Combined Radiation and Convection in the Horizontal Circular Tube with Step-change Wall Temperature

• Main Authors: H. C. Chen, 陳宏彰
• Other Authors: C. Y. Wang
• Format: Others
• Language: zh-TW
• Published: 2002
• Online Access: http://ndltd.ncl.edu.tw/handle/64401030963529813339

碩士 === 國立成功大學 === 航空太空工程學系 === 90 === The study for laminar mixed convection combined with radiation in the thermal entrance region of pipe flow is important in any industrial applications requiring the prediction of short-tube heat transfer performance. This thesis presents an analytical procedure for simultaneous convective and radiative heat transfer with a fully developed laminar flow in a pipe. The fluid is treated as a gray,absobing and emitting medium. Three radiation models have been used to investigate the radiative transfer.The complete radiation model,not only the emission and absorption between thegas and the tube wall.The optically thin radiation model neglects the radiative heat exchanges among gas.In the other radial radiation model,the radiative intensities are regarded as a constant intensity with a wall. When fluids are heated or cooled in horizontal tubes, the resulting temperature difference gives rise to density variation.So, the naturnal convective heat transfer is also important in pipe flow.