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Spaces with σ-point-discrete N_0-weak bases

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Applied Mathematics(A Journal of Chinese Universities) 2013年第1期28卷 116-126页

作者： shen rong-xin LIN Shou Department of Mathematics Taizhou Teachers' College Department of Mathematics Nanjing University Department of Mathematics Ningde Normal University

It is discussed in this paper the spaces with σ-point-discrete N_0-weak bases. The main results are：（1） A space X has a σ-compact-finite N_0-weak base if and only if X is a k-space with a σ-point-discrete N_0-weak base; （2） Under （CH）, every separable space with a σ-point-discrete N_0-weak base has a countable N_0-weak base.

关键词： N_0-weak base σ-point-discrete network σ-compact-finite network separable space.

A STUDY ON THE FLOW IN HELICAL ELLIPTICAL PIPES WITH GALERKIN METHOD

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Journal of Hydrodynamics 2006年第1期18卷 70-76页

作者： MA Jian-feng shen xin-rong ZHANG Ben-zhao ZHANG Ming-kan Department of Mechanics Zhejiang University Hangzhou 310027 China

The fully developed laminar flow in helical elliptical pipes is influenced by curvature, torsion and aspect ratio of cross-section. With the aid of the symbolic manipulation technique, the governing equations were solved by the Galerkin method, The procedures of implementing the Galerkin method for flows in curvilinear pipes were discussed. The effects of the aspect ratio and torsion on the flow structure, wall shear stress and flow ratio were examined in detail. The results show that the flow characteristic for aspect ratio larger than unit is quite different from those for the aspect ratio smaller than unit.

关键词： Galerkin method helical elliptical pipe secondary flow

LAMINAR DEVELOPING FLOW IN THE ENTRANCE REGION OF ROTATING CURVED PIPES

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Journal of Hydrodynamics 2006年第4期18卷 418-423页

作者： MA Jian-feng shen xin-rong ZHANG Ming-kan ZHANG Ben-Zhao Department of Mechanics Zhejiang University Hangzhou 310027 China

Three-dimensional laminar flow in the entrance region of rotating curved pipes was investigated. The governing equations were written in an orthogonal curvilinear coordinate system and solved with a fully three-dimensional numerical method. The development of secondary flow, axial velocity, local and average friction factors for different cases of rotation were given and discussed in detail. The results show that rotation influences the flow structure and friction factor greatly and that the secondary flow is sink-type in the early stage of development and then turns to vortex structure. The average friction factor and the intensity of secondary flow have drastic decrease near the entrance. At some proper rotation, the average friction factor can be noticeably reduced.

关键词： developing flow secondary flow rotating curved pipe

FLOW AND HEAT TRANSFER OF OLDROYD-B FLUIDS IN A ROTATING CURVED PIPE

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Journal of Hydrodynamics 2008年第1期20卷 39-46页

作者： shen xin-rong ZHANG Ming-kan MA Jian-feng ZHANG Ben-zhao Institute of Fluid Engineering Zhejiang University Hangzhou 310027 China

The flow and convected heat transfer of the Oldroyd-B fluids in a rotating curved pipe with circular cross-section were investigated by employing a perturbation method. A perturbation solution up to the second order was obtained for a small curvature ratio, κ. The variations of axial velocity distribution and secondary flow structure with F, Re and We were discussed in detail in order to investigate the combined effects of the three parameters on flow structure. The combined effects of the Coriolis force, inertia force and elastic force on the temperature distribution were also analyzed, which are greater than the adding independent effects of the three forces. The variations of the flow rate and Nusselt number with the rotation, inertia and elasticity were examined as well. The results show the characteristics of the heat and mass transfer of the Oldroyd-B fluids in a rotating curved pipe.

关键词： Oldroyd-B fluids flow structure convected heat transfer rotating curved pipe

FLOW OF OLDROYD-B FLUID IN ROTATING CURVED SQUARE DUCTS

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Journal of Hydrodynamics 2007年第1期19卷 36-41页

作者： ZHANG Ming-kan shen xin-rong MA Jian-feng ZHANG Ben-zhao Institute of Fluid Engineering Zhejiang University Hangzhou 310027 China

The fully developed Oldroyd-B fluid flow through rotating square ducts was numerically studied. The effects of the rotation on secondary flow, axial velocity, and axial normal stress were examined in detail. The results indicated that all of the secondary flow, the axial flow, and the axial normal stress were evidently affected by the rotation. The Taylor-Proudman phenomenon could be observed in the flow. For the secondary flow, the four vortices structure and the six vortices structure were described. Recent studies also showed the effects of rotation on the axial normal stress.

关键词： curved ducts Oldroyd-B fluid rotating axialnormal stress

THE FLOW IN ROTATING CURVED CIRCULAR PIPE

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Journal of Hydrodynamics 2000年第1期12卷 108-116页

作者： Zhang Jin suo, shen xin rong, Zhang Ben zhao Department of Mechanics, Zhejiang University, Hangzhou 310027, P.R.China Zhejiang Univ Hangzhou China

The combined effects of the system rotation (Coriolis force) and curvature (centrifugal force) on the flow in rotating curved circular pipe with small curvature are examined by perturbation method. A second order perturbation solution is presented. The secondary flow structure and the primary axial velocity distributions are studied in detail. The loops of the secondary flow are more complex than those in a curved pipe without rotation or a rotating straight pipe. Its numbers depend on the body force ratio F which represents the ratio of the Coriolis to the centrifugal force. The maximum of the axial velocity is pushed to either outer bend or inner bend, which is also determined by F. The results are confirmed by the results of other authors who studied the same problem by different methods.

关键词： secondary flow curved pipe perturbation method

THE GAS-PARTICLE FLOW AND EROSION IN BENDS WITH A RECTANGULAR CROSS-SECTION

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Journal of Hydrodynamics 1999年第1期11卷 64-72页

作者： Zhang Jing-ping Zhang Ben-zhao shen xin-rong The State Key Laboratory of Fluid power Transmission and Control Zhejiang. UniversityHangzhou 310027 P. R. China Dept. of Mechanics Zhejiang University Hangzhou 310027 P. R. China

In this paper, the computational results of a gas-particle two phase flow in a bend with a rectangular cross-section is presented. The movement of the particles in a curved pipe is numerically analyzed by using random statistical method. The zones and rate of erosion on the wall in a bend are determined. The results are in accordance with the experiment, which indicate that the erosion is influenced by gas velocity, particle size and bend curvature.

关键词： two phase flow in bends. erosion application of tensor

UNSTEADY INTERMITTENT FLOW IN A ROTATING CURVED PIPE

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Journal of Hydrodynamics 2004年第2期16卷 158-165页

作者： YINJian-an shenxin-rong CHENHua-jun ZHANGBen-zhao DepartmentofMechanics ZhejiangUniversityHangzhou310027Chinae-mail：mec-zbzq@emb***

The effects of rotation and intermittent frequency on the flow transition ofsecondary flow and, main flow were examined in detail. Certain hitherto unknown flow patterns werefound. A numerical study was performed to study the characteristics of unsteady intermittent flow ina rotating curved pipe. Due to the rotation, both the Coriolis force and the centrifugal forcecould contribute to the unsteady intermittent flow and some complicated phenomena can be found. Theresults indicate that the unsteady intermittent flow are mainly characterized by five parameters:the Dean number Dn, the curvature κ, the maximal force ratio F (of the Coriolis force to thecentrifugal force in a cycle), the intermittent frequency parameter η (the ratio of a pulslatingtime to the cycle period), and the Womersley number α. Present works shows the natures of theunsteady intermittent flow in a rotating curved pipe.

关键词： unsteady flow secondary flow rotating pipes

On AP-property of Function Spaces

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Chinese Quarterly Journal of Mathematics 2012年第3期27卷 447-451页

作者： shen rong-xin Department of Mathematics Taizhou Teacher's College Taizhou 225300 China Department of Math-ematics Nanjing University Nanjing 210093 China

In this paper, it is discussed the AP-property of function spaces. We prove that for any compact network α for a space X which is closed under finite unions, (1) if C α (X) is an AP-space and X is paracompact, then X is a Hurewicz space; (2) if C α (X) is an AP-space which has countable tightness, then C α (X) is discretely generated.

关键词： shen rong-xin(1981-) male native of Taizhou Jiangsu an associate professor of TaizhouTeacher's College Ph.D. engages in general topology.