Faculty Publications
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Item Numerical consideration of LTNE and darcy extended forchheimer models for the analysis of forced convection in a horizontal pipe in the presence of metal foam(American Society of Mechanical Engineers (ASME), 2021) Jadhav, P.H.; Gnanasekaran, N.; Arumuga Perumal, D.The intent of the current research work is to emphasize the computational modeling of forced convection heat dissipation in the presence of high porosity and thermal conductivity metallic foam in a horizontal pipe for different regimes of the fluid flow for a range of Reynolds number. A two-dimensional physical domain is considered in which Darcy extended Forchheimer (DEF) model is adopted in the aluminum metallic foam to predict the features of fluid flow and local thermal nonequilibrium (LTNE) model is employed for the analysis of heat transfer in a horizontal pipe for different flow regimes. The numerical results are initially matched with experimental and analytical results for the purpose of validation. The average Nusselt number for fully filled foam is found to be higher compared to other filling rate of metallic foams and the clear pipe at the cost of pressure drop. As an important finding, it has been observed that the laminar and transition flow gives higher heat transfer enhancement ratio and thermal performance factor compared to turbulent flow. This work resembles numerous industrial applications such as solar collectors, heat exchangers, electronic cooling, and microporous heat exchangers. The novelty of the work is the selection of suitable flow and thermal models in order to clearly assimilate the flow and heat transfer in metallic foam. The presence of aluminum metal foam is highlighted for the augmentation of heat dissipation in terms of PPI and porosity. The parametric study proposed in this work surrogates the complexity and cost involved in developing an expensive experimental setup. © 2021 American Society of Mechanical Engineers (ASME). All rights reserved.Item Performance evaluation of partially filled high porosity metal foam configurations in a pipe(Elsevier Ltd, 2021) Jadhav, P.H.; Gnanasekaran, N.; Arumuga Perumal, D.A.; Mobedi, M.In this contemporary research, a parametric analysis of partially filled high porosity metallic foams in a horizontal conduit is performed to augment heat transfer with reasonable pressure drop. The investigation includes six different models filled partly with aluminium foam by varying internal diameter of foams from the wall side and external diameter of foam from the core of the tube. The pore density of the foam ranges from 10 to 45 PPI and their porosity varies from 0.90 to 0.95. Flow dynamics are captured using Darcy Extended Forchheimer model for the porous filled region and two-equation turbulence k-? model employed in clear region of the fluid. The local thermal non-equilibrium assumption is incorporated in porous filled region of the conduit to compute the heat transport characteristics. The results showed that the thermal performance factor of 10 PPI aluminium foam performs close to the 10 PPI expensive copper foam. The performance factor is found to be higher for 30 PPI aluminium foam amongst the PPI's of the foam considered. However, the performance factor is found to be 2.93, 2.22 and 1.73 for 30PPI, 45 PPI and 20PPI with their porosities of 0.92, 0.90 and 0.90, respectively for the model 1, model 2 and model 3 at lower Reynolds number of 4500 and then it decreases progressively with increasing flow rates of the fluid. The results of average wall temperature, average Nusselt number and Colburn j factor are also evaluated to obtain best possible performance. © 2021Item Performance score based multi-objective optimization for thermal design of partially filled high porosity metal foam pipes under forced convection(Elsevier Ltd, 2022) Jadhav, P.H.; Trilok, G.; Gnanasekaran, N.; Mobedi, M.Optimization study in flow through metal foams for heat exchanging applications is very much essential as it involves variety of fluid flow and structural properties. Moreover, the identification of best combinations of structural parameters of metal foams for simultaneous improvement of heat transfer and pressure drop is a pressing situation. In this work, six different metal foam configurations are considered for the enhancement of heat transfer in a circular conduit. The foam is aluminum with PPI varying from 10 to 45 and almost the same porosity (0.90-0.95). The aluminum foams are chosen from the available literature and they are partially filled in the conduit to reduce the pressure drop. For a constant heat flux condition, the goal is to find out the efficient metal foam and configurations when air is considered as a working fluid. A special attention is paid to the preference between pressure drop and heat transfer enhancements. That is why TOPSIS optimization techniques with five different criteria (contains the combination of the weightage/priority of heat transfer and pressure drop) is used. Based on the numerical results of heat and fluid flow in conduit, it is found that when an equal importance is given to both heat transfer and friction effect, 30 PPI aluminum foam with 80% filling on the inner lateral of the pipe provides the best score as 0.8197. The best configuration and PPI for different preferences between friction and heat transfer enhancements is discussed in details. The Reynolds number varies from 4500 to 16500. © 2021 Elsevier LtdItem Numerical assessment of thermal characteristics of metal foams of orderly varied pore density and porosity under different convection regimes(Elsevier Masson s.r.l., 2022) Trilok, G.; Kumar, K.K.; Gnanasekaran, N.; Mobedi, M.The present study is done to analyze heat transfer and fluid flow in a channel with orderly varied pore density and porosity combination of foam samples. Darcy Forchheimer flow and LTNE thermal models are considered to estimate heat transfer characteristics. Considering the effect of orderly varied combinations of the dual structural properties, forced convection over a range of flow velocities and natural convection phenomenon are studied numerically in the channel housing porous samples. Two limiting solutions for Nusselt number (Nu) i.e., Nun (for natural convection) and Nuf (for forced convection) for Ri→∞ and Ri→0 respectively, as a function of independent variable Richardson number (Ri) with structural properties pore density and porosity are obtained with the help of local thermal non-equilibrium (LTNE) thermal model and Darcy-Forchheimer flow model. Further these asymptotic solutions are blended using technique illustrated in the literature in order to obtain solution for Nusselt number for mixed convection (Num). Correlations for Nusselt number as a function of combination of porosity and pore density are obtained emphasizing on the varied significance of these parameters in different convection regime. The present study not only emphasizes on effect of combination of structural properties of metal foams on heat transfer characteristics, but also illustrates a technique that enables to arrive at suitable correlation for an intermediate phenomenon existing between two other extremes, with zero computational cost. Effect of pore density on heat transfer characteristics at a given porosity, is found to be not much influencing in natural convection dominant regime. However, in mixed and forced convection dominant scenario it is illustrated that, effect of variation in pore density and porosity plays a significant role in expressing distinguishable heat transfer characteristics, along with other well-known independent parameters such as porosity and Reynolds number. © 2021 Elsevier Masson SASItem Integrated microchannel cooling for densely packed electronic components using vanadium pentaoxide (V2O5)-xerogel nanoplatelets-based nanofluids(Springer Science and Business Media B.V., 2023) Narendran, G.; Gnanasekaran, N.; Arumuga Perumal, D.A.; Moolayadukkam, M.; Nagaraja, H.S.The present study reports the implementation of novel nanoplatelets-based vanadium pent oxide (V2O5)-xerogel for the application of conjugate cooling in densely packed electronic devices. An integrated heat sink is made up of copper with a channel width of 490 µm and is shrink-fitted into aluminium block that acts as a heat spreader. V2O5-xerogel is synthesized by melt quenching process and characterized based on field emission scanning electron microscope, transmission electron microscope, and X-ray diffraction to analyse the surface morphology of the particles. Studies related to the stability of the nanofluids for different concentrations are discussed in this paper. Furthermore, a study on the effect of pulsating flow in microchannel is performed for different flow rates. As a result, a maximum enhancement of 17% in heat transfer coefficient was observed for the concentration of 0.4 mass% with a flow rate of 200 mL min-1 compared to a pure fluid. Finally, the results reveal that the xerogel is a potential working fluid for heat transfer applications involving microscale devices. © 2023, Akadémiai Kiadó, Budapest, Hungary.Item Numerical analysis of thermo hydro-dynamics behavior of solar flat plate collector with square and V-cut twisted tape inserts(Taylor and Francis Ltd., 2025) Narendran, G.; Jadhav, P.H.; Gnanasekaran, N.Numerical analysis has been conducted for a solar collector with two circular pipes having semi-circular contact with absorber plate. The tubes are analyzed with and without the inclusion of twisted tape inserts of twist ratio Y = 3 and Y = 4. The comparison between the heat transfer and pressure drop characteristics of a plain tube to that fitted with the twisted tape inserts is done and validated against experimental results with good agreement. Additionally, helical twisted tape is modeled with square- and V-cut to analyze its influence on flow and heat transfer phenomenon. V-cut twisted tape inserts act as turbulence promoters, increasing fluid flow and inducing vortex-like motion. As a result, boundary layer around the absorber plate is disrupted with decrease in stagnation temperature, resulting in better heat transfer and more effective absorption and conversion of solar energy. The Nusselt number, friction factor, and heat transfer coefficient variation with the Reynolds number have been studied for the given heat fluxes. It is found that the Nusselt number of the fluid flowing in the plain tube is increased by 76.44% when the tube is fitted with twisted tape inserts. The pressure drop in the tube is found to increase with the presence of the twisted tapes. The average temperature along the length of the circular tube and absorber plate has also been reported. © 2023 Taylor & Francis Group, LLC.