کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1722145 1014714 2015 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Flow and heat transfer characteristics around egg-shaped tube
ترجمه فارسی عنوان
ویژگی های جریان و انتقال حرارت در اطراف لوله تخم مرغی شکل
موضوعات مرتبط
مهندسی و علوم پایه سایر رشته های مهندسی مهندسی دریا (اقیانوس)
چکیده انگلیسی

This paper studies the flow and heat transfer characteristics around a new type of egg-shaped tubes made up of a semicircle upstream and a semi-ellipse downstream, numerically and experimentally, for Reynolds numbers varying from 4 000 to 5 0000 based on the hydraulic diameter. These tubes have axis ratios, ɛ = 1, 1.5, 2, 3, 4, and 5 with the major axis parallel to the main-stream. When ɛ = 1, the tube is a circular one and when 1/ɛ = 0, it is a flat plate. Numerical results show that the minimum value of Cp occurs at an angular position, which decreases as decreases, and the maximum value of Cf gradually increases with the increase of Simulated results agree very well with those available in the existing literature. The egg-shaped tube has a higher favorable pressure gradient at its front and a lower adverse pressure gradient at its back, that helps the flow delay a separation from the tubes' surface. Empirical correlations for each tube are obtained by numerical simulations relating the dimensionless heat transfer coefficient with the Reynolds Number and the Prandtl Number. The performance evaluation criterion (PEC) is used to analyze the level of the heat transfer enhancement for egg-shaped tubes. It is found that an egg-shaped tube with ɛ = 2 has the best overall heat transfer performance when Re > 11952.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Hydrodynamics, Ser. B - Volume 27, Issue 1, February 2015, Pages 76-84