Abstract
Efficient heat transfer in industry and commercial sectors is vital if saving energy is a concern. Heat exchangers are devices that are built for this aim. Here, cross-flow heat exchangers are analyzed to increase the heat transfer rate and reduce the pressure drop simultaneously. Cross-flow heat exchangers possess a simple geometry, yet a complex flow behavior. The reason lies behind the von Karman vortex structures that are created due to the presence of an initial row of tubes. This will affect the next stages of tube bundles and form an intricate thermo-hydraulic interplay. In general, there are various passive techniques to enhance the efficiency of cross-flow heat exchangers such as tube orientation, adding vortex generators, and addition of fins. Each technique has its strengths and weaknesses that try to address them individually in this chapter.