Optimization of the Flow Guiding Fins Configuration and Tube Arrangements in a Shell and Tube Heat Exchanger: Coupling Response Surface Methodology and Cfd

Abstract

In the present study, the flow and heat transfer characteristics around a bundle of cam-shaped tubes have been numerically investigated using the finite volume method (FVM) in laminar and turbulent flows at different Reynolds numbers (Re). To increase heat transfer, flow guide fins have been used in the vicinity of each tube. The design variables include the vertical and horizontal spacing of the tubes, the major and minor diameters of the cam-shaped tube, the distance between the tube and the guide fin, and the angle covered by the guide fin. In both laminar and turbulent flow regimes, the objective functions include the maximum heat transfer and the minimum pressure drop. To optimize the tube layout and the arrangement of the guide fins, the methods of experiment design, the response surface methodology, and the genetic algorithm have been used. The results of this study show that the horizontal spacing between the tube bundles has no significant effect on heat transfer and the objective functions are most sensitive to Re and the angle of the guide fins. Based on the results, the conducting fins in the turbulent flow regime have performed better in increasing heat transfer. In this case, they have improved heat transfer by 20 %, although they have also caused a significant increase in pressure drop. The simulation results of the two-phase flow of water-MWCNT nanofluid in the optimal arrangement of conducting fins show that the heat transfer is improved and the coefficient of performance is greater than 1.