کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
658826 1458087 2013 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Convection heat transfer of supercritical pressure carbon dioxide in a vertical micro tube from transition to turbulent flow regime
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی جریان سیال و فرایندهای انتقال
پیش نمایش صفحه اول مقاله
Convection heat transfer of supercritical pressure carbon dioxide in a vertical micro tube from transition to turbulent flow regime
چکیده انگلیسی

This paper presents experimental investigations of the convection heat transfer of carbon dioxide at supercritical pressures in a vertical tube with inner diameter of 99.2 μm for various Reynolds numbers, heat fluxes and flow directions. The effects of buoyancy and flow acceleration due to heating and pressure drop are evaluated and analysed. The results show that the effects of flow acceleration are significant and the local wall temperature varies non-linearly for both upward and downward flows at the pressures in the vicinity of critical point and low inlet Reynolds numbers when the heat fluxes are relatively high. The buoyancy effect on the heat transfer is negligible in micron scale tubes at inlet Reynolds (from 2600 to 6700) and various heat fluxes (from 85 kW/m2 to 748 kW/m2). The flow acceleration due to heating and pressure drop can strongly influence the turbulence and reduce the heat transfer for high heat fluxes and low inlet Reynolds. Comparison of numerical predictions with the experimental data showed that the AKN low Reynolds number turbulence model gave better agreement than the k–ε realizable turbulence model with the enhanced wall treatment.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: International Journal of Heat and Mass Transfer - Volume 56, Issues 1–2, 1 January 2013, Pages 741–749
نویسندگان
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