Experimental investigation of the different kinds of vortex generator effects on a air-water finned tube heat exchanger using exergy analysis

In this study a fin-tube heat exchanger with different kinds of vortex generator has been studied experimentally، using exergy method. Three kinds of vortex generator have been employed: 1-Tetrahedral wedge shape 2-Rectangular block shape 3-Triangular winglet shape. In this research we used a wind tunnel to produce wind flow over heat exchanger. hot water was circulating with the steady volume flow rate and temperature range of 44 to 68 celsius in the system. The results shows that use of these VGs will decrease the air side irreversibility to heat transfer ratio (ASIHR) in the air region and for a heat exchanger with block shape VGs، this reduction is more than the other two types. This could be due to the irreversibility decline in the air region because of lower mean temperature difference of water and air and the heat transfer conditions improvement. To reveal the effects of various VGs on heat exchanger performance with respect to reducing ASIHR، a quantity is used namely performance of vortex generator (PVG). The results showed that PVG values are in the range of less than 5% for wedge-shaped VG''s to over 35% for block-shaped VG''s. Which represents the good effects of VGs especially block-shaped ones on the heat exchanger performance.