Heat transfer enhancement through longitudinal vortex generators in compact heat exchangers with flat tubes

The thermal performance of a compact heat exchanger with flat tubes was numerically investigated in a laminar regime by introducing longitudinal vortex generators (LVG) in arrays comprising: 9 alternating, 18 alternating, 18 aligned, 27 alternating and 39 alternating LVG. Vortex generators, in the form of delta winglets with an angle of attack of 35 degrees, were used. For each geometry, the local heat flux, local and global Nusselt number and the friction factor were analysed. The Reynolds number varied between 400 and 2000.