Leela Vinodhan | SASTRA University (original) (raw)
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Papers by Leela Vinodhan
Energy Conversion and Management, 2015
Energy Conversion and Management, 2015
Ethylene glycol (EG) plays an important role as coolant in sub-artic and artic regions owing to i... more Ethylene glycol (EG) plays an important role as coolant in sub-artic and artic regions owing to its low freezing point. However one of the limitations of ethylene glycol for energy management is its low thermal conductivity, which can be improved by addition of nanoparticles. In the present work, cupric oxide nanoparticles have been synthesized followed by dispersion in ethylene glycol through extended probe ultrasonication without addition of chemical dispersing agent. Temperature dependency of thermal conductivity of 1 vol% CuO-ethylene glycol nanofluid exhibited a minimum at a critical temperature corresponding to lower thickness of interfacial layers and negligible Brownian motion. The influence of liquid layering on thermal conductivity was predominant at temperatures below critical temperature leading to higher thermal conductivity at lower temperature. Brownian motion-induced microconvection resulted in thermal conductivity increase with temperature above the critical temperature. About 14.1% enhancement in thermal conductivity was obtained at 50°C for 1 vol% CuO-ethylene glycol nanofluid. The viscosity of CuO-ethylene glycol nanofluid was lower than the viscosity of ethylene glycol at temperatures below 50°C and 120°C for 1 vol% and 0.5 vol% CuO-ethylene glycol nanofluids. Our data reveal that the CuO-ethylene glycol nanofluids are better coolants than ethylene glycol for transient cooling under constant heat flux conditions with 11.8% enhancement in heat transfer rate for 1 vol% CuO-ethylene glycol nanofluid. Hence the use of ethylene glycol-based nanofluids is a promising approach for energy management.
Applied Energy, 2014
High thermal conductivity and low-viscous ZnO-ethylene glycol nanofluids prepared. ZnO-ethylene g... more High thermal conductivity and low-viscous ZnO-ethylene glycol nanofluids prepared. ZnO-ethylene glycol-water nanofluids prepared by hierarchical method. Liquid layering and Brownian motion contribute to thermal conductivity enhancement. Improvement in nanofluid cooling performance inline with thermal conductivity rise.
ABSTRACT Computational experiments were carried out on flow and heat transfer in four new microch... more ABSTRACT Computational experiments were carried out on flow and heat transfer in four new microchannel heat sink (MCHS) configurations to compare their performance with the conventional MCHS. The new microchannel heat sinks simulated consist of four compartments with separate coolant inlet and outlet plenum for each compartment. The presence of several regions of developing flow in new designs result in higher Nusselt number and heat transfer rates. The substrate temperature gradients in new configurations are lower than that in conventional MCHS due to better distribution of coolant and recirculation. At the same pumping power, thermal resistances in the new designs are lower than the thermal resistances in conventional MCHS. The design may be further optimized by varying channel dimensions.
Energy Conversion and Management, 2015
Energy Conversion and Management, 2015
Ethylene glycol (EG) plays an important role as coolant in sub-artic and artic regions owing to i... more Ethylene glycol (EG) plays an important role as coolant in sub-artic and artic regions owing to its low freezing point. However one of the limitations of ethylene glycol for energy management is its low thermal conductivity, which can be improved by addition of nanoparticles. In the present work, cupric oxide nanoparticles have been synthesized followed by dispersion in ethylene glycol through extended probe ultrasonication without addition of chemical dispersing agent. Temperature dependency of thermal conductivity of 1 vol% CuO-ethylene glycol nanofluid exhibited a minimum at a critical temperature corresponding to lower thickness of interfacial layers and negligible Brownian motion. The influence of liquid layering on thermal conductivity was predominant at temperatures below critical temperature leading to higher thermal conductivity at lower temperature. Brownian motion-induced microconvection resulted in thermal conductivity increase with temperature above the critical temperature. About 14.1% enhancement in thermal conductivity was obtained at 50°C for 1 vol% CuO-ethylene glycol nanofluid. The viscosity of CuO-ethylene glycol nanofluid was lower than the viscosity of ethylene glycol at temperatures below 50°C and 120°C for 1 vol% and 0.5 vol% CuO-ethylene glycol nanofluids. Our data reveal that the CuO-ethylene glycol nanofluids are better coolants than ethylene glycol for transient cooling under constant heat flux conditions with 11.8% enhancement in heat transfer rate for 1 vol% CuO-ethylene glycol nanofluid. Hence the use of ethylene glycol-based nanofluids is a promising approach for energy management.
Applied Energy, 2014
High thermal conductivity and low-viscous ZnO-ethylene glycol nanofluids prepared. ZnO-ethylene g... more High thermal conductivity and low-viscous ZnO-ethylene glycol nanofluids prepared. ZnO-ethylene glycol-water nanofluids prepared by hierarchical method. Liquid layering and Brownian motion contribute to thermal conductivity enhancement. Improvement in nanofluid cooling performance inline with thermal conductivity rise.
ABSTRACT Computational experiments were carried out on flow and heat transfer in four new microch... more ABSTRACT Computational experiments were carried out on flow and heat transfer in four new microchannel heat sink (MCHS) configurations to compare their performance with the conventional MCHS. The new microchannel heat sinks simulated consist of four compartments with separate coolant inlet and outlet plenum for each compartment. The presence of several regions of developing flow in new designs result in higher Nusselt number and heat transfer rates. The substrate temperature gradients in new configurations are lower than that in conventional MCHS due to better distribution of coolant and recirculation. At the same pumping power, thermal resistances in the new designs are lower than the thermal resistances in conventional MCHS. The design may be further optimized by varying channel dimensions.