Journal Articles

Permanent URI for this collectionhttps://idr.nitk.ac.in/handle/123456789/19884

Browse

Author: search.filters.author.Gumtapure, V.

Search Results

Now showing 1 - 10 of 30
  • No Thumbnail Available
    Item
    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.
  • No Thumbnail Available
    Item
    NUMERICAL INVESTIGATION ON SHEAR-INDUCED MIGRATION OF ERYTHROCYTES IN IRREGULARLY CURVED CORONARY STENOSED ARTERIES
    (World Scientific, 2025) Vasmate, S.; Gumtapure, V.
    Endothelial cells in large arteries receive less oxygen from migrating erythrocytes (Red Blood Cells) due to stenosis, which alters flow patterns. This investigation has been carried out to study how stenosis severity affects red blood cell (RBC) concentration distribution, shear-induced diffusion (SID), and wall shear stress (WSS) in irregular curved artery geometries with varying degrees of stenosis (DOS) 30%, 50%, 70%, and 90%. Most of the researchers’ studies focused on idealized straight geometries, whereas this work utilizes multiphase mixture theory simulations to mimic an accurate coronary arteries model of irregular curved geometries. A non-Newtonian viscosity model by Krieger and Phillips’s shear-induced diffusive flux model (DFM) is integrated to represent hemodynamics better. The multiphase transient non-Newtonian three-dimensional (3D) computational fluid dynamics (CFD) models have been used for variation DOS. A pulsatile blood flow condition is incorporated to study flow conditions in the curved coronary arteries. The results show that SID increases WSS by 82.98% between 70–90% of DOS, which indicates stenosis severity plays a significant role. At 90% stenosis, throat average velocity increased by 50 times compared to 30% stenosis, concentrating RBCs at the center and lowering blood viscosity and WSS at the wall. Clinically relevant findings suggest that sites with low WSS and reduced RBC concentration, as observed in this study, are closely linked to atherosclerosis development. These insights highlight the importance of SID and RBC distribution in understanding arterial stenosis and its results in cardiovascular disorders. © 2025 World Scientific Publishing Company.
  • No Thumbnail Available
    Item
    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.
  • No Thumbnail Available
    Item
    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
  • No Thumbnail Available
    Item
    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.
  • No Thumbnail Available
    Item
    Parametric analysis and thermodynamic optimization of organic rankine cycle for low grade waste heat recovery
    (Scientific Publishers, 2019) Upadhyaya, S.; Gumtapure, V.
    The system consists of a low temperature heat source coupled to an organic rankine cycle (ORC) system. The working fluids used are R245fa, R123, isobutane and R134a. The ORC model is developed in EES by adopting zero- dimensional energy and mass balance approach. A parametric investigation has been carried out to study the impact of few thermodynamic parameters on the performance of the system. Genetic algorithm optimization technique is adopted to find the optimal parameters at which the system can be operated with maximum exergy efficiency. Maximum exergy efficiency of 45.53% was obtained with R123 followed by R245fa (44.98%), isobutane (42.89%) and R134a (41.91%). The optimal turbine inlet pressure for R245fa, R123, isobutane and R134a was 6.07 bar, 3.66 bar, 10.36 bar and 19.94 bar, respectively. Sensitivity analysis showed that the turbine inlet pressure has the highest sensitive degree with respect to all performance indicators when compared with other system parameters. Variation in pinch point temperature difference showed no impact on thermal efficiency. R245fa and R123 are better suited for low temperature ORC systems compared to R134a and isobutane due to their efficient system performance and low operating temperatures and pressures. © 2019 - Kalpana Corporation.
  • No Thumbnail Available
    Item
    Thermal property study of fatty acid mixture as bio-phase change material for solar thermal energy storage usage in domestic hot water application
    (Elsevier Ltd, 2019) B.V., R.M.; Gumtapure, V.
    For the correct design, simulation and specific application of the latent heat thermal energy storage (LHTES) system, detailed evaluation of phase change material (PCM) properties are essential. Present study aims to analyze the thermal and volume dependent behavior of available organic Bio-PCM OM55, using conventional thermal gravimetric analyzer (TGA), thermal constant analyzer (TCA), differential scanning calorimeter (DSC) and in-house T-history method (THM). Execution of the mentioned thermal analysis outcome with significant information of OM55. TGA shows that OM55 is thermally stable within the operating temperature 45–60 °C, because the maximum permissible degradation temperature 154.6 °C is much higher than operating temperature range. The OM55 has considerable thermal conductivity compared to the existing PCM, which is already used in domestic solar water heating (DSWH) applications. The evaluation of transition temperature, isothermal enthalpy, and specific heat by THM are well compared with the DSC analysis. Comparison of DSC and THM analysis showed that the behavior of OM55 is volume independent. The overall study concluded that OM55 is a potential Bio-PCM. However, for the optimum amount of energy storage and discharge in OM55, it is recommended to operate the LHTES unit over a temperature range between 46–59 °C for domestic hot water application. © 2019 Elsevier Ltd
  • No Thumbnail Available
    Item
    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
  • No Thumbnail Available
    Item
    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
  • No Thumbnail Available
    Item
    Thermo-physical analysis of natural shellac wax as novel bio-phase change material for thermal energy storage applications
    (Elsevier Ltd, 2020) B.V., B.V.; Gumtapure, V.
    The high energy density of latent heat storage makes it more competent than other types of thermal energy storage (TES) systems. Studying thermophysical and rheological properties of phase change material (PCM) is required for effective storage design, simulation, and applications. Bio-based PCM (BPCM) is a renewable and eco-friendly option for commercial paraffin-based PCMs. This study intends to characterize the shellac wax using the conventional and non-conventional approach as novel BPCM. Analysis of Fourier transforms infrared spectrophotometer (FTIR) indicates that shellac wax has aliphatic hydrocarbons, carboxylic acid, alcohol, and esters functional group. Thermogravimetric analysis (TGA) shows shellac wax has no mass change for operating temperature range (50–85 °C). Differential scanning calorimetry (DSC) analysis reported enthalpy of melting and crystallization as 148 kJ/kg and 161 kJ/kg, respectively. The crystallization enthalpy measured in the T-history method (THM) is 210.5 kJ/kg. However, DSC analysis of sample undergone 0,100,200 and 300 thermal cycle shows no significant change in thermal properties. Other properties like thermal conductivity, density, specific heat and viscosity are comparable to the present PCM used in storage applications. The overall study outcome that shellac wax is thermally stable and is potential BPCM for the TES application like solar desalination, district heating, waste heat recovery and solar cooking. © 2020 Elsevier Ltd