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 Experimental Investigation on Heat Spreader Integrated Microchannel Using Graphene Oxide Nanofluid(Taylor and Francis Ltd. michael.wagreich@univie.ac.at, 2020) Narendran, G.; Gnanasekaran, N.; Arumuga Perumal, D.A.Thermal design consideration is highly essential for efficient heat dissipation in advanced microprocessors which are subjected to conjugate heat transfer under high heat flux with a minimal area for cooling. Generally, these multicore processors develop a localized high density heat flux referred to as hotspot. The effective use of microchannel in order to mitigate the hotspot is found in literature; however, the flow induced hotspot still exist due to maldistribution of flow inside the microchannel. Henceforth, the present study provides an experimental insight on laminar forced convection in a parallel microchannel heat sink accompanied with 1.2 mm thin copper heat spreader with a surface area of 30 mm2 to effectively migrate the maldistribution flow induced hot spot. The present experimental study provides a profound insight about the hotspot and migration of hotspot to safe zones; as a result, not only the performance of the multi core microprocessor is highly improved but also the reliability of neighboring components is well secured. © 2019, © 2019 Taylor & Francis Group, LLC.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.