Effects of surface roughness on natural convection flow above an inclined heating plate

• Main Authors: Po-ChitHuang, 黃柏齊
• Other Authors: Keh-Chin Chang
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/16268990691874567268

碩士 === 國立成功大學 === 航空太空工程學系 === 102 === In this article, a numerical investigation is conducted to analyze the three-dimensional incompressible Navier-Stokes flows through the artificially roughened absorber plates in ventilation ducts. Several types of cross section（rectangle、arciform and equilateral triangle ）and different configurations of selected ribs（e/H = 0.06 - 0.2 and p/e = 1 - 7）have been used as roughness elements. The governing equations are solved with a finite-volume-based numerical method. The commercial finite-volume based CFD code ANSYS FLUENT is used to simulate airflow through artificially roughened absorber plates in ventilation ducts. It was found that equilateral triangular ribs give the better heat transfer augmentation than rectangular one. The induced air flow rate was evaluated in all range of parameters investigated and results suggested that induced flow rate in ducts with equilateral triangular ribs correspond to relative roughness height（e/H）of 0.1 and relative roughness pitch (p/e) of 3 is about 15.2 % higher as compared to smooth ducts.