Journal Articles
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Item A review on thermal energy storage using composite phase change materials(Bentham Science Publishers, 2018) Chavan, S.; Gumtapure, V.; Arumuga Perumal, D.A.Background: This paper intends to provide the elementary understanding about the development of thermal energy storage systems. Reviews of storage system performance are carried out from various characterization studies, experimental work, numerical investigations and patents. Several techniques employed to enhance the thermal performance have been reviewed and discussed. Composite phase change materials are the best alternative to achieve the cost feasibility in thermal energy storage systems without compromising the storage capacity. Objective: The purpose of this study is to give an outline and history of the thermal energy storage systems and enlighten the techniques used for storage density enhancement without significant modifications in the design. Methods: In this study, three methods such as, characterization studies, experimental work, numerical investigations and patents. It also addresses many research articles and recent patents on the thermal storage systems, various techniques adopted and applications of such systems. Results: Composite phase change materials are the best alternative to achieve the cost feasibility in thermal energy storage systems without compromising the storage capacity. Carbon based nanoparticles show excellent properties in the composite phase change materials. Conclusion: Composite phase change materials have greater potential for thermal energy storage applications and especially carbon-based nanoparticles like graphene, graphene oxide, carbon nanotubes, fullerene, graphite, graphite oxide, extracted graphite etc., are greatly enhancing the thermo-physical properties of composite phase change materials. Combination of paraffin-based phase change materials and carbon-based nanoparticles can be used for the future thermal energy storage applications. © 2018 Bentham Science Publishers.Item Thermal energy storage in concrete: A comprehensive review on fundamentals, technology and sustainability(Elsevier Ltd, 2024) Barbhuiya, S.; Das, B.B.; Idrees, M.This comprehensive review paper delves into the advancements and applications of thermal energy storage (TES) in concrete. It covers the fundamental concepts of TES, delving into various storage systems, advantages, and challenges associated with the technology. The paper extensively explores the potential of concrete as a medium for thermal energy storage, analysing its properties and different storage methods. Additionally, it sheds light on the latest developments in concrete technology specifically geared towards thermal energy storage. The evaluation section discusses measurement techniques, experimental evaluations and performance metrics. Environmental and economic aspects, including sustainability and cost analysis, are thoughtfully addressed. The review concludes by underlining the significance of thermal energy storage in concrete, emphasizing its role in efficient energy management and the promotion of sustainable practices. © 2023 The AuthorsItem Heat transfer during quenching of modified and unmodified gravity die-cast A357 cylindrical bars(2006) Prabhu, K.; Hemanna, P.Heat transfer during quenching of chill-cast modified and unmodified A357 Al-Si alloy was examined using a computer-aided cooling curve analysis. Water at 60°C and a vegetable oil (palm oil) were used as quench media. The measured temperatures inside cylindrical probes of the A357 alloy were used as inputs in an inverse heat-conduction model to estimate heat flux transients at the probe/quenchant interface and the surface temperature of the probe in contact with the quench medium. It was observed that modified alloy probes yielded higher cooling rates and heat flux transients. The investigation clearly showed that the heat transfer during quenching depends on the casting history. The increase in the cooling rate and peak heat flux was attributed to the increase in the thermal conductivity of the material on modification melt treatment owing to the change in silicon morphology. Fine and fibrous silicon particles in modified A357 probes increase the conductance of the probe resulting in higher heat transfer rates. This was confirmed by measuring the electrical conductivity of modified samples, which were found to be higher than those of unmodified samples. The ultrasound velocity in the probes decreased on modification. ©ASM International.Item Effect of thermal contact heat transfer on solidification of Pb-Sn and Pb-free solders(Elsevier Ltd, 2007) Chellaih, T.; Kumar, G.; Prabhu, K.N.The effect of thermal contact heat transfer on the solidification of spherical droplets of four solder alloys, namely, Sn-37Pb, Sn-9Zn, Sn-0.7Cu and Sn-3.5Ag, was studied using SOLIDCAST simulation package. A significant drop in the arrest time was observed for increase in heat transfer coefficient from 1000 to 2000 W/m2 K. Effect of contact conductance and thermal diffusivity of solder alloys on arrest time is quantified by the power relation, ? = m(?{symbol})n where ? and ?{symbol} are defined as arrest time and heat transfer parameters, respectively. Experiments were also carried out to investigate the effect of cooling rate on solidification behaviour of the solder alloys used in simulation. The results indicated the significant effect of mould material on interfacial heat flux and metallurgical microstructure. © 2005 Elsevier Ltd. All rights reserved.Item Synthesis of copper nanofluids using ascorbic acid reduction method via one step solution phase approach(ASTM International, 2012) Shenoy, S.U.; Nityananda Shetty, A.N.A simple one step solution phase approach to synthesize copper nanofluids has been developed, involving simultaneous in situ synthesis of nanoparticles and their dispersion in the base fluid. Copper nitrate has been reduced using ascorbic acid in ethylene glycol under thermal as well as microwave conditions. Sodium lauryl sulfate has been used to control the size of the particle as well as to act as a stabilizing agent. The effect of ratio of the reactants, pH, power of microwave, reaction time, and dilution on the size of the particles has been studied using X-ray diffraction, transmission electron microscopy, and field-emission scanning electron microscopy. The characterization of the fluids has also been done using Fourier transform infrared spectrometry, ultraviolet-visible spectroscopy, selected area electron diffraction, and energy dispersive X-ray analysis. The thermal conductivity and viscosity of the fluid were also measured at various particle concentrations. The copper particles in the fluid were found to have size less than 50nm and were well dispersed in the fluid. Thus this method was found to preserve the advantages of the polyol process and aqueous chemical reduction method as well. The fluid was stable up to 5 weeks under stationary conditions at room temperature. This method employs fast, inexpensive, extendible process for the synthesis of copper nanofluids and also overcomes the drawbacks of two step process. Copyright © 2012 by ASTM International.Item Synthesis of copper nanofluids using ascorbic acid reduction method via one step solution phase approach(2012) Shenoy, S.U.; Nityananda Shetty, A.N.A simple one step solution phase approach to synthesize copper nanofluids has been developed, involving simultaneous in situ synthesis of nanoparticles and their dispersion in the base fluid. Copper nitrate has been reduced using ascorbic acid in ethylene glycol under thermal as well as microwave conditions. Sodium lauryl sulfate has been used to control the size of the particle as well as to act as a stabilizing agent. The effect of ratio of the reactants, pH, power of microwave, reaction time, and dilution on the size of the particles has been studied using X-ray diffraction, transmission electron microscopy, and field-emission scanning electron microscopy. The characterization of the fluids has also been done using Fourier transform infrared spectrometry, ultraviolet-visible spectroscopy, selected area electron diffraction, and energy dispersive X-ray analysis. The thermal conductivity and viscosity of the fluid were also measured at various particle concentrations. The copper particles in the fluid were found to have size less than 50nm and were well dispersed in the fluid. Thus this method was found to preserve the advantages of the polyol process and aqueous chemical reduction method as well. The fluid was stable up to 5 weeks under stationary conditions at room temperature. This method employs fast, inexpensive, extendible process for the synthesis of copper nanofluids and also overcomes the drawbacks of two step process. Copyright © 2012 by ASTM International.Item Effect of boundary heat transfer coefficient and probe section size on cooling curves during quenching(ASTM International, 2012) Ramesh, G.; Prabhu, K.N.In the present work the effect of boundary heat transfer coefficient and section size of quench probe material on cooling curves was investigated by using finite difference heat transfer based SolidCast software. Simulations were carried out at different combinations of heat transfer coefficient and quench probe diameter and thermal history at the geometric center of the probe was estimated to generate cooling curves. Simulation results show that both boundary heat transfer coefficient and quench probe diameter had a significant effect on the average cooling rate. A relationship between Grossmann quench severity (H), thermal conductivity of material, size of the probe, and average cooling rate was established. By using this model, for a known quench medium, probe size, and material it is possible to predict the average cooling rate of the probe. On the other-hand, for a given material and required cooling rate, cooling severity required from the quench media could be predicted and accordingly an appropriate quench medium can be selected. © 2012 by ASTM International.Item A facile one step solution route to synthesize cuprous oxide nanofluid(InTech Europe info@sagepub.co.uk, 2013) Sandhya, S.U.; Nityananda, S.A.A cuprous oxide nanofluid stabilized by sodium lauryl sulfate, synthesized by using the one step method, has been reported. Nanofluids were synthesized by using a wellcontrolled surfactant-assisted solution phase synthesis. The method involved reduction of copper acetate by glucose in a mixture of water and ethylene glycol serving as the base fluid. The synthesized fluid was characterized by X-ray and electron diffraction techniques, in addition, transmission and field emission microscopic techniques and Fourier transform infra red spectroscopic analysis was undertaken. The rheological property, as well as the thermal conductivity of the fluid, were measured. The variation of reaction parameters considerably affected the size of the particles as well as the reaction rate. The uniform dispersion of the particles in the base fluid led to a stability period of three months under stationary state, augmenting the thermal conductivity of the nanofluid. The method is found to be simple, reliable and fast for the synthesis of Newtonian nanofluids containing cuprous oxide nanoparticles. © 2013 Sandhya and Nityananda.Item Dimensionless cooling performance parameter for characterization of quench media(2013) Ramesh, G.; Prabhu, K.The effect of varying thermal properties and boundary heat transfer coefficients on temperature profiles inside cylindrical quench probes was simulated during immersion cooling. The results of simulation indicated that, for assessment of the cooling performance of the quench media, the ratio of the quench probe diameter to its thermal conductivity should be less than 0.0005 m2K/W. A simple dimensionless cooling parameter (D 2CR/??T) was proposed to assess the cooling performance of quench media. © 2013 The Minerals, Metals & Materials Society and ASM International.Item Effect of thermal conductivity and viscosity on cooling performance of liquid quench media(Maney Publishing Suite 1C, Joseph's Well, Hanover Walk Leeds LS3 1AB, 2014) Ramesh, G.; Prabhu, K.In this present work, the effect of the thermophysical properties of quenchants on its cooling performance was investigated. Water, brine solutions, polymer solutions and mineral oils were chosen to have quench media with varying thermophysical properties. Cooling curve analyses were carried out by using standard ISO/DIS 9950 quench probe. Grossmann H quench severity of the quench media was determined from the relation of H and cooling rate. Cooling curve analysis results showed that the change in thermophysical properties of the quench media had significant effect on the cooling history of the quench probe. The viscosity of the quenchant used for immersion quenching is the most important factor that controls the cooling performance of the quenchant compared to thermal conductivity of the quench medium. © 2014 IHTSE Partnership.