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Heat transfer enhancement in helical micro tube heat exchanger using compound technique

The performance of heat exchangers can be altered to perform specific heat-transfer tasks via heat transfer augmentation techniques. These techniques can be divided into two groups that are active and passive. This study involved numerical and experimental investigation of heat transfer enhancement...

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Main Author: Rasheed, Adnan Hameed
Format: Thesis
Language:English
Published: 2021
Subjects:
TP Chemical technology
Online Access:http://eprints.utm.my/id/eprint/101864/1/AdnanHameedPSChE2021.pdf.pdf
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spelling my.utm.1018642023-07-13T02:02:00Z http://eprints.utm.my/id/eprint/101864/ Heat transfer enhancement in helical micro tube heat exchanger using compound technique Rasheed, Adnan Hameed TP Chemical technology The performance of heat exchangers can be altered to perform specific heat-transfer tasks via heat transfer augmentation techniques. These techniques can be divided into two groups that are active and passive. This study involved numerical and experimental investigation of heat transfer enhancement for laminar convective flow using a new type of tube insert, namely a helical microcoil in a heat exchanger with nanofluid. The research used microtube with 1.5 mm diameter, and three types of helical coil, namely circle, oval and elliptical with different diameters and pitches ((10 mm, 14 mm, and 18 mm Different types of nanofluids, Al2O3, CuO, SiO2 and ZnO, were used as work fluids with different nanoparticle diameters (25, 50 and 75 nm) and different volume fractions (1%, 1.5%, and 2%). Water was used as the base fluid. The investigation covered Reynolds number in the range of 200 to 1800. Based on numerical simulation results, for all helical microcoil configurations and different types of nanofluids, experimental work was then developed to determine the optimum geometrical structures and parameters, empirical correlations of Nusselt Number and to formulate the frictional factor. A computational model using the ANSYS-FLUENT 18.0 was developed and evaluated against the experimental findings. It showed that helical microtube curvature swirls were an essential phenomenon to increase heat transfer. It also showed that the heat transfer and friction loss increased as volume fractions of nanofluids and Reynolds number increased while nanoparticle diameter decreased. The numerical and experimental results were compared, where the results showed a good agreement for different parameters. The conclusion is that compared to the straight coil, the helical microtube employment resulted in a clear augmentation in heat transfer with a certain increase in pressure drop. The highest value of the average Nusselt number ratio was 1.35 at Re = 1800 for circle shape with water as coolant. The maximum enhancement in heat transfer using nanofluids was around 11% compared to traditional fluid (water). The best thermal performance factor was 3.15, which was achieved using Al2O3 nanofluid with a volume fraction of 2% at pitch and diameter of 18 mm, and the Reynolds number was 1800. 2021 Thesis NonPeerReviewed application/pdf en http://eprints.utm.my/id/eprint/101864/1/AdnanHameedPSChE2021.pdf.pdf Rasheed, Adnan Hameed (2021) Heat transfer enhancement in helical micro tube heat exchanger using compound technique. PhD thesis, Universiti Teknologi Malaysia. http://dms.library.utm.my:8080/vital/access/manager/Repository/vital:145931
institution Universiti Teknologi Malaysia
building UTM Library
collection Institutional Repository
continent Asia
country Malaysia
content_provider Universiti Teknologi Malaysia
content_source UTM Institutional Repository
url_provider http://eprints.utm.my/
language English
topic TP Chemical technology
spellingShingle TP Chemical technology
Rasheed, Adnan Hameed
Heat transfer enhancement in helical micro tube heat exchanger using compound technique
description The performance of heat exchangers can be altered to perform specific heat-transfer tasks via heat transfer augmentation techniques. These techniques can be divided into two groups that are active and passive. This study involved numerical and experimental investigation of heat transfer enhancement for laminar convective flow using a new type of tube insert, namely a helical microcoil in a heat exchanger with nanofluid. The research used microtube with 1.5 mm diameter, and three types of helical coil, namely circle, oval and elliptical with different diameters and pitches ((10 mm, 14 mm, and 18 mm Different types of nanofluids, Al2O3, CuO, SiO2 and ZnO, were used as work fluids with different nanoparticle diameters (25, 50 and 75 nm) and different volume fractions (1%, 1.5%, and 2%). Water was used as the base fluid. The investigation covered Reynolds number in the range of 200 to 1800. Based on numerical simulation results, for all helical microcoil configurations and different types of nanofluids, experimental work was then developed to determine the optimum geometrical structures and parameters, empirical correlations of Nusselt Number and to formulate the frictional factor. A computational model using the ANSYS-FLUENT 18.0 was developed and evaluated against the experimental findings. It showed that helical microtube curvature swirls were an essential phenomenon to increase heat transfer. It also showed that the heat transfer and friction loss increased as volume fractions of nanofluids and Reynolds number increased while nanoparticle diameter decreased. The numerical and experimental results were compared, where the results showed a good agreement for different parameters. The conclusion is that compared to the straight coil, the helical microtube employment resulted in a clear augmentation in heat transfer with a certain increase in pressure drop. The highest value of the average Nusselt number ratio was 1.35 at Re = 1800 for circle shape with water as coolant. The maximum enhancement in heat transfer using nanofluids was around 11% compared to traditional fluid (water). The best thermal performance factor was 3.15, which was achieved using Al2O3 nanofluid with a volume fraction of 2% at pitch and diameter of 18 mm, and the Reynolds number was 1800.
format Thesis
author Rasheed, Adnan Hameed
author_facet Rasheed, Adnan Hameed
author_sort Rasheed, Adnan Hameed
title Heat transfer enhancement in helical micro tube heat exchanger using compound technique
title_short Heat transfer enhancement in helical micro tube heat exchanger using compound technique
title_full Heat transfer enhancement in helical micro tube heat exchanger using compound technique
title_fullStr Heat transfer enhancement in helical micro tube heat exchanger using compound technique
title_full_unstemmed Heat transfer enhancement in helical micro tube heat exchanger using compound technique
title_sort heat transfer enhancement in helical micro tube heat exchanger using compound technique
publishDate 2021
url http://eprints.utm.my/id/eprint/101864/1/AdnanHameedPSChE2021.pdf.pdf
http://eprints.utm.my/id/eprint/101864/
http://dms.library.utm.my:8080/vital/access/manager/Repository/vital:145931
_version_ 1772811123577323520
score 13.211869

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