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تاثیر اختلاف دما در انتقال حرارت و توزیع قطرات چگالش روی سطوح آبدوست و آبگریز | ||
| نشریه مهندسی مکانیک امیرکبیر | ||
| دوره 56، شماره 6، شهریور 1403، صفحه 811-832 اصل مقاله (2.38 M) | ||
| نوع مقاله: مقاله پژوهشی | ||
| شناسه دیجیتال (DOI): 10.22060/mej.2024.22979.7703 | ||
| نویسندگان | ||
| پریسا دهقانی؛ سید مصطفی حسینعلی پور* ؛ حبیب الله اکبری | ||
| دانشکده مکانیک، دانشگاه علم و صنعت، تهران، ایران | ||
| چکیده | ||
| در این پژوهش تاثیر اختلاف دمای بین سطح و هوای مرطوب بر انتقال حرارت و توزیع قطرات بررسی شده است. بنابراین دستگاه تستی ساخته شده تا شرایط محیطی را کنترل کرده و با قرار گرفتن دو نوع سطح آبدوست و آبگریز در معرض هوای مرطوب پدیده چگالش رخ دادهاست. درصد رطوبت نسبی و سرعت جریان هوای مرطوب در تمامی آزمایشها به ترتیب در مقادیر 88 درصد و 5 متر بر ثانیه ثابت نگاه داشته شده و اختلاف دمای لحاظ شده 4، 7 و 10 درجه سانتیگراد بودهاست. میزان انتقال حرارت متغیر با زمان در طول 60 دقیقه انجام آزمایش نشانداده که برای شروع فرآیند چگالش زمانی لازم است که هرچه اختلاف دما و میزان انرژی سطح بیشتر باشد، این زمان کوتاهتر و میانگین انتقال حرارت نیز بیشتر میشود. عکسبرداری از آزمایشها نیز نشان داده که با افزایش اختلاف دما و انرژی سطح، زمان لازم برای افتادن اولین قطره کوتاهتر و قطر هیدرولیکی قطره خارج شده نیز بزرگتر است. نحوه توزیع قطرات در دقیقه 20 ام پس از شروع هر آزمایش نشان میدهد، با افزایش اختلاف دما تعداد قطرات بزرگتر به دلیل افزایش نرخ چگالش بیشتر بوده و نیز تعداد کوچکترین قطرات روی سطح آبگریز بیشتر از آبدوست است. | ||
| کلیدواژهها | ||
| چگالش؛ انرژی سطح؛ اختلاف دما؛ انتقال حرارت؛ توزیع قطرات | ||
| عنوان مقاله [English] | ||
| Effect of temperature difference on condensation heat transfer and droplet distribution on hydrophilic and hydrophobic surfaces | ||
| نویسندگان [English] | ||
| Parisa Dehghani؛ Seyed Mostafa Hosseinalipour؛ Habibollah Akbari | ||
| School of Mechanical Engineering, Iran University of Science and Technology, Tehran, Iran | ||
| چکیده [English] | ||
| The research examined the influence of temperature difference between surfaces and humid air on heat transfer and droplet distribution. A testing apparatus controlled environmental conditions and facilitated condensation on hydrophilic and hydrophobic surfaces. The relative humidity and speed of humid airflow were kept constant at 88% and 5 m/s, respectively, and the temperature difference considered was 4, 7, and 10 degrees Celsius. The varying heat transfer overtime during the 60 minutes has shown that it takes time to start the condensation process; the more the temperature difference and the amount of surface energy, the shorter this time is and the higher the average heat transfer is. The photography of the experiments has also shown that with the increase in temperature difference and surface energy, the time required for the first drop to fall is shorter, and the hydraulic diameter of the dropped drop is bigger. The distribution of the droplets in the 20th minute after the start of each experiment, in which no droplets have left the test surfaces yet, shows that with the increase in the temperature difference, the number of larger droplets is more due to the increase in the condensation rate. The number of the smallest droplets is higher on hydrophobic surfaces than on hydrophilic ones. | ||
| کلیدواژهها [English] | ||
| Condensation, Surface Energy, Temperature Difference, Heat Transfer, Droplet Distribution | ||
| مراجع | ||
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آمار تعداد مشاهده مقاله: 506 تعداد دریافت فایل اصل مقاله: 460 |
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