Faculty Publications
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Item Experimental analysis on exergy studies of flow through a minichannel using Tio2/Water nanofluids(Elsevier Ltd, 2018) Narendran, G.; Bhat, M.M.; Akshay, L.; Arumuga Perumal, D.A.The present study involves an experimental investigation on rectangular minichannel heat sink for processor cooling of a workstation. The thermal dissipation power of the corresponding system is 25 W. The heat sink is directly in contact to the processor core and subjected to continuous increase in heat flux to the sink depending on the system loading. Water and TiO2 nanofluid with volume fraction of 0.10%, 0.15%, 0.21% and 0.25% is used as the cooling fluid in the experiments with different volume flow rates with a pulsating pump in the range of 210–400 ml/min respectively. The observations were performed with the sink in both horizontal and vertical position in which heat sink is allowed to reach two different temperature limits of 40 °C and 55 °C above which it is subjected to cooling. The Increase in minichannel efficiency was noticed when flowrate increased from 210 ml/min to 280 ml/min with an increment of 53%, but it started to reduce when flow rate approaches 360 ml/min. The outlet exergy and pumping power increases as the flow rate increases to a limit. Furthermore, decrease in efficiency was noticed beyond flow rate of 360 ml/min and the highest outlet exergy was found at a flow rate of 360 ml/min for about 147.52 W. Additionally, exergy analysis is performed for pure fluid under different flow conditions were examined. Further the effect of nanofluid on pressure drop subjected to pulsating flow for varying volume concentrations is also presented. © 2018 Elsevier LtdItem Thermodynamic irreversibility and conjugate effects of integrated microchannel cooling device using TiO2 nanofluid(Springer, 2020) Narendran, G.; Gnanasekaran, N.; Arumuga Perumal, A.P.Thermal management is highly essential for the latest electronic devices to effectively dissipate heat in a densely packed environment. Usually, these high power devices are cooled by integrating micro scale cooling systems. Most of the works reported in the literature majorly concentrate on microchannel heat sink in which the characteristics of friction factor and enhancement of heat transfer are analyzed in detail. However, due to the advent of compact electronic devices a crucial investigation is required to facilitate an amicable environment for the neighboring components so as to improve the reliability of the electronic devices. Henceforth, in the present study a combined experimental and numerical analysis is performed to provide an insight to determine the performance of a copper microchannel integrated with aluminium block using TiO2 nanofluid for different particle configurations. Needless to say, the present study, which also focuses on entropy generation usually attributed to the thermodynamic irreversibility, is very much significant to design an optimum operating condition for better reliability and performance of the cooling devices. © 2019, Springer-Verlag GmbH Germany, part of Springer Nature.Item Investigation on novel inertial minichannel to mitigate maldistribution induced high temperature zones(Elsevier Ltd, 2022) Narendran, G.; Gnanasekaran, G.Axial conduction in channels depends on inlet velocity and thermal conductivity of the working fluid. In the case of parallel channels, axial conduction depends on heat sink configuration and inlet velocity. That at increased flow rates, the parallel channel generates flow maldistribution and develops localized high temperature zones in the heat sink. Effective use of heat sink configuration to mitigate axial conduction is found in the literature; however, the axial conduction effects are not suppressed in the parallel channels. Henceforth, the present study provides experimental and numerical insight to evaluate the potential of ribs and inertial based spillway channels to overcome the above mentioned problems in parallel channels. Especially, four different heat sink concepts were designed using copper material; normal channel, ribbed channel, ribbed inclined, and ribbed lifted. In which normal channel is experimented with and used as a reference, while the remaining channel types were investigated numerically. The factors such as maldistribution, thermal resistance, and pressure drop are considered to evaluate the impact of the ribs on inlet velocity. The ribbed inclined channel was found to perform better than other types and developed a 33 % lower center channel velocity than the normal channel. The temperature near the exit of the ribbed inclined channel was observed to be more even and the entire width of the minichannel was maintained at 47 °C, this trend was not noticed using other configurations. © 2022 Elsevier LtdItem EFFECTS OF NANOREFRIGERANTS FOR REFRIGERATION SYSTEM: A REVIEW(Begell House Inc., 2023) Kumar, A.; Narendran, G.; Arumuga Perumal, A.P.In this article various nanorefrigerants have been critically reviewed towards the performance enhancement of the refrigeration system. Research has been more focused on the different techniques to prepare nanorefrigerants. This paper is an attempt to summarize all aspects of nanorefrigerants such as preparation, thermophysical properties, hydrodynamic study, boiling heat transfer, and performance of nanorefrigerants. It also discusses the effects of different nanoparticles on ther-mophysical properties. Nanorefrigerants are a special category of nanofluid, advanced nanotech-nology-based refrigerants that are stable mixtures of nanoparticles and base fluid, which improve thermophysical properties such as heat transfer and pressure drop and bring compactness to the system. This article presents an overview of improving thermal performance by using different nanoparticle blends with different base refrigerants. Further, influential parameters of nanopar-ticles and thermal performance are discussed. This paper also discusses the effects of different nanoparticles such as Al2O3, TiO2, CuO, carbon nanotubes (CNTs), etc., on thermophysical prop-erties. The present situation requires a robust system and refrigerants for required performance. Some refrigerants cannot be used directly. So, this paper deals with using nanorefrigerants for better system performance such as coefficient of performance (COP) enhancement, compressor work reduction, and energy efficiency. It is seen that the use of nanorefrigerants, or nanotechnology-based refrigerants, results in highly effective cooling and thus enhances the thermophysical properties of refrigeration systems. © 2023 by Begell House, Inc. www.begellhouse.com.Item Experimental investigation on additive manufactured single and curved double layered microchannel heat sink with nanofluids(Springer Science and Business Media Deutschland GmbH, 2023) Narendran, G.; Mallikarjuna, B.; Nagesha, B.K.; Gnanasekaran, N.For the latest high density compact devices, thermal management is crucial for their effective heat dissipation and system reliability. In literature, microchannel heat sink has been established as one of the advanced heat transfer techniques to fulfill the cooling demands of high power electronic applications. However, maldistribution in microchannels causes flow induced high temperature zones (FITZ) which reduces the electrical performance owing to electrical-thermal instability of the integrated chips. One way to mitigate the FITZ is by allowing more coolant inlets in these zones. In the current study, this is achieved by redesigning double layer microchannel heat sink (DMCHS) specific to the FITZ of I-type microchannel configuration using additive manufacturing (AM). Two AM microchannels were tested, one is a single layer microchannel heat sink (MCHS) and another one is a curved double layer microchannel (C-DMCHS). The curved channels were introduced in the bottom channels of C-DMCHS to mitigate FITZ compared to conventional DMCHS. AM microchannels are compared for Nusselt number and friction factor characteristics with the conventional straight channels, and heat treated AM microchannels. From experimental observation, Ti64 3D printed microchannel with Graphene oxide (GO-0.12%) nanofluid developed 75.4% more pressure drop than the Ti64 heat treated microchannel. The results additionally show that the C-DMCHS delivered 26.5% lower FITZ temperature than MCHS. © 2023, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.Item A smart and sustainable energy approach by performing multi-objective optimization in a minichannel heat sink for waste heat recovery applications(Elsevier Ltd, 2023) Narendran, G.; Jadhav, P.H.; Gnanasekaran, N.Minichannel heat sink is widely used in waste heat recovery systems for their compactness and ability to recover heat effectively from high heat flux applications. However, the heat recovery efficiency is constrained by the flow configurations resulting in flow maldistribution. Numerous neural network combined evolutionary algorithms have been used to reduce pressure drop and flow maldistribution factors in the literature. But it is very challenging to assign appropriate weights to these parameters with no physical significance between them for optimization studies. To overcome this, TOPSIS-based optimization studies have been used in the current work to reduce the flow maldistribution factor (ϕ) and increase the Nusselt number (Nu) with ribs and inclined structures. Four Minichannel designs are studied to assess the channel heat recovery efficiency from small-scale incinerators using water and Graphene oxide (GO) nanofluid for three different volume fractions of GO-0.02%, GO-0.07%, and GO-0.12%. The motive is to determine an optimal nanofluid volume fraction and a suitable Minichannel configuration for the given heat flux. The TOPSIS method handles five criteria, including the combination of weightage for the maldistribution factor and Nusselt number. For criteria I ((ϕ)min: (Nu)max = 0.0:1.0) maximum weightage is given to heat transfer, the ribbed channel has gained a higher performance score for GO-0.07% nanofluid volume fraction. For criteria V ((ϕ)min: (Nu)max = 1.0:0.0) maximum weightage is given to maldistribution reduction, the ribbed inclined channel has gained with significantly higher performance score for all the studied nanofluid volume fractions. Further, the study is extended to determine the heat recovery efficiency, and it is found that with the increase in mass flow rate and nanofluid volume fraction, the heat recovery efficiency increases significantly. In particular, the maximum heat recovery efficiency of 66% was obtained for ribbed Minichannel using GO-0.12% nanofluid. © 2023 Elsevier Ltd