4685

4413

كارشناسي ارشد

مهندسي مكانيك

اصفهان: دانشگاه صنعتي اصفهان، دانشكده مكانيك

1387

نه،73،[II]ص.: مصور،جدول،نمودار

ص.ع.به فارسي و انگليسي

محمود اشرفي زاده

ابراهيم شيراني

88/7/14

احمدرضا پيشه ور، احمدرضا عظيميان

مهندسي مكانيك

ID4413

به فارسي و انگليسي: قابل رويت در نسخه ديجيتالي

Simulation of micro scale flows by modifying boundary condition in lattice Boltzmann method by Ahmad Homayoon a homayoon@iut ac ir Submitted in April 15 2009 Department of Mechanical Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi Supervisor Dr Mahmud Ashrafizaadeh Mahmud@cc iut ac irAbstractThe purpose of this study is to model micro and nano scale flows with Lattice Boltzmann Method LBM The continuity assumption for fluid flows and consequently the validity of Navier stokes equation NSE break down as the channel dimensions are reduced significantly Therefore some particle based methodssuch as Molecular Dynamics MD Direct Simulation Monte Carlo DSMC and LBM are used for the flowsimulation in small scales Among these methods the LBM require less computational resources and withappreciate adjustment can be used for wide range of the Knudsen number Moreover the Lattice BoltzmannEquation LBE is a more fundamental equation compared to the NSE which is in theory valid for allreneges of Knudsen number Therefore the LBM can be used to simulate fluid flows in all regimes uponappreciate adjustments Flows through micro and nano channels have been numerically simulated using a modified lattice Boltzmannmethod LBM These pressure driven flows have been performed inside channels with different dimensionswhich span a wide range of flow regimes covering the slip transition and to some extend the free molecularregimes To cover a wide range of the flow regimes a new relaxation time formulation by considering therarefaction effect and the effective dynamic viscosity has been obtained Different boundary conditions suchas the specular reflection boundary condition SRBC and diffuse scattering boundary condition DSBC have been used The present results agree very well with exiting empirical and numerical data The velocityprofile and pressure distribution are predicted as well as the volumetric flow rate The well known Knudsenminimum has also been captured Keywordslattice Boltzmann method micro and nano flows slip regime transition regime Knudsen minimum effect

محمود اشرفي زاده

ابراهيم شيراني

احمدرضا پيشه ور، احمدرضا عظيميان