Heat Transfer and Fluid Flow Analysis in a Finned-Tube Heat Exchanger with Electrohydrodynamic Enhancement

• Main Authors: Min-Jer Lee, 李明哲
• Other Authors: Jiin-Yuh Jang
• Format: Others
• Language: zh-TW
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/06461999361654056483

碩士 === 國立成功大學 === 機械工程學系碩博士班 === 92 === 　　The paper discusses the electrohydrodynamic (EHD) enhancement through 3-D laminar fluid flow and heat transfer over plate oval-finned heat exchangers. The effects of different tube pitch arrangements (in-lined and staggered) and electrode arrangements (square and diagonal) with different applied voltage (VE = 0KV to 16KV) are numerically investigated in detail for the Reynolds number (based on the fin spacing and frontal velocity) ranging from 100 to 1000. It is found that the EHD enhancement is more effective for lower Reynolds number and higher applied voltage. The case of square wire electrode arrangement gives the best heat transfer augmentation. This study identifies a maximum improvement of 243% in the average Nusselt number and a reduction in fin area of 69% as compared that without EHD enhancement. The results are also compared with the corresponding circular tube having the same perimeter. It is shown that EHD is more pronounced in elliptic tube.