A numerical investigation is conducted to examine laminar periodic flow and heat transfer characteristics in a square channel fitted with 45? inclined baffle inserted periodically in the channel.Air is the working fluid with the flow rate in terms of Reynolds number based on the channel hydraulic diameter ranging from 100 to 1000.The utilization of the 45? inclined baffles is to create counter-rotating vortex flows having a significant influence on the flow laminar intensity

enhancing heat transfer in the channel.Effects of different pitch ratios(PR=L/H)with a baffle height ratio(BR=b/H)of 0.2 on heat transfer and pressure loss in the channel were examined.The results show that the baffles create pair of vortex flows

inducing impingement flows on a side and the upper and lower walls and increasing heat transfer rate over the test channel substantially.An analysis on the averaged Nusselt number ratio

friction factor ratio and thermal enhancement factor with the change of pitch ratio and Reynolds number is used for establishing the corresponding criterion correlation.The computation reveals that the optimum thermal performance enhancement factor of about 3.0 is found at PR=0.5.