Conference Papers

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Author: search.filters.author.Samuel, A.

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    Heat Transfer Characteristics and Cooling Performance of Treated Kitchen Coconut Oil
    (ASM International, 2021) Roy, S.S.; Samuel, A.; Prabhu, K.N.
    Quenching is one of the most basic and widely used heat-treatment processes. Mineral Oil or petroleum oil base stocks are the conventional quench media used for quench hardening heat treatment since the 19th century. However, mineral oils are not environment friendly as they are toxic, non-biodegradable, and non-renewable. Many alternative ecofriendly quenchants have been developed to replace mineral oil such as vegetable oils, polymer quenchants, and nanofluids. Although most of the vegetable oils show superior cooling performance to mineral oil, their practical application is limited owing to their high cost of production and low thermal stability. In this study, the kitchen coconut oil was chemically treated and its cooling performance and heat transfer characteristics were assessed and compared with that of refined coconut oil and mineral oil. The thermophysical properties of chemically treated waste cooking oil were found to be higher than refined and mineral oils. Chemically treated oil showed better wettability. The quenching experiments were conducted using an Inconel 600 standard probe according to ISO 9950 and ASTM D 6200 standards. The vapor blanket stage was shorter for the chemically treated oil as compared with refined and mineral oils. Inverse heat conduction problem (IHCP) was solved for estimating heat flux transients from the temperature data and thermo-physical properties of the Inconel probe. The average peak heat flux was highest for chemically treated oil compared to both refined coconut oil and mineral oil. © © 2021 ASM International® All rights reserved.
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    Estimation of Heat Flux Transient During Quench Hardening of Varying Diameter Steel Probes Using IHCP-Phase Transformation Coupled Model
    (ASM International, 2023) Samuel, A.; Nayak, U.V.; Pranesh Rao, K.M.P.; Prabhu, K.N.
    The phase transformation model is coupled with the inverse heat conduction problem (IHCP) to estimate the steel/quenchant interfacial heat flux. Cylindrical steel probes having section thicknesses 25 and 50mm, respectively, and lengths 30mm were made from medium and high carbon steels (AISI 1045 and 52100). The probes were quenched in mineral, neem, and sunflower oils. The cooling curves at the centre and near the surface of steel probes were recorded. The near-surface cooling curve was used as a reference temperature data in the IHCP algorithm for the estimation of surface heat flux, whereas the cooling curve at the centre was used as the boundary condition of the axisymmetric model of the probe. The effect of phase transformation on the metal/quenchant interfacial heat flux was indicated by a kink and rise of heat flux. The increase in the section thickness of the probe from 25 to 50mm decreased the magnitude of the heat flux. Increasing section thickness increases the phase transformation, increasing the resistance to heat flow at the metal/quenchant interface. © © 2023 ASM International®