M.Sc Tezi Görüntüleme

      In this study, numerical analysis of conjugate effect of wall and fluid parameters on heat transfer for laminar pipe flow is performed by means of control volume method. A FORTRAN computer code which predicts velocity and temperature field for a axisymetric pipe flow is modified to solve conjugate heat transfer problem.

      Numerical study is carried out under three different boundary conditions for both single and multi-layer pipe wall. The numerical predictions are performed for a single layer and a two layer pipe wall cases . For a single layer pipe wall case, the outer Biot number is chosen as a parameter under the third type boundary condition. For the case of two layer pipe wall, the thermal conductivity ratio of layers, k1/k2, is chosen as a parameter. A comparison with literature is performed for single layer pipe wall case.

      The numerical predictions are in agreement with the results given in the literature. As Biot number increases for the single layer pipe wall case under the third type boundary condition, differences between wall and local mean fluid temperature are also increasing particularly at the inlet section of the solution domain. For the third type boundary condition the local Nusselt number is a approaching to a constant value with increasing axial distance. This constant is also found to be related with Biot number. Similarly, two layer pipe wall case for a constant Biot number, the local Nusselt number is approaching a constant value with increasing axial distance. The constant value is decreasing with increasing thermal conductivity ratio, k1/k2. Additionally, for the constant wall temperature boundary condition for the outer surface of the pipe wall, the thermal conductivity ratio, k1/k2, is not an effective parameter in terms of heat transfer characteristics. For the case of the first type boundary condition the local Nusselt number is approaching to a constant value with increasing axial distance, but unlike the second and third type boundary conditions, this constant value is independent from k1/k2 ratio.

      Key Words: Conjugate heat transfer, Laminar flow, Multi-layer pipe wall