کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
7005555 | 1455133 | 2018 | 51 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Inter-compartment interaction in multi-impeller mixing: Part I. Experiments and multiple reference frame CFD
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کلمات کلیدی
99-00Reynolds Averaged Navier StokesPIVMRF00-01COMLaser Doppler anemometry - آنومومتر لپ تاپ داپلرLDA - تخصیص پنهان دیریکلهCFD - دینامیک سیالاتRANS - رانRSM - 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
CFD simulations of mixing in single-phase multi-Rushton stirred tanks based on the RANS methodology frequently show an over-prediction of the mixing time. This hints at an under-prediction of the mass exchange between the compartments formed around the individual impellers. Some studies recommend tuning the turbulent Schmidt number to address this issue, but this appears to be an ad-hoc correction rather than physical adjustment, thereby compromising the predictive value of the method. In this work, we study the flow profile in between two Rushton impellers in stirred tank. The data hints at the presence of macro-instabilities, and a peak in turbulent kinetic energy in the region of convergent flow, which both may promote inter-compartment mass exchange. CFD studies using the steady-state multiple reference frame model (unsteady simulations are treated in part II) inherently fail to include the macro-instability, and underestimate the turbulent kinetic energy, thereby strongly over-estimating mixing time. Furthermore, the results are highly mesh-sensitive, with increasing mesh density leading to a poorer prediction of the mixing time. Despite proper results for 1-impeller studies, we do not deem MRF-RANS models suitable for mixing studies in multi-impeller geometries.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Chemical Engineering Research and Design - Volume 136, August 2018, Pages 870-885
Journal: Chemical Engineering Research and Design - Volume 136, August 2018, Pages 870-885
نویسندگان
Cees Haringa, Ruben Vandewijer, Robert F. Mudde,