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Frontiers in Energy

Front Energ Power Eng Chin    2010, Vol. 4 Issue (4) : 496-506
A way to explain the thermal boundary effects on laminar convection through a square duct
Liangbi WANG(), Xiaoping GAI, Kun HUANG, Yongheng ZHANG, Xiang YANG, Xiang WU
Department of Mechanical Engineering, Lanzhou Jiaotong University, Lanzhou 730070, China
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A way using the reformulation of the energy conservation equation in terms of heat flux to explain the thermal boundary effects on laminar convective heat transfer through a square duct is presented. For a laminar convection through a square duct, it explains that on the wall surface, the velocity is zero, but convection occurs for uniform wall heat flux (UWHF) boundary in the developing region due to the velocity gradient term; for uniform wall temperature (UWT) boundary, only diffusion process occurs on the wall surface because both velocity and velocity gradient do not contribute to convection; for UWHF, the largest term of the gradient of velocity components (the main flow velocity) on the wall surface takes a role in the convection of the heat flux normal to the wall surface, and this role exists in the fully developed region. Therefore, a stronger convection process occurs for UWHF than for UWT on the wall surface. The thermal boundary effects on the laminar convection inside the flow are also detailed.

Keywords convective transport      heat transfer      mass transfer      laminar flow      thermal boundary effects     
Corresponding Authors: WANG Liangbi,   
Issue Date: 05 December 2010
 Cite this article:   
Liangbi WANG,Xiaoping GAI,Kun HUANG, et al. A way to explain the thermal boundary effects on laminar convection through a square duct[J]. Front Energ Power Eng Chin, 2010, 4(4): 496-506.
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Liangbi WANG
Xiaoping GAI
Yongheng ZHANG
Xiang YANG
Xiang WU
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doi: 10.2514/1.37067
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doi: 10.1080/10407790190053987
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