Open AccessTurbulent heat transfer enhancement in tubular heat exchangers with different twisted tape inserts
Author(s) -
Sadman Hassan Labib,
M. R. A. Himel,
Jabbar Ali,
A.R. Mim,
Mohammad Jobayer Hossain,
Arghya Ghosh,
Abir Goswami
Publication year - 2021
Publication title -
journal of mechanical engineering and sciences
Language(s) - English
Resource type - Journals
eISSN - 2231-8380
pISSN - 2289-4659
DOI - 10.15282/jmes.15.3.2021.14.0658
Subject(s) - nusselt number , heat transfer , concentric tube heat exchanger , turbulence , materials science , dynamic scraped surface heat exchanger , heat exchanger , micro heat exchanger , heat transfer enhancement , mechanics , reynolds number , plate heat exchanger , thermodynamics , heat transfer coefficient , enhanced heat transfer , critical heat flux , physics
Experimental and numerical analyses are carried out to investigate the influence of twisted tape inserts on the heat transfer and the flow behavior in double tube heat exchangers. First, all the performance factors, namely the Nusselt number, friction factor, and thermal performance factor, were studied for a basic heat exchanger (BHE). Afterwards, twisted tapes with three different twist ratios (7.5, 6, and 4.5) were inserted inside the inner tube of the BHE, which resulted in three different modified heat exchangers (MHEs). For the numerical study, a 3D numerical model is developed with the k-ε RNG turbulent model to visualize the flow and the heat transfer behavior inside the heat exchangers. In both studies, turbulent flow field is maintained, ranging Reynolds number from 15000 to 50000. From the experimental result, an enhanced heat transfer, characterized by the performance factors, is found for all the MHEs compared to the BHE. The most enhanced thermal performance factor is achieved for the MHE with the lowest twist ratio. Finally, a good agreement between obtained numerical and experimental results reveals that the present numerical model can reliably predict the flow and heat transfer behavior in double tube heat exchangers.