Effect of Transverse Twisted Baffles on Performance and Irreversibilities in a Duct

Thermal performance and entropy generation are studied for water in a square heat exchanger duct equipped with several transverse twisted baffles to obtain optimal working condition. The influences of twisting angle, nondimensional distance between baffles (D/H), and Reynolds numbers on heat transfer, pressure drop, performance evaluation criteria, and different types of entropy generations are investigated using the finite volume method. The performance evaluation criteria of applying the baffle tend to increase with an increase in the Reynolds number and twisting angle. The performance evaluation criteria at D/H=1.5 and Re=350 increase by about 9% when twisting angle increases from 180 to 540 deg. In addition, the utilization of transverse twisted baffles inside a duct decreases the thermal entropy generation. For example, the thermal entropy generation decreases by about 210% using transverse twisted baffles with D/H=1 and γ=5400 in comparison with an empty duct, without using twisted baffles, at Re=350.