Detailed analysis of the numerous experimental studies related to the Vortex Heat Transfer Enhancement (VHTE) is beyond this handbook chapter, so only the most useful results for heat exchanger design will be considered here.

A. Flow in plate geometries

Figure 1 illustrates the heat transfer and flow friction on the dimpled plates in the subsonic range of flow velocity. The presented results were obtained for both shallow (h/D < 0.1) and deep (h/D > 0.2) dimples in three values of dimpled density (25%, 50% and 75%) on the test plates.

Figure 1 Heat transfer and friction flow on the dimpled plate (Afanasiev et al., 1993) and test samples

The results (Afanasiev et al., 1993) demonstrated a cost-effective possibility to reach moderate heat transfer enhancement (35–40%) on a flat plate without any significant increase in frictional drag.