者我要写书评

暂无评论

China Particuology 2007年第6期5卷 401-407页

作者： Y.K. Mohanty K.C. Biswal G.K. Roy B.P. Mohanty Department of Chemical Engineering GIET Gunupur 765 022 Rayagada Orissa India Department of Chemical Engineering NIT Rourkela 769008 Orissa India

In this study, a bubbling fluidized bed column, 99 mm in inside diameter and 960 mm in height, was used to investigate the effect of rod and disc promoters on fluctuation and expansion ratios. Factorial design （statistical approach） and artificial neural network （ANN） models were developed to predict the fluctuation and expansion ratios in this gas-solid fluidized bed with varying gas flow rates, bed heights, particle sizes and densities. The fluctuation and expansion predicted using these statistical and ANN models, for beds with and without promoters, were found to agree well with corresponding experiments. The statistical model was found to be superior to the ANN model due to its ability to take into account both individual and interactive effects. The rod promoters were found to be more effective in reducing bed fluctuation, and in increasing bed expansion at high gas mass velocities.

关键词： Gas-solid fluidized bed Fluctuation ratio expansion ratio Promoter Factorial design Artificial neural network

Optimization Analysis of the Mixing Chamber and Diffuser of Ejector Based on Fano Flow Model

在线全文

学校读者我要写书评

暂无评论

Computer Modeling in Engineering & Sciences 2022年第10期133卷 153-170页

作者： Lixing Zheng Weibo Wang Yiyan Zhang Lingmei Wang Wei Lu School of Electric Power Civil Engineering and ArchitectureShanxi UniversityTaiyuan030006China School of Mechanical Engineering Guangxi UniversityNanning530004China Wind Turbine Monitoring and Diagnosis NTRC of Shanxi ProvinceTaiyuan030006China

An improved model to calculate the length of the mixing chamber of the ejector was proposed on the basis of the Fano flow model,and a method to optimize the structures of the mixing chamber and diffuser of the ejector was put *** accuracy of the model was verified by comparing the theoretical results calculated using the model to experimental data reported in *** in the length of the mixing chamber L_(m) and length of the diffuser L_(d) with respect to variations in the outlet temperature of the ejector T_(c),outlet pressure of the ejector p_(c),and the expansion ratio of the pressure of the primary flow to that of the secondary flow p_(g)/p_(e) were ***,variations in L_(m) and L_(d) with respect to variations in the ratio of the diameter of the throat of the motive nozzle to the diameter of the mixing chamber d_(g0)/d_(c3) and ratio of the outlet diameter of the diffuser to the diameter of themixing chamber d_(c)/d_(c3) were *** distribution of flow fields in the ejector was *** L_(m) and d_(c3) reduced T_(c) and p_(c).Moreover,reducing p_(g)/p_(e) or d_(g0)/d_(c3) reduced T_(c) and p_(c).The length of the mixed section L_(m2),which was determined on the basis of the Fano flow model,increased as pg increased and decreased as d_(c3) *** mixing length L_(m1),which was considered the primary flow expansion,showed the opposite trend with that of L_(m2).Moreover,Ld increased as p_(g)/p_(e) and d_(c)/d_(c3) *** the value of d_(c) was 1.8 to 2.0 times as high as that of dc3,the semi-cone angle of the diffuser ranged between 6°and 12°.At a constant dc/dc3,decreasing T_(c) and pc increased Ld.

关键词： Mixing chamber length Fano flow diffuser diameter ratio expansion ratio optimization method

Flow of micropolar fluid between two orthogonally moving porous disks

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2012年第8期33卷 963-974页

作者：司新辉郑连存张欣欣司新毅 Department of Applied Mathematics University of Science and Technology Beijing Department of Mechanical Engineering University of Science and Technology Beijing College of Water Conservancy and Hydropower Engineering Hohai University

The unsteady, laminar, incompressible, and two-dimensional flow of a mi- cropolar fluid between two orthogonally moving porous coaxial disks is considered. The extension of von Karman＇s similarity transformations is used to reduce the governing partial differential equations （PDEs） to a set of non-linear coupled ordinary differential equations （ODEs） in the dimensionless form. The analytical solutions are obtained by employing the homotopy analysis method （HAM）. The effects of various physical param- eters such as the expansion ratio and the permeability Reynolds number on the velocity fields are discussed in detail.

关键词： homotopy analysis method (HAM) expansion ratio orthogonally movingporous disk

Radial Orientation Mechanism and Experimental Research of Short Fiber in Tread Compound

在线全文

学校读者我要写书评

暂无评论

Journal of Donghua University(English Edition) 2009年第6期26卷 666-672页

作者：汪传生刘彩军边慧光 College of Electromechanical Engineering Beijing University of Chemical Technology College of Electromechanical Engineering Qingdao University of Science and Technology

Combining with Jeffery ：quation and mechanics model of fixed point of Euler rigid btdy, the mechanism and method of short fiber radial orientrion and characteristics of movement in tread extrusion process were studied. The influences of tension flow field and shear flow field in flow channel on short fiber orientation trove been systemically analyzed. The extrusion die, which had a hinder dam by adopting such principle, was designed. The results show that the expansion ratio and expanding angle of cross section are the key factors to determine the radial orientation of short fiber. Mathematical model of short fiber radial orientation was established. The results also show that the best expansion ratio is 3 - 4, the expanding angle is 75°, obtaining the average orientation angle between 70°- 80°, and the rationality of the radial oriented mechanism and the mathematical model are verified.

关键词： short fiber extrusion radial orientation expansion ratio expansion angle

Numerical Modeling on Seismic Performance of Castellated Composite Beam⁃Reinforced Concrete Column Connection

在线全文

学校读者我要写书评

暂无评论

Journal of Harbin Institute of Technology(New Series) 2021年第2期28卷 62-73页

作者： Hongwei Ma Junjie Wang Yang Wang State Key Laboratory of Subtropical Building Science South China University of TechnologyGuangzhou 510640China

The hybrid structure consisting of castellated composite beam and compound spiral hoop reinforced concrete column take full advantages of steel and concrete *** popularize the structural form in real conditions,a beam⁃through⁃type beam⁃column connection is *** 1/2⁃scaled connection specimens were tested and three⁃dimensional finite element models of the beam⁃column connection were set *** longitudinal reinforcements,concrete beam,and column were simulated by link and solid elements,*** influences of the parameters such as expansion ratio,location of web opening,and original height of steel beam were *** results show that connections possessed high initial *** expansion ratio of steel beam showed more important influence on the connection’s ultimate bearing *** the connection models with steel beam expansion ratio of 1.4,the maximum increment of the ultimate bearing capacity of the connection could reach 28%.In order to prevent the local buckling failure of steel beam from occurring near web opening,the expansion ratio of steel beam should not be greater than 1.3.

关键词： castellated composite beam beam⁃column connection finite element analysis expansion ratio

轻质热塑性聚酰亚胺微发泡材料的制备和性能表征

在线全文

学校读者我要写书评

暂无评论

轻质热塑性聚酰亚胺微发泡材料的制备和性能表征