The Experts below are selected from a list of 60177 Experts worldwide ranked by ideXlab platform
Mohammad A Alim - One of the best experts on this subject based on the ideXlab platform.
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analyses of exergy efficiency and Pumping Power for a conventional flat plate solar collector using swcnts based nanofluid
Energy and Buildings, 2014Co-Authors: Zafar Said, R Saidur, N A Rahim, Mohammad A AlimAbstract:Abstract This paper theoretically analyses entropy generation, heat transfer enhancement capabilities and pressure drop for a flat-plate solar collector operated with single wall carbon nanotubes (SWCNTs) based nanofluids as an absorbing medium. Specific heat (Cp) of the nanofluid was measured using a PerkinElmer DSC 4000, and a density meter was used to measure the density of the nanofluid. Second law based exergy analysis was carried out to evaluate the efficiency of the flat plate collector. It is observed that the SWCNTs nanofluid reduced the entropy generation by 4.34% and enhance the heat transfer coefficient by 15.33% theoretically compared to water as an absorbing fluid. Pumping Power penalty of nanofluid operated solar collector found to be 1.20% higher than the water as a working fluid.
V Muthusamyswami - One of the best experts on this subject based on the ideXlab platform.
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experimental investigation on heat transfer and Pumping Power of forced circulation flat plate solar collector using heat transfer enhancer in absorber tube
Applied Thermal Engineering, 2017Co-Authors: K Balaji, S Iniyan, V MuthusamyswamiAbstract:Abstract This paper experimentally investigates the performance of an absorber tube with heat transfer enhancer in solar flat plate water heater. The objective of the work is to increase the convective heat transfer by reducing the cross sectional area between the absorbing fluid and inner wall of the tube. The heat transfer enhancers are frictionally engaged with the inner side of the tube wall, and it is kept in the axial flow direction of the fluid flow path. Two types of heat transfer enhancers, namely, rod heat transfer enhancer and tube heat transfer enhancer, are used herein and compared with each other. The efficiency, heat transfer coefficient and Pumping Power for flat plate solar collector were analyzed, and it was found that, the rod heat transfer enhancer provides higher heat transfer with a small increase in Pumping Power than tube heat transfer enhancer and plain tube flat plate solar collector. The maximum increase in Pumping Power is 1.081 and 1.044 times higher for rod and tube heat transfer enhancers respectively, compared to plain tube solar collector.
Wenhua Yu - One of the best experts on this subject based on the ideXlab platform.
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Pumping Power of nanofluids in a flowing system
Journal of Nanoparticle Research, 2011Co-Authors: J. L. Routbort, Elena V. Timofeeva, Dileep Singh, Wenhua YuAbstract:Nanofluids have the potential to increase thermal conductivities and heat transfer coefficients compared to their base fluids. However, the addition of nanoparticles to a fluid also increases the viscosity and therefore increases the Power required to pump the fluid through the system. When the benefit of the increased heat transfer is larger than the penalty of the increased Pumping Power, the nanofluid has the potential for commercial viability. The Pumping Power for nanofluids has been considered previously for flow in straight tubes. In this study, the Pumping Power was measured for nanofluids flowing in a complete system including straight tubing, elbows, and expansions. The objective was to determine the significance of two-phase flow effects on system performance. Two types of nanofluids were used in this study: a water-based nanofluid containing 2.0–8.0 vol% of 40-nm alumina nanoparticles, and a 50/50 ethylene glycol/water mixture-based nanofluid containing 2.2 vol% of 29-nm SiC nanoparticles. All experiments were performed in the turbulent flow region in the entire test system simulating features typically found in heat exchanger systems. Experimental results were compared to the Pumping Power calculated from a mathematical model of the system to evaluate the system effects. The Pumping Power results were also combined with the heat transfer enhancement to evaluate the viability of the two nanofluids.
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Heat transfer to a silicon carbide/water nanofluid
International Journal of Heat and Mass Transfer, 2009Co-Authors: Wenhua Yu, Elena V. Timofeeva, David S. Smith, Dileep Singh, David M. France, J. L. RoutbortAbstract:Heat transfer experiments were performed with a water-based nanofluid containing 170-nm silicon carbide particles at a 3.7% volume concentration and having potential commercial viability. Heat transfer coefficients for the nanofluid are presented for Reynolds numbers ranging from 3300 to 13,000 and are compared to the base fluid water on the bases of constant Reynolds number, constant velocity, and constant Pumping Power. Results were also compared to predictions from standard liquid correlations and a recently altered nanofluid correlation. The slip mechanisms of Brownian diffusion and thermophoresis postulated in the altered correlation were investigated in a series of heating and cooling experiments.
J. L. Routbort - One of the best experts on this subject based on the ideXlab platform.
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Pumping Power of nanofluids in a flowing system
Journal of Nanoparticle Research, 2011Co-Authors: J. L. Routbort, Elena V. Timofeeva, Dileep Singh, Wenhua YuAbstract:Nanofluids have the potential to increase thermal conductivities and heat transfer coefficients compared to their base fluids. However, the addition of nanoparticles to a fluid also increases the viscosity and therefore increases the Power required to pump the fluid through the system. When the benefit of the increased heat transfer is larger than the penalty of the increased Pumping Power, the nanofluid has the potential for commercial viability. The Pumping Power for nanofluids has been considered previously for flow in straight tubes. In this study, the Pumping Power was measured for nanofluids flowing in a complete system including straight tubing, elbows, and expansions. The objective was to determine the significance of two-phase flow effects on system performance. Two types of nanofluids were used in this study: a water-based nanofluid containing 2.0–8.0 vol% of 40-nm alumina nanoparticles, and a 50/50 ethylene glycol/water mixture-based nanofluid containing 2.2 vol% of 29-nm SiC nanoparticles. All experiments were performed in the turbulent flow region in the entire test system simulating features typically found in heat exchanger systems. Experimental results were compared to the Pumping Power calculated from a mathematical model of the system to evaluate the system effects. The Pumping Power results were also combined with the heat transfer enhancement to evaluate the viability of the two nanofluids.
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Heat transfer to a silicon carbide/water nanofluid
International Journal of Heat and Mass Transfer, 2009Co-Authors: Wenhua Yu, Elena V. Timofeeva, David S. Smith, Dileep Singh, David M. France, J. L. RoutbortAbstract:Heat transfer experiments were performed with a water-based nanofluid containing 170-nm silicon carbide particles at a 3.7% volume concentration and having potential commercial viability. Heat transfer coefficients for the nanofluid are presented for Reynolds numbers ranging from 3300 to 13,000 and are compared to the base fluid water on the bases of constant Reynolds number, constant velocity, and constant Pumping Power. Results were also compared to predictions from standard liquid correlations and a recently altered nanofluid correlation. The slip mechanisms of Brownian diffusion and thermophoresis postulated in the altered correlation were investigated in a series of heating and cooling experiments.
Kyosung Choo - One of the best experts on this subject based on the ideXlab platform.
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heat transfer characteristics of impinging air jets under a fixed Pumping Power condition
International Journal of Heat and Mass Transfer, 2010Co-Authors: Kyosung ChooAbstract:Heat transfer characteristics of an impinging air jet are experimentally investigated under a fixed Pumping Power condition. The effects of dimensionless Pumping Power (Ppump∗=1.4×1010–6.7×1012) on the Nusselt number are considered. The focus is on cases where the nozzle-to-plate spacing is equal to or less than one nozzle diameter (H/d ⩽ 1.0). The results show that the Nusselt number is independent of the nozzle-to-plate spacing under fixed Pumping Power conditions, while the Nusselt number increases with decreasing the nozzle-to-plate spacing under fixed flow rate conditions. Based on the experimental results, new correlations for the stagnation and average Nusselt numbers of the impinging jet are developed as a function of the Pumping Power alone.
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Air Jet Impingement Heat Transfer at Low Nozzle-to-Plate Spacings Under a Fixed Pumping Power Condition
Volume 2: Theory and Fundamental Research; Aerospace Heat Transfer; Gas Turbine Heat Transfer; Computational Heat Transfer, 2009Co-Authors: Kyosung ChooAbstract:Heat transfer characteristics of an impinging air jet are experimentally investigated under a fixed Pumping Power condition. The effects of dimensionless Pumping Power on the Nusselt number are considered. The focus is on cases where the nozzle-to-plate spacing is equal to or less than one nozzle diameter. The results show that the Nusselt number is independent of the nozzle-to-plate spacing under fixed Pumping Power conditions, while the Nusselt number increases with decreasing the nozzle-to-plate spacing under fixed flow rate conditions. Based on the experimental results, new correlations for the stagnation and average Nusselt numbers of the impinging jet are developed as a function of the Pumping Power alone.Copyright © 2009 by ASME
