Transient conjugated heat transfer in pipes involving two-dimensional wall and axial fluid conduction

Transient conjugated heat transfer in thermally developing laminar flow in thick walled pipes and minipipes with time periodically varying wall temperature boundary condition

“…The amplitude of variation in heat transfer characteristics is becoming too small for very high X values and the results are becoming the same as the results of a similar work Bilir [15], for which the outer wall temperature is suddenly increased by a value of DT as the boundary condition in the downstream region. As to see this and also for the purpose of validation of the present method, Fig.…”

“…12 is given to compare the fluid bulk temperatures for X = 9000, which would be assumed as an extreme case, to those obtained in Ref. [15]. In Fig.…”

“…The finite-difference formulation used in the discretization of the differential equations and the boundary conditions were also used in some previous works, Bilir [14,15,35], Bilir and Ates ß [37], Ates ß et al [38], Darıcı et al [39] and proved to give fast and reliable results in heat transfer problems for thermally developing laminar pipe flows, especially when axial fluid conduction is important, i.e. for low Peclet number flows.…”

“…Conjugated heat transfer problems and fluid axial conduction are also faced in mini or microtubes, because of relatively thick walls, small diameters and therefore low Reynolds and Peclet numbers in flows. Brief literature surveys for laminar pipe or channel flows are given by Shah and London [11] and for conjugate problems by Dorfman [12], Weigand and Gassner [13] and Bilir [14,15].…”

Comparison of turbulence models and CFD solution options for a plain pipe

“…It should also worth that the numerical code of [1] is also given in it. Bilir then reported a solution for transient regime of the previously mentioned problem [3]. This time parameters were increased as wall-to-fluid thermal diffusivity ratio was added into the analysis.…”