| Enhancement of heat transfer through various means has been an intense area of research for many years. There are numerous applications where high performance heat exchange is desired. The cooling of electronics, such as microprocessors, is one example. The recent rise in the studies of heat exchange enhancement techniques has also lead to efficient and compact heat exchangers. This research involves the numerical analysis of heat exchange enhancement in a rectangular channel using different types of longitudinal vortex generators (LVG) for a laminar flow. A computational fluid dynamics software package was used to compute the 3-D steady viscous flows with heat transfer. The effects of Reynolds number ranging from 500 to 1000 (laminar flow) are shown from different attack angles of the vortex generators (30° and 45°). Three different types of vortex generators are studied: a delta wing with finite thickness, a trapezoidal delta wing, and a delta winglet pair (also called half delta wing) for a common flow down configuration. The Nusselt number (Nu) is computed and compared with the Nusselt number (Nu0) without the LVG's. The results show that the LVG's effectively enhances the heat transfer in the rectangular channel. In addition, the impact of the LVG's drag and the resulting pressure drop across the channel was quantified. The Darcy's friction factor (f) was computed and compared with the friction factor without LVG's (f0). For each case the performance evaluation parameter ((Nu/ Nu0)/(f/f0)) was computed to gauge the overall efficiency of the configuration. Results are discussed and recommendations for future investigations are given. |
