نوع مقاله : مقاله پژوهشی
نویسندگان
1 گروه مهندسی مکانیک، موسسه غیرانتفاعی اروندان، خرمشهر، ایران
2 دانشگاه آزاد اسلامی واخد اهواز، دانشکده فنی مهندسی، گروه مهندسی مکانیک
3 مکانیک، دانشگاه صنعتی قوچان، قوچان، ایران
چکیده
کلیدواژه‌ها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
In this paper, heat transfer and flow of shear-thinning non-Newtonian liquids with three behavioral indices (n = 0.86, 0.55 and 0.41) in a circular tube under constant heat flux Equipped with a modified twisted tape, have been numerically studied in a laminar, steady state and three-dimensional regime. The finite volume method was used to numerically solve the governing equations and the modified Power-law model is used to analyze the dependence between the stresses and shear rates. The physical model is a circular tube with a standard twisted tape with decreasing its width and also a hollow tape in circular tube with increase in the central cavity of the tape. The results show that the reduction of the tape width in the tube with the twisted tape is inappropriate in terms of thermal efficiency. Instead of removing the outer edges of the tape, hollow tape with different removal ratios was used to improve thermal efficiency. The numerical results show that the removal ratio (hollow width of the tape divided by the initial width) equal to 0.3 in the fluids with behavioral indexes 0.86, 0.55 and 0.41 can cause 17.95%, 18.49% and 19.69% increases thermal performance compared to the best thermal performance mode, respectively. Therefore, hollow twisted tape insert on tube were evaluated as a suitable method to increase thermal performance.
کلیدواژه‌ها [English]
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