Enhancement of heat transfer rate is one of the crucial factors to be considered in design of heat exchangers. In the present work, experimental investigation is carried in out to achieve the enhancement of heat transfer in the heat exchangers using plain tube, tube with twisted tape inserts and also using the tube with regularly punched twisted tapes. The tape insert with a twisting ratio of 2.37 has been used in the flow passage at flow rates maintained at 4, 6, 8 LPM. The heat transfer rate, friction factor and pressure drop have been calculated for each test case with and without inserts, whereas the range of Reynolds number is 2000<Re<10000, Comparative studies have been carried out for the above mentioned cases using water as well as Nanofluids. While using Nanofluids, the performance of the heat exchangers in terms of the heat transfer and pressure drop are found to be much superior to the performance using distilled water for the same geometric configurations. The rate of heat transfer is found to increase by using inserts and hence modifying the geometry of the flow passage in the duct of the heat exchangers.
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