Investigation of thermal and hydrolic performance of wavy finned heat exchangers by the approximate computational fluid dynamics approach

In this study, the thermal and hydraulic performances of the wavy fin heat exchangers with different wave lengths, wave heights and operating conditions were investigated parametrically via Computational Fluid Dynamics method. The effect of the flow physics on heat transfer and pressure drop characteristics was discussed using flow visualization results such as streamlines, velocity vectors and temperature contours, thermal and hydraulic performance results were reported quantitatively as Colburn j factor, Fanning friction factor f and j/f1/3 ratio. As the wave height increases at constant wave lengths, the pressure drops and the heat transfer coefficients increase due to turbulence production and the extension of the flow length. By decreasing the wave length, the fluid flow could not follow fin walls and flow separations occurred by the effect of an adverse pressure gradient. According to the results obtained from the analyzes, the heat transfer characteristis Colburn j factor generally has higher values where in the models where the wave height h is equal to 1,25 mm Colburn j factor and Fanning friction factor f values decreased when the wave height was decreased to h=0,6 mm. Thermal-hydraulic performance of j/f1/3 results are generally lower for models with wave height h = 1,25 mm. The j/f1/3 values are generally higher when the wave height is reduced to h = 0,6 mm.