Heat transfer augmentation of solar air heater using discrete transverse sinewave corrugations

Abstract

The influence of discretely placed sinewave corrugations on the effective thermal performance of the solar air heater system is presented using numerical methodology. The effect of forward and backward arrangement, normalised wavelength and amplitude on heat transfer enhancement is evaluated for different Reynolds number ranging between 6000 and 24,000. The non-dimensional wavelength and amplitude is varied as 0.0125–0.05 and 0.05–0.2 respectively while the non-dimensional pitch is taken as 1.875. The results show that the forward arrangement pattern of sinewave corrugation provides better thermo-hydraulic performance than the backward arrangement. For any given non-dimensional wavelength, lower non-dimensional amplitude exhibits greater thermal enhancement factor while for a fixed non-dimensional amplitude, the wavelength ratio of 0.025 provides greater thermal enhancement factor. The corrugation having amplitude ratio of 0.1 and wavelength ratio of 0.025 exhibits the highest thermal enhancement factor of 1.69 at Reynolds Number of 6000. It is also observed that, for Reynolds Number lesser than 9000, the configuration of amplitude ratio of 0.1 is found to exhibit higher thermal enhancement factor for any given non-dimensional wavelength. However, for Reynolds Number greater than 9000, the configuration of amplitude ratio of 0.05 is found to exhibit higher thermal enhancement factor for any given non-dimensional wavelength.