Improving heat transfer in the shell & tube heat exchanger with the non-circular cross section tubes

One of the most common used heat exchangers is the shell & tube heat exchanger. It has many usages in the oil and gas, petrochemical and pharmaceutical industries. The heat exchanger is the best which has the highest heat transfer rate with the lowest energy consumption. In this research, we want to increase heat transfer and reduce pressure drop by changing the cross section of tubes. We used tubes with different cross section; circular , ellipse with 0° attack angle and ellipse with 90°attack angle. We study pressure drop and heat transfer coefficient for Re between 3000 to 15000. Then two combined models are examined. Case 1: Circular tubes in the center of the shell and elliptical tubes with 90° attack angle around the shell, case 2: Elliptical tubes with 90° attack angle in the center of the shell and circular tubes around the shell. Which indicates an increase in heat transfer in elliptical tubes, especially elliptical tubes with 90° attack angle compared to the circular, while circular tubes have the lowest pressure drop. However the heat transfer in the case 1 (STHE-CT&ET90°) and the case 2 (STHE-ET90°&CT) increase by 10% and 3% compared to the STHE-CT respectively, it caused increasing the pressure drop.