The Enhancement of Turbulent Heat Transfer of Pipe Flow with a Pair of Twisted Tapes

Abstract

The characteristics of heat transfer have been experimentally investigated for a circular pipe in which a pair of twisted tapes was inserted to enhance convective and radiative heat transfer. The local and average heat transfer coefficients, and pressure drop were measured for three kinds of pitch lengths. The performance of the present promoter was evaluated based on the area of heat transfer under the condition of the same flow rate, pressure drop and transferred heat. It was found in the case of room temperature that the heat transfer area can be reduced to about 30% less than a smooth pipe. In the case of high temperature, about 450°C, the heat transfer rate was further increased by a factor of 1.5 due to the effect of radiation between the pipe wall and the promoter.