EXPERIMENTAL INVESTIGATION OF DOUBLE PIPE HEAT EXCHANGER FITTED WITH DIFFERENT GEOMETRIES OF TWISTED TAPE

This paper presents the experimental investigation on passive heat transfer enhancement technique in a double pipe heat exchanger fitted with different geometries of twisted tapes. The heat transfer was analyzed in a swirling flow condition by using twisted tape (TT), perforated twisted tape (PTT), perforated twisted tape with single V-Cut, and perforated twisted tape with double V-Cut under this experiment. The swirl motion created by the twisted tape allows for a large increase in the convective heat transfer coefficient, as well as an increase in the effective flow length. The plain tube has only primary flow but insertion of twisted tape will induce secondary flow that is perpendicular to the primary flow. The magnitude of secondary flow increases and furthermore V- Cut will increase magnitude of secondary flow. Hence the perforated twisted tape with double V-Cut showed higher heat transfer rate among all. Experimental results show the Reynolds number for perforated twisted tape with double V-Cut ranges from 3841.2 to 12203.6, and heat transfer improvement due to perforated twisted tape with double V-Cut became in the range of 1.77 to 2.34 times as compared to plain tube.