Profit and efficiency boost of triangular vortex-generators by novel techniques

Abstract

Vortex generators augment the thermal efficiency of heat exchangers by creating vortices, swirl flows and subsequent breaking of thermal boundary layer. Practically, the vortex generators commonly install through the central longitudinal direction of the tube. As a negative consequence, the wall-side of the tube, which is the most thermally effective area through the heat exchangers remain in the physical absence of the vortex generator. Hence, present research proposes the use of two semi longitudinal non-central vortex generators (instead of conventional single centrally configuration) as shown in graphical abstract. The best efficacious radial distance (from the central longitudinal line to the place of vortex generators) are evaluated and reported as well. Triangular-winglet type of vortex generator is selected for this 3-D validated numerical study. Interestingly, the results showed that the thermally effective location is neither the central line nor close to the wall. Additionally, application of vortex generator for the tubes with non-circular cross section (ellipsoidal and flat shape cross section with the same hydraulic diameter) is studied in this paper as well for the first time. Moreover, water, air and two different types of Nano-fluids are analyzed as the working fluid with non-central vortex generator. All thermal, frictional, exergetic and economic characteristics of the aforementioned conditions are investigated in present work.