检索结果-南通市图书馆

Analysis and correlation of fluid acceleration with vorticity and Liutex(Rortex)in swirling jets

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2019年第5期31卷 864-872页

作者： Nan Gui Hou-bo Qi Liang Ge Peng-Xin Cheng Hao Wu Xing-tuan Yang Ji-yuan Tu Sheng-yao Jiang Institute of Nuclear and New Energy Technology Collaborative Innovation Center of Advanced Nuclear Energy TechnologyKey Laboratory of Advanced Reactor Engineering and Safety of Ministry of EducationTsinghua UniversityBeijing100084China School of Engineering RMIT UniversityMelbourneAustralia

The characteristics of the acceleration a and its correlation with the vortex core in the swirling flow are analyzed in this *** swirling flows of four swirl numbers(Sn=n S 0,0.10,0.20 and 0.36)are simulated by the direct numerical simulation,and the fluid mass particles from the inlet of the swirling flow are traced as a database for the current *** correlations of the acceleration a with the vortex identification parameters of R andωare quantified,where R is the parameter of the“Liutex”-method proposed by ***,and its early version is“Rortex”.The probability density functions of the included angles of a-R and a-ωare computed,which are used to clarify the geometrical configuration between a and *** covariance coefficients between a and the parameters of various vortex core criteria(Q,λ2,ΩL,ΩR,ωand R)are computed and their relative levels of correlation are *** to the velocity,the expectation and the rms of the acceleration magnitudes and its projections on R and the plane perpendicular to R are computed for better explaining the correlation features between a and *** is found that a and R are always either perpendicular or parallel to each other with the quantized included angles of∠(a,R)=kπ/2,(k=0,1,2).This confirms the role of R which works as the axis of the vortex exclusively.

关键词： swirling flow acceleration correlation vortex Rortex Liutex direct numerical simulation

Effect of swirling addition on the liquid mixing performance in a T-jets mixer

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2022年第10期50卷 108-116页

作者： Chunhui Li Bin Wu Junjie Zhang Peicheng Luo School of Chemistry and Chemical Engineering Southeast UniversityNanjing 211189China Hubei Sanjiang Aerospace Jianghe Chemical Technology Co. LtdYichang 444200China

swirling addition to the stream is beneficial for the fluid *** work aims to study the mixing process intensification in a conventional T-jets mixer by the swirling *** experimental verification by the planar laser-induced fluorescence technique,large eddy simulation with the dynamic kinetic energy sub-grid stress model is used to predict how the swirling strength(in terms of swirling number,S_(w))and swirling directions affect the mixing performance,*** tracer concentration distribution,mixing time,and turbulent characteristics in the T-jets mixers,Predictions show that the swirling strength is the key factor affecting the mixing efficiency of the *** overall mixing time,τ_(90),can be significantly reduced by increasing S_(w).Vortex analysis shows that more turbulent eddies appear in the collision zone and the turbulent kinetic energy dissipation rate increases obviously with the swirling *** S_(w) is kept constant,the mixing process can be accelerated and intensified by adding swirling to only one stream,to both streams with the opposite swirling directions,or to both streams with the same swirling *** of the mixing process by enlarging the mixer size or increasing the flow rates is also ***,this work provides a new strategy to improve the mixing performance of the traditional T-jets mixers by the swirling addition.

关键词： Mixing T-jets mixer swirling Computational fluiddynamics(CFD) Large eddysimulation

Comparative assessment and analysis of Rortex vortex in swirling jets

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2019年第3期31卷 495-503页

作者： Nan Gui Liang Ge Peng-xin Cheng Xing-tuan Yang Ji-yuan Tu Sheng-yao Jiang Institute of Nuclear and New Energy Technology Collaborative Innovation Center of Advanced Nuclear Energy Technology Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of Education Tsinghua University Beijing 100084 China School of Engineering RMIT University Melbourne VIC 3083 Australia

Recently, a new definition, called Rortex, was proposed to quantify the purely rotational motion of fluids. In this work, based on the DNS data, the Rortex is used to assess and visualize the rotational motion and structure of the vortex in swirling jets in comparison with other kinds of vortex criteria, including Q , λ2,vorticity and Ω criteria. The Rortex vector,Ω, Q and criteria are found to be better than the vorticity criterion for the vortex core identification. The vector triangle formed by the Rortex R , the nonrotational shear S , and the vorticity R is analyzed to give mechanical explanations, especially of the effect of the non-rotational shear on the rotation of fluids. In addition, the probability density distributions (PDF) of the Rortex R , the nonrotational shear S, and the vorticity R are computed. The peak value of the PDF of the vorticity could be used to explain the pure rigid rotation effect and the combination effects of the rigid rotation and the non?rotational shear.

关键词： swirling flow vortex Rortex direct numerical simulation rigid rotation non-rotational shear

Concept of a swirling diffuser in batch blending tanks

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2020年第2期28卷 378-382页

作者： Wojciech Artichowicz Jerzy M.Sawicki Gdańsk University of Technology Faculty of Civil and Environmental EngineeringNarutowicza 11/1280-233 GdańskPoland

The mixing of two or more components belongs to the category of the most common unit operations, both in technology and in nature. One particular version is homogenization(blending), the effectivity of which is strongly related to the blending time. Among many differentiated individual solutions of mixing systems used in blenders, one should distinguish the class of agitators with diffusers. An analysis of the character of the velocity field during a blending chamber operation leads to the conclusion that it would be of avail to outfit a straight diffuser with different setups of elbows. In consequence, the vertical direction of the inflowing fluid stream would be changed into the horizontal direction of the outflowing stream, which should intensify the blending process. The concept has been verified experimentally, making use of the tracer methodology. The obtained results confirmed the theoretical conclusion that the blending time for the swirling-diffuser was shorter than for the classical straight one.

关键词： Batch blending chamber swirling diffuser Blending time

Numerical investigation on particles removal by bubble flotation in swirling flow

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2022年第6期29卷 961-972页

作者： He-nan Cui Tao Li Yu-lin Zhu Min Tan College of Materials Science and Engineering Chongqing UniversityChongqing 400044China Chongqing Key Laboratory of Vanadium-Titanium Metallurgy and Advanced Materials Chongqing UniversityChongqing 400044China College of Metallurgy and Energy North China University of Science and TechnologyTangshan 063210HebeiChina

The removal of particles is of great importance in many fields including effluent treatment,mineral separation,clean metal production,***,most of the researchers paid their attention to the two-phase flow involving gas–liquid or solid–liquid *** motion and interaction between bubbles and particles in the swirling three-phase flow field were simulated by discrete phase *** swirling flow and the collision between bubbles and particles were governed by compiling the user-defined function *** centripetal pressure gradient force pushes the discrete phases toward the central region,where the collision rate between particle and bubbles is improved ***,it proved beneficially for particle removal to increase the swirling velocity,particularly for larger ***,bubble flotation is an effective method to remove particles from the *** swirling velocity was optimized,which is valuable for industrial design.

关键词： Particle removal swirling flow Blowing bubble Discrete phase model

Algebraically explicit analytical solu-tions for the unsteady non-Newtonian swirling flow in an annular pipe

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2006年第4期49卷 396-400页

作者： CAI Ruixian1 & GOU Chenhua1,2 1. Institute of Engineering Thermophysics, Chinese Academy of Sciences, Beijing 100080, China 2. Graduate School, Chinese Academy of Sciences, Beijing 100080, China Institute of Engineering Thermophysics Chinese Academy of Sciences Beijing China Graduate School Chinese Academy of Sciences Beijing China

This paper presents two algebraically explicit analytical solutions for the incompressible unsteady rotational flow of Oldroyd-B type in an annular pipe. The first solution is derived with the common method of separation of variables. The second one is deduced with the method of separation of variables with addition developed in recent years. The first analytical solution is of clear physical meaning and both of them are fairly simple and valuable for the newly developing computational fluid dynamics. They can be used as the benchmark solutions to verify the applicability of the existing numerical computational methods and to inspire new differencing schemes, grid generation ways, etc. Moreover, a steady solution for the generalized second grade rheologic fluid flow is also presented. The correctness of these solutions can be easily proven by substituting them into the original governing equation.

关键词： analytical solution, Oldroyd-B type fluid, swirling flow, non-Newtonian.

NUMERICAL STUDY OF TURBULENT swirling FLOW IN COMBUSTOR

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 1996年第1期9卷 6-12页

作者： Fu Song(Department of Engineering Mechanics, Tsinghua University, Beijing, China, 100083) Department of Engineering Mechanics Tsinghua University Beijing 100083 China

Numerical computation of turbulent strongly-swirling flows in combustors is presented. Turbulence models examined are based on the transport equations of the Reynolds stresses, i.e., the second moment closures. The particular flows in question include confined as well as free swirling situations where the swirl number is large. It is indicated that the second-moment closure models offer an effective means for predicting strongly swirling flows. In particular, the isotropization of production and convection (IPC) model gives the best overall performance. The study directly serves for the improvement of combustor design.

关键词： combustion chambers swirling turbulence Reynolds stress numerical analysis

Numerical Simulation of swirling Gas-solid Two Phase Flow through a Pipe Expansion

在线全文

学校读者我要写书评

暂无评论

Journal of Thermal Science 2001年第1期10卷 38-45页

作者： JinHanhui XiaJun 等 DepartmentofEnergyEnbgineering ZhejiangUniversityHangzhou310027China DepartmentofEnergyEnbgineerin

A κ- ε -kp muiti-fluid model is stated and adopted to simulate swirling gas-solid two phase flow. A particle-laden flow from a center tube and a swirling air stream from the coaxial annular enter the test section. A series of numerical simulations of the two-phase flow are performed based on 30 μm, 45 μ m, 60 μ m diameter particles respectively. The results fit well with published experimental data.

关键词： numerical simulation swirling two phase flow.

Experimental and Numerical Investigation of swirling Flow on Triple Elbow Pipe Layout

在线全文

学校读者我要写书评

暂无评论

Journal of Flow Control, Measurement & Visualization 2020年第2期8卷 45-62页

作者： Hideharu Takahashi San Shwin Ari Hamdani Nobuyuki Fujisawa Hiroshige Kikura Laboratory for Advanced Nuclear Energy Institute of Innovative Research Tokyo Institute of Technology Tokyo Japan Graduate School of Science and Engineering Tokyo Institute of Technology Tokyo Japan Department of Mechanical Engineering Niigata University Niigata Japan

The secondary flow downstream of a triple elbow layout was studied experimentally and numerically to visualize the flow behavior under swirling inlet flow conditions. The inlet swirling condition was generated by a swirl generator, consisting of a rotary pipe and honeycomb assembly. The experiments were carried out in turbulent water flow condition at Reynolds number Re = 1 × 104 and inlet swirl intensity S = 1. Ultrasonic measurements were taken at four locations downstream of the third elbow. The two-dimensional velocity field of the flow field was measured using the phased array ultrasonic velocity profiler technique to evaluate the flow field with separation. Furthermore, a numerical simulation was performed and its results were compared with the experimental data. The numerical result was obtained by solving three-dimensional, Reynolds-averaged Navier-Stokes equations with the renormalization group k-ε turbulence model. The experimental results confirmed that the swirling flow condition modified the size of the separation region downstream of the third elbow. A qualitative comparison between the experimental and CFD simulation results of the averaged velocity field downstream of the third elbow showed similar tendency on reverse flow.

关键词： swirling Flow Triple Elbow Ultrasound Phased Array Sensor Velocity Profile CFD Numerical Simulation