دانشگاه صنعتی امیرکبیر نشریه مهندسی مکانیک امیرکبیر 2008-6032 50 2 2018 06 22 Experimental Investigation of the Forced Convection Heat Transfer of Nanofluids in Curved Tubes بررسی تجربی انتقال حرارت جابجایی اجباری نانوسیال در لوله انحنادار 347 358 1389 10.22060/mej.2017.12450.5340 FA محسن نظری دانشکده مهندسی مکانیک، دانشگاه صنعتی شاهرود، شاهرود، ایران شیوا ملکی دانشکده مهندسی مکانیک، دانشگاه صنعتی شاهرود، شاهرود، ایران امین شاکری دانشکده مهندسی مکانیک، دانشگاه صنعتی خواجه نصیرالدین طوسی، تهران، ایران Journal Article 2017 01 25 <span>In this paper, the forced convective heat transfer of Alumina/water nanofluid is experimentally investigated in uniform-temperature curved tubes in the range of 0<De<800. The curved tubes are horizontally installed inside a cubic reservoir which contains phase-change water. A review of the literature shows that analyzing the forced convective heat transfer in uniform-temperature curved tube needs more investigations. In this experimental study, Alumina/water nanofluid with the volume fraction of 0.1 and different curved tubes with the curvature of 0.116, 0.074 and 0.042 are employed. The Nusselt number is calculated after measuring the temperature of the fluid at entrance and exit. Also, the pressure drop of nanofluid inside the curved tubes has been measured. The accuracy of the experimental results has also been validated by the available theoretical data in the literature. The obtained results are reported by using the confidence interval error bars. The results show a maximum increase of 15% in Nusselt number in the presence of Alumina/water nanofluid in comparison to the base fluid. Effects of curvature on heat transfer rate are also studied which show a considerable growth in the convective heat transfer in the tube with small curvatures. </span> <span lang="AR-SA" dir="RTL">در</span><span lang="AR-SA"> <span dir="RTL">این</span> <span dir="RTL">مقاله</span> <span dir="RTL">انتقال</span> <span dir="RTL">حرارت</span> <span dir="RTL">جابه</span> <span dir="RTL">جایی</span> <span dir="RTL">اجباری</span> <span dir="RTL">آب</span> <span dir="RTL">و</span> <span dir="RTL">نانوسیال</span> <span dir="RTL">آب</span> </span><span>– </span><span lang="AR-SA" dir="RTL">آلومینا</span><span lang="AR-SA"> <span dir="RTL">در</span> <span dir="RTL">لوله</span></span><span>­<span lang="AR-SA" dir="RTL">های</span><span lang="AR-SA"> <span dir="RTL">خمیده</span> <span dir="RTL">دما</span> <span dir="RTL">ثابت</span> <span dir="RTL">در</span> <span dir="RTL">محدوده</span> <span dir="RTL">دین</span></span> 81/98 <span lang="AR-SA" dir="RTL">تا</span> 29 / 749 <span lang="AR-SA" dir="RTL">بصورت</span><span lang="AR-SA"> <span dir="RTL">تجربی</span> <span dir="RTL">مورد</span> <span dir="RTL">بررسی</span> <span dir="RTL">قرار</span> <span dir="RTL">گرفته</span> <span dir="RTL">است</span></span>. <span lang="AR-SA" dir="RTL">با</span><span lang="AR-SA"> <span dir="RTL">توجه</span> <span dir="RTL">به</span> <span dir="RTL">مطالعات</span> <span dir="RTL">انجام</span> <span dir="RTL">شده،</span> <span dir="RTL">انتقال</span> <span dir="RTL">حرارت</span> <span dir="RTL">جابه</span> <span dir="RTL">جایی</span> <span dir="RTL">اجباری</span> <span dir="RTL">نانوسیال</span> <span dir="RTL">در</span> <span dir="RTL">لوله</span></span>­<span lang="AR-SA" dir="RTL">های</span><span lang="AR-SA"> <span dir="RTL">خمیده</span> <span dir="RTL">با</span> <span dir="RTL">نسبت</span> <span dir="RTL">انحناهای</span> <span dir="RTL">مختلف</span> <span dir="RTL">و</span> <span dir="RTL">با</span> <span dir="RTL">دمای</span> <span dir="RTL">سطح</span> <span dir="RTL">ثابت</span> <span dir="RTL">بطور</span> <span dir="RTL">کامل</span> <span dir="RTL">بررسی</span> <span dir="RTL">نشده</span> <span dir="RTL">و</span> <span dir="RTL">مطالعات</span> <span dir="RTL">عمیق</span></span>­<span lang="AR-SA" dir="RTL">تری</span><span lang="AR-SA"> <span dir="RTL">در</span> <span dir="RTL">این</span> <span dir="RTL">خصوص</span> <span dir="RTL">نیاز</span> <span dir="RTL">است</span></span>. <span lang="AR-SA" dir="RTL">در</span><span lang="AR-SA"> <span dir="RTL">این</span> <span dir="RTL">آزمایش</span> <span dir="RTL">آب</span> <span dir="RTL">و</span> <span dir="RTL">نانوسیال</span> <span dir="RTL">آب</span> </span></span><span>– </span><span lang="AR-SA" dir="RTL">آلومینا</span><span lang="AR-SA"> <span dir="RTL">با</span> <span dir="RTL">درصد</span> <span dir="RTL">حجمی</span></span><span> 1/ 0 <span lang="AR-SA" dir="RTL">مورد</span><span lang="AR-SA"> <span dir="RTL">استفاده</span> <span dir="RTL">قرار</span> <span dir="RTL">گرفته</span> <span dir="RTL">و</span> <span dir="RTL">همچنین</span> <span dir="RTL">از</span> <span dir="RTL">سه</span> <span dir="RTL">لوله</span> <span dir="RTL">خمیده</span> <span dir="RTL">با</span> <span dir="RTL">نسبت</span> <span dir="RTL">انحنای</span></span> 116 / 0 <span lang="AR-SA" dir="RTL">،</span> 074 / 0 <span lang="AR-SA" dir="RTL">و</span> 042 / 0 <span lang="AR-SA" dir="RTL">و</span><span lang="AR-SA"> <span dir="RTL">مساحت</span> <span dir="RTL">سطح</span> <span dir="RTL">خارجی</span> <span dir="RTL">برابر</span> <span dir="RTL">و</span> <span dir="RTL">جنس</span> <span dir="RTL">یکسان</span> <span dir="RTL">استفاده</span> <span dir="RTL">شده</span> <span dir="RTL">است</span></span>.<span lang="AR-SA" dir="RTL">پس</span><span lang="AR-SA"> <span dir="RTL">از</span> <span dir="RTL">اندازه</span></span>­<span lang="AR-SA" dir="RTL">گیری</span><span lang="AR-SA"> <span dir="RTL">دمای</span> <span dir="RTL">ورودی</span> <span dir="RTL">و</span> <span dir="RTL">خروجی</span> <span dir="RTL">لوله،</span> <span dir="RTL">عدد</span> <span dir="RTL">ناسلت</span> <span dir="RTL">متوسط</span> <span dir="RTL">و</span> <span dir="RTL">افت</span> <span dir="RTL">فشار</span> <span dir="RTL">در</span> <span dir="RTL">لوله</span> <span dir="RTL">اندازه</span></span>­<span lang="AR-SA" dir="RTL">گیری</span><span lang="AR-SA"> <span dir="RTL">می</span></span>­<span lang="AR-SA" dir="RTL">شود</span>. <span lang="AR-SA" dir="RTL">با</span><span lang="AR-SA"> <span dir="RTL">تکرار</span> <span dir="RTL">آزمایش،</span> <span dir="RTL">نتایج</span> <span dir="RTL">به</span> <span dir="RTL">دست</span> <span dir="RTL">آمده</span> <span dir="RTL">به</span> <span dir="RTL">وسیله</span> <span dir="RTL">روابط</span> <span dir="RTL">آماری</span> <span dir="RTL">در</span> <span dir="RTL">بازه</span> <span dir="RTL">اطمینان</span> <span dir="RTL">نمایش</span> <span dir="RTL">داده</span> <span dir="RTL">می</span> <span dir="RTL">شوند</span></span>. <span lang="AR-SA" dir="RTL">همچنین</span><span lang="AR-SA"> <span dir="RTL">از</span> <span dir="RTL">روابط</span> <span dir="RTL">تئوری</span> <span dir="RTL">موجود</span> <span dir="RTL">برای</span> <span dir="RTL">لوله</span> <span dir="RTL">های</span> <span dir="RTL">خمیده،</span> <span dir="RTL">جهت</span> <span dir="RTL">صحت</span> <span dir="RTL">سنجی</span> <span dir="RTL">نتایج</span> <span dir="RTL">تجربی</span> <span dir="RTL">افت</span> <span dir="RTL">فشار</span> <span dir="RTL">استفاده</span> <span dir="RTL">شده</span> <span dir="RTL">است</span></span>. <span lang="AR-SA" dir="RTL">نتایج</span><span lang="AR-SA"> <span dir="RTL">به</span></span>­<span lang="AR-SA" dir="RTL">دست</span><span lang="AR-SA"> <span dir="RTL">آمده</span> <span dir="RTL">نمایانگر</span> <span dir="RTL">افزایش</span> <span dir="RTL">حداکثر</span></span> 15 <span lang="AR-SA" dir="RTL">درصدی</span><span lang="AR-SA"> <span dir="RTL">عدد</span> <span dir="RTL">ناسلت</span> <span dir="RTL">در</span> <span dir="RTL">اثر</span> <span dir="RTL">استفاده</span> <span dir="RTL">از</span> <span dir="RTL">نانوسیال</span> <span dir="RTL">آب</span> </span></span><span>– </span><span lang="AR-SA" dir="RTL">آلومینا</span><span lang="AR-SA"> <span dir="RTL">با</span></span><span> 1/ 0 <span lang="AR-SA" dir="RTL">درصد</span><span lang="AR-SA"> <span dir="RTL">حجمی</span> <span dir="RTL">نسبت</span> <span dir="RTL">به</span> <span dir="RTL">سیال</span> <span dir="RTL">پایه</span> <span dir="RTL">است</span></span>. <span lang="AR-SA" dir="RTL">همچنین</span><span lang="AR-SA"> <span dir="RTL">اثر</span> <span dir="RTL">نسبت</span> <span dir="RTL">انحنا</span> <span dir="RTL">بر</span> <span dir="RTL">انتقال</span> <span dir="RTL">حرارت</span> <span dir="RTL">سیال</span> <span dir="RTL">عامل</span> <span dir="RTL">مورد</span> <span dir="RTL">بررسی</span> <span dir="RTL">قرار</span> <span dir="RTL">گرفته</span> <span dir="RTL">و</span> <span dir="RTL">نشان</span> <span dir="RTL">دهنده</span> <span dir="RTL">افزایش</span> <span dir="RTL">قابل</span> <span dir="RTL">ملاحظه</span> <span dir="RTL">انتقال</span> <span dir="RTL">حرارت</span> <span dir="RTL">جابه</span></span>­<span lang="AR-SA" dir="RTL">جایی</span><span lang="AR-SA"> <span dir="RTL">لوله</span> <span dir="RTL">خمیده</span> <span dir="RTL">با</span> <span dir="RTL">نسبت</span> <span dir="RTL">انحنا</span> <span dir="RTL">کوچک</span> <span dir="RTL">تر</span> <span dir="RTL">در</span> <span dir="RTL">مقایسه</span> <span dir="RTL">با</span> <span dir="RTL">لوله</span> <span dir="RTL">با</span> <span dir="RTL">نسبت</span> <span dir="RTL">انحنای</span> <span dir="RTL">بزر</span> <span dir="RTL">گتر</span> <span dir="RTL">است</span></span>.</span> https://mej.aut.ac.ir/article_1389_2bd7f907b7f5b6bbd91822c0c7b835f6.pdf