Thermal performance improvement of a rectangular channel using different arrangements of V-shaped baffles

One solution to increase the heat transfer in a channel of solar air heaters is adding baffles along the air path. In this study, investigation on the characteristics of heat transfer and fluid flow in a rectangular channel with V-shaped baffles located at the top and bottom walls of the heater is studied. The parameters such as baffle arrangement, baffle pitch and baffle height at different Reynolds numbers are examined. Nusselt number, friction factor and thermal performance coefficient have been investigated as output parameters. The governing equations include continuity, momentum and energy. The standard k-ԑ model is used to simulate the turbulence model in the channel. The results indicate that by increasing the number of baffle rows, the airflow velocity increases, flow becomes more turbulent and consequently the heat transfer increases. In the study of different baffle pitches, it was found that the channel with baffles with a step of 50 mm has the highest thermal performance coefficient. Also, by increasing the baffle height at a constant heat transfer surface, due to the increase in the velocity of the flow passing through the baffles, the coefficient of performance increases by about 28%.