کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
662448 1458186 2005 12 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Flow boiling CHF in microgravity
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی جریان سیال و فرایندهای انتقال
پیش نمایش صفحه اول مقاله
Flow boiling CHF in microgravity
چکیده انگلیسی

Poor understanding of flow boiling in microgravity has recently emerged as a key obstacle to the development of many types of power generation and life support systems intended for space exploration. This study examines flow boiling CHF in microgravity that was achieved in parabolic flight experiments with FC-72 onboard NASA’s KC-135 turbojet. At high heat fluxes, bubbles quickly coalesced into fairly large vapor patches along the heated wall. As CHF was approached, these patches grew in length and formed a wavy vapor layer that propagated along the wall, permitting liquid access only in the wave troughs. CHF was triggered by separation of the liquid–vapor interface from the wall due to intense vapor effusion in the troughs. This behavior is consistent with, and accurately predicted by the Interfacial Lift-off CHF Model. It is shown that at low velocities CHF in microgravity is significantly smaller than in horizontal flow on earth. CHF differences between the two environments decreased with increasing velocity, culminating in virtual convergence at about 1.5 m/s. This proves it is possible to design inertia-dominated systems by maintaining flow velocities above the convergence limit. Such systems allow data, correlations, and/or models developed on earth to be safely implemented in space systems.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: International Journal of Heat and Mass Transfer - Volume 48, Issue 15, July 2005, Pages 3107–3118
نویسندگان
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