Study on The Flow across Circular Cylinder near a Plane Boundary with Mixed Convection

• Main Authors: Jen-Fu Chen, 陳勁甫
• Other Authors: Min-Ter Cheng
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/81472887859928208717

碩士 === 逢甲大學 === 機械工程學所 === 100 === The objective of this research is to investigate the flow interference and mixed convection heat transfer phenomena of a heated circular cylinder adjacent to a flat plate in cross flow with gap ratios from 0.05 to 1.8 and at Reynolds numbers of 3000 and 6600. The analysis was performed by using the FLUENT software; the flow and temperature fields, the flow interference, and the local and the average Nussult numbers were studied in this research. It is observed that the highest heat transfer rate from the cylinder occurs at the gap ratio of 0.1 when the Reynolds number is 3000 and at the gap ratio of 0.2 when the Reynolds number is 6600. No interference is observed when the gap ratio is over 1.8. The effect of natural convection is more obvious for smaller Reynolds numbers and gap ratios. As the gap ratios decrease, the cylinder separation point moves downstream at first and then moves upstream, and the plate separation point moves toward to the cylinder. As G/D<0.2, the gap flow attaches to the cylinder, and this flow behavior alters the cylinder heat transfer phenomenon substantially.