Fluid Flow and Heat Transfer in a Heat Exchanger Channel with Short-Length Twisted Tape Turbulator Inserts

Abstract

The thermohydraulic characteristics of turbulent flow of air (Pr 0.7) through circular tube with short-length and full-length twisted-tape turbulators inserts have been studied experimentally. Also, heat transfer performance for different values of the twist ratio, tape thickness ratio and diameter ratio are investigated for Reynolds numbers within the range 6000–20,000. The full-length twisted tape enhances heat transfer more than those of short-length twisted tapes. Heat transfer and pressure drop tests were carried out in brass channels. The channel with twisted tape inserts specifies that the use of tapes augments heat transfer mostly, which is complemented by a greater friction penalty. The thermohydraulic performance of the problem under study has been assessed. It is observed that by using full-length twisted tape at constant pumping power, up to 27% heat duty rises in comparison with short-length twisted tape. Similarly, by using full-length twisted tape at heat duty, up to 33% pumping power increases in comparison with short-length twisted tape.