کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
147717 456398 2014 17 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
X-ray micro-tomography and pore network modeling of single-phase fixed-bed reactors
ترجمه فارسی عنوان
میکرو توموگرافی اشعه ایکس و مدل سازی شبکه های حفره ای راکتورهای تک فاز ثابت
کلمات کلیدی
شبکه های پور رسانه های متخلخل، جریان تک فاز، جریان غیر دارسی، اثرات انتگرال، پراکندگی مکانیکی
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی مهندسی شیمی (عمومی)
چکیده انگلیسی


• 3D pore network extracted from X-ray μ-tomography imaging of a bead pack.
• Non-Darcy flow simulated using pore-throat-pore mesoscopic elements.
• Dissipation dissected into elementary pore/channel linear and quadratic effects.
• Back-mixing via channel retroflow identified and quantified by network model.

A three-dimensional (3D) irregular and unstructured pore network was built using local topological and geometrical properties of an isometric bead pack imaged by means of a high-resolution X-ray computed micro-tomography technique. A pore network model was developed to analyze the 3D laminar/inertial (non-Darcy) flows at the mesoscopic (pore level) and macroscopic (after ensemble-averaging) levels. The non-linear laminar flow signatures were captured at the mesoscale on the basis of analogies with contraction and expansion friction losses. The model provided remarkably good predictions of macroscopic frictional loss gradient in Darcy and non-Darcy regimes with clear-cut demarcation using channel-based Reynolds number statistics. It was also able to differentiate contributions due to pore and channel linear losses, and contraction/expansion quadratic losses. Macroscopic mechanical dispersion was analyzed in terms of retroflow channels, and transverse and longitudinal Péclet numbers. The model qualitatively retrieved the Péclet-Reynolds scaling law expected for heterogeneous networks with predominance of mechanical dispersion. Advocated in watermark is the potential of pore network modeling to build a posteriori constitutive relations for the closures of the more conventional macroscopic Euler approaches to capture more realistically single-phase flow phenomena in fixed-bed reactor applications in chemical engineering.

Figure optionsDownload as PowerPoint slide

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Chemical Engineering Journal - Volume 240, 15 March 2014, Pages 290–306
نویسندگان
, , , , , , , , ,