بررسی عددی تاثیر ضریب لغزش بر رفتار جریان گاز در کانال با سطح زبر با کمک شبکه بولتزمن

نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانشکده مهندسی مکانیک، دانشگاه صنعتی امیرکبیر، تهران، ایران

2 پژوهشکده انرژی، دانشگاه صنعتی امیرکبیر، تهران، ایران

چکیده

در این مقاله تاثیر ضریب لغزش بر جریان گاز رقیق در میکروکانال با سطوح زبر و حساسیت رفتار جریان نسبت به این ضریب، در رژیم لغزشی و در محدوده تراکم ناپذیر، به کمک روش شبکه بولتزمن مطالعه شده است. نتایج در قالب تغییرات سرعت لغزشی موضعی، نمایش خطوط جریان و عدد پوازی متوسط در ناحیه توسعه یافته هیدرودینامیکی بیان شده است. به منظور حساسیت سنجی نتایج تحت تاثیر پارامتر ضریب لغزش، مطالعه در نسبت ارتفاع و تراکم زبری های مختلف و همچنین در اعداد نادسن متفاوت انجام شده است. همچنین، در این تحقیق نشان داده‌شده‌است که با افزایش ارتفاع زبری، حساسیت نتایج نسبت به پارامتر ضریب لغزش انتخابی افزایش می یابد و در تراکم زبری های مختلف حساسیت نتایج نسبت به این ضریب اختلاف ناچیزی دارد. در رژیم نزدیک به حالت پیوسته، روند تغییرات عدد پوازی نسبت به پارامتر ضریب لغزش در سطوح صاف و زبر اختلاف نسبتا زیادی دارد و با رقیق‌تر شدن گاز این اختلاف کاهش می یابد و روند تغییرات مشابهی مشاهده می شود.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Sensitivity Analysis of Fluid Flow to Slip Coefficient Using Lattice Boltzmann Method

نویسندگان [English]

  • E. Dorari 1
  • M. Saffar-Avval 1
  • Z. Mansoori 2
1 Mechanical Engineering Department, Amirkabir University of Technology, Tehran, Iran
2 Energy Research Center, Amirkabir university of technology, Tehran, Iran
چکیده [English]

In this paper the effect of slip coefficient on incompressible gas slip flow and the sensitivity of fluid flow behavior to this coefficient in a rough microchannel are investigated using the lattice Boltzmann method. Local slip velocity, streamline contour plots and average Poiseuille number in hydrodynamically developed region are studied and presented. Sensitivity analysis is performed in different relative roughness heights as well as different densities of surface roughness and for different Knudsen numbers. It is shown that as the relative roughness height increases, the sensitivity of Poiseuille number to this coefficient, which is illustrated by the slope of the Poiseuille number versus slip coefficient curve, is increased, while negligible sensitivity difference is seen when different roughness densities are studied. In near continuum flow, the slope of the Poiseuille number curve versus slip coefficient in rough and smooth surface is different, and this trend becomes more similar as the Knudsen number increases.

کلیدواژه‌ها [English]

  • Microchannel
  • Slip regime
  • Surface roughness
  • Tangential momentum accommodation coefcient
  • Slip coefcient
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