CFD analysis of heat transfer enhancement in a concentric tube counter flow heat exchanger using nanofluids (SiO2/H2O, Al2O3/H2O, CNTs/H2O) and twisted tape turbulators. (2023)

• Record Type: Journal Article
• Authors: Saini, Ruchika; Gupta, Bhupendra; Prasad Shukla, Ambreesh; Singh, Bhavana; Baredar, Prashant; Bisen, Anand
• Is Part Of: Materials today. Volume 76(2023)Part 2
• Page Start: 418
• Page End: 429
• Publication Date: 2023
• Subjects: Concentric Tube Counter Flow Heat Exchanger -- Twisted Tape Turbulators -- Computational Fluid Dynamics -- CNTS, Al2O3, SiO2, Nanofluids -- Heat Transfer Coefficient; Materials science -- Congresses -- Periodicals; 620.1
• DOI: 10.1016/j.matpr.2022.12.044
• Languages: English
• ISSNs: 2214-7853

Abstract

Abstract: A concentric tube, counter flow heat exchanger with nanofluids under turbulent flow conditions has been examined using a computational fluid dynamics model. The proposed model consists of Twisted Tape Turbulators (TTT) on the annular side and inside the tube along with different nanofluids. Twisted Tape Turbulators produce a swirl motion within the fluids to increase heat transfer. Al2 O3 /H2 O, SiO2 / H2 O, and CNTS / H2 O nanofluids (with varying volume concentrations of 1 %, 2 %, and 3 %) with the turbulent flow (Reynold number Re = 2000 to 10000) were considered to determine three major parameters i.e., heat transfer rate (Q), overall heat transfer coefficient (U) and Nusselt number (Nu). This study resulted in 6.03 %, 16.74 %, and 6.74 % enhancement of overall heat transfer coefficient (U) with a 3 % volume concentration of CNTS /H2 O nanofluid, Al2 O3 /H2 O nanofluid, and SiO2 /H2 O nanofluid, respectively, when equated to without twisted tape tabulators. This analysis shows the maximum value of Nusselt number as 143, 136.68 and 140.12 for CNTS /H2 O, Al2 O3 /H2 O, and SiO2 /H2 O, respectively, for the twisted tape tubular arrangement. It is concluded that when using twisted tape turbulator, the heat transfer rate (Q), overall heat transfer coefficient (U), and Nusselt Number (Nu) increase with increasing Reynolds number (turbulent flow conditions) and volume concentrations of nanofluid. Novelty statement: Twisted Tape Turbulators (TTT) arrangement with different concentrations and types of nanofluids combined are infrequent in the study of concentric tube heat exchanger with turbulent flow to obtain enhanced heat transfer.