CFD Analysis for a Twisted Elliptical Double Tube Heat Exchangers Integrated with a Twisted Tape

Abstract

A numerical investigation into the thermal-hydraulic performance of double elliptical twisted tubes fitted with twisted tape has been conducted. The fluid flow and heat transfer in the twisted double elliptical tubes heat exchanger were modeled utilizing Navier-Stokes, energy, and turbulence equations. The governing equations were resolved using ANSYS Fluent 23.1. Twisting ratios of 5 for twisted tubes and 4 for twisted tape were applied. The Reynolds number was varied within the range of 5000 to 25000. A counter-flow arrangement was established by inputting hot water into the inner tube and cold water into the outer tube. The introduction of twisted tape (TT) resulted in enhanced fluid and centrifugal force mixing near the wall, thereby significantly influencing heat transfer in this region. The study revealed that the heat transfer and performance were notably improved in comparison to a plain double-tube heat exchanger. Furthermore, the heat exchanger's effectiveness was found to increase by 75% at a Reynolds number of 5000.