Browsing by Author "Mahbubul, I. M."

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Citation - WoS: 139
Citation - Scopus: 160
Effect of nanoparticle shape on the heat transfer and thermodynamic performance of a shell and tube heat exchanger
(PERGAMON-ELSEVIER SCIENCE LTD, 2013) M. M. Elias; M. Miqdad; I. M. Mahbubul; R. Saidur; M. Kamalisarvestani; M. R. Sohel; Arif Hepbasli; N. A. Rahim; M. A. Amalina; Kamalisarvestani, M.; Sohel, M. R.; Mahbubul, I. M.; Elias, M. M.; Amalina, M. A.; Saidur, R.; Miqdad, M.
Nanofluid is a heat transfer fluid that can improve the performance of heat exchanger systems. Different parameters such as particle size shape and volume concentration affect the performance of these systems. The objective of this paper is to study the effect of different nanoparticle shapes (such as cylindrical bricks blades platelets and spherical) on the performance of a shell and tube heat exchanger operating with nanofluid analytically. Boehmite alumina (gamma-AlOOH) nanoparticles of different shapes were dispersed in a mixture of water/ethylene glycol as the nanofluid. The thermodynamic performance of the shell and tube heat exchanger that is used in a waste heat recovery system was analysed in terms of heat transfer rate and entropy generation. Established correlations were used to measure the thermal conductivity heat transfer coefficient and rate and entropy generation of nanofluid. The results show an increase in both the heat transfer and thermodynamic performance of the system. However among the five nanoparticle shapes cylindrical shape exhibited better heat transfer characteristics and heat transfer rate. On the other hand entropy generation for nanofluids containing cylindrical shaped nanoparticles was higher in comparison with the other nanoparticle shapes. However the increased percentage of entropy was below 1%. Therefore this greater entropy generation could be deemed negligible and cylindrical shaped nanoparticles are recommended to be utilized in heat exchanger systems working with nanofluids. (c) 2013 Elsevier Ltd. All rights reserved.
Citation - WoS: 106
Citation - Scopus: 122
Energy- economic- and environmental analysis of a flat-plate solar collector operated with SiO2 nanofluid
(SPRINGER, 2015) M. Faizal; R. Saidur; S. Mekhilef; Arif Hepbasli; I. M. Mahbubul; Mekhilef, S.; Mahbubul, I. M.; Saidur, R.; Hepbasli, A.; Faizal, M.
To overcome the environmental impact and declining source of fossil fuels renewable energy sources need to meet the increasing demand of energy. Solar thermal energy is clean and infinite suitable to be a good replacement for fossil fuel. However the current solar technology is still expensive and low in efficiency. One of the effective ways of increasing the efficiency of solar collector is to utilize high thermal conductivity fluid known as nanofluid. This research analyzes the impact on the performance fluid flow heat transfer economic and environment of a flat-plate solar thermal collector by using silicon dioxide nanofluid as absorbing medium. The analysis is based on different volume flow rates and varying nanoparticles volume fractions. The study has indicated that nanofluids containing small amount of nanoparticles have higher heat transfer coefficient and also higher energy and exergy efficiency than base fluids. The measured viscosity of nanofluids is higher than water but it gives negligible effect on pressure drop and pumping power. Using SiO2 nanofluid in solar collector could also save 280 MJ more embodied energy offsetting 170 kg less CO2 emissions and having a faster payback period of 0.12 years compared to conventional water-based solar collectors.
Citation - WoS: 28
Citation - Scopus: 33
Experimental investigation of the relation between yield stress and ultrasonication period of nanofluid
(Elsevier Ltd, 2016) Islam Mohammed Mahbubul; Rahman Saidur; A. Hepbasli; Muhammad Afifi Amalina; Amalina, M. A.; Mahbubul, I. M.; Saidur, R.; Hepbasli, A.
Nanofluids are the mixtures of solid nanoparticles in liquid. Like most other fluids nanofluids could behave as yield stress fluids which require a certain amount of stress to flow. This flow characteristic may depend on the preparation of nanofluids. This paper investigates the effect of the ultrasonication periods (used during the nanofluid preparation) on the yield stress. The Al2O3 nanoparticle with 0.5 vol.% of solid concentration was added to the distilled water using an ultrasonic horn and applied for different durations from 0 to 5 h. The microstructures of the nanoparticles were observed by transmission electron microscopy. The flow characteristics as the shear stresses at different shear rates (12.23-305.75 s-1) were observed for various temperatures from 10 to 50 °C. The yield stress the flow behavior index and the consistency index were studied using the Herschel-Bulkley rheological model. From this study non-Newtonian flow characteristic was observed. The yield stress decreased with increasing the fluid temperature. At the start of the ultrasonication the yield stress decreased rapidly, however for further ultrasonication it decreased slowly. © 2015 Elsevier B.V. All rights reserved.