Faculty Publications
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Item Numerical analysis of multiple phase change materials based heat sink with angled thermal conductivity enhancer(Elsevier Ltd, 2022) Nedumaran, M.; Gnanasekaran, G.; Hooman, K.Phase change materials (PCM) RT-28HC, RT-35HC, and RT-44HC with three different melting temperatures, 29 °C, 36 °C, and 44 °C, with similar thermal properties, are considered. The PCM is oriented from the left to right side of the heat sink in its increasing order. The fins are attached to the heat sink longitudinally, and its orientation effects are studied low (100–500 W/m2) and high (1000–5000 W/m2) heat fluxes applied on the horizontal bottom surface of the heat sink. A 2D model is developed using ANSYS Fluent 19, and the fin orientation effects are investigated numerically. The orientation of fins at different angles such as 0°, +15°, +30°, +45°, +60°,-15°,-30°,-45°, −60° are considered. The effect of fins on the charging cycle is assessed by comparing a single and double PCM heat sink. Three initial conditions are investigated by altering the initial temperature 300 K, 303 K, and 310 K. At increasing heat input, the negative angled fins possess a higher melting rate. For different initial conditions, −60° provides higher enhancement, and +60° possesses prolonged melting for almost all cases. The performance of a triple PCM design is compared with single and double PCM counterparts under similar conditions. © 2022 The AuthorsItem 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 Comprehensive Analysis of Hybrid Heat Sinks with Phase Change Materials for Both Charging and Discharging Cycles(Taylor and Francis Ltd., 2023) Nedumaran, M.; Gnanasekaran, G.Most of the studies investigated either charging or discharging process in a phase change material (PCM) based heat sink. In this paper, both melting and solidification of n-eicosane filled heat sink is studied numerically. The system filled only with PCM is unable to provide desired performance because of poor thermal conductivity of material. In order to enhance the response time, fins and foams are used in this study. Here, a PCM filled hybrid system of two cases is considered. For case 1, the heat sink with horizontal and vertical fins and for case 2, the heat sink with combination of horizontal fins and metal foams (aluminum) are employed. In case 1, no fin case is compared with rectangular fins and tapered fins. Results show that tapered fins are good for distribution of temperature within the system. In case 2, different filling heights such as 10 mm, 15 mm, and 20 mm with horizontal tapered fins are investigated. From the results, it is observed that the convection is delayed by increasing the filling heights. For solidification cases, 20 mm filling height foam performs better than all other cases. © 2022 Taylor & Francis Group, LLC.