Use of turbulators for heat transfer augmentation in an air duct – A review

Energy and material saving considerations, as well as economic incentives, have led toward making effort for producing more efficient heat exchange equipment such as solar air heaters, heat exchangers. In order to enhance the heat transfer rate to flowing air in the duct of solar air heater and heat exchangers various turbulence generators viz. ribs, baffles and delta winglets are considered as an effective technique. Investigators reported on various turbulators in literature for studying heat transfer and friction characteristics in a duct of solar air heaters and heat exchangers. An attempt has been made in this paper to carry out an extensive literature review of various turbulators investigated for enhancing heat transfer and friction in solar air heaters and heat exchangers. The correlations developed for heat transfer and friction factor in solar air heaters and heat exchangers by various investigators have been presented and reviewed.