Flow and heat transfer of confined impingement jets cooling using a 3-D transient liquid crystal scheme |
| |
| Affiliation: | 1. Energy Conversion and Conservation Center, University of New Orleans, New Orleans, LA 70148-2220, USA;2. Department of Mechanical Engineering, Clemson University, Clemson, SC 29634-0921, USA;3. General Electric Corporate R&D, Schenectady, NY 12301, USA;1. School of Mechanical Engineering, Faculty of Engineering, Tel Aviv University, Ramat Aviv 69978, Israel;2. Department of Mechanical Engineering, Karunya University, Tamilnadu, India;3. Fluid Mechanics, Thermal Engineering and Multiphase Flow Research Lab. (FUTURE), Department of Mechanical Engineering, Faculty of Engineering, King Mongkut''s University of Technology Thonburi, Bangkmod, Bangkok, Thailand;4. The Academy of Science, The Royal Institute of Thailand, Sanam Suea Pa, Dusit, Bangkok 10300, Thailand;1. Department of Energy Science and Engineering, I.I.T., Bombay, Mumbai, India;2. Department of Mechanical Engineering, I.I.T., Bombay, Mumbai, India;1. Group of Thermal Turbomachinery (GTT), École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland;2. Institute of Aerospace Thermodynamics (ITLR), Universität Stuttgart, Pfaffenwaldring 31, D-70569 Stuttgart, Germany;3. Alstom, CH-5401 Baden, Switzerland;1. Laboratory of Fundamental Science on Ergonomics and Environmental Control, School of Aeronautic Science and Engineering, Beihang University, Beijing 100191, PR China;2. Institute of Engineering Thermophysics, Chinese Academy of Sciences, Beijing 100190, PR China;3. School of Chemical and Process Engineering, University of Leeds, Leeds LS2 9JT, UK |
| |
| Abstract: | It has been shown that the heat transfer coefficients obtained from using the 1-D transient liquid crystal scheme are higher than those obtained from employing the 3-D scheme when surface heat transfer is highly nonuniform such as on a hot surface subject to jet impingement cooling. This is due to the fact that 1-D method does not include the lateral heat flows induced by local temperature gradients. The objective of this study is to provide a new database of heat transfer coefficient distribution on the jet impingement target surface in the confined cavity by employing a 3-D transient liquid crystal scheme. The study is performed with an 8 × 11 array of confined impinging jets with Reynolds numbers ranging from 1039 to 5175. The 1-D results are higher than the 3-D results with the local maximum and minimum heat transfer values being overvalued by about 15–20% and the overall heat transfer by approximately 12%. In addition, hot-film measurements of the flow structure are conducted to gain insight into the effects of cross-flow on heat transfer behavior. The surface mapping of heat transfer coefficient demonstrates a change from columnar pattern to a horizontal pattern and switching back to the columnar pattern as Reynolds number increased consecutively. This pattern switching is thought to be caused by the competition between jet penetration and the cross-flow buffering effect. A nonuniformity index is defined to provide a quantitative measure for cooling effectiveness for various cases. The results indicate that increased cross-flow degrades the heat transfer performance but increase uniformity. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
