Thermal and hydraulic response of turbulent flow inside hexagonal duct fitted with various inserts

Abstract EN

The present work shows the results obtained from experimental investigations of the augmentation of turbulent flow heat transfer in a horizontal hexagonal duct fitted with combined wire coil tabulators and a perforated twisted-tape swirl generator.

Water is used as a working fluid for Reynolds number range between 2480-9922 under constant wall heat flux thermal boundary condition.

In this study, two enhancement heat transfer devices are used.

One is the constant/ periodically varying two wire coil pitch ratio that arranged into two different forms; I-coil (Increasing coil pitch ratio arrangement) and ID-coil (Increasing/decreasing coil pitch ratio arrangement).

The other type of inserts is the perforated twisted- tape with constant twist ratio (Y = 5.3 and PR= 4.5%) that placed at the core of the coil wire.

The experimental data obtained for each enhancement device are compared with those obtained from the plain duct and also from the available literature to ensure the validation of experimental results.

The results show that the heat transfer process have been enhanced with by using combined wire coil and twisted-tape inserts or by using each one alone with compared to plain duct.

The highest thermal performance factor of around 2.18 is found by using ID-coil in common with the twisted-tap .