Effect of Wave Amplitude on Thermal Performance of the Wavy-Fin-Plate Compact Heat Exchanger: A Numerical Study and Presentation of New Correlations

One of the most effective geometrical parameters on performance of the wavy fin plate compact heat exchanger (CHE) is the wave amplitude. New correlations are required to consider the wave amplitude for designing this type of exchangers. In this paper, the effect of wave amplitude on Colburn factor (j) and Fanning friction factor (f) was investigated. The J factor is a criterion of heat transfer rate and the f factor is proportional to pressure drop. In this study, the three dimensional computational fluid dynamics simulation of an exchanger’s wave channel was performed. The channel’s height was 8 mm, its pitch was 2 mm, and its lengths were 43.2 and 64.8 mm. The published experimental data of this channel with wave amplitude of 1.5 mm is available. Therefore, the simulation was firstly carried out using this wave amplitude in Reynolds number range of 600 to 6500. The simulation results were in good agreement with the experimental data and the mean error values obtained for j and f were 7% and 4% respectively. In the second step, the channel simulation was implemented using wave amplitudes of 0.5, 1, 2, 2.5, and 3 mm. The results indicated that the wave amplitude is effective on j and f factors. Both factors increase with increasing the wave amplitude in laminar and turbulent flows; however, the wave amplitude is more effective on the f factor. Using the multiple curve fitting method, two correlations were obtained for j and f versus Reynolds number and different geometric dimensions of the wavy channel, especially the wave amplitude. In order to determine these correlations, previous experimental and calculated data and new calculated results were applied and the effect of wave amplitude was considered. These equations are useful for wavy fin plate compact heat exchanger using air as the cooling fluid.