کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
10127404 1645051 2018 11 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Heat transfer measurement and flow regime visualization of two-phase pulsating flow in an evaporator
ترجمه فارسی عنوان
تجسم اندازه گیری انتقال حرارت و رژیم جریان جریان جریان پالسی دو فاز در یک تبخیر کننده
کلمات کلیدی
جریان شتاب دهنده (جریان پالسی)، دوره پالس نسبت تقویت انتقال حرارت، رژیم دو فاز مایع بخار،
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی جریان سیال و فرایندهای انتقال
چکیده انگلیسی
Heat transfer and flow regime of two-phase R134a pulsating flow in an evaporator have been studied experimentally in this work. Heat transfer coefficient was measured and liquid-vapor two-phase flow regimes was observed under different mass flux, inlet vapor quality and pulsating period. Results show that heat transfer can be enhanced by pulsating flow in short periods (<16 s) with a maximum enhancement of 28% compared with the continuous flow; a deterioration of heat transfer is also observed for flow under long pulsating periods for some conditions, which could be as much as 30%. The effect of mass flux and inlet vapor quality is complex and coupled with pulsation period, which might result from the difference of flow developing between different pulsating periods. The instantaneous flow regime is recorded by a high speed camera and statistically analyzed to explore the mechanism of pulsating flow on heat transfer performance. The statistical analysis of flow regime from the recorded video shows that the flow regime of pulsating flow at on-time remains the same as that of continuous flow with the same instant mass flux, and the flow regime at off-time is mostly stratified, stratified wavy flow depending on the pulsating period. The transition of stratified-wavy flow regime to intermittent, annular flow regime of pulsating flow is the main contribution to the enhancement of heat transfer while dry-out during off-time plays an important role in heat transfer deterioration.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: International Journal of Heat and Mass Transfer - Volume 127, Part C, December 2018, Pages 1014-1024
نویسندگان
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