Browsing by Author "Gumtapure, V."

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A comparative study of stanley, lqr and mpc controllers for path tracking application (adas/ad)
(Institute of Electrical and Electronics Engineers Inc., 2019) Vivek, K.V.; Sheta, M.A.; Gumtapure, V.
This paper presents comparative study between Stanley, LQR (Linear Quadratic Regulator) and MPC (Model Predictive Controller) controllers for path tracking application, which is a level 4 automation feature under ADAS/AD (Advanced Driver Assistance System/Autonomous Driving). The accuracy associated with all the controllers are compared by making the vehicle model run in a prescribed environment. The initial designs are done in MATLAB environment and later they are interfaced with IPG CarMaker vehicle simulation tool for fine tuning. Stanley controller is more of an intuitive steering control law where as LQR and MPC are more advanced optimal controllers. The control actions are calculated by optimising the states of the model. Kinematic vehicle model is used with states as errors and a comparator design is made to find the deviation of the vehicle from the prescribed path. The paper gives a detailed idea about the controllers regarding its use, advantages and limitations in this application. Â© 2019 IEEE.
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.
Activated carbon-based dye-sensitized solar cell for development of highly sensitive temperature and current sensor
(Institute of Physics Publishing helen.craven@iop.org, 2019) Dasari, K.K.; Gumtapure, V.
Activated carbon was produced from coconut shells using steam activation method. The process followed by intermediate pyrolysis performed at 575° C. The production yields end products as carbon, biofuels and gases. The developed activated charcoal is implemented as counter electrode in demonstrating Dye Sensitised Solar Cell using naturally available sensitizer. In addition, Dye Sensitised Solar Cell based current and temperature sensors were developed for highly remote optoelectronics applications. Anthocyanin dye extracted from pomegranate juice generated maximum current of 10 mA cm-2. The characteristics of the cell was performed with different optic filters wavelength ranging 400-650 nm and the maximum efficiency was developed for wavelength of 445 nm. © 2019 IOP Publishing Ltd.
Characterization of linear low-density polyethylene with graphene as thermal energy storage material
(Institute of Physics Publishing helen.craven@iop.org, 2019) Chavan, S.; Gumtapure, V.; Arumuga Perumal, D.A.
In this work authors reported the preparation and characterization of composite phase change material (CPCM) using the direct-synthesis method by blending the Linear low-density polyethylene (LLDPE) with Carboxyl Functionalized Graphene (f-Gr). LLDPE is selected as base material and f-Gr is dispersed into three different concentrations 1.0, 3.0, and 5.0 wt% and referred as CPCM-1, CPCM-2 and CPCM-3 respectively. Experimental analysis is carried out through Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM) and Differential scanning calorimeter (DSC). The preset study assesses the influences of nanoparticle concentration on thermophysical properties, thermal performance and thermal storage characteristics of CPCMs. Results show that addition of f-Gr improves the thermal conductivity and latent heat of fusion of LLDPE. However, f-Gr slightly reduces the melting temperature and decreased the crystallization temperature. Therefore, this study reveals that f-Gr, addition to LLDPE has substantial potential for improving the thermal energy storage performance. © 2019 IOP Publishing Ltd.
Comprehensive analysis of blade geometry effects on Savonius hydrokinetic turbine efficiency: Pathways to clean energy
(Elsevier Ltd, 2024) Shanegowda, T.G.; Shashikumar, C.M.; Gumtapure, V.; Madav, V.
The rising global demand for clean and renewable energy has intensified interest in hydrokinetic energy harvesting, with Savonius turbines gaining attention due to their simplicity and low cost. While numerous studies have focused on refining blade designs for wind turbines, limited research has been conducted on water turbines to identify the best design. This study investigates the effect of blade geometry on the efficiency of Savonius hydrokinetic turbines to identify the optimal configuration. Three new blade designs were tested, incorporating inner blades and varying blade numbers. These designs were experimentally evaluated to identify the optimal turbine configuration for maximum efficiency, and the findings were then validated through numerical studies. Rotational analysis was conducted to investigate torque variations across a full turbine rotation from 0° to 360°, and flow characteristic analysis was performed by utilizing pressure and contour plots at critical positions, including 0°, minimum torque coefficient (CT Min), and maximum torque coefficient (CT Max). Results indicate that the 2-blade Savonius turbine achieved the highest efficiency, with a maximum torque coefficient of 0.29 and a power coefficient of 0.22. It demonstrated 63.5 % greater power efficiency compared to the 3-Blade Savonius Turbine, 2.65 times greater than the Segmented Quarter Savonius Turbine, and 2.26 times greater than the Concentric Arc Savonius Turbine. These findings highlight the importance of blade geometry optimization in improving the performance of Savonius turbines for efficient hydrokinetic energy generation. © 2024 The Authors
Computational investigation of bounded domain with different orientations using CPCM
(Elsevier Ltd, 2019) Chavan, S.; Gumtapure, V.; Arumuga Perumal, D.A.
The present work deals with the composite phase change material (CPCM) of 98% paraffin wax and 2% copper nanoparticle, filled into the bounded domain. Effects of orientation (45° 90° 135° and 180°) with different wall heating conditions (base, left and top wall) are analyzed numerically to understand the flow patterns and interface morphology developed during melting/solidification processes. The melting/solidification mechanism exhibited non-uniform flow patterns and irregular morphology which are dependent on geometrical orientations and different wall heating conditions. The results revealed that the bounded domain with different orientations have significant effect on natural convection current formation. As the orientation changes, the heat transfer rate gets influenced significantly and convection currents amplifies. Top wall heating arrangement of 180° orientation shows competence in achieving better thermal performance. © 2019 Elsevier Ltd
Computational investigation on the effect of geometrical parameters on thermal energy storage systems
(Begell House Inc., 2021) Chavan, S.; Gumtapure, V.; Arumuga Perumal, D.
The present work is an attempt to understand the effect of geometry on the heating and cooling characteristics of thermal energy storage systems. Three different geometrical models (square, pentagon, and hexagon) were considered and the thermal storage material used was a composite of paraffin wax (98%) and Al2O3 nanoparticles (2%). The heating and cooling processes were analyzed by applying a constant heat flux. Among the three models, the square model showed a faster melting rate but the cooling rate was too steep. The hexagonal model showed optimum results in both the heating and cooling processes with uniform and smooth variations in the liquid fraction and temperature. Hence, for optimal thermal storage applications the hexagonal model (or its geometries), which is close to the circular model, can be considered. © 2021 by Begell House, Inc.
Cooling packing and cold energy storage
(Elsevier, 2023) Chavan, S.; Manickam, M.; Arumuga Perumal, A.P.; Gumtapure, V.
This chapter is divided into two parts: first part discusses about cooling packing applications of phase change materials, and second part discusses about cold thermal energy storage application of PCM. Consequently, methods of thermal energy storage are briefly explained, specifically for cooling packing applications along with present challenges of the technology. The second part of the chapter discusses in brief about cold thermal energy storage specifically basic working principle, loading of cold thermal energy storage for operational purposes CTES in selecting and characterizing storage media, water versus ice thermal energy storage, PCM used for cold thermal storage, advantages, disadvantages, and finally, battery thermal management system in electric vehicle are discussed in brief with updated knowledge in the field of real-time application. © 2023 Elsevier Ltd. All rights reserved.
Effect of geometry on heating and cooling characteristics for thermal energy storage-A Computational Study
(Toronto Metropolitan University, 2019) Chavan, S.; Gumtapure, V.; Arumuga Perumal, D.A.
In the present work an attempt is made to understand the effect of geometry on heating and cooling characteristics for thermal energy storage applications. Three different geometrical models (square, pentagon and hexagon) are selected and thermal storage material used is composite of paraffin wax (98%) and Al2O3 nanoparticles (2%) [1-2]. The heating and cooling processes are analyzed by applying constant heat flux and the boundary conditions imposed are: Heating cycle (i) Constant heat flux is applied to left wall (for square) and upper left wall (for pentagon and hexagon). Cooling cycle (ii) Constant heat rejection through right wall (for square) and lower right wall (pentagon and hexagon). (iii) Remaining all other walls are Insulated for both the cases. The geometrical 2-D model is created by using ICEMCFD16.0 pre-processing software of ANSYS 16.0 version, in order to interpret the superior results good quality mesh is generated all over the computational domain. At the boundaries, the mesh size is reduced and made a uniform to response imposition of inputs and resolve the boundary layer conflicts. In order to reduce the computational time, relatively larger mesh is maintained at the center part of the domain. To investigate the problem Fluent 16.0 is used and concerned parameters are defined, boundary conditions are imposed and temperature dependent user-defined functions (UDF) are interpreted. The numerical investigation aims to understand the effect of geometry on heating and cooling characteristics using composite phase change material. The streamline patterns, liquid fractions and temperature distribution profiles are analyzed and among the models square and hexagonal model shown quicker melting (completed melting within 4000 sec). The liquid fraction variation is also similar and uniform, the temperature variation during complete melting process is least in square model followed by pentagonal model. However, liquid fraction variation is least in pentagonal model. Temperature variation during heating is maximum in case of hexagonal model (14%) increase in temperature. Liquid fraction variation is uniform and smooth in hexagonal model and consumed 50% less time than pentagonal model. The cooling cycle analysis also explored some interesting results, cooling rate is very quick in square model but for optimal thermal storage unit heat rejection process should not be too steep. Pentagonal model shown insignificant characteristics during both heating and cooling processes. The hexagonal model exhibited uniform and gradual variation in liquid fraction as well as temperature variation during the process. For ideal thermal storage device quicker heating is expected and heat rejection should be gradual and relatively slower (specially for long term storage applications). Among all the cases if only heating is required then square model will be the best selection but to achieve optimal heating and cooling hexagonal model will be the best option. Â© 2019, Toronto Metropolitan University. All rights reserved.
Exergoeconomic Optimization of Low Temperature Solar Driven Organic Rankine Cycle
(Pleiades journals, 2021) Upadhyaya, S.; Gumtapure, V.
Abstract: One of the most promising technologies in the field of distributed energy is the use of installations operating on the so-called organic Rankine cycle (ORC). The ORC technology is applicable for the utilization of low-potential thermal energy of natural or man-made origin. At the same time, in each specific case of using ORC systems, it is important to carry out technical and economic optimization of the project. In this paper, it is proposed to estimate the cost of electricity production by an ORC power unit using an exergoeconomical model. To optimize the system parameters in order to minimize the electricity cost rate, the method of a genetic algorithm is used. The paper presents the results of optimization of the parameters of the ORC system, which includes a solar collector in combination with an ORC power unit. R245fa is used as the working fluid in this analysis. With the help of a mathematical model, the electricity cost is calculated by comparing the costs for each of the components of the ORC system. For a given operating range of parameters of an ORC power unit with an electric capacity of 1.03 kW, a minimum cost rate of $0.056/(kW h) is determined. The optimal parameters of the working fluid in the ORC power unit, at which the minimum electricity cost can be obtained, are also determined. © 2021, Pleiades Publishing, Inc.
Experimental analysis on humidification-dehumidification desalination system using different packing materials with baffle plates
(Elsevier Ltd, 2021) Thanaiah, K.; Gumtapure, V.; Mitiku Tadesse, G.
The primary objective of the present work is to address the issue of the water scarcity problem facing us globally. This manuscript also attempts to incorporate a Humidification-Dehumidification Desalination Technique (HDHT) using artificial and bio-based packing materials. The thermodynamic analysis of a Humidification-Dehumidification Desalination System (HDHDS) by mathematical and experimental methods is studied in detail. To produce the maximum amount of fresh water, two configurations are developed and analyzed under weather conditions prevailing in South India (INDIA). First, the experiments were carried out with artificial packing material (Polypropylene) with and without baffle plates. Next, the second set of configurations used bio-based packing material (Paddy grass) with and without baffle plates. The present analysis inferred that the volumes of fresh water produced were 0.39, 0.46, and 0.73 kg/h without, and with artificial and bio-based packing materials. The rate of fresh water production increased to 36.30% and 46% for artificial and bio-based materials respectively. There was an increase observed in Gain Output Ratio (GOR) as well in the range of 0.28, 0.40, and 0.65 without, and with artificial, and bio-based packing material. GOR increased up to 30% and 56%, when using artificial and bio-based packing material respectively. The present study reveals that the bio-based packing material is highly advantageous in the production of fresh water and in achieving better GOR. © 2021 Elsevier Ltd
Experimental investigation of melting and solidification characteristics in a vertical shell and tube latent heat thermal energy storage system with novel directional flow annular fins
(Elsevier Ltd, 2025) Naik, L.; Gumtapure, V.; B.V., B.V.
In this study the impact of novel directional flow annular fins on the charging and discharging process in a vertical shell and tube latent heat thermal energy storage system (LHTES) with phase change materials (PCM) is examined. Consequently, the tube carrying heat transfer fluid (HTF) is surrounded by five annular fins. To examine the impact of directional flow fins on the thermal performance of LHTES, four novel directional flow fin configurations namely, 1 mm thick solid circular fin, 10 mm thick hollow circular fin - flow of HTF only through the central tube, 10 mm thick hollow circular fin - flow of HTF partially through the central tube and partially through the fin structure, 10 mm hollow circular fin - flow of HTF only through the fin structure were selected. In order to study the LTHES experimentally, three sections are chosen for the location of thermocouples at 0, 120 and 240°. At each sections five thermocouples are located to record the temperature distribution in the PCM. A detailed behavior of melting and solidification cycles are explained by observing temperature variation, accumulative energy and melting fraction during both melting and solidification. Results show that use of directional flow fins decreases melting time by 58.33 % in comparison with conventional fins and solidification time by 50 % of LHTES and allows heat to penetrate deeper through the volume of the PCM more uniformly. Additionally, the thermal efficiency of the LHTES system was found to be 67.4 % during charging and 53.85 % during discharging, validating the significant improvement in energy storage and retrieval performance with directional flow fins in latent heat thermal energy storage system. © 2025
Experimental investigation of methane-enriched biogas in a single cylinder diesel engine by the dual fuel mode
(Taylor and Francis Ltd., 2022) Chandrashekar, J.; Gumtapure, V.
In this experimental work characteristic such as performance, combustion and emission of a single cylinder, four-stroke constant speed, direct injection, water-cooled diesel engine is investigated. The engine is operated by dual fuel mode using methane-enriched biogas (88.10%-CH4 + 11.89%-CO2) obtained from the food waste. Biogas (BG) is inducted into the engine at intake manifold with various mixtures like BG20, BG30 and BG40 mixed with air (i.e. BG40-40% of CH4 by mass respectively) at actual injection timing of 27.5° before top dead centre (bTDC) for different loads. The performance, combustion and emission characteristics of the engine operated by dual fuel mode were experimentally investigated, and compared with respect to diesel. By observing the experimental results, BG40 was optimized on the basis of lesser emissions and improved performance. BG40 showed lesser brake thermal efficiency and higher brake specific energy consumption than BG20 and BG30 for all loads. On the other hand, BG40 showed lower BTE by 15.5% and 15.62% compared to diesel at 3/4th and full load. Whereas the cylinder peak pressure for BG40 is higher than diesel by 5.36% and the net heat release rate is 14.9% higher than the diesel at full load. BG40 emitted higher carbon monoxide (CO) emissions than diesel by 5% at full load. The nitrogen oxide (NOx) emission for BG40 was lesser by 26.60% than diesel at full load, whereas the soot emission was 22.71% lower than diesel at full load respectively. © 2022 Taylor & Francis Group, LLC.
Experimental investigation of shellac wax as potential bio-phase change material for medium temperature solar thermal energy storage applications
(Elsevier Ltd, 2022) B.V., B.V.; Thanaiah, K.; Gumtapure, V.
Thermal performance of shellac wax as a novel bio-phase change material (BPCM) and Therminol®-55 as heat transfer fluid (HTF) in a vertical shell and tube latent heat thermal energy storage (LHTES) unit is analyzed experimentally. Operational parameters considered, namely HTF flow rate and inlet temperature in the range of 2–5 LPM and 100–120 °C, respectively. The comprehensive study of contours and plots reveals the impact of natural convection and the progress of the melting and solidification front in the charging and discharging process. As the HTF flow rate increases, the charging rate improves considerably, and a maximum reduction in melting time is obtained as 43.6% for 4 LPM. The maximum reduction in melting time and storage efficiency are 42.2% and 73.4%, respectively, at 120 °C and 4 LPM. However, the discharging process's increased flow rate has no significant effect on solidification and discharge efficiency, which attributes the dominant mode of heat transfer is conduction during the solidification. Shellac wax storage efficiency is comparable to existing paraffin wax, stearic acid and palmitic acid-based LHTES unit. In this regard, shellac wax can be a potential Bio-PCM for medium temperature range (60–80 °C) solar thermal applications such as domestic water heating and food drying. © 2021 International Solar Energy Society
Experimental Investigation of Two- and Three-Blade Savonius Hydrokinetic Turbine for Hydropower Applications: A Study across Various Turbine Positions from Channel Centre to Channel Wall †
(Multidisciplinary Digital Publishing Institute (MDPI), 2023) Gangashanaiah, S.T.; Shashikumar, S.; Gumtapure, V.; Madav, V.
Hydrokinetic energy has gained significant attention in recent years as a promising renewable energy source due to its low environmental impact and potential for use in remote locations. This research aims to optimize the performance of the Savonius hydrokinetic turbine, a crucial component of zero-head hydropower systems, for efficient renewable energy extraction from flowing water. Laboratory-scale experiments with two and three-blade Savonius turbines at different channel positions investigate geometric dimensions and design parameters like the power coefficient (CP) and Torque coefficient (CT). The experimental results are compared with previous research, confirming the superiority of the two-blade configuration, which achieved CP and CT at the same TSR and channel locations. Specifically, the two-blade Savonius turbine demonstrated a CP of 0.27 and a CT of 0.37 at TSR 0.7 and the channel’s centre placement. Placing the turbine at the channel centre yields the best performance for both configurations. This study provides valuable insights for enhancing the efficiency of hydrokinetic turbines, contributing to renewable energy technology advancements, and addressing climate change and energy security challenges. The Savonius hydrokinetic turbine has the potential to be a sustainable energy source. © 2023 by the authors.
Experimental studies on cyclic variations in a single cylinder diesel engine fuelled with raw biogas by dual mode of operation
(Elsevier Ltd, 2020) Jagadish, C.; Gumtapure, V.
In this research work, cycle-by-cycle variations of a single cylinder, diesel engine operated with raw biogas is investigated. The biogas used to run the engine is obtained from food waste and as the composition of 88.10%-CH4 + 11.895%-CO2. To study the combustion characteristics, the naturally aspirated diesel engine is converted into dual mode by inducting the biogas into the intake manifold for different proportions from BG20 to BG60 with a step of 10% is mixed with air (i.e. BG60-60% of biogas by mass) respectively. Combustion parameters are measured and recorded by the means of the data acquisition system (DAQ) for 100 combustion cycle. By determining the parameters such as standard deviation, coefficient of variation and return map, the cycle variability is analyzed. From the experimental result, it is observed that as the engine is operated at higher loads and as the biogas is increased from BG20 to BG60 the cyclic variations for maximum cylinder pressure (Pmax) and indicated mean effective pressure (IMEP) increases. Coefficient of variation of Pmax for BG20 and BG40 is lower by 2.3% and 11.98% as compared to diesel. From time return map, BG40 showed good combustion stability and lesser NOx emission compared to diesel. © 2020 Elsevier Ltd
Experimental Study on the Effect of Injection Timing on a Dual Fuel Diesel Engine Operated With Biogas Derived From Food Waste
(American Society of Mechanical Engineers (ASME), 2022) Chandrashekar, J.; Gumtapure, V.
The present work emphasizes the effects of injection timing on the characteristics of a 5.2-kW powered four-stroke diesel engine using biogas and its heat loss analysis. The biogas is obtained from food waste consisting of methane (CH4)-88.1% and carbon dioxide (CO2)-11.8% as the composition. The biogas (BG) is selected by mass basis ranging from 20% to 60% with 10% increments and is used to operate the engine by dual-fuel mode. The effect of three injection timings such as 25.5 deg (retarded), 27.5 deg (actual), and 29.5 deg (advanced) before top-dead center (bTDC) under dual-mode operation to enhance the properties of the engine is studied, and the results are compared with diesel mode at actual injection timing. Maximum brake thermal efficiency of 30.1% was observed for BG20 operated at 29.5-deg bTDC injection timing (IT). The dual mode operated at the injection timing of 29.5-deg bTDC showed an increase in cylinder pressure compared to diesel by 11.9% at full load conditions, whereas carbon monoxide emission was lower by 5.2% at 29.5-deg bTDC IT than diesel, and nitrogen oxide emission was lower at 25.5 deg bTDC IT than diesel mode by 45%. Besides, at 75% engine load, the least amount of heat losses was observed for BG50 exhibiting effective conversion of fuel energy into equivalent work higher than that of diesel by 2.2%, respectively. © © 2022 by ASME.
Numerical analysis of polyethylene based nano-enhanced phase change material in cylindrical storage system
(Taylor and Francis Ltd., 2024) Sheikh, M.I.A.R.; Gumtapure, V.; Ahammed, M.E.
Environmental sustainability encompasses various dimensions like waste management, energy conservation, and environmental impact. The use of waste plastic; Linear Low-density polyethylene (LLDPE) as a phase change material (PCM) offers a sustainable solution for energy and the environment. This study investigates LLDPE/ functionalize graphene composites for latent heat storage using a shell and helical coil for effective energy conversion. The simulation is carried out for constant flux and constant temperature heat supply to understand the influence of nano additives and geometrical parameters such as spiral coil diameter (Dc), pitch (Pc), and orientation of storage unit (θ). The result reveals that nano additive influence effectively and reduces the charging time approximately from 20 to 40% for 1–5% of nano-addition. Simulation results reveals that the spiral coil diameter is crucial for melting and heat transmission. The overall melting time is decreased by up to 56% by increasing the spiral coil diameter from 21 to 49 mm for LLDPE while the effect of pitch length variation is found not significant. The constant temperature heating at 160, 250 and 340°C gives effective results for charging time improvement. The geometrical orientations from 0 to 90 degrees report that the horizontal position is the best orientation for energy storage. © 2024 Informa UK Limited, trading as Taylor & Francis Group.
Numerical analysis of Savonius hydrokinetic turbine performance in straight and curved channel configurations
(Elsevier Ltd, 2025) T G, S.; Shashikumar, S.; Gumtapure, V.; Madav, V.
The global shift towards renewable energy has driven research into efficient hydrokinetic energy harvesting, particularly using Savonius turbines for their simplicity and adaptability to low-flow environments. While previous studies have focused primarily on straight channels, the impact of channel bends, commonly found in agricultural canals, rivers, and irrigation channels, remains underexplored. The present 3D transient numerical study addresses this gap by investigating the performance of Savonius hydrokinetic turbines in channels with 30°, 60°, and 90° bends, evaluating their efficiency under varying flow conditions. The research aims to evaluate the impact of these channel bends on key performance parameters such as the tip speed ratio (TSR), torque coefficient (CT) and power coefficient (CP), supported by detailed pressure and velocity contour analyses. The turbine positioned in the 30° bend emerged as the most efficient configuration, achieving a CTmax of 0.29 at 0.7 TSR and CPmax of 0.24 at 1.0 TSR. The 60° and 90° bends exhibited efficiency reductions of 15 % and 30 %, respectively, due to adverse pressure gradients and increased turbulence. Velocity contour plots demonstrated reduced wake regions and optimized flow reattachment for the 30° bend, while pressure contour analysis indicated lower drag forces on the advancing blades. This study highlights the potential of using Savonius turbines in agricultural channels, recommending the 30° bend as the optimal channel configuration to maximize turbine efficiency, providing a sustainable solution for energy generation in rural and low-flow environments. © 2025
Numerical and experimental analysis on thermal energy storage of polyethylene/functionalized graphene composite phase change materials
(Elsevier Ltd, 2020) Chavan, S.; Gumtapure, V.; Arumuga Perumal, A.P.
The main driving force behind the present work is environmental issues caused due to the usage of plastics, and energy issues. Current work attempts to address these problems by converting recycled plastics into thermal storage materials (TSM). Unfavorable thermophysical properties of plastic make it impractical but these inadequacies can be amended by blending with additives of superior thermophysical properties like, functionalized graphene. Numerical and experimental analysis are carried out to assess the thermal performance of TSMs (LLDPE, CPCM-1, CPCM-2 and CPCM-3) and check the compatibility of the materials. The phase change temperature of TSM is 123 to 125 °C and heat of fusion is 71.95 to 97 kJ/kg. Several thermal characteristics are analyzed to assess thermal performance and the amount of heat energy supplied, rate of heat transfer, and heat storage efficiency are deliberated. Results shown energy level enhancement of 43.17, 50.42, 54 and 50.61% for LLDPE, CPCM-1, CPCM-2 and CPCM-3 respectively. Among the TSM CPCM-2 shows relatively better storage capability (54% enhancement) due to incorporation of optimum concentration of enhancing material. The solidification process takes place through convection and radiation mode of heat transfer, at the completion of solidification process the TSM energy content reduces to 97.5, 96, 96 and 96% for LLDPE, CPCM-1,CPCM-2 and CPCM-3 respectively. This work concludes that, recycled plastics can be blended and it can be converted into efficient thermal storage material. © 2019 Elsevier Ltd