Solution of flow field and heat transfer problem in tubes having periodically varying cross-sectional area by using control volume method

SUMMARY In this study, numerical solution of flow field and heat transfer problems in tubes having periodically varying cross-sectional area by using control volume method is obtained. A FORTRAN computer program solving axisymetric pipe flow problem has been modified to solve periodically fully developed laminar flow problem. Studies have been carried out for wall-attached and displaced periodic obstacles. Periodic length is chosen as a parameter for the wall-attached case and distance between tube wall and periodic obstacle is chosen as a parameter for displaced obstacle case. For the wall-attached obstacle case, numerical results have been compared with data comes from literature. Some discrepancies appears on results orginated from different assumptions have been discussed. For the wall attached obstacle case, the shortest periodic length causes high friction factor and low Nusselt number. It has been observed that as periodic length increases, the values of /Re and Nusselt number approach the empty tube constant values of 64 and 4.364, respectively. For the displaced obstacles case, as periodic obstacle approaches the centerline of the tube, both friction factor and Nusselt number tend to increase. Key Words : Periodic flow, laminar flow, periodic boundary conditions, periodic obstacles. V