Numerical Investigations of Laminar Air Flow and Heat Transfer Characteristics in a Square Channel Inserted with Discrete X-V Baffles (XVB)

Abstract

Thermal performance enhancement in a square channel heat exchanger (HX) using a passive technique is presented.Vortex turbulator insertion in a square channel HX as a passive technique is selected for thermal improvement.The vortex turbulator of interest is discrete X-V baffles (XVB).The discrete XVBs are inserted in the square channel with the main aim to generate vortex flow.The vortex flow generated can support to enhance convective heat transfer coefficient and also enhance HX performance.Effects of baffle configuration (type A and B), baffle size (w/H = 0.05, 0.10, 0.15 and 0.20), baffle distance (e/H = 1, 1.5 and 2) and flow direction (±x air flow paths) on fluid flow and thermal topologies are numerically investigated by using a commercial code.As shown by the numerical results, the predicted flow configuration with the discrete XVB insertions, which include impinging and vortex streams, is found through the HX channel.The perturbing thermal boundary layer and greater air blending are also found through the HX channel inserted with the discrete XVB.These mechanisms promote to augment a convection heat transfer coefficient, heat transfer rate and rise thermal potentiality.The maximum Nusselt number of the channel with the baffles inserted is 11.01 times upper than that of the smooth channel, while the greatest thermal performance factor (TPF) is observed to be around 3.45.