M.Sc. Tezi Görüntüleme | |||||||||||||||||||||
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| Summary: The hidrodynamically developed, but thermally developing forced convection flow in a pipe is considered including the axial conduction in the wall. The axial conduction in the fluid is neglected. The analytical solutions for the flow and temperature fields are combined with numerical solutions for the conduction in the wall. The effects of the axial heat conduction in the wall on the heat transfer characteristics are determined. Then the problem is considered as a conjugate heat transfer problem. In the analysis, the problem geometry is divided into two sections as unheated pipe outer surface and heated pipe outer surface. For the unheated section, two different thermal boundary conditions are prescribed. The boundary conditions prescribed are a fixed surrounded fluid temperature (equal to the entrance temperature of internal fluid) and a zero outer surface convection coefficient. The effects of Biot number, the conductivities of heated and unheated wall sections together with their lengths and the thickness of the pipe wall on the local variables such as Nusselt number, the wall and the fluid temperatures have been investigated. The results show that thermal conductivity of non-heated wall section, its length, Biot number and the wall thickness have the influence on the local heat transfer variables. It is also concluded that the thermal boundary conditions prescribed for the outer surface of the non-heated section have shown almost the same effect to the heat transfer results.
Keywords: Pipe flow, Forced convection, Axial conduction, Conjugate heat transfer. | |||||||||||||||||||||