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The current work presents the numerical simulation of turbulent airflow and heat transfer through a rectangular channel along with two trapezoidal baffles which is an important issue for heat exchangers and for that flow phenomena and heat transfer characteristics are need to be identified. Governing equations are solved by FVM and the numerical simulations have been carried out by FLUENT software with the turbulence k-ε model. At Re = 87300, the current work has been validated with the results of Dermitini et al.. Aim of this current work is to study the dynamic behavior of turbulent airflow and heat transfer characteristics for Re ∈ [12000 – 48000]. Moreover, flow structure, normalized velocity profile, normalized skin friction coefficient, normalized friction factor, local and average Nusselt number have also been studied for Re ∈ [12000 – 48000]. For both plane and trapezoidal baffles it has been revealed that pressure drop attains its maximum value at the upstream of the channel and minimum value at the downstream of the channel. Furthermore, it has been concluded that in trapezoidal baffle case normalized flow velocity, normalized skin friction coefficient and friction factor, normalized local and average Nusselt number and thermal enhancement factor becomes more pronounced as compared to plane baffle case. From the present work it has been concluded that in terms of heat transfer trapezoidal baffles will become more convenient rather than the use of plane baffles. [ABSTRACT FROM AUTHOR]

External heat transfer coefficient changing from corridor tube bundle to the reverse cross fluid flow with low-frequency asymmetrical pulsations was analyzed experimentally. The experiments were performed for Reynolds numbers in the tube bundle in the range of 100 ≤ Re ≤ 500 and changing of flow impulses frequency was limited with values 0.125 ≤ f ≤ 0.5Hz, fluid pulsations amplitude in the tube bundle corresponded to 0.5 d ≤ A ≤ 1.2 dmm. A comparison of steady and non-steady conditions was made. The most efficient regime of pulsations in the studied range was found. [ABSTRACT FROM AUTHOR]