Experimental Investigation of Heat Transfer and Pressure drop Characteristics by using twisted tapes of different Twist ratio

Abstract

There are many engineering application that involve heat transfer process, such as solar power collector, thermal power plant, drying agriculture products and many more. All these applications need effective heat transfer. This requires a need of more effective heat transfer with the minimum frictional loss. In view of this an experimental set-up has been built up and experimental investigation has been performed to study the heat transfer and pressure drop characteristics of air flow through circular pipe. Obtained experimental results through smooth tube are validated with Blasius correlation and Petukhov correlation for friction losses and Dittus-Boelter’s correlation, Petukhov’s correlation and Gnielinski’s correlation for Nusselt number. Further, to study the pressure drop and heat transfer characteristics an experimental study has been performed by inserting twisted tapes with and without triangular baffles attached on twisted tapes of twist ratio of 3.8, 3 and 2.6(p itch of 95 mm, 75 mm and 65 mm) and also for Reynolds number ranging from 2600 to 8880. The enhancement heat transfer characteristics were observed with increase in Reynolds number and also with decrease in twist ratio. Friction factor decreases with increase in Reynolds number and also increases with decrease in twist ratio. Further significant enhancement of heat transfer characteristics were observed in twisted tape with triangular baffles compared to twisted tape without baffles.