Experimental studies on heat transfer augmentation using twisted aluminium taper clips and twisted tapes

Abstract

Heat exchangers have several industrial and engineering applications. The design procedure of heat exchangers is quite complicated, as it needs exact analysis of heat transfer rate and pressure drop estimations apart from issues such as long-term performance and the economic aspect of the equipment. Whenever inserts are used for the heat transfer enhancement, along with the increase in the heat transfer rate, the pressure drop also increases. This increase in pressure drop increases the pumping cost. Thus it’s highly essential not to allow the pressure drop to go beyond a specified value while going for heat transfer enhancement techniques using inserts. The present paper includes various heat transfer augmentation techniques. A literature review of heat transfer augmentation using twisted tapes has been included. Experimental work on heat transfer augmentation using a new kind of insert called TWISTED ALUMINIUM TAPER CLIP (TATC) is carried out. Inserts when placed in the path of the flow of the liquid, create a high degree of turbulence resulting in an increase in the heat transfer rate and the pressure drop. The work includes the determination of friction factor and heat transfer coefficient for various TATC having different twist ratios. The results are compared with twisted tapes having different twist ratios. Four TATC and two twisted tapes having different twist ratios are used in the study. The performance evaluation criterion R1 is found out to clearly depict the enhancement in the heat transfer rate. The results are aptly supported by observation tables and figures.