Heat transfer mechanism of mist flow

• Main Authors: Chen, Chiao-Hsin, 陳巧欣
• Other Authors: Liu, Yao-Hsien
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/bquenj

碩士 === 國立交通大學 === 機械工程系所 === 104 === 　　Mist flow is a two-phase flow with water droplets and air flow. The heat transfer rate of mist cooling is higher than air cooling. The elements that affect the heat transfer rate of mist flow are the droplet size, flow velocity and droplet concentration. In this study, the heat transfer of mist cooling in vertical channel was experimentally measured and analyzed. The square channel with 40mm hydraulic diameter was used in this experiment. The heater with 250mm length was located on the wall of flow channel downstream. The infrared thermography was used to measure the temperature distribution of heated wall and the heat transfer rate was calculated. Through adjusting the flow rate and heat flux, the heat transfer rate of air cooling and mist cooling was compared. The surface temperature distribution of heated wall in mist cooling was lower and more uniform. The heat transfer rate of mist cooling was higher than air cooling and increased along streamwise direction. With higher heat flux, the heat transfer rate of mist cooling was higher and was fifteen times higher than air cooling.