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    Biodiesel from Biomass Waste Feedstock Prosopis Juliflora as a Fuel Substitute for Diesel and Enhancement of Its Usability in Diesel Engines Using Decanol
    (Wiley-V C H Verlag Gmbh, 2023) Duraisamy, Boopathi; Velmurugan, Kandasamy; Venkatachalapathy, V. S. Karuppannan; Madheswaran, Dinesh Kumar; Varuvel, Edwin Geo
    Biomass-based biofuel production is a promising solution to the decline of fossil fuels. Prosopis juliflora seed-derived vegetable oil, known as Prosopis juliflora methyl ester (JFME), offers a potential feedstock for biodiesel. To enhance its properties, the addition of Decanol is investigated, a higher-order alcohol similar to Diesel. Experiments are conducted on a 5.2 kW compression ignition (CI) engine using JFME blended with different decanol concentrations (5%, 10%, 15%, and 20%). Fourier-transform infrared spectroscopy and gas chromatography-mass spectrometry analysis confirm its compliance with fuel standards. The findings reveal that the 20% decanol blend (D20) achieves a brake thermal efficiency of 29.9% at full load, with reduced NO, smoke, and hydrocarbon (HC) emissions compared to diesel. D20 shows NO emissions of 1265 ppm, smoke opacity of 53%, and HC emissions of 69 ppm, while diesel records 1320 ppm, 69%, and 75 ppm, respectively. The CO emissions for D20 are 0.359 vol%, slightly higher due to decanol's higher latent heat of evaporation. Moreover, D20 exhibits improved combustion with a higher mass fraction burnt and faster heat release rates. These results indicate the potential of using JFME blended with 20% decanol as an alternative fuel for CI engines, offering higher performance and reduced emissions.
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    Nanofluids as a coolant for polymer electrolyte membrane fuel cells: Recent trends, challenges, and future perspectives
    (Elsevier Sci Ltd, 2023) Madheswaran, Dinesh Kumar; Vengatesan, S.; Varuvel, Edwin Geo; Praveenkumar, T.; Jegadheeswaran, Selvaraj; Pugazhendhi, Arivalagan; Arulmozhivarman, J.
    In this comprehensive review, we critically examine the application of nanofluids as coolants in PEMFCs, explicitly focusing on elucidating their thermal efficiency enhancement mechanisms. In addition to the existing research, the significant areas critically reviewed include the influence of nanoparticle size and concentration, surface modification techniques, characterization methods, nanofluid stability under different conditions, nanofluid behavior in various flow regimes, and the impact of nanofluids on system performance and efficiency. A meticulous analysis of the most recent studies involving single nanofluids (Al2O3, SiO2, TiO2, ZnO, BN) and hybrid nanofluids (CuFeAl, Al2O3:SiO2, Bio glycol+Al2O3:SiO2, TiO2:SiO2) underscores their potential to revolutionize PEMFC cooling systems. Findings reveal that nanofluids exhibit remarkable enhancements in heat transfer, offering a 20-27% reduction in radiator size compared to traditional coolants. The science underpinning this enhancement is multifaceted, characterized by self-deionization phenomena, nanoparticle dispersion stability via Brownian motion, and unprecedented inter-atomic interactions. Notably, nanofluids effectively eliminate particle sedimentation and coagulation, ensuring sustained heat transfer performance over extended operational periods. However, several challenges are observed, such as the limited exploration of electrical conductivity, which occurred because of the correlation between the net-charge influence of the suspended particle and electrical double layer (EDL) behavior. Furthermore, understanding and utilizing smart nanofluids and nanobubbles demand rigorous investigation for optimal cooling strategies. Future research should focus on standardizing nanofluid synthesis and characterization protocols, elucidating the underlying heat transfer mechanisms, addressing cost and scalability issues, and ensuring nanofluids' durability in PEMFCs. The review's timeliness lies in its relevance to the current advancements and challenges in the field, offering valuable insights for researchers and practitioners working in the thermal management of PEMFC.
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    Polymer based flow field plates for polymer electrolyte membrane fuel cell and the scope of additive manufacturing: A techno-economic review
    (WILEY, 2022) Madheswaran, Dinesh Kumar; Jayakumar, Arunkumar; Velu, Rajkumar; Raj, Rajendran; Varuvel, Edwin Geo
    Flow field plate (FFP) is an integral polymer electrolyte membrane fuel cell (PEMFC) stack component that has multifunctional applications, such as facilitation of the reactant flow, transfer current from cell-to-cell, heat dissipation and product water removal. The conventional FFPs are made of graphite or metals, with their limitations, such as low corrosion resistance, heavyweight, high-cost and complex manufacturability, which hinders the commercialization of PEMFCs. On the contrary, polymer composites are lightweight and low-cost materials with good anti-corrosion attributes. It is also evident that polymer composites are the primary choice of material in a wide range of additive manufacturing (AM) processes, given their unique attributes such as design freedom, the capability to fabricate intricate flow channel geometry and minimize material wastage. However, incorporating the AM process for FFP design involves substantial challenges and consequently the present paper performs a comprehensive review on the diverse literature limited to polymer composite FFPs developed in recent years (2011-2021) with an intention of providing a holistic insight on development of cost-effective, high-strength-weight FFPs. The review also provides the prospectus of applying AM technology for fabricating polymer-based composites for FFP applications. Finally, a holistic meta-analysis is performed on strength and weakness of using polymer composite FFP, and the outlook is summarized.
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    Recent advancement on thermal management strategies in PEM fuel cell stack: a technical assessment from the context of fuel cell electric vehicle application
    (TAYLOR & FRANCIS, 2022) Madheswaran, Dinesh Kumar; Jayakumar, Arunkumar; Varuvel, Edwin Geo
    Effective thermal management strategy for the polymer electrolyte membrane fuel cell (PEMFC) stack is critical in maintaining the overall stack efficiency and durability. The present assessment critically explores the recent developments (predominantly last decade) in thermal management strategies of PEMFCs, which encompasses an in-depth analysis of the thermodynamics, corresponding effects on components of PEMFC and the waste heat recovery system. In general, the operating temperature range of a PEMFC is 60-80 degrees C. Entropy consequence and irreversible transport mechanisms of the reactants are the major contributions to heat generation. Air cooling is employed for compact stacks of less than 5 kW and water cooling is favored for stacks greater than 5 kW. Cooling using nanofluids enables better cooling efficiency than water while downsizing the size and weight of the system. Phase change cooling strategy to attain greater heat removal capacity is broadly employed for stacks greater than 10 kW, which is beneficial in a compact size of the cooling system contrasted to the water cooling system. Passive cooling methods employing vapor chamber, heat pipes and heat spreaders used were another cooling system for stack power ranges between 5 and 10 kW which have the benefit of reduced parasitic losses. In addition to thermal management strategies, integral challenges associated with each thermal management strategy is identified. Discussion on cold start thermal management of fuel cell electric vehicles was provided. Finally, the waste heat recovery system of energy efficiency and overall future prospectus for the betterment of thermal management of PEMFC is emphasized.