کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
7005557 | 1455133 | 2018 | 39 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Inter-compartment interaction in multi-impeller mixing. Part II. Experiments, sliding mesh and large Eddy simulations
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کلمات کلیدی
99-00Reynolds Averaged Navier StokesPIVMRF00-01Laser Doppler anemometry - آنومومتر لپ تاپ داپلرLDA - تخصیص پنهان دیریکلهCFD - دینامیک سیالاتRANS - رانRushton - رشتونRSM - روششناسی سطح پاسخParticle image velocimetry - سرعت سنجی تصاویر ذراتSchmidt number - شماره اشمیتMixing - مخلوط کردنReynolds stress model - مدل استرس رینولدزSliding Mesh - مشش کشوییMacro-instability - ناپایداری مکانیکیMultiple impellers - پروانه های چندگانهmultiple reference frames - چندین مرجع مرجع
موضوعات مرتبط
مهندسی و علوم پایه
مهندسی شیمی
تصفیه و جداسازی
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
Steady state multiple reference frame-RANS (MRF-RANS) simulations frequently show strong over-predictions of the mixing time in single-phase, multi-impeller mixing tanks, which is sometimes patched by ad hoc tuning of the turbulent Schmidt-number. In Part I of this work, we experimentally revealed the presence of macro-instabilities in the region between the impellers, as well as a peak in the turbulent kinetic energy in the region where the flow from the individual impellers converges. The MRF-RANS method was found unable to capture both. In this second paper, we show that the sliding-mesh RANS (SM-RANS) approach does capture the effect of macro-instabilities, while still underestimating the turbulent kinetic energy. Consequently, the SM-RANS method mildly over-estimates the mixing time, while being less sensitive to the exact mesh geometry. Large eddy simulations with the dynamic Smagorinsky model reasonably capture the kinetic energy contained in macro-instabilities, and properly assess the turbulent kinetic energy in the region between the impellers, even for crude meshes. Consequently, the mixing time is reasonably assessed, and even under-predicted at the crudest meshes. However, the turbulent kinetic energy and energy dissipation in the impeller discharge stream are poorly assessed by the dynamic Smagorinsky model.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Chemical Engineering Research and Design - Volume 136, August 2018, Pages 886-899
Journal: Chemical Engineering Research and Design - Volume 136, August 2018, Pages 886-899
نویسندگان
Cees Haringa, Ruben Vandewijer, Robert F. Mudde,