Numerical investigation to predict optimum attack angle combination of longitudinal vortex generators in compact heat exchangers for thermo-hydraulic heightened performance

摘要

The current 3-D numerical analysis explores the effect of combinations of rectangular winglet pairs (RWPs) having different attack angles (i.e. 5 degrees, 15 degrees and 25 degrees) along a row of the tube array, on the performance of the fin and tube heat exchanger (FTHE). The considered airside Reynolds number Re ranges from 500 to 900. In total, six combinations of three attack angle vortex generators (VGs) have been numerically analysed namely 5 degrees-15 degrees-25 degrees, 5 degrees-25 degrees-15 degrees, 15 degrees-5 degrees-25 degrees, 15 degrees-25 degrees-5 degrees, 25 degrees-5 degrees-15 degrees and 25 degrees-15 degrees-5 degrees. The performance of the FTHE is represented by area goodness factor. The performance rankings of the FTHEs are also obtained by the MOORA method. Finally, 5 degrees-25 degrees-15 degrees case provides the best thermal hydraulic performance for which heat transfer coefficient (h) is increased by 68.20% at Re = 500 and 81.78% at Re = 900, with a significant pressure drop penalty.