Numerical investigation of flow and heat transfer enhancement over a 2-D back-ward facing step with a cylinder mounted near its top corner

A focal point for heat exchanger research is heat transfer enhancement, which is one of the key issues on improving heat exchanger performance and producing more cost effective thermal systems. Numerical investigation of water flows over a two-dimensional backward-facing step that a cylinder mounted near its top corner are presented employing the commercial numerical code FLUENT6.3. Heat transfer enhancement near bottom wall of step by insertion of cylinder is determined. Three different position of cylinder are studied. Streamwise position and size of cylinder were kept constant but the cross-stream position is changed in three steps. Heat transfer, streamline and separation of flow are investigated. Insertion of cylinder in different position has different effect on heat transfer and flow separation downstream of step. When the cylinder is mounted in the highest position the recirculation flow and heat transfer are intensified. So if cylinder is inserted on the proper place its lead to improvement of heat transfer.