NUMERICAL COMPUTATION OF COMPRESSIBLE LAMINAR FLOW WITH HEAT TRANSFER IN THE ENTRANCE REGION OF A PIPE

The authors' research work on pressure drop along gas transmission pipelines raised questions regarding the development length of the corresponding compressible flow and the effect of heat transfer in the entrance region on the pressure drop along the whole length of the pipe. In this paper, laminar, viscous, compressible flow in the entrance region of a pipe is investigated numerically in two dimensions. The numerical procedure is a finite-volume based finite-element method applied on unstructured grids. This combination together with a new method applied for boundary conditions allows accurate computation of the variables in the entrance region. The method is applied to some incompressible cases in order to verify the results. The results are confirmed by previous numerical and experimental research on the developing length in incompressible flow.