Research Repository

Analysis of the effect of turbulence promoters in hollow fiber membrane distillation modules by computational fluid dynamic (CFD) simulations

Yang, Xing, Yu, Hui, Wang, Rong and Fane, Anthony G (2012) Analysis of the effect of turbulence promoters in hollow fiber membrane distillation modules by computational fluid dynamic (CFD) simulations. Journal of Membrane Science, 415-416. pp. 758-769. ISSN 0376-7388

[img]
Preview
Text
1-Analysis of the effect of turbulence promoters in hollow fiber membrane distillation modules by CFD simulation-text.pdf - Accepted Version

Download (482kB) | Preview
[img]
Preview
Image
1-Analysis of the effect of turbulence promoters in hollow fiber membrane distillation modules by CFD simulation-figures.pdf - Accepted Version

Download (1MB) | Preview

Abstract

As an extended exploration of process enhancing strategies, nine modified hollow fiber modules with various turbulence promoters were designed and modeled using a two dimensional computational fluid dynamic (CFD) heat-transfer model to investigate their potential in improving heat transfer and module performance for a shell-side feed direct contact membrane distillation (DCMD) system. With the aids of turbulence promoters, the feed heat-transfer coefficient hf of the modified modules generally showed much slower decreasing trends along the fiber length compared to the original (unmodified) module. A 6-fold hf enhancement could be achieved by a modified module with annular baffles and floating round spacers. Consistently, the temperature polarization coefficient (TPC) and mass flux distribution curves of these modified modules presented increasing trends and gained an optimal improvement of 57% and 74%, respectively. With the local flow fields and temperature profiles visualized in CFD simulations, it was confirmed that an appropriate selection of turbulence promoters could promote intense secondary flows and radial mixing to improve the shell-side hydrodynamics and enhance heat transfer. Moreover, an increase of flow velocity was used and compared as a conventional approach to improve hydrodynamics. It was found that a well-designed module could bring more significant enhancement for a liquid-boundary layer dominant heat-transfer process. Finally, the hydraulic energy consumption (HEC) caused by the insertion of turbulence promoters or the increase of circulating velocity was compared. Configurations with attached quad spacers or floating round spacers achieved a good compromise between enhanced permeation fluxes and modest HECs. Overall, the TPC decreases with increasing MD coefficient (C) values and operating temperatures; while the thermal efficiency increases dramatically with increasing C and operating temperatures in a MD system.

Item Type: Article
Uncontrolled Keywords: membrane distillation, computational fluid dynamics, turbulence promoters, heat-transfer resistance, temperature polarization, process enhancement
Subjects: Current > FOR Classification > 0904 Chemical Engineering
Historical > Faculty/School/Research Centre/Department > Institute for Sustainability and Innovation (ISI)
Depositing User: Ms Julie Gardner
Date Deposited: 18 Jun 2014 06:25
Last Modified: 19 Jul 2018 07:00
URI: http://vuir.vu.edu.au/id/eprint/25288
DOI: https://doi.org/10.1016/j.memsci.2012.05.067
ePrint Statistics: View download statistics for this item
Citations in Scopus: 49 - View on Scopus

Repository staff only

View Item View Item

Search Google Scholar